JP6964978B2 - Liquid injection head and liquid injection device - Google Patents

Description

The present invention relates to a liquid injection head and a liquid injection device.

Conventionally, there is an inkjet printer provided with an inkjet head as a device for ejecting droplet-shaped ink onto a recording medium such as recording paper and recording an image or characters on the recording medium. The inkjet head is configured by mounting, for example, a plurality of head modules corresponding to each color on a carriage (for example, Patent Document 1 below).

The head module described above is configured such that, for example, a head chip that ejects ink, a manifold in which an ink flow path for supplying ink to the head chip is formed, and a drive substrate that drives the head chip are mounted on a base member.
The head chip described above includes an actuator plate in which a plurality of ejection channels filled with ink are arranged side by side. Of the actuator plates, drive electrodes are formed on the drive walls that define the discharge channels. In the head chip, by applying a drive voltage to the drive electrode, the drive wall is deformed and the volume in the discharge channel changes. As a result, the ink is ejected through the nozzle hole communicating with the ejection channel.

JP-A-2015-120265

By the way, in an inkjet head, when the base member is made of, for example, a conductive material, a stray capacitance is formed between the drive electrode and the base member. Therefore, the high frequency component of the drive voltage applied to the drive electrode may be transmitted to the base member via the stray capacitance, resulting in electrical noise. Further, when the drive board is fixed to the base member, electrical noise is transmitted to the drive board and causes a malfunction or the like in the electric circuit. Therefore, there is still room for improvement in the conventional inkjet head in terms of improving the operation reliability of the head chip.

The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a liquid injection head and a liquid injection device which suppress electric noise caused by stray capacitance and have excellent operation reliability. Is.

The liquid injection head according to one aspect of the present invention includes an injection hole plate having a plurality of injection hole rows in which injection holes extending in the first direction are arranged side by side in a second direction orthogonal to the first direction, and the injection hole plate. A head tip that is arranged in one of the first directions and has a channel that communicates with each of the injection holes, and a flow path member that has a liquid flow path that communicates with the channel are formed, and the head tip. A manifold supported by the manifold and a drive board supported by the manifold and electrically connected to the head chip are provided, and an insulating sheet is interposed between the flow path member and the head chip. ing. Further, the head chip and the drive substrate are supported by a first surface of the manifold facing the first direction and the third direction orthogonal to the second direction.

According to this configuration, since the insulating sheet is interposed between the head tip and the flow path member, the head tip and the flow path member can be electrically separated. Therefore, the stray capacitance generated between the head tip and the flow path member when the head tip is driven can be reduced. As a result, electrical noise to the drive board can be suppressed, and the operational reliability of the liquid injection head can be ensured. Further, since the head chip and the drive board are supported on the first surface of the manifold, the liquid is compared with, for example, a configuration in which the manifold and the drive board are separately arranged on both sides in the third direction with respect to the head chip. The injection head can be miniaturized in the third direction.

In the above aspect, the manifold includes the flow path member and a flow path cover that is overlapped with the flow path member and closes the liquid flow path, and the insulating sheet includes the flow path cover and the head tip. It may intervene between and.
According to this embodiment, the insulating sheet and the manifold by providing separately, unlike the case where an insulating sheet forms part of the manifold, it is possible to improve the flexibility of such material selection and design of the insulation sheet ..

In the above aspect, the manifold may include the flow path member and a flow path cover that is overlapped with the flow path member and closes the liquid flow path, and the flow path cover may be the insulating sheet. ..
According to this aspect, since the insulating sheet constitutes a part of the manifold, the number of parts can be reduced as compared with the case where the insulating sheet is provided separately from the manifold.

In the above aspect, the insulating sheet may be made of a material softer than the flow path member and the head tip.
According to this aspect, the stress acting on the head tip and the flow path member due to the difference in the coefficient of thermal expansion between the head tip and the flow path member can be relaxed. As a result, it is possible to suppress deformation or cracking of the head tip, peeling from the flow path member, misalignment of the head tip with respect to the manifold, etc. due to, for example, a difference in the coefficient of thermal expansion between the head tip and the flow path member.

In the above aspect, the insulating sheet may be made of polyimide.
According to this aspect, it is possible to provide an insulating sheet having excellent workability and adhesiveness.

In the above aspect, the head chip and the insulating sheet may be made of ceramics.
According to this aspect, since the difference in the coefficient of thermal expansion of the head tip and the insulating sheet can be reduced, the relative displacement of the head tip, the manifold and the insulating sheet due to the temperature change can be suppressed. Therefore, it is possible to suppress, for example, deformation or cracking of the head tip, peeling from the flow path member, misalignment of the head tip with respect to the manifold, etc. due to the difference in the coefficient of thermal expansion between the head tip and the flow path member.

The liquid injection device according to one aspect of the present invention includes the liquid injection head according to the above aspect.
According to this aspect, it is possible to provide a liquid injection device having excellent operation reliability.

According to one aspect of the present invention, it is possible to provide a liquid injection head and a liquid injection device having excellent operation reliability.

It is a schematic block diagram of the inkjet printer which concerns on embodiment. It is a perspective view of the inkjet head which concerns on embodiment. It is a perspective view which shows the state which removed a part of the inkjet head which concerns on embodiment. It is a perspective view of the 1st head module which concerns on embodiment. It is an exploded perspective view of the head tip which concerns on embodiment. It is an exploded perspective view of the manifold which concerns on embodiment. It is an exploded perspective view of the base member, the nozzle plate and the nozzle guard which concerns on embodiment. FIG. 5 is a partial bottom view of the inkjet head according to the embodiment as viewed from the −Z direction. It is sectional drawing of the head module which concerns on the modification of embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the following embodiment, an inkjet printer (hereinafter, simply referred to as a printer) that records on a recording medium using ink (liquid) will be described as an example. In the drawings used in the following description, the scale of each member is appropriately changed in order to make each member recognizable.

[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, an orthogonal coordinate system of X, Y, and Z will be used as necessary. In this case, the X direction (second direction) coincides with the transport direction (secondary scanning direction) of the recording medium P (for example, paper or the like). The Y direction (third direction) coincides with the scanning direction (main scanning direction) of the scanning mechanism 6. The Z direction (first direction) indicates a height direction orthogonal to the X direction and the Y direction. In the following description, of the X direction, the Y direction, and the Z direction, the direction indicated by the arrow in the figure is defined as the plus (+) direction, and the direction opposite to the arrow is defined as the minus (−) direction.

