JP2007296696A - Droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer head capable of improving printing quality by causing ink droplets to land accurately at a predetermined position.
In a recording head 30 mounted on a head holder 9, nozzles 15 arranged in a staggered manner are formed on a nozzle plate 21 on the lowermost surface, and a nozzle surface 21a facing a recording medium P is formed. A plurality of protrusions 21b are formed in parallel with the carriage scanning direction (X direction) through the interval between adjacent nozzles 15. The nozzle surface 21a is partitioned by the two adjacent protrusions 21b, whereby a rectifying path 200 is formed, and the air flow generated by the scanning of the head holder 9 is rectified in parallel with the scanning direction of the head holder 9. .
[Selection] Figure 5

Description

  The present invention relates to a droplet discharge device capable of discharging droplets, and for, for example, causing an ink droplet discharged from a nozzle of an inkjet printer device or the like to land on a recording medium accurately at a predetermined position. Is.

  In the inkjet printer apparatus, as shown in FIG. 7, a recording head 30 having a nozzle surface 21 a having a plurality of nozzles 15 on the lowermost surface is mounted on a head holder 9 that functions as a carriage, and the nozzle surface 21 a faces the recording medium P. The carriage is slidably installed on a guide shaft (not shown). The carriage moves in the scanning direction, and an actuator having a piezoelectric deformation portion corresponding to the nozzle 15 is selectively driven to eject ink droplets from the corresponding nozzle 15 onto the recording medium, thereby printing on the recording medium. Is made.

  The ink jet printer apparatus scans the recording medium by moving the carriage in the scanning direction between the recording medium P and the nozzle surface 21a of the recording head 30 as shown in FIGS. There is a problem that an air flow occurs in the direction opposite to the scanning direction, and the ink droplets ejected from the nozzle 15 cause landing deviation due to the influence. In recent years, the ink droplets ejected from the nozzles 15 of the recording head 30 have become smaller in size in response to higher speeds and higher resolutions, and the ink droplets do not reach the recording medium due to the generation of air flow, resulting in missing dots. There was also the problem of waking up.

  Therefore, in patent document 1, the convex part is arrange | positioned surrounding the outer periphery of the nozzle plate in which the nozzle was formed, and the influence by the air flow in the moving direction of the carriage is reduced. Further, in Patent Document 2, each substantially conical protrusion is formed in the vicinity of each nozzle on the upstream side in the recording paper conveyance direction with respect to the nozzle (ink discharge hole in Patent Document 2). When the recording medium is transported and recorded, the air flow bypasses each protrusion and a swirl is generated downstream of the protrusion, so that a part of the air flow is offset and the entire air flow is weakened. Can do.

JP-A-9-39256 JP 2002-127424 A

  For example, it is conceivable to prevent ink droplet landing deviation or dot omission by shortening the landing time of the ink droplet on the recording medium P by shortening the distance between the recording medium P and the nozzle surface 21a. As the distance becomes shorter, the air flow between the recording medium P and the nozzle surface 21a becomes stronger and faster, and the landing deviation and dot dropout are promoted, which may promote the deterioration of the print quality. .

  Further, according to the inventors' experiments, the ink droplet landing deviation is larger as the nozzles are located at both ends in the Y direction perpendicular to the scanning direction of the recording head 30. This is because the air flow accompanying the carriage scan occurs parallel to the carriage scanning direction X and in the opposite direction to the scanning direction, but the distance between the nozzle surface 21a and the recording medium is as narrow as 1 mm to 2 mm, and as shown in FIG. In addition, since the air flow is diffused outward with less resistance toward the outer side of the nozzle surface 21a (both ends in the Y direction), the ink droplet landing accuracy is worse toward the both ends of the recording head 30 in the Y direction. There was a problem that it was easy to cause omission (FIG. 7B).

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the printing quality by causing ink droplets to land accurately at predetermined positions.

  According to the first aspect of the present invention, an ejection head having a plurality of arranged nozzles is mounted on a carriage, and the liquid is ejected from the nozzles as droplets onto the medium while the carriage scans along the medium. In the droplet discharge device, a plurality of rectifying paths extending substantially parallel to the scanning direction of the carriage are provided on at least both end portions of the nozzle row in the direction perpendicular to the scanning direction on the nozzle surface of the recording head. It is formed.

