JP2018199278A - Liquid discharge head and liquid discharge device - Google Patents

Abstract

To provide a liquid discharge head which inhibits rising of a liquid surface of a wiped liquid (liquid rise) during wiping, enables the liquid adhering to a nozzle and foreign objects to be easily removed, and inhibits dryness of the liquid in the nozzle after the wiping to achieve stabilization of discharge, and to provide a liquid discharge device.SOLUTION: A liquid discharge head 50 includes a nozzle array, in which multiple nozzles 51 for discharging an ink are arranged at an interval in a first direction D, on a bottom surface 62 connecting facing step parts 6. A depth H of each step part 6 is constant relative to the first direction D. A width of a center part as seen in a depth direction of the step part 6 increases relative to the first direction D.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus including the liquid discharge head.

  2. Description of the Related Art Conventionally, liquid ejecting apparatuses such as ink jet printers that eject liquid such as ink from nozzles of an ejection head are known. In such an apparatus, the liquid discharged from the nozzle may adhere to the nozzle formation surface of the discharge head. If the liquid adheres to the nozzle forming surface, the liquid is not properly discharged from the nozzle, which may cause deterioration in image quality. For this reason, usually, before and after the use of the nozzle, the ink forming surface is moved by a wiper provided in the liquid ejection device, thereby wiping off ink remaining on the nozzle and dust adhering to the nozzle.

  According to the liquid ejecting apparatus of Patent Document 1, it is disclosed that the nozzle plate includes a concave portion with a gentle edge surface. Therefore, when the wiper wipes the nozzle forming portion, the edge of the recess can be smoothly passed through the wiper. Therefore, it is difficult for the liquid to remain unwiped at the edge of the recess.

JP 2014-184557 A

  In the liquid ejecting apparatus including Patent Document 1, when the nozzle row is formed on the bottom of the concave portion of the nozzle plate or the bottom surface of the stepped portion, wiping with a wiper in the direction of the nozzle row Ink) gradually increases and the liquid level of the liquid rises, so that there is a problem that it cannot be allowed at the recesses or stepped portions, and as a result remains on the nozzle plate.

  In addition, the ink in the nozzles dries and the viscosity increases (thickens), causing problems such as flight bending and delay in ejection timing, resulting in problems such as irregular landing positions. There was a problem to do.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid discharge head according to this application example includes a nozzle row in which a plurality of nozzles that discharge liquid are arranged at intervals in a first direction on a bottom surface that connects opposing stepped portions. The depth of the portion is constant with respect to the first direction, and the width of the central portion in the depth direction of the stepped portion increases with respect to the first direction.

According to the liquid ejection head of this application example, the depth of the stepped portion is constant with respect to the first direction, and the width of the central portion in the depth direction of the stepped portion increases with respect to the first direction. To do. Thereby, the cross-sectional area surrounded by the step portion and the bottom surface increases with respect to the first direction. Therefore, when wiping is performed with the wiper in the first direction, the liquid that has been wiped off can be easily flowed in the first direction, thereby suppressing (allowing) an increase in the liquid level. Thereby, removal of the liquid and foreign material adhering to a nozzle plate can be made easy. Therefore, it is possible to stabilize the discharge after wiping.
In addition, since the nozzle is arranged on the bottom surface with the opposite stepped portion, in other words, the nozzle is sandwiched between the stepped portion, it becomes difficult to be affected by the outside air. Since the region can be moisturized, it is possible to suppress the liquid in the nozzle from being dried and increasing in viscosity (thickening). As a result, it is possible to prevent problems such as flight bends and delays in discharge timing, and problems such as irregular landing positions can be prevented.

  Application Example 2 In the liquid discharge head according to the application example described above, it is preferable that the wall surface of the stepped portion is formed perpendicular to the bottom surface on which the nozzle rows are arranged.

  According to the liquid ejection head of this application example, the wall surface of the step portion is formed perpendicular to the bottom surface on which the nozzle row is disposed. Thereby, when the wall surface of the stepped portion is formed perpendicular to the bottom surface, the width of the central portion in the depth direction of the stepped portion (in this case, the width of the bottom surface) increases with respect to the first direction. As a result, the liquid level rise of the wiped liquid can be suppressed, and the liquid and foreign matter adhering to the nozzle plate can be easily removed. Further, since it is possible to suppress the liquid in the nozzle from being thickened, it is possible to stabilize the discharge.

  Application Example 3 In the liquid ejection head according to the application example described above, the wall surface of the stepped portion is preferably formed in a tapered shape that opens the wall surface in the liquid ejection direction.

  According to the liquid ejection head of this application example, the wall surface of the stepped portion is formed in a tapered shape that opens the wall surface in the liquid ejection direction. Thereby, as the case where the width of the central portion in the depth direction of the stepped portion increases with respect to the first direction, the taper angle is constant and the width of the bottom surface increases with respect to the first direction, the taper angle Gradually opens with respect to the first direction, the width of the bottom surface is constant, the taper angle gradually opens with respect to the first direction, and the width of the bottom surface also increases with respect to the first direction. There is a form to do. In any case, since the wall surface is tapered, the wiper can smoothly enter the bottom surface as compared with the case where the wall surface is vertical. The liquid and foreign matter adhering to the plate can be easily removed. Further, since it is possible to suppress the liquid in the nozzle from being thickened, it is possible to stabilize the discharge.

