CN109228658B - Liquid ejecting head and liquid ejecting apparatus - Google Patents

Abstract

The invention provides a liquid ejecting head and a liquid ejecting apparatus capable of improving ejection stability. Comprising: a first head chip and a second head chip stacked in the Y direction; a first flow path member disposed in a-Y direction with respect to the first head chip and having a first ink flow path communicating with the first head chip; and a second flow path member (51B) which is arranged in the + Y direction with respect to the second head chip and has a second ink flow path (155) communicating with the second head chip, wherein the first flow path member is provided with a first bubble discharge flow path for communicating the inside and the outside of the first ink flow path, and the second flow path member (51B) is provided with a second bubble discharge flow path (160) for communicating the inside and the outside of the second ink flow path (155).

Description

Liquid ejecting head and liquid ejecting apparatus

Technical Field

The present invention relates to a liquid ejecting head and a liquid ejecting apparatus.

Background

Conventionally, there is an ink jet printer including an ink jet head as a device for ejecting ink in a droplet form onto a recording medium such as recording paper to record an image or a character on the recording medium. The inkjet head is configured by mounting a plurality of ejection modules corresponding to the respective colors on a carriage, for example.

The ejection module includes a head chip for ejecting ink, a manifold having an ink flow path for supplying ink to the head chip, and the like. For example, patent document 1 listed below discloses a configuration in which a plurality of head chips are mounted on a single injection module in order to realize high-resolution printing, high-speed printing, and the like.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-208226.

Disclosure of Invention

Problems to be solved by the invention

However, when air is entrained in the ink flowing through the ink flow path, the ink may become air bubbles and stay in the ink. If the air bubbles reach the head chips, the ink is insufficiently filled in each head chip, and the discharge of the ink from the nozzle hole becomes unstable.

The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid ejecting head and a liquid ejecting apparatus capable of improving ejection stability.

Means for solving the problems

In order to solve the above problem, a liquid ejecting head according to an aspect of the present invention includes: a first head chip and a second head chip which are stacked in a first direction and which eject a liquid; a first channel member which is disposed on the opposite side of the first head chip from the second head chip in the first direction and has a first liquid channel communicating with the first head chip; and a second flow path member which is disposed on the opposite side of the second head chip from the first head chip in the first direction and has a second liquid flow path communicating with the second head chip, wherein the first flow path member is provided with a first bubble discharge flow path for communicating the inside and the outside of the first liquid flow path, and the second flow path member is provided with a second bubble discharge flow path for communicating the inside and the outside of the second liquid flow path.

With this configuration, the bubbles accumulated in the first liquid flow path and the second liquid flow path can be discharged through the first bubble discharge flow path and the second bubble discharge flow path, respectively. Therefore, it is possible to suppress entry of air bubbles into each head chip and improve the filling property of the liquid into each head chip. This improves the ejection stability.

In the liquid ejecting head according to the above aspect, the first head chip may have a first pressure fluctuation chamber that gives pressure fluctuation to the liquid, the second head chip may have a second pressure fluctuation chamber that gives pressure fluctuation to the liquid, the first head chip and the second head chip may be provided with ejection orifice plates in which ejection orifices that communicate with the first pressure fluctuation chamber and the second pressure fluctuation chamber, respectively, are formed,

in the injection orifice plate, a first discharge orifice communicating with the first bubble discharge channel and a second discharge orifice communicating with the second bubble discharge channel are opened in an injection surface in which the injection orifice is opened.

According to this configuration, since the ejection hole and each of the ejection holes are open on the same surface (ejection surface), the ejection hole and each of the ejection holes can be covered with one cap in cases where the ejection surface is sealed with a cap at the time of filling of liquid or at the time of stopping of printing operation, for example. Therefore, the maintainability can be improved.

In the liquid ejecting head according to the above aspect, the first channel member may have an inflow port that connects a liquid supply source and the first liquid flow channel, a communication flow channel that communicates the first liquid flow channel and the second liquid flow channel may be disposed between the first channel member and the second channel member, and the second discharge hole may have an inner diameter smaller than an inner diameter of the first discharge hole.

In the second liquid flow path, a part of the liquid in the first liquid flow path is supplied through the communication flow path. In this case, the second liquid flow path is located on the downstream side of the first liquid flow path, and therefore, the pressure in the second liquid flow path is more likely to be higher than the pressure in the first liquid flow path.

In this way, according to this aspect, the surface tension acting on the inner surface of the second discharge port can be made higher than the surface tension acting on the inner surface of the first discharge port by making the inner diameter of the second discharge port smaller than the inner diameter of the first discharge port. This makes it easy to stabilize the meniscus in the second discharge hole, and prevents the liquid from leaking through the second discharge hole.

Further, by stabilizing the meniscus in the second discharge hole, it is possible to suppress, for example, the meniscus from being broken by a negative pressure generated in the second head chip and the outside air (air) from entering the second head chip through the second discharge hole when the liquid jet head is used (at the time of liquid ejection). Therefore, the air entering from the second discharge hole is prevented from becoming bubbles and staying in the head chip, and the ejection stability can be improved.

In the liquid ejecting head according to the aspect of the invention, the second head chip may have an ejection area in which second pressure fluctuation chambers for applying pressure fluctuation to the liquid are arranged in a second direction intersecting the first direction, the communication flow paths may be arranged in a pair in the second direction at portions on both sides with respect to the ejection area, and the second bubble discharge flow path may be communicated with the second liquid flow path at a center portion between the pair of communication flow paths in the second direction.

According to this aspect, the distances from the respective communication channels to the second bubble discharge channel are set to be equal to each other. Therefore, the bubbles retained in the second liquid flow path can be uniformly pushed out toward the second bubble discharge flow path from both sides in the second direction while the liquid flows through the second liquid flow path from each of the communication flow paths to the center portion in the second direction. This can more reliably suppress the entry of air bubbles into the second head chip.

In the liquid ejecting head according to the above aspect, a filter for filtering the liquid may be disposed in the second bubble discharge channel.

According to this aspect, by increasing the flow path resistance in the second bubble discharge flow path by the filter, it is possible to suppress the meniscus in the second discharge hole from being broken by pressure fluctuations in the second bubble discharge flow path due to the flow of liquid from the upstream side, the ejection of liquid from the nozzle holes, and the like. This makes it easy to stabilize the meniscus in the second discharge hole, and prevents the liquid from leaking through the second discharge hole.

A liquid ejecting apparatus according to an aspect of the present invention includes the liquid ejecting head according to the above aspect.

According to this aspect, a liquid ejecting apparatus having excellent ejection performance can be provided.

ADVANTAGEOUS EFFECTS OF INVENTION

According to an aspect of the present invention, the discharge stability can be improved.

Drawings

Fig. 1 is a schematic configuration diagram of an inkjet printer according to an embodiment;

fig. 2 is a perspective view of an ink jet head according to an embodiment;

fig. 3 is a partially exploded perspective view of the ink jet head according to the embodiment;

fig. 4 is an exploded perspective view of the base member and the first ejection module in the inkjet head according to the embodiment;

fig. 5 is an exploded perspective view of a first injection module according to the embodiment;

fig. 6 is an exploded perspective view of the discharge portion according to the embodiment;

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

fig. 8 is an exploded perspective view of the first channel member according to the embodiment, the first channel member being developed in the + Y direction from the first channel plate;

fig. 9 is a front view of the first flow path plate according to the embodiment as viewed from the + Y direction;

FIG. 10 is a cross-sectional view of a first emission module corresponding to line X-X of FIG. 8;

FIG. 11 is an enlarged view of section XI of FIG. 10;

fig. 12 is an exploded perspective view of the first channel member according to the embodiment, the first channel member being developed in the-Y direction from the first channel plate;

fig. 13 is a front view of the second flow path plate according to the embodiment as viewed from the + Y direction;

fig. 14 is a sectional view taken along the line XIV-XIV of fig. 2.

Detailed Description

Embodiments according to the present invention will be described below with reference to the drawings. In the following embodiments, an ink jet printer (hereinafter, simply referred to as a printer) that records on a recording medium with ink (liquid) will be described as an example. In the drawings used in the following description, the scale of each member is appropriately changed so that each member can be recognized.

[ Printer ]

Fig. 1 is a schematic configuration diagram of the printer 1.

As shown in fig. 1, the printer 1 of the present embodiment includes a pair of transport mechanisms 2 and 3, an ink supply mechanism 4, inkjet heads 5A and 5B, and a scanning mechanism 6. In the following description, a rectangular coordinate system of X, Y, Z will be used as necessary. In this case, the X direction (second direction) coincides with the conveyance direction (sub-scanning direction) of the recording medium P (e.g., paper). The Y direction (first direction) coincides with the scanning direction (main scanning direction) of the scanning mechanism 6. The Z direction indicates a height direction (gravity direction) orthogonal to the X direction and the Y direction. In the following description, the arrow direction in the drawings is referred to as the plus (+) direction and the direction opposite to the arrow is referred to as the minus (-) direction among the X direction, the Y direction and the Z direction. In the present embodiment, the + Z direction corresponds to the upward direction of gravity, and the-Z direction corresponds to the downward direction of gravity.

