Ink jet recording device

Abstract

To provide an ink jet recording device which can suppress ink adhesion to a side face of a recording head when performing suction purge in a state that a cap is mounted on the recording head arranged to be inclined.SOLUTION: An ink jet recording device includes: a recording head in which a nozzle surface is arranged to be inclined; a conveyance unit; a cap; a suction section; and a control section. The cap has a bottom surface section facing the nozzle surface and side wall sections erected along four sides of the bottom surface section. The suction section performs suction purge processing for sucking a sealed space between the cap and the nozzle surface. The control section executes a first separation operation for separating other side wall sections from the nozzle surface in a state that the side wall section positioned on a lower side is brought into contact with the nozzle surface, a wiping operation for moving the cap upward along the nozzle surface while bringing the side wall section positioned on the lower side into contact with the nozzle surface, and a second separation operation for separating all the side wall sections of the cap from the nozzle surface in order, when removing the cap from the nozzle surface.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an inkjet recording apparatus. [Background technology]

[0002] Conventionally, in inkjet recording devices such as inkjet printers, when printing operations are not performed for a long period of time, the ink in the nozzles of the recording head dries up, which causes the ink to not be ejected. Therefore, a capping operation is performed in which a flat box-shaped member called a cap is attached to the nozzle face to seal the area around the nozzle and keep the humidity in the sealed space high, thereby preventing the ink from drying up.

[0003] However, repeated printing operations can cause foreign matter to adhere to the nozzles, resulting in poor ink ejection. In such cases, a technique known as suction purging is available, in which the nozzle surface is capped and a suction device connected to the inside of the cap is used to suck the enclosed space between the cap and the nozzle surface, forcibly expelling the ink along with the foreign matter from the nozzles.

[0004] On the other hand, in the case of an inkjet recording device that is particularly required to be compact and space-saving, the recording head may be arranged at an angle to the horizontal plane and ink may be ejected at an angle closer to the horizontal than the vertical direction, depending on the layout relationship with the recording medium being transported. When performing suction purging on a recording head that is mounted in such an inclined state, ink that has been discharged into the cap and has not been sucked up by the suction means may accumulate at the lower end of the cap.

[0005] As a result, when the cap is removed during printing, ink remains where the cap and nozzle face were in contact, and drips down due to gravity and adheres to the side of the recording head. If the ink that adheres to the side of the recording head accumulates, the ink drips down and contaminates the paper transport path. Also, if the ink dries and hardens on the side of the recording head, depending on the shape of the cap, it may not be possible to seal the nozzle face, and the recording head will need to be cleaned or replaced.

[0006] Therefore, as a countermeasure against ink contamination on the side of the recording head, for example, Patent Document 1 discloses a configuration in which a cleaning member for cleaning the underside of the recording head is provided at the lower end of the cap in a horizontal ejection type image forming apparatus equipped with a recording head that ejects ink droplets onto paper with the nozzle surface of the recording head being approximately parallel to a vertical plane, and the underside of the recording head is cleaned by rubbing the cleaning member against it during a decap operation of the cap. Patent Document 2 discloses a configuration in which a suction cap is held movably relative to a cap holder, and the cap holder is provided with a head guide portion that contacts the upper end surface of the recording head during capping, but no guide portion is provided that contacts the lower end surface of the recording head. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2012-35501 A [Patent Document 2] JP 2013-144411 A Summary of the Invention [Problem to be solved by the invention]

[0008] The configuration of Patent Document 1 requires the addition of a cleaning member for cleaning the bottom surface (side surface) of the recording head. This results in a problem that the cap configuration becomes large, which hinders the miniaturization and space-saving of the device. Patent Document 2 takes the measure of not using the side surface of the recording head on which ink is attached for positioning the cap. However, this measure does not prevent ink from adhering to the side surface of the recording head itself, and therefore there is a problem that the attached ink drips down and contaminates the inside of the device.

