JPH09254401A - Ink jet recording device - Google Patents

Abstract

The present invention provides an inkjet recording apparatus that includes an elastic cap that covers the ejection surface of a print head and that can reduce the internal pressure rise during capping with a simple mechanism. SOLUTION: A cap 51 is provided so as to be movable back and forth and biased in a protruding direction with respect to a cap holder 52 directed to an ejection surface 4 of the print head 3 in association with the movement of a carriage 7 on which the print head 3 is mounted, When the cap 51 is pressed against the discharge surface 4 and the cap 51 moves out toward the cap holder 52, the valve member 67 that closes the outside air communication port 62 that communicates with the internal space 61 of the cap 51 is attached to the cap holder 52.
It has a structure to be installed in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus provided with a cap that is pressed against a print head so that when the print head is not used, the ejection surface can be covered with the cap to shut off the air from the outside. .

[0002]

2. Description of the Related Art An ink jet recording apparatus is adapted to eject and eject ink droplets from ejection ports of a print head so that the ink droplets adhere to printing paper such as paper for recording. In such an ink jet recording apparatus, when the print head is not used for a long time, the viscosity of the ink increases due to the evaporation of water from the ejection port and the ejection speed of the ink becomes slow or clogging occurs. It may happen.

In order to reduce such defective ejection of ink due to non-use, when the print head is not used, capping means for covering the ejection surface of the print head with an elastic cap to shut off the outside air is used. Sometimes.

A conventional example of this capping means will be described with reference to FIG. 6A and 6B are cross-sectional views of the main part of the capping means. FIG. 6A shows a state before capping and FIG. 6B shows a state after capping. The cap 101 has a deep dish shape having an internal space 102, and is formed of an elastic body such as rubber. A plate 103 is used to fix the periphery and the back surface of the cap 101, and the plate 103 is held in a cap holder 104 having a rectangular tubular shape so as to be able to move back and forth. Further, between the plate 103 and the cap holder 104, a pressing spring 105 that biases the cap 101 in the protruding direction is provided. The cap holder 104 is slidable in the thickness direction of the drawing along the diagonal shaft 106, and normally the tension spring 10
7 in the position shown.

A carriage 1 having a print head 110 mounted thereon.
When 11 moves toward the front in the thickness direction of the paper surface, the contact piece 108 projecting from the cap holder 104 moves the carriage 111.
At this time, the cap holder 104 moves forward with the carriage 111 in the thickness direction of the paper surface. Then, the cap holder 104 moves the print head 110 along the diagonal shaft 106.
To the ejection surface 112 (direction of arrow a). The cap 101 hits the ejection surface 112 and pushes the spring 105.
The pressure is applied by the urging force of (1), and the state shown in FIG.
Since the ejection surface 112 is exposed only to the internal space 102 which is covered with the cap 101 and is hermetically sealed, water evaporation from the ejection port 112 is prevented.

[0006]

However, the cap 1
01 is a plate-shaped elastic body such as rubber, and therefore the cap 101 is attached to the ejection surface 112 of the print head 110.
When pressed against, the lip portion around the cap 101 is crushed and the volume of the internal space 102 is reduced, so the internal space 102 may be in a pressurized state. Internal space 10
When 2 is in a pressurized state, there is a risk that air, dust, and the like will enter the ink ejection openings.

Therefore, it is conceivable to apply the outside air release valve used for the cap of the purging device for sucking the ink from the ejection port of the print head 110 to eliminate the clogging to the capping means for covering the ejection surface when not in use. The outside air release valve in this purging device is provided with an outside air communication port in the cap and a valve member for opening and closing this outside air communication port. However, the movement of the cap with respect to the discharge surface and the opening and closing of the outside air release valve are performed by separate mechanisms. For example, JP-A-3-87267 and JP-A-3-8726.
There is a problem in that the structure becomes complicated by providing two rails for driving the cover cover of the cap and the rail for driving the opening / closing of the outside air release valve as in JP-A-8.

Therefore, the present invention is to provide an ink jet recording apparatus which is provided with an elastic cap which covers the ejection surface of the print head and which can reduce the internal pressure rise at the time of pressure contact of the cap with a simple mechanism. It is an object.