  Application Example 4 In the liquid ejection head according to the application example described above, it is preferable that the wall surface is subjected to a hydrophilic treatment and the bottom surface is subjected to a water repellency treatment.

  According to the liquid discharge head of this application example, the wall surface is subjected to hydrophilic treatment, and the bottom surface on which the nozzle row is disposed is subjected to water repellency treatment, so that the wetness of the bottom surface around the nozzle row after wiping is achieved. Prevents the discharged liquid from being pulled by the non-uniform liquid reservoir and the liquid meniscus from stabilizing in the nozzle due to the non-uniform liquid reservoir. Therefore, the liquid can be discharged perpendicularly to the bottom surface without causing a flying curve of the liquid, and the discharge can be stabilized.

  Application Example 5 A liquid discharge apparatus according to this application example includes any one of the liquid discharge heads described above.

  According to the liquid discharge apparatus of this application example, by providing any of the liquid discharge heads described above, the liquid level of the wiped liquid is suppressed during wiping, and the liquid and foreign matter attached to the nozzle plate are removed. In addition, since it is possible to prevent the liquid in the nozzle after wiping from being thickened, it is possible to stabilize discharge. In addition, it is possible to further stabilize the discharge by performing hydrophilic treatment on the wall surface and water-repellent treatment on the bottom surface. Thereby, it is possible to realize a liquid ejection apparatus that improves the drawing quality.

1 is a schematic diagram illustrating a configuration of a printer according to a first embodiment. Schematic which shows an example of a structure of a head mechanism and a maintenance mechanism. FIG. 3 is a schematic plan view of a step portion and a bottom surface of the discharge head as viewed from the discharge direction. Sectional drawing of a step part and a bottom face. Sectional drawing of a step part and a bottom face. The figure which shows the state which wipes off the level | step-difference part and bottom face in the cross-sectional position shown to FIG. 4A with a wiper. The figure which shows the state which wipes off the level | step-difference part and bottom face in the cross-sectional position shown to FIG. 4B with a wiper. FIG. 9 is a schematic plan view of a step portion and a bottom surface of a discharge head according to a second embodiment viewed from a discharge direction. Sectional drawing of a step part and a bottom face. Sectional drawing of a step part and a bottom face. FIG. 10 is a schematic plan view of a stepped portion and a bottom surface of a discharge head according to a third embodiment viewed from a discharge direction. Sectional drawing of a step part and a bottom face. Sectional drawing of a step part and a bottom face. FIG. 10 is a schematic plan view of a step portion and a bottom surface of a discharge head according to a fourth embodiment viewed from a discharge direction. Sectional drawing of a step part and a bottom face. Sectional drawing of a step part and a bottom face. Sectional drawing of the level | step-difference part and bottom face of the discharge head which concerns on 5th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, each member in each drawing is illustrated with a scale different from the actual scale for each member in order to make the size recognizable on the drawing.

[First Embodiment]
FIG. 1 is a schematic diagram illustrating a configuration of a printer 1 according to the first embodiment. An outline of the configuration of the printer 1 will be described with reference to FIG.
A printer 1 as a liquid ejection apparatus according to the present embodiment schematically includes a paper feed mechanism 2, an ink supply mechanism 3, a control unit 4, a head mechanism 5, a maintenance mechanism 7 (see FIG. 2), and the like. Has been.

  The paper feed mechanism 2 includes a paper feed motor (PF motor) 21 and a paper feed roller 22 to which a driving force from the paper feed motor 21 is transmitted. In the present embodiment, roll paper P as a print medium is set on the paper feed roller 22. The roll paper P is not limited, and a regular printing paper may be used.

  The ink supply mechanism 3 includes a cartridge holder 31, a pressure pump 32, an ink supply path 33, an ink cartridge 34, and the like. The cartridge holder 31 is attached to a chassis (not shown), for example. An ink cartridge 34 is detachably attached to the cartridge holder 31. Therefore, the printer 1 of the present embodiment has a so-called off-carriage type configuration.

  When supplying ink (corresponding to liquid), the pressurizing pump 32 is operated, and air is pumped into the ink cartridge 34 to crush the ink pack (not shown), thereby pushing the ink into the ink supply path 33. It is configured as follows.

  The control unit 4 includes a CPU, a memory (ROM, RAM, nonvolatile memory, etc.), an ASIC (Application Specific Integrated Circuit), a bus, a timer, an interface, etc. (all not shown). The control unit 4 receives signals from various sensors, and based on the signals from the sensors, a motor such as a paper feed motor 21, a pressure pump 32, a suction pump (not shown), a head mechanism 5, The drive of the maintenance mechanism 7 (see FIG. 2) and the like is controlled in an integrated manner.

