Liquid injection head and liquid injection device

Abstract

To enable temperatures of a plurality of driving circuit to cool uniformly.SOLUTION: A liquid jet head, which comprises a plurality of head chips that jet liquid in a jetting direction, further comprises: an introducing part that introduces gas supplied from a gas supply mechanism to the inside of the liquid jet head; an ejecting part that ejects gas supplied to the introducing part to the outside of the liquid jet head; and a plurality of driving circuits provided in the plurality of head chips respectively. The plurality of driving circuits include a first driving circuit for driving the first head chip and a second driving circuit for driving the second head chip. A gas passage through which gas flows from the introducing part to the ejecting part has a first passage connected to the introducing part, a second passage connected to the ejecting part, a first branched passage connecting the first passage to the second passage, and a second branched passage connecting the first passage to the second passage without passing through the first branched passage. The first driving circuit is arranged in the first branched passage and the second driving circuit is arranged in the second branched passage.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a liquid ejection head and a liquid ejection device.

Background Art

[0002] Conventionally, a liquid ejection device that forms an image on a medium such as printing paper by ejecting a liquid such as ink based on image data indicating an image is known. For example, Patent Document 1 discloses a liquid ejection device having a plurality of head chips and a plurality of drive circuits for driving each of the plurality of head chips, and arranging the drive circuit having the largest calorific value among the plurality of drive circuits closest to the air intake. By arranging the drive circuit with the largest calorific value closest to the air intake, the drive circuit with the largest calorific value can be efficiently cooled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, depending on the image indicated by the image data, the calorific value of the drive circuit arranged closest to the air intake is not necessarily larger than the calorific values of the other drive circuits. Therefore, in the conventional liquid ejection head described above, there is a possibility that the plurality of drive circuits cannot be cooled uniformly.

Means for Solving the Problems

[0005] A liquid injection head according to a preferred embodiment of the present invention is a liquid injection head comprising a plurality of head tips for injecting liquid in the injection direction, comprising: one or more introduction sections for introducing gas supplied from a gas supply mechanism into the liquid injection head; an discharge section for discharging the gas supplied to the one or more introduction sections to the outside of the liquid injection head; and a plurality of drive circuits provided on each of the plurality of head tips, wherein the plurality of head tips include a first head tip and a second head tip, and the plurality of drive circuits drive the first head tip. The gas path, through which gas flows from one or more inlets to the outlet, includes a first drive circuit for driving the second head chip and a second drive circuit for driving the second head chip, wherein the gas path includes a first path connected to the one or more inlets, a second path connected to the outlet, a first branch path connecting the first path and the second path, and a second branch path connecting the first path and the second path so as not to pass through the first branch path, the first drive circuit being located in the first branch path and the second drive circuit being located in the second branch path.

[0006] A liquid injection device according to a preferred embodiment of the present invention is characterized by comprising a liquid injection head as described above and a gas supply mechanism that supplies gas to the one or more inlet portions of the liquid injection head. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram illustrating a liquid injection device 100 according to the first embodiment. [Figure 2] A perspective view of a liquid injection module 140 having a liquid injection head 10 according to an embodiment. [Figure 3] Figure 2 shows an exploded perspective view of the liquid injection head 10. [Figure 4] A schematic plan view showing the flow path of the head tip 14 of the liquid injection head 10. [Figure 5] A cross-sectional view of the head tip 14 of the liquid injection head 10. [Figure 6]A schematic diagram showing the path within the liquid injection head 10. [Figure 7] Exploded perspective view of the filter unit 11, head board 12, and holder unit 13. [Figure 8] Plan view of the liquid injection head 10. [Figure 9] A cross-sectional view showing section AA in Figure 8. [Figure 10] A bottom view of the liquid spray head 10 when the fixing plate 15 is not shown. [Figure 11] A cross-sectional view showing the BB cross-section in Figure 8. [Figure 12] Figure 8 shows the CC cross-section viewed in the V2 direction. [Figure 13] A cross-sectional view showing the DD section in Figure 8. [Figure 14] A plan view of the liquid spray head 10 when the filter plate Su1, protective case 16, and connector board 17 are not shown. [Figure 15] A plan view of the liquid injection head 10 when the filter plate Su2 is further omitted from the state shown in Figure 14. [Figure 16] A plan view of the liquid injection head 10 when the filter plate Su3 is further omitted from the state shown in Figure 15. [Figure 17] A schematic diagram showing the path within the liquid injection head 10-A according to the first modified example. [Figure 18] A schematic diagram showing the path within the liquid injection head 10-B according to the fifth modified example. [Modes for carrying out the invention]

[0008] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. Note that the dimensions and scale of the parts in the drawings differ from those of the actual parts as appropriate, and some parts are shown schematically for ease of understanding. Furthermore, the scope of the present invention is not limited to these embodiments unless otherwise stated in the following description.