[0009] In view of the above problems, the present invention aims to provide an inkjet recording device that can suppress ink adhesion to the sides of a recording head when performing suction purging with a cap attached to a recording head that is positioned at an angle. [Means for solving the problem]

[0010] In order to achieve the above object, a first configuration of the present invention is an inkjet recording device including a recording head, a cap, a suction unit, and a control unit. The recording head has a nozzle surface on which a plurality of nozzles for ejecting ink are formed. The cap is detachable from the nozzle surface of the recording head. The suction unit performs a suction purge process in which ink is sucked out from within the nozzles by suctioning an enclosed space between the cap attached to the nozzle surface and the nozzle surface. The control unit controls the attachment and detachment operation of the cap with respect to the nozzle surface. The recording head is disposed such that the nozzle surface is inclined with respect to the horizontal plane. The cap has a rectangular bottom surface portion that faces the nozzle surface at a predetermined interval, and sidewall portions that are erected along the four sides of the bottom surface portion and have tips that come into contact with the nozzle surface. When removing the cap from the nozzle face, the control unit sequentially executes a first separating operation in which a side wall portion located on the lower side of the cap is brought into contact with the nozzle face while separating the other side wall portions of the cap from the nozzle face, a wiping operation in which the cap is moved upwardly a predetermined amount along the nozzle face while bringing the side wall portion located on the lower side of the cap into contact with the nozzle face, and a second separating operation in which all side wall portions of the cap are separated from the nozzle face. Effect of the Invention

[0011] According to the first aspect of the present invention, when a suction purge process is performed on a recording head that is positioned at an angle, the ink adhering to the periphery of the contact area between the nozzle face and the side wall of the cap can be moved to near the center of the nozzle face, while the ink can be efficiently collected into the cap. This makes it possible to effectively prevent the ink from adhering to the side of the recording head and contaminating the inside of the printer. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a side cross-sectional view showing a schematic configuration of a printer 100 as an inkjet recording apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a side cross-sectional view showing a state in which a cap 20 is attached to a recording head 9 in the printer 100 of FIG. [Diagram 3] 3 is a side cross-sectional view showing the printer 100 in FIG. 2 with the cap 20 removed from the recording head 9. [Figure 4] 1 is a side cross-sectional view of a cap 20 used in a printer 100 according to a first embodiment of the invention; [Diagram 5] FIG. 1 is a side cross-sectional view showing a state in which a cap 20 is attached to a recording head 9 of a printer 100 according to a first embodiment. [Figure 6] FIG. 6 is a side cross-sectional view showing a state in which the side wall portion 21b located on the lower side of the cap 20 is separated from the nozzle surface 9a while maintaining contact between the side wall portion 21b and the nozzle surface 9a from the state shown in FIG. [Figure 7] FIG. 7 is a side cross-sectional view showing a state in which the cap 20 has been moved upward along the nozzle surface 9a while maintaining contact between the side wall portion 21b located below the cap 20 and the nozzle surface 9a from the state shown in FIG. [Figure 8] FIG. 8 is a side cross-sectional view showing a state in which the cap 20 is completely separated from the nozzle surface 9a from the state shown in FIG. [Figure 9] 11 is a side cross-sectional view of a cap 20 used in a printer 100 according to a second embodiment of the present invention. [Figure 10]FIG. 11 is a side cross-sectional view showing a state in which the cap 20 is attached to the recording head 9 of the printer 100 of the second embodiment, and the side wall portion 21b located under the cap 20 is separated from the nozzle surface 9a while maintaining contact between the side wall portion 21b and the nozzle surface 9a. [Figure 11] 11 is a side cross-sectional view of a cap 20 used in a printer 100 according to a third embodiment of the present invention. [Figure 12] FIG. 11 is a side cross-sectional view showing a state in which the cap 20 is attached to the recording head 9 of the printer 100 of the third embodiment, and the side wall portion 21b located under the cap 20 is separated from the nozzle surface 9a while maintaining contact between the side wall portion 21b and the nozzle surface 9a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1. Configuration of the Inkjet Recording Apparatus Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is an explanatory diagram showing a schematic configuration of a printer 100 as an inkjet recording device according to one embodiment of the present invention. The printer 100 is equipped with a paper feed cassette 2 which is a paper storage section. The paper feed cassette 2 is disposed below the printer main body 1. Inside the paper feed cassette 2, paper P, which is an example of a recording medium, is stored.