  In addition, data and programs stored in the memory are executed by the CPU, and various components of the control unit 4 cooperate to realize various functional configurations. In the present embodiment, the memory includes a piezoelectric drive unit (not shown) that drives a piezoelectric element (not shown) of the liquid discharge head 50, which will be described later, and the liquid discharge head 50 during printing and maintenance. A program and data for controlling the driving of the head driving mechanism 55 (see FIG. 2) that moves the head and the like, and the wiper driving mechanism 75 (see FIG. 2) that drives the maintenance mechanism 7 during maintenance are stored. Then, the control unit 4 reads out the program and data to instruct each driving driver (not shown) to eject ink from the liquid ejection head 50 and the wiper 70 of the maintenance mechanism 7 (FIG. 2). Wiping operation is performed according to (Ref.).

  The control unit 4 is connected to a computer PC or the like via the transmission / reception unit 41 to perform communication. Accordingly, when the printer 1 receives the print signal PS from the computer PC side, the printer 1 starts processing for printing based on the received print signal PS. In addition, when the printer 1 receives the maintenance signal MS from the computer PC side, the printer 1 starts a maintenance process based on the received maintenance signal MS.

  The head mechanism 5 of the present embodiment is arranged in a line for each ink color (each liquid type) in a direction perpendicular to the conveyance direction of a print medium such as paper, and has a length equivalent to the width dimension of the print medium. It is configured as a so-called line head. The head mechanism 5 includes a plurality of liquid discharge heads 50 (hereinafter referred to as discharge heads 50) in a direction perpendicular to the transport direction.

FIG. 2 is a schematic diagram illustrating an example of the configuration of the head mechanism 5 and the maintenance mechanism 7.
The printer 1 is provided with a maintenance mechanism 7 that performs maintenance on the head mechanism 5 (discharge head 50). The maintenance mechanism 7 is provided for each ejection head 50 for each ink color, and performs maintenance such as wiping on the ejection head 50. The maintenance mechanism 7 is provided adjacent to the nozzle row. On the other hand, the ejection head 50 is movable between the upward printing position of the paper feed roller 22 and the upward maintenance position of the maintenance mechanism 7 by the head driving mechanism 55.

  Further, the ejection head 50 is provided with a bottom surface 62 as a nozzle formation surface by the head driving mechanism 55 so that a wiping position approaching the maintenance mechanism 7 or a retracting position away from the maintenance mechanism 7 can be taken at the maintenance position. It is movable in a perpendicular exit / exit direction Dh. At the time of maintenance, the ejection head 50 is appropriately moved in the exit / retreat direction Dh according to the maintenance process, and is moved to the wiping position and the retracted position.

  The ejection head 50 includes a nozzle 51 that opens to the bottom surface 62, a reservoir 52 that temporarily stores ink, and a cavity 53 that communicates the nozzle 51 and the reservoir 52, and the reservoir 52 passes through the cavity 53. Thus, ink is supplied to the nozzle 51. Then, in response to an operation instruction from the control unit 4, the piezoelectric driving unit (piezoelectric element) operates to cause the cavity 53 to apply pressure to the ink, whereby the ink is ejected from the nozzle 51.

  The maintenance mechanism 7 includes a wiper 70, a moving body 72 having a support member 71 that supports the wiper 70, a wiper driving mechanism 75 that moves the moving body 72 in parallel with the bottom surface 62, a housing (not shown), and the like. It is configured with. The maintenance mechanism 7 can perform maintenance on the entire bottom surface 62 of the nozzles 51 arranged in a row.

  In the present embodiment, after the ejection head 50 is cleaned, the wiper 70 moves in the wiping direction Dw (direction along the nozzle row) in a state where the tip portion 701 is in contact with the upper surface of a step portion described later. Done. In the present embodiment, the wiping direction of the wiper 70 is one direction (wiping direction Dw). The wiper 70 after wiping moves in a direction opposite to the wiping direction Dw and stands by. Details of the wiping operation of the wiper 70 will be described later.

  The operation of the maintenance mechanism 7 is controlled by the control unit 4. The control unit 4 controls the movement of the ejection head 50 and the wiper 70 so as to displace the relative position between the ejection head 50 and the wiper 70. For example, the control unit 4 controls the head driving mechanism 55 to move the ejection head 50 in the withdrawal / retraction direction Dh and appropriately arrange the ejection head 50 at each position such as a retracted position and a wiping position. For example, when performing a wiping operation with the wiper 70, the ejection head 50 moves to the wiping position. Further, the control unit 4 controls the wiper driving mechanism 75 to drive the moving body 72 and move the wiper 70 in the wiping direction Dw parallel to the bottom surface 62. As described above, the control unit 4 performs control to displace the relative position between the ejection head 50 and the wiper 70 in accordance with the maintenance process.

FIG. 3 is a schematic plan view of the stepped portion 6 and the bottom surface 62 of the ejection head 50 as viewed from the ejection direction. FIG. 4A is a cross-sectional view of the step portion 6 and the bottom surface 62. Specifically, FIG. 4A is a cross-sectional view taken along the line AA shown in FIG. FIG. 4B is a cross-sectional view of the step portion 6 and the bottom surface 62. Specifically, FIG. 4B is a cross-sectional view taken along the line BB shown in FIG.
The configuration of the stepped portion 6 will be described with reference to FIGS. 3, 4A, and 4B.