The transport mechanisms 2,3 transport the recording medium P in the + X direction. Specifically, the conveying mechanism 2 includes a grid roller (grid roller)11 extending in the Y direction, a pinch roller (pinch roller)12 extending parallel to the grid roller 11, and a driving mechanism (not shown) such as a motor for rotating the grid roller 11 around the shaft. Similarly, the conveyance mechanism 3 includes a grid roller 13 extending in the Y direction, a pinch roller 14 extending parallel to the grid roller 13, and a drive mechanism (not shown) for rotating the grid roller 13 around the shaft.

The ink supply mechanism 4 includes an ink tank 15 for storing ink, and an ink pipe 16 for connecting the ink tank 15 and the inkjet heads 5A and 5B.

In the present embodiment, a plurality of ink tanks 15 are arranged in the X direction. In each ink tank 15, four colors of ink, for example, yellow, magenta, cyan, and black, are contained.

The ink pipe 16 is, for example, a flexible hose having flexibility. The ink tubes 16 connect the ink tanks 15 and the ink jet heads 5A and 5B.

The scanning mechanism 6 reciprocally scans the inkjet heads 5A,5B in the Y direction. Specifically, the scanner unit 6 includes a pair of guide rails 21 and 22 extending in the Y direction, a carriage 23 movably supported by the pair of guide rails 21 and 22, and a drive mechanism 24 for moving the carriage 23 in the Y direction.

The drive mechanism 24 is disposed between the guide rails 21, 22 in the X direction. The drive mechanism 24 includes a pair of pulleys 25, 26 arranged at intervals in the Y direction, an endless belt 27 wound around the pair of pulleys 25, 26, and a drive motor 28 for driving and rotating the one pulley 25.

The carriage 23 is connected to an endless belt 27. The plurality of inkjet heads 5A,5B are mounted on the carriage 23 in a state of being aligned in the Y direction. The inkjet heads 5A and 5B are configured to be able to eject two colors of ink for each of the inkjet heads 5A and 5B. Therefore, in the printer 1 of the present embodiment, the ink jet heads 5A and 5B are configured to discharge two different colors of ink, and to be able to discharge four colors of ink, i.e., yellow, magenta, cyan, and black.

< ink jet head >

Fig. 2 is a perspective view of the ink-jet head 5A. Fig. 3 is a partially exploded perspective view of the inkjet head 5A. The inkjet heads 5A and 5B are formed of the same composition except for the color of the supplied ink. Therefore, in the following description, the inkjet head 5A will be described, and the description of the inkjet head 5B will be omitted.

As shown in fig. 2 and 3, the inkjet head 5A of the present embodiment is configured such that the ejection modules 30A and 30B (see fig. 3), the damper 31, the nozzle plate 32 (see fig. 2), the nozzle guard 33, and the like are mounted on the base member 38.

(base member)

Fig. 4 is an exploded perspective view of the inkjet head 5A, the base member 38, and the first ejection module 30A.

As shown in fig. 4, the base member 38 is formed in a plate shape having the Z direction as the thickness direction and the X direction as the longitudinal direction. The base member 38 includes a base main body portion 41 that holds the injection modules 30A and 30B, and a carriage fixing portion 42 that fixes the base member 38 to the carriage 23 (see fig. 1). In addition, in the present embodiment, the base member 38 is integrally formed of a metal material.

The base body portion 41 is formed with module accommodating portions (a first module accommodating portion 44A and a second module accommodating portion 44B). The module accommodating portions 44A,44B are formed in two rows in the Y direction corresponding to the injection modules 30A, 30B. Each of the module accommodating portions 44A,44B penetrates the base body portion 41 in the Z direction. The corresponding injection modules 30A,30B can be inserted into the module accommodating portions 44A,44B, respectively. That is, the injection modules 30A and 30B are held by the base body 41 in a state of rising from the base member 38 in the + Z direction by inserting the-Z direction end portions into the module accommodating portions 44A and 44B.

In the base body portion 41, a partition portion 46 that partitions the module accommodating portions 44A,44B is formed in a portion located between the module accommodating portions 44A, 44B. A pair of short side portions 45a,45b facing each other in the X direction in the base body portion 41 is formed with a protruding wall 47 protruding inward in the X direction. A projecting wall 47 and a projecting wall 47 facing each other in the X direction are formed as a set in each of the respective module accommodating portions 44A, 44B.

The first short side portion 45a is provided with a first urging member 48. The first biasing member 48 is provided corresponding to each of the module accommodating portions 44A, 44B. Each first biasing member 48 is formed in a leaf spring shape interposed between the first short side portion 45a and each injection module portion 30A, 30B. The first biasing members 48 bias the injection mold block portions 30A and 30B toward the second short side portion 45B (-X direction).

The carriage fixing portion 42 extends from the + Z direction end of the base main body portion 41 toward the XY plane. The carriage fixing portion 42 is formed with a mounting hole or the like for mounting the base member 38 to the carriage 23 (see fig. 1).

(Ejection Module)

As shown in fig. 3, the injection modules 30A and 30B are formed in a plate shape with the Y direction as the thickness direction. The ejection modules 30A and 30B are configured to eject ink supplied from the ink tank 15 (see fig. 1) toward the recording medium P. The injection modules 30A and 30B are mounted on the base member 38 at intervals in the Y direction.

In the ink jet head 5A of the present embodiment, the ejection modules 30A and 30B eject ink of one color. The number of the ejection modules 30A and 30B mounted on the base member 38, and the color and type of ink ejected from the ejection modules 30A and 30B can be changed as appropriate. The injection modules 30A and 30B having the same configuration are mounted on the base member 38 in the Y direction in opposite directions to each other. Therefore, in the following configuration, the first injection module 30A will be described as an example.

Fig. 5 is an exploded perspective view of the first injection module 30A.

As shown in fig. 5, the first injection module 30A mainly includes the discharge portion 50, and the first channel member 51A and the second channel member 51B facing each other in the Y direction with the discharge portion 50 interposed therebetween.

(discharge part)

Fig. 6 is an exploded perspective view of the discharge portion 50.

As shown in fig. 6, the ejection section 50 has a first head chip 52A, and a second head chip 52B stacked in the + Y direction with respect to the first head chip 52A. Each of the head chips 52A and 52B is a so-called edge shooter type head chip that ejects ink from an end of the ejection channel 57 in the extending direction (Z direction) described later.

The first head chip 52A is configured by overlapping the first actuator plate 55 and the first cover plate 56 in the Y direction.

The first actuator plate 55 is a piezoelectric substrate formed of PZT (lead zirconate titanate) or the like. The first actuator plate 55 is set such that the polarization direction is unidirectional in the thickness direction (Y direction). Further, the first actuator plate 55 may also be formed by laminating two piezoelectric substrates whose polarization directions are different in the Y direction (a so-called chevron (chevron) type).

On a surface (hereinafter, referred to as a "surface") of the first actuator plate 55 facing the-Y direction, a plurality of channels 57,58 that are open are provided in parallel at intervals in the X direction. Each of the passages 57,58 is formed linearly in the Z direction. Each of the passages 57,58 opens on the-Z-direction end face of the first actuator plate 55. Furthermore, the channels 57,58 may also extend obliquely with respect to the Z-direction.

Fig. 7 is a sectional view taken along line VII-VII of fig. 6.

As shown in fig. 6 and 7, the plurality of channels 57 and 58 are discharge channels 57 filled with ink and non-discharge channels 58 not filled with ink. The discharge channels 57 and the non-discharge channels 58 are alternately arranged in the X direction. Each of the passages 57,58 is partitioned in the X direction by a drive wall 61 formed by the first actuator plate 55, respectively. Further, on the inner surfaces of the passages 57,58, drive electrodes 59 are formed. The drive electrode 59 is a drive terminal (not shown) connected to a surface of the first actuator plate 55 at an end portion in the + Z direction of the first actuator plate 55.

The first cover 56 is formed in a rectangular shape in a plan view seen from the Y direction. The first cover plate 56 is joined to the surface of the first actuator plate 55 in a state where the + Z direction end of the first actuator plate 55 is projected (see fig. 10).

The first cover 56 has a common ink chamber 62 that is open on a face facing the-Y direction (hereinafter, referred to as "front face"), and a plurality of slits 63 that are open on a face facing the + Y direction (hereinafter, referred to as "rear face").

The common ink chamber 62 is formed at a position corresponding to the + Z direction end of the ejection channel 57 in the Z direction. The common ink chamber 62 is recessed from the surface of the first cover 56 toward the + Y direction, and is provided extending in the X direction. The ink flows into the common ink chamber 62 through the first flow path member 51A described above.

The slit 63 is formed in the common ink chamber 62 at a position facing the discharge channel 57 in the Y direction. The slits 63 communicate the inside of the common ink chamber 62 with the inside of each discharge passage 57 individually. Therefore, the non-ejection channels 58 do not communicate with the inside of the common ink chamber 62.