The transport mechanisms 2 and 3 transport the recording medium P in the + X direction. Specifically, the transport mechanism 2 includes a grit roller 11 extended in the Y direction, a pinch roller 12 extended in parallel with the grit roller 11, and a drive mechanism such as a motor for axially rotating the grit roller 11. (Illustrated) and. Similarly, the transport mechanism 3 includes a grit roller 13 extending in the Y direction, a pinch roller 14 extending parallel to the grit roller 13, and a drive mechanism (not shown) for axially rotating the grit roller 13. It has.

The ink supply mechanism 4 includes an ink tank 15 containing ink and an ink pipe 16 connecting the ink tank 15 and the inkjet heads 5A and 5B.
In this embodiment, a plurality of ink tanks 15 are arranged in the X direction. Each ink tank 15 contains inks of four colors, for example, yellow, magenta, cyan, and black.
The ink pipe 16 is, for example, a flexible hose having flexibility. The ink pipe 16 connects each ink tank 15 and each inkjet head 5A, 5B.

The scanning mechanism 6 reciprocates the inkjet heads 5A and 5B in the Y direction. Specifically, the scanning mechanism 6 moves the pair of guide rails 21 and 22 extending in the Y direction, the carriage 23 movably supported by the pair of guide rails 21 and 22, and the carriage 23 in the Y direction. It is provided with a drive mechanism 24 for driving.

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

The carriage 23 is connected to the endless belt 27. A plurality of inkjet heads 5A and 5B are mounted on the carriage 23 in a state of being arranged in the Y direction. Each of the inkjet heads 5A and 5B is configured to be capable of ejecting two colors of ink for each of the inkjet heads 5A and 5B. Therefore, in the printer 1 of the present embodiment, each of the inkjet heads 5A and 5B is configured to be capable of ejecting four colors of ink, yellow, magenta, cyan, and black, by ejecting inks of two different colors. ..

<Inkjet head>
FIG. 2 is a perspective view of the inkjet head 5A. The inkjet heads 5A and 5B have the same configuration 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, in the inkjet head 5A of the present embodiment, the head modules 30A to 30D, the damper 31, the nozzle plate (injection hole plate) 32, the nozzle guard (injection hole guard) 33, and the like are mounted on the base member 38. It is composed of. In FIG. 2, the cover and the like covering the head modules 30A to 30D and the damper 31 and the like are not shown.

(Base member)
FIG. 3 is a perspective view showing a state in which a part of the inkjet head 5A is removed.
As shown in FIG. 3, the base member 38 is formed in a plate shape with the Z direction as the thickness direction and the X direction as the longitudinal direction. The base member 38 has a module holding portion 41 for holding the head modules 30A to 30D, and a carriage fixing portion 42 for fixing the base member 38 to the carriage 23 (see FIG. 1). In this embodiment, the base member 38 is integrally formed of a metal material.

The module holding portion 41 is formed in a frame shape in a plan view seen from the Z direction. That is, a mounting opening 44 that penetrates the base member 38 in the Z direction is formed in the central portion of the module holding portion 41 on the XY plane. Insertion grooves 46 are formed in each of the pair of short side portions 45 located on both sides of the module holding portion 41 in the X direction. The insertion grooves 46 of the present embodiment are a plurality of insertion grooves 46 formed on each short side portion 45, with the insertion grooves 46 facing each other in the X direction as one set and spaced apart in the Y direction. (For example, four sets) are formed.

Each insertion groove 46 is recessed in the X direction with respect to the inner peripheral surface of the short side portion 45, and penetrates the short side portion 45 in the Z direction. That is, the insertion groove 46 communicates with the mounting opening 44. The head modules 30A to 30D can be inserted into the insertion grooves 46 of each set facing each other in the X direction. Of the insertion grooves 46 of each set, on the inner surface of one of the insertion grooves 46, a first urging member (1st urging member) that urges the head modules 30A to 30D toward the other insertion groove 46 in one direction in the X direction. (Not shown) is arranged. In the present embodiment, the first urging member is formed in a leaf spring shape.

The carriage fixing portion 42 projects from the + Z direction end portion of the module holding portion 41 in the XY plane. The carriage fixing portion 42 is formed with mounting holes and the like for mounting the base member 38 to the carriage 23 (see FIG. 1).

(Head module)
As shown in FIG. 2, the head modules 30A to 30D are configured so that the ink supplied from the ink tank 15 (see FIG. 1) can be ejected toward the recording medium P. A plurality of head modules 30A to 30D are mounted on the base member 38 at intervals in the Y direction. In this embodiment, four head modules, a first head module 30A, a second head module 30B, a third head module 30C, and a fourth head module 30D, are mounted on the base member 38.

In the inkjet head 5A of the present embodiment, two head modules out of the four head modules 30A to 30D eject ink of one color. Specifically, the first head module 30A and the second head module 30B are configured to be capable of ejecting ink of the same color, and the third head module 30C and the fourth head module 30D are configured to be capable of ejecting ink of the same color. The number of head modules 30A to 30D mounted on the base member 38, the type of ink ejected from the head modules 30A to 30D, and the like can be appropriately changed. Further, since each of the head modules 30A to 30D has a corresponding configuration, the first head module 30A will be described as an example in the following description.

FIG. 4 is a perspective view of the first head module 30A.
As shown in FIG. 4, the first head module 30A mainly includes a head chip 51, a manifold 52, and a drive board 53.

(Head tip)
FIG. 5 is an exploded perspective view of the head tip 51.
As shown in FIG. 5, the head tip 51 is a so-called edge shoot type that ejects ink from an end portion in the extending direction (Z direction) of the ejection channel 57, which will be described later. Specifically, the head tip 51 is configured by superimposing the actuator plate 55 and the cover plate 56 in the Y direction.

The actuator plate 55 is a so-called monopole substrate in which the polarization direction is set in one direction along the thickness direction (Y direction). As the actuator plate 55, for example, a ceramic substrate made of PZT (lead zirconate titanate) or the like is preferably used. Further, the actuator plate 55 may be formed by laminating two piezoelectric substrates having different polarization directions in the Y direction (so-called chevron type).

