JP7589084B2 - Wiping Device - Google Patents

Description

The present invention relates to a wiping device that wipes the ink ejection surface of a nozzle row of an inkjet head.

Conventionally, in inkjet printing devices, ink aggregates may adhere to the ink ejection openings of the nozzles of the inkjet head, and dirt and dust such as paper powder generated from the paper may adhere to the ink ejection openings of the nozzles. When ink aggregates adhere to the ink ejection openings of the nozzles or paper powder accumulates, ejection defects such as disturbances in the ejection direction of ink from the nozzles or failure to eject ink may occur.

To reduce such ejection defects, a series of operations is known in which ink is forcibly ejected from the nozzles of the inkjet head, a process known as purging, and then the ink ejection openings of the nozzles are wiped with a wiper. This removes any ink that has solidified at the ink ejection openings of the nozzles, as well as any debris at the ink ejection openings of the nozzles.

Here, the wiping action described above can be used to remove dirt from the ink ejection ports, but this also results in the wiper itself becoming dirty.

Therefore, Patent Document 1 proposes a method of improving the foreign matter removal performance by providing a wiping member for removing foreign matter adhering to the wiper and keeping the wiping member wet with cleaning liquid.

JP 2013-154490 A

However, in the configuration described in Patent Document 1, the wiper 101 moves relative to the wiping member 100 as shown by the arrow in Figure 11, i.e., the movement trajectory of the tip of the wiper 11 is parallel to the contact surface of the wiper 101 with the wiping member 100, so the contact portion of the wiper with the wiping member is always the same. Therefore, the portion of the wiper that is deformed by being pressed against the wiping member is always in the same position, so there is a problem that the wiper is easily deteriorated by repeated wiping.

In addition, the configuration described in Patent Document 1 can only wipe the tip of the wiper, and cannot wipe the entire wiper. Therefore, dirt such as ink adhering to parts of the wiper other than the tip may flow down to the tip, and the inkjet head may be wiped with the tip of the wiper still dirty.

In view of the above circumstances, the present invention aims to provide a wiping device that can suppress deterioration of the wiper due to deformation and can widen the wiping range of the wiper.

The wiping device of the present invention includes a wiper that wipes an ink ejection surface on which the ink ejection openings of the nozzles of an inkjet head having a plurality of nozzles that eject ink are arranged, a wiping member that wipes off any deposits that have adhered to the wiper by contact with the wiper, and a moving mechanism that moves the wiper so that it comes into contact with the wiping member, and is configured so that the contact area between the wiper and the wiping member gradually increases as the wiper is moved by the moving mechanism.

The wiping device of the present invention is configured so that the contact area between the wiper and the wiping member gradually increases as the wiper is moved by the moving mechanism, thereby suppressing deterioration of the wiper due to deformation and widening the wiping range of the wiper.

FIG. 1 is a perspective view showing a schematic configuration of a wiping device according to an embodiment of the present invention; FIG. 2 is a perspective view showing the appearance of an inkjet head; Diagram showing the wiper configuration FIG. 2 is a block diagram showing a schematic configuration of a control system of the wiping device shown in FIG. FIG. 13 illustrates a state in which the wiper is placed at an initial wiping position. FIG. 13 is a diagram showing a state in which the wiper has reached the wiping member; FIG. 13 is a diagram showing how the contact area between the wiper and the wiping member gradually increases. A diagram showing the wiper immersed in the cleaning solution. A flowchart for explaining the operation of an embodiment of the wiping device of the present invention. FIG. 1 shows an example of a viscometer provided in a cleaning liquid tank. FIG. 1 is a diagram for explaining wiping by a wiper using a conventional wiping member;

One embodiment of the wiping device of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing the schematic configuration of the wiping device 1 of this embodiment. The wiping device 1 of this embodiment wipes the inkjet head 2 shown in FIG. 1, and first, the configuration of the inkjet head 2 that is the target of wiping will be described.

Figure 2 is a perspective view showing the appearance of the inkjet head 2. Note that in Figure 2, only the parts necessary for explaining the inkjet head 2 are shown in a simplified form. As shown in Figure 2, the inkjet head 2 comprises a nozzle plate 36 and a nozzle guard 32. The nozzle plate 36 has a nozzle row in which multiple ink ejection openings 37 of nozzles that eject ink are arranged.