In a portion of the first cover plate 56 that is located further outside in the X direction than the common ink chamber 62, a pair of first bubble discharge holes 65A are formed. Each of the first bubble discharge holes 65A extends between the first cover plate 56 and the first actuator plate 55 in the-Z direction after penetrating the first cover plate 56 in the Y direction. That is, in the first bubble removing hole 65A, the first opening portion opens on the surface of the first cover 56, and the second opening portion opens on the-Z direction end face of the first header chip 52A.

The second head chip 52B is configured by overlapping the second actuator plate 71 and the second cover plate 72 in the Y direction. In the following description, the same reference numerals as those of the first head chip 52A are attached to the second head chip 52B in the same configuration as the first head chip 52A, and the description thereof is omitted.

The second actuator plate 71 is joined to a surface (hereinafter referred to as "back surface") of the first actuator plate 55 facing the + Y direction. The ejection channels 57 and the non-ejection channels 58 of the second head chip 52B are arranged with a half pitch offset from the arrangement pitch of the ejection channels 57 and the non-ejection channels 58 of the first head chip 52A. That is, the discharge channels 57 and the non-discharge channels 58 of the head chips 52A and 52B are arranged in a staggered manner.

The second cover plate 72 is joined to a surface (hereinafter referred to as "surface") facing the + Y direction in the second actuator plate 71. In a portion of the second cover plate 72 located at least in the + X direction more than the common ink chamber 62, a second bubble discharge hole 65B is formed. The second bubble discharge hole 65B extends between the second cover plate 72 and the second actuator plate 71 in the-Z direction after penetrating the second cover plate 72 in the Y direction.

In the discharge portion 50, a region in which the channels 57 and 58 are arranged is referred to as a discharge region Q1, and regions located on both sides in the X direction with respect to the discharge region Q1 (regions located outside the outermost channels 57 and 58) are referred to as a pair of non-discharge regions Q2. In the non-discharge region Q2, communication holes 73 (only one communication hole 73 is shown in fig. 6 and 7) are formed to penetrate the discharge portion 50 (each head chip 52A and 52B) in the Y direction. The communication hole 73 penetrates the head chips 52A,52B (the actuator plates 55,71 and the cover plates 56,72) in the Y direction, and communicates the common ink chambers 62 of the head chips 52A,52B with each other. The number, position, shape, and the like of the communication holes 73 can be changed as appropriate.

(first flow path Member)

Fig. 8 is an exploded perspective view of the first channel member 51A, which is developed in the + Y direction from the first channel plate 77.

As shown in fig. 8, the first flow path member 51A has a first manifold 75 and an inflow port 76. Further, the first manifold 75 and the inflow port 76 may also be integrally formed.

The first manifold 75 is formed in a plate shape having the Y direction as a whole. As shown in fig. 3, the first manifold 75 is held by the base member 38 in a state of rising in the + Z direction by inserting the-Z direction end portion into the first module housing portion 44A.

As shown in fig. 8, the first manifold 75 includes a first channel member 77, a front cover 78 disposed in the + Y direction with respect to the first channel plate 77, and a rear cover 79 disposed in the-Y direction with respect to the first channel plate 77.

The first channel plate 77 is formed of a material having excellent thermal conductivity. In the present embodiment, a metal material (for example, aluminum or the like) is preferably used as the material of the first flow plate 77. The first ink flow path 81 through which ink flows toward the first head chip 52A is formed in the first flow path plate 77.

Fig. 9 is a front view of the first flow path plate 77 viewed from the + Y direction.

As shown in fig. 8 and 9, the first ink flow path 81 is formed by connecting an upstream flow path 83, a filter flow path 84, a downstream flow path 85, and a supply flow path 86 (see fig. 11).

The upstream channel 83 is opened in the + Y direction in the first channel plate 77. Specifically, the upstream flow path 83 includes a narrow flow path 91 and a connection flow path 92 connecting the narrow flow path 91 and the filtration flow path 84.

The narrow flow path 91 has a portion located in the + X direction and the + Z direction in the first flow path plate 77 as an upstream end, and has a portion located in the center in the Z direction and the X direction in the first flow path plate 77 as a downstream end, and is bent and extended from the upstream end to the downstream end. Specifically, the narrow-width flow path 91, after extending in the-Z direction from the upstream end, further extends in the-Z direction as extending in the-X direction toward the-Z direction. In the present embodiment, the flow channel width (width in the direction orthogonal to the flow direction and the Y direction) and the flow channel depth (depth in the Y direction) of the narrow flow channel 91 are set uniformly over the entire surface. However, the shape, flow channel width, and flow channel depth of the narrow flow channel 91 can be changed as appropriate.

As shown in fig. 9, the connection channel 92 is formed in a triangular shape in which the channel width gradually increases as the channel goes to the-Z direction in a front view seen from the + Y direction. The connection flow path 92 communicates with the downstream end of the narrow flow path 91 at the + Z direction end. In the present embodiment, the flow path width at the upstream end (+ Z direction end) of the connection flow path 92 is equal to the flow path width at the downstream end of the narrow flow path 91.

Fig. 10 is a cross-sectional view of the first injection module 30A corresponding to the X-X line of fig. 8.

As shown in fig. 10, the connecting channel 92 has a channel depth that becomes gradually shallower as it goes to the-Z direction in a front view seen from the + X direction. That is, the connection channel 92 of the present embodiment has a wider channel width from the upstream side to the downstream side, and a shallower channel depth from the upstream side to the downstream side. In the present embodiment, the depth of the flow path at the upstream end of the connecting flow path 92 is equal to the depth of the flow path at the downstream end of the narrow flow path 91.

The flow path sectional area (sectional area in XY plane) at the downstream end (-Z direction end) in the connection flow path 92 is preferably made smaller than the flow path sectional area at the upstream end. However, the flow path width, flow path depth, and flow path cross-sectional area of the connecting flow path 92 can be changed as appropriate.

In the present embodiment, a configuration in which the channel width and the channel depth change continuously (linearly) has been described, but the present invention is not limited to this configuration. That is, the connection channel 92 may be formed in a step shape or a curved shape, for example, as long as the channel width and the channel depth gradually change toward the downstream side. Further, a plurality of straight lines having different inclinations may be connected.

Fig. 11 is an enlarged view of a portion XI of fig. 10.

As shown in fig. 9 and 11, the filter flow path 84 communicates with the downstream end of the connection flow path 92 in the Z direction, and allows ink flowing from the connection flow path 92 to flow in the-Y direction. Specifically, the filtration flow path 84 has a filter inlet flow path 95 located in the + Y direction and a filter outlet flow path 96 connected in the-Y direction with respect to the filter inlet flow path 95.

The filter inlet channel 95 communicates with the connection channel 92 at the + Z direction end (upper end in the direction of gravity). The width in the X direction of the filter inlet channel 95 is equal to the width in the X direction of the downstream end of the connection channel 92.

The area (flow path cross-sectional area) of the filter outlet flow path 96 in a front view viewed in the Y direction is smaller than the filter inlet flow path 95. That is, a step surface 97 facing the + Y direction is formed at the boundary between the filter inlet channel 95 and the filter outlet channel 96. The stepped surface 97 is formed in a frame shape extending along the outer periphery of the filter inlet flow path 95.

In the filter inlet channel 95, a main filter 99 is disposed to partition the filter channel 84 in the Y direction into a filter inlet channel 95 and a filter outlet channel 96. The main filter 99 is a mesh sheet having an outer shape in plan view in the Y direction formed to have a size equal to that of the filter inlet channel 95. The outer peripheral portion of the main filter 99 is joined to the stepped surface 97 from the + Y direction. The ink passes through the main filter 99 while flowing from the filter inlet channel 95 to the filter outlet channel 96. Thereby, foreign matter and air bubbles contained in the ink are captured by the main filter 99.

As shown in fig. 11, a retention wall portion 100 that partitions the filter outlet flow path 96 and the downstream flow path 85 in the Y direction is formed on the inner surface of the filter outlet flow path 96. The retention wall portion 100 is provided upright in the + Z direction from the inside surface in the-Z direction (lower side in the gravity direction) in the inner surface of the filter outlet flow passage 96, and is formed over the entire filter outlet flow passage 96 in the X direction.

At the + Z direction end portion of the storage wall portion 100, a communication flow path 102 penetrating the storage wall portion 100 in the Y direction is formed. The communication flow path 102 is formed continuously over the entire retention wall portion 100 (filter outlet flow path 96) in the X direction. In the present embodiment, the + Z direction inner surface of the integrated passage 102 located in the + Z direction is flush with the + Z direction inner surface of the filter outlet passage 96 located in the + Z direction. That is, the communication passage 102 opens at the uppermost end portion of the filter outlet passage 96. However, the + Z direction inner surfaces of the communication flow passage 102 and the filter outlet flow passage 96 are not limited to be flush with each other.

