JP7540236B2 - Capping Device - Google Patents

Description

The present invention relates to a capping device used in a liquid ejection device that ejects liquid onto a medium.

The liquid ejection device described in Patent Document 1, which is an example of a liquid ejection device, includes a cap mechanism that comes into contact with the liquid ejection head to form a space surrounding the nozzle, and uses suction to discharge thickened liquid and air bubbles from within the liquid ejection head. The liquid ejection device also includes a cap device that comes into contact with the liquid ejection head to form a space surrounding the nozzle, and supplies a moisturizing liquid, which is an example of a humidifying fluid, from a moisturizing liquid storage unit, which is an example of a humidifying fluid storage unit, through a connecting flow path to humidify the nozzle. In other words, a liquid ejection device is disclosed that is provided with the cap mechanism and the cap device for maintenance purposes, thereby not only preventing nozzle clogging but also suppressing drying of the nozzle.

JP 2019-38159 A

In the liquid ejection device described in Patent Document 1, for maintenance purposes, the liquid ejection head moves from the ejection area where printing is performed on the medium to a maintenance area outside the ejection area. That is, the cap of the capping mechanism and the cap of the capping device are arranged side by side in the movement direction of the liquid ejection head in the maintenance area. This requires space for both caps, which makes the liquid ejection device larger.

The capping device that solves the above problem is a capping device that can form a space surrounding the opening of a nozzle when it comes into contact with a liquid ejection head having a nozzle that ejects liquid, and is equipped with a cap having a recess that forms the space, a humidification chamber having an inlet through which humidification fluid flows in to humidify the space, and an outlet through which the humidification fluid flows out, and a gas-permeable partition that separates the recess from the humidification chamber, and the recess has a hole that can discharge liquid that has been ejected from the liquid ejection head into the cap.

FIG. 1 is a perspective view showing a liquid ejection device according to an embodiment. FIG. 2 is a schematic diagram showing the arrangement of components around a liquid ejection head. FIG. 3 is a schematic front view of the components as viewed from the direction along the discharge direction in FIG. 2 . 3 is a schematic front view of the components as viewed from a direction along the first transport direction in FIG. 2 . FIG. 4 is an exploded perspective view of the unit cap shown in FIG. 3 as viewed obliquely from above; FIG. 4 is an exploded perspective view of the unit cap shown in FIG. 3 as viewed obliquely from below. FIG. 6 is a plan view of the humidifying chamber as viewed from the direction along the discharge direction in FIG. 5 . FIG. FIG. 9 is a schematic diagram showing the flow of liquid in FIG. 8 by arrows. FIG. 9 is a schematic diagram showing the gas flow in FIG. 8 by arrows. FIG. 2 is a schematic diagram showing a configuration of a capping device. FIG. 2 is a block diagram showing an electrical configuration of the liquid ejection device. 5A and 5B are schematic diagrams showing the state of the humidification fluid when the circulation operation is performed. 11 is a flowchart showing a circulation operation. 5A and 5B are schematic diagrams showing the state of the humidification fluid when the concentration adjustment operation is performed. 11 is a flowchart showing a density adjustment operation. 6A and 6B are schematic diagrams showing the state of the humidification fluid when the cap replacement preparation operation is performed. 11 is a flowchart showing a cap replacement preparation operation. 11A and 11B are schematic diagrams showing the state of the humidification fluid when the pre-exchange operation of the moisture containing unit is performed; 11 is a flowchart showing an operation before replacing the moisture storage unit. 5A and 5B are schematic diagrams showing the state of the humidification fluid when the humidification fluid filling operation is performed; 6 is a flowchart showing a humidification fluid filling operation.

Below, an embodiment of a liquid ejection device, a capping device used in the liquid ejection device, and a maintenance method for the capping device used in the liquid ejection device will be described with reference to the drawings. The liquid ejection device is, for example, an inkjet printer that prints by ejecting ink, which is an example of a liquid, onto a medium such as paper.

In the drawings, the liquid ejection device 11 is placed on a flat surface, with the width and depth directions being substantially horizontal. The vertical direction is indicated as the Z axis, and the directions along the plane intersecting the Z axis are indicated as the X and Y axes. The X, Y, and Z axes are preferably mutually perpendicular. In the following description, the X-axis direction is also referred to as the width direction X, the Y-axis direction as the depth direction Y, and the Z-axis direction as the vertical direction Z.

<Configuration of Liquid Ejection Apparatus>
1, the liquid ejection device 11 includes a rectangular parallelepiped main body 12, an image reading unit 13 attached to the upper portion thereof, and an automatic feed unit 14. The liquid ejection device 11 has a configuration in which the main body 12, the image reading unit 13, and the automatic feed unit 14 are stacked in this order from the bottom in the vertical direction Z.

The image reading unit 13 is configured to be capable of reading images such as characters and photographs recorded on a document. The automatic feeding unit 14 is configured to be capable of feeding a document toward the image reading unit 13. The image reading unit 13 also has an operation unit 15 that is operated when giving instructions to the liquid ejection device 11. The operation unit 15 has, for example, a touch panel type liquid crystal screen and operation buttons.

The main body 12 has multiple medium storage sections 16 capable of storing media such as paper. In this embodiment, the main body 12 has a total of four medium storage sections 16. The medium storage sections 16 are configured to be removable from the main body 12. The main body 12 also has a recording section 20 that records on the medium M within the main body 12. The recording section 20 is equipped with a head unit 24 having a liquid ejection head 21 capable of ejecting liquid. Furthermore, the main body 12 has a mounting section 17 on its upper portion on which the medium M on which recording has been performed is placed. The mounting section 17 has a mounting surface 17a on which the medium M is placed. It should be noted that the number of medium storage sections 16 may be only one.

The medium M contained in the medium storage section 16 is transported along the transport path 19 from the medium storage section 16 through the recording section 20 to the mounting section 17. A feed roller (not shown) rotates in contact with the topmost medium M among the multiple media M contained in the medium storage section 16, thereby sending the topmost medium M from the medium storage section 16 to the recording section 20 located above the medium storage section 16. As the medium M passes through the recording section 20, the liquid ejection head 21 ejects liquid toward the medium M, and the ejected liquid adheres to the medium M to record. After recording, the medium M is ejected toward the mounting section 17 by a pair of ejection rollers (not shown).

2, a cap unit 51 provided in a capping device described later and a wiper carriage 41 are arranged around the liquid ejection head 21 provided in the recording unit 20 on the opposite side to the side on which the head unit 24 is located with respect to the transport path 19. The head unit 24 includes the liquid ejection head 21 and a support unit 25 that holds the liquid ejection head 21.

The liquid ejection head 21 is configured to eject liquid from multiple nozzles 22 constituting multiple nozzle groups, while extending in the width direction X, onto the medium M. When the liquid ejection head 21 ejects liquid onto the medium M, the direction in which the liquid is ejected is referred to as the ejection direction Y1. In addition, when the liquid ejection head 21 ejects liquid onto the medium M, the direction in which the medium M is transported is referred to as the first transport direction Z1.

In this embodiment, the nozzle surface 23 on which the nozzles 22 are arranged is not horizontal, but has a first predetermined angle θ1 with respect to the horizontal. That is, in this embodiment, the liquid ejection head 21 is arranged in a state in which the nozzle surface 23 has the first predetermined angle θ1 with respect to the horizontal, and in this state, the liquid ejection head 21 ejects liquid onto the medium M. Note that the nozzle surface 23 on which the nozzles 22 are arranged may also be arranged horizontally. That is, the liquid ejection head 21 may be arranged in a state in which the nozzle surface 23 is horizontal.

The liquid ejection head 21 of this embodiment is a line head having a number of nozzles 22 capable of simultaneously ejecting liquid across the entire width of the medium M in the width direction X that intersects with the first transport direction Z1 and the ejection direction Y1. The liquid ejection device 11 performs line printing by ejecting liquid toward the medium M, which is transported at a constant speed, from multiple nozzles 22 positioned opposite the entire width of the medium M.

In the liquid ejection device 11, maintenance operations such as capping, cleaning, flushing, and wiping are performed to prevent or resolve ejection problems caused by clogging of the nozzles 22 of the liquid ejection head 21 or adhesion of foreign matter.

Capping refers to the operation of the cap unit 51 contacting the nozzle surface 23 of the liquid ejection head 21 so as to surround the nozzle 22 when the liquid ejection head 21 is not ejecting liquid. Capping suppresses the thickening of the liquid inside the nozzle 22, thereby preventing ejection defects.

Cleaning refers to the operation of applying pressure to the upstream side of the liquid ejection head 21 to forcibly eject liquid from the nozzle 22, or applying suction force to the nozzle 22 of the liquid ejection head 21 to forcibly eject liquid from the nozzle 22.

Flushing refers to a discharge operation for discharging droplets unrelated to printing from the nozzle 22. Flushing is also called blank discharge. Flushing discharges viscous ink, air bubbles, or foreign matter that can cause discharge defects from the nozzle 22, thereby preventing clogging of the nozzle 22. Liquid discharged from the liquid discharge head 21 that is not used for printing is called waste liquid. Liquid discharged by flushing is waste liquid because it is not used for printing. The waste liquid discharged by flushing is received by the cap unit 51. That is, flushing is performed by the liquid discharge head 21 discharging droplets from the nozzle 22 into the cap unit 51.

Wiping refers to the action of wiping the nozzle surface 23 with a rubber wiper, cloth wiper, or the like. Wiping removes liquid and dirt such as dust adhering to the nozzle surface 23 of the liquid ejection head 21. Note that the liquid wiped off by wiping is also waste liquid, as it is not used for printing.

The position of the head unit 24 when the liquid ejection head 21 ejects liquid onto the medium M, i.e., when the liquid ejection head 21 records on the medium M, is referred to as the recording position. The position of the cap unit 51 when the liquid ejection head 21 ejects liquid onto the medium M is referred to as the retracted position. The position of the head unit 24 when the liquid ejection device 11 performs a maintenance operation is referred to as the maintenance position. The position of the cap unit 51 when the liquid ejection device 11 performs a maintenance operation is also referred to as the maintenance position.

As shown in FIG. 2, the head unit 24 is moved by a head movement mechanism (not shown) between a recording position indicated by a solid line in FIG. 2 and a maintenance position indicated by a two-dot chain line in FIG. 2. The direction in which the head unit 24 moves from the recording position to the maintenance position is called the first direction D1. The direction in which the head unit 24 moves from the maintenance position to the recording position is called the second direction D2.

The cap unit 51 is moved by a cap moving mechanism (not shown) between a retracted position shown by a solid line in FIG. 2 and a maintenance position shown by a two-dot chain line in FIG. 2. The direction in which the cap unit 51 moves from the recording position to the maintenance position is called the third direction D3. The direction in which the cap unit 51 moves from the maintenance position to the recording position is called the fourth direction D4.

2, the cap unit 51 moves in the third direction D3 from the retracted position shown by the solid line in FIG. 2 to the maintenance position shown by the two-dot chain line in FIG. 2, and then the head unit 24 moves in the first direction D1 from the recording position shown by the solid line in FIG. 2 to the maintenance position shown by the two-dot chain line in FIG. 2. As a result, the head unit 24 is capped by the cap unit 51. In this embodiment, flushing is performed by having the liquid ejection head 21 eject droplets from the nozzles 22 into the cap unit 51 in this capped state. That is, in the liquid ejection device 11 of this embodiment, both capping and flushing are performed at the maintenance position. Flushing may be performed in a state where the liquid ejection head 21 is away from the cap unit 51.

When maintenance is completed, the head unit 24 moves in the second direction D2 from the maintenance position shown by the two-dot chain line in FIG. 2 to the recording position shown by the solid line in FIG. 2. After that, the cap unit 51 moves in the fourth direction D4 from the maintenance position shown by the two-dot chain line in FIG. 2 to the retracted position shown by the solid line in FIG. 2. At this time, the wiper carriage 41 is positioned so as not to overlap the head unit 24 and the cap unit 51 in the width direction X. The movement of the wiper carriage 41 will be described later.

<Configuration of Liquid Ejection Head and Cap Unit>
As shown in Fig. 3, the liquid ejection head 21 includes a plurality of unit ejection heads 21a. On the surface of the support portion 25 facing the transport path 19 shown in Fig. 2, the plurality of unit ejection heads 21a are arranged at a first predetermined pitch P1 in the width direction X. The unit ejection heads 21a are composed of a plurality of nozzle rows 21b. The plurality of unit ejection heads 21a are arranged in a state inclined by a second predetermined angle θ2 with respect to the first transport direction Z1 in which the medium M is transported. In other words, the nozzle rows 21b are also arranged in a state inclined by the second predetermined angle θ2 with respect to the first transport direction Z1. In this embodiment, the liquid ejection head 21 includes five unit ejection heads 21a, and each unit ejection head 21a is composed of six nozzle rows 21b.

In this embodiment, the cap unit 51 has a plurality of unit caps 51a and a holder 59 that holds the plurality of unit caps 51a. The unit caps 51a are an example of a cap. The plurality of unit caps 51a are arranged at a first predetermined pitch P1 in the width direction X on the side opposite to the side on which the head unit 24 is located with respect to the transport path 19 shown in FIG. 2. The plurality of unit caps 51a are arranged in a state inclined by a second predetermined angle θ2 with respect to a first transport direction Z1 in which the medium M is transported. In other words, the unit caps 51a are arranged in a state in which the unit caps 51a are inclined by a second predetermined angle θ2 with respect to a first transport direction Z1 in which the medium M is transported.
When viewed from the direction along 1, the cap unit 51 has a substantially parallelogram shape. In this embodiment, the cap unit 51 includes five unit caps 51a.

One unit cap 51a is disposed at an opposing position for each unit ejection head 21a. Therefore, when the head unit 24 is capped by the cap unit 51, each of the multiple unit ejection heads 21a is covered by a separate unit cap 51a. That is, the multiple nozzles 22 of the liquid ejection head 21 are covered for each unit ejection head 21a by the same number of unit caps 51a as the unit ejection heads 21a. In this embodiment, the multiple nozzles 22 of the liquid ejection head 21 composed of five unit ejection heads 21a are covered for each unit ejection head 21a by the five unit caps 51a of the cap unit 51. As a result, all of the nozzles 22 of the liquid ejection head 21 are covered by the cap unit 51 during capping.

As shown in FIG. 4, the head unit 24 is moved by a head moving mechanism (not shown) between a recording position indicated by a solid line in FIG. 4 and a maintenance position indicated by a two-dot chain line in FIG.
The wiper carriage 41 is reciprocated between a retracted position shown by a solid line in Fig. 4 and a turned-back position shown by a two-dot chain line in Fig. 4 by a wiper movement mechanism (not shown). The direction in which the wiper carriage 41 moves from the retracted position to the turned-back position is referred to as a fifth direction D5. The direction in which the wiper carriage 41 moves from the turned-back position to the retracted position is referred to as a sixth direction D6.

As shown in FIG. 4, the head unit 24 moves in the first direction D1 from the recording position shown by the solid line in FIG. 4 to the maintenance position shown by the two-dot chain line in FIG. 4, and then the wiper carriage 41 moves in the fifth direction D5 from the retracted position shown by the solid line in FIG. 4 to the turn-back position shown by the two-dot chain line in FIG. 4. As a result, the nozzle surface 23 of the head unit 24 is wiped by the wiper member 42 of the wiper carriage 41.

When wiping is completed, the head unit 24 moves in the second direction D2 from the maintenance position shown by the two-dot chain line in FIG. 4, and is positioned at the recording position shown by the solid line in FIG. 4. After that, the wiper carriage 41 moves in the sixth direction D6 from the turn-back position shown by the two-dot chain line in FIG. 4, and is positioned at the retracted position shown by the solid line in FIG. 4.

<About the composition of the cap>
As shown in Fig. 5, a unit cap 51a, which is an example of a cap, includes a restricting member 52, an absorber 53, a first moisture permeable membrane 54, which is an example of a partition wall, a humidification chamber 55, and a case 56. The unit cap 51a has a low rectangular column shape with a substantially parallelogram-shaped bottom. In this embodiment, the unit cap 51a is used with the bottom of the parallelogram disposed on the XZ1 plane shown in Fig. 2. That is, the unit cap 51a shown in Fig. 5 is used with the bottom of the parallelogram inclined with respect to the horizontal. The XZ1 plane is a plane parallel to the nozzle surface 23 of the liquid ejection head 21 shown in Fig. 4.

The regulating member 52 has a generally parallelogram-shaped regulating surface 52a for regulating the position of the -Y1 direction side of the surface 53a of the absorber 53, and a positioning engaged portion 52c. The material used for the regulating member 52 is, for example, a thin metal plate such as stainless steel. The regulating member 52 ensures the flatness and strength of the regulating surface 52a by bending the four sides around the regulating surface 52a toward the +Y1 direction, thereby regulating the position of the absorber 53.

The restricting member 52 has a restricting surface 52a formed in a mesh pattern. That is, the restricting surface 52a has a plurality of communication holes 52b. The -Y1 direction side and the +Y1 direction side of the restricting surface 52a are in communication with each other via the plurality of communication holes 52b. This allows the unit cap 51a to allow liquid to pass from the -Y1 direction side to the +Y1 direction side of the restricting surface 52a and from the +Y1 direction side to the -Y1 direction side within the unit cap 51a.

As shown in FIG. 5, the absorbent body 53 is formed in the shape of a thin plate having a substantially parallelogram shape extending in the XZ1 plane. The absorbent body 53 is configured to be capable of absorbing liquid. Therefore, when the absorbent body 53 absorbs liquid, it may displace so that its volume increases, i.e., it may swell.

The restricting member 52 restricts the absorbent 53 at a predetermined position so as to widely expose the surface 53a of the absorbent 53 while keeping the distance between the surface 53a and the nozzle surface 23 shown in FIG. 4 constant. In other words, the restricting member 52 restricts the absorbent 53 from being displaced in the -Y1 direction when the absorbent 53 swells.