[0009]

In order to solve the above-mentioned problems, the invention of claim 1 is an ink jet recording apparatus provided with an elastic cap for covering the ejection surface of a print head, wherein the cap is used for printing. The cap is provided so as to be movable back and forth and urged in a protruding direction with respect to a cap holder that faces the ejection surface of the print head in association with the movement of a carriage on which the head is mounted. The cap holder is provided with a valve member that closes an outside air communication port communicating with the internal space of the cap when the cap holder is withdrawn toward the cap holder. In the latter half of the process of leaving the cap, the outside air communication port is closed by the valve member.

A second aspect of the present invention is the ink jet recording apparatus according to the first aspect, wherein the internal space of the cap, the outside air communication port of the cap, and the valve member face the print head. Are arranged in a line. A single row makes it easy to arrange the valve members.

A third aspect of the present invention is the ink jet recording apparatus according to the second aspect, wherein the valve member is provided so as to be movable back and forth with respect to the cap holder and biased in a protruding direction, and the valve member is provided with the valve member. The biasing force is weaker than the biasing force of the cap holder. The degree to which the cap is pressed by the biasing force of the valve member is reduced.

According to a fourth aspect of the present invention, there is provided the ink jet recording apparatus according to the first aspect, wherein the cap covers the ejection surface and blocks the outside air when the print head is not used. The capping means when the print head is not used is located further outside the purging device and can be operated in one motion separated from the purging device.

A fifth aspect of the present invention is the ink jet recording apparatus according to the fourth aspect, wherein the print heads are provided in a plurality of rows, and the heads are provided in a plurality of rows corresponding to the print heads. . For example, a color ink jet recording device has four print heads.

[0014]

DETAILED DESCRIPTION OF THE INVENTION An ink jet recording apparatus of the present invention will be described below with reference to FIGS. First, the overall configuration of the inkjet recording apparatus 1 will be described with reference to FIG.

In FIG. 5, the ink jet recording apparatus 1
The main body frame 2 includes a print head 3 having a plurality of nozzles, a recovery mechanism RM, a paper feed mechanism LM, and the like. A cylindrical platen roller 5 is arranged in the center of the main body frame 2. The platen roller 5 conveys the print paper P supplied from the paper feed cassette or the manual paper feed unit while facing the print head 3, and forms a part of the paper feed mechanism LM. The platen roller 5 is brought into close contact with the printing paper P by a pressure roller (not shown) provided on the upper side. Further, the platen roller 5 is rotationally driven by an LF motor (not shown) to sub-scan the printing paper P.

A carriage 7 is provided in front of the platen roller 5. The carriage 7 is equipped with the ink jet type print head 3, and the print head 3
A plurality of ink containers 8A to 8D containing inks (black B, yellow Y, cyan C, and magenta M inks) to be supplied to the respective units are detachably mounted,
It is movable along a carriage shaft 9 provided in parallel with the platen roller 5. As a result, the print head 3
Are main-scanned along the platen roller 5. The print head 3 includes four print heads 3A to 3D that eject black B, yellow Y, cyan C, and magenta M inks.
Are arranged in a row in the main scanning direction.

A carriage 7 is provided below the body frame 2.
A CR motor 10 for driving the motor is arranged. The CR motor 10 drives the carriage 7 via the belt 11, and uses a step motor or a DC motor. A recovery mechanism RM for the print head 3 is arranged on the right side of the platen roller 5.

The recovery mechanism RM is a capping means 13 for blocking the outside air when the print head 3 is not used.
The ink in the print head 3 is sucked in order to prevent the ejection failure of the ink due to the generation of air bubbles inside the device, the deposition of ink droplets on the ejection surface, or the like during use. It comprises a purging device 18 and a wiping device 15 for wiping the nozzle surface of the print head 3. The capping means 13 is arranged further outside the purging device 18.