  According to a second aspect of the present invention, in the droplet discharge device according to the first aspect, the rectifying path passes between nozzles adjacent to the scanning direction of the plurality of nozzles in a vertical direction. To do.

  According to a third aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first and second aspects, the rectifying path extends from one end of the nozzle surface in the scanning direction to the other end opposite thereto. It is characterized by extending to the point.

  According to a fourth aspect of the present invention, in the liquid droplet ejection device according to any one of the first to third aspects, the rectifying path is formed in a convex shape between the adjacent nozzles. And

  According to a fifth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first to third aspects, the rectifying path is formed in a slit shape between the adjacent nozzles. And

  According to a sixth aspect of the present invention, in the liquid droplet ejection device according to any one of the first to fifth aspects, the plurality of arranged nozzles is a staggered arrangement.

  According to the first aspect of the present invention, in a droplet discharge device in which a carriage on which a discharge head having a plurality of arranged nozzles is mounted discharges onto a medium while scanning along the medium, the nozzle surface of the discharge head In the nozzle row, a plurality of rectification paths extending substantially in parallel with the scanning direction of the carriage are formed at least at both ends in the direction perpendicular to the scanning direction. The air flow between the nozzle surface and the nozzle surface is rectified in a direction substantially parallel to the carriage scanning direction and in the opposite direction to the scanning direction by passing through the rectifying path, and the droplet flying direction is substantially linearized. This prevents the landing deviation and dot omission and improves print quality.

  According to a second aspect of the present invention, in the liquid droplet ejection device according to the first aspect, the rectifying path is ejected from the nozzle because it passes between the nozzles adjacent to each other in the direction perpendicular to the scanning direction of the plurality of nozzles. The flying direction of the liquid droplet is almost linearized, and the landing deviation of the liquid droplet and the missing dot can be suppressed. Further, since the rectifying path is formed in accordance with the interval between the nozzles, the amount of air flow becomes equal, the landing deviation and the dot omission are suppressed, and the landing position of the liquid droplet is accurate and the accuracy can be improved.

  According to a third aspect of the present invention, in the liquid droplet ejection device according to the first or second aspect, the rectifying path extends from one end in the scanning direction of the nozzle surface to the other end on the opposite side. Since it is formed, rectification of the air flow between the medium and the nozzle surface can be ensured.

  According to a fourth aspect of the present invention, in the liquid droplet ejection device according to any one of the first to third aspects, the rectifying path is formed in a convex shape between the adjacent nozzles, so the medium and the nozzle The rectification of the air flow between the surfaces can be ensured.

  According to the invention described in claim 5, since the rectifying path is formed in a slit shape in the droplet discharge device according to any one of claims 1 to 3, the air flow between the medium and the nozzle surface is rectified. Can be ensured. In addition, the air flow between the nozzle surface and the medium flows through the slit-shaped rectifying path, and the air volume between the nozzle hole for ejecting droplets and the medium decreases. Easy to prevent.

  According to the invention described in claim 6, in the droplet discharge device according to any one of claims 1 to 5, the plurality of arranged nozzles are in a staggered arrangement, so that the nozzles can be densified. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is embodied in the ink jet printer apparatus 1 and its configuration will be described. In the following description, the side from which ink is ejected is the lower surface and the downward direction, and the opposite side is the upper surface and the upward direction. In FIG. 1, the left end side of the drawing is the left direction, the right end side is the right direction, the lower side of the drawing is the front side, and the upper side of the drawing is the rear side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, two guide shafts 6 and 7 are provided in parallel inside the ink jet printer apparatus 1, and the ink jet printer head 100 can slide on the guide shafts 6 and 7. It is attached. The ink jet printer head 100 includes a recording head 30 that performs recording by ejecting ink droplets from a nozzle 15 onto a recording medium P that is a recording medium, and an ink tank that stores each color ink in a substantially box-shaped head holder 9 that functions as a carriage. 40. The head holder 9 is connected to an endless belt 11 that is rotated by a motor 10. By driving the motor 10, the head holder 9 reciprocates in the width direction (X direction) of the recording medium P along the guide shafts 6, 7, and ink drops Is applied to the actuator 31 (FIGS. 3 and 4) of the recording head 30, so that ink is ejected as ink droplets from the nozzle 15 and printing is performed. For each scan, the recording medium P is fed in the Y direction orthogonal to the X direction by a transport device (not shown) provided in the ink jet printer apparatus 1.