As shown in FIG. 5, the first moisture permeable membrane 54 is formed in the shape of a sheet having a substantially parallelogram shape extending in the XZ1 plane. The first moisture permeable membrane 54 has gas permeability. That is, the first moisture permeable membrane 54 allows the passage of gas but restricts the passage of liquid. In this embodiment, the material used for the first moisture permeable membrane 54 is a material in which a fluororesin is coated on a fabric. The material used for the first moisture permeable membrane 54 may be any material that does not allow liquid to pass through but allows gas to pass through, and may be a film membrane or an elastomer membrane.

The first moisture permeable membrane 54 has communication parts 54a on three of the four sides of the approximate parallelogram. The first moisture permeable membrane 54 is configured such that liquid can pass from the -Y1 direction side to the +Y1 direction side and from the +Y1 direction side to the -Y1 direction side only in the vicinity of the three sides of the first moisture permeable membrane 54 by slightly cutting out the central parts of the three sides toward the inside of the approximate parallelogram. The first moisture permeable membrane 54 may also have a communication part 54a on the side of the approximate parallelogram that is closest to the +Z direction.

As described above, in this embodiment, the unit cap 51a shown in FIG. 5 is provided on the XZ1 plane, with the bottom surface of the approximate parallelogram inclined relative to the horizontal. Because gravity exerts a force that causes the liquid to flow vertically in the -Z direction, the liquid does not easily flow to the side closest to the +Z direction of the approximate parallelogram. Therefore, in this embodiment, the first moisture permeable membrane 54 does not have a communication portion 54a on the side closest to the +Z direction of the approximate parallelogram.

As shown in FIG. 5, the humidification chamber 55 has a bottom surface that is a substantial parallelogram extending in the XZ1 plane. The humidification chamber 55 has a groove 55c in the center of its bottom surface through which the humidification fluid described below flows. The humidification chamber 55 is formed by resin molding or the like. In other words, the material used for the humidification chamber 55 is a material that does not allow liquid to pass through. The groove 55c has a groove wall 55i. The end of the groove wall 55i on the -Y1 direction side and the first moisture permeable membrane 54 are sealed, for example, by welding or bonding. As a result, a chamber is formed by the groove 55c and the first moisture permeable membrane 54 of the humidification chamber 55.

The humidification chamber 55 has communication portions 55e on three of the four sides of the approximate parallelogram, and positioning engagement portions 55d on two of the four sides. The humidification chamber 55 is configured such that liquid can pass from the -Y1 side to the +Y1 side and from the +Y1 side to the -Y1 side of the humidification chamber 55 only near the three sides of the humidification chamber 55 by slightly cutting out multiple points on the three sides toward the inside of the approximate parallelogram. The humidification chamber 55 may also have a communication portion 55e on the side of the approximate parallelogram that is closest to the +Z side. The humidification chamber 55 is not connected to the communication portion 55e because the periphery of the humidification chamber 55 is sealed.

As described above, in this embodiment, the unit cap 51a shown in Figure 5 is used with the bottom surface of the approximate parallelogram inclined relative to the horizontal. Because gravity acts as a force that causes the liquid to flow vertically in the -Z direction, the liquid is less likely to flow to the side closest to the +Z direction of the approximate parallelogram. Therefore, in this embodiment, the humidification chamber 55 does not have a communication part 55e on the side closest to the +Z direction of the approximate parallelogram.

The humidification chamber 55 has a communication hole 55f that communicates with the space inside the case 56, located slightly toward the +X direction side of the center of the communication part 55e in the communication part 55e on the side closest to the -Z direction of the approximate parallelogram. This allows the liquid flowing due to gravity to flow more evenly and efficiently through the communication hole 55f.

The case 56 has an air communication hole 56a on the side of the approximate parallelogram closest to the +Z direction, slightly toward the -X direction from the center of that side. The humidification chamber 55 also has a communication hole 55j shown in FIG. 6 that connects the space inside the case 56 to the air communication hole 56a. This allows the space inside the case 56 to communicate with the atmosphere, which will be described later. In order to allow the air to circulate inside the case 56 more efficiently, it is desirable to position the air communication hole 56a in the center of the case 56. In this embodiment, the humidification chamber 55 has a bottom surface that is approximately a parallelogram. Therefore, the air communication hole 56a is located slightly toward the -X direction in the width direction X.

As shown in FIG. 6, the humidification chamber 55 has an inlet 55a, an outlet 55b, an engagement portion 55g, and a positioning engagement portion 55h on the +Y1 side of the bottom surface of the approximate parallelogram. The engagement portion 55g is tubular, with the inlet 55a formed inside the engagement portion 55g on the +X side and the outlet 55b formed inside the engagement portion 55g on the -X side. The inlet 55a and the outlet 55b communicate with the +Y1 side and -Y1 side of the bottom surface of the approximate parallelogram. The inlet 55a and the outlet 55b communicate with each other through a flow path formed by the groove 55c and the first moisture permeable membrane 54 inside the humidification chamber 55. The flow path formed by the groove 55c and the first moisture permeable membrane 54 will be described later.

The case 56 has an atmosphere communication hole 56a, a discharge hole 56b (an example of a hole), an engaged portion 56c, a positioning engaged portion 56d shown in FIG. 5, and a seal portion 56e. The atmosphere communication hole 56a and the discharge hole 56b communicate with the +Y1 side and the -Y1 side of the bottom surface of the approximate parallelogram.

The seal portion 56e is formed in a frame shape along the peripheral wall on the surface closest to the -Y1 direction of the peripheral wall forming the case 56. The material used for the seal portion 56e is, for example, a flexible material such as a rubber material or an elastomer. In order to prevent the liquid in the unit cap 51a from dripping from the seal portion 56e to the outside of the unit cap 51a, the material of the seal portion 56e may be a water-repellent elastomer material that repels the liquid ejected from the liquid ejection head 21. In this embodiment, the surface closest to the -Y1 direction of the peripheral wall forming the case 56 is located on the XZ1 plane inclined relative to the horizontal. The liquid moves vertically due to gravity. Therefore, the seal portion 56e below the center of the unit cap 51a in the vertical direction Z may be more water-repellent than the upper seal portion 56e, or only the lower seal portion 56e may be water-repellent.

The case 56 forms a low prismatic shape with a bottom surface of a substantially parallelogram of the unit cap 51a, and houses the restricting member 52, the absorbent 53, the first moisture permeable membrane 54, and the humidification chamber 55. The positioning engaging portion 55d of the humidification chamber 55 engages with the positioning engaged portion 52c of the restricting member 52. The engaging portion 55g of the humidification chamber 55 engages with the engaged portion 56c of the case 56. The positioning engaging portion 55h of the humidification chamber 55 engages with the positioning engaged portion 56d of the case 56 shown in FIG. 5. This allows the restricting member 52, the absorbent 53, the first moisture permeable membrane 54, and the humidification chamber 55 to be held in the case 56. Furthermore, the communication hole 55f of the humidification chamber 55 communicates with the exhaust hole 56b of the case 56. The communication hole 55j of the humidification chamber 55 and the atmosphere communication hole 56a of the case 56 are in communication with each other.

As shown in Figure 7, the groove 55c of the humidification chamber 55 is formed on the -Y1 side of the bottom surface of the approximate parallelogram. The groove 55c is formed in a meandering, maze-like shape, covering the entire surface, from the inlet 55a to the outlet 55b. The -Y1 side end of the groove wall 55i forming the groove 55c and the first moisture permeable membrane 54 shown in Figure 5 are sealed over the entire area from the inlet 55a to the outlet 55b. Therefore, the groove 55c and the first moisture permeable membrane 54 form a one-way, winding flow path with a complex, meandering route, connecting the inlet 55a and the outlet 55b. That is, the humidification chamber 55 is formed in the shape of a flow path that connects the inlet 55a and the outlet 55b by a groove 55c through which the humidification fluid described below flows and a first moisture permeable membrane 54 shown in FIG. 5, which is an example of a partition wall that covers the groove 55c.

As described below, since the space inside the unit cap 51a is humidified by the humidifying fluid flowing through the groove 55c, it is desirable that the area occupied by the groove 55c inside the unit cap 51a in the XZ1 plane be large. In other words, in order to increase the area occupied by the groove 55c relative to the bottom surface of the unit cap 51a, it is desirable to route the flow path around the entire bottom surface of the unit cap 51a.

<Regarding the recess that forms the space>
As shown in Fig. 8, the liquid ejection device 11 includes a capping device 50. The capping device 50 has a movable capping unit 51 shown in Fig. 3. The capping unit 51 has unit caps 51a.

When the cap unit 51 moves in the first direction D1 to the maintenance position shown in FIG. 8, and then the head unit 24 moves in the third direction D3 to the maintenance position shown in FIG. 8, the unit cap 51a of the cap device 50 comes into contact with the nozzle surface 23 of the liquid ejection head 21. The surface of the seal portion 56e located around the periphery of the case 56 on the -Y1 direction side is called the contact surface 56f. When the cap device 50 comes into contact with the liquid ejection head 21, the nozzle surface 23 and the contact surface 56f come into contact with each other, and the nozzle surface 23 is sealed by the seal portion 56e. In other words, the cap device 50 is configured to be able to form a space SP surrounding the opening 22a of the nozzle 22 when the unit cap 51a, which is an example of a cap, comes into contact with the liquid ejection head 21 having the nozzle 22 that ejects liquid. In other words, the unit cap 51a, which is an example of a cap, can form a space SP surrounding the opening 22a of the nozzle 22 when it comes into contact with a liquid ejection head 21 having a nozzle 22 that ejects liquid.

The unit cap 51a has a recess 57 that forms a space SP. In this embodiment, as shown in FIG. 8, the recess 57 is composed of the inner surface of the case 56, the outer surface of the humidification chamber 55, and the surface of the first moisture permeable membrane 54 on the absorber 53 side. The recess 57 has an absorber 53 that can absorb liquid at a position where it contacts the first moisture permeable membrane 54, which is an example of a partition. The first moisture permeable membrane 54, which has gas permeability, divides the recess 57 and the humidification chamber 55. As a result, when the cap device 50 and the liquid ejection head 21 come into contact with each other, the recess 57 forms a space SP that surrounds the opening 22a of the nozzle 22. The recess 57 has a volume that prevents the liquid ejected into the recess by flushing from overflowing from the seal portion 56e when flushing is performed.

In this embodiment, the nozzle surface 23 on which the nozzles 22 are arranged is not horizontal, but has a first predetermined angle θ1 with respect to the horizontal. Therefore, the surface on the -Y1 direction side of the seal portion 56e located around the periphery of the case 56 is also not horizontal, but has a first predetermined angle θ1 with respect to the horizontal. As a result, when the unit cap 51a is inclined at the first predetermined angle θ1 with respect to the horizontal, the nozzle surface 2
3 and the contact surface 56f of the seal portion 56e come into close contact with each other, and the nozzle surface 23 is sealed by the seal portion 56e. Even in this embodiment in which the unit cap 51a is inclined relative to the horizontal, the recess 57 has a volume that prevents the liquid ejected into the recess by flushing from spilling out from the lower part of the inclined seal portion 56e when flushing is performed.

The nozzle surface 23 on which the nozzles 22 are arranged and the surface on the -Y1 direction side of the seal portion 56e may be arranged horizontally. In other words, the nozzle surface 23 may be sealed by the seal portion 56e with the liquid ejection head 21 and the unit cap 51a arranged horizontally.

As shown in FIG. 9, the regulating member 52 and the absorbent 53 are liquid permeable, and the first moisture permeable membrane 54 is not liquid permeable. Therefore, during flushing, the liquid discharged from the nozzle 22 passes through the regulating member 52 and the absorbent 53 from the -Y1 direction side to the +Y1 direction side, but does not pass through the first moisture permeable membrane 54 from the -Y1 direction side to the +Y1 direction side. The liquid is also absorbed by the absorbent 53. The liquid absorbed by the absorbent 53 spreads throughout the absorbent 53. More specifically, when there are parts in the absorbent 53 where less liquid has been absorbed around a part where a lot of liquid has been absorbed, the liquid flows from the part where more liquid has been absorbed to the part where less liquid has been absorbed.

When the absorber 53 absorbs more liquid and approaches a state where it cannot absorb any more liquid, the liquid in the absorber 53 flows in the vertical direction, −Z direction, due to gravity. As a result, when the liquid reaches the surface of the first moisture permeable membrane 54 on the −Y1 side, it flows in the −Z1 direction due to gravity. Since the first moisture permeable membrane 54 does not have liquid permeability, the first moisture permeable membrane 54 restricts the passage of the liquid. In other words, the liquid does not flow into the humidification chamber 55. Then, the liquid passes through the communication portion 54a and the communication portion 55e due to gravity, and is discharged outside the unit cap 51a through the discharge hole 56b of the case 56. In other words, the recess 57 has the discharge hole 56b, which is an example of a hole that can discharge the liquid discharged from the liquid ejection head 21 into the unit cap 51a.

In this embodiment, the exhaust hole 56b, which is an example of a hole, is provided in the recess 57 at a lower position than the first moisture permeable membrane 54, which is an example of a partition wall. That is, the exhaust hole 56b is provided on the -Z direction side of the first moisture permeable membrane 54. The exhaust hole 56b, which is an example of a hole, may also be provided at the bottom of the recess 57. That is, the exhaust hole 56b may be provided on the furthest side of the recess 57 in the -Z direction.

The humidification chamber 55 has an inlet 55a through which the humidification fluid described below flows in to humidify the space SP, and an outlet 55b through which the humidification fluid flows out. Since the first moisture permeable membrane 54 does not have liquid permeability, the first moisture permeable membrane 54 restricts the passage of liquid in the humidification chamber 55 from the +Y1 direction side to the -Y1 direction side. As a result, in the humidification chamber 55, the liquid that flows in from the inlet 55a flows out from the outlet 55b. The humidification chamber 55 is provided in an inclined position relative to the horizontal. The inlet 55a and the outlet 55b are provided above the center of the humidification chamber 55 in the vertical direction Z. In this embodiment, the inlet 55a and the outlet 55b are located on the +Z direction side of the center of the humidification chamber 55 in the vertical direction Z. By providing the inlet 55a and the outlet 55b on the +Z direction side of the humidification chamber 55, it is possible to prevent the liquid in the humidification chamber 55 from flowing out of the humidification chamber 55 from the inlet 55a or the outlet 55b due to head pressure.

10, the restricting member 52, the absorber 53, and the first moisture permeable membrane 54 are gas permeable. Therefore, the atmosphere and water vapor, which are gases, pass through the restricting member 52, the absorber 53, and the first moisture permeable membrane 54 from the -Y1 direction side to the +Y1 direction side, and from the +Y1 direction side to the -Y1 direction side. As a result, the cap device 50 is configured to allow water vapor evaporated from the humidifying fluid described below to flow from the humidifying chamber 55 into the recess 57 within the unit cap 51a.

The recess 57 has an air communication hole 56a for communicating the space SP with the atmosphere. The air communication hole 56a is provided above the vertical center of the unit cap 51a. In this embodiment, the air communication hole 56a is provided on the +Z direction side of the center of the vertical direction Z of the recess 57. By providing the air communication hole 56a above the vertical center of the unit cap 51a, it is possible to prevent the air communication hole 56a from being blocked by liquid. In addition, the air communication hole 56a may be provided at a position higher than the first moisture permeable film 54, i.e., on the +Z direction side of the first moisture permeable film 54.

<Configuration of the humidified fluid circulating mechanism included in the capping device>
As shown in FIG. 11, the capping device 50 includes a capping unit 51 having unit caps 51 a , a cap moving mechanism (not shown), a humidified fluid circulating mechanism 60 , and a waste liquid collecting mechanism 80 .

The humidified fluid circulation mechanism 60 of the cap device 50 includes a humidified fluid storage section 61 that stores humidified fluid L1a, a supply flow path 62a, and a recovery flow path 62b. The supply flow path 62a connects the humidified fluid storage section 61 to the inlet 55a. That is, the supply flow path 62a connects the humidified fluid storage section 61 to a unit cap 51a, which is an example of a cap. The recovery flow path 62b connects the outlet 55b to the humidified fluid storage section 61. That is, the recovery flow path 62b connects the unit cap 51a, which is an example of a cap, to the humidified fluid storage section 61. The humidified fluid circulation mechanism 60 includes a circulation path 62 that includes the humidified fluid storage section 61, the supply flow path 62a, and the recovery flow path 62b.

The humidifying fluid storage section 61 has an inflow section 61f and an outflow section 61g. The humidifying fluid storage section 61 communicates with the recovery flow path 62b at the inflow section 61f. The humidifying fluid storage section 61 communicates with the supply flow path 62a at the outflow section 61g.

In the humidified fluid circulation mechanism 60, the humidified fluid L1a flowing in the circulation path 62 is a fluid containing moisture for humidifying the space SP shown in FIG. 8. It is desirable that the moisturizing power of the humidified fluid L1a is equivalent to the moisturizing power of the liquid ejected from the liquid ejection head 21. The moisturizing power is the concentration of the moisturizing agent contained in the humidified fluid L1a or the liquid ejected from the liquid ejection head 21. For example, when the liquid ejection head 21 ejects ink, which is an example of a liquid, onto a medium such as paper to print, it is desirable that the moisturizing power of the humidified fluid L1a is equivalent to the moisturizing power of fresh ink. It is also desirable that the moisturizing power of the ink is balanced for each color. Details of the humidified fluid L1a will be described later.

As shown in FIG. 3, the cap unit 51 provided in the cap device 50 of this embodiment has five unit caps 51a shown in FIG. 6. That is, the cap device 50 is configured with a plurality of unit caps 51a, which are an example of a cap, lined up. In the cap device 50, each of the five unit caps 51a has an inlet 55a shown in FIG. 6 and an outlet 55b shown in FIG. 6. Therefore, in this embodiment, among the plurality of unit caps 51a, the outlet 55b of one unit cap 51a is connected to the inlet 55a of another unit cap 51a adjacent to the unit cap 51a. For example, the outlet 55b of one unit cap 51a and the inlet 55a of another unit cap 51a adjacent to the unit cap 51a are connected by a tube not shown, and the outlet 55b and the inlet 55a are connected to each other. As a result, the inlet 55a located at the most upstream position and the outlet 55b located at the most downstream position are connected to each other. The inlet 55a located most upstream is connected to the supply flow path 62a shown in Fig. 11. And the outlet 55b located most downstream is connected to the recovery flow path 62b shown in Fig. 11. That is, the capping device 50 of this embodiment is configured so that the humidifying fluid L1a flowing in the circulation path 62 shown in Fig. 11 can flow through the grooves 55c of the humidifying chambers 55 shown in Fig. 7 of all the unit caps 51a. When the capping device 50 has only one unit cap 51a, the inlet 55a of that unit cap 51a may be connected to the supply flow path 62a, and the outlet 55b of that unit cap 51a may be connected to the recovery flow path 62b.