[0009] In the following description, for convenience, the X-axis, Y-axis, and Z-axis that intersect each other are appropriately used. Also, one direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, the directions opposite to each other along the Y-axis are the Y1 direction and the Y2 direction. Further, the directions opposite to each other along the Z-axis are the Z1 direction and the Z2 direction.

[0010] 1. First Embodiment 1-1. Liquid Injection Device 100 FIG. 1 is a schematic diagram illustrating a liquid injection device 100 according to the first embodiment. The liquid injection device 100 is an inkjet printing device that injects ink, which is an example of a liquid, as droplets onto a medium M. The liquid injection device 100 of the present embodiment is a so-called line-type printing device in which a plurality of nozzles N for injecting ink are distributed over the entire range in the width direction of the medium M. The medium M is typically printing paper. Note that the medium M is not limited to printing paper, and may be a printing target of any material such as a resin film or a fabric, for example.

[0011] As shown in FIG. 1, the liquid injection device 100 includes a liquid container 110, a control unit 120, a conveyance mechanism 130, a liquid injection module 140, a circulation mechanism 150, and a gas supply mechanism 160.

[0012] The liquid container 110 is a container for storing ink. Specific examples of the liquid container 110 include, for example, a cartridge detachable from the liquid injection device 100, a bag-shaped ink pack formed of a flexible film, and an ink tank capable of replenishing ink. Note that the type of ink stored in the liquid container 110 is arbitrary.

[0013] Although not shown in the figure, the liquid container 110 of the present embodiment includes a first liquid container and a second liquid container. The first liquid container stores the first ink. The second liquid container stores a second ink of a type different from the first ink. For example, the first ink and the second ink are inks of different colors. Note that the first ink and the second ink may be of the same type.

[0014] The control unit 120 controls the operation of each element of the liquid injection device 100. The control unit 120 includes, for example, one or more processing circuits such as a CPU or FPGA, and one or more storage circuits such as semiconductor memory. CPU is an abbreviation for Central Processing Unit. FPGA is an abbreviation for Field Programmable Gate Array. Various programs and various data are stored in the storage circuits. The processing circuits realize various controls by executing the programs and using the data as appropriate.

[0015] The conveying mechanism 130 conveys the medium M in direction DM under the control of the control unit 120. In this embodiment, direction DM is the Y2 direction. In the example shown in Figure 1, the conveying mechanism 130 includes a long conveying roller along the X axis and a motor that rotates the conveying roller. The conveying mechanism 130 is not limited to a configuration using a conveying roller; for example, it may also use a drum or an endless belt that conveys the medium M while it is attracted to the outer surface by electrostatic force or the like.

[0016] The liquid injection module 140, under the control of the control unit 120, injects ink supplied from the liquid container 110 via the circulation mechanism 150 into the medium M from each of the multiple nozzles N in the Z2 direction. The Z2 direction is an example of the "injection direction". In this embodiment, the Z2 direction is the vertical direction. However, the Z2 direction and the vertical direction may be different. The liquid injection module 140 is a line head having multiple liquid injection heads 10 arranged so that the multiple nozzles N are distributed over the entire range of the medium M in the direction of the X axis. In other words, the collection of multiple liquid injection heads 10 constitutes a long line head extending in the direction along the X axis. Note that the multiple nozzles N of a single liquid injection head 10 may be arranged so that they are distributed over the entire range of the medium M in the direction along the X axis, in which case, for example, the liquid injection module 140 is composed of such a single liquid injection head 10.