  As shown in FIGS. 3, 4 </ b> A, and 4 </ b> B, the nozzle 51 is formed on the nozzle substrate 60. Step portions 6 are formed on the nozzle substrate 60 so as to face each other by etching or the like. A plurality of nozzles 51 for ejecting ink are formed on the bottom surface 62 that connects the step portions 6 (connects the wall surface 61 of the step portion 6). In other words, the bottom surface 62 is a nozzle forming surface on which the nozzles 51 are formed.

  As shown in FIG. 3, the nozzles 51 are arranged at intervals in the direction perpendicular to the transport direction (first direction D), and are configured as nozzle rows. The opposing stepped portions 6 are formed so as to be symmetric with respect to a plane perpendicular to the bottom surface 62 passing through the center line X, where X is a virtual center line passing through the center of the nozzle row (nozzle 51). . In detail, the first direction D coincides with the wiping direction Dw when the wiper 70 performs wiping.

  The wall surface 61 of the step portion 6 of this embodiment is formed perpendicular to the bottom surface 62. In the present embodiment, the depth H of the stepped portion 6 is constant with respect to the first direction D. In addition, as a center part of the depth direction of the level | step-difference part 6, in FIG. 4A, it becomes the center part P1, for example, and it becomes the center part P2 in FIG. 4B.

  In FIG. 4A on the upstream side in the first direction D, the width of the opposite central portion P1 is defined as a width W1. And in FIG. 4B which becomes the downstream of the 1st direction D, let the width | variety of the opposing center part P2 be width W2. In this case, the width of the central portion has a relationship of width W1 <width W2. In other words, the width of the central portion increases uniformly with respect to the first direction D. As a result, the cross-sectional area surrounded by the step portion 6 and the bottom surface 62 increases with respect to the first direction D.

  In the present embodiment, the central portion in the depth direction of the stepped portion 6 is the central portion of each wall surface 61 of the stepped portion 6 that intersects the bottom surface 62 and the surface orthogonal to the center line X of the nozzle row. Further, the width of the central portion is a length connecting the central portions of the respective wall surfaces 61.

  FIG. 5A is a schematic diagram showing a state in which the stepped portion 6 and the bottom surface 62 at the cross-sectional position shown in FIG. FIG. 5B is a schematic diagram showing a state where the stepped portion 6 and the bottom surface 62 at the cross-sectional position shown in FIG. In other words, FIG. 5A shows a state of wiping on the upstream side in the first direction D. FIG. 5B shows a wiping state on the downstream side in the first direction D.

  As shown in FIGS. 5A and 5B, the wiper 70 has a wiping direction Dw (in the nozzle row) in a state where the tip 701 is brought into contact with the upper surface 600 of the stepped portion 6 with a predetermined pressing force during wiping. Move along the direction). Thus, the wiper 70 can scrape (wipe off) ink adhering to the upper surface 600, ink mist drifting inside the step, and the like. In the present embodiment, the front end 701 is set not to contact the bottom surface 62. Moreover, the wiper 70 of this embodiment uses a rubber-type wiper. However, the wiper 70 may be a cloth wiper.

  As shown in FIG. 5A, since the wiper 70 presses the tip portion 701 against the upper surface 600, the region of the tip portion 701 facing the bottom surface 62 moves in a state of entering the stepped portion 6. By this wiping operation, the wiper 70 moves in the wiping direction Dw, so that liquid (ink) can be collected in the cross section surrounded by the wall surface 61 and the bottom surface 62 of the stepped portion 6, and the collected liquid is collected by the wiper 70. By moving it, an operation of wiping off ink and dust adhering to the nozzle 51 is performed.

  And as shown in FIG. 5B, when it becomes the downstream of the 1st direction D, compared with the upstream (FIG. 5A), the width | variety of the center part of the level | step-difference part 6 will increase (the width | variety of the bottom face 62 will increase). Therefore, the region of the front end portion 701 facing the bottom surface 62 moves in a state where it further enters the stepped portion 6 (a state in which it approaches the bottom surface 62). As a result, ink and dust marks adhering to the nozzle 51 can be further wiped off. In addition, since the cross-sectional area surrounded by the step portion 6 and the bottom surface 62 is increased with respect to the first direction D, the increased ink can be released to the downstream side, thereby increasing the ink level. It is suppressed.

According to the embodiment described above, the following effects can be obtained.
(1) In the liquid ejection head 50 of the present embodiment, the depth H of the step portion 6 is constant with respect to the first direction D, and the central portion (for example, P1, P2) in the depth direction of the step portion 6 The width (for example, W1, W2) increases with respect to the first direction D (width W1 <width W2). As a result, the cross-sectional area surrounded by the step portion 6 and the bottom surface 62 increases with respect to the first direction D. Therefore, when wiping is performed in the first direction D with the wiper 70, the wiped ink can easily flow in the first direction D, thereby suppressing (allowing) an increase in the liquid level of the ink. Accordingly, it is possible to easily remove ink and foreign matters attached to the nozzle 51 and the bottom surface 62. Therefore, it is possible to stabilize the discharge after wiping.