[0014] A paper feed unit 3 is disposed downstream of the paper feed cassette 2 in the paper transport direction (hereinafter simply referred to as the transport direction) (upper right of the paper feed cassette 2 in FIG. 1). The paper feed unit 3 is composed of a pair of paper feed rollers, for example, a feed roller and a retard roller. The paper sheets P stored in the paper feed cassette 2 are separated and sent out one by one by the paper feed unit 3 toward the downstream side in the transport direction.

[0015] A first paper transport path 4a is provided inside the printer 100. The first paper transport path 4a is located on the upper right and downstream side in the transport direction relative to the paper feed cassette 2. The paper P sent out from the paper feed cassette 2 is transported approximately vertically upward along the side of the printer body 1 by the first paper transport path 4a.

[0016] At the downstream end of the first paper transport path 4a in the transport direction, a transport unit 5 and a recording head 9 are disposed. The paper P sent out from the paper feed cassette 2 passes through the first paper transport path 4a and reaches the transport unit 5.

[0017] The recording head 9 is disposed at a predetermined angle with respect to the horizontal plane. The transport unit 5 is disposed facing the nozzle surface 9a (see FIG. 5) of the recording head 9 at a predetermined distance, and transports the paper P along the nozzle surface 9a. The nozzle surface 9a is formed with a large number of nozzles (not shown) for discharging ink. The recording head 9 records (prints) an image on the paper P by discharging ink onto the paper P according to image data received from an external computer in response to a control signal from a control unit 90. Although one recording head 9 is shown in FIG. 1, one or more recording heads 9 are provided for each of the colors yellow, magenta, cyan, and black.

[0018] The ink containers 11Y to 11K store ink of each color, yellow (Y), magenta (M), cyan (C), and black (K), respectively. The ink supply system 6 is composed of an ink supply passage, a pump, an on-off valve, a check valve (none of which are shown), etc. The ink supply system 6 supplies the four colors (yellow, cyan, magenta, and black) of ink stored in the ink containers 11Y to 11K to the recording head 9 for each color in response to a control signal from the control unit 90.

[0019] In the paper transport direction (the direction of arrow A), a second paper transport path 4b is provided downstream (upper in FIG. 1) of the transport unit 5. The paper P on which an image is recorded by the recording head 9 passes through the second paper transport path 4b and is discharged to a discharge tray 15 provided on the top surface of the printer 100 via a discharge section 12 consisting of a pair of discharge rollers.

[0020] A cap 20 is disposed below the recording head 9. Although one cap 20 is shown in Fig. 1, the same number of caps 20 as the recording heads 9 are provided, which are disposed corresponding to the four colors of ink.

[0021] In the printer 100, in order to remove dried or thickened ink and foreign matter inside the nozzles of the recording head 9, when printing starts after a long period of inactivity and between printing operations, with the cap 20 attached to the nozzle face 9a, a suction purge process is performed in which the suction pump 7 suctions the space (sealed space) between the nozzle face 9a and the cap 20 to forcibly suck out ink from all the nozzles of the recording head 9, in preparation for the next printing operation. The ink sucked into the cap 20 from the nozzles (purged ink) is discharged to the outside of the cap 20 by the suction pump 7, and then collected in the waste ink tank 8 via a waste ink collection flow path (not shown).