[0017] A liquid container 110 is connected to the liquid injection module 140 via a circulation mechanism 150. The circulation mechanism 150, under the control of a control unit 120, supplies ink to the liquid injection module 140 and recovers the ink discharged from the liquid injection module 140 for resupply to the liquid injection module 140. The circulation mechanism 150 includes, for example, a sub-tank for storing ink, a flow path for supplying ink from the sub-tank to the liquid injection module 140, a flow path for recovering ink from the liquid injection module 140 to the sub-tank, and a pump for appropriately circulating the ink. These are provided for each of the first and second liquid containers described above. The operation of the circulation mechanism 150 as described above can suppress the increase in ink viscosity and reduce the retention of air bubbles in the ink.

[0018] The control unit 120 controls the spraying operation of the liquid spray head 10. Specifically, the control unit 120 receives image data Img representing an image from a host computer such as a personal computer or digital camera. Based on the received image data Img, the control unit 120 supplies a drive signal Com for driving the liquid spray head 10 and a control signal SI for controlling the liquid spray head 10 to the liquid spray head 10. The liquid spray head 10 is then driven by the drive signal Com under the control of the control signal SI, and sprays ink in the Z2 direction from some or all of the multiple nozzles N provided on the liquid spray head 10. That is, the liquid spray head 10 sprays ink from some or all of the multiple nozzles N in conjunction with the transport of the medium M by the transport mechanism 130, and the sprayed ink lands on the surface of the medium M, thereby forming a desired image on the surface of the medium M. The nozzles N will be described later in Figures 4 and 5.

[0019] The gas supply mechanism 160 is a mechanism for supplying gas to the liquid injection head 10, and more specifically, for cooling the drive circuit 18i, which will be described later. The gas supply mechanism 160 includes a gas storage section 162 for storing gas, a gas supply tube 164 for supplying the gas stored in the gas storage section 162, and a pump 166 for adjusting the amount of gas supplied.

[0020] The type of gas supplied by the gas supply mechanism 160 is not particularly limited, but it is preferable to use, for example, air, nitrogen, or an inert gas such as argon. Furthermore, the type of gas supplied by the gas supply mechanism 160 has a water vapor content of 4 g / m³. 3 Preferably, the following, and furthermore, 3 g / m 3 More preferably, the following is true: 1 g / m 3 The following would be most preferable.

[0021] The gas storage unit 162 is equipped with a control device for adjusting the temperature of the gas stored inside. The control device includes, for example, a temperature sensor for detecting the temperature of the gas in the gas storage unit 162, a cooling mechanism for cooling the temperature inside the gas storage unit 162, and a control device that drives the cooling mechanism to bring the temperature of the gas in the gas storage unit 162 to a desired temperature based on the temperature detected by the temperature sensor. However, the gas storage unit 162 does not necessarily have to have a control device.

[0022] The air supply tube 164 has multiple branching sections, each corresponding to the number of liquid spray heads 10. One end of the air supply tube 164 is connected to the gas storage section 162, and each end of the multiple branching sections is connected to each of the multiple liquid spray heads 10. The gas supply mechanism 160 is airtightly connected to the liquid spray heads 10 via the air supply tube 164 to prevent foreign matter such as ink mist or paper dust from entering the inside of the liquid spray heads 10.

[0023] The pump 166 is installed between the air supply tubes 164. Under the control of the control unit 120, the pump 166 adjusts the amount of gas supplied to the liquid injection head 10.

[0024] 1-2. Liquid injection module 140 Figure 2 is a perspective view of a liquid injection module 140 having liquid injection heads 10 according to an embodiment. As shown in Figure 2, the liquid injection module 140 has a support body 41 and a plurality of liquid injection heads 10. The support body 41 is a member that supports the plurality of liquid injection heads 10. In the example shown in Figure 2, the support body 41 is a plate-shaped member made of metal or the like, and is provided with mounting holes 41a for attaching the plurality of liquid injection heads 10. The plurality of liquid injection heads 10 are inserted into the mounting holes 41a in a direction aligned along the X axis, and each liquid injection head 10 is fixed to the support body 41 by screws or the like. In Figure 2, two liquid injection heads 10 are typically shown. The number of liquid injection heads 10 in the liquid injection module 140 is arbitrary. Also, the shape of the support body 41 is not limited to the example shown in Figure 2 and is arbitrary.