The capping means 13 has four caps 51A to 51D corresponding to the four print heads 3A to 3D.
Each of the caps 51 </ b> A to 51 </ b> D is held in a common cap holder 52 so as to be able to move back and forth. A supporting portion 53 is provided so as to project from a lower portion of the cap holder 52, and the supporting portion 53 is supported so as to be movable along an oblique shaft 54. The oblique shaft 54 is inclined so as to approach the carriage shaft 9, and the cap holder 52 is normally located at the position shown by the extension spring 57. This support 53
An engaging protrusion 55 is attached to the tip of the engaging protrusion 55. When the engaging protrusion 55 engages with the engaging portion 56 of the carriage 7, the engaging protrusion 55 moves together with the carriage 9. Then, the entire cap holder 52 moves toward the print head 3 by the oblique shaft 54, and the caps 51A to 51D move to the print heads 3A to 3D.
The discharge surface of 3D is pressed to cover the discharge surface from the outside air.

A cap 17 is also provided at the tip of the purging device 18. The purging device 18 is a known pump 1 when the print head 3 is covered by the cap 17.
4 is used to generate a negative pressure to suck and recover defective ink inside the nozzle to any of the print heads 3A to 3D. Purging mechanism 32 together with purging device 18
The pump 14 constituting the above is driven by a paper feed LF motor (not shown) via a cam gear 19.

The cap 17 and the wiping device 15 of the purging device 18 are slidably held in the housing 71. The cap 17 and the wiper are cam gears 1.
The structure is such that it advances and retreats toward the print head 3 with the rotation of 9.

In the present embodiment, especially the capping means 1
3, the outside air communication port and the valve member are adopted to prevent the pressure rise in the cap, and the detailed structure thereof will be described with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 3 is a print head, 7 is a carriage, 9 is a carriage shaft, 53 is a support portion, 54 is an oblique shaft, 55 is an engaging protrusion, 56 is an engaging portion, and 57 is a tension spring. Yes, it is the same as that described in FIG.

The cap 51 is composed of a dish-shaped cross section 51a and a back projection 51b, and an internal space 61 having a trapezoidal cross section is formed in the dish-shaped cross section 51a. Further, an outside air communication port 62 is provided which penetrates the center of the rear surface protruding portion 51b and communicates the outside air with the internal space 61. The cap 51 is fitted in the recess of the plate 63. The outer circumference and the back surface of the cap 51 are held in close contact with the concave portion of the plate 63. The back projection 51b of the cap 51 mentioned above projects from the hole on the back of the plate 63, and forms a contact surface 51c for a valve member described later. This cap 51
Is formed of an elastic body such as rubber, and has a lip portion 51 which is elastic and can be pressed against the ejection surface 4 of the print head.
d, and an abutment surface 5 that comes into contact with a valve member to be described later with elasticity.
1c.

As shown in FIG. 2, the cap holder 5
Reference numeral 2 is for holding the cap 51 in a retractable manner via the plate 63. This cap 5
1 is configured integrally with a storage portion 64 for each of the four caps 51A to 51D corresponding to the four print heads 4A to 4D. A key groove 64a with which a key portion 63a protruding from the plate 63 is engaged is formed on the side surface of the storage portion 64.
Is formed, and the cap 51 is movable back and forth along the central axis of the storage portion 64. A first pressing spring 66 is provided between the back surface portion 65 of the storage portion 64 and the plate 63, and the cap 51 is given a biasing force determined by the initial pressing amount of the first pressing spring 66. The most protruding position of the cap 51 is determined by the end of the key groove 64a.

As shown in FIG. 1, a cylindrical guide 66 is provided at the center of the back face portion 65 of the cap holder toward the accommodating portion 64, and a valve member 67 is slidably held by the cylindrical guide 66. ing. The head portion 67a of the valve member 67 faces the contact surface 51c of the cap, and when the head portion 67a and the contact surface 51c contact each other, the outside air communication port 62 is closed. The head portion 67a and the back surface portion 65 of the valve member 67
A second pushing spring 68 is provided between the two, and the valve member 67 is given a biasing force determined by the pushing amount of the second pushing spring 68. The most protruding position of the valve member 67 is determined by the stopper portion 67b.

Further, the urging force F1 of the first pushing spring 66 against the cap 51 and the second pushing spring 6 against the valve member 67.
There is a relation of F1> F2 between the urging force F2 of 8 and
It is desirable that the biasing force F2 be minimized to seal the outside air communication port 62. Further, the head portion 67a of the valve member 67 is provided with a predetermined gap (pushing margin) ε between the head portion 67a and the contact surface 51c of the cap.