A plurality of channels 57 and 58 are arranged side by side at intervals in the X direction on the surface of the actuator plate 55 facing the + Y direction (hereinafter, referred to as “surface”). Each of the channels 57 and 58 is formed linearly along the Z direction. Each channel 57, 58 opens on the −Z direction end face of the actuator plate 55 and terminates at the + Z direction end of the actuator plate 55. It should be noted that the channels 57 and 58 may extend so as to be inclined with respect to the Z direction.

The plurality of channels 57 and 58 described above are the ejection channel 57 filled with ink and the non-ejection channel 58 not filled with ink. The discharge channels 57 and the non-discharge channels 58 are arranged alternately in the X direction. Each of the channels 57 and 58 is partitioned in the X direction by a drive wall 61 composed of an actuator plate 55. Drive electrodes (not shown) are formed on the inner surfaces of the channels 57 and 58.

The cover plate 56 is formed in a rectangular shape when viewed from the front in the Y direction. The cover plate 56 is joined to the surface of the actuator plate 55 with the + Z direction end of the actuator plate 55 protruding.

The cover plate 56 has a common ink chamber 62 formed on a surface facing the + Y direction (hereinafter referred to as “front surface”) and a plurality of slits 63 formed on a surface facing the −Y direction (hereinafter referred to as “back surface”). And have.
The common ink chamber 62 is formed at a position equivalent to the + Z direction end portion of the ejection channel 57 in the Z direction. The common ink chamber 62 is recessed from the surface of the cover plate 56 in the −Y direction and extends in the X direction. Ink flows into the common ink chamber 62 through the manifold 52 described above.
The slit 63 is formed in the common ink chamber 62 at a position facing the ejection channel 57 in the Y direction. The slit 63 communicates the inside of the common ink chamber 62 and the inside of each discharge channel 57 separately. On the other hand, the non-ejection channel 58 does not communicate with the common ink chamber 62.

As shown in FIG. 4, the heat transfer plate 65 is attached to the surface of the actuator plate 55 described above that faces the −Y direction (hereinafter, referred to as “back surface”). The heat transfer plate 65 is made of a material having excellent thermal conductivity (for example, aluminum or the like). The heat transfer plate 65 is provided on the back surface of the actuator plate 55 so as to cover the entire area of each of the channels 57 and 58. The size and position of the heat transfer plate 65 can be changed as appropriate.

(Manifold)
As shown in FIG. 3, the manifold 52 has an ink flow path 71 (see FIG. 6) through which ink flows toward the head chip 51 described above. The manifold 52 is formed in a plate shape with the Y direction as the thickness direction as a whole. The manifold 52 is held by the base member 38 in an upright state in the + Z direction by being inserted into a set of insertion grooves 46 facing each other in the X direction among the above-mentioned insertion grooves 46. As shown in FIG. 4, at the −Z direction end portion of the manifold 52, second urging members 70 are provided at both ends in the X direction. The second urging member 70 is interposed between the inner surface of the insertion groove 46 and the manifold 52 in the insertion groove 46 to urge the first head module 30A in the −Y direction. In the present embodiment, the second urging member 70 is formed in a leaf spring shape.

FIG. 6 is an exploded perspective view of the manifold 52.
As shown in FIG. 6, the manifold 52 has a flow path member 72 and a flow path cover 73 superposed on the flow path member 72 in the Y direction.
The flow path member 72 is integrally formed of a material having excellent thermal conductivity. In the present embodiment, a conductive metal material (for example, aluminum or the like) is preferably used as the material of the flow path member 72.

The flow path member 72 includes a flow path plate 75 and an inflow port 76.
The flow path plate 75 is formed in a rectangular plate shape with the Y direction as the thickness direction. An ink flow path 71 is formed on the surface of the flow path plate 75 facing the −Y direction. The ink flow path 71 is formed in a groove shape that is recessed in the + Y direction. Specifically, the ink flow path 71 has a meandering portion 79 and a communication portion 80.

The meandering portion 79 extends in the Z direction while meandering in the X direction. The + Z direction end of the meandering portion 79 communicates with the inflow port 76. On the other hand, the end portion in the −Z direction of the meandering portion 79 communicates with the communication portion 80 at the central portion in the X direction of the flow path plate 75. The meandering direction of the meandering portion 79 is longer than the straight line connecting the communicating portion between the meandering portion 79 and the inflow port 76 and the communicating portion between the meandering portion 79 and the communicating portion 80. If so, it can be changed as appropriate. For example, the meandering portion 79 may be configured to meander in the Z direction and extend in the X direction.
The communication portion 80 extends in the X direction at the end portion of the flow path plate 75 in the −Z direction. The communication portion 80 has the same shape as the common ink chamber 62 described above when viewed from the Y direction.

In the first head module 30A, the inflow port 76 is provided at the end of the flow path plate 75 in the + Z direction at the end in the −X direction. The inflow port 76 is formed in a cylindrical shape protruding from the flow path plate 75 in the + Z direction. The −Z direction end of the inflow port 76 communicates with the meandering portion 79 described above.

The flow path cover 73 has an outer shape equivalent to that of the flow path plate 75 when viewed from the front in the Y direction, and is formed in a rectangular plate shape having a thickness in the Y direction thinner than that of the flow path plate 75. The flow path cover 73 is fixed to the surface of the flow path plate 75 facing the −Y direction, and closes the ink flow path 71 described above from the −Y direction. A communication hole 82 for opening the communication portion 80 is formed at a position of the flow path cover 73 that overlaps with the communication portion 80 when viewed from the Y direction. The communication hole 82 has the same shape as the communication portion 80 when viewed from the Y direction.

In the present embodiment, the flow path cover 73 is made of a conductive metal material (for example, stainless steel) having excellent thermal conductivity. Further, in the present embodiment, the case where the groove-shaped ink flow path 71 is formed only in the flow path member 72 has been described, but the present invention is not limited to this configuration, and at least one of the flow path member 72 and the flow path cover 73 is not limited to this configuration. It does not matter if the ink flow path is formed in. In this case, for example, a groove may be formed in each of the flow path member 72 and the flow path cover 73, and the groove portions of the flow path member 72 and the flow path cover 73 may be overlapped to form an ink flow path.