  The ink jet printer apparatus 1 is provided with an ink cartridge 5 containing ink of each color, for example, four colors of black BK, cyan C, magenta M, and yellow Y, and each is provided with a flexible ink supply tube 8. The ink is stored in each ink color in the ink tank 40 and supplied to each nozzle 15 for each color. Further, a flushing receiving member 4 is provided on the left side of the inkjet printer apparatus 1, and a suction cap 2 and a wiper member 3 are provided on the right side, and a maintenance unit for restoring the ink discharge function of the recording head 30 is installed. Yes.

  The ink jet printer head 100 will be described with reference to FIG. In the ink jet printer head 100, a recording head 30 is fixed to the lower side of the bottom wall 9c of the substantially box-shaped head holder 9 by an adhesive (not shown). An ink storage chamber 40 for supplying ink to 30 and a heat radiating plate 41 for radiating heat generated by a drive circuit 49 described later are mounted. A relay circuit board 50 is installed on the uppermost surface of the head holder 9 by bridging a pair of side walls 9b of the head holder 9.

  The recording head 30 is similar to the known one described in Japanese Patent Application Laid-Open No. 2005-322850, and as shown in FIG. 3, a cavity unit 20 having a plurality of plates joined and having a nozzle plate 21 on the bottom surface, and a cavity unit The plate-type actuator 31 that selectively applies a discharge pressure to the ink in the ink 20 and a flexible flexible wiring member 39 are joined to the upper surface of the plate-type actuator 31. The flexible wiring member 39 has a drive circuit 49 mounted thereon, and has one end electrically connected to the actuator 31 and the other end parallel to the surface and drawn out in the X direction. The drive circuit 49 transmits print data to the actuator 31 to selectively drive the actuator 31. The drawn wiring member 39 passes through a slit (not shown) penetrating the bottom wall 9c of the head holder 9 as shown in FIG. Along the side wall (a wall extending in a direction perpendicular to the opposite side wall 9b) and extending upward, and is electrically connected to a connector (not shown) of the relay circuit board 50.

  The cavity unit 20 is configured as shown in FIG. The cavity unit 20 has a structure in which a total of six thin plate members of a nozzle plate 21, a spacer plate 22, two manifold plates 23a and 23b, a base plate 24, and a cavity plate 25 are overlapped and bonded with an adhesive from the lower side, In the embodiment, each of the plates 22 to 25 has a thickness of about 50 to 150 μm, the nozzle plate 21 is made of synthetic resin such as polyimide, and the other plates are made of 42% nickel alloy steel plate.

  In the nozzle plate 21 on the lowermost surface of the cavity unit 20, a plurality of nozzles 15 are arranged in a staggered manner along the long side direction (Y direction) of the nozzle plate 21, as shown in FIG. A large number of nozzles 15 having a minute diameter (about 20 μm) are formed at minute intervals in the Y direction, and five rows are arranged in the X direction. Each ink is supplied to each nozzle row from an ink supply port 17 described later. Further, when the lower surface side (side facing the recording medium P) of the nozzle plate 21 is a nozzle surface 21a, a plurality of protrusions 21b extending on the nozzle surface 21a in a direction (X direction) parallel to the carriage scanning direction. A rectifying path 200 is formed between the two protrusions 21b adjacent to each other in the Y direction. The protrusion 21b and the rectifying path 200 will be described in detail later.