[0022] Fig. 2 is a side cross-sectional view showing a state in which the cap 20 is attached to the recording head 9 in the printer 100 of Fig. 1. When printing operations are not performed for a long period of time, the control unit 90 moves the recording head 9 in a direction perpendicular to the transport direction (the direction of the arrow B) by a driving source such as a motor (not shown) to separate it from the transport unit 5. Next, the control unit 90 moves the cap 20 upward from the retreat position (the position in Fig. 1) to position it between the recording head 9 and the transport unit 5. Furthermore, the control unit 90 moves the cap 20 in a direction approaching the recording head 9 (the direction of the arrow B) to attach it to the nozzle surface 9a of the recording head 9.

[0023] Fig. 3 is a side cross-sectional view showing a state in which the cap 20 has been removed from the recording head 9 in the printer 100 of Fig. 2. When performing a printing operation from the state of Fig. 2, the control unit 90 moves the cap 20 in a direction away from the recording head 9 (opposite direction of arrow B) and removes it from the nozzle surface 9a of the recording head 9. Thereafter, the control unit 90 moves the cap 20 back to the waiting position, and moves the recording head 9 in a direction approaching the transport unit 5 (opposite direction of arrow B) to return to the state of Fig. 1.

[0024] [2. Cap structure] Next, the configuration of the cap 20 will be described. Fig. 4 is a side cross-sectional view of the cap 20 used in the printer 100 according to the first embodiment of the invention. The cap 20 has a main body 21 and an ink absorber 22. The main body 21 is a flat rectangular parallelepiped with an open top, having a rectangular bottom surface 21a that faces the nozzle surface 9a (see Fig. 5) at a predetermined distance, and side wall portions 21b that stand along the four sides of the bottom surface 21a. The main body 21 is integrally formed from an elastic material such as rubber.

[0025] The ink absorber 22 is disposed along the bottom surface portion 21a inside the main body portion 21. The ink absorber 22 is formed of a porous material such as a sponge. Although not shown here, the cap 20 is provided with a suction port to which the suction pump 7 is connected, and an air release valve (neither shown) that connects the inside and outside of the cap 20 or blocks them to switch the inside of the cap 20 between a sealed state and an air-open state.

[0026] Fig. 5 is a side cross-sectional view showing the state in which the cap 20 is attached to the recording head 9 of the printer 100 of the first embodiment. As shown in Fig. 5, when the cap 20 is attached to the recording head 9, the tips of the side wall portions 21b formed on the four sides of the main body portion 21 are in close contact with the nozzle surface 9a. This forms an enclosed space between the nozzle surface 9a and the cap 20, suppressing thickening of the ink in the nozzles formed in the nozzle surface 9a.

[0027] In addition, since the recording head 9 is inclined, the cap 20 is also inclined when attached along the inclined nozzle surface 9a. Therefore, the ink In that is not completely absorbed by the ink absorber 22 accumulates on the lower end side of the cap 20.

[0028] 3. Removing the cap from the recording head Next, a detailed description will be given of the operation of removing the cap 20 from the recording head 9. Fig. 6 is a side cross-sectional view showing a state in which the side wall portion 21b located below the cap 20 is separated from the nozzle surface 9a while maintaining contact between the side wall portion 21b and the nozzle surface 9a from the state shown in Fig. 5.

[0029] First, as shown in FIG. 6, in a state where the side wall portion 21b located on the lower side of the cap 20 (lower left side of FIG. 6) is in contact (nipped) with the nozzle surface 9a, the other side wall portion 21b of the cap 20 is separated from the nozzle surface 9a (first separating operation). At this time, even if the ink In (see FIG. 5) that has not been absorbed by the ink absorber 22 accumulates on the lower end side of the cap 20, the ink In can easily flow toward the ink absorber 22 by changing (making the inclination of) the cap 20. As a result, the ink In accumulated on the lower end side of the cap 20 can be absorbed by the ink absorber 22. Note that a small amount of ink In remains in the nip portion between the side wall portion 21b located on the lower side of the cap 20 and the nozzle surface 9a.