The flow path sectional area (area in the XZ plane) at the upstream end of the communication flow path 102 is preferably smaller than the minimum flow path sectional area (sectional area in the XZ plane) of the above-described filter inlet flow path 95. However, the cross-sectional flow area of the communication flow path 102 may be equal to or larger than the minimum cross-sectional flow area of the filter inlet flow path 95. In the present embodiment, the description has been given of the case where the minimum flow path cross-sectional area of the filter inlet flow path 95 is set to the upstream end of the filter inlet flow path 95 (the boundary portion with the connection flow path 92), but the present invention is not limited to this configuration. That is, the minimum flow path cross-sectional area of the filter inlet flow path 95 can be set to any position of the filter inlet flow path 95.

Fig. 12 is an exploded perspective view of the first channel member 51A, developed in the-Y direction from the first channel plate 77.

As shown in fig. 10 and 12, the downstream flow path 85 is opened in the-Y direction in the first flow path plate 77. Specifically, the downstream flow path 85 has a straight portion 110, and an enlarged portion 111 connected to a downstream side of the straight portion 110.

The linear portion 110 faces the filter outlet flow path 96 in the Y direction, and sandwiches the retention wall portion 100 therebetween. The linear portion 110 has a channel width in the X direction equal to that of the filter outlet channel 96, and a channel depth in the Y direction is uniformly formed over the entire Z direction. The straight line path 110 communicates with the filter outlet flow path 96 through the communication flow path 102 at the + Z direction end portion. The flow path width and the flow path depth of the straight line 110 can be appropriately changed.

The enlarged portion 111 extends in the-Z direction from the-Z direction end of the linear portion 110. The expanded portion 111 has a channel width in the X direction equal to that of the expanded portion 110. The flow path depth of the enlarged portion 111 in the Y direction gradually becomes deeper toward the-Z direction. That is, the flow path cross-sectional area (cross-sectional area in the direction orthogonal to the Z direction) of the expanded portion 111 gradually expands toward the downstream side (-Z direction).

The supply channel 86 penetrates the first channel plate 77 in the Y direction at the-Z direction end of the first channel plate 77. The flow path width in the X direction in the supply flow path 86 is wider than that of the enlarged portion 111. In the present embodiment, the flow path width of the supply flow path 86 is set to be equal to that of the common ink chamber 62.

The upstream end (-Y direction end) of the supply flow path 86 communicates with the downstream end (-Z direction end) of the enlarged portion 111. On the other hand, the downstream end of the supply channel 86 opens in the + Y direction in the first channel plate 77.

As shown in fig. 9, the first bubble discharge flow path 120 communicating with the first ink flow path 81 is formed in the first flow path plate 77. The first bubble discharge flow path 120 is formed in a pair on both sides in the X direction with respect to the filter flow path 84. That is, the first bubble discharge flow path 120 is formed line-symmetrically with respect to a symmetry axis extending in the Z direction through the center in the X direction in the first flow path member 51A. Therefore, in the following description, the first bubble discharge channel 120 located in the + X direction with respect to the first ink channel 81 will be described. Further, the first bubble discharge flow paths 120 are not limited to a pair.

As shown in fig. 9 and 12, the first bubble discharge channel 120 includes a guide portion 121, a first through portion 122, a discharge portion 123, and a second through portion 124.

The guide portion 121 is opened in the + Y direction in the first channel plate 77. The guide passage 12 is connected to the connection passage 92 and the filter inlet passage 95 in the + X direction. Specifically, the guide portion 121 is formed in a tapered shape in which the width in the Z direction gradually decreases as going to the + X direction. Specifically, the + Z direction inner side surface located in the + Z direction among the inner surfaces of the guide portion 121 linearly extends in the X direction. However, the + Z direction inner side surface may extend obliquely in the + Z direction and the-Z direction as going to the + X direction.

An inner surface of the guide portion 121 in the-Z direction located in the-Z direction is formed as an inclined surface extending in the + Z direction as going to the + X direction. Further, the depth in the Y direction in the guide part 121 is uniform throughout the guide part 121. However, the depth of the guide portion 121 may also be gradually shallower, for example, as going to the + X direction.

The first through-hole 122 communicates with the guide portion 121 at the top of the guide portion 121 (the intersection of the inner surface in the + Z direction and the inner surface in the-Z direction). The first through portion 122 penetrates the first channel plate 77 in the Y direction. In the present embodiment, the first through portion 122 is disposed in the + Z direction and the X direction of the filter flow path 84. Further, the first through portion 122 is preferably disposed either in the + Z direction with respect to the filtration flow path 84 or in the + X direction with respect to the filtration flow path 84. However, the first through portion 122 is located in the Z direction and the X direction. However, the position of the first through portion 122 in the Z direction and the X direction can be changed as appropriate.

As shown in fig. 12, the discharge portion 123 is opened in the-Y direction in the first flow path plate 77. The discharge portion 123 extends in the Z direction. The + Z direction end of the discharge portion 123 communicates with the first through portion 122.

The second through portion 124 communicates with the-Z direction end of the discharge portion 123. The second through portion 124 penetrates the first channel plate 77 in the Y direction. A sub filter 126 is disposed at a boundary portion between the second through portion 124 and the discharge portion 123.

The rear cover 79 has an outer shape equivalent to the first flow passage plate 77 in a front view seen from the Y direction, and is formed in a rectangular plate shape having a thickness in the Y direction thinner than the first flow passage plate 77. The rear cover 79 is fixed to the surface of the first channel plate 77 facing the-Y direction. That is, the rear cover 79 closes the first ink flow path 81 (the downstream flow path 85 and the supply flow path 86) and the first bubble discharge flow path 120 (the through portions 122,124 and the discharge portion 123) from the-Y direction. In the present embodiment, the rear cover 79 is formed of a metal material (e.g., stainless steel) having excellent thermal conductivity.

Heater 130 is disposed on a surface of rear cover 79 facing the-Y direction. The heater 130 heats the inside of the first ink flow path 81 through the back cover 79, and thereby maintains (keeps) the ink flowing through the first ink flow path 81 within a predetermined temperature range.

As shown in fig. 8, the front cover 78 is a rectangular plate-like member having the same shape and size as the rear cover 79. That is, the thickness of the front cover 78 in the Y direction is thinner than the first flow plate 77. The front cover 78 is fixed to the surface of the first flow path plate 77 facing the + Y direction. That is, the front cover 78 closes the first ink flow path 81 (the upstream flow path 83 and the filter flow path 84) and the first bubble discharge flow path 120 (the guide portion 121 and the penetration portion 122) from the + Y direction.

A communication port 132 for opening the supply flow path 86 is formed in the front cover 78 at a position overlapping the supply flow path 86 when viewed in the Y direction. The communication port 132 has the same shape as the supply flow path 86 in a front view viewed in the Y direction, and penetrates the front cover 78 in the Y direction.

An inlet 133 for opening the upstream flow path 83 is formed in the front cover 78 at a position overlapping the upstream end (+ Z-direction end) of the upstream flow path 83 when viewed in the Y direction. The inflow port 133 penetrates the front cover 78 in the Y direction.

A discharge port 134 for opening the second through-hole 124 is formed in the front cover 78 at a position overlapping the second through-hole 124 when viewed in the Y direction. The discharge port 134 penetrates the front cover 78 in the Y direction.

In the present embodiment, the case where the groove-shaped first ink flow path 81 is formed only in the first flow path member 77 has been described, but the present invention is not limited to this configuration, and the first flow path member 77 may be formed with an ink flow path in at least one of the front cover 78 and the rear cover 79. In this case, for example, grooves may be formed in the first channel plate 72, the front cover 78, and the rear cover 79, respectively, and the ink channels may be formed by overlapping these grooves.

The inflow port 76 is formed in a cylindrical shape extending in the Z direction. The inflow port 76 is fixed to the + Z direction end in the front cover 78. The inflow port 76 communicates with the first ink flow path 81 through the inflow port 133.

(first insulating sheet)

As shown in fig. 8, a first insulating sheet 135 is provided on the surface of the front cover 78 facing the + Y direction. The first insulating sheet 135 is formed in a U shape opened in the-Z direction in a front view seen from the Y direction. The first insulating sheet 135 surrounds the periphery of the communication port 132 in the front cover 78. Specifically, the first insulating sheet 135 has a pair of outer side pedestal portions 136 located on both sides in the X direction with respect to the communication port 132, and a bridge portion 137 connecting the + Z direction end portions of the outer side pedestal portions 136 to each other. Further, in the present embodiment, polyimide is preferably used for the first insulating sheet 135, for example. However, the material of the first insulating sheet 135 can be appropriately changed if it is formed of a relatively soft material (e.g., a resin material or a rubber material) having insulation properties and ink resistance (elution resistance).

In the outer pedestal 136, an exposure port 140 for exposing the discharge port 134 is formed at a position overlapping the discharge port 134 as viewed in the Y direction. The exposure port 140 penetrates the outer stage 136 in the Y direction.

In the outer stage 136, a positioning hole 142 that penetrates the outer stage 136 in the Y direction is formed in a portion located in the + Z direction with respect to the exposure port 140. The positioning hole 142 accommodates an engagement pin 143 protruding from the first channel member 51A in the + Y direction. In addition, positioning holes 142 may also be formed in the bridge portion 137.