As shown in FIG. 11, the humidifying fluid storage unit 61 stores a humidifying fluid L1a that contains moisture for humidifying the space SP shown in FIG. 8. The humidifying fluid storage unit 61 has a detection unit 61a that detects the liquid level in the humidifying fluid storage unit 61. The detection unit 61a has a first electrode 61b and a second electrode 61c.

The humidifying fluid L1a contains a conductive additive. The detection unit 61a detects the liquid level in the humidifying fluid storage unit 61 by the electrical resistance between the first electrode 61b and the second electrode 61c. When the liquid level of the humidifying fluid L1a stored in the humidifying fluid storage unit 61 is higher than a first predetermined height H1, which is an example of a "predetermined height", the first electrode 61b and the second electrode 61c are electrically connected. When the liquid level of the humidifying fluid L1a stored in the humidifying fluid storage unit 61 is lower than the first predetermined height H1 and higher than the second predetermined height H2, the first electrode 61b and the second electrode 61c are not electrically connected. In this way, the detection unit 61a is configured to be able to determine whether the liquid level of the humidifying fluid L1a is higher than the first predetermined height H1 by changing the output level when the first electrode 61b is in contact with the liquid level and when it is not in contact with the liquid level.

When the detection unit 61a detects that the liquid level of the humidifying fluid L1a is above the first predetermined level H1, this means that the humidifying fluid L1a is sufficiently contained in the humidifying fluid storage unit 61, that is, the humidifying fluid storage unit 61 is full of the humidifying fluid L1a. In this embodiment, the full state of the humidifying fluid storage unit 61 is detected. Instead of only detecting the full state of the humidifying fluid storage unit 61, the empty or nearly empty state of the humidifying fluid storage unit 61 may be detected. In addition, the method for detecting the liquid level is not limited to the electrode method, and may be an optical method or a capacitance method.

The humidifying fluid storage section 61 has a second atmosphere communication passage 61d and a second moisture permeable membrane 61e. The second atmosphere communication passage 61d connects the humidifying fluid storage section 61 to the atmosphere. The second atmosphere communication passage 61d may have a labyrinth-like thin tube structure. A labyrinth-like thin tube structure refers to a tube structure having a complex path that is narrow and meandering to the extent that air can flow in and out, but the flow of liquid in and out is significantly restricted. The labyrinth-like thin tube structure suppresses evaporation of the liquid in the humidifying fluid storage section 61.

The second moisture permeable membrane 61e is provided at the connection between the humidified fluid storage section 61 and the second atmosphere communication passage 61d. The second moisture permeable membrane 61e allows gas to pass from the humidified fluid storage section 61 to the second atmosphere communication passage 61d, while restricting the passage of liquid from the humidified fluid storage section 61 to the second atmosphere communication passage 61d. To increase the efficiency of gas passing from the humidified fluid storage section 61 to the second atmosphere communication passage 61d, it is desirable for the area of the second moisture permeable membrane 61e to be large.

As shown in FIG. 11, the humidified fluid circulation mechanism 60 provided in the cap device 50 includes a first pump 63, which is an example of a pump capable of flowing humidified fluid L1a in the circulation path 62, a first check valve 64, and a pressure adjustment valve 65. The first pump 63 causes the fluid to flow in the circulation path 62. When the first pump 63 is driven, the liquid flowing through the supply flow path 62a is sent to the humidification chamber 55 in the unit cap 51a.

The first check valve 64 allows the flow of liquid from the humidifying fluid storage section 61 side to the unit cap 51a side, and prevents the liquid from flowing back from the unit cap 51a side to the humidifying fluid storage section 61 side due to a head difference. An on-off valve may be provided instead of the first check valve 64. When the on-off valve is opened, the liquid may flow from the humidifying fluid storage section 61 side to the unit cap 51a side by driving the first pump 63. Opening the on-off valve is referred to as opening the valve or opening the valve. Closing the on-off valve is referred to as closing the valve or closing the valve.

The pressure adjustment valve 65 allows liquid to flow from the unit cap 51a side to the humidifying fluid storage section 61 side when the humidifying fluid storage section 61 side reaches a predetermined negative pressure, and always prevents liquid from flowing back from the humidifying fluid storage section 61 side to the unit cap 51a side. The pressure difference of the head difference is adjusted by the pressure adjustment valve 65 so that liquid does not flow from the unit cap 51a side to the humidifying fluid storage section 61 side due to head pressure.

As shown in FIG. 11, the humidified fluid circulation mechanism 60 provided in the capping device 50 includes a moisture supply unit 66 capable of supplying moisture L1b into the circulation path 62. The moisture supply unit 66 includes a moisture storage unit 66a, a moisture supply flow path 66b, a first on-off valve 66c which is an example of an on-off valve, and a second check valve 66d. The moisture storage unit 66a stores moisture L1b that can be supplied into the circulation path 62. The moisture supply flow path 66b communicates with the circulation path 62. The first on-off valve 66c is configured to be able to open and close the moisture supply flow path 66b.

The moisture storage section 66a has an outlet section 66f. The moisture storage section 66a communicates with the moisture supply flow path 66b at the outlet section 61g. The moisture supply flow path 66b communicates with the circulation path 62 at the first junction 62c of the circulation path 62. In other words, the moisture storage section 66a communicates with the circulation path 62. It is preferable that the moisture storage section 66a is configured to be replaceable.

The moisture L1b supplied from the moisture storage section 66a to the circulation path 62 is moisture to replenish the moisture evaporated from the humidification fluid L1a. The moisture L1b is composed of pure water and a small amount of preservative.

When the first on-off valve 66c is opened, the water storage section 66a and the circulation path 62 are connected by the water supply flow path 66b. The second check valve 66d allows the flow of liquid from the water storage section 66a to the circulation path 62, and prevents the backflow of liquid from the circulation path 62 to the water storage section 66a due to the head difference. The second check valve 66d is not necessary. When the second check valve 66d is not necessary, the first pump 63 may cause the water L1b to flow from the water storage section 66a to the unit cap 51a by driving the first pump 63 when the first on-off valve 66c is opened.

As shown in FIG. 11, the humidified fluid circulation mechanism 60 provided in the cap device 50 further includes a pressurized air supply unit 67. The pressurized air supply unit 67 is configured to be able to supply pressurized air into the circulation path 62. The pressurized air supply unit 67 includes a pressurized air supply path 67a that communicates with the circulation path 62, a second on-off valve 67b, and a second pump 67c. When the second on-off valve 67b is opened, the second pump 67c communicates with the circulation path 62 via the pressurized air supply path 67a. The second pump 67c is, for example, a pressure pump. The second pump 67c applies pressure to the atmosphere to produce pressurized air, and supplies the pressurized air to the pressurized air supply path 67a.

In the circulation path 62, instead of providing the pressurized air supply unit 67 downstream of the first pump 63, an atmosphere supply unit may be provided upstream of the first pump 63 and downstream of the first junction 62c. The atmosphere supply unit may have an atmosphere communication passage communicating with the atmosphere and an on-off valve. Then, the atmosphere may be sent to the circulation path 62 by the first pump 63 in a state in which the circulation path 62 and the atmosphere are communicated through the atmosphere communication passage by opening the on-off valve. That is, the capping device 50 may have an atmosphere supply unit that supplies atmosphere to the circulation path 62 between the first junction 62c where the moisture supply unit 66 and the circulation path 62 join and the inlet 55a of the unit cap 51a in the circulation path 62 through which the humidifying fluid L1a flows. The capping device 50 may further have a pump that sends the atmosphere to the circulation path 62.

<Configuration of waste liquid recovery mechanism provided in capping device>
As shown in FIG. 11 , the waste liquid recovery mechanism 80 provided in the capping device 50 has a waste liquid recovery path 81 , a third pump 82 , a buffer chamber 83 , a fourth pump 84 , a third atmosphere communication passage 85 , and a waste liquid storage section 86 .

The waste liquid recovery path 81 includes a first waste liquid recovery path 81a and a second waste liquid recovery path 81b. The first waste liquid recovery path 81a communicates with the space SP formed by the recess 57 shown in FIG. 8 in the unit cap 51a at the discharge hole 56b of the unit cap 51a. The first waste liquid recovery path 81a communicates with the space SP and the waste liquid storage section 86 through the buffer chamber 83. The second waste liquid recovery path 81b communicates with the wiper carriage 41 at the waste liquid outlet 43 of the wiper carriage 41. The second waste liquid recovery path 81b communicates with the wiper carriage 41 and the waste liquid storage section 86.

During flushing, cleaning, etc., liquid is discharged from the nozzles 22 of the liquid ejection head 21 as waste liquid L2. The waste liquid L2, which is an example of a liquid, is collected from within the unit cap 51a and flows into the first waste liquid recovery path 81a. During wiping, liquid adhering to the nozzle surface 23 of the liquid ejection head 21 is wiped away and collected into the wiper carriage 41 as waste liquid L2. The waste liquid L2 is collected from within the wiper carriage 41 and flows into the second waste liquid recovery path 81b. The waste liquid L2 collected by flushing or cleaning and the waste liquid L2 collected by wiping are sent to the waste liquid storage section 86 by the third pump 82. The waste liquid L2 is then stored in the waste liquid storage section 86.

As shown in FIG. 3, the cap unit 51 provided in the cap device 50 of this embodiment has five unit caps 51a shown in FIG. 6. That is, the cap device 50 is configured with a plurality of unit caps 51a lined up, and each of the five unit caps 51a has a discharge hole 56b. Therefore, in this embodiment, the five discharge holes 56b are connected to the first waste liquid recovery path 81a, and the first waste liquid recovery path 81a connects the five discharge holes 56b to the waste liquid storage section 86. When the cap device 50 has only one unit cap 51a, only the discharge hole 56b of that unit cap 51a may be connected to the first waste liquid recovery path 81a.

As shown in FIG. 11, in this embodiment, the fourth pump 84 is a pressure reducing pump. The fourth pump 84 lowers the air pressure in the buffer chamber 83 by discharging the air in the buffer chamber 83 to the outside of the buffer chamber 83 through the third atmosphere communication passage 85. This makes it easier for the waste liquid L2 discharged from the nozzle 22 of the liquid ejection head 21 into the unit cap 51a during flushing or cleaning to flow into the buffer chamber 83 through the first waste liquid recovery passage 81a. Note that the buffer chamber 83, the fourth pump 84, and the third atmosphere communication passage 85 may not be required.

As shown in FIG. 11, the cap unit 51 having the unit cap 51a has an atmosphere opening mechanism 58. The atmosphere opening mechanism 58 has a first atmosphere communication passage 58a and a third opening/closing valve 58b.

The first atmosphere communication passage 58a communicates the atmosphere communication holes 56a of the unit caps 51a in the cap unit 51 with the atmosphere. The third on-off valve 58b is an on-off valve capable of opening and closing the first atmosphere communication passage 58a. In this embodiment, the atmosphere side of the first atmosphere communication passage 58a is opened. The cap device 50 is configured such that when the cap unit 51 moves from the maintenance position shown by the two-dot chain line in FIG. 11 in the fourth direction D4 to the retracted position shown by the solid line in FIG. 11, the open part hits a wall (not shown) and the wall closes the first atmosphere communication passage 58a. That is, the third on-off valve 58b is opened and closed by the movement of the cap unit 51. During flushing or cleaning, the first atmosphere communication passage 58a is in an open state and the liquid ejection head 21 discharges liquid into the unit cap 51a.

<Electrical Configuration of the Liquid Ejection Device>
12, the liquid ejection device 11 includes a control unit 90 that controls the head unit 24, the wiper device 40, and the capping device 50. The capping device 50 includes a detector group 91 controlled by the control unit 90. The detector group 91 includes a detector 61a that detects the liquid level in the humidifying fluid storage unit 61. The detector 61a outputs the detection result to the control unit 90.

The control unit 90 has an interface unit 94, a CPU 95, a memory 96, a control circuit 97, and a drive circuit 98. The interface unit 94 transmits and receives data between an external device, a computer 99, and the liquid ejection device 11. The drive circuit 98 generates a drive signal that drives the actuator of the liquid ejection head 21.

The CPU 95 is an arithmetic processing device. The memory 96 is a storage device that secures an area for storing the programs of the CPU 95 or a working area, and has memory elements such as RAM and EEPROM. The CPU 95 controls the head unit 24, the wiper device 40, the cap device 50, etc. via the control circuit 97 in accordance with the programs stored in the memory 96.

<About the circulation of humidified fluid>
The circulation operation in the maintenance method of the capping device will now be described.
As shown in Fig. 13, the capping device 50 performs a circulation operation. During the circulation operation, the first on-off valve 66c is closed, and the control unit 90 causes the humidified fluid circulation mechanism 60 to flow the humidified fluid L1a in the circulation path 62 in the direction of the solid arrow shown in Fig. 13. The control unit 90 then checks the amount of water evaporated from the humidified fluid L1a.

The circulation path is made up of a humidifying fluid storage section 61 that stores humidifying fluid L1a containing moisture for humidifying the space SP shown in FIG. 8, a supply flow path 62a that connects the humidifying fluid storage section 61 to the unit cap 51a, a recovery flow path 62b that connects the unit cap 51a to the humidifying fluid storage section 61, and the humidifying chamber 55 shown in FIG. 8 in the unit cap 51a. Note that it is desirable that the internal pressure in the unit cap 51a during circulation operation be set to below the meniscus withstand pressure of the liquid ejection head 21 by adjusting the circulation flow rate by the first pump 63.

As shown in FIG. 13, in the circulation operation of the humidified fluid L1a, the humidified fluid L1a flows through the circulation path 62 in the direction of the solid arrow shown in FIG. 13, and circulates through the circulation path. The control unit 90 causes the humidified fluid L1a to flow through the circulation path 62, so that the humidified fluid L1a flows through a single, winding flow path having a complex, serpentine path shown in FIG. 7 within the humidification chamber 55. Moisture from the humidified fluid L1a mainly evaporates in the humidification chamber 55 within the unit cap 51a. Then, for example, when the humidified fluid L1a in the humidification chamber 55 flows into the humidified fluid storage unit 61 and the humidified fluid L1a in the humidification fluid storage unit 61 flows into the humidification chamber 55, the control unit 90 stops the flow of the humidified fluid L1a and checks the amount of moisture evaporated from the humidified fluid L1a. In other words, the purpose of the circulation operation in the maintenance method for the cap device includes checking the amount of water evaporation from the humidification fluid L1a.

13, the control unit 90 manages time using a timer or the like, and periodically executes the circulation operation. For example, when the power supply of the liquid ejection device 11 is turned on, the control unit 90 executes the circulation operation once a day. At the end of the flow of the circulation operation described later, the control unit 90
In order to confirm the amount of water evaporation from the humidifying fluid L1a, information on the liquid level in the humidifying fluid storage section 61 is acquired from the detection section 61a. If the amount of water evaporation in the unit cap 51a is large, the liquid level in the humidifying fluid storage section 61 will be low. The amount of water evaporation increases during the time when the unit cap 51a is located at the retracted position shown in FIG. 13, that is, during the time when the unit cap 51a does not form the space SP surrounding the opening 22a of the nozzle 22 shown in FIG. 8. Therefore, the control section 90 may perform the circulation operation by managing the time when the unit cap 51a is located at the retracted position for each temperature and humidity environment. In addition, the control section 90 may also perform the circulation operation before recording on the medium M for the first time after the liquid ejection device 11 is installed, before recording on the medium M for the first time after the cap unit 51 is replaced with a new cap unit 51, or before recording on the medium M for the first time after the moisture storage section 66a is replaced with a full moisture storage section 66a.

To reduce the frequency of the circulation operation, it is desirable for the humidifying fluid storage section 61 to have a large liquid surface area relative to the depth within the humidifying fluid storage section 61. This makes it possible to reduce the change in the height of the liquid surface when the amount of liquid within the humidifying fluid storage section 61 changes due to the evaporation of moisture contained in the humidifying fluid L1a. Also, in order to make the change in concentration of the humidifying fluid L1a caused by the evaporation of moisture contained in the humidifying fluid L1a from the humidifying fluid L1a as gradual as possible, it is desirable to make the volume of the humidifying fluid storage section 61 as large as possible within the size of the liquid ejection device 11.

Next, referring to the flowchart shown in FIG. 14, the flow of the circulation operation in the maintenance method for the capping device will be described in order, with the control performed by the control unit 90 in each step.

In step S101, the control unit 90 determines whether the first on-off valve 66c is in a closed state. If the first on-off valve 66c is in a closed state, the process proceeds to step S103. If the first on-off valve 66c is in an open state, the process proceeds to step S102. Then, in step S102, the control unit 90 closes the first on-off valve 66c.

In step S103, the control unit 90 drives the first pump 63 for a first predetermined time T1 with the first on-off valve 66c in a closed state. As a result, as shown in FIG. 13, the humidification fluid L1a flows in the circulation path 62 in the direction of the solid arrow shown in FIG. 13.

In step S104, the control unit 90 stops the first pump 63 for a second predetermined time T2 with the first on-off valve 66c in a closed state. This stabilizes the liquid level state in the humidifying fluid storage unit 61. Note that in order to shorten the time until the liquid level state stabilizes, it is desirable to reduce the amount of change in the liquid level height when the amount of liquid in the humidifying fluid storage unit 61 changes by increasing the area of the liquid level relative to the depth in the humidifying fluid storage unit 61.

In step S105, the control unit 90 acquires information on the liquid level in the humidifying fluid storage unit 61 from the detection unit 61a. Then, in step S106, the control unit 90 determines whether the liquid level is higher than the first predetermined height H1. If the liquid level is higher than the first predetermined height H1, the flow ends.