  Further, as shown in FIGS. 3 and 4, a plurality of pressure chambers 16 corresponding to the nozzles 15 are staggered along the longitudinal direction (Y direction) of the cavity plate 25 in the cavity plate 25 disposed on the uppermost surface. In an array, five rows are arranged in the X direction. In the embodiment, each pressure chamber 16 is formed in an elongated shape in plan view, and the longitudinal direction thereof is bored along the short side direction (X direction) of the cavity plate 25. Each pressure chamber 16 has one end in the longitudinal direction communicating with the plurality of nozzles 15 and the other end communicating with a common ink chamber 14 described later.

  In the two manifold plates 23a and 23b, five common ink chambers 14 that are long along the long side direction (Y direction) are formed through the plate thickness so as to extend along each row of nozzles 15. Yes. That is, the common ink chamber (manifold chamber) 14 is formed by stacking the two manifold plates 23 a and 23 b and covering the upper surface with the base plate 24 and the lower surface with the spacer plate 22. Each of the common ink chambers 14 extends in the row direction of the pressure chambers 16 (the row direction of the nozzles 15) so as to overlap a part of the pressure chambers 16 when viewed in plan from the stacking direction of the plates.

  The base plate 24 has communication holes for communicating the common ink chamber 14 and the pressure chamber 16, and the spacer plate 22, the manifold plates 23 a and 23 b, and the base plate 24 are supplied with ink from the pressure chamber 16 to the nozzle 15. Each is provided with a communication hole 37. Further, four ink supply ports 17 are formed in the end portions on one short side of the cavity plate 25 and the base plate 24 so as to correspond to the upper and lower positions. The ink supplied from the ink tank 40 is supplied to one end of the common ink chamber 14 as an ink supply channel via the ink supply port 17. Then, the ink is distributed and supplied to each pressure chamber 16 via the communication hole of the base plate 24, and ink is selectively supplied from the pressure chamber 16 through the communication hole of each plate by selective driving of an actuator 31 described later. It is configured to reach the nozzle 15 corresponding to the chamber 16.

  Further, in contrast to the four lines of the ink supply ports 17, five lines of nozzles 15, pressure chambers 16, and common ink chambers 14 are provided because two nozzle lines that discharge black ink that is used frequently are provided. For this reason, the black ink is distributed from the single black ink supply port 17 to the two common ink chambers 14 and the pressure chambers 16 and is discharged from the nozzles 15.

  Further, although the cavity unit 20 is not in the present embodiment, a damper plate may be provided adjacent to the lower surface of the manifold plate 23a. In the damper plate, a damper chamber corresponding to the position and shape of the common ink chamber 14 is recessed, and the thin plate-like ceiling portion of the damper chamber is elastically deformed and vibrated, whereby the pressure fluctuation in the common ink chamber 14 is changed. Can be absorbed and attenuated to prevent crosstalk.

  The actuator 31 has a plurality of ceramic layers including the lowermost ceramic layer 31 a 1 covering each of the plurality of pressure chambers 16 in the same manner as the known one described in JP-A-2005-322850. This is a structure in which the chambers 16 are stacked in a direction perpendicular to the arrangement surface of the plurality of pressure chambers 16 and are integrally fired. The thickness of one ceramic layer is about 30 μm and is a piezoelectric ceramic such as PZT. On the upper surface (wide surface) of the ceramic layer 31b of the even-numbered stages from the bottom among the ceramic layers, narrow individual electrodes 33 are provided along the long side direction at locations corresponding to the pressure chambers 16 in the cavity unit 20. It is formed in a row. A common electrode 32 common to the plurality of pressure chambers 16 is formed on the upper surface (wide surface) of the odd-numbered ceramic layers 31a from the bottom. The common electrode 32 is connected to the ground potential. The individual electrodes 33 and the common electrode 32 are alternately arranged with at least one ceramic layer interposed therebetween except for the lowermost ceramic layer 31a1, and face each other.

  A connection terminal 36 connected to the individual electrode 32 and the common electrode 33 is formed on the uppermost surface of the actuator 31. The actuator 31 is bonded and fixed to the cavity unit 20 and the actuator 31 with the individual electrodes 32 and the pressure chambers 16 of the cavity unit 20 facing each other. A wiring pattern formed on the flexible wiring member 40 is connected to the connection terminal 36 on the uppermost surface of the actuator 31.