The bridge 137 is located in the + Z direction with respect to the communication port 132. That is, in the front cover 78, a portion located in the-Z direction with respect to the communication port 132 is a blank region 141 where the first insulating sheet 135 is not located. The first insulating sheet 135 may have only the outer mount 136 in at least the non-discharge region Q2.

As shown in fig. 10, the first header chip 52A is fixed to the front cover 78 and the first insulating sheet 135 with the surface of the first cover 56 facing the Y direction. Specifically, of the surface of the first lid 56, a portion facing the first insulating sheet 135 is fixed to the first insulating sheet 135 via an adhesive S1. On the other hand, of the surface of the first cover 56, the portion facing the blank area 141 is directly fixed to the front cover 78 via the adhesive S1.

In a state where the first head chip 52A is fixed to the first flow path member 51A, the driving wall 61 (the discharge area Q1 shown in fig. 6) and the blank area 141 face each other in the Y direction. That is, in the present embodiment, only the adhesive S1 is interposed (the first insulating sheet 135 is not interposed) between the driving wall 61 and the front cover 78. In this case, the adhesive S1 surrounds the common ink chamber 62 and the communication port 132, and seals the space between the first head chip 52A and the first channel member 51A. The adhesive S1 used in the present embodiment is made of a material (for example, silicon-based) that has insulating properties and is relatively soft (softer than the first insulating sheet 135).

In a state where the first head chip 52A is fixed to the first flow path member 51A, the common ink chamber 62 of the first cover 56 communicates with the supply flow path 86 through the communication port 132. On the other hand, as shown in fig. 8, the first bubble discharge hole 65A (see fig. 7) of the first header chip 52A communicates with the first bubble discharge passage 120 (the second penetration portion 124) through the exposure port 140 and the discharge port 134.

(second flow path Member)

As shown in fig. 5, the second channel member 51B includes a second manifold 150 and a second biasing member 151.

The second manifold 150 is formed in a plate shape having the Y direction as a whole, and the Z direction length shorter than the first manifold 75. As shown in fig. 3, the second manifold 150 is held by the base member 38 in a state of rising in the + Z direction by inserting the-Z direction end portion into the first module housing portion 44A.

As shown in fig. 5, the second manifold 150 has a second flow path plate 152 and a flow path cover 153.

The second flow passage plate 152 is formed of a metal material (e.g., aluminum) or the like, as in the case of the first flow passage plate 77. The second ink flow path 155 through which ink flows toward the second head chip 52B is formed in the second flow path plate 152.

Fig. 13 is a front view of the second flow plate 152 viewed from the + Y direction.

As shown in fig. 13, the second ink flow path 155 penetrates the second flow path plate 152 in the Y direction, and extends in a band shape in the X direction. The second ink flow path 155 has a front view shape as viewed in the Y direction, which is formed in a shape equivalent to the common ink chamber 62. Therefore, the communication hole 73 of the ejection unit 50 faces the second ink flow path 155 in the Y direction at both ends of the second ink flow path 155 in the X direction. In the present embodiment, it is preferable that the total volume of the second ink flow path 155 and the common ink chamber 62 of the second head chip 52B is set to be equal to the total volume of the supply flow path 86 and the common ink chamber 62 of the first head chip 52A.

Reference numeral 157 in fig. 13 denotes a purge flow path communicating with the second ink flow path 155. The cleaning liquid sucked up from a nozzle hole 240 described later and passing through the discharge portion 50 and the second ink flow path 155 flows into the cleaning flow path 157 at the time of maintenance or the like. The cleaning liquid flowing into the cleaning flow path 157 is sucked through the cleaning port 158.

In the second channel plate 152, a second bubble discharge channel 160 communicating with the second ink channel 155 is formed. The second bubble discharge channel 160 includes a discharge portion 161 and a penetration portion 162.

The discharge portion 161 opens in the + Y direction in the second flow plate 152. The discharge portion 161 extends in the X direction with respect to the portion of the second ink flow path 155 located in the + Z direction in the second flow path plate 152. The upstream end of the discharge portion 161 is open at the center in the X direction, among the + Z direction inner surfaces located in the + Z direction (upward in the gravity direction) of the inner surfaces of the second ink flow path 155. That is, the distances in the X direction between the pair of communication holes 73 and the upstream end of the discharge portion 161 are set to be equal to each other. Further, the distance between the pair of communication holes 73 and the upstream end of the discharge portion 161 in the X direction can be changed as appropriate. The number and position of the communication holes 73 can be changed as appropriate.

The downstream end of the discharge portion 161 communicates with the through portion 162 at a portion located in the + X direction with respect to the second ink flow path 155. In the present embodiment, the configuration in which the second bubble discharge flow path 160 is arranged in the + Z direction with respect to the second ink flow path 155 has been described, but the configuration is not limited to this configuration.

The through portion 162 penetrates the second flow passage 152 in the Y direction. In the through portion 162, a sub filter 165 is disposed.

In the second flow path plate 152, the sensor housing section 167 is formed in the portion of the second bubble discharge flow path 160 located in the + Z direction. The sensor accommodation portion 167 is opened in the + Y direction in the second flow plate 152, and extends in the X direction.

As shown in fig. 5, the flow path cover 153 has an outer shape equivalent to that of the second flow path plate 152 in a front view seen from the Y direction, and is formed in a rectangular plate shape having a thickness in the Y direction thinner than the second flow path plate 152. The flow path cover 153 closes the second ink flow path 155, the second bubble discharge flow path 160, and the sensor housing section 167 from the + Y direction. The flow path cover 153 is formed of a metal material (e.g., stainless steel) having excellent thermal conductivity.

The second biasing members 151 are provided in a pair at both ends of the second flow passage plate 152 in the X direction. Each second biasing member 151 is a leaf spring whose free end is disposed in the + Y direction with respect to the second channel plate 152. As shown in fig. 3, in a state where the second flow path member 51B is inserted into the first module housing portion 44A, the second acting member 151 is interposed between the first long side portion 45c and the second manifold 150 among the long side portions 45c,45d opposed to each other in the Y direction in the base main body portion 41. That is, the second operating member 151 operates the injection module 30A in the-Y direction. That is, the second biasing member 151 biases the injection module 30A in the-Y direction.

(second insulating sheet)

As shown in fig. 5, a second insulating sheet 170 is provided on a surface facing the-Y direction in the second flow plate 152. The second insulating sheet 170 includes an outer pedestal portion 171 and a bridge portion 172, similarly to the first insulating sheet 135 described above.

In each of the outer base sections 171, an exposure opening 175 through which the through-section 162 is exposed is formed in the outer base section 171 located in the + X direction at a position overlapping the through-section 162 when viewed in the Y direction. The exposure port 175 penetrates the outer stage 171 in the Y direction.

The bridge 172 is located in the + Z direction with respect to the second ink flow path 155. That is, in the second channel plate 152, the portion located in the-Z direction with respect to the second ink channel 155 is a blank region 178 where the second insulating sheet 135 is not located (see fig. 10).

In the bridge portion 172, positioning holes 173 penetrating the bridge portion 172 in the Y direction are formed at both ends in the X direction. The positioning hole 173 accommodates an engagement pin (not shown) protruding from the second channel member 51B in the-Y direction. In addition, a positioning hole 173 may be formed in the outer base 171.

As shown in fig. 10, the second head chip 52A is fixed to the second flow path plate 152 and the second insulating sheet 170 with the surface of the second cover plate 72 facing in the + Y direction. Specifically, a portion of the surface of the second cover plate 72 facing the second insulating sheet 170 is fixed to the second insulating sheet 170 via the adhesive S2. On the other hand, of the surface of the second cover 72, the portion facing the blank region 178 is directly fixed to the second flow passage plate 152 via the adhesive S2. In a state where the second head chip 52B is fixed to the second flow path member 51B, the driving wall 61 (the discharge region Q1 shown in fig. 6) and the blank region 178 face each other in the Y direction. In this case, the adhesive S2 surrounds the common ink chamber 62 and the second ink flow path 155, and seals the space between the second head chip 52B and the second flow path member 51B. The same materials are used for the adhesives S1 and S2.

In the present embodiment, the structure in which the insulating sheet 135,170 is interposed between the head chips 52A,52B has been described, but at least the first insulating sheet 135 may be interposed between the first head chip 52A and the first channel member 51A.

In a state where the second head chip 52B is fixed to the second flow path member 51B, the common ink chamber 62 of the second cover 72 communicates with the second ink flow path 155. The second bubble discharge hole 65B of the second head chip 52B communicates with the second bubble discharge channel 160 (through portion 162) through the exposure port 175.

In this way, in the injection module 30A of the present embodiment, the first channel member 51A and the second channel member 51B face each other in the Y direction, and the discharge portion 50 having the two head chips 52A,52B is sandwiched between the channel members 51A, 51B.