[0025] 1-3. Liquid spray head 10 Figure 3 is an exploded perspective view of the liquid spray head 10 shown in Figure 2. As shown in Figure 3, the liquid spray head 10 includes a filter unit 11, a head substrate 12, a holder unit 13, a plurality of head chips 14_1, 14_2, 14_3, 14_4, 14_5 and 14_6, a fixing plate 15, a protective case 16 and a connector substrate 17. These are arranged in the Z2 direction in the following order: connector substrate 17, protective case 16, filter unit 11, head substrate 12, holder unit 13, the plurality of head chips 14_1, 14_2, 14_3, 14_4, 14_5 and 14_6, and fixing plate 15. Each element of the liquid spray head 10 is fixed by adhesive or screws. The parts of the liquid spray head 10 will be described sequentially below. In the following, head chips 14_1, 14_2, 14_3, 14_4, 14_5 and 14_6 may each be referred to as head chip 14. In the first embodiment, the liquid injection head 10 has six head tips 14, but is not limited to six; it may have two or more.

[0026] In the following description, the components of the head chip 14_x may be represented by the subscript "_x" as a symbol to indicate the component. x is an integer from 1 to 6. The holder unit 13 is an example of a "first component". The filter unit 11 is an example of a "second component". The head board 12 is an example of a "first relay board". The connector board 17 is an example of a "second relay board". Head chips 14_1, 14_2, 14_3, 14_4, 14_5 and 14_6 are examples of "multiple head chips".

[0027] The filter unit 11 is a structure in which a flow path for flowing ink between the circulation mechanism 150 and the multiple head tips 14 is provided inside. The filter unit 11 has a filter plate Su1, a filter plate Su2, and a filter plate Su3. The filter plates Su3, Su2, and Su1 are stacked in this order in the Z1 direction. As shown in Figure 3, the surface Sa1 of the filter plate Su1 facing the Z1 direction is provided with connecting tubes 11a, 11b, 11c, 11d, a hole 11e, and a connecting tube 11f. Surface Sa1 is an example of a "first surface". By inserting the connecting tube 11f into the opening formed at the tip of the air supply tube 164, it is possible to suppress ink mist and paper dust floating in the liquid spray head 10 from entering the gas path AP in the liquid spray head 10, which will be described later.

[0028] Here, although not shown in Figure 3, the filter unit 11 has multiple flow channels for flowing ink and a part of a connecting section C1 which is part of the path for flowing gas supplied from the gas supply mechanism 160. The connecting section C1 will be described later in Figure 6. In this specification, the path through which ink flows is referred to as a "flow channel," and the path through which gas supplied from the gas supply mechanism 160 flows is referred to as a "path." The multiple flow channels for flowing ink inside the filter unit 11 are the first supply channel CC1, the second supply channel CC2, the first discharge channel CM1, and the second discharge channel CM2. The first supply channel CC1 is a flow channel for supplying the first ink to multiple head chips 14. The second supply channel CC2 is a flow channel for supplying the second ink to multiple head chips 14. Filters for capturing foreign matter are installed in the middle of each of these supply channels. The first discharge channel CM1 is a flow channel for discharging the first ink from the multiple head chips 14. The second discharge channel CM2 is a channel for discharging the second ink from multiple head chips 14. The channel and path of the filter unit 11 will be explained later based on Figures 7 and 15.

[0029] The connecting pipes 11a, 11b, 11c, 11d, and 11f are tubular bodies that protrude in the Z1 direction. More specifically, the connecting pipe 11a is a tubular body that constitutes a flow path for supplying the first ink to the first supply flow path CC1. The connecting pipe 11b is a tubular body that constitutes a flow path for supplying the second ink to the second supply flow path CC2. On the other hand, the connecting pipe 11c is a tubular body that constitutes a flow path for discharging the first ink from the first discharge flow path CM1. The connecting pipe 11d is a tubular body that constitutes a flow path for discharging the second ink from the second discharge flow path CM2. The connecting pipe 11f is a tubular body for introducing the gas supplied from the gas supply mechanism 160 into the inside of the liquid injection head 10. The hole 11e is a hole for inserting the connector 12a, which will be described later.