An insulating sheet (insulator) 86 is provided on the surface of the flow path cover 73 facing the −Y direction. The insulating sheet 86 is formed in a frame shape when viewed from the front in the Y direction. The insulating sheet 86 surrounds the communication hole 82 on the surface of the flow path cover 73 facing the −Y direction. The insulating sheet 86 is fixed to the surface of the flow path cover 73 facing the −Y direction by adhesion or the like. In the present embodiment, for example, polyimide is preferably used as the insulating sheet 86. However, the material of the insulating sheet 86 has characteristics that can sufficiently reduce the stray capacitance (a material having a low dielectric constant, a material that can reduce the dielectric constant in a short space distance, etc.) and ink resistance (material resistance). It can be appropriately changed as long as it is made of a material (for example, a resin material (plastic) or a rubber material) that has (dissolvability) and is softer (smaller Young ratio) than the head tip 51 or the manifold 52.

Here, as shown in FIGS. 4 and 6, the above-mentioned head tip 51 is placed on the surface of the flow path cover 73 facing the −Y direction (the first surface facing the third direction) with the insulating sheet 86 interposed therebetween. It is fixed to. Specifically, the head tip 51 is fixed to the insulating sheet 86 by adhesion or the like with the surface of the cover plate 56 (the surface facing the manifold 52) facing the insulating sheet 86. At this time, the common ink chamber 62 of the cover plate 56 communicates with the communication portion 80 through the communication hole 82. As a result, the ink circulating in the ink flow path 71 is supplied to the head chip 51. The head tip 51 projects in the −Z direction with respect to the manifold 52 in a state of being fixed to the manifold 52. Further, in the example shown in FIG. 4, the length of the head tip 51 in the X direction is shorter than the length of the manifold 52 in the X direction.

As shown in FIG. 2, the heater 85 is arranged on the surface of the flow path member 72 (flow path plate 75) facing the + Y direction (the second surface facing the third direction). The heater 85 heats the inside of the ink flow path 71 through the flow path member 72 to keep the ink flowing in the ink flow path 71 within a predetermined temperature range (heat retention).

As shown in FIG. 4, the drive board 53 is a so-called flexible printed circuit board, and is configured by mounting a wiring pattern and various electronic components on a base film. The drive board 53 includes a module control unit 88 supported by the manifold 52, and a chip connection unit 89 that connects the module control unit 88 and the head chip 51. As for the drive board 53, a rigid board or the like may be used for the module control unit 88 as long as at least the chip connection part 89 is composed of a flexible board.

The module control unit 88 is formed in a rectangular shape when viewed from the front in the Y direction. Electronic components such as a driver IC are mounted on the module control unit 88. The module control unit 88 is fixed to the manifold 52 with a support plate 90 sandwiched between portions located in the + Z direction with respect to the head tip 51 on the surface of the flow path cover 73 facing the −Y direction. The support plate 90 is made of a material having excellent thermal conductivity (for example, a metal material). The support plate 90 may not be provided. That is, the module control unit 88 may be directly fixed to the manifold 52.

As shown in FIG. 2, the drive board 53 is electrically connected to the external connection board 92 via a drawer 91 drawn from the module control unit 88 in the + Z direction. The external connection board 92 relays control signals and drive voltages to the head modules 30A to 30D (driver ICs) output from the main control board (not shown) mounted on the printer 1. Then, the drive board 53 drives the head chip 51 based on the control signal and the drive voltage relayed by the external connection board 92.

As shown in FIG. 4, the chip connecting portion 89 extends in the −Z direction from the module control unit 88 with a gap in the Y direction with respect to the flow path cover 73. The −Z direction end portion of the chip connection portion 89 is fixed to the + Z direction end portion of the actuator plate 55 described above by crimping or the like. As a result, the drive substrate 53 and the drive electrode of the head chip 51 are electrically connected.

The drive board 53 includes a sensor connection unit 93 drawn out from the + X direction end of the module control unit 88. The sensor connection portion 93 is extended to a position where it overlaps with the heat transfer plate 65 described above when viewed from the Y direction. A temperature sensor 94 (for example, a thermistor) that detects the ink temperature in the ejection channel 57 is mounted on the tip of the sensor connection portion 93. The temperature sensor 94 is arranged on the back surface of the actuator plate 55 with a heat transfer plate 65 sandwiched between them.

As shown in FIG. 3, the first head module 30A is inserted into the mounting opening 44 with the manifold 52 inserted into the insertion groove 46 as described above. At this time, in the first head module 30A, the head tip 51 faces the −Y direction, and the −Z direction end face of the head tip 51 is flush with the −Z direction end surface of the base member 38 (module holding portion 41). Is held by the base member 38.

As shown in FIGS. 2 and 3, the second head module 30B is inserted into the insertion groove 46 adjacent to the insertion groove 46 into which the manifold 52 of the first head module 30A is inserted in the −Y direction. In this state, it is inserted into the mounting opening 44. At this time, the second head module 30B is held by the base member 38 with the head tip 51 facing the head tip 51 of the first head module 30A in the Y direction. Further, the inflow ports 76 of the first head module 30A and the second head module 30B are arranged at the same positions in the X direction.

The head tips 51 of the second head module 30B are arranged (staggered) with the arrangement pitch of the discharge channels 57 deviating by half a pitch from the head chips 51 of the first head module 30A. As a result, the head chips 51 of the first head module 30A and the second head module 30B cooperate to eject one color of ink, so that characters and images recorded on the recording medium P can be recorded at high density. It has become. In the first head module 30A and the second head module 30B, the arrangement pitch of the discharge channels 57 of the head tip 51 can be changed as appropriate.

Further, as shown in FIG. 2, the third head module 30C and the fourth head module 30D are the same as the first head module 30A and the second head module 30B described above in a state where the head chips 51 are facing each other. It is held by the base member 38 by the method. The head modules 30A to 30D are fixed to the base member 38 via stays (not shown) erected in the + Z direction from the base member 38. The inflow port 76 of the third head module 30C and the fourth head module 30D is on the opposite side of the inflow port 76 of the first head module 30A and the second head module 30B in the X direction (+ X direction in the flow path plate 75). Is located at the end of the module).