When the liquid level is lower than the first predetermined height H1, the process proceeds to step S200. In step S200, the control unit 90 executes a subroutine for the concentration adjustment operation, which will be described later. When the subroutine for the concentration adjustment operation is completed, the control unit 90 ends the flow.

<Humidification fluid concentration adjustment operation>
The concentration adjustment operation in the maintenance method of the capping device will be described.
As shown in Fig. 15, the capping device 50 performs a concentration adjustment operation. During the concentration adjustment operation, the first on-off valve 66c is open, and the control unit 90 causes the humidified fluid circulation mechanism 60 to flow the humidified fluid L1a in the circulation path 62 in the direction of the solid arrow shown in Fig. 15. At this time, because the first on-off valve 66c is open, the moisture L1b in the moisture supply unit 66 flows in the direction of the dashed arrow shown in Fig. 15 and is supplied into the circulation path 62. In other words, the concentration adjustment operation in the maintenance method for the capping device includes supplying the moisture L1b into the circulation path 62 by the moisture supply unit 66 and flowing the humidified fluid L1a in the circulation path 62.

The concentration adjustment operation is executed by the control unit 90 at the end of the flow of the circulation operation described above, when the liquid level in the humidifying fluid storage unit 61 is detected by the detection unit 61a to be below a first predetermined height H1, which is an example of a "predetermined height", when the control unit 90 acquires information on the liquid level in the humidifying fluid storage unit 61. That is, when the concentration adjustment operation is performed when the detection unit 61a detects that the liquid level in the humidifying fluid storage unit 61 is below a predetermined height, the capping device 50 supplies moisture L1b in the moisture storage unit 66a into the circulation path 62 until the liquid level is detected to be equal to or above the predetermined height. Then, the humidifying fluid L1a is caused to flow in the circulation path 62.

Moisture evaporates from the humidifying fluid L1a in the unit cap 51a, and the humidifying fluid L1a circulates in the circulation path 62 by the circulation operation described above. As a result, the moisture in the humidifying fluid storage section 61 also decreases, so the liquid level in the humidifying fluid storage section 61 decreases. As the evaporation progresses further, the liquid level in the humidifying fluid storage section 61 becomes lower than the first predetermined height H1. The first predetermined height H1 is set so that the concentration of the humidifying fluid L1a at this time is higher than the predetermined concentration. The control section 90 executes a concentration adjustment operation, and moisture L1b in the moisture storage section 66a is supplied to the circulation path 62 so that the liquid level is higher than the first predetermined height H1. As a result, approximately the same amount of moisture as that evaporated in the unit cap 51a is supplied to the circulation path 62, and the concentration of the humidifying fluid L1a becomes lower than the predetermined concentration. In other words, the concentration of the humidification fluid L1a returns to the concentration of the humidification fluid L1a before the water evaporated in the unit cap 51a.

In the concentration adjustment operation, the control unit 90 opens the first on-off valve 66c and supplies the moisture L1b in the moisture storage unit 66a into the circulation path 62. When the control unit 90 determines that the liquid level in the humidifying fluid storage unit 61 is higher than the first predetermined height H1, the control unit 90 closes the first on-off valve 66c and performs the above-mentioned circulation operation to cause the humidifying fluid L1a in the humidifying fluid storage unit 61 to flow in the circulation path 62. In other words, the concentration adjustment operation in the maintenance method for the cap device includes opening the first on-off valve 66c, which is an example of an on-off valve, when supplying the moisture L1b in the moisture storage unit 66a into the circulation path 62, and closing the first on-off valve 66c when causing the humidifying fluid L1a to flow in the circulation path 62.

At the first junction 62c of the circulation path 62, the humidifying fluid L1a flowing from the humidifying fluid storage section 61 and the moisture L1b flowing from the moisture supply section 66 merge. When the volume of the moisture L1b flowing from the moisture supply section 66 is greater than the volume of the humidifying fluid L1a flowing from the humidifying fluid storage section 61, the rate of change of the liquid level in the humidifying fluid storage section 61 becomes faster, resulting in greater variation in liquid level detection, making it difficult to detect the liquid level in a timely manner. Therefore, at the first junction 62c, it is desirable to set the pressure loss of the flow path on the moisture supply section 66 side to be the same as or greater than the pressure loss of the flow path on the humidifying fluid storage section 61 side.

Next, referring to the flowchart shown in FIG. 16, the flow of the concentration adjustment operation in the maintenance method for the capping device will be described in order, with the control performed by the control unit 90 in each step.

In step S201, the control unit 90 determines whether the first on-off valve 66c is open. If the first on-off valve 66c is open, the process proceeds to step S203. If the first on-off valve 66c is closed, the process proceeds to step S202, where the control unit 90 opens the first on-off valve 66c.

In step S203, the control unit 90 drives the first pump 63 for a third predetermined time T3 with the first opening/closing valve 66c open. As a result, as shown in FIG. 15, the humidifying fluid L1a flows in the circulation path 62 in the direction of the solid arrow shown in FIG. 15. Then, the moisture L1b flows in the moisture supply flow path 66b in the direction of the dashed arrow shown in FIG. 15 and merges with the humidifying fluid L1a at the first merging portion 62c. Then, the merged humidifying fluid L1a and moisture L1b become humidifying fluid L1a with an increased amount of moisture, and flows from the first merging portion 62c toward the unit cap 51a, flows in the circulation path 62 in the direction of the solid arrow shown in FIG. 15, and flows into the humidifying fluid storage portion 61. Then, the liquid level in the humidifying fluid storage portion 61 becomes higher than the first predetermined height H1.

In step S204, the control unit 90 acquires information on the liquid level in the humidifying fluid storage unit 61 from the detection unit 61a. Then, in step S205, the control unit 90 determines whether the liquid level is higher than the first predetermined height H1. If the liquid level is higher than the first predetermined height H1, the process proceeds to step S206. If the liquid level is lower than the first predetermined height H1, the process proceeds to step S207.

In step S206, the control unit 90 closes the first on-off valve 66c and proceeds to the circulation operation subroutine described above in step S100. When the control unit 90 ends the circulation operation subroutine, it ends the flow.

In step S207, the control unit 90 determines that the moisture L1b in the moisture storage unit 66a has disappeared, and in step S400, the control unit 90 executes a subroutine for the moisture storage unit pre-replacement operation, which will be described later. That is, when the amount of moisture L1b in the moisture storage unit 66a reaches an amount at which it is determined that the moisture storage unit 66a needs to be replaced, the capping device 50 performs the moisture storage unit pre-replacement operation. When the control unit 90 ends the subroutine for the moisture storage unit pre-replacement operation, it ends the flow.

In steps S203 to S205, the control unit 90 may drive the first pump 63 while obtaining information on the liquid level in the humidifying fluid storage unit 61 from the detection unit 61a with the first on-off valve 66c in an open state, and may stop the first pump 63 when the liquid level becomes higher than the first predetermined height H1. Then, when the third predetermined time T3 has elapsed since the first pump 63 was driven and the detection unit 61a detects that the liquid level is below the first predetermined height H1, the control unit 90 may determine in step S207 that the moisture L1b in the moisture storage unit 66a has disappeared.

<Cap replacement preparation operation>
The cap replacement preparation operation in the maintenance method for the capping device will now be described.
The cap replacement preparation operation is an operation performed by the capping device 50 when the cap is replaced. Before the cap is replaced, the humidifying fluid L1a in the cap is collected. In the capping device 50 of this embodiment, the cap unit 51 shown in Fig. 3 is replaced when the cap is replaced. The capping device 50 may be configured so that the unit cap 51a is replaced when the cap is replaced.

17, the capping device 50 performs a cap replacement preparation operation. During the cap replacement preparation operation, the first on-off valve 66c is closed and the second on-off valve 67b is open, and the control unit 90 controls the pressurized air supply unit 67 of the humidified fluid circulation mechanism 60 to supply the pressurized air through the pressurized air supply passage 66.
17. At this time, because the second on-off valve 67b is in an open state, the humidified fluid L1a in the circulation path 62 flows in the direction of the solid arrow shown in FIG.

As the pressurized air supply unit 67 continues to supply pressurized air into the circulation path 62, the humidified fluid L1a in the flow path from the second junction 66e to the inlet 61f of the circulation path that constitutes the circulation path 62 is pushed into the humidified fluid storage unit 61. Then, air is filled in the flow path from the second junction 66e to the inlet 61f. As a result, the humidified fluid L1a in the unit cap 51a is collected in the humidified fluid storage unit 61. In other words, the cap replacement preparation operation in the maintenance method for the cap device is an operation in which pressurized air is supplied from the pressurized air supply unit 67 into the unit cap 51a, which is an example of a cap, to discharge the humidified fluid L1a in the unit cap 51a to the humidified fluid storage unit 61 and supply the pressurized air into the unit cap 51a.

The moisture of the humidifying fluid L1a evaporates within the unit cap 51a, so the concentration of the humidifying fluid L1a within the unit cap 51a is high. As a result, when the humidifying fluid L1a within the unit cap 51a is collected into the humidifying fluid storage section 61, the concentration of the humidifying fluid L1a within the humidifying fluid storage section 61 becomes high. Also, when the humidifying fluid L1a within the unit cap 51a is collected into the humidifying fluid storage section 61, a small amount of the humidifying fluid L1a with a high concentration remains within the unit cap 51a. As a result, the next time the humidifying fluid L1a is replenished with moisture L1b, the concentration of the humidifying fluid L1a within the humidifying fluid storage section 61 becomes low. In order to minimize this change in concentration of the humidifying fluid L1a, it is desirable to make the volume of the humidifying fluid storage section 61 as large as possible within the size of the liquid ejection device 11.

Next, with reference to the flowchart shown in FIG. 18, the flow of the cap replacement preparation operation in the maintenance method for the cap device will be described in order, with the control executed by the control unit 90 in each step.

In step S301, the control unit 90 determines whether the first on-off valve 66c is in a closed state. If the first on-off valve 66c is in a closed state, the process proceeds to step S303. If the first on-off valve 66c is in an open state, the process proceeds to step S302. Then, in step S302, the control unit 90 closes the first on-off valve 66c.

In step S303, the control unit 90 opens the second on-off valve 67b. Then, in step S304, the control unit 90 drives the second pump 67c for a fourth predetermined time T4 with the first on-off valve 66c in a closed state and the second on-off valve 67b in an open state. This causes the humidifying fluid L1a in the unit cap 51a to be collected in the humidifying fluid storage unit 61. Then, in step S305, the control unit 90 closes the second on-off valve 67b, ending the flow.

<Operation before replacing the water storage unit>
An operation before replacing the water storage unit in the maintenance method of the capping device will be described.
As shown in FIG. 19, the cap device 50 performs a pre-exchange operation of the moisture storage unit. The pre-exchange operation of the moisture storage unit is an operation executed by the control unit 90 when the amount of moisture L1b in the moisture storage unit 66a reaches an amount at which it is determined that the moisture storage unit 66a needs to be replaced. In this embodiment, in the above-mentioned concentration adjustment operation, when the first pump 63 is driven for the third predetermined time T3, if the liquid level in the humidifying fluid storage unit 61 is detected by the detection unit 61a to be below the first predetermined height H1, the control unit 90 determines that the moisture in the moisture storage unit 66a has run out. That is, when the concentration of the humidifying fluid L1a in the circulation path 62 cannot be restored to the concentration before the moisture evaporated in the unit cap 51a, the control unit 90 determines that the moisture storage unit 66a needs to be replaced.

When it is determined that the moisture storage section 66a needs to be replaced, the control section 90 executes the same operation as the cap replacement preparation operation described above. Then, after the humidifying fluid L1a in the unit cap 51a is collected, the first flushing parameter table is switched to the second flushing parameter table when the moisture L1b in the moisture storage section 66a is depleted until the moisture storage section 66a is replaced.

The parameter table is a table that describes the conditions and number of times for flushing, and flushing is performed based on this table. When the humidifying fluid L1a in the unit cap 51a is collected, the space SP in the unit cap 51a is not humidified by the humidifying fluid L1a, so the control unit 90 performs a blank ejection, which is the ejection of liquid unrelated to printing, into the space SP in the unit cap 51a to humidify the nozzle 22. Therefore, the conditions and number of times for flushing are changed to parameters suitable for humidifying the nozzle 22.

In summary, the pre-water storage unit replacement operation includes the above-mentioned cap replacement preparation operation and the capping device 50 humidifying the nozzles 22 by performing a blank ejection, which is the ejection of liquid unrelated to printing, from the liquid ejection head 21 into the space SP within the unit cap 51a, which is an example of a cap, until the water storage unit 66a is replaced.

The aforementioned circulation operation, which had been performed periodically until then, is not executed until the moisture storage section 66a is replaced. When the moisture storage section 66a is replaced, the control section 90 returns the second parameter table to the first parameter table that existed before the parameter table was switched, and then starts the aforementioned concentration adjustment operation. After that, the aforementioned circulation operation is also executed periodically.

Next, with reference to the flowchart shown in FIG. 20, the flow of operations before replacing the moisture storage unit in the maintenance method for the capping device will be described in order, with the control performed by the control unit 90 in each step.

In step S300, the control unit 90 executes the subroutine for the cap replacement preparation operation described above. When the subroutine for the cap replacement preparation operation ends, in step S401, the control unit 90 switches the parameter table and ends the flow.

<About the humidification fluid filling operation>
The humidification fluid filling operation in the maintenance method for the capping device will now be described.
The humidification fluid filling operation is a flow performed to accommodate the humidification fluid L1a in the humidification fluid storage section 61 before the liquid ejection device 11 shown in FIG. 1 is assembled and shipped from the factory. After the humidification fluid L1a is accommodated in the humidification fluid storage section 61, the liquid ejection device 11 is shipped from the factory in a state in which the humidification fluid L1a in the unit cap 51a is collected in the humidification fluid storage section 61. The humidification fluid filling operation is performed before the moisture storage section 66a is attached to the moisture supply flow path 66b. When the moisture storage section 66a has already been attached to the moisture supply flow path 66b, the moisture storage section 66a is removed from the moisture supply flow path 66b, and then the flow of the humidification fluid filling operation is executed. In the flow of the humidification fluid filling operation, some steps are performed manually by an operator.

21, a humidification fluid pack 68 containing humidification fluid L1a to be contained in the humidification fluid container 61 is attached to the moisture supply flow path 66b. The humidification fluid pack 68 communicates with the moisture supply flow path 66b at an outlet 68a of the humidification fluid pack 68. As a result, when the first opening/closing valve 66c is in an open state, the humidification fluid pack 68 communicates with the first junction 66c.
2c are in communication with each other via the moisture supply passage 66b.

The circulation path 62 has a clamp portion 62d upstream of the first junction 62c. It is desirable that the distance between the clamp portion 62d and the first junction 62c be as short as possible. When the clamp portion 62d is closed by the clamp 69, the flow path is closed at the clamp portion 62d. In other words, the humidification fluid storage portion 61 and the first junction 62c are not in communication with each other due to the clamp 69. Note that a clamp is a device that is provided midway through a flow path and adjusts the flow rate of the flow path by clamping the flow path.

In this state, the first opening/closing valve 66c is open, and the control unit 90 drives the first pump 63 to cause the humidifying fluid L1a to flow in the circulation path 62 in the direction of the solid arrow shown in FIG. 21 in the humidifying fluid circulation mechanism 60. At this time, the humidifying fluid L1a in the humidifying fluid pack 68 flows in the direction of the solid arrow shown in FIG. 21. Then, since the first opening/closing valve 66c is open, the humidifying fluid L1a is supplied into the circulation path 62. Also, at this time, the clamp portion 62d is closed by the clamp 69. Therefore, the humidifying fluid L1a in the humidifying fluid storage portion 61 is not supplied into the circulation path 62. As a result, a predetermined amount of the humidifying fluid L1a in the humidifying fluid pack 68 flows into the humidifying fluid storage portion 61. Then, the liquid level in the humidifying fluid storage portion 61 becomes higher than the first predetermined height H1.

The control unit 90 closes the first opening/closing valve 66c, and the operator removes the clamp 69. The humidifying fluid L1a then circulates through the circulation path 62, stabilizing the liquid level in the humidifying fluid storage unit 61. The control unit 90 then executes a cap replacement preparation operation, causing the humidifying fluid L1a in the unit cap 51a to be collected into the humidifying fluid storage unit 61. The liquid ejection device 11 is shipped from the factory in this state.

Next, with reference to the flow chart shown in FIG. 22, the process in each step of the flow of the humidification fluid filling operation will be described in order.
In step S501, an operator attaches the humidification fluid pack 68. Then, in step S502, an operator attaches the clamp 69 to the clamp portion 62d and closes the clamp 69.

In step S503, the control unit 90 determines whether the first on-off valve 66c is open. If the first on-off valve 66c is open, the process proceeds to step S505. If the first on-off valve 66c is closed, the process proceeds to step S504. Then, in step S504, the control unit 90 opens the first on-off valve 66c.

In step S505, the control unit 90 starts driving the first pump 63. As a result, as shown in FIG. 21, the humidification fluid L1a flows in the moisture supply flow path 66b in the direction of the solid arrow shown in FIG. 21. The humidification fluid L1a then flows from the first junction 62c toward the unit cap 51a, and in the circulation path 62 in the direction of the solid arrow shown in FIG. 21.

In step S506, the control unit 90 acquires information on the liquid level in the humidifying fluid storage unit 61 from the detection unit 61a. Then, in step S507, it is determined whether the liquid level in the humidifying fluid storage unit 61 is higher than the first predetermined height H1. If the liquid level is higher than the first predetermined height H1, the process proceeds to step S508. Then, in step S508, the control unit 90 stops driving the first pump 63. If the liquid level is lower than the first predetermined height H1, the control unit 90 continues driving the first pump 63 and proceeds to step S506.

In step S509, the control unit 90 closes the first opening/closing valve 66c. Then, in step S510, the clamp 69 is removed by the operator.
In step S511, the control unit 90 drives the first pump 63 for a first predetermined time T1 with the first on-off valve 66c in a closed state, thereby causing the humidifying fluid L1a to flow in the circulation path 62 in the direction of the solid arrow shown in FIG.