[0030] In the first embodiment, there is only one pipe, the connecting pipe 11f, through which the gas supplied from the gas supply mechanism 160 is introduced. However, the surface Sa1 may be provided with multiple pipes through which the gas supplied from the gas supply mechanism 160 is introduced. However, it is preferable that the number of pipes through which the gas supplied from the gas supply mechanism 160 is introduced is less than the number of head tips 14 that the liquid injection head 10 has. The opening of the connecting pipe 11f is an example of "one or more introduction parts". The openings of the connecting pipes 11a and 11b are examples of "liquid introduction parts for introducing liquid into the interior of the liquid injection head".

[0031] The head board 12 is a mounting component for electrically connecting multiple head chips 14 to the connector board 17 described later. The head board 12 is, for example, a rigid wiring board. The head board 12 is positioned between the filter unit 11 and the holder unit 13, and a connector 12a is installed on the surface of the head board 12 facing the filter unit 11. The connector 12a is a connecting component that is connected to the connector board 17 described later. The head board 12 is also provided with four holes 12b, four through holes 12c, two notches 12e, two notches 12f, a notch 12g, and a notch 12h. Each of the four holes 12b is a hole that allows connection between the filter unit 11 and the holder unit 13. Each of the two notches 12f, the notch 12g, and the notch 12h are also notches that allow connection between the filter unit 11 and the holder unit 13. Each of the four through-holes 12c is a hole into which a wiring board 18h ​​connecting the head chip 14 and the head substrate 12 is inserted. A wiring board 18h ​​is also inserted into the space formed by each of the two notches 12e. The liquid spray head 10 has four wiring boards 18h inserted into each of the four through-holes 12c, and two wiring boards 18h inserted into the space formed by each of the two notches 12e. Even when the wiring boards 18h are inserted into the through-holes 12c, the through-holes 12c are not blocked. These six wiring boards 18h are connected to the Z1-facing surface of the head substrate 12. The wiring boards 18h are components that include wiring that is electrically connected to the piezoelectric element 14e, which will be described later.

[0032] The holder unit 13 is a structure that accommodates and supports multiple head tips 14. The holder unit 13 is made of, for example, a resin material or a metal material. The holder unit 13 has a flow path plate Du1, a flow path plate Du2, and a holder Du3. The holder Du3, the flow path plate Du2, and the flow path plate Du1 are stacked in this order in the Z1 direction. The holder unit 13 is provided with six through holes 13e that penetrate along the Z axis. Furthermore, the surface of the flow path plate Du1 facing the Z1 direction is provided with connecting pipes 13a, 13b, three connecting pipes 13c, three connecting pipes 13d, and 13f. The holder Du3 is provided with a flange Du3a for fixing the liquid injection head 10 to the support 41. In addition, although not shown, the surface of the holder unit 13 facing the Z2 direction is provided with multiple recesses for accommodating multiple head tips 14.

[0033] In this embodiment, the holder unit 13 holds six head tips 14_1 to 14_6. These head tips 14 are arranged in the X2 direction in the order of head tips 14_1, 14_4, 14_2, 14_5, 14_3, and 14_6. Here, head tips 14_1 to 14_3 are positioned offset in the Y1 direction relative to head tips 14_4 to 14_6. However, head tips 14_1 to 14_6 have overlapping portions when viewed in the X1 or X2 direction. Furthermore, the arrangement direction DN of the multiple nozzles N of head tips 14_1 to 14_6, which will be described later, are parallel to each other. In addition, each of the head tips 14_1 to 14_6 is arranged such that its arrangement direction DN is inclined with respect to the direction DM, which is the transport direction of the medium M.

[0034] Here, although not shown in the diagram, the holder unit 13 is provided with a first distribution and supply channel, a second distribution and supply channel, a plurality of first individual discharge channels, a plurality of second individual discharge channels, a plurality of bypass channels BP, and a part of the path for flowing gas from the gas supply mechanism 160. The first distribution and supply channel is a channel with branches for supplying first ink to a plurality of head chips 14. The second distribution and supply channel is a channel with branches for supplying second ink to a plurality of head chips 14. The first individual discharge channel is provided for each head chip 14 that discharges first ink and is a channel for introducing the first ink discharged from the head chip 14 into the first discharge channel CM1 of the filter unit 11. The second individual discharge channel is provided for each head chip 14 that discharges second ink and is a channel for introducing the second ink discharged from the head chip 14 into the second discharge channel CM2 of the filter unit 11. Two bypass channels BP are provided for each head tip 14, and they are bypass channels that connect the first common liquid chamber R1 and the second common liquid chamber R2, which will be described later. The path of the holder unit 13 will be explained based on Figures 7, 11, and 12, which will be described later.