  (2) In the liquid ejection head 50 of the present embodiment, the nozzle 51 is arranged on the bottom surface 62 with the opposed step portions 6. In other words, since the nozzle 51 is sandwiched between the stepped portions 6, it becomes difficult to be affected by outside air, and the area of the nozzle 51 can be moisturized after wiping, so that the ink in the nozzle 51 is dried. It is possible to suppress thickening. Thereby, when the nozzle 51 ejects ink intermittently, it is possible to prevent problems such as flight bends and ejection timing delays, and to prevent problems such as irregular landing positions. Can be stabilized.

  (3) In the liquid ejection head 50 of the present embodiment, the wall surface 61 of the stepped portion 6 is formed perpendicular to the bottom surface 62 where the nozzle row is disposed. When the wall surface 61 of the step portion 6 is formed perpendicular to the bottom surface 62, the width of the center portion in the depth direction of the step portion 6 (in this case, the width of the bottom surface 62) is relative to the first direction D. As a result, the rise in the liquid level of the wiped ink can be suppressed, ink and foreign matters adhering to the nozzle 51 and the bottom surface 62 can be easily removed, and the ejection can be stabilized.

  (4) The liquid ejection apparatus (printer 1) of the present embodiment includes the above-described liquid ejection head 50, and suppresses the rise in the liquid level of the wiped ink during wiping, and adheres to the nozzles 51 and the bottom surface 62. Ink and foreign matter can be easily removed, and the ejection can be stabilized. Thereby, it is possible to realize a liquid ejection apparatus (printer) that improves drawing quality.

[Second Embodiment]
FIG. 6 is a schematic plan view of the stepped portion 6A and the bottom surface 65 of the ejection head 50A according to the second embodiment viewed from the ejection direction. FIG. 7A is a cross-sectional view of the stepped portion 6A and the bottom surface 65. FIG. Specifically, FIG. 7A is a CC cross-sectional view shown in FIG. FIG. 7B is a cross-sectional view of the stepped portion 6A and the bottom surface 65. Specifically, FIG. 7B is a cross-sectional view taken along line EE shown in FIG.

In the liquid ejection head 50A according to the second embodiment, the shape of the stepped portion 6A is different from the shape of the stepped portion 6 of the first embodiment. Other than that, it is comprised similarly to 1st Embodiment.
The configuration of the stepped portion 6A will be described with reference to FIGS. 6, 7A, and 7B.

  In the step portion 6A of the present embodiment, the wall surface 64 of the step portion 6A is formed in a tapered shape that opens the wall surface 64 in the ink ejection direction. In addition, a plurality of nozzles 51 that eject ink are formed on the bottom surface 65 that connects the stepped portions 6A (connects the wall surface 64 of the stepped portion 6A). Note that the depth H of the stepped portion 6A is the same as the depth H of the stepped portion 6 of the first embodiment in this embodiment.

  As shown in FIG. 7A, which is a CC cross section of FIG. 6, on the upstream side in the first direction D, when the angle formed by the straight line perpendicular to the bottom surface 65 and the wall surface 64 is a taper angle, The taper angle is θ1. The taper angle θ1 is constant with respect to the first direction D. Further, the central portion in the depth direction of the stepped portion 6A is defined as a central portion P3. And let W3 be the width of the opposite central portion P3.

  As shown in FIG. 7B, which is an EE cross section of FIG. 6, on the downstream side in the first direction D, the taper angle formed by the straight line perpendicular to the bottom surface 65 and the wall surface 64 is the same as in FIG. 7A in this embodiment. And θ1. Moreover, let the center part of the depth direction of the level | step difference part 6A be the center part P4. And let W4 be the width of the opposite central portion P4.

  When comparing the width W3 and the width W4 of the central portion, the width of the central portion has a relationship of width W3 <width W4. In other words, the width of the central portion increases uniformly with respect to the first direction D. In the present embodiment, the width of the bottom surface 65 is increased.

  Although not shown with respect to the stepped portion 6A and the bottom surface 65 configured as described above, the wiper 70 has a predetermined pressing force on the top end 701 on the upper surface 600 of the stepped portion 6A, as in the first embodiment. Then, the wiping direction Dw (the direction along the nozzle row) is moved in the contacted state. Further, the tip portion 701 is set not to contact the bottom surface 65 during the movement. In addition, since it becomes the downstream (FIG. 7B) of the 1st direction D compared with the upstream (FIG. 7A), the width | variety of the center part of the level | step-difference part 6A increases (the width | variety of the bottom face 65 increases), Therefore The region of the front end portion 701 facing 65 moves in a state where it further enters the stepped portion 6A (a state close to the bottom surface 65).

According to the above-described embodiment, the same basic effects as those of the first embodiment can be obtained, and the following effects can be obtained.
(1) In the liquid ejection head 50A of the present embodiment, the wall surface 64 of the stepped portion 6A is formed in a tapered shape that opens the wall surface 64 in the ink ejection direction, and the width of the central portion in the depth direction of the stepped portion 6A is the first. 1 uniformly increases in the direction D (the taper angle θ1 is constant, and the width of the bottom surface 65 increases in the first direction D). As a result, the cross-sectional area surrounded by the step portion 6A and the bottom surface 65 increases with respect to the first direction D. Thereby, the rise in the liquid level of the wiped ink can be suppressed, and the ink and foreign matter adhering to the nozzle 51 and the bottom surface 65 can be easily removed. In particular, since the wall surface 64 has a tapered shape, it is easier to escape the increased ink than when the wall surface is vertical, and the tip portion 701 of the wiper 70 smoothly enters the bottom surface 65. In addition, it is possible to easily remove the ink and foreign matters adhering to the nozzle 51 and the bottom surface 65 by suppressing the rise in the liquid level of the wiped ink, including the fact that it becomes easy. Further, since it is possible to prevent the ink in the nozzle 51 from being thickened, it is possible to stabilize the ejection.