[0030] Fig. 7 is a side cross-sectional view showing a state in which the cap 20 is moved upward along the nozzle surface 9a while maintaining contact between the side wall portion 21b located on the lower side of the cap 20 and the nozzle surface 9a from the state shown in Fig. 6. After the first separation operation is performed, the cap 20 is moved upward a predetermined distance (for example, about 1 cm) along the nozzle surface 9a while the side wall portion 21b located on the lower side of the cap 20 is brought into contact (nipped) with the nozzle surface 9a (wiping operation) as shown in Fig. 7. By performing this operation, the ink adhering to the portion of the nozzle surface 9a where the side wall portion 21b contacts is wiped off by the side wall portion 21b, and flows down along the side wall portion 21b to the inside of the cap 20 together with the ink In remaining in the nip portion.

[0031] Fig. 8 is a side cross-sectional view showing a state in which the cap 20 has been completely separated from the nozzle surface 9a from the state in Fig. 7. After the wiping operation is performed, all of the side wall portions 21b of the cap 20 are separated from the nozzle surface 9a (second separating operation) as shown in Fig. 8. Here, since a water-repellent film (not shown) made of fluororesin or the like is formed on the nozzle surface 9a, ink is more likely to adhere to the rubber cap 20 than to the nozzle surface 9a.

[0032] Therefore, even if some ink In remains in the nip portion between the side wall portion 21b located under the cap 20 and the nozzle surface 9a, most of the ink adheres to the cap 20 side, and only a small amount of ink remains on the nozzle surface 9a. Such a small amount of ink does not drip down along the slope of the nozzle surface 9a, and there is no risk of contaminating the side surface of the recording head 9.

[0033] By removing the cap 20 from the nozzle surface 9a of the recording head 9 according to the above procedure, when a suction purge process is performed on the recording head 9 that is positioned at an angle, the ink In adhering to the periphery of the contact portion of the nozzle surface 9a with the side wall portion 21b of the cap 20 can be moved to near the center of the nozzle surface 9a, while efficiently collecting the ink In into the cap 20. This makes it possible to effectively prevent the ink from getting around and adhering to the side surface of the recording head 9, thereby contaminating the inside of the printer 100.

[0034] [4. Other configurations of the cap] 9 is a side cross-sectional view of a cap 20 used in a printer 100 according to a second embodiment of the invention. In this embodiment, an inclined surface 23 is formed by chamfering (cutting) the outer corner downward at the tip of a side wall portion 21b (the side wall portion 21b on the left side in FIG. 9) that is located at the lower end of the cap 20 when attached to the recording head 9.

[0035] 10 is a side cross-sectional view showing a state in which, from a state in which the cap 20 is attached to the recording head 9 of the printer 100 of the second embodiment, the side wall portion 21b located on the lower side of the cap 20 is separated from the nozzle surface 9a while maintaining contact between the other side wall portion 21b and the nozzle surface 9a. The angle θ1 (see FIG. 9) of the inclined surface 23 with respect to the horizontal plane is set to be the same as the rotation angle θ2 of the cap 20 when performing the first separating operation from the attached state of the cap 20 (the state of FIG. 5). For example, when the cap 20 is rotated by 20° from the attached state to perform the first separating operation, the angle θ1 of the inclined surface 23 is set to 20°.

[0036] 10, it is possible to reliably bring the nozzle surface 9a and the inclined surface 23 into surface contact with each other after the first separating operation is performed. Therefore, the ink In remaining in the nip portion between the nozzle surface 9a and the side wall portion 21b located below the cap 20 is less likely to slip through the nip portion, and dripping of the ink onto the side surface of the recording head 9 can be more effectively suppressed.

[0037] 11 is a side cross-sectional view of a cap 20 used in a printer 100 according to a third embodiment of the invention. In this embodiment, a curved surface 24 is formed at the tip of a side wall 21b (the side wall 21b on the left side in FIG. 11) that is located at the bottom end of the cap 20 when attached to the recording head 9, with the inner corner having an arc shape (R surface) in cross section.