2, the nozzle guard 32 has an opening 46 in a portion corresponding to the nozzle row of the nozzle plate 36, and the ink ejection surface 36a of the nozzle row is exposed at the opening 46. In this embodiment, the ink ejection surface 36a is the surface on which the openings of the ink ejection ports 37 of the nozzles are arranged, and is the same surface as the surface of the nozzle plate 36.

The nozzle guard 32 protects the ink ejection surface 36a of the nozzle plate 36. Specifically, the nozzle guard 32 has a bottom plate 44 formed to cover the periphery of the nozzle row, and a side wall 47 erected on the periphery of the bottom plate 44. The opening 46 described above is formed in the bottom plate 44.

The opening 46 is formed in a long, narrow rectangle in the front-to-rear direction so that the ink ejection ports 37 of all nozzles are exposed.

Although not shown in FIG. 2, ink is supplied to the inkjet head 2 from the ink supply pipe 2a shown in FIG. 1.

The wiping device 1 of this embodiment removes ink and dirt adhering to the outer surface of the nozzle guard 32 of the inkjet head 2 described above and the ink ejection surface 36a exposed at the opening 46 of the nozzle guard 32.

Next, we will explain the wiping device 1 of this embodiment shown in Figure 1.

As shown in FIG. 1, the wiping device 1 of this embodiment includes a wiping unit 10, a wiping member 30, and a cleaning liquid tank 40.

The wiping section 10 includes a wiper 11, a timing belt 12, and first to fourth belt conveying rollers 13 to 16.

As shown in FIG. 3, the wiper 11 is composed of a wiper body 11a and a wiper mounting member 11b. The wiper body 11a is made of a flexible and elastic material such as rubber, and is formed in a rectangular shape.

The wiper body 11a has a width equal to the width of the inkjet head 2 (the length in the direction perpendicular to the nozzle row) and is wide enough to wipe the outer surface of the nozzle guard 32 and the ink ejection surface 36a of the inkjet head 2 as described above.

The wiper body 11a is flexible, and when the tip of the wiper body 11a is pressed against the outer surface of the nozzle guard 32 of the inkjet head 2, the tip bends and is pressed against the outer surface of the nozzle guard 32 and the ink ejection surface 36a with a predetermined pressure by the elastic force of the wiper body 11a.

The wiper mounting member 11b is a member that attaches the wiper body 11a to the timing belt 12, and is formed, for example, from a metal. The wiper mounting member 11b is erected on the timing belt 12, and the wiper body 11a is attached to the wiper mounting member 11b using screws or the like.

The timing belt 12 is a circular belt that transports the wiper 11. As shown in FIG. 1, the timing belt 12 extends in the direction of the nozzle row of the inkjet head 2, and the wiper 11 is attached to the timing belt 12 so that the width direction of the timing belt 12 is parallel to the wiping surface of the wiper 11. As the timing belt 12 moves in the direction of the nozzle row of the inkjet head 2, the wiper 11 wipes the inkjet head 2.

The first to fourth belt transport rollers 13 to 16 are rollers around which the timing belt 12 is stretched. The first belt transport roller 13 and the second belt transport roller 14 are aligned in the direction of the nozzle row of the inkjet head 2, and are positioned at the same distance from the ink ejection surface 36a of the inkjet head 2. The distance between the first belt transport roller 13 and the second belt transport roller 14 is set to be longer than the length of the inkjet head 2 in the direction of the nozzle row. Therefore, the wiper 11 wipes the inkjet head 2 while it moves between the first belt transport roller 13 and the second belt transport roller 14.

The third belt conveyor roller 15 and the fourth belt conveyor roller 16 are positioned lower than the first belt conveyor roller 13 and the second belt conveyor roller 14 (at a position farther from the inkjet head 2). The third belt conveyor roller 15 is positioned directly below the first belt conveyor roller 13. The fourth belt conveyor roller 16 is positioned so that the distance between the third belt conveyor roller 15 and the fourth belt conveyor roller 16 is longer than the distance between the first belt conveyor roller 13 and the second belt conveyor roller 14. The fourth belt conveyor roller 16 is positioned higher than the third belt conveyor roller 15 (closer to the inkjet head 2).