In step S512, the control unit 90 stops the first pump 63 for the second predetermined time T2 with the first on-off valve 66c in a closed state. This stabilizes the liquid level state in the humidification fluid storage unit 61.

In step S513, the control unit 90 obtains information on the liquid level in the humidifying fluid storage unit 61 from the detection unit 61a. Then, in step S514, it is determined whether the liquid level in the humidifying fluid storage unit 61 is higher than the first predetermined height H1. If the liquid level is higher than the first predetermined height H1, the process proceeds to step S300. Then, in step S300, the control unit 90 executes a subroutine for the cap replacement preparation operation. This causes the humidifying fluid L1a in the unit cap 51a to be collected in the humidifying fluid storage unit 61. Note that when the cap replacement preparation operation is executed, the liquid level may be further increased by the humidifying fluid L1a in the unit cap 51a. Therefore, in the cap replacement preparation operation, the first predetermined height H1 is set to a height that prevents the humidifying fluid storage unit 61 from being completely filled with the humidifying fluid L1a before the humidifying fluid L1a in the unit cap 51a is completely collected in the humidifying fluid storage unit 61.

If the liquid level is lower than the first predetermined level H1 in step S514, the control unit 90 proceeds to step S502. This causes the humidifying fluid L1a in the humidifying fluid pack 68 to be supplied again to the circulation path 62. In other words, fine adjustment of the liquid level in the humidifying fluid storage unit 61 is performed.

When the cap replacement preparation subroutine is completed, in step S515, the operator removes the humidification fluid pack 68 and attaches the moisture storage section 66a. The flow then ends.

<Liquid Ejected by Liquid Ejection Head>
Ink, which is an example of the liquid ejected by the liquid ejection device 11, will be described in detail below.
The ink used in the liquid ejection device 11 contains a resin in its composition, and does not substantially contain glycerin, which has a boiling point of 290° C. under 1 atmosphere. If the ink substantially contains glycerin, the drying property of the ink is significantly reduced. As a result, not only does the unevenness of the image's shading become noticeable on various media, particularly on non-ink-absorbent or low-ink-absorbent media, but the ink does not adhere well. Furthermore, it is preferable that the ink does not substantially contain alkyl polyols (other than the above-mentioned glycerin) with a boiling point of 280° C. or higher under 1 atmosphere.

In this specification, "substantially free" means that the amount of glycerin is not more than the amount that fully exerts the significance of adding it. Quantitatively speaking, it is preferable that the ink does not contain more than 1.0% by mass of glycerin relative to the total mass of the ink (100% by mass), more preferably less than 0.5% by mass, even more preferably less than 0.1% by mass, even more preferably less than 0.05% by mass, and particularly preferably less than 0.01% by mass. And it is most preferable that the ink does not contain more than 0.001% by mass of glycerin.

Next, additives (components) that are or can be contained in the ink will be described.
[1. Coloring material]
The ink may include a colorant selected from pigments and dyes.

[1-1. Pigments]
By using a pigment as a coloring material, the light resistance of the ink can be improved. The pigment may be either an inorganic pigment or an organic pigment. The inorganic pigment is not particularly limited, but examples thereof include carbon black, iron oxide, titanium oxide, and silica oxide.

The organic pigments are not particularly limited, but examples thereof include quinacridone pigments, quinacridonequinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. Specific examples of organic pigments include the following:

Pigments used in cyan ink include C.I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 15:34, 16, 18, 22, 60, 65, 66, C.I. Bat Blue 4, 60. Of these, C.I. Pigment Blue 15:3 and 15:4 are preferred.

Pigments used in magenta ink include C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57:1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. Pigment Violet 19, 23, 32, 33, 36, 38, 43, and 50. Among them, one or more selected from the group consisting of C.I. Pigment Red 122, C.I. Pigment Red 202, and C.I. Pigment Violet 19 are preferred.

Pigments used in yellow ink include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, and 213. Among them, one or more selected from the group consisting of C.I. Pigment Yellow 74, 155, and 213 are preferred.

Pigments used in inks of colors other than those mentioned above, such as green ink and orange ink, include conventionally known pigments.
The average particle diameter of the pigment is preferably 250 nm or less, since this can suppress clogging in the nozzle 22 and improve the ejection stability. The average particle diameter in this specification is based on volume. As a measurement method, for example, it can be measured by a particle size distribution measuring device that uses the laser diffraction scattering method as its measurement principle. As an example of the particle size distribution measuring device, a particle size distribution meter (e.g., Microtrack UPA manufactured by Nikkiso Co., Ltd.) that uses the dynamic light scattering method as its measurement principle can be mentioned.

[1-2. Dyes]
A dye can be used as the coloring material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. The content of the coloring material is preferably 0.4 to 12% by mass, and more preferably 2% by mass or more and 5% by mass or less, based on the total mass (100% by mass) of the ink.

[2. Resin]
The ink contains a resin. When the ink contains a resin, a resin film is formed on the medium, and as a result, the ink is sufficiently fixed on the medium, and the effect of mainly improving the abrasion resistance of the image is exhibited. For this reason, the resin emulsion is preferably a thermoplastic resin. The heat deformation temperature of the resin is preferably 40° C. or higher, and more preferably 60° C. or higher, since this has the advantageous effect of making the nozzle 22 less likely to clog and providing the medium with abrasion resistance.

Here, "heat distortion temperature" in this specification refers to a temperature value expressed as glass transition temperature (Tg) or minimum film forming temperature (MFT). In other words, "heat distortion temperature is 40°C or higher" means that either Tg or MFT is 40°C or higher. Since MFT is easier to grasp than Tg as to the superiority or inferiority of the redispersibility of the resin, it is preferable that the heat distortion temperature is a temperature value expressed as MFT. If the ink has excellent redispersibility of the resin, the ink does not solidify and the nozzle 22 is less likely to become clogged.

Specific examples of the thermoplastic resin include, but are not limited to, poly(meth)acrylic acid esters or copolymers thereof, polyacrylonitrile or copolymers thereof, (meth)acrylic polymers such as polycyanoacrylate, polyacrylamide, and poly(meth)acrylic acid, polyethylene, polypropylene, polybutene, polyisobutylene, and polystyrene, as well as copolymers thereof, as well as polyolefin polymers such as petroleum resins, coumarone-indene resins, and terpene resins, vinyl acetate or vinyl alcohol polymers such as polyvinyl acetate or copolymers thereof, polyvinyl alcohol, polyvinyl acetal, and polyvinyl ether, halogen-containing polymers such as polyvinyl chloride or copolymers thereof, polyvinylidene chloride, fluororesins, and fluororubbers, nitrogen-containing vinyl polymers such as polyvinylcarbazole, polyvinylpyrrolidone or copolymers thereof, polyvinylpyridine, and polyvinylimidazole, diene polymers such as polybutadiene or copolymers thereof, polychloroprene, and polyisoprene (butyl rubber), as well as other ring-opening polymerization resins, condensation polymerization resins, and natural polymer resins.

The resin content is preferably 1 to 30% by mass, and more preferably 1 to 5% by mass, relative to the total mass of the ink (100% by mass). When the content is within the above range, the gloss and abrasion resistance of the topcoat image formed can be made even better. Examples of resins that may be contained in the ink include resin dispersants, resin emulsions, and waxes.

[2-1. Resin emulsion]
The ink may contain a resin emulsion. When the medium is heated, the resin emulsion preferably forms a resin coating together with the wax (emulsion), thereby exerting the effect of sufficiently fixing the ink on the medium and improving the abrasion resistance of the image. Due to the above effect, when a medium is printed with the ink containing the resin emulsion, the ink has excellent abrasion resistance, particularly on a medium that is non-absorbent or has low ink absorption.

The resin emulsion that functions as a binder is contained in the ink in an emulsion state. By containing the resin that functions as a binder in the ink in an emulsion state, it is easy to adjust the viscosity of the ink to an appropriate range for the inkjet recording method, and the storage stability and ejection stability of the ink can be improved.

Examples of resin emulsions include, but are not limited to, homopolymers or copolymers of (meth)acrylic acid, (meth)acrylic acid esters, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride, fluororesins, and natural resins. Among these, either methacrylic resin or styrene-methacrylic acid copolymer resin is preferred, either acrylic resin or styrene-acrylic acid copolymer resin is more preferred, and styrene-acrylic acid copolymer resin is even more preferred. The above copolymers may be in the form of any of random copolymers, block copolymers, alternating copolymers, and graft copolymers.

The average particle size of the resin emulsion is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink. The content of the resin emulsion among the resins is preferably in the range of 0.5 to 7 mass% relative to the total mass of the ink (100 mass%). If the content is within the above range, the solids concentration can be reduced, thereby further improving the ejection stability.

[2-2. Wax]
The ink may contain a wax. When the ink contains a wax, the ink has better fixability on non-ink absorbing and low ink absorbing media. Among them, the wax is preferably an emulsion type. The wax is not limited to the following, but may be, for example, polyethylene wax, paraffin wax, and polyolefin wax, and among them, polyethylene wax described later is preferable. In this specification, "wax" mainly means solid wax particles dispersed in water using a surfactant described later.

By including polyethylene wax in the ink, the ink can have excellent abrasion resistance. The average particle size of the polyethylene wax is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.

The content of the polyethylene wax (solid content equivalent) is preferably, independently of each other, in the range of 0.1 to 3 mass% relative to the total mass of the ink (100 mass%), more preferably in the range of 0.3 to 3 mass%, and even more preferably in the range of 0.3 to 1.5 mass%. If the content is within the above range, the ink can be well solidified and fixed even on a non-ink-absorbing or low-ink-absorbing medium, and the storage stability and ejection stability of the ink can be further improved.

3. Surfactants
The ink may contain a surfactant. Examples of the surfactant include, but are not limited to, nonionic surfactants. Nonionic surfactants have the effect of spreading the ink evenly on a medium. For this reason, when printing is performed using ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be obtained. Examples of such nonionic surfactants include, but are not limited to, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivative, and fluorine-based surfactants, among which silicon-based surfactants are preferred.

The content of the surfactant is preferably in the range of 0.1% by mass or more and 3% by mass or less relative to the total mass of the ink (100% by mass), in order to further improve the storage stability and ejection stability of the ink.

[4. Organic Solvent]
The ink may contain a known volatile water-soluble organic solvent. However, as described above, it is preferable that the ink does not substantially contain glycerin (having a boiling point of 290° C. under 1 atmospheric pressure), which is a type of organic solvent, and does not substantially contain alkyl polyols (other than the above-mentioned glycerin) having a boiling point of 280° C. or higher under an equivalent pressure of 1 atmospheric pressure.

[5. Aprotic polar solvents]
The ink may contain an aprotic polar solvent. By containing an aprotic polar solvent in the ink, the resin particles contained in the ink are dissolved, so that clogging of the nozzle 22 during printing can be effectively suppressed. In addition, since the ink has a property of dissolving a medium such as vinyl chloride, the adhesion of the image is improved.

The aprotic polar solvent is not particularly limited, but preferably contains one or more selected from pyrrolidones, lactones, sulfoxides, imidazolidinones, sulfolanes, urea derivatives, dialkylamides, cyclic ethers, and amide ethers. Representative examples of pyrrolidones include 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. Representative examples of lactones include γ-butyrolactone, γ-valerolactone, and ε-caprolactone. Representative examples of sulfoxides include dimethyl sulfoxide and tetramethylene sulfoxide.

A typical example of imidazolidinones is 1,3-dimethyl-2-imidazolidinone, typical examples of sulfolanes are sulfolane and dimethylsulfolane, and typical examples of urea derivatives are dimethylurea and 1,1,3,3-tetramethylurea. Typical examples of dialkylamides are dimethylformamide and dimethylacetamide, and typical examples of cyclic ethers are 1,4-dioxane and tetrahydrofuran.

Among these, pyrrolidones, lactones, sulfoxides, and amide ethers are particularly preferred from the viewpoint of the above-mentioned effects, and 2-pyrrolidone is the most preferred. The content of the above aprotic polar solvent is preferably in the range of 3 to 30% by mass, and more preferably in the range of 8 to 20% by mass, relative to the total mass of the ink (100% by mass).

[6. Other Ingredients]
In addition to the above components, the ink may further contain a mildew inhibitor, a rust inhibitor, a chelating agent, and the like.

<About humidifying fluid>
The components of the surfactant mixed into the humidifying fluid L1a will be described.
Examples of surfactants that can be used include cationic surfactants such as alkylamine salts and quaternary ammonium salts; anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates, and fatty acid salts; amphoteric surfactants such as alkyldimethylamine oxides and alkylcarboxybetaines; and nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers. Of these, anionic surfactants or nonionic surfactants are particularly preferred.

The content of the surfactant is preferably 0.1 to 5.0% by mass with respect to the total mass of the humidifying fluid L1a. Furthermore, from the viewpoint of foaming property and defoaming property after foaming, the content of the surfactant is preferably 0.5 to 1.5% by mass with respect to the total mass of the humidifying fluid L1a. The surfactant may be only one type or may be two or more types. Furthermore, the surfactant contained in the humidifying fluid L1a is preferably the same as the surfactant contained in the ink (liquid). For example, when the surfactant contained in the ink (liquid) is a nonionic surfactant, examples of the nonionic surfactant include, but are not limited to, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivative, and fluorine-based surfactants, and among them, silicon-based surfactants are preferred.

In particular, in order to ensure that the foam height immediately after foaming and 5 minutes after foaming using the Ross-Miles method is within the above-mentioned range (foam height immediately after foaming is 50 mm or more, and foam height 5 minutes after foaming is 5 mm or less), it is preferable to use an adduct in which ethylene oxide (EO) is added to acetylenic diol with an added mole number of 4 to 30 as the surfactant, and the content of the adduct is 0.1 to 3.0% by weight based on the total weight of the cleaning solution. Furthermore, in order to ensure that the foam height immediately after foaming and 5 minutes after foaming using the Ross-Miles method is within the above-mentioned preferred range (foam height immediately after foaming is 100 mm or more, and foam height 5 minutes after foaming is 5 mm or less), it is preferable to use an adduct in which ethylene oxide (EO) is added to acetylenic diol with an added mole number of 10 to 20, and the content of the adduct is 0.5 to 1.5% by weight based on the total weight of the cleaning solution. However, if the content of the ethylene oxide adduct of acetylenic diol is too high, the critical micelle concentration may be reached, resulting in an emulsion.

Surfactants have the function of making it easier for the aqueous ink to wet and spread on the recording medium. There are no particular limitations on the surfactants that can be used in the present invention, and examples of surfactants that can be used include anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers; cationic surfactants such as alkylamine salts and quaternary ammonium salts; silicone surfactants; and fluorine-based surfactants.

The surfactant has the effect of breaking down and dispersing the aggregates due to the interfacial activity between the humidifying fluid L1a and the aggregates. It also works to lower the surface tension of the cleaning liquid, making it easier for the cleaning liquid to penetrate between the aggregates and the nozzle surface 23, and making it easier to peel the aggregates off the nozzle surface 23.

Any surfactant can be suitably used as long as it is a compound that has a hydrophilic portion and a hydrophobic portion in the same molecule. Specific examples are preferably those represented by the following formulas (I) to (IV). That is, examples include polyoxyethylene alkyl phenyl ether surfactants of the following formula (I), acetylene glycol surfactants of the following formula (II), polyoxyethylene alkyl ether surfactants of the following formula (III), and polyoxyethylene polyoxypropylene alkyl ether surfactants of the following formula (IV).

(R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k is 5 to 20)

(m, n≦20, 0<m+n≦40)

(R is a hydrocarbon chain having 6 to 14 carbon atoms which may be branched, and n is 5 to 20).

(R is a hydrocarbon chain having 6 to 14 carbon atoms, and m and n are numbers up to 20.)
Other than the compounds of the formulas (I) to (IV), for example, alkyl and aryl ethers of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine-based surfactants, and lower alcohols such as ethanol and 2-propanol can be used, with diethylene glycol monobutyl ether being particularly preferred.

The operation of this embodiment will be described.
After the liquid ejection device 11 is assembled, and before it is shipped from the factory, the flow of the humidification fluid filling operation shown in FIG. 22 is carried out.

21 , in the humidifying fluid filling operation, with the humidifying fluid L1a in the humidifying fluid storage portion 61 not being supplied into the circulation path 62 by the clamp 69 and with the first on-off valve 66c in an open state, the control portion 90 drives the first pump 63 to cause the humidifying fluid L1a to flow in the circulation path 62 in the direction of the solid arrow shown in Fig. 21 . By driving the first pump 63 until the detection portion 61a detects that the liquid level in the humidifying fluid storage portion 61 is above the first predetermined height H1, a predetermined amount of the humidifying fluid L1a in the humidifying fluid pack 68 can be stored in the humidifying fluid storage portion 61. Therefore, the liquid ejection device 11 can be shipped from the factory with a predetermined amount of the humidifying fluid L1a stored in the humidifying fluid storage portion 61.

By the cap replacement preparation operation executed by the control unit 90 at the end of the humidification fluid filling operation, most of the humidification fluid L1a in the unit cap 51a is discharged outside the unit cap 51a. Therefore, the liquid ejection device 11 can be shipped from the factory with almost no humidification fluid L1a remaining in the unit cap 51a.

The liquid ejection device 11 shipped from the factory is installed by the user, and the use of the liquid ejection device 11 is started. After the liquid ejection device 11 is installed, and before recording is performed on the medium M for the first time, the control unit 90 executes the circulation operation flow shown in FIG. 14.

As shown in FIG. 13, during circulation operation, with the first on-off valve 66c in a closed state, the control unit 90 drives the first pump 63 to cause the humidifying fluid L1a to flow in the circulation path 62 in the direction of the solid arrow in FIG. 13. This allows the humidifying fluid L1a to flow through the unit cap 51a, which was shipped with almost no humidifying fluid L1a. The humidifying chamber 55 of the unit cap 51a can then be filled with humidifying fluid L1a.