  The actuator 31 uses the ceramic layer portion between the individual electrode 32 and the common electrode 33 facing each other in the stacking direction of the plurality of ceramic layers as an energy generation unit, and the drive circuit 49 selectively selects the individual electrode 32 and the common electrode 33. By applying a voltage between the two, the energy generating portion corresponding to the applied individual electrode 32 is distorted in the stacking direction, and this displacement changes the volume of the pressure chamber 16 and pushes out the ink. 20 is discharged from the nozzle 15 through the communication hole 37 in the nozzle 20.

  Next, the rectifying path 200 will be described with reference to FIGS. FIG. 5 is a view of the ink jet printer head 100 as viewed from below, and FIG. 6 is an enlarged cross-sectional view of the nozzle plate 21. As shown in FIG. 5, the nozzle surface 21 a of the recording head 30 is exposed and fixed to the lower side of the head holder 9. Nozzles 15 arranged in a staggered manner in the Y direction are formed on the nozzle surface 21a, and the nozzle surfaces 21a are narrow and narrow as shown in FIG. 5B at both ends of the nozzle plate 21 in the Y direction. A plurality of protrusions 21b projecting from the recording medium P direction (lower side) and extending in parallel with the carriage scanning direction (X direction) are formed. The protruding portion 21b passes between adjacent Y directions of the nozzles 15 arranged in a staggered manner, and is provided so as to cut from one end of the nozzle plate 21 in the X direction to the other end.

  The rectifying path 200 is an air flow path formed by dividing the nozzle surface 21a by the protrusions 21b adjacent to each other in the Y direction. The rectifying path 200 is formed between the nozzle surface 21a generated when the carriage is scanned and the recording medium P. The air flow in the direction opposite to the scanning direction is guided through the rectifying path 200 in parallel to the X direction. In particular, since the rectifying path 200 is installed at both ends of the nozzle surface 21a in the Y direction, the X-direction air flow generated between the nozzle surface 21a and the recording medium P is near the both ends of the nozzle surface in the Y direction. Thus, it is possible to suppress the escape in the Y direction as in the prior art, and to generate parallel to the X direction.

  Since the protrusions 21 b are formed at an equal pitch corresponding to the pitch of the nozzles 15, the air flow through the rectifying path 200 can flow by an equal amount with respect to each nozzle 15, and ink droplet landing It is possible to improve the printing quality by improving the accuracy and reducing the number of missing dots. Further, if the protrusion 21b passes through at least the nozzles in the adjacent Y direction in parallel, the protrusion 21b can be effective in linearizing the flying direction of the ink droplets ejected from the nozzle 15. In the present embodiment, the rectifying path 200 is provided in the direction of both ends in the Y direction, in particular, where the air flow spreads, but of course, it may be provided on all the nozzle surfaces 21a including the central part.

  Further, the rectifying path 200 is formed not only in the range where the nozzles 15 are formed, but also on both ends in the Y direction of the nozzle surface 21a in the extending direction of the nozzle 15 row, thereby forming the rectifying path 200c. is doing. In this case, when the strength and speed of the air flow by the carriage scanning are large, the air flow that flows to the rectifying path 200c is further suppressed by the air flow that escapes outward, so that the landing deviation is reduced.

  The protrusion 21b and the protrusion 21c are narrow enough to pass through the interval between the adjacent nozzles 15. The height of the protrusion 21b and the protrusion 21c is the distance between the protrusion 21b and the recording medium P when the recording medium P faces the nozzle surface. If it is suitable for. In the embodiment, the protrusions 21b and 21c are cut from one end to the other end of the nozzle plate 21 in the X direction. However, the protrusions 21b and 21c are parallel to the scanning direction of the carriage and the nozzle 15 is perforated. If there is, it is not necessary to cut through.