As a result, the timing belt 12 between the third belt conveyor roller 15 and the fourth belt conveyor roller 16 is configured to have an inclination with respect to the timing belt 12 between the first belt conveyor roller 13 and the second belt conveyor roller 14. Therefore, when the wiper 11 moves between the third belt conveyor roller 15 and the fourth belt conveyor roller 16, the movement trajectory of its tip will have an inclination, and the inclination angle of the movement trajectory will be described in detail later. Note that the dashed dotted line in Figure 5 indicates the movement trajectory T of the tip of the wiper 11 when it is assumed that the tip of the wiper 11 is not bent.

The first to fourth belt conveyor rollers 13 to 16 are rotated by a drive motor 17 shown in FIG. 4.

The cleaning liquid tank 40 stores the cleaning liquid. The cleaning liquid tank 40 is formed in a substantially rectangular parallelepiped shape, and a recess 41 is formed in its central portion, in which the cleaning liquid is stored. The recess 41 of the cleaning liquid tank 40 has a first bottom 41a in which the cleaning liquid is stored, and a second bottom 41b in which the cleaning liquid is stored and in which the wiping member 30 is placed. A step surface 41c is formed between the first bottom 41a and the second bottom 41b, and the step surface 41c is formed so that the bottom surface of the second bottom 41b is lower than the bottom surface of the first bottom 41a.

The wiping member 30 is then positioned so that a portion of its end face abuts against the step surface 41c (see FIG. 5). This fixes the position of the wiping member 30 on the bottom surface of the recess 41 of the cleaning liquid tank 40.

The bottom surface of the second bottom portion 41b has an inclination that gradually decreases toward the first bottom portion 41a. This allows the wiping member 30 to fall toward the step surface 41c due to its own weight and come into contact with the step surface 41c.

In this embodiment, the wiping member 30 is formed as a rectangular parallelepiped, and is installed so that one surface thereof contacts the bottom surface of the second bottom portion 41b. Therefore, the contact surface where the wiper 11 contacts the wiping member 30 (the surface opposite to the surface that contacts the bottom surface of the second bottom portion 41b) is parallel to the bottom surface of the second bottom portion 41b, i.e., the contact surface of the wiping member 30 where the wiper 11 contacts also has an inclination.

The distance between the timing belt 12 between the third belt conveyor roller 15 and the fourth belt conveyor roller 16 and the wiping member 30 is set so that the wiper body 11a slides on the surface of the wiping member 30 when the wiper 11 passes above the wiping member 30.

As described above, the movement trajectory T of the tip of the wiper 11 when it moves between the third belt conveyor roller 15 and the fourth belt conveyor roller 16 has an incline, but the angle between the movement trajectory T and the contact surface of the wiper 11 with the wiping member 30 is set so that the contact area between the wiper 11 and the wiping member 30 gradually increases as the wiper 11 moves. The increase in the contact area in response to the movement of the wiper 11 will be described in detail later.

The side wall of the cleaning liquid tank 40 is formed with a supply hole 42 for supplying cleaning liquid into the recess 41. The bottom wall of the first bottom 41a is formed with a discharge hole 43 for discharging the cleaning liquid stored in the first bottom 41a. The cleaning liquid is supplied to the supply hole 42 from a supply unit 50 (see FIG. 4) described later. The cleaning liquid stored in the first bottom 41a and the second bottom 41b is discharged to the outside of the cleaning liquid tank 40 through the discharge hole 43 by a discharge unit 60 (see FIG. 4) described later.

Any known cleaning solution can be used.

As described above, the wiping member 30 is arranged so as to be immersed in the cleaning liquid in the cleaning liquid tank 40, and the wiper 11 comes into contact with it to wipe away ink and dirt adhering to the wiper 11. The wiping member 30 is formed from a material that is absorbent, flexible, and resilient, and for example, a foam material such as urethane is used.