More specifically, as shown in FIG. 7, the humidification fluid L1a can be circulated within the humidification chamber 55, which is formed as a single flow path connecting the inlet 55a and the outlet 55b by the groove 55c and the first moisture permeable membrane 54 covering the groove 55c. In other words, the groove 55c of the humidification chamber 55, which was almost devoid of humidification fluid L1a at the time of shipment, can be filled with humidification fluid L1a.

The humidification chamber 55 is formed in such a single-path flow path, which makes it easier to fill the humidification chamber 55 with the humidification fluid L1a by the circulation operation. Furthermore, the humidification chamber 55 is formed in a winding flow path, which makes it possible to prevent the humidification fluid L1a filled in the humidification chamber 55 by the circulation operation from flowing out of the humidification chamber 55 from the inlet 55a or the outlet 55b.

As shown in FIG. 3, the cap device 50 is configured with a plurality of unit caps 51a lined up. As described above, the outlet 55b of one of the plurality of unit caps 51a is connected to the inlet 55a of another unit cap 51a adjacent to that unit cap 51a. As shown in FIG. 11, the inlet 55a located most upstream is connected to the supply flow path 62a, and the outlet 55b located most downstream is connected to the recovery flow path 62b. This allows the humidifying fluid L1a to be filled into the plurality of unit caps 51a using only one supply flow path 62a and recovery flow path 62b.

As shown in FIG. 8, the humidification chamber 55 is provided at an angle to the horizontal. The inlet 55a and the outlet 55b are provided above the vertical center of the humidification chamber 55. This prevents the humidification fluid L1a filled in the humidification chamber 55 by the circulation operation from flowing out of the humidification chamber 55 from the inlet 55a or the outlet 55b due to head pressure.

As shown in FIG. 2, when the liquid ejection head 21 in the liquid ejection device 11 records on the medium M, the medium M in the medium storage section 16 shown in FIG. 1 is fed, and the medium M travels through the transport path 19 toward the recording section 20. Then, in the recording section 20, the liquid ejection head 21 ejects liquid toward the medium M transported in the first transport direction Z1. Then, the liquid ejection device 11 alternates between a transport operation that transports the medium M to the next recording position and a recording operation that ejects liquid from the liquid ejection head 21, thereby recording characters, images, etc. on the medium M.

As shown in FIG. 8, when the liquid ejection head 21 is not ejecting liquid, the liquid ejection device 11 performs a capping operation in which the cap unit 51 contacts the nozzle surface 23 of the liquid ejection head 21 so as to surround the nozzle 22. In other words, when the liquid ejection head 21 is not ejecting liquid, the unit cap 51a is kept in contact with the nozzle surface 23 of the liquid ejection head 21 so as to surround the nozzle 22.

As shown in FIG. 2, during capping, the cap unit 51 moves from the retracted position in the third direction D3 to the maintenance position, and then the head unit 24 moves from the recording position in the first direction D1 to the maintenance position. This causes the cap unit 51 to cap the head unit 24. That is, the cap device 50 and the liquid ejection head 21 come into contact. This allows the contact surface 56f of the unit cap 51a to come into contact with the nozzle surface 23 of the liquid ejection head 21, allowing the seal portion 56e to seal the nozzle surface 23.

As shown in FIG. 10, the humidification chamber 55 is filled with humidification fluid L1a. The moisture evaporated from the humidification fluid L1a can pass through the first moisture permeable membrane 54 and absorber 53 together with the moist air containing the moisture, and reach the recess 57. The moisture can then humidify the recess 57. This allows the space SP surrounding the opening of the nozzle 22 when the unit cap 51a comes into contact with the liquid ejection head 21 to be humidified, thereby allowing the opening of the nozzle 22 to be humidified. Furthermore, the viscosity of the liquid in the nozzle 22 is suppressed, preventing ejection defects from occurring.

As shown in FIG. 8, in the humidification chamber 55, the flow path is routed around the entire bottom surface of the unit cap 51a, so that the entire inside of the recess 57 can be humidified. This allows the openings of the multiple nozzles 22 in the liquid ejection head 21 to be more uniformly humidified.

As shown in FIG. 8, the liquid ejection device 11 periodically performs flushing, which is an ejection operation for ejecting droplets unrelated to printing from the nozzles 22 into the space SP within the unit cap 51a. Even during flushing, the unit cap 51a is kept in contact with the nozzle surface 23 of the liquid ejection head 21 so as to surround the nozzles 22.

As shown in FIG. 2, during flushing or cleaning, the cap unit 51 moves from the retracted position in the third direction D3 to the maintenance position, and then the head unit 24 moves from the recording position in the first direction D1 to the maintenance position. This brings the cap device 50 into contact with the liquid ejection head 21. This allows the contact surface 56f of the unit cap 51a to come into contact with the nozzle surface 23 of the liquid ejection head 21, allowing the seal portion 56e to seal the nozzle surface 23.

As shown in FIG. 9, the waste liquid L2 discharged from the nozzle 22 to the recess 57 by flushing or cleaning passes through the regulating member 52 and the absorbent 53. The waste liquid L2 is absorbed by the absorbent 53. The waste liquid L2 absorbed by the absorbent 53 spreads throughout the absorbent 53. When the absorbent 53 approaches a state where it cannot absorb any more waste liquid L2, the waste liquid L2 flows vertically in the absorbent 53 due to gravity. Since the first moisture permeable membrane 54 does not have liquid permeability, the waste liquid L2 does not flow into the humidification chamber 55. Since the recess 57 has a discharge hole 56b, the waste liquid L2 that the absorbent 53 cannot absorb in the recess 57 can be discharged from the discharge hole 56b to the outside of the unit cap 51a.

The drain hole 56b may be provided in the recess 57 at a position lower than the first moisture permeable membrane 54. The waste liquid L2 can be discharged to the outside of the unit cap 51a through the drain hole 56b by gravity. This can prevent the surface of the first moisture permeable membrane 54 from being blocked by the waste liquid L2, preventing gas from passing through.

The drain hole 56b may be provided at the bottom of the recess 57. The waste liquid L2 can be discharged from the drain hole 56b to the outside of the unit cap 51a by gravity. This can prevent the waste liquid L2 from remaining in the recess 57.

As shown in FIG. 11, the recess 57 has an atmosphere communication hole 56a for connecting the space SP to the atmosphere. As described above, in this embodiment, the third opening/closing valve 58b, which connects the space SP to the atmosphere, is opened and closed by the movement of the cap unit 51. This makes it possible to connect the space SP to the atmosphere by opening and closing the third opening/closing valve 58b without using an actuator dedicated to the third opening/closing valve.

When the third on-off valve 58b is opened or closed, the space SP is connected to the atmosphere. As a result, even when the space SP is formed surrounding the opening of the nozzle 22, the atmosphere flows into the space SP, making it easier to discharge the waste liquid L2 in the recess 57 to the outside of the unit cap 51a through the discharge hole 56b.

During flushing or cleaning, the first atmosphere communication passage 58a is open and the liquid ejection head 21 discharges liquid into the unit cap 51a. The first atmosphere communication passage 58a is also open during capping when the liquid ejection head 21 is not ejecting liquid. In other words, because the first atmosphere communication passage 58a is open most of the time, it is possible to prevent waste liquid L2 from remaining in the recess 57.

As shown in FIG. 10, the air vent 56a may be provided above the vertical center of the recess 57. This can prevent the air vent 56a from being blocked by the waste liquid L2, preventing the waste liquid L2 from being discharged from the recess 57.

The air communication hole 56a may be provided at a position in the recess 57 higher than the first moisture permeable membrane 54. This can prevent the air communication hole 56a from being blocked by the waste liquid L2 flowing over the surface of the first moisture permeable membrane 54, preventing the waste liquid L2 from being discharged from within the recess 57.

As shown in FIG. 9, the waste liquid L2 discharged from the nozzle 22 into the recess 57 by flushing or cleaning is absorbed by the absorbent 53. Also, as shown in FIG. 10, the moisture that evaporates from the humidifying fluid L1a and passes through the first moisture permeable membrane 54 humidifies the waste liquid L2 absorbed by the absorbent 53. As a result, when the viscosity of the waste liquid L2 absorbed by the absorbent 53 is high, the viscosity of the waste liquid L2 is adjusted by the moisture evaporated from the humidifying fluid L1a. The space SP can be humidified more efficiently by the moisture evaporated from the humidifying fluid L1a and the waste liquid L2 with the adjusted viscosity.

In this embodiment, the moisturizing power of the humidifying fluid L1a is equivalent to that of fresh ink, so when the ink absorbed in the absorber 53 is thickened, the ink absorbed in the absorber 53 can be moisturized to maintain the moisturizing power of the ink absorbed in the absorber 53 at a level equivalent to that of fresh ink.

The waste liquid L2 absorbed by the absorber 53 spreads throughout the absorber 53. This allows the distribution of the waste liquid L2 absorbed by the absorber 53 to be closer to uniform, so the entire space SP can be more uniformly humidified. This also allows the openings of the multiple nozzles 22 of the liquid ejection head 21 to be more uniformly humidified.

When flushing or cleaning is performed, the liquid discharged from the nozzles 22 of the liquid ejection head 21 adheres to the nozzle surface 23. Therefore, after flushing or cleaning, the liquid ejection device 11 performs wiping.

As shown in FIG. 4, after the head unit 24 moves from the recording position in the first direction D1 to the maintenance position, the wiper carriage 41 moves from the retracted position in the fifth direction D5 to the turn back position. This allows the nozzle surface 23 of the head unit 24 to be wiped by the wiper member 42 of the wiper carriage 41. The liquid adhering to the nozzle surface 23 can then be collected in the wiper carriage 41 as waste liquid L2. This allows the liquid adhering to the nozzle surface 23 of the liquid ejection head 21 and dirt such as dust to be removed.

As shown in FIG. 11, the waste liquid recovery mechanism 80 uses the third pump 82 to cause the waste liquid L2 recovered by flushing or cleaning and the waste liquid L2 recovered by wiping to flow out through the waste liquid recovery path 81 into the waste liquid storage section 86. This allows both the waste liquid L2 recovered by flushing or cleaning and the waste liquid L2 recovered by wiping to be stored together in the waste liquid storage section 86.

The fourth pump 84 is a pressure reducing pump. Therefore, in the first waste liquid recovery path 81a, the fourth pump 84 lowers the air pressure in the buffer chamber 83 by discharging the air in the buffer chamber 83 to the outside of the buffer chamber 83. This makes it easier for the waste liquid L2 recovered by flushing or cleaning to flow into the buffer chamber 83. In addition, it makes it easier for the waste liquid L2 recovered by flushing or cleaning to flow into the waste liquid storage section 86. In other words, it is possible to prevent the waste liquid L2 from remaining in the recess 57.

As shown in FIG. 10, during capping, the moisture contained in the humidifying fluid L1a filled in the humidifying chamber 55 humidifies the space SP surrounding the opening of the nozzle 22 when the unit cap 51a comes into contact with the liquid ejection head 21. This reduces the amount of moisture contained in the humidifying fluid L1a filled in the humidifying chamber 55. In other words, the concentration of the humidifying fluid L1a filled in the humidifying chamber 55 becomes greater than the concentration of the humidifying fluid L1a contained in the humidifying fluid storage section 61.

As shown in FIG. 13, in a capping device 50 equipped with a humidifying fluid storage section 61, a supply flow path 62a, a recovery flow path 62b, and a first pump 63, the humidifying fluid L1a is circulated in the circulation path 62 by a circulation operation. This allows the humidifying fluid L1a in the circulation path 62 to be stirred. By stirring the humidifying fluid L1a in the circulation path 62, the concentration of the humidifying fluid L1a throughout the circulation path 62 can be made uniform. In other words, the circulation operation allows the amount of moisture contained in the humidifying fluid L1a filled in the humidifying chamber 55 to be returned to an amount close to the amount at the time of shipment.

The control unit 90 periodically performs the circulation operation by managing the time using a timer or the like. This makes it possible to make the concentration of the humidifying fluid L1a throughout the circulation path 62 uniform at an appropriate timing. In other words, it is possible to prevent the concentration of the humidifying fluid L1a filled in the humidifying chamber 55 from remaining higher than the concentration of the humidifying fluid L1a contained in the humidifying fluid storage unit 61. More specifically, even if the amount of moisture contained in the humidifying fluid L1a filled in the humidifying chamber 55 decreases, the amount of moisture can be returned to an amount close to the amount at the time of shipment at an appropriate timing. This makes it possible to prevent ejection defects caused by insufficient humidification of the opening of the nozzle 22.

As described above, the outlet 55b of one of the multiple unit caps 51a is connected to the inlet 55a of another unit cap 51a adjacent to the unit cap 51a, the inlet 55a located most upstream is connected to the supply flow path 62a, and the outlet 55b located most downstream is connected to the recovery flow path 62b. This makes it possible to agitate the humidification fluid L1a in the circulation path 62 including the humidification chambers 55 of the multiple unit caps 51a using only one supply flow path 62a and recovery flow path 62b. Furthermore, it is possible to make the concentration of the humidification fluid L1a in the circulation path 62 including the humidification chambers 55 of the multiple unit caps 51a uniform using only one supply flow path 62a and recovery flow path 62b.

The capping device 50 humidifies the space SP with the moisture contained in the humidifying fluid L1a filled in the humidifying chamber 55, and periodically performs a circulation operation, thereby reducing the volume of the humidifying fluid L1a contained in the humidifying fluid storage section 61 by the amount of evaporated moisture. The humidifying fluid storage section 61 has a detection section 61a that detects the liquid level in the humidifying fluid storage section 61, so that it is possible to determine that the concentration of the humidifying fluid L1a has become greater than a predetermined concentration.

During the circulation operation, when the liquid level in the humidifying fluid storage section 61 is detected by the detection section 61a to be below the first predetermined height H1, it is determined that the concentration of the humidifying fluid L1a in the circulation path 62 has become greater than the predetermined concentration, and the concentration adjustment operation flow shown in Figure 16 is executed.

As shown in FIG. 15, by further providing a moisture supply unit 66 capable of supplying moisture within the circulation path 62, when moisture evaporates from the humidifying fluid L1a, the humidifying fluid L1a can be replenished with moisture L1b to optimize the concentration of the humidifying fluid L1a. In other words, the amount of moisture contained in the humidifying fluid L1a can be returned to the amount of moisture at the time of shipment.

The pressure loss in the flow path on the moisture supply unit 66 side is set to be equal to or greater than the pressure loss in the flow path on the humidifying fluid storage unit 61 side. This slows down the rate of change of the liquid level in the humidifying fluid storage unit 61, reducing the variation in liquid level detection, allowing the liquid level to be detected in a timely manner.

When performing concentration adjustment operation when the detection unit 61a detects that the liquid level in the humidifying fluid storage unit 61 is below the first predetermined height H1, the capping device 50 supplies moisture in the moisture storage unit 66a into the circulation path 62 until the liquid level is detected to be equal to or higher than the first predetermined height H1. The capping device 50 then causes the humidifying fluid L1a to flow in the circulation path 62. This allows the concentration of the humidifying fluid L1a to be optimized by replenishing the humidifying fluid L1a with the moisture that has evaporated and then circulating the humidifying fluid L1a in the circulation path 62.

When the detection unit 61a detects that the liquid level in the humidifying fluid storage unit 61 exceeds the first predetermined height H1 during the concentration adjustment operation, the capping device 50 closes the first opening/closing valve 66c and performs the circulation operation described above. In other words, when the concentration adjustment operation is performed, the circulation operation is performed before the concentration adjustment operation is completed. This causes the humidifying fluid L1a in the circulation path 62 to be agitated, so that the concentration of the humidifying fluid L1a throughout the circulation path 62 can be made uniform even when the concentration adjustment operation is performed.

The cap device 50 replenishes the humidified fluid L1a in the circulation path 62 with the evaporated moisture, thereby increasing the volume of the humidified fluid L1a in the circulation path 62. In addition, the second moisture permeable membrane 61e provided at the connection between the humidified fluid storage section 61 and the second atmosphere communication passage 61d allows gas to pass between the humidified fluid storage section 61 and the second atmosphere communication passage 61d. This allows air of the same volume as the increased volume of the humidified fluid L1a to flow from the humidified fluid storage section 61 to the second atmosphere communication passage 61d along with the increase in the volume of the humidified fluid L1a. Therefore, the circulation path 62
This makes it easier to replenish moisture to the humidifying fluid L1a inside the second moisture permeable membrane 61e. In addition, by making the area of the second moisture permeable membrane 61e larger than the volume of the humidifying fluid storage portion 61, the amount of air flowing out to the atmosphere from the second atmosphere communication passage 61d can be increased. Therefore, the evaporated moisture can be efficiently replenished to the humidifying fluid L1a.

As shown in FIG. 15, the capping device 50 performs a concentration adjustment operation including supplying moisture L1b into the circulation path 62 by the moisture supply unit 66 and flowing the humidification fluid L1a in the circulation path 62. The capping device 50 also performs a concentration adjustment operation including opening the first opening/closing valve 66c when supplying moisture L1b in the moisture storage unit 66a into the circulation path 62, and closing the first opening/closing valve 66c when flowing the humidification fluid L1a in the circulation path 62. Depending on the state of the first opening/closing valve 66c, it is possible to supply the evaporated moisture into the circulation path 62 and flow the humidification fluid L1a in the circulation path 62 as necessary. As a result, the concentration of the humidification fluid L1a can be optimized by replenishing the evaporated moisture to the humidification fluid L1a and then circulating the humidification fluid L1a in the circulation path 62.

In the liquid ejection device 11, when recording on the medium M is repeated using the liquid ejection head 21, the seal portion 56e of the unit cap 51a may lose adhesion to the nozzle surface 23 due to deterioration or fatigue caused by repeated stress over a long period of time. Also, a malfunction may occur in the components that make up the cap unit 51. In such a case, the cap unit 51 that has been used until then is replaced with a new cap unit 51. The cap unit 51 may be configured so that the unit caps 51a are replaced one by one.