(damper)
The damper 31 is provided in the + Z direction with respect to the head modules 30A to 30D, corresponding to the color of the ink. That is, one damper 31 of the present embodiment is provided for each of the two head modules (for example, the head modules 30A and 30B). The dampers 31 are provided side by side in the Y direction. Each damper 31 has the same configuration except for the color of the supplied ink. Therefore, in the following description, one damper 31 (damper for head modules 30A and 30B) will be described, and the description of the other damper 31 will be omitted.

The damper 31 is attached to the head modules 30A and 30B in the + Z direction via a stay (not shown) fixed to the base member 38. The damper 31 has an inlet port 100, a pressure buffer 101, and an outlet port 102. The damper 31 may be provided separately from the inkjet head 5A.

The inlet port 100 is formed in a cylindrical shape protruding from the pressure buffer 101 in the + Z direction. The ink pipe 16 (see FIG. 1) described above is connected to the inlet port 100. In the inlet port 100, the ink in the ink tank 15 flows in through the ink pipe 16.
The pressure buffer 101 is formed in a box shape. The pressure buffer portion 101 is configured such that a movable membrane or the like is housed inside the pressure buffer portion 101. The pressure buffer 101 is arranged between the ink tank 15 (FIG. 1) and the head modules 30A and 30B, and absorbs the pressure fluctuation of the ink supplied to the damper 31 through the inlet port 100.
The outlet port 102 is formed in a cylindrical shape protruding from the pressure buffer 101 in the −X direction. Ink discharged from the pressure buffer 101 flows into the outlet port 102.

A filter unit 110 is connected to the outlet port 102. The filter unit 110 contains a filter (not shown) inside. The filter unit 110 removes air bubbles, foreign substances, and the like contained in the ink discharged from the damper 31 with a filter. The filter unit 110 has branching portions 111 and 112 for bifurcating the ink discharged from the damper 31. One branch portion 111 is connected to the inflow port 76 of the first head module 30A via the connection tube 113. The other branch portion 112 is connected to the inflow port 76 of the second head module 30B via the connection tube 114. The filter unit 110 is fixed to the base member 38 via a stay (not shown). Further, the above-mentioned external connection board 92 is arranged between the dampers 31 facing each other in the Y direction.

FIG. 7 is an exploded perspective view of the base member 38, the nozzle plate 32, and the nozzle guard 33.
As shown in FIG. 7, of the above-mentioned base member 38, the spacer 120 is fixed to the −Z direction end surface (plate arrangement surface) of the module holding portion 41. The spacer 120 is made of polyimide, SUS, or the like. The spacer 120 is adhered to the end face of the module holding portion 41 in the −Z direction using a soft adhesive. As the soft adhesive, a silicone-based adhesive (for example, manufactured by ThreeBond Co., Ltd.: 1211) or the like is preferably used.

The spacer 120 covers the end face of the module holding portion 41 in the −Z direction from the −Z direction. A spacer opening 121 that exposes the head tip 51 in the −Z direction is formed at a position of the spacer 120 that overlaps the head tip 51 of each of the head modules 30A to 30D when viewed from the Z direction. In the present embodiment, the spacer opening 121 exposes the head tips 51 for each color (for example, the head tips 51 of the first head module 30A and the second head module 30B) together. The spacer opening 121 may expose the head tips 51 of the head modules 30A to 30D together, or each head tip 51 may be exposed.

(Nozzle plate)
The nozzle plate 32 described above is made of a resin material such as polyimide. The + Z direction end face (opposing surface to the base member 38) of the nozzle plate 32 is fixed to the above-mentioned spacer 120 and the −Z direction end face of the head tip 51 with a hard adhesive. The hard adhesive is made of a material that is harder, for example, with a shore hardness as compared with the soft adhesive described above. As such a material, an epoxy adhesive (for example, manufactured by Able Stick Co., Ltd .: 931-1T1N1) or the like is preferably used. The nozzle plate 32 may be directly adhered to the base member 38 using a soft adhesive.

As shown in FIGS. 2 and 7, the nozzle plate 32 collectively covers the head tips 51 of the head modules 30A to 30D from the −Z direction. A plurality of nozzle rows (first nozzle row 130A to fourth nozzle row 130D) extending in the X direction are formed on the nozzle plate 32 at intervals in the Y direction.
The nozzle rows (injection hole rows) 130A to 130D are formed at positions of the nozzle plates 32 facing the head tips 51 of the corresponding head modules 30A to 30D in the Z direction.

FIG. 8 is a partial bottom view of the inkjet head 5A as viewed from the −Z direction.
As shown in FIG. 8, each nozzle row 130A to 130D has a nozzle hole (first nozzle hole 131A to fourth nozzle hole 131D) penetrating the nozzle plate 32 in the Z direction. For example, the first nozzle hole (injection hole) 131A is separately formed in the nozzle plate 32 at a position facing the discharge channel 57 of the head tip 51 in the first head module 30A in the Z direction. That is, the plurality of first nozzle holes 131A are formed linearly with an interval in the X direction to form the first nozzle row 130A.
The second nozzle hole 131B, the third nozzle hole 131C, and the fourth nozzle hole 131D are the head tips 51 of the corresponding head modules 30B to 30D among the nozzle plates 32, similarly to the first nozzle hole 131A described above. Each is separately formed at a position facing the discharge channel 57 in the Z direction.

As shown in FIG. 7, a slit 135 that penetrates the nozzle plate 32 in the Z direction is formed in a portion of the nozzle plate 32 located between the second nozzle row 130B and the third nozzle row 130C in the Y direction. Has been done. In the present embodiment, the slits 135 are formed in two rows at intervals in the Y direction. The slit 135 extends parallel to the nozzle rows 130A to 130D along the X direction. Further, the length of the slit 135 in the X direction is longer than that of the nozzle rows 130A to 130D. However, the length of the slit 135 can be appropriately changed as long as it is shorter than the length of the nozzle plate 32 in the X direction. Further, the number of slits 135 is not limited to two rows and can be changed as appropriate.

The nozzle plate 32 is not limited to the resin material, and may be formed of a metal material (stainless steel or the like), or may have a laminated structure of the resin material and the metal material. However, the nozzle plate 32 is preferably a material having a coefficient of thermal expansion equivalent to that of the spacer 120. Further, the end face of the nozzle plate 32 in the −Z direction is subjected to a liquid repellent treatment. In the present embodiment, the configuration in which one nozzle plate 32 covers each of the head modules 30A to 30D together has been described, but the present invention is not limited to this configuration, and each head module 30A to 30D is individually covered by a plurality of nozzle plates 32. It may be configured to cover with. The nozzle plate 32 may not be treated with a liquid repellent treatment.