[0035] The connecting tubes 13a, 13b, 13c, 13d, and 13f are tubular projections that protrude from the surface Sa1 in the Z1 direction. More specifically, the connecting tube 13a is a tube that constitutes a channel for supplying the first ink to the first distribution supply channel of the holder unit 13 and communicates with the first supply channel CC1 of the filter unit 11. The connecting tube 13b is a tube that constitutes a channel for supplying the second ink to the second distribution supply channel of the holder unit 13 and communicates with the second supply channel CC2 of the filter unit 11. On the other hand, the connecting tube 13c is a tube that constitutes a channel for discharging the first ink from the first individual discharge channel and communicates with the first discharge channel CM1 of the filter unit 11. The connecting tube 13d is a tube that constitutes a channel for discharging the second ink from the second individual discharge channel and communicates with the second discharge channel of the filter unit 11. The through hole 13e is into which the wiring board 18h ​​connecting the head chip 14 and the head substrate 12 is inserted. Even when the wiring board 18h ​​is inserted into the through-hole 13e, the through-hole 13e is not blocked. The connecting pipe 13f is a pipe that constitutes a path for supplying gas to the communication section C1 and communicates with the communication section C1 of the filter unit 11.

[0036] Each head tip 14 ejects ink. Specifically, although not shown in Figure 3, each head tip 14 has multiple nozzles N that eject either the first ink or the second ink. These nozzles N are provided on the nozzle surface FN, which is the surface of each head tip 14 facing the Z2 direction. Details of the head tip 14 will be explained later based on Figure 4.

[0037] The fixing plate 15 is a plate member for fixing multiple head chips 14 to the holder unit 13. Specifically, the fixing plate 15 is positioned between the holder unit 13 and the multiple head chips 14, and is fixed to the holder unit 13 with adhesive. The fixing plate 15 is made of, for example, a metal material. The fixing plate 15 is provided with multiple openings 15a for exposing the nozzles N of the multiple head chips 14. In the example shown in Figure 3, the multiple openings 15a are provided individually for each head chip 14.

[0038] The protective case 16 is a component that protects the connector substrate 17 and fixes the connector substrate 17 to the filter unit 11. The protective case 16 is made of, for example, a resin material. The protective case 16 has a component 16a and a component 16b. Component 16a is a substantially flat plate component that extends in the XZ plane. Near each of the four vertices of component 16a, there are claws 16c that extend in the Y1 direction for attachment to component 16b. Furthermore, component 16a is provided with a pressing component 16d for pressing the connector substrate 17. When component 16a is attached to component 16b, a through hole 16h is formed in the protective case 16 that penetrates the protective case 16 along the Z axis.

[0039] Member 16b is a substantially rectangular parallelepiped having an opening that penetrates the Z-axis. A notch 16e is provided on the face of member 16b facing the Y2 direction for attaching member 16a. Furthermore, notches 16f are provided on the sides of member 16b in the X1 and X2 directions for inserting two of the four claws 16c of member 16a that are located in the Z2 direction. In addition, member 16b is provided with a flange 16g for fixing to the filter unit 11. The protective case 16 and the filter unit 11 are fixed together by inserting and screwing screws into holes (not shown) formed in the flange 16g and screw holes (not shown) formed in the surface Sa1 of the filter unit 11.

[0040] The connector board 17 is a mounting component for electrically connecting the control unit 120 and the aforementioned head board 12. The connector board 17 is, for example, a rigid wiring board. The connector board 17 is inserted into the through hole 16h. Even when the connector board 17 is inserted into the through hole 16h, the through hole 16h is not closed. On the X1 and X2 sides of the connector board 17, notches 17a are provided into which two of the four claws 16c of member 16a, located in the Z1 direction, are inserted. Furthermore, connectors 17b for connecting to the control unit 120 are provided at the Z1 end of the face of the connector board 17 facing the Y1 direction, and at the Z1 end of the face of the face facing the Y2 direction. In addition, a connector 17c that connects to connector 12a is provided at the Z2 end of the face of the connector board 17 facing the Y1 direction.