As shown in FIG. 17, when the cap unit 51 is replaced, a cap replacement preparation operation is performed. Pressurized air is supplied from the pressurized air supply unit 67 into the unit cap 51a, and the humidified fluid L1a in the unit cap 51a is discharged to the humidified fluid storage unit 61. This allows the humidified fluid L1a in the unit cap 51a to be discharged outside the unit cap 51a. Furthermore, the humidified fluid L1a in the unit cap 51a can be recovered in the humidified fluid storage unit 61. In other words, the humidified fluid L1a in the cap unit 51 that has been used until now can be used as the humidified fluid L1a in the cap unit 51 that will be used from now on.

The cap device 50 may have an air supply unit that supplies air to the circulation path 62, between a first junction 62c where the moisture supply unit 66 and the circulation path 62 join, and the inlet 55a of the unit cap 51a, in the circulation path 62 through which the humidifying fluid L1a flows. The cap device 50 may further have a pump that sends the air to the circulation path 62. This allows the humidifying fluid L1a in the unit cap 51a to be discharged outside the unit cap 51a. Furthermore, the humidifying fluid L1a in the unit cap 51a can be collected in the humidifying fluid storage unit 61.

As shown in FIG. 7, the humidification chamber 55 is formed as a single flow path that connects the inlet 55a and the outlet 55b by the groove 55c and the first moisture permeable membrane 54 that covers the groove 55c. Therefore, in the cap replacement preparation operation, by supplying pressurized air to the inlet 55a of the single flow path in the humidification chamber 55, it is possible to easily discharge the humidification fluid L1a from the outlet 55b in the humidification chamber 55.

As described above, the outlet 55b of one of the multiple unit caps 51a is connected to the inlet 55a of another unit cap 51a adjacent to that unit cap 51a, the inlet 55a located most upstream is connected to the supply flow path 62a, and the outlet 55b located most downstream is connected to the recovery flow path 62b. This makes it possible to discharge the humidification fluid L1a in the humidification chambers 55 of the multiple unit caps 51a by the cap replacement preparation operation using one supply flow path 62a, one recovery flow path 62b, and one pressurized air supply unit 67.

As shown in FIG. 17, the humidified fluid storage unit 61 has a second atmosphere communication passage 61d. The second atmosphere communication passage 61d connects the humidified fluid storage unit 61 to the atmosphere through a labyrinth-like thin tube structure. Even when pressurized air is supplied to the humidified fluid storage unit 61 during the cap replacement preparation operation, the labyrinth-like thin tube structure of the second atmosphere communication passage 61d can prevent the outflow of humidified fluid L1a from the humidified fluid storage unit 61 to the outside of the humidified fluid storage unit 61 through the second atmosphere communication passage 61d.

As shown in FIG. 17, the humidified fluid storage section 61 has a second moisture permeable membrane 61e. The second moisture permeable membrane 61e allows gas to pass through while restricting the passage of liquid. Even when pressurized air is supplied into the humidified fluid storage section 61 during the cap replacement preparation operation, the outflow of humidified fluid L1a from the humidified fluid storage section 61 to the outside of the humidified fluid storage section 61 through the second atmosphere communication passage 61d can be suppressed.

When the cap unit 51 that has been used is replaced with a new cap unit 51 and before recording is performed on the medium M for the first time, the above-mentioned circulation operation is performed and the humidification chamber 55 of the unit cap 51a of the new cap unit 51 is filled with humidification fluid L1a. As a result, even in the replaced cap unit 51, the space SP surrounding the opening of the nozzle 22 when the unit cap 51a comes into contact with the liquid ejection head 21 is humidified, so that the opening of the nozzle 22 can be humidified.

In the liquid ejection device 11, even in the replaced cap unit 51, the space SP surrounding the opening of the nozzle 22 when the unit cap 51a comes into contact with the liquid ejection head 21 is humidified, thereby using the moisture in the humidifying fluid L1a. The used moisture is replenished from the moisture storage section 66a into the humidifying fluid L1a during the concentration adjustment operation. In other words, even in the replaced cap unit 51, the opening of the nozzle 22 of the liquid ejection head 21 can be humidified without refilling the circulation path 62 with new humidifying fluid L1a.

As shown in FIG. 15, during the concentration adjustment operation, when the first pump 63 is driven for a third predetermined time T3 and the liquid level in the humidifying fluid storage unit 61 is detected by the detection unit 61a to be below the first predetermined level H1, the control unit 90 determines that the moisture in the moisture storage unit 66a has run out. Since the humidifying fluid storage unit 61 has the detection unit 61a that detects the liquid level in the humidifying fluid storage unit 61, it is possible to detect that the amount of moisture in the moisture storage unit 66a has reached an amount at which it is determined that replacement of the moisture storage unit 66a is necessary.

When the amount of moisture in the moisture storage unit 66a used to humidify the opening of the nozzle 22 reaches an amount at which it is determined that the moisture storage unit 66a needs to be replaced, the moisture storage unit 66a that has been used until now is replaced with a full moisture storage unit 66a. However, if the user does not have a replacement moisture storage unit 66a, the opening of the nozzle 22 cannot be humidified with the humidifying fluid L1a until a replacement moisture storage unit 66a arrives at the user's hand. Also, if the moisture storage unit 66a is configured so that it cannot be replaced by the user, the opening of the nozzle 22 cannot be humidified with the humidifying fluid L1a until the moisture storage unit 66a is replaced by a service technician.

Until the moisture storage unit 66a is replaced, the first parameter table for flushing is switched to the second parameter table when the moisture L1b in the moisture storage unit 66a is depleted. This causes the opening of the nozzle 22 to be humidified by flushing. That is,
Until the moisture storage portion 66a is replaced, the space SP can be humidified by performing idle ejection from the liquid ejection head 21 into the unit cap 51a, allowing the user to continue printing operations.

As shown in FIG. 19, when the moisture storage section 66a is replaced, a cap replacement preparation operation is performed. By supplying pressurized air from the pressurized air supply section 67 into the unit cap 51a, the humidified fluid L1a in the unit cap 51a is discharged to the humidified fluid storage section 61 and the pressurized air is supplied into the unit cap 51a. This allows the humidified fluid L1a in the unit cap 51a to be discharged.

As shown in FIG. 9, the recess 57 has an absorber 53 capable of absorbing liquid at a position in contact with the first moisture permeable membrane 54. Because the amount of waste liquid L2 discharged into the unit cap 51a increases due to flushing or cleaning, a larger amount of waste liquid L2 than usual is absorbed by the absorber 53. The waste liquid L2 absorbed by the absorber 53 spreads throughout the entire absorber 53. The large amount of waste liquid L2 absorbed by the absorber 53 can more effectively humidify the space SP until the moisture storage section 66a is replaced. This can more effectively humidify the opening of the nozzle 22 of the liquid ejection head 21.

As in this embodiment, even when the humidification chamber 55 is provided at an angle to the horizontal, the waste liquid L2 absorbed by the absorber 53 spreads throughout the entire absorber 53. In other words, by the absorber 53 absorbing the waste liquid L2, the effect of the bias of the waste liquid L2 in the recess 57 due to gravity can be suppressed. This makes it possible to more uniformly humidify the entire space SP, even when the humidification chamber 55 is provided at an angle to the horizontal. And, the openings of the multiple nozzles 22 of the liquid ejection head 21 can be more uniformly humidified.

The absorbent body 53 is located in a position where it contacts the first moisture permeable membrane 54. Therefore, the position of the absorbent body 53 can be restricted by restricting only the surface of the absorbent body 53 that is not in contact with the first moisture permeable membrane 54 with the restricting member 52.

The sealing portion 56e is made of a material that repels the liquid ejected from the liquid ejection head 21, so that even when the amount of waste liquid L2 discharged into the unit cap 51a increases due to flushing or cleaning, the liquid in the unit cap 51a can be prevented from dripping out of the unit cap 51a through the sealing portion 56e.

When the moisture storage section 66a is replaced, the second parameter table for flushing is returned to the normal first parameter table, and the concentration adjustment operation is performed. The amount of waste liquid L2 discharged into the unit cap 51a increases only during the period until the moisture storage section 66a is replaced, so the amount of liquid used by flushing can be reduced.

As described above, the cap device 50 includes a unit cap 51a having a recess 57 that forms the space SP, a humidification chamber 55, and a first moisture permeable membrane 54. The recess 57 further includes a discharge hole 56b, so that one unit cap 51a can receive and discharge liquid discharged from the nozzle 22 and humidify the nozzle 22 as necessary. The humidification fluid L1a is circulated in the circulation path 62 while replenishing the humidification fluid L1a with the evaporated moisture, thereby stirring the humidification fluid L1a and optimizing its concentration. In other words, the humidification fluid L1a throughout the circulation path 62 can be maintained in a state suitable for humidifying the nozzle 22 of the liquid ejection head 21.

The effects of this embodiment will be described.
(1) The cap device 50 includes a unit cap 51a having a recess 57 that forms a space SP when the unit cap 51a contacts the liquid ejection head 21, a humidification chamber 55 through which the humidification fluid L1a flows, and a first moisture permeable film 54 having gas permeability that separates the recess 57 and the humidification chamber 55. The recess 57 has a discharge hole 56b that can discharge waste liquid L2 discharged from the nozzle 22 of the liquid ejection head 21 into the unit cap 51a. Moisture evaporated from the humidification fluid L1a in the humidification chamber 55 passes through the first moisture permeable film 54 and reaches the recess 57, so that the space SP formed by the recess 57 is humidified, and the opening of the nozzle 22 is humidified. In addition, the waste liquid L2 discharged into the unit cap 51a is not allowed to flow into the humidification chamber 55 by the first moisture permeable film 54, so that it is discharged from the discharge hole 56b in the recess 57 to the outside of the unit cap 51a. As a result, one unit cap 51a can receive and discharge the waste liquid L2 discharged from the nozzle 22, and humidify the nozzle 22. In other words, in the liquid ejection device 11, the space required to accommodate both the cap of the capping mechanism that prevents clogging of the nozzle 22 and the cap of the capping device that prevents the nozzle 22 from drying out can be reduced to the space required to accommodate only one of the caps. This makes it possible to prevent the liquid ejection device 11 from becoming larger.

(2) The discharge hole 56b is provided in the recess 57 at a position lower than the first moisture permeable membrane 54. The waste liquid L2 in the recess 57 can be discharged from the discharge hole 56b to the outside of the unit cap 51a by gravity. This makes it possible to reduce the amount of waste liquid L2 remaining in the recess 57. In addition, by blocking the surface of the first moisture permeable membrane 54 with the waste liquid L2, it is possible to prevent the moisture evaporated from the humidification fluid L1a in the humidification chamber 55 from being unable to pass through the first moisture permeable membrane 54. In other words, it is possible to prevent the opening of the nozzle 22 of the liquid ejection head 21 from being unable to be humidified.

(3) The drain hole 56b is provided at the bottom of the recess 57. The waste liquid L2 in the recess 57 can be discharged from the drain hole 56b to the outside of the unit cap 51a by gravity. This makes it possible to prevent the waste liquid L2 from remaining in the recess 57.

(4) The recess 57 has an absorbent 53 capable of absorbing liquid at a position in contact with the first moisture permeable membrane 54. The waste liquid L2 discharged into the recess 57 is absorbed by the absorbent 53. In addition, the moisture that evaporates from the humidifying fluid L1a and passes through the first moisture permeable membrane 54 humidifies the waste liquid L2 absorbed in the absorbent 53. The waste liquid L2 absorbed in the absorbent 53 spreads throughout the absorbent 53. This allows the distribution of the waste liquid L2 absorbed in the absorbent 53 to approach uniformity. In other words, the entire space SP can be more uniformly humidified. And the openings of the multiple nozzles 22 of the liquid ejection head 21 can be more uniformly humidified.

(5) The humidification chamber 55 has a groove 55c through which the humidification fluid L1a flows. The humidification chamber 55 is formed in a flow path shape that connects the inlet 55a and the outlet 55b by the groove 55c and the first moisture permeable membrane 54 that covers the groove 55c. By flowing the humidification fluid L1a in the humidification chamber 55, which is formed in a single flow path shape that connects the inlet 55a and the outlet 55b, the humidification fluid L1a can be filled into the humidification chamber 55 or discharged from the humidification chamber 55 as needed. Furthermore, since the humidification chamber 55 is formed in such a flow path shape, it is possible to prevent the humidification fluid L1a filled in the humidification chamber 55 from flowing out of the humidification chamber 55 unnecessarily. In addition, since the flow path is routed around the entire bottom surface of the unit cap 51a, the entire inside of the recess 57 can be humidified. This allows the openings of the multiple nozzles 22 of the liquid ejection head 21 to be more uniformly humidified.

(6) The humidification chamber 55 is provided at an angle to the horizontal, and the inlet 55a and outlet 55b are provided above the vertical center of the humidification chamber 55. This makes it possible to prevent the humidification fluid L1a filled in the humidification chamber 55 from flowing out of the humidification chamber 55 from the inlet 55a or outlet 55b due to head pressure.

(7) The recess 57 has an atmosphere communication hole 56a for connecting the space SP to the atmosphere, and the atmosphere communication hole 56a is provided above the vertical center of the recess 57. This prevents the atmosphere communication hole 56a from being blocked by the waste liquid L2, making it impossible to discharge the waste liquid L2 from within the recess 57.

(8) The capping device 50 further includes a humidifying fluid storage section 61, a supply flow path 62a, a recovery flow path 62b, and a first pump 63 capable of moving the humidifying fluid L1a through the circulation path 62. This allows the humidifying fluid L1a in the circulation path 62 to be stirred. To humidify the space SP, a large amount of moisture evaporates from the humidifying fluid L1a filled in the humidifying chamber 55. Therefore, by stirring the humidifying fluid L1a in the circulation path 62, the concentration of the humidifying fluid L1a throughout the circulation path 62 can be made uniform. In other words, the amount of moisture contained in the humidifying fluid L1a filled in the humidifying chamber 55 can be returned to an amount close to the amount at the time the liquid ejection device 11 was shipped.

(9) The capping device 50 further includes a moisture supplying section 66 capable of supplying moisture into the circulation path 62. As a result, when moisture evaporates from the humidifying fluid L1a, the humidifying fluid L1a can be replenished with moisture L1b to optimize the concentration of the humidifying fluid L1a. In other words, the amount of moisture contained in the humidifying fluid L1a can be returned to the amount at the time the liquid ejection device was shipped.

(10) The cap device 50 is configured with a plurality of unit caps 51a arranged side by side. The outlet 55b of one of the plurality of unit caps 51a is connected to the inlet 55a of another unit cap 51a adjacent to that unit cap 51a. The inlet 55a located most upstream is connected to the supply flow path 62a, and the outlet 55b located most downstream is connected to the recovery flow path 62b. This allows the humidification fluid L1a to be filled, stirred, and discharged from the plurality of unit caps 51a using only one supply flow path 62a and recovery flow path 62b.

(11) The maintenance method for the capping device 50 involves performing a concentration adjustment operation that includes supplying moisture into the circulation path 62 by the moisture supply unit 66 and flowing the humidifying fluid L1a within the circulation path 62. This allows the concentration of the humidifying fluid L1a to be optimized by replenishing the humidifying fluid L1a with the amount of moisture that has evaporated and then circulating the humidifying fluid L1a within the circulation path 62. In other words, the humidifying fluid L1a throughout the circulation path 62 can be maintained in a state suitable for humidifying the nozzles 22 of the liquid ejection head 21.

(12) The maintenance method of the cap device 50 performs a concentration adjustment operation that includes opening the first on-off valve 66c when supplying moisture from the moisture storage section 66a into the circulation path 62, and closing the first on-off valve 66c when flowing the humidifying fluid L1a in the circulation path 62. Depending on the state of the first on-off valve 66c, it is possible to supply the evaporated moisture into the circulation path 62 and flow the humidifying fluid L1a in the circulation path 62 as necessary. As a result, the concentration of the humidifying fluid L1a can be optimized by replenishing the evaporated moisture to the humidifying fluid L1a and then circulating the humidifying fluid L1a in the circulation path 62. In other words, the humidifying fluid L1a throughout the circulation path 62 can be maintained in a state suitable for humidifying the nozzles 22 of the liquid ejection head 21.

(13) In the maintenance method of the cap device 50, when replacing the unit cap 51a, pressurized air is supplied from the pressurized air supply unit 67 into the unit cap 51a, thereby performing a cap replacement preparation operation in which the humidified fluid L1a in the unit cap 51a is discharged to the humidified fluid storage unit 61 and the pressurized air is supplied into the unit cap 51a. This allows the humidified fluid L1a in the unit cap 51a to be discharged outside the unit cap 51a. Furthermore, the humidified fluid L1a in the unit cap 51a can be collected in the humidified fluid storage unit 61. That is, the humidified fluid L1a in the cap unit 51 that has been used until then can be used as the humidified fluid L1a in the cap unit 51 that will be used from now on. The cap unit 51 after replacement can also humidify the opening of the nozzle 22 of the liquid ejection head 21.

(14) The maintenance method for the cap device 50 includes the above-mentioned cap replacement preparation operation and a moisture storage unit pre-replacement operation that includes humidifying the nozzles 22 by performing idle ejection, which is the ejection of liquid unrelated to printing, from the liquid ejection head 21 into the space SP in the unit cap 51a until the moisture storage unit 66a is replaced. This allows the humidifying fluid L1a in the unit cap 51a to be discharged. Then, with the humidifying fluid L1a in the unit cap 51a having been discharged, the liquid ejection head 21 can perform idle ejection into the unit cap 51a to humidify the space SP. This allows the user to continue printing operations.

(15) In the maintenance method of the capping device 50, when the liquid level in the humidifying fluid storage section 61 is detected to be below the first predetermined height H1 and a concentration adjustment operation is performed, moisture in the moisture storage section 66a is supplied into the circulation path 62 until the liquid level is detected to be equal to or higher than the first predetermined height H1, and then the humidifying fluid L1a is caused to flow in the circulation path 62. This makes it possible to optimize the concentration of the humidifying fluid L1a by replenishing the humidifying fluid L1a with the moisture that has evaporated and then circulating the humidifying fluid L1a in the circulation path 62. In other words, the humidifying fluid L1a throughout the circulation path 62 can be maintained in a state suitable for humidifying the nozzles 22 of the liquid ejection head 21.