(Nozzle guard)
The nozzle guard 33 is formed by pressing a plate material such as stainless steel. The nozzle guard 33 covers the module holding portion 41 from the −Z direction with the nozzle plate 32 and the spacer 120 sandwiched between them.

An exposed hole 141 is formed in the nozzle guard 33 at a position facing the nozzle rows 130A to 130D described above in the Z direction to expose the nozzle rows 130A to 130D to the outside. The exposed hole 141 penetrates the nozzle guard 33 in the Z direction and is formed in a slit shape extending in the X direction. The exposed holes 141 of the present embodiment are formed in two rows at intervals in the Y direction corresponding to the nozzle rows 130A to 130D for ejecting ink of the same color. That is, one of the exposed holes 141 exposes the first nozzle row 130A and the second nozzle row 130B to the outside. The other exposed hole 141 exposes the third nozzle row 130C and the fourth nozzle row 130D to the outside.

As shown in FIG. 8, the nozzle guard 33 is fixed to the spacer 120 described above by adhesion or the like. Specifically, the nozzle guard 33 is adhered to a portion of the spacer 120 located outside the nozzle plate 32 in a plan view from the Z direction (hereinafter, referred to as “first adhesive region 150”). The first adhesive region 150 is set in a frame shape that surrounds the periphery of the nozzle plate 32 over the entire circumference. The first adhesive region 150 may be adhered to the outer peripheral edge of the nozzle plate 32 as long as it is adhered to the spacer 120 at least outside the nozzle plate 32.

Further, the nozzle guard 33 is adhered to a portion of the spacer 120 exposed through the slit 135 described above of the nozzle plate 32 (hereinafter, referred to as “second adhesive region 151”). That is, the second bonding region 151 extends parallel to the nozzle rows 130A to 130D along the X direction. As a result, the second bonding region 151 partitions between the nozzle rows of different colors (between the second nozzle row 130B and the third nozzle row 130C) among the nozzle rows 130A to 130D.

[How the printer works]
Next, a method of recording information on the recording medium P by using the printer 1 described above will be described.
As shown in FIG. 1, when the printer 1 is operated, the grit rollers 11 and 13 of the transport mechanisms 2 and 3 rotate, so that the recording medium P is placed between the grit rollers 11 and 13 and the pinch rollers 12 and 14. It is conveyed in the + X direction. At the same time, the drive motor 28 rotates the pulley 26 to run the endless belt 27. As a result, the carriage 23 reciprocates in the Y direction while being guided by the guide rails 21 and 22.
During this time, a drive voltage is applied to the drive electrodes of the head chip 51 in each of the inkjet heads 5A and 5B. As a result, the drive wall 61 is deformed by a thickness slip, and a pressure wave is generated in the ink filled in the ejection channel 57. Due to this pressure wave, the internal pressure of the ejection channel 57 increases, and ink is ejected through the nozzle holes 131A to 131D. Then, when the ink lands on the recording medium P, various information is recorded on the recording medium P.

Here, in the present embodiment, for example, in the first head module 30A, the head chip 51 and the drive substrate 53 are supported by the manifold 52 having the ink flow path 71.
According to this configuration, the member supporting the head chip 51 and the drive substrate 53 and the ink flow path 71 are integrated with the manifold 52 arranged on one side in the Y direction with respect to the head chip 51. As a result, as in the conventional case, a member that supports the head chip and the drive substrate is arranged on one side in the Y direction with respect to the head chip, and a member having an ink flow path on the other side in the Y direction is separately arranged with respect to the head chip. It is possible to reduce the size of the first head module 30A in the Y direction (main scanning direction) as compared with the configuration. This makes it possible to reduce the size of the inkjet head 5A in the Y direction.
Further, the heat generated in the head chip 51 and the drive substrate 53 is dissipated to the outside via the manifold 52. As a result, the heat dissipation performance of the head chip 51 and the drive substrate 53 can be ensured.
Further, since the head chip 51 and the drive board 53 are supported by the manifold 52 having the ink flow path 71, the ink flow path uses the exhaust heat generated by the head chip 51 and the drive board 53 and transmitted to the manifold 52. It is also possible to heat (keep warm) the ink flowing through 71. As a result, the ink can be supplied to the head chip 51 at a desired temperature (viscosity), and excellent printing characteristics can be obtained.
Moreover, in the present embodiment, since the head modules 30A to 30D can be miniaturized in the Y direction, a manifold 52 can be provided for each head chip 51. Therefore, in order to achieve high-density recording, the heat dissipation performance of each head chip 51 can be ensured as compared with the configuration in which a plurality of head chips 51 are mounted on one head module 30A to 30D.

In the present embodiment, since the damper 31 is arranged in the + Z direction with respect to the manifold 52, the size of the inkjet head 5A in the Y direction is reduced as compared with the configuration in which the damper 31 and the manifold 52 are provided side by side in the Y direction. Can be planned.

In the present embodiment, since the ink flow path 71 meanders and extends, the exhaust heat of the head chip 51 and the drive substrate 53 can be effectively transferred to the ink in the ink flow path 71. As a result, the ink can be supplied to the head chip 51 at a desired temperature (viscosity), and excellent printing characteristics can be obtained.

In the present embodiment, the heater 85 is arranged on the surface of the manifold 52 facing the + Y direction (the surface opposite to the surface supporting the drive substrate 53).
According to this configuration, the ink circulating in the ink flow path 71 can be heated not only by the exhaust heat of the head chip 51 and the drive substrate 53 but also by the heater 85, so that the ink can be reliably delivered to the head chip 51 at a desired temperature. Can be supplied.

In the present embodiment, since the insulating sheet 86 is interposed between the head tip 51 and the manifold 52, the head tip 51 and the manifold 52 can be electrically separated from each other. Therefore, the stray capacitance generated between the head tip 51 and the manifold 52 when the head tip 51 is driven can be reduced. As a result, electrical noise to the drive substrate 53 can be suppressed, and the operational reliability of the inkjet head 5A can be ensured.
Further, by using a material having ink resistance such as polyimide for the insulating sheet 86, it is possible to suppress the insulating sheet 86 from being eluted by the ink and suppress the ejection failure. Further, by forming the insulating sheet 86 with polyimide, it is possible to provide the insulating sheet 86 having excellent workability and adhesiveness.