As described above, the wiping member 30 has absorbency that allows it to absorb the cleaning liquid throughout its entire interior. In addition, the wiping member 30 has flexibility that allows it to deform so as not to apply more load than necessary to the wiper 11 when the wiper 11 comes into contact with it and slides. Furthermore, the wiping member 30 has restoring ability that allows it to return to its original shape when the wiper 11 has finished wiping. The wiping member 30 may be made of any material as long as it has the absorbency, flexibility, and restoring ability described above.

The wiping member 30 is installed on the second bottom 41b as described above, but is configured to be removable and replaceable.

Figure 4 is a block diagram showing the schematic configuration of the control system of the wiping device 1 of this embodiment. As shown in Figure 4, the wiping device 1 includes a control unit 70.

The control unit 70 controls the entire wiping device 1 and includes a CPU (Central Processing Unit) and a semiconductor memory. The control unit 70 controls the wiping unit 10, the supply unit 50, and the discharge unit 60 of the wiping device 1 by having the CPU execute a wiping operation program that is pre-stored in a storage medium such as a semiconductor memory or a hard disk.

The supply unit 50 supplies cleaning liquid to the supply hole 42 of the cleaning liquid tank 40 as described above under the control of the control unit 70. Specifically, the supply unit 50 includes a cleaning liquid tank, a supply pump, a supply valve, and piping (not shown), and the supply of cleaning liquid is controlled by controlling the supply pump and the supply valve.

The discharge unit 60 discharges the cleaning liquid from the discharge hole 43 of the cleaning liquid tank 40 as described above under the control of the control unit 70. Specifically, the discharge unit 60 includes a waste liquid tank, a discharge pump, a discharge valve, and piping (not shown), and the discharge of the cleaning liquid is controlled by controlling the discharge pump and the discharge valve.

The supply of cleaning liquid by the supply unit 50 and the discharge of cleaning liquid by the discharge unit 60 may be achieved by utilizing the pressure due to the head difference without using a pump.

In this embodiment, as shown in FIG. 5, a part of the wiping member 30 is immersed in the cleaning liquid L in the cleaning liquid tank 40, and the remaining part, including the contact surface of the wiper 11, is exposed from the liquid level S of the cleaning liquid L. That is, the cleaning liquid L is stored up to the liquid level S shown in FIG. 5, and most of the wiping member 30 is immersed in the cleaning liquid L, but a part including its surface (wiping surface) is located above the liquid level S of the cleaning liquid L and is not immersed in the cleaning liquid L. This makes it possible to prevent the ink and dirt wiped off by the wiping member 30 from flowing out into the cleaning liquid L, and reduces the frequency of replacing the cleaning liquid L. The surface of the wiping member 30 is in a wet state due to capillary action.

Next, the operation of the wiping device 1 in this embodiment will be described with reference to the flowcharts shown in Figures 5 to 8 and Figure 9.

First, when wiping the inkjet head 2, the inkjet head 2 or the wiping device 1 moves, and as shown in FIG. 5, the tip of the wiper 11 is positioned at one of the short sides of the opening 46 of the nozzle guard 32 of the inkjet head 2 (S10). This position is the initial wiping position.

Next, the control unit 70 operates the drive motor 17 to rotate the first to fourth belt conveyor rollers 13 to 16, thereby moving the timing belt 12, and thereby moving the wiper 11 in the direction of arrow A1 shown in FIG. 5 (S12). This movement of the wiper 11 wipes the nozzle guard 32 and the ink ejection surface 36a of the inkjet head 2 (S14).

Next, the control unit 70 rotates the first to fourth belt conveying rollers 13 to 16 to move the wiper 11 in the direction of arrow A2 shown in FIG. 5, and then moves it from the fourth belt conveying roller 16 to the third belt conveying roller 15 in the direction of arrow A3 shown in FIG. 6.

As shown in FIG. 6, after the wiper 11 moves to the wiping member 30, the wiper 11 (wiper body 11a) is pressed against the wiping member 30, and the wiper 11 moves in this state, causing the wiper 11 (wiper body 11a) to slide on the surface of the wiping member 30. As a result, the ink and dirt that has adhered to the wiper body 11a by the wiping action described above is wiped off by the wiping member 30 (S16).