Next, the operation of the capping means described above will be explained with reference to the operation diagram of FIG. 3 and the time chart diagram of FIG.

First, when the print head 3 is not used, the carriage 7 moves toward the front side of the drawing, the engaging portion 56 of the carriage 7 contacts the engaging protrusion 55 of the capping means 13, and the capping operation is started. (See FIG. 5). The state of the start of capping is shown in FIG.
4A, which corresponds to the point on the time chart of FIG. 4, at which point the cap 51 begins to close.

In FIG. 3B, when the carriage 7 further moves, the cap holder 52 moves in the direction of arrow A, and the ejection surface 4 of the print head 3 and the lip portion of the cap 51 come into contact with each other. In this state, a gap ε is formed between the contact surface 51c of the cap 51 and the head 67a of the valve member 67.
Exists. The state in which the press contact is started corresponds to the point in the time chart of FIG. 4, and the urging force of the first pressing spring 66 acts on the cap 51 all at once, and the lip portion of the cap 51 is deformed so as to be crushed slightly. Then, although the volume of the internal space 61 is slightly reduced, the external air communication hole 62 remains open, so that the internal space 61 communicates with the external air and is maintained at atmospheric pressure. The cap urging force F1 in FIG. 4 is not vertical but almost vertical because the cap 51 is elastically deformed. Further, the urging force changes substantially horizontally after standing up almost vertically because the first pressing spring 66 is pushed and its length is shortened, and the urging force F1 is slightly increased.

When the carriage 7 further moves from the state of FIG. 3B, the cap holder 52 further moves in the direction of arrow A, and the ejection surface 4 of the print head 3 and the lip portion of the cap 51 are kept in contact with each other. As it is, the gap ε becomes smaller between the contact surface 51c of the cap 51 and the head 67a of the valve member 67, and the state of FIG. 3C is reached. Cap 5
The state where the contact surface 51c of No. 1 and the head portion 67a of the valve member 67 are in contact corresponds to the point in FIG. 4, the valve member 67 is closed, and the valve biasing force F2 acts. Then, as shown in FIG. 3 (c),
The outside air communication hole 62 is closed, and the internal space 61 of the cap 51 becomes a closed space. Therefore, the ejection surface 4 of the print head 3 is covered with the closed space in the cap 51, and the ejection surface 4 is prevented from drying.

In FIG. 4, when the carriage 7 moves further and the cap 51 moves from point to point, the valve member 67 is moved.
The shutoff of the outside air communication hole 62 by means of is assured. Further, the cap urging force F is generated at the point where the valve member 67 starts to operate.
Since the valve biasing force F2 acts on the cap 1,
The urging force acting on is increased to F1 + F2. But F
Since 1> F2 is set, the elastic deformation of the cap 51 is small even when the urging force F2 is applied, and the cap 51
The cap 51 is not deformed to such an extent that the internal space 61 of FIG. That is, the valve biasing force F2 is set to such a degree that it blocks the outside air communication hole 62 and the elastic deformation of the cap 51 does not adversely affect the print head 3.

In the above-described embodiment, the cap holder 5
2 moves toward the print head 3, so that the cap 51 is pressed against the print head 3 and the outside air communication hole 62 of the cap 51 is shut off by the valve member 67 after the press contact. The structure is simplified as compared with the case where the pressure contact with the print head 3 and the blocking of the outside air communication hole 62 of the cap 51 by the valve member 67 after the pressure contact are separately performed by another guide member. In particular, like the color ink jet recording apparatus, the print heads 3A, 3 for four colors are used.
When B, 3C, and 3D are arranged in a row, providing a separate guide member for each print head complicates the structure further, so the one-motion mechanism of this embodiment is effective. . Further, since the capping means 13 is disposed further outside the purging device 18, it is difficult to dispose a complicated mechanism with respect to the capping means 13, and the present embodiment operates easily in one motion. The mechanism of is effective.

However, the one-motion mechanism of this embodiment can also be applied to a monochrome ink jet recording apparatus having one print head. Further, it is applicable not only to the capping means used when the print head is not used, but also to the cap of the purging device for suction recovery used when the ink is sucked by the ejection port of the print head.