Further, by using a soft material such as polyimide for the insulating sheet 86, the stress acting on the head tip 51 and the manifold 52 due to the difference in the coefficient of thermal expansion between the head tip 51 and the manifold 52 can be relaxed. As a result, for example, deformation or cracking of the head tip 51, peeling from the manifold 52, misalignment of the head tip 51 with respect to the manifold 52, and the like can be suppressed.
Moreover, by providing the insulating sheet 86 separately from the manifold 52, it is possible to improve the degree of freedom in material selection and design of the insulating sheet 86, unlike the case where the insulating sheet 86 constitutes a part of the manifold 52. can. An insulator may be interposed between the drive board 53 and the manifold 52.

In the present embodiment, the nozzle plate 32 having the nozzle rows 130A to 130D corresponding to the head modules 30A to 30D is arranged on the end face in the −Z direction of the base member 38.
According to this configuration, the positional accuracy of the nozzle holes 131A to 131D can be improved as compared with the configuration in which the nozzle plates 32 are attached to the head modules 30A to 30D respectively.

In the present embodiment, since the spacer 120 is interposed between the nozzle plate 32 and the base member 38, the nozzle plate 32 and the base member 38 are caused by the difference in the coefficient of thermal expansion between the nozzle plate 32 and the base member 38. The stress acting on and can be relaxed.
Further, in the present embodiment, since the spacer 120 is adhered to the base member 38 with a soft adhesive, it acts on the spacer 120 and the base member 38 due to the difference in the coefficient of thermal expansion between the spacer 120 and the base member 38. The stress to be applied can be surely relaxed.
As a result, it is possible to prevent the nozzle plate 32 from peeling off from the head tip 51.

In the present embodiment, the first bonding region 150 between the nozzle guard 33 and the spacer 120 is arranged so as to surround the periphery of the nozzle plate 32.
According to this configuration, when the ink adhering to the end faces of the nozzle plate 32 and the nozzle guard 33 in the −Z direction tries to enter the inkjet head 5A through the gap between the nozzle plate 32 and the nozzle guard 33, the ink adheres to the ink jet head 5A. Ink can be blocked by one adhesive region 150. As a result, it is possible to prevent the ink from entering the inside of the inkjet head 5A.

In the present embodiment, the second bonding region 151 of the nozzle guard 33 and the spacer 120 is arranged between the nozzle rows 130B and 130C in which different color inks are ejected from the nozzle rows 130A to 130D. bottom.
According to this configuration, the different color ink adhering to the end face in the −Z direction of the nozzle plate 32 and the like is blocked by the second adhesive region 151. As a result, it is possible to prevent inks of different colors from being mixed and leaking to the outside of the inkjet head 5A.

In the present embodiment, between the base member 38 and the head modules 30A to 30D, the first urging member and the second urging member for urging the base member 38 and the head modules 30A to 30D in either the X direction or the Y direction. The configuration is such that the force member 70 is interposed.
According to this configuration, the head modules 30A to 30D are held by the base member 38 in a state of being pressed in either the X direction or the Y direction. Therefore, the head modules 30A to 30D can be positioned with high accuracy with respect to the base member 38. Thereby, when the head modules 30A to 30D are subsequently fixed to the base member 38 via a stay or the like, the assembling property can be improved.

In the present embodiment, since the temperature sensor 94 is arranged on the back surface of the actuator plate 55, the ink temperature of the ejection channel 57 can be detected more accurately than when the temperature sensor 94 is arranged at a position separated from the actuator plate 55. ..
In particular, in the present embodiment, a heat transfer plate 65 is provided between the temperature sensor 94 and the actuator plate 55 so as to cover the entire area of each of the channels 57 and 58. Therefore, the average ink temperature in all the ejection channels 57 can be detected.

Since the printer 1 of the present embodiment includes the inkjet head 5A described above, it is possible to provide the printer 1 having excellent reliability while reducing the size in the Y direction.

In the above-described embodiment, the case where the insulating sheet 86 is formed of a relatively soft material has been described, but the present invention is not limited to this configuration, and the insulating sheet 86 is made of a material having a coefficient of thermal expansion close to that of the head tip 51 or the manifold 52. May be formed. As such a material, ceramics (particularly, machinable ceramics) and the like can be adopted.
According to this configuration, the difference in thermal expansion coefficient between the head tip 51, the manifold 52, and the insulating sheet 86 can be reduced, so that the relative displacement of the head tip 51, the manifold 52, and the insulating sheet 86 due to a temperature change can be suppressed. Therefore, due to the difference in the coefficient of thermal expansion of the head tip 51, the manifold 52, and the insulating sheet 86, for example, the head tip 51 is deformed or cracked, peeled off from the manifold 52, or the head tip 51 is misaligned with respect to the manifold 52. Can be suppressed.

In the above-described embodiment, the case where the manifold 52 has conductivity has been described, but the present invention is not limited to this configuration, and the manifold 52 may be formed of an insulating material. Even when a conductive member is attached to the insulating manifold 52, electrical noise to the drive board may occur due to the stray capacitance described above. Therefore, as in the above-described embodiment, by interposing the insulating sheet 86 between the head tip 51 and the manifold 52, electrical noise can be suppressed and the operation reliability of the inkjet head 5A can be ensured.

In the above-described embodiment, the configuration in which the insulating sheet 86 is provided separately from the manifold 52 has been described, but the configuration is not limited to this configuration. Like the manifold 252 of the head module 230 shown in FIG. 9, the flow path cover 273 itself may be formed of an insulator.
According to this configuration, since the insulator forms a part of the manifold 252, the number of parts can be reduced as compared with the case where the insulator is provided separately from the manifold 252.

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

For example, in the above-described embodiment, the inkjet printer 1 has been described as an example of the liquid injection device, but the present invention is not limited to the printer. For example, it may be a fax machine, an on-demand printing machine, or the like.

In the above-described embodiment, the configuration in which four head modules 30A to 30D are mounted on the base member 38 has been described, but the configuration is not limited to this configuration. The number of head modules mounted on the base member 38 may be one or a plurality.
In the above-described embodiment, the configuration in which one color ink is ejected by two head modules has been described, but the present invention is not limited to this configuration, and one color ink may be ejected by three or more head modules. One head module may eject one color of ink.