  FIG. 6B shows another embodiment. In FIG. 6B, a plurality of slits 22 that are narrow and extend in parallel with the carriage scanning direction (X direction) are formed on the nozzle surface 21a at both ends in the Y direction. Similarly, the slit 22 passes between adjacent Y directions of the nozzles 15 arranged in a staggered pattern, and cuts from the X-direction end of the nozzle plate 21 to the other end. In FIG. 6B, the slit 22 serves as the rectifying path 200. Since the air flow between the recording medium P and the nozzle surface 21 a is concentrated in the slit 22, the air flow between the nozzle hole 15 and the recording medium P is reduced, and the ejected ink droplets are affected by the air flow. It is hard to receive and can prevent landing deviation and missing dots. Similarly to FIG. 6A, the slit 22 is formed not only in the range where the nozzle 15 is formed but also to the end of the nozzle plate 21 to form a rectifying path 200c. In FIG. 6B, since there are no protrusions 21b and 21c as in FIG. 6A, the distance between the recording medium P and the nozzle surface 21a can be made shorter than that in FIG. 6A. Further, the slit 22 may be formed so as to overlap the nozzle 15 instead of passing between the adjacent nozzles 15 as shown in FIG. 6B and 6C, the slit 22 is formed over the entire width of the nozzle plate 21 in the X direction. However, at least in the range where the nozzle 15 is formed, the slit 22 is not formed. Thus, it can play a role of rectifying the air flow.

In this way, a plurality of rectifying paths 200 extending in parallel with the carriage scanning direction (X direction) are formed on the nozzle plate 21 at least at both ends in the Y direction of the nozzle surface 21, so that air flow accompanying carriage scanning is achieved. However, it is rectified in the X direction over the front surface of the nozzle surface 21a, and the ejected ink droplet can be landed accurately at a predetermined position, so that the printing quality can be improved. As described above, the embodiments have been described with respect to the ink jet printer apparatus. However, the present invention forms a wiring or a terminal by discharging a colored liquid as a micro droplet or an apparatus that applies a colored liquid as a micro droplet. The present invention can also be applied to an apparatus, an apparatus for inspecting a test solution by discharging the test solution as fine droplets.

1 is a schematic diagram of an inkjet printer device 1. 2 is a cross-sectional view of the inkjet printer head 100 in the Y direction. FIG. 2 is a perspective view of a recording head 30. FIG. 2 is a side sectional view of the recording head 30. FIG. FIG. 2A is a diagram of an inkjet printer head 100 viewed from below. (B) It is a partial cross-section enlarged perspective view of the nozzle plate 21. (A) It is the cross-sectional enlarged view of the Y direction of the nozzle plate 21 of this embodiment of FIG. (B) It is a cross-sectional enlarged view of the Y direction of the nozzle plate 21 of other embodiment. (C) It is a cross-sectional enlarged view of the Y direction of the nozzle plate 21 of other embodiment. (A) It is a figure which shows the air flow of the conventional inkjet printer head 100. FIG. (B) It is a cross-sectional enlarged view of the conventional nozzle plate 21 in the Y direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 9 Head holder 15 Nozzle 21 Nozzle plate 21a Nozzle surface 21b Protrusion part 21c Protrusion part 22 Slit 30 Recording head 100 Inkjet printer head 200 Rectification path

Claims (6)

In a liquid droplet ejection apparatus that ejects a liquid from the nozzles as liquid droplets onto a medium while an ejection head having a plurality of arranged nozzles is mounted on a carriage, and the carriage scans along the medium,
On the nozzle surface of the ejection head, a plurality of rectification paths extending substantially in parallel with the scanning direction of the carriage are formed at least at both ends in the direction perpendicular to the scanning direction in the nozzle row. A droplet discharge apparatus characterized by the above.   2. The droplet discharge device according to claim 1, wherein the rectifying path passes between nozzles adjacent to each other in a direction perpendicular to the scanning direction of the plurality of nozzles.   3. The droplet discharge device according to claim 1, wherein the rectifying path is formed to extend from one end of the nozzle surface in the scanning direction to the other end opposite thereto. .   The droplet discharge device according to claim 1, wherein the rectifying path is formed in a convex shape between the adjacent nozzles.   The droplet discharge device according to claim 1, wherein the rectifying path is formed in a slit shape between the adjacent nozzles. The droplet discharge device according to claim 1, wherein the plurality of arranged nozzles is a staggered arrangement.

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