(FPC Unit)

As shown in fig. 5, the FPC unit 180 is supported in the front cover 78 of the first manifold 75. The FPC unit 180 includes a driving substrate 181 and a wiring substrate 182. The drive substrate 181 and the wiring substrate 182 are each a flexible printed circuit board, and are configured by forming a wiring pattern on an underlying film.

Drive substrate 181 includes mounting portion 185, chip connection portion 186, sensor connection portion 187, and lead portion 188. In addition, the driving board 181 may use a rigid board or the like in the mounting portion 185.

The fitting portion 185 is supported by the front cover 78. For example, a plurality of drivers 190A,190B are mounted to the mounting portion 185. The drivers 190A,190B are a first driver 190A that drives the first head chip 52A and a second driver 190B that drives the second head chip 52B. The drivers 190A and 190B are arranged linearly in the X direction. In the present embodiment, the configuration in which the first driver 190A and the second driver 190B are mounted on one drive substrate 181 is described, but the present invention is not limited to this configuration, and a drive substrate may be provided for each driver.

As shown in fig. 10, the chip connection portions 186 are provided extending from the mounting portion 185 in the-Z direction. the-Z direction end of the chip connection portion 186 is fixed to the + Z direction end of the first actuator plate 55 by crimping or the like. Thereby, the first driver 190A and the driving electrode 59 of the first head chip 52A are electrically connected via the chip connection portion 186.

As shown in fig. 5 and 13, the sensor connecting portion 187 extends from the fitting portion 185 in the + X direction. At the front end of the sensor connecting portion 187, a temperature sensor 191 (e.g., a thermistor or the like) is mounted. The sensor connecting portion 187 is accommodated in the sensor accommodating portion 167 described above. That is, the temperature sensor 191 detects the ink temperature of the ejection portion 50 via the second channel plate 152.

The lead portion 188 extends from the mounting portion 185 in the + Z direction. The lead portion 188 is connected to the interface 192 (see fig. 3). The interface 192 is used to supply power to the FPC unit 180 from, for example, power supplied from the outside of the inkjet head 5A, or to transmit and receive control signals.

As shown in fig. 5 and 10, the wiring substrate 182 connects the mounting portion 185 and the second head chip 52B. Specifically, the + Z direction end of the wiring board 182 is connected to the mounting portion 185, and the-Z direction end is fixed to the + Z direction end of the second actuator plate 71 by crimping or the like. Thereby, the second driver 190B and the driving electrode 59 of the second head chip 52B are electrically connected via the wiring substrate 182.

As shown in fig. 3 and 5, a heat sink 195 is disposed in the first channel member 51A at a position where the drivers 190A and 190B overlap each other when viewed from the Y direction. The heat dissipation plate 195 is formed to extend across the drive substrate 181 in the X direction. The heat dissipation plate 195 covers the drivers 190A,190B with the heat transfer sheet 196 interposed therebetween. Both ends of the heat sink 195 in the X direction are fixed to the first channel member 51A outside the drive substrate 181. The heat sink 195 and the heat transfer sheet 196 are made of a material having excellent thermal conductivity. In the present embodiment, the heat dissipation plate 195 is formed of, for example, aluminum, and the heat transfer sheet 196 is formed of, for example, silicone.

As shown in fig. 3 and 4, the first injection module 30A is inserted into the first module housing portion 44A with the first channel member 51A facing in the-Y direction and the second channel member 52B facing in the + Y direction. At this time, the first injection module 30A is held by the base member 38 with the first biasing member 48 interposed between the second channel member 51B and the first short side 45a and the second biasing member 151 interposed between the second channel member 51B and the first long side 45 c. Therefore, the first injection module 30A is held by the base member 38 while being biased in the-X direction (the direction toward the second short side portion 45 b) by the first biasing member 48 and in the-Y direction (the direction toward the partition portion 46) by the second biasing member 151. At this time, the-Z direction end face of the discharge portion 50 is preferably disposed flush with the-Z direction end face of the base member 38 (base main body portion 41), or is preferably disposed in the-Z direction further than the (Z direction end face of the base member 38).

The second injection module 30B is inserted into the second module housing portion 44B with the first channel member 51A facing in the + Y direction and the second channel member 52B facing in the-Y direction. That is, the first channel member 51A of the second injection module 30B and the first channel member 51A of the first injection module 30A face each other in the Y direction. Each injection module 30A,30B is fixed to the corresponding module housing portion 44A,44B by an adhesive.

(pillar unit)

As shown in fig. 2, the base member 38 is provided with a column unit 200 that supports the mounting member on the base member 38. The pillar unit 200 stands up from the base member 38 in the + Z direction, and surrounds the periphery of each of the injection modules 30A,30B together.

The module holding mechanism 210 is interposed between the X-direction support (the first support 201 and the second support 202) located on both sides in the X direction among the support units 200 and the injection modules 30A, 30B. Note that, since each of the module holding mechanisms 210 has the same configuration, the module holding mechanism 210 interposed between the first pillar 201 and the first injection module 30A will be described as an example in the following description.

The first support column 201 is located in the + X direction with respect to the injection module portions 30A, 30B. The first support column 201 stands up from the base member 38 in the + Z direction with the-Z direction end inserted into the module accommodating portions 44A,44B with the manifold 52 inserted therein. The first support column 201 is assembled to the base member 38 after the injection module units 30A and 30B are assembled to the base member 38.

Fig. 14 is a sectional view taken along the line XIV-XIV of fig. 2.

As shown in fig. 3 and 14, the module holding mechanism 210 includes a positioning pin 212 provided in the first flow path member 51A, a first housing portion 214 formed in the first support column 201, and a support piece 216 for coupling the positioning pin 212 and the first support column 201.

The positioning pin 212 protrudes from the first flow path member 77 in the + X direction. Further, it is preferable that the positioning pins 212 are disposed at positions spaced apart from the base member 38 in the Z direction. In the present embodiment, the positioning pin 212 is disposed in a portion of the first flow passage plate 77 located in the + Z direction from the center portion in the Z direction.

The first receiving portion 214 is formed to penetrate through a portion overlapping with the positioning pin 212 in the X direction in a side view seen from the X direction in the first pillar 201. The first accommodation portion 214 is formed circularly in a side view seen from the X direction, and the inner diameter is formed similarly. The inner diameter of the first receiving portion 214 is larger than the outer diameter of the positioning pin 212. The positioning pin 212 described above penetrates the first accommodating portion 214 and protrudes in the + X direction with respect to the first pillar 201.

The support piece 216 is plate-shaped with the Z direction as the longer direction. The support piece 216 is fixed to the first pillar 201 so as to close the first housing portion 214 from the + X direction. Specifically, in the support piece 216, a second housing portion 220 penetrating the support piece 216 in the X direction is formed at a position where the first housing portions 214 overlap in a side view seen from the X direction. The second accommodation portion 220 is formed circularly in a side view seen from the X direction, and the inner diameter is formed similarly. The inner diameter of second receiving portion 220 is smaller than the inner diameter of first receiving portion 214 and larger than the outer diameter of positioning pin 212. The positioning pin 212 described above is inserted into the second receiving portion 220. Further, the outer peripheral surface of the positioning pin 212 contacts the inner peripheral surface of the second housing portion 220, thereby restricting the movement of the first injection module 30A with respect to the first support 201 in the direction orthogonal to the X direction.

In addition, the positioning pin 212 may be fitted in the second accommodation portion 220. The first and second accommodation portions 214 and 220 may have a rectangular or triangular shape, as well as a circular shape in a side view. The first housing portion 214 and the second housing portion 220 may have different shapes. Even in such a case, the opening area of the second housing portion 220 is set smaller than the opening area of the first housing portion 214.

The second receiving portion 220 may not penetrate the support piece 216 if a positioning pin can be inserted.

The first and second receiving portions 214 and 220 may have gradually changing inner diameters.

The support piece 216 is fixed to the first support column 201 by screws on both sides in the Z direction with respect to the second housing portion 220. Specifically, the support piece 216 has relief holes 223 formed on both sides in the Z direction with respect to the second housing portion 220. The inside diameter of the relief hole 223 is larger than the outside diameter of the screw 222. The screw 222 is fastened to the first pillar 201 through the relief hole 223. The support piece 216 is sandwiched between the head of the screw 222 and the first pillar 201 in the X direction, and the support piece 216 is fixed to the first pillar 201. Further, the tip of the screw 222 approaches the first flow passage plate 77 in the X direction.

In this way, the first injection module 30A of the present embodiment is held by the base member 38 by inserting the-Z direction end into the first module housing portion 44A, and the + Z direction end is held by the module holding mechanism 210.

(damper)

As shown in fig. 2, the dampers 31 are provided in the + Z direction with respect to the ejection modules 30A,30B, and are provided corresponding to the respective ejection modules 30A,30B (corresponding to the color of the ink). The dampers 31 are arranged in parallel in the Y direction. Each damper 31 has the same configuration except for the color of the ink to be supplied. Therefore, in the following description, one damper 31 (the damper 31 of the first injection module 30A) will be described, and the description of the other damper 31 will be omitted.