In the above-described embodiment, the head tip of the edge chute has been described, but the present invention is not limited to this. For example, the present invention may be applied to a so-called side shoot type head tip that ejects ink from the central portion of the ejection channel in the extending direction.
Further, the present invention may be applied to a so-called roof chute type head chip in which the direction of pressure applied to ink and the direction of ejection of ink droplets are the same.

In the above-described embodiment, the configuration in which the head chip 51 and the drive substrate 53 are supported on the same surface of the manifold has been described, but the configuration is not limited to this configuration. For example, the head chip 51 and the drive substrate 53 may be supported on different surfaces of the manifold 52 (for example, both sides facing the Y direction).

In addition, it is possible to replace the constituent elements in the above-described embodiments with well-known constituent elements as appropriate without departing from the spirit of the present invention, and the above-mentioned modifications may be appropriately combined.

(1) A damper that is connected to the liquid flow path and absorbs pressure fluctuations of the liquid supplied to the liquid flow path on the side opposite to the injection hole plate in the first direction with respect to the manifold. A liquid injection head, characterized in that

(2) A liquid injection head characterized in that the liquid flow path meanders and extends.

(3) A liquid injection head characterized in that a heater is disposed on the second surface of the manifold facing the third direction.

(4) An insulating sheet is interposed between the first surface of the manifold and the surface of the head chip facing the first surface of the manifold facing the third direction. Characterized liquid injection head.

(5) The head chip, the manifold, and the drive board form a head module, and a plurality of the head modules are mounted on a base member in a state of being arranged in the third direction, and a plurality of injection hole plates are provided. A liquid injection characterized by having a plurality of injection hole rows corresponding to the head chips in the head module and being arranged on a plate arrangement surface of the base member facing the other in the first direction. head.

(6) A spacer is interposed between the plate arranging surface of the base member and the surface of the injection hole plate facing the plate arranging surface of the base member facing the first direction. A liquid injection head characterized by that.

(7) The spacer is adhered to the base member with a soft adhesive, and the injection hole plate is adhered to the spacer with a hard adhesive formed of a material harder than the soft adhesive. A liquid injection head characterized by.

(8) On the other side of the injection hole plate in the first direction, there is an exposed hole that exposes the injection hole row to the outside, and an injection hole guard that covers the injection hole plate from the other side in the first direction. Is arranged, the injection hole plate is formed smaller than the outer shape of the spacer in a plan view seen from the first direction, and the injection hole guard is formed in a plan view seen from the first direction. A liquid injection head characterized in that the spacer is adhered to the spacer in an outer region, and the bonding portion between the injection hole guard and the spacer surrounds the periphery of the injection hole plate.

(9) The plurality of head modules include a first head module capable of discharging a first liquid and a second head module capable of discharging a second liquid different in color from the first liquid, and the injection thereof. The injection hole plate is provided in a portion of the hole plate located between the first injection hole row corresponding to the first head module and the second injection hole row corresponding to the second head module. A slit penetrating in the first direction and partitioning the first injection hole row and the second injection hole row is formed, and the injection hole guard is adhered to the spacer through the slit. Liquid injection head.

(10) The base member is formed with a mounting opening into which the head module is inserted while penetrating the base member in the first direction. A liquid injection head characterized in that an urging member for urging the head module and the base member is interposed in at least one of the second direction and the third direction.

1 ... Inkjet printer (liquid injection device)
5A, 5B ... Inkjet head (liquid injection head)
30A ... 1st head module (head module)
30B ... 2nd head module (head module, 1st head module)
30C ... 3rd head module (head module, 2nd head module)
30D ... 4th head module (head module)
31 ... Damper 32 ... Nozzle plate (injection hole plate)
33 ... Nozzle guard (injection hole guard)
38 ... Base member 44 ... Mounting opening 51 ... Head tip 52 ... Manifold 53 ... Drive board 57 ... Discharge channel (channel)
70 ... Second urging member (urging member)
71 ... Ink flow path (liquid flow path)
72 ... Flow path member 73 ... Flow path cover 79 ... Meandering part 85 ... Heater 86 ... Insulation sheet (insulator)
252 ... Manifold 273 ... Flow path cover (insulator)
120 ... Spacer 130A ... First nozzle row (injection hole row)
130B ... Second nozzle row (injection hole row, first injection hole row)
130C ... Third nozzle row (injection hole row, second injection hole row)
130D ... 4th nozzle row (injection hole row)
131A ... 1st nozzle hole (injection hole)
131B ... 2nd nozzle hole (injection hole)
131C ... Third nozzle hole (injection hole)
131D ... 4th nozzle hole (injection hole)
141 ... Exposed hole 150 ... First adhesive region (adhesive portion)

Claims (7)

An injection hole plate having a plurality of injection hole rows having a plurality of injection holes extending in the first direction arranged side by side in the second direction orthogonal to the first direction.
A head tip that is arranged in one of the first directions with respect to the injection hole plate and has a channel that communicates with the injection hole separately.
A manifold having a flow path member in which a liquid flow path communicating with the channel is formed and supporting the head tip, and a manifold for supporting the head tip.
A drive board supported by the manifold and electrically connected to the head chip,
With
An insulating sheet is interposed between the flow path member and the head tip .
The head chip and the drive substrate are liquid injection heads supported on the first surface of the manifold facing the first direction and the third direction orthogonal to the second direction. The manifold is
With the flow path member
A flow path cover that is overlapped with the flow path member and closes the liquid flow path,
With
The liquid injection head according to claim 1, wherein the insulating sheet is interposed between the flow path cover and the head tip. The manifold is
With the flow path member
A flow path cover that is overlapped with the flow path member and closes the liquid flow path,
With
The liquid injection head according to claim 1, wherein the flow path cover is the insulating sheet. The liquid injection head according to any one of claims 1 to 3, wherein the insulating sheet is made of a material softer than the flow path member and the head tip. The liquid injection head according to claim 4, wherein the insulating sheet is made of polyimide. The liquid injection head according to any one of claims 1 to 3, wherein the head tip and the insulating sheet are made of ceramics. A liquid injection device including the liquid injection head according to any one of claims 1 to 6.

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