[Third Embodiment]
FIG. 8 is a schematic plan view of the stepped portion 6B and the bottom surface 67 of the ejection head 50B according to the third embodiment viewed from the ejection direction. FIG. 9A is a cross-sectional view of the stepped portion 6B and the bottom surface 67. FIG. Specifically, FIG. 9A is a cross-sectional view taken along the line FF shown in FIG. FIG. 9B is a cross-sectional view of the stepped portion 6 </ b> B and the bottom surface 67. Specifically, FIG. 9B is a GG cross-sectional view shown in FIG.

In the liquid discharge head 50B according to the third embodiment, the shape of the step portion 6B is different from the shape of the step portion 6 of the first embodiment. Other than that, it is comprised similarly to 1st Embodiment.
The configuration of the step portion 6B will be described with reference to FIGS. 8, 9A, and 9B.

  In the step portion 6B of this embodiment, the wall surface 66 of the step portion 6B is formed in a tapered shape that opens the wall surface 66 in the ink ejection direction. In addition, a plurality of nozzles 51 that eject ink are formed on the bottom surface 67 that connects the step portions 6B (connects the wall surface 66 of the step portion 6B). Note that the depth H of the stepped portion 6B is the same as the depth H of the stepped portion 6 of the first embodiment in this embodiment.

  As shown in FIG. 9A, which is an FF cross section in FIG. 8, when the angle formed by the straight line perpendicular to the bottom surface 67 and the wall surface 66 on the upstream side in the first direction D is a taper angle, The taper angle is θ2. In FIG. 9A, the central portion in the depth direction of the stepped portion 6B is defined as a central portion P5. The width of the opposite central portion P5 is W5.

  As shown in FIG. 9B, which is a GG cross section of FIG. 8, a taper angle formed by a straight line perpendicular to the bottom surface 67 and the wall surface 66 on the downstream side in the first direction D is θ3. In FIG. 9B, the central portion in the depth direction of the stepped portion 6B is defined as a central portion P6. And let W6 be the width of the opposite central portion P6.

  In the present embodiment, when the taper angles θ2 and θ3 are compared, a relationship of θ2 <θ3 is established. In other words, the taper angle is uniformly expanded along the first direction D. In the present embodiment, the width of the bottom surface 67 (the width in the direction perpendicular to the center line X) is also uniformly expanded along the first direction D. As a result, the width of the central portion has a relationship of width W5 <width W6. In other words, the width of the central portion increases uniformly with respect to the first direction D.

  Although not shown with respect to the stepped portion 6B and the bottom surface 67 configured as described above, the wiper 70 has a predetermined pressing force on the top end portion 701 on the upper surface 600 of the stepped portion 6B, as in the first embodiment. Then, the wiping direction Dw (the direction along the nozzle row) is moved in the contacted state. Further, the tip portion 701 is set not to contact the bottom surface 67 during the movement. In addition, when it becomes the downstream (FIG. 9B) of the 1st direction D, compared with the upstream (FIG. 9A), the width | variety of the center part of the level | step-difference part 6B increases (a taper angle increases and the width | variety of the bottom face 67). Therefore, the region of the front end portion 701 that faces the bottom surface 67 moves in a state where it further enters the stepped portion 6B (a state that approaches the bottom surface 67).

According to the above-described embodiment, the same basic effects as those of the first embodiment can be obtained, and the following effects can be obtained.
(1) In the liquid ejection head 50B of the present embodiment, the wall surface 66 of the stepped portion 6B is formed in a tapered shape that opens the wall surface 66 in the ink ejection direction, and the taper angle is uniform along the first direction D. It is expanding. Further, the width of the bottom surface 67 (the width in the direction perpendicular to the center line X) is also uniformly expanded along the first direction D. Thereby, the width of the central portion increases uniformly with respect to the first direction D. As a result, the cross-sectional area surrounded by the stepped portion 6B and the bottom surface 67 increases with respect to the first direction D. The width of the bottom surface 67 is uniformly expanded along the first direction D, and the wall surface 66 is tapered and uniformly expanded along the first direction D. Compared with the case where 66 is vertical, the ink level is more likely to escape, and the tip portion 701 of the wiper 70 can easily enter the bottom surface 67 direction. Ink and foreign matter adhering to the nozzle 51 and the bottom surface 67 can be easily removed. Further, since it is possible to prevent the ink in the nozzle 51 from being thickened, it is possible to stabilize the ejection.