The damper 31 is fixed to the pillar unit 200 in the + Z direction with respect to the first injection module unit 30A. The damper 31 has an inlet port 230, a pressure buffer 231, and an outlet port 232. Further, the damper 31 may also be provided separately from the inkjet head 5A.

The inlet port 230 is formed in a cylindrical shape protruding in the + Z direction from the pressure buffer 231. The ink pipe 16 (see fig. 1) is connected to the inlet port 230. The ink in the ink tank 15 flows into the inlet port 230 through the ink pipe 16.

The pressure buffer 231 is generally formed in a box shape. The pressure buffer 231 is configured by housing a movable film and the like therein. The pressure buffer 231 is disposed between the ink tank 15 (fig. 1) and the first ejection module 30A to absorb pressure fluctuations of the ink supplied to the damper 31 through the inlet port 230.

The outlet port 232 protrudes in the-Z direction from a position diagonal to the inlet port 230 in the pressure buffer 231. The ink discharged from the pressure buffer 231 flows into the outlet port 232. The inlet port 76 of the first ejection module 30A is connected to the outlet port 232.

The above-described interface 192 is disposed in a portion between the dampers 31 facing each other in the Y direction. The interface 192 is supported by the pillar unit 200.

(nozzle plate)

The nozzle plate 32 is made of a resin material such as polyimide. The nozzle plate 32 is fixed to the-Z-direction end surface of the base body portion 41 and the-Z-direction end surface of the ejection portion 50 (the portions exposed from the module housing portions 44A, 44B) via an adhesive. The nozzle plate 32 covers the ejection portions 50 of the ejection modules 30A and 30B from the-Z direction.

As shown in fig. 6 and 7, the nozzle hole 240 penetrating the nozzle plate 32 in the Z direction is formed in the nozzle plate 32. The nozzle holes 240 are formed at positions facing the discharge channels 57 of the head chips 52A,52B in the Z direction, respectively.

In the nozzle plate 32, discharge holes 241A,241B penetrating the nozzle plate 32 in the Z direction are formed at positions facing the above-described bubble discharge holes 65A,65B in the Z direction. That is, in the present embodiment, the nozzle holes 241 and the discharge holes 241A,241B are opened on the discharge surface (surface facing the-Z direction) of the nozzle plate 32. The discharge holes 241A,241B of the present embodiment are a first discharge hole 241A communicating with the first bubble discharge hole 65A and a second discharge hole 241B communicating with the second bubble discharge hole 65B. The inner diameter (opening area) of the second exhaust hole 241B is smaller than the inner diameter of the first exhaust hole 241A. However, the inner diameters of the discharge holes 241A and 241B can be changed as appropriate. The discharge holes 241A and 241B are not limited to circular holes.

The ink in the nozzle hole 240 and the discharge holes 241A and 241B forms an appropriate (concave) meniscus by surface tension or the like acting on the inner surfaces of the nozzle hole 240 and the discharge holes 241A and 241B. That is, in the printer 1 of the present embodiment, the pressure in the discharge channel 57 is maintained at a desired negative pressure by the head difference between the liquid surface of the ink tank 15 and the liquid surface of the meniscus. This retains the meniscus and prevents ink from leaking out accidentally.

The nozzle plate 32 is not limited to a resin material, and may be formed of a metal material (stainless steel or the like), or may have a laminated structure of a resin material and a metal material. In the present embodiment, the configuration in which the emission modules 30A and 30B are covered with one nozzle plate 32 is described, but the present invention is not limited to this configuration, and may be configured such that the emission modules 30A and 30B are individually covered with a plurality of nozzle plates 32.

(nozzle guard)

As shown in fig. 2, the nozzle guard 33 is formed by press working a plate material such as stainless steel. The nozzle guard 33 covers the substrate body portion 41 from the-Z direction with the nozzle plate 32 sandwiched therebetween.

Exposure holes 245 for exposing the nozzle rows 32 to the outside are formed in the nozzle guard 33 at positions facing the discharge portions 50 of the respective injection modules 30A,30B in the Z direction. The exposure hole 245 is formed in a slit shape that penetrates the nozzle guard 33 in the Z direction and extends in the X direction. The exposure holes 245 are formed in two rows at intervals in the Y direction corresponding to the respective injection modules 30A and 30B. The nozzle holes 240 and the discharge holes 241A and 241B are communicated with the outside of the inkjet head 5A through the exposure holes 245. Further, a cap may be attached to the nozzle guard 33 to be brought into close contact with the nozzle guard 33 from the-Z direction during filling of ink, stopping of printing operation, or the like, and to seal the nozzle hole 240 and the discharge holes 241A and 241B.

[ method of operating Printer ]

Next, a method of recording information on the recording medium P by the printer 1 will be described.

As shown in fig. 1, when the printer 1 is operated, the raster rollers 11 and 13 of the transport mechanisms 2 and 3 rotate, and the recording medium P is transported in the + X direction between the raster rollers 11 and 13 and the pinch rollers 12 and 14. Further, at the same time, the drive motor 28 rotates the pulley 26 to run the endless belt 27. Thereby, the carriage 23 reciprocates in the Y direction while being guided by the guide rails 21 and 22.

During this time, in each of the ink jet heads 5A and 5B, a driving voltage is applied to the driving electrodes 59 (see fig. 7) of the head chips 52A and 52B. This causes the thickness of the driving wall 61 to be slidably deformed, thereby generating a pressure wave in the ink filled in the discharge passage 57. The pressure wave increases the internal pressure of the discharge channel 57, and the ink is discharged through the nozzle hole 240. Then, various kinds of information are recorded on the recording medium P by the ink hitting on the recording medium P.

Here, the flow of ink in the first ejection block 30A of the inkjet head 5A will be described.

In the present embodiment, as shown in fig. 3, the ink supplied from the ink tank 15 to the inkjet head 5A passes through the damper 31 and then flows into the first manifold 75 of the ejection module 30A through the inflow port 76.

As shown by the solid arrows in fig. 10, the ink flowing into the first manifold 75 passes through the upstream flow path 83, and then flows into the filter inlet flow path 95 of the filter flow path 84 from the + Z direction. As shown by the solid arrows in fig. 11, the ink flowing into the filter inlet channel 95 passes through the main filter 99 while passing from the filter inlet channel 95 to the filter outlet channel 96. This causes foreign matter and bubbles contained in the ink to be trapped in the main filter 99. The flow of ink reaching the filter outlet channel 96 in the-Y direction (downstream channel 85) is blocked by the reservoir wall portion 100. Thereby, the filter outlet channel 96 is filled with ink.

When the ink filled in the filter outlet flow path 96 reaches the communication flow path 102, the ink flows into the downstream flow path 85 through the communication flow path 102. After the ink flows through the downstream flow path 85 in the-Z direction, the ink flows in the + Y direction through the supply flow path 86. The ink flowing in the supply flow path 86 flows into the common ink chamber 62 of the first head chip 52A through the communication port 132. Among the inks flowing into the common ink chamber 62 of the first head chip 52A, a part of the inks flows into the ejection channels 57 through the slits 63 in the first head chip 52A, and then is ejected through the nozzle holes 240.

On the other hand, among the inks flowing into the common ink chamber 62 of the first head chip 52A, a part of the inks flows into the communication hole 73 at both end portions in the X direction in the common ink chamber 62. Thereafter, the ink flows into the common ink chamber 62 of the second head chip 52B through the communication hole 73. The ink flowing into the common ink chamber 62 of the second head chip 52B flows inward in the X direction while filling the second ink flow path 155. Thereafter, the ink flowing into the second head chip 52B flows into the discharge channel 57 through the slit 63, and then is discharged through the nozzle hole 240.

However, as shown by the broken line arrows in fig. 9, in the first ink flow path 81, the air bubbles remaining in the filter inlet flow path 95 (on the upstream side with respect to the main filter 99) are discharged to the outside of the first ejection module 30A through the first air bubble discharge flow path 120. Specifically, the air bubbles trapped in the main filter 99 and the air bubbles accumulated in the filter inlet channel 95 are pushed out to both sides in the X direction in the process of the ink flowing to both sides in the X direction in the filter inlet channel 95. After that, the bubbles move in the + Z direction outside the X direction in the guide portion 121 after entering the guide portion 121. Then, the bubbles move in the-Y direction through the first through hole 122. Thereafter, the air bubbles move in the-Z direction through the discharge portion 123, and then pass through the sub-filter 126 (see fig. 12) and enter the second through portion 124. The air bubbles entering the second through portion 124 enter the first air bubble discharge hole 65A of the first head chip 52A as shown in fig. 6, and then are discharged to the outside through the first discharge hole 241A of the nozzle plate 32.

On the other hand, in the case where the air bubbles are accumulated in the common ink chamber 62 of the second head chip 52B and the second flow path member 51B (the second ink flow path 155), the air bubbles are discharged to the outside of the first ejection module 30A through the second air bubble discharge flow path 160. Specifically, the bubbles accumulated in the second ink flow path 155 and the like reach the through portion 162 through the discharge portion 161. The air bubbles that have reached the through portion 162 pass through the sub-filter 165, and then enter the second air bubble discharge hole 65B of the second head chip 52B as shown in fig. 6. After that, the air bubbles are discharged to the outside through the second discharge holes 241B of the nozzle plate 32.