In FIG. 2, only one cap 17 of the purging device 18 is provided so as to correspond to each of the print heads 3A, 3B, 3C and 3D. Cap 1
Reference numeral 7 is provided so as to be slidable in the housing 71 toward the print head 3, and has a projection 72 that engages with the cam groove 19a of the cam gear 19, and moves forward and backward in the housing 71 as the cam gear 19 rotates. And the cap 17
Is pressed against a specific print head, and the inside of the cap 17 is suctioned by the pump 14 (FIG. 1) operated by the cam gear 19. When the cap 17 is pressed against the print head, the elastic cap 17 is deformed and the pressure in the space inside the cap 17 increases. Therefore, it is desirable that the atmosphere communication hole of the cap 17 is opened at the beginning of the pressure contact of the cap 17 with the print head, and the atmosphere communication hole of the cap 17 is closed before the suction in the cap 17. Also in this case, the one-motion cap pressing and atmosphere communication hole blocking mechanism of the present embodiment can be adopted.

[0036]

As described above, according to the first aspect of the invention, the elastic force is applied during one motion in which the cap holder moves toward the ejection surface of the print head in association with the movement of the carriage on which the print head is mounted. It is possible to avoid an increase in pressure in the internal space due to deformation of the cap of the body due to pressure contact and to seal the internal space of the cap in order. Also, the adoption of this one-motion simplifies the structure around the cap.

According to the invention of claim 2, in addition to the effect of claim 1, by arranging the internal space, the outside air communication port and the contact member in series, the valve member can be easily arranged and the structure is further simplified. Has the effect.

According to the invention of claim 3, in addition to the effect of claim 2, the degree to which the cap is pressed by the urging force of the valve member is reduced. Therefore, even if there is a valve member, the cap is kept in an appropriate pressed state. It has the effect of drooping.

The invention of claim 4 has the effect that it can be performed with the simple structure of one motion of claim 1, and is located outside the purging device to cover the ejection surface when the print head is not in use, thereby exposing the outside air. It has an effect of being effectively exhibited when applied to the capping means for blocking.

According to a fifth aspect of the present invention, the effect of the fourth aspect can be obtained.
It is particularly effective for capping means having a complicated structure in which a plurality of caps are arranged in a row.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a capping means according to a main part of the present invention.

FIG. 2 is a cross-sectional view of the capping means according to the main part of the present invention.

FIG. 3 is an operation diagram of the capping means according to the main part of the present invention.

FIG. 4 is a time chart of the operation of the capping means according to the main part of the present invention.

FIG. 5 is a perspective view of the ink jet recording apparatus of the present invention.

FIG. 6 is a vertical sectional view of a conventional capping means.

[Explanation of symbols]

 1 Ink Jet Recording Device 3 Print Head 3A, 3B, 3C, 3D Color Print Head 4 Ejection Surface 7 Carriage 13 Capping Means 51 Cap 52 Cap Holder 61 Internal Space 62 External Air Communication Port 66 First Pushing Spring (Cap Biasing Force) 67 Valve Member 68 Second push spring (valve member biasing force)

Claims (5)

[Claims] 1. An inkjet recording apparatus comprising an elastic cap that covers an ejection surface of a print head, wherein the cap is provided on the ejection surface of the print head in conjunction with movement of a carriage on which the print head is mounted. The cap holder is provided so as to be movable back and forth and biased in a projecting direction, and when the cap is pressed against the discharge surface and the cap is withdrawn toward the cap holder, it communicates with the outside air communicating with the internal space of the cap. An ink jet recording apparatus, wherein a valve member for closing a mouth is provided on the cap holder. 2. The ink jet recording apparatus according to claim 1, wherein the internal space of the cap, the outside air communication port of the cap, and the valve member are arranged in a line toward the print head. 3. The valve member is provided so as to be movable back and forth with respect to the cap holder and biased in a projecting direction, and the biasing force of the valve member is weaker than the biasing force of the cap holder. 2. The inkjet recording device according to 2. 4. The ink jet recording apparatus according to claim 1, wherein the cap covers the ejection surface and shields it from the outside air when the print head is not used. 5. The ink jet recording apparatus according to claim 4, wherein the print heads are provided in a plurality of rows, and the heads are provided in a plurality of rows corresponding to the print heads.