In this embodiment, as described above, the angle between the movement trajectory T of the wiper 11 and the contact surface of the wiping member 30 with the wiper 11 is set so that the contact area between the wiper 11 and the wiping member 30 gradually increases as the wiper 11 moves. This makes it possible to change the contact area between the wiper 11 and the wiping member 30 with a simple configuration.

7A to 7C are diagrams showing how the contact area between the wiper 11 and the wiping member 30 gradually increases as the wiper 11 moves as described above. FIG. 7A is a diagram showing the state immediately before the wiper 11 is pressed against the wiping member 30. As shown in FIG. 7A, the movement trajectory T of the wiper 11 and the contact surface of the wiper 11 of the wiping member 30 are not parallel. In this embodiment, the angle between the movement trajectory T of the wiper 11 and the contact surface of the wiper 11 of the wiping member 30 is the same as the angle θ between the horizontal plane and the bottom surface of the wiping member 30 (the bottom surface of the second bottom portion 41b). It is preferable that the angle θ is set to an angle at which all of the contact parts between the wiper 11 and the inkjet head 2 can be wiped off by the wiping member 30. This allows dirt on the wiper 11 to be sufficiently wiped off.

When the wiper 11 moves, as shown in FIG. 7B, the tip of the wiper 11 is pressed against the wiping member 30 and deformed, the tip of the wiper 11 comes into contact with the wiping surface of the wiping member 30, and the ink adhering to the tip of the wiper 11 is wiped off by the wiping member 30.

Next, when the wiper 11 moves from the state shown in FIG. 7B to the state shown in FIG. 7C, the wiper 11 is pressed against the wiping member 30 up to the base of the wiper 11, causing it to deform, and the ink adhering to the base of the wiper 11 is also wiped off by the wiping member 30.

In this embodiment, as shown in Figures 7A to 7C, the contact area between the wiper 11 and the wiping member 30 is gradually increased as the wiper 11 moves, so that the deformed portion of the wiper 11 can be prevented from always being in the same position as in the conventional case, and deterioration due to deformation of the wiper 11 can be suppressed. In addition, the contact area of the wiper 11 with the wiping member 30 can be widened, so the wiping range of the wiper 11 can be widened. Furthermore, because the wiping range of the wiper 11 can be widened, an increase in the ink concentration of the cleaning liquid in the cleaning liquid tank 40 can be suppressed, and the wiper 11 can wipe the ink ejection surface 36a in a clean state.

Then, after passing through the wiping member 30, the wiper 11 is immersed in the cleaning liquid L stored in the first bottom 41a of the cleaning liquid tank 40 as shown in FIG. 8 (S18). This allows the cleaning liquid to adhere to the wiper 11.

In addition, in this embodiment, as described above, the wiper 11 is moved in the following order: wiping of the ink ejection surface 36a with the wiper 11, wiping of the wiper 11 with the wiping member 30, and immersion of the wiper 11 in the cleaning liquid L. Therefore, after the ink and dirt on the wiper 11 are wiped off with the wiping member 30, the wiper 11 can be immersed in the cleaning liquid L, and contamination of the cleaning liquid L can also be prevented.

Then, the control unit 70 stops the wiper 11 when the wiper 11 is immersed in the cleaning liquid L (S20). Next, the inkjet head 2 or the wiping device 1 moves, and the wiping device 1 is positioned away from the inkjet head 2 and enters a waiting state for the next wiping operation.

When wiping the inkjet head 2 again, the inkjet head 2 or the wiping device 1 moves, and as shown in FIG. 8, the wiper 11 moves in the direction of arrow A4 from the third belt conveyor roller 15 toward the first belt conveyor roller 13. The control unit 70 then moves the wiper 11 back to the initial wiping position and wipes the inkjet head 2.

In the wiping device 1 of the above embodiment, if a long period of time passes after the cleaning liquid is supplied to the cleaning liquid tank 40, the amount of cleaning liquid decreases due to drying and the viscosity increases. If the viscosity of the cleaning liquid increases in this way, the water repellency decreases and the cleaning ability of the wiper 11 decreases.

Therefore, a liquid level sensor (not shown), such as a float type, may be provided in the cleaning liquid tank 40, and the cleaning liquid may be discharged and supplied when the liquid level falls below a preset threshold value.