[0038] 12 is a side cross-sectional view showing a state in which, from a state in which the cap 20 is attached to the recording head 9 of the printer 100 of the third embodiment, the side wall portion 21b located on the lower side of the cap 20 is separated from the nozzle surface 9a while maintaining contact between the side wall portion 21b and the nozzle surface 9a. According to the configuration of this embodiment, when performing a wiping operation, the ink In remaining in the nip portion between the side wall portion 21b located on the lower side of the cap 20 and the nozzle surface 9a tends to flow downward along the curved surface portion 24. As a result, the ink In is easily collected in the ink absorber 22, and contamination of the side surface of the recording head 9 caused by the ink In slipping through the nip portion can be suppressed.

[0039] [5. Other] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, the inclination angle of the nozzle surface 9a of the recording head 9 can be set appropriately according to the layout and configuration inside the printer 100. In addition, the rotation angle of the cap 20 when performing the first separating operation of the cap 20 and the movement amount of the cap 20 when performing the wiping operation of the cap 20 can also be set appropriately within a range that can suppress the adhesion of ink to the side surface of the recording head 9.

[0040] In addition, in the above embodiment, a color printer that records color images using four colors of ink has been described as an inkjet recording device, but the present invention can also be applied to a monochrome printer that records monochrome images using black ink. [Industrial Applicability]

[0041] The present invention can be used in inkjet recording devices such as inkjet printers. [Explanation of symbols]

[0042] 1 Printer body 2 Paper Cassette 3 Paper feed section 4a First paper transport path 4b Second paper transport path 5. Transport unit 6 Ink supply system 7 Suction pump (suction part) 8 Waste ink tank 9. Recording Head 9a Nozzle surface 11Y~11K Ink Container 20 Cap 21 Main body 21a Bottom part 21b Side wall part 22 Ink absorber 23 Slope 24 Curved part 90 Control section 100 Printers (inkjet recording devices) P Paper (recording medium)

Claims

1. a recording head having a nozzle surface on which a plurality of nozzles for ejecting ink are formed; a cap that is detachable from the nozzle surface of the recording head; a suction unit that performs a suction purge process to suck out the ink inside the nozzles by sucking an enclosed space between the nozzle surface and the cap attached to the nozzle surface; a control unit that controls an attachment / detachment operation of the cap with respect to the nozzle surface; In an inkjet recording apparatus comprising: the recording head is disposed such that the nozzle surface is inclined with respect to a horizontal plane, The cap is a rectangular bottom surface portion facing the nozzle surface at a predetermined interval; a side wall portion that is provided along each of the four sides of the bottom surface portion and has a tip portion that contacts the nozzle surface; having When removing the cap from the nozzle surface, the control unit a first separating operation of separating the other side wall portion of the cap from the nozzle surface while keeping the other side wall portion located under the cap in contact with the nozzle surface; a wiping operation in which the cap is moved upward along the nozzle face by a predetermined distance while the side wall portion located under the cap is brought into contact with the nozzle face; a second separating operation of separating all of the side wall portions of the cap from the nozzle surface; The ink jet recording apparatus is characterized in that the above steps are carried out in sequence.

2. 2. The inkjet recording apparatus according to claim 1, wherein an outer corner of the side wall portion located below the cap when attached to the recording head is chamfered downward to form an inclined surface.

3. 3. The ink jet recording apparatus according to claim 2, wherein an angle of the inclined surface with respect to a horizontal plane is the same as a rotation angle of the cap in the first separating operation.

4. 2. The inkjet recording apparatus according to claim 1, wherein a tip of the side wall portion that is located under the cap when attached to the recording head is formed with a curved portion having an inner corner that is arc-shaped in cross section.

5. 5. The ink jet recording apparatus according to claim 1, further comprising an ink absorber made of a porous material disposed inside the cap along the bottom surface of the cap.

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