As described above, in the present embodiment, the first bubble discharge passage 120 that communicates the inside and the outside of the first ink passage 81 is formed in the first passage member 51A, and the second bubble discharge passage 160 that communicates the inside and the outside of the second ink passage is formed in the second passage member 51A.

With this configuration, the air bubbles that have accumulated in the first ink flow path 81 and the second ink flow path 155 can be discharged through the first air bubble discharge flow path 120 and the second air bubble discharge flow path 160, respectively. Therefore, it is possible to suppress entry of air bubbles into the respective head chips 52A,52B, and improve the filling property of ink in the respective head chips 52A, 52B. This improves the discharge stability.

In the present embodiment, the nozzle hole 240 and the discharge holes 241A,241B are configured to open on the same surface (discharge surface) of the nozzle plate 32.

According to this configuration, for example, when the nozzle hole 240 and the discharge holes 241A and 241B are sealed by a cap at the time of filling ink or at the time of stopping a printing operation, the nozzle hole 240 and the discharge holes 241A and 241B can be covered by one cap. Therefore, the maintainability can be improved.

However, as described above, in the second ink flow path 155, a part of the ink in the first ink flow path 81 is supplied through the communication hole 73. In this case, the second ink flow path 155 is located on the downstream side of the first ink flow path 81, and therefore is likely to be higher in pressure than the pressure in the first ink flow path 81.

Thus, according to the present embodiment, the surface tension acting on the inner surface of the second exhaust hole 241B can be made higher than the surface tension acting on the inner surface of the first exhaust hole 241A by making the inner diameter of the second exhaust hole 241B smaller than the inner diameter of the first exhaust hole 241A. This makes it easy to stabilize the meniscus in the second discharge hole 241B, and prevents ink from leaking through the second discharge hole 241B.

Further, by stabilizing the meniscus in the second discharge hole 241B, it is possible to suppress, for example, the meniscus from being broken by the negative pressure generated in the second head chip 52B and the outside air (air) from entering the second head chip 52B through the second discharge hole 241B when the inkjet heads 5A,5B are used (when ink is discharged, etc.). Therefore, the air entering from the second discharge hole 241B is prevented from becoming bubbles and staying in the second head chip 52B, and the discharge stability can be improved.

In the present embodiment, the pair of communication holes 73 and the upstream end of the discharge portion 161 are equally spaced in the X direction.

With this configuration, while the ink flows through the second ink flow path 155 from the communication holes 73 to the center portion in the X direction, the air bubbles retained in the second ink flow path 155 can be uniformly pushed out toward the second air bubble discharge flow path 160 from both sides in the X direction. This can more reliably suppress the entry of air bubbles into the second head chip 52B.

In the present embodiment, the sub-filter 126,165 is disposed in each of the first bubble discharge flow path 120 and the second bubble discharge flow path 160.

According to this configuration, by increasing the flow path resistance in the bubble discharge flow paths 120 and 165 by the sub-filter 126,165, it is possible to suppress the meniscus in the second discharge hole 241B from being broken by pressure fluctuations in the second bubble discharge flow path 160 due to the flow of ink from the upstream, the discharge of ink from the nozzle holes 240, and the like. This makes it easy to stabilize the meniscus in the discharge holes 241A,241B, and prevents ink from leaking through the discharge holes 241A, 241B. In the present embodiment, the configuration in which the surface tension is adjusted by making the inner diameters of the discharge holes 241A and 241B different from each other has been described, but the present invention is not limited to this configuration, and the surface tension may be adjusted by making the flow path resistances of the sub filters 126,165 different from each other.

In the present embodiment, since the inkjet heads 5A and 5B are provided, the printer 1 having excellent discharge performance can be provided.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, in the above-described embodiment, the inkjet printer 1 is described as an example of the liquid ejecting apparatus, but the present invention is not limited to the printer. For example, it may also be a facsimile machine, an on-demand printer, etc.

In the above embodiment, the configuration in which the two injection modules 30A and 30B are mounted on the base member 38 has been described, but the present invention is not limited to this configuration. The number of the injection modules mounted on the base member 38 may be one or three or more.

Although the head chip for irradiation is described in the above embodiments, the present invention is not limited to this. For example, the present invention can be applied to a head chip of a so-called side shooter type (i.e., a side shooter type) that ejects ink from a central portion in an extending direction of an ejection channel.

The present invention can be applied to a head chip of a so-called top-shooter type (roof type) in which the direction of the pressure applied to the ink and the direction of discharge of the ink are the same.

In the above embodiment, the configuration in which the communication hole 73 is formed in each of the head chips 52A and 52B itself has been described, but the present invention is not limited to this configuration. A communication flow path for communicating the head chips 52A,52B may be provided separately from the head chips 52A, 52B.

In the above-described embodiment, the configuration in which the ink flow paths 81,155 communicate with each other through the communication hole 73 has been described, but the configuration is not limited to this configuration, and the inflow ports may be provided separately for the flow path members 51A,51B, and ink may be supplied separately from the flow path members 51A, 51B.

In the above embodiment, the configuration in which the Z direction coincides with the gravity direction has been described, but the present invention is not limited to this configuration, and the Z direction may coincide with the horizontal direction.

In the above-described embodiment, the configuration in which the discharge holes 241A,241B are formed in the nozzle plate 32 has been described, but the present invention is not limited to this configuration. In addition, discharge holes may be formed in the flow path members 51A,51B, the head chips 52A,52B, and the like.

In the above-described embodiment, the configuration in which the two head chips 52A,52B are mounted on one injection module has been described, but the present invention is not limited to this configuration. That is, one head chip may be mounted on one injection module.

In addition, the components in the above embodiments may be replaced with known components as appropriate without departing from the scope of the present invention, and the above modifications may be combined as appropriate.

Description of the symbols

1 ink jet printer (liquid jet device)

5A,5B ink jet head (liquid jet head)

15 ink storage tank (supply source)

32 nozzle plate (jet orifice plate)

51A first channel Member

51B second channel Member

52A first header chip

52B second head chip

57 discharge passage (first pressure changing chamber, second pressure changing chamber)

62 common ink chamber (liquid chamber)

71 second actuator plate

72 second cover plate

73 communication hole (communication flow path)

76 inflow port

81 first ink flow path (first liquid flow path)

120 first bubble discharge flow path

126,165 Secondary Filter

155 second ink flow path (second liquid flow path)

160 second bubble discharge channel

241A first discharge hole

241B second exhaust hole

Q1 spit region (ejection region).

Claims (6)

1. A liquid ejection head, comprising:

a first head chip and a second head chip which are stacked in a first direction and which eject a liquid;

a first channel member which is disposed on the opposite side of the first head chip from the second head chip in the first direction, and which has a first liquid channel communicating with the first head chip; and

a second channel member which is disposed on the opposite side of the second head chip from the first head chip in the first direction and has a second liquid channel communicating with the second head chip,

the first head chip is formed by overlapping a first actuator plate and a first cover plate in the first direction, the second head chip is formed by overlapping a second actuator plate and a second cover plate in the first direction,

the first channel member is provided with a first bubble discharge channel for communicating the inside and outside of the first liquid channel,

a second bubble discharge channel for communicating the inside and outside of the second liquid channel is formed in the second channel member,

the second head chip has an ejection region in which second pressure-varying chambers for imparting pressure variation to the liquid are arranged in a second direction intersecting the first direction,

a communication flow path that communicates the first liquid flow path and the second liquid flow path is provided between the first flow path member and the second flow path member in a pair in the second direction at a portion located on both sides of the ejection area,

the second bubble discharge flow path is communicated with the second liquid flow path at a central portion between the pair of communication flow paths in the second direction.

2. The liquid ejection head according to claim 1,

the first head chip has a first pressure variation chamber for imparting pressure variation to the liquid,

the second head chip has a second pressure fluctuation chamber for giving pressure fluctuation to the liquid,

the first head chip and the second head chip are provided with ejection orifice plates in which ejection orifices respectively communicating with the first pressure changing chamber and the second pressure changing chamber are formed,

in the injection orifice plate, a first discharge orifice communicating with the first bubble discharge channel and a second discharge orifice communicating with the second bubble discharge channel are opened in an injection surface in which the injection orifice is opened.

3. The liquid ejection head according to claim 2, wherein the first flow path member has an inflow port that connects a supply source of the liquid and the first liquid flow path,

the second discharge hole has an inner diameter smaller than that of the first discharge hole.

4. The liquid ejecting head according to claim 3, wherein a filter for filtering the liquid is disposed in the second bubble discharge channel.

5. The liquid ejecting head according to claim 1, wherein a filter for filtering the liquid is disposed in the second bubble discharge channel.

6. A liquid ejecting apparatus including the liquid ejecting head according to any one of claims 1 to 5.

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