In addition, instead of a liquid level sensor, a viscometer 45 may be provided in the cleaning liquid tank 40 as shown in FIG. 10, and the cleaning liquid may be discharged and supplied when the viscosity measured by the viscometer 45 reaches or exceeds a preset threshold value. Note that the viscometer may be, for example, an ultrasonic viscometer, but is not limited to this.

The wiping device 1 of the above embodiment can also be used in an inkjet printing device that performs full-color printing. In this case, the inkjet printing device includes an inkjet head 2 for each color, for example, C (cyan), M (magenta), Y (yellow), and K (black), a wiping device 1 provided for each inkjet head 2 of each color, and a transport mechanism for transporting the print medium. When the inkjet head 2 is not performing a printing process, the wiping device 1 is placed close to the inkjet head 2 and performs the above-mentioned series of operations, after which each wiping device 1 moves away from each inkjet head 2, making it possible to perform a printing process again.

The wiping device of the present invention further includes the following supplementary notes.
(Additional Note)

In the wiping device of the present invention, the angle between the path of movement of the wiper by the movement mechanism and the contact surface of the wiping member with the wiper can be set so that the contact area between the wiper and the wiping member gradually increases as the wiper is moved by the movement mechanism.

In the wiping device of the present invention, the angle between the path of movement of the wiper caused by the movement mechanism and the contact surface of the wiping member with the wiper can be set to an angle that allows the wiping member to wipe off all of the contact areas between the wiper and the inkjet head.

The wiping device of the present invention can be provided with a cleaning liquid tank in which cleaning liquid is stored, and a portion of the wiping member can be immersed in the cleaning liquid in the cleaning liquid tank, while the remaining portion, including the contact surface of the wiper, can be exposed above the liquid surface of the cleaning liquid.

In the wiping device of the present invention, the movement mechanism can move the wiper in the following order: wiping of the ink ejection surface with the wiper, wiping of the wiper with a wiping member, and immersion of the wiper in cleaning liquid.

1 Wiping device 2 Inkjet head 2a Ink supply tube 10 Wiping section 11 Wiper 11a Wiper body 11b Wiper mounting member 12 Timing belt 13 First belt conveyor roller 14 Second belt conveyor roller 15 Third belt conveyor roller 16 Fourth belt conveyor roller 17 Drive motor 30 Wiping member 32 Nozzle guard 36 Nozzle plate 36a Ink ejection surface 37 Ink ejection port 40 Cleaning liquid tank 41 Recess 41a First bottom 41b Second bottom 41c Step surface 42 Supply hole 43 Discharge hole 44 Bottom plate 45 Viscometer 46 Opening 47 Side wall 50 Supply section 60 Discharge section 100 Wiping member 101 Wiper Ink Ink L Cleaning liquid

Claims (4)

a wiper for wiping an ink ejection surface on which ink ejection openings of a plurality of nozzles are arranged in an inkjet head having a plurality of nozzles for ejecting ink;
a wiping member that wipes off any deposits adhering to the wiper by contacting the wiper;
a moving mechanism for moving the wiper so as to come into contact with the wiping member;
a cleaning liquid tank in which the wiping member is installed and in which a cleaning liquid is stored ,
The contact area between the wiper and the wiping member is gradually increased as the wiper is moved by the moving mechanism ,
and a wiping device in which a portion of the wiping member is immersed in the cleaning liquid in the cleaning liquid tank, and the remaining portion of the wiping member, including the contact surface of the wiper, is exposed above the liquid surface of the cleaning liquid . The wiping device according to claim 1, wherein the angle between the path of movement of the wiper by the movement mechanism and the contact surface of the wiping member with the wiper is set so that the contact area between the wiper and the wiping member gradually increases as the wiper is moved by the movement mechanism. The wiping device according to claim 2, wherein the angle between the path of movement of the wiper by the movement mechanism and the contact surface of the wiping member with the wiper is set to an angle that allows the wiping member to wipe off all of the contact areas between the wiper and the inkjet head. 2. The wiping device according to claim 1 , wherein the movement mechanism moves the wiper in the following order: wiping of the ink ejection surface by the wiper, wiping of the wiper by the wiping member, and immersion of the wiper in the cleaning liquid.