[Fourth Embodiment]
FIG. 10 is a schematic plan view of the stepped portion 6C and the bottom surface 69 of the ejection head 50C according to the fourth embodiment viewed from the ejection direction. FIG. 11A is a cross-sectional view of the stepped portion 6C and the bottom surface 69. FIG. Specifically, FIG. 11A is a cross-sectional view taken along the line II shown in FIG. FIG. 11B is a cross-sectional view of the stepped portion 6C and the bottom surface 69. Specifically, FIG. 11B is a JJ sectional view shown in FIG.

In the liquid ejection head 50C according to the fourth embodiment, the shape of the stepped portion 6C is different from the shape of the stepped portion 6 of the first embodiment. Other than that, it is comprised similarly to 1st Embodiment.
The configuration of the stepped portion 6C will be described with reference to FIGS. 10, 11A, and 11B.

  In the step portion 6C of the present embodiment, the wall surface 68 of the step portion 6C is formed in a tapered shape that opens the wall surface 68 in the ink ejection direction. A plurality of nozzles 51 for ejecting ink are formed on the bottom surface 69 that connects the stepped portions 6C (connects the wall surface 68 of the stepped portion 6C). Note that the depth H of the stepped portion 6C is the same as the depth H of the stepped portion 6 in the first embodiment in this embodiment.

  As shown in FIG. 11A, which is an II cross section of FIG. 10, on the upstream side in the first direction D, when the angle formed by the straight line perpendicular to the bottom surface 69 and the wall surface 68 is a taper angle, The taper angle is θ4. In addition, in FIG. 11A, the central portion in the depth direction of the stepped portion 6C is defined as a central portion P7. And let W7 be the width of the opposite central portion P7.

  As shown in FIG. 11B, which is a JJ cross section of FIG. 10, on the downstream side in the first direction D, the taper angle formed by the straight line perpendicular to the bottom surface 69 and the wall surface 68 is θ5. In addition, in FIG. 11B, the central portion in the depth direction of the stepped portion 6C is defined as a central portion P8. And let W8 be the width of the opposite central portion P8.

  In this embodiment, when the taper angles θ4 and θ5 are compared, the relationship θ4 <θ5 is established. In other words, the taper angle is uniformly expanded along the first direction D. In the present embodiment, the width of the bottom surface 69 (the width in the direction perpendicular to the center line X) is a constant width in the first direction D. As a result, the width of the central portion has a relationship of width W7 <width W8. In other words, the width of the central portion increases uniformly with respect to the first direction D.

  Although not shown with respect to the stepped portion 6C and the bottom surface 69 configured as described above, the wiper 70 has a predetermined pressing force on the top end portion 701 on the upper surface 600 of the stepped portion 6C, as in the first embodiment. Then, the wiping direction Dw (the direction along the nozzle row) is moved in the contacted state. In addition, the tip 701 is set not to contact the bottom surface 69 during the movement. In addition, since it becomes the downstream (FIG. 11B) of the 1st direction D compared with the upstream (FIG. 11A), the width | variety of the center part of the level | step-difference part 6C increases (taper angle expands), Therefore The regions of the opposed tip portions 701 move in a state of entering further into the stepped portion 6C (a state of approaching the bottom surface 69).

According to the above-described embodiment, the same basic effects as those of the first embodiment can be obtained, and the following effects can be obtained.
(1) In the liquid ejection head 50C of the present embodiment, the wall surface 68 of the stepped portion 6C is formed in a tapered shape that opens the wall surface 68 in the ink ejection direction, and the taper angle is uniform along the first direction D. It is expanding. Further, the width of the bottom surface 69 (the width in the direction perpendicular to the center line X) is a constant width in the first direction D. Thereby, the width of the central portion increases uniformly with respect to the first direction D. As a result, the cross-sectional area surrounded by the stepped portion 6C and the bottom surface 69 increases with respect to the first direction D. Since the wall surface 68 has a tapered shape and the taper angle is uniformly expanded along the first direction D, the increased amount of ink can be easily released compared to the case where the wall surface 68 is vertical, and the wiper In addition, it is possible to easily remove ink and foreign matters adhering to the nozzle 51 and the bottom surface 69 by suppressing the rise in the liquid level of the wiped ink. Can do. Further, since it is possible to prevent the ink in the nozzle 51 from being thickened, it is possible to stabilize the ejection.

[Fifth Embodiment]
FIG. 12 is a cross-sectional view of the stepped portion 6A and the bottom surface 65 of the ejection head 50D according to the fifth embodiment.
The liquid ejection head 50D according to the fifth embodiment uses the liquid ejection head 50A of the second embodiment, and the stepped portion 6A and the bottom surface 65 are configured in the same manner as in the second embodiment. The difference is that the stepped portion 6A and the bottom surface 65 are processed.

  Specifically, in the present embodiment, the bottom surface 65 is subjected to water repellency treatment to form a water repellant layer 80. Further, the wall surface 64 of the stepped portion 6A is subjected to a hydrophilic treatment to form a hydrophilic layer 81.