[0041] 1-4. Head tip 14 Figure 4 is a schematic plan view showing the flow path of the head tip 14 of the liquid injection head 10. For convenience, the following explanation will use the V axis and W axis as appropriate, in addition to the X, Y, and Z axes. The direction along the V axis is the V1 direction, and the direction opposite to the V1 direction is the V2 direction. Similarly, the directions along the W axis that are opposite to each other are the W1 direction and the W2 direction.

[0042] Here, the V-axis is an axis along the arrangement direction DN of the multiple nozzles N described later, and is the axis obtained by rotating the Y-axis around the Z-axis by a predetermined angle. The W-axis is the axis obtained by rotating the X-axis around the Z-axis by the same predetermined angle. Therefore, the V-axis and W-axis are typically orthogonal to each other, but are not limited to this, and may intersect at an angle within the range of 80° to 100°. Furthermore, the predetermined angle, i.e., the angle between the V-axis and the Y-axis, or the angle between the W-axis and the X-axis, is, for example, within the range of 40° to 60°.

[0043] As shown in Figure 4, the head tip 14 is provided with multiple nozzles N, multiple individual flow channels PJ, a first common liquid chamber R1, and a second common liquid chamber R2. Here, the first common liquid chamber R1 and the second common liquid chamber R2 are connected via multiple individual flow channels PJ. Also, as shown by the dashed lines in Figure 4, bypass flow channels BP1 and BP2 are connected to the first common liquid chamber R1 and the second common liquid chamber R2. Hereinafter, bypass flow channels BP1 and BP2 may be collectively referred to as "bypass flow channels BP". Bypass flow channels BP1 and BP2 are flow channels that bypass multiple individual flow channels PJ to connect the first common liquid chamber R1 and the second common liquid chamber R2, and are provided in the holder unit 13.

[0044] The print head 14 has a surface facing the medium M, and as shown in Figure 4, a plurality of nozzles N are provided on this surface. The plurality of nozzles N are arranged along the V axis. Each of the plurality of nozzles N ejects ink in the Z2 direction.

[0045] Here, a collection of multiple nozzles N constitutes a nozzle array Ln. Furthermore, the multiple nozzles N are arranged at equal intervals with a predetermined pitch. This predetermined pitch is the distance between the centers of the multiple nozzles N in the direction along the V-axis.

[0046] Each of the multiple nozzles N is connected to an individual channel PJ. Each of the multiple individual channel PJs extends along the W axis and connects to a different nozzle N. The multiple individual channel PJs are arranged along the V axis.

[0047] As shown in Figure 4, each individual channel PJ has a pressure chamber Ca, a pressure chamber Cb, a nozzle channel Nf, an individual supply channel Ra1, an individual discharge channel Ra2, a first connecting channel Na1, and a second connecting channel Na2.

[0048] Each pressure chamber Ca and pressure chamber Cb in each individual flow path PJ extends along the W axis and is a space where ink ejected from a nozzle N communicating with the individual flow path PJ is stored. In the example shown in Figure 4, multiple pressure chambers Ca are arranged along the V axis. Similarly, multiple pressure chambers Cb are arranged along the V axis. In the example shown in Figure 4, the positions of pressure chambers Ca and pressure chamber Cb along the V axis are the same, but they may be different. In the following, when pressure chambers Ca and pressure chamber Cb are not specifically distinguished, they may each be referred to as "pressure chamber C".

[0049] A nozzle channel Nf is positioned between the pressure chamber Ca and the pressure chamber Cb in each individual channel PJ. Here, pressure chamber Ca communicates with nozzle channel Nf via a first communication channel Na1 extending along the Z-axis. Pressure chamber Cb communicates with nozzle channel Nf via a second communication channel Na2 extending along the Z-axis.

[0050] In each individual flow path PJ, the nozzle flow path Nf is a space extending along the W axis. Multiple nozzle flow paths Nf are arranged along the V axis with intervals between them. Each nozzle flow path Nf is provided with a nozzle N. In each nozzle flow path Nf, ink is ejected from the nozzle N as the pressure in the aforementioned pressure chambers Ca and Cb changes.

[0051] The first communication channel Na1 and the second