This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.
The capping device 50 may be provided in a liquid ejection device that ejects liquid vertically from the liquid ejection head 21 toward the medium M. In addition, the contact surface 56f that comes into contact with the nozzle surface 23 of the liquid ejection head 21 during capping, the absorber 53, the first moisture permeable film 54, and the humidification chamber 55 of the unit cap 51a may be provided in a horizontal state. That is, the unit cap 51a of this embodiment may be provided in a horizontal state in a liquid ejection device that ejects liquid vertically from the liquid ejection head 21 toward the medium M. Furthermore, the absorber 53, the first moisture permeable film 54, and the humidification chamber 55 may be provided in a state inclined with respect to the horizontal as in this embodiment, and only the contact surface 56f may be provided in a horizontal state.

The angle at which the humidification chamber 55 is inclined relative to the horizontal does not have to be the same as the angle at which the nozzle surface 23 on which the nozzles 22 of the liquid ejection head 21 are arranged is inclined relative to the horizontal. The angle at which the humidification chamber 55 is inclined relative to the horizontal may be greater or smaller than the angle at which the nozzle surface 23 is inclined relative to the horizontal.

The capping device 50 may be provided in a liquid ejection device that is a serial type inkjet printer that performs printing by ejecting liquid toward a medium M with a liquid ejection head supported by a carriage that moves back and forth in the width direction X. When the reciprocating carriage moves in the width direction X from an ejection area where printing is performed on the medium M to a maintenance area outside the ejection area for maintenance, the cap of the capping device 50 arranged in the maintenance area may cap the nozzle surface of the liquid ejection head. In this case, the capping device 50 may be configured such that when the carriage moves to the maintenance area and the liquid ejection head is located at the maintenance position, the cap moves in a direction approaching the nozzle surface of the liquid ejection head and the cap comes into close contact with the nozzle surface, thereby performing capping. In this way, even in a serial type liquid ejection device, one cap can receive and eject waste liquid discharged from the nozzles and humidify the nozzles. And,
Even in a serial type liquid ejection device, the space required to accommodate both the cap of the capping mechanism that prevents the nozzles from clogging and the cap of the capping device that prevents the nozzles from drying out is the same as the space required to accommodate only one of the caps. This makes it possible to prevent the serial type liquid ejection device 11 from becoming large.

The cap device 50 may have multiple unit caps 51a, or may have only one unit cap 51a. When the cap device 50 has only one unit cap 51a, the unit cap 51a may have one restricting member 52, one absorbent 53, one first moisture permeable membrane 54, one humidification chamber 55, and one case 56.

- As in the above embodiment, in the case of a line-type inkjet printer using a liquid ejection head 21 composed of five unit ejection heads 21a, the capping device 50 may have only one unit cap 51a. Also, in the above-mentioned serial-type liquid ejection device, the capping device 50 may have only one unit cap 51a.

The cap device 50 does not have to have the same number of regulating members 52, absorbers 53, first moisture permeable membranes 54, and humidification chambers 55. For example, the cap device 50 may have only one unit cap 51a, and the unit cap 51a may have one regulating member 52, one absorber 53, one first moisture permeable membrane 54, and multiple humidification chambers 55. The cap device 50 may also have multiple unit caps 51a, and each of the multiple unit caps 51a may have one regulating member 52, one absorber 53, one first moisture permeable membrane 54, and multiple humidification chambers 55.

The unit cap 51 a may have a plurality of recesses 57 .
The recess 57 may have a plurality of discharge holes 56b.
The recess 57 may have a plurality of atmosphere communication holes 56a.

- When the cap device 50 has multiple unit caps 51a, the recesses 57 of each unit cap 51a may be configured so that the spaces SP formed by the recesses 57 communicate with each other without passing through the discharge hole 56b. For example, the unit caps 51a may be configured so that the bottom of one unit cap 51a communicates with the bottom of another unit cap 51a adjacent to that unit cap 51a inside the cap unit 51. In that case, the number of discharge holes 56b in the cap unit 51 may be one.

The absorbent body 53 does not have to be in contact with the first moisture permeable membrane 54. For example, the position of the surface on the -Y1 side of the absorbent body 53 may be restricted by a restricting member other than the restricting member 52 that restricts the position of the surface on the +Y1 side of the absorbent body 53, and a space may be provided between the first moisture permeable membrane 54 and the absorbent body 53.

- In the above embodiment, the flow path of the humidification chamber 55 is formed in a maze shape with one path from the inlet 55a to the outlet 55b, but it may be two paths or three paths. The flow path only needs to be connected from the inlet 55a to the outlet 55b.

- The arrangement of the unit ejection heads 21a constituting the liquid ejection head 21 can be changed as appropriate. It is not limited to the configuration in which the unit ejection heads 21a are arranged diagonally as in the above embodiment, but may be, for example, a configuration in which the unit ejection heads 21a are arranged in two rows at a fixed interval in the width direction X, and are arranged in a staggered arrangement in which the positions of the rows are shifted in the width direction by half the interval between the rows.

In the above embodiment, the supply flow path 62a in the circulation path 62 is provided with the moisture supply unit 66 capable of supplying moisture, but the recovery flow path 62b in the circulation path 62 may also be provided with the moisture supply unit 66. In that case, the capping device 50 may further include a pump for supplying moisture to the recovery flow path 62b.

- In the above embodiment, the third opening/closing valve 58b, which connects the space SP to the atmosphere, is opened and closed by the movement of the cap unit 51. An actuator-type opening/closing valve that can be opened and closed by the control unit 90 regardless of the position of the cap unit 51 may be provided in the first atmosphere communication passage 58a.

The capping device 50 may have a second detection unit that detects the amount of moisture L1b in the moisture storage unit 66a. Based on the detection result of the second detection unit, the control unit 90 may determine whether the amount of moisture L1b in the moisture storage unit 66a has reached an amount that requires replacement of the moisture storage unit.

The capping device 50 may be configured so that the moisture in the moisture storage portion 66a can be replenished. The capping device 50 may be configured so that the humidification fluid storage portion 61 can be replaced.
The timing at which the circulation operation is performed may be changed by an administrator or a user.

- The first predetermined time T1, the second predetermined time T2, the third predetermined time T3, and the fourth predetermined time T4 do not have to be constant. The values may be changed depending on the temperature and humidity environment. In addition, the values may be changed by an administrator or a user.

The liquid ejection device 11 may have a third parameter table as a flushing parameter table, which ejects an even larger amount of liquid. When the time interval during which the concentration adjustment operation was performed is short, the control unit 90 may switch to the third parameter table when switching the flushing table in the operation before replacing the moisture storage unit. In other words, the liquid ejection device 11 may have multiple parameter tables with different amounts of liquid ejected as a flushing parameter table. When switching the flushing table in the operation before replacing the moisture storage unit, the control unit 90 may switch to an appropriate parameter table from among the multiple parameter tables depending on the time interval during which the concentration adjustment operation was performed.

The liquid ejection device 11 may be a liquid ejection device that ejects or ejects liquids other than ink. The state of the liquid ejected from the liquid ejection device as minute droplets includes granular, teardrop, and thread-like tails. The liquid here may be any material that can be ejected from the liquid ejection device. For example, the liquid may be any state in which the substance is in the liquid phase, and may include liquids with high or low viscosity, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and metal melts. The liquid may include not only liquids as one state of matter, but also particles of functional materials made of solids such as pigments and metal particles dissolved, dispersed, or mixed in a solvent. Representative examples of liquids include inks and liquid crystals as described in the above embodiments.

The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below.
(A) A capping device is a capping device capable of forming a space surrounding the opening of a nozzle when it comes into contact with a liquid ejection head having a nozzle that ejects liquid, and includes a cap having a recess that forms the space, a humidification chamber having an inlet through which humidification fluid flows in to humidify the space, and an outlet through which the humidification fluid flows out, and a gas-permeable partition that separates the recess from the humidification chamber, and the recess has a hole through which liquid ejected from the liquid ejection head into the cap can be discharged.

According to this configuration, moisture evaporated from the humidifying fluid in the humidifying chamber passes through the partition and reaches the recess, humidifying the space formed by the recess and humidifying the nozzle opening of the liquid ejection head. In addition, liquid discharged into the cap is prevented from flowing into the humidifying chamber by the partition, and is discharged outside the cap through a hole in the recess. This allows a single cap to receive and discharge liquid discharged from the nozzle and humidify the nozzle. In other words, in a liquid ejection device, the space required to accommodate both the cap of the capping mechanism that prevents nozzle clogging and the cap of the capping device that prevents the nozzle from drying out is the same as the space required to accommodate only one of the caps. This makes it possible to prevent the liquid ejection device from becoming too large.

(B) In the capping device, the hole may be provided in the recess at a position lower than the partition wall.
According to this configuration, the liquid in the recess can be discharged to the outside of the cap through the hole by gravity. This makes it possible to reduce the amount of liquid remaining in the recess. Furthermore, by blocking the surface of the partition with liquid, it is possible to prevent the moisture evaporated from the humidification fluid in the humidification chamber from being unable to pass through the partition. In other words, it is possible to prevent the nozzle opening of the liquid ejection head from being unable to be humidified.

(C) In the capping device, the hole may be provided at the bottom of the recess.
According to this configuration, the liquid in the recess can be discharged to the outside of the cap through the hole by gravity, and the liquid can be prevented from remaining in the recess.

(D) In the above capping device, the recess may have an absorbent capable of absorbing liquid at a position where the recess contacts the partition wall.
According to this configuration, the liquid discharged into the recess is absorbed into the absorbent body. Furthermore, the moisture that evaporates from the humidifying fluid and passes through the partition humidifies the liquid absorbed into the absorbent body. The liquid absorbed into the absorbent body spreads throughout the absorbent body. This makes it possible to make the distribution of the liquid absorbed into the absorbent body more uniform. In other words, the entire space can be more uniformly humidified. Furthermore, the openings of the multiple nozzles in the liquid ejection head can be more uniformly humidified.

(E) In the above cap device, the humidification chamber may have a groove through which the humidification fluid flows, and the humidification chamber may be formed into a flow path that connects the inlet and the outlet by the groove and the partition wall that covers the groove.

According to this configuration, the humidifying fluid can be flowed in the humidifying chamber, which is formed in a flow path that connects the inlet and outlet, so that the humidifying fluid can be filled into the humidifying chamber or discharged from the humidifying chamber as needed. Furthermore, because the humidifying chamber is formed in a flow path, it is possible to prevent the humidifying fluid filled in the humidifying chamber from unnecessarily flowing out of the humidifying chamber. In addition, because the flow path is routed around the entire bottom surface of the cap, the entire recess can be humidified. This allows the openings of the multiple nozzles in the liquid ejection head to be humidified more uniformly.

(F) In the above capping device, the humidification chamber may be arranged in an inclined position relative to the horizontal, and the inlet and the outlet may be arranged above the vertical center of the humidification chamber.

With this configuration, it is possible to prevent the humidification fluid filled in the humidification chamber from flowing out of the humidification chamber from the inlet or the outlet due to the hydraulic head pressure.
(G) In the above capping device, the recess may have an atmosphere vent hole for connecting the space to the atmosphere, and the atmosphere vent hole may be provided above the vertical center of the recess.

According to this configuration, it is possible to prevent the atmosphere communication hole from being blocked by liquid, which makes it impossible to discharge the liquid from inside the recess.
(H) The above-mentioned capping device may further include a humidifying fluid storage section that stores the humidifying fluid, a supply flow path that connects the humidifying fluid storage section to the inlet, a recovery flow path that connects the outlet to the humidifying fluid storage section, and a pump that can move the humidifying fluid within a circulation path that includes the humidifying fluid storage section, the supply flow path, and the recovery flow path.

This configuration allows the humidifying fluid in the circulation path to be agitated. To humidify the space, a large amount of moisture evaporates from the humidifying fluid filled in the humidifying chamber. Therefore, by agitating the humidifying fluid in the circulation path, the concentration of the humidifying fluid throughout the circulation path can be made uniform. In other words, the amount of moisture contained in the humidifying fluid filled in the humidifying chamber can be returned to an amount close to the amount when the liquid ejection device was shipped.

(I) The capping device may further include a moisture supply unit capable of supplying moisture into the circulation path.
According to this configuration, when moisture evaporates from the humidification fluid, moisture can be replenished to the humidification fluid to adjust the concentration of the humidification fluid, i.e., the amount of moisture contained in the humidification fluid can be returned to the amount at the time of shipment of the liquid ejection device.

(J) In the above capping device, the capping device may be configured with a plurality of caps arranged side by side, and the outlet of one of the plurality of caps may be connected to the inlet of a second cap adjacent to the first cap, the inlet located most upstream may be connected to the supply flow path, and the outlet located most downstream may be connected to the recovery flow path.

With this configuration, humidification fluid can be filled, stirred, and discharged from multiple caps using only one supply flow path and one recovery flow path.

11...liquid ejection device, 12...main body, 13...image reading unit, 14...automatic feed unit, 15...operation unit, 16...medium storage unit, 17...mounting unit, 17a...mounting surface, 19...transport path, 20...recording unit, 21...liquid ejection head, 21a...unit ejection head, 21b...nozzle row, 22...nozzle, 22a...opening, 23...nozzle surface, 24...head unit, 25...support unit, 40...wiper device, 41...wiper carriage, 42...wiper member, 43...waste liquid outlet, 50...cap device, 51...cap unit, 51a...unit cap as an example of a cap, 52...regulating member, 52a...regulating surface, 52b...communicating hole, 52c...positioning engaged portion, 53...absorber, 54...first moisture permeable membrane as an example of a partition, 54a... Communication part, 55... Humidification chamber, 55a... Inlet, 55b... Outlet, 55c... Groove, 55d... Positioning engagement part, 55e... Communication part, 55f... Communication hole, 55g... Engagement part, 55h... Positioning engagement part, 55i... Groove wall, 55j... Communication hole, 56... Case, 56a... Atmospheric communication hole, 56b... Discharge hole which is an example of hole, 56c ...Engaged part, 56d... Positioning engaged part, 5 6e...sealing portion, 56f...contact surface, 57...recess, 58...atmosphere release mechanism, 58a...first atmosphere communication passage, 58b...third opening/closing valve, 59...holding portion, 60...humidified fluid circulation mechanism, 61...humidified fluid storage portion, 61a...detection portion, 61b...first electrode, 61c...second electrode, 61d...second atmosphere communication passage, 61e...second moisture permeable membrane, 61f...inlet portion, 61g...outlet portion, 62...circulation Circulation path, 62a...supply flow path, 62b...recovery flow path, 62c...first junction, 62d...clamp section, 63...first pump which is an example of a pump, 64...first check valve, 65...pressure adjustment valve, 66...moisture supply section, 66a...moisture storage section, 66b...moisture supply flow path, 66c...first on-off valve which is an example of an on-off valve, 66d...second check valve, 66e...second junction, 66f... Outlet portion, 67...pressurized air supply portion, 68...humidification fluid pack, 68a...outlet portion, 69...clamp, 67a...pressurized air supply path, 67b...second on-off valve, 67c...second pump, 80...waste liquid recovery mechanism, 81...waste liquid recovery path, 81a...first waste liquid recovery path, 81b...second waste liquid recovery path, 82...third pump, 83...buffer chamber, 84...fourth pump, 85...third atmosphere Connecting passage, 86...waste liquid storage section, 90...control section, 91 detector group, 94...interface section, 95...CPU, 96...memory, 97...control circuit, 98...drive circuit, 99...computer, θ1...first predetermined angle, θ2...second predetermined angle, D1...first direction, D2...second direction, D3...third direction, D4...fourth direction, D5...fifth direction, D6...sixth direction, H1...first predetermined height which is an example of a predetermined height, H2...second predetermined height, L1a...humidifying fluid, L1b...moisture, L2...waste liquid, M...medium, P1...first predetermined pitch, SP...space, T1...first predetermined time, T2...second predetermined time, T3...third predetermined time, T4...fourth predetermined time, X...width direction, Y...depth direction, Y1...ejection direction, Z1...first transport direction, Z...vertical direction.

Claims (10)

A capping device capable of forming a space surrounding an opening of a nozzle when the capping device comes into contact with a liquid ejection head having a nozzle for ejecting liquid,
A recess forming the space;
a humidification chamber having an inlet through which a humidification fluid for humidifying the space flows and an outlet through which the humidification fluid flows out;
a partition wall that separates the recess and the humidification chamber;
The partition restricts the passage of liquid and has gas permeability;
The capping device according to claim 1, wherein the recess has a hole through which liquid discharged from the liquid ejection head into the cap can be discharged. The capping device according to claim 1 , wherein the hole is provided in the recess at a position lower than the partition wall. The capping device according to claim 2 , wherein the hole is provided at the bottom of the recess. 4. The capping device according to claim 1, wherein the recess has an absorbent capable of absorbing liquid at a position where the recess contacts the partition wall. the humidification chamber has a groove through which the humidification fluid flows,
5. The capping device according to claim 1, wherein the humidification chamber is formed in the shape of a flow passage that communicates the inlet and the outlet by the groove and the partition wall that covers the groove. The humidification chamber is provided at an inclination with respect to the horizontal,
6. The capping device according to claim 1, wherein the inlet and the outlet are provided above a vertical center of the humidification chamber. the recess has an air vent hole for connecting the space to the atmosphere,
7. The capping device according to claim 1, wherein the air vent is provided above a center of the recess in a vertical direction. a humidification fluid storage section for storing the humidification fluid;
a supply flow path communicating the humidification fluid storage portion with the inlet;
a recovery flow passage communicating the outlet with the humidification fluid storage section;
8. The capping device according to claim 1, further comprising: a pump capable of causing the humidification fluid to flow in a circulation path including the humidification fluid storage portion, the supply flow path, and the recovery flow path. 9. The method according to claim 8, further comprising: a moisture supply unit capable of supplying moisture into the circulation path.
The capping device according to claim 1 . The capping device is configured with a plurality of the caps arranged side by side,
Among the plurality of caps, the outlet of one cap is connected to the inlet of a second cap adjacent to the one cap,
10. The capping device according to claim 8, wherein the inlet located most upstream is connected to the supply flow path, and the outlet located most downstream is connected to the recovery flow path.