  Also in this case, similarly to the above-described embodiment, the wiper 70 has the tip portion 701 in contact with the upper surface 600 of the stepped portion 6A with a predetermined pressing force in the wiping direction Dw (direction along the nozzle row). )

According to the above-described embodiment, the same basic effects as those of the first embodiment can be obtained, and the following effects can be obtained.
(1) According to the liquid ejection head 50D of the present embodiment, the wall surface 64 is subjected to hydrophilic processing, and the bottom surface 65 on which the nozzle row is disposed is subjected to water repellency processing. As a result, after wiping, the wetness of the bottom surface 65 around the nozzle row becomes uniform (uniform ink pool), so that the ejected ink is pulled by the non-uniform ink pool or the non-uniform ink pool. Since it is possible to prevent the stabilization of the meniscus of the ink in the nozzle 51 and the like, it is possible to discharge the ink perpendicularly to the bottom surface 65 without causing a flying curve of the ink, thereby stabilizing the discharge. Can be planned.

  (2) According to the liquid ejection head 50D of the present embodiment, when wiping with the wiper 70, the wiper 70 presses the front end portion 701 against the upper surface 600, so The region moves while entering the stepped portion 6A. However, since the tip portion 701 is set not to contact the bottom surface 65, the water-repellent layer 80 formed on the bottom surface 65 can be prevented from being scraped and scraped by the tip portion 701. Thereby, it is possible to maintain the wetness of the bottom surface 65 around the nozzle row being uniform (uniform ink pool) after wiping. Therefore, the stabilization of discharge can be maintained for a long time.

  (3) According to the liquid ejection apparatus provided with the liquid ejection head 50D of the present embodiment, the rise of the liquid level of the wiped ink is suppressed at the time of wiping, and the ink and foreign matters attached to the nozzle 51 and the bottom surface 65 are removed. In addition, since it is possible to prevent the ink in the nozzle 51 after wiping from being thickened, it is possible to stabilize ejection, and the wall surface 64 is subjected to hydrophilic treatment and the bottom surface 65 is subjected to water repellency treatment. As a result, it is possible to further stabilize the discharge. Accordingly, it is possible to realize a liquid ejection device that improves drawing quality.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the scope of the invention. A modification will be described below.

  In the liquid ejection head 50D according to the fifth embodiment, the wall surface 64 of the step portion 6A of the liquid ejection head 50A according to the second embodiment is subjected to a hydrophilic treatment, and the bottom surface 65 is subjected to a water repellency treatment. However, the present invention is not limited to this, and the same effect can be obtained by performing the same processing in the first embodiment, the third embodiment, and the fourth embodiment.

  In the liquid ejection head 50D according to the fifth embodiment, the wall surface 64 of the step portion 6A of the liquid ejection head 50A according to the second embodiment is subjected to a hydrophilic treatment, and the bottom surface 65 is subjected to a water repellency treatment. This processing is performed with uniform strength. However, the present invention is not limited to this, and the bottom surface 65 enhances the water repellency on the downstream side (wiping end side) in the first direction D, and the wall surface 64 is on the downstream side in the first direction D (wiping end side). In addition, the ink and foreign matters attached to the nozzle 51 and the bottom surface 65 can be easily removed by processing so as to increase the hydrophilicity. This also applies to the first embodiment, the third embodiment, and the fourth embodiment.

  The head mechanism 5 of the printer 1 is configured as a line head formed with a length equivalent to the width dimension of the print medium. However, the present invention is not limited to this, and the head mechanism may be configured as a normal head that performs printing while reciprocating in the forward / reverse direction perpendicular to the conveyance direction of the print medium. Also, a maintenance mechanism may be installed in correspondence with the head configured as described above.

  In the above-described embodiment, the tip portion 701 of the wiper 70 is set not to contact the bottom surface 62, but may be contacted. The tip portion 701 of the wiper 70 is in contact with the bottom surface 62, so that the ink and dust attached to the nozzle 51 can be directly wiped off.

  DESCRIPTION OF SYMBOLS 1 ... Printer as a liquid discharge apparatus, 6, 6A, 6B, 6C ... Step part, 50, 50A, 50B, 50C, 50D ... Liquid discharge head, 51 ... Nozzle, 61, 64, 66, 68 ... Wall surface, 62, 65, 67, 69 ... bottom surface, 70 ... wiper, 80 ... water-repellent layer, 81 ... hydrophilic layer, D ... first direction, H ... depth of stepped portion, P1-P8 ... central portion, W1- W8: width of the central portion, θ1-θ5: taper angle.

Claims (5)

A plurality of nozzles that discharge liquid are arranged on the bottom surface that connects the opposing stepped portions, and are arranged at intervals in the first direction,
A depth of the stepped portion is constant with respect to the first direction;
The liquid discharge head according to claim 1, wherein a width of a central portion in the depth direction of the stepped portion increases with respect to the first direction. The liquid discharge head according to claim 1,
A wall surface of the stepped portion is formed perpendicular to the bottom surface on which the nozzle row is disposed. The liquid discharge head according to claim 1,
The wall surface of the stepped portion is formed in a tapered shape that opens the wall surface in the liquid discharge direction. The liquid discharge head according to claim 2 or 3,
The wall surface is subjected to a hydrophilic treatment,
A liquid discharge head, wherein the bottom surface is subjected to water repellency treatment.   A liquid discharge apparatus comprising the liquid discharge head according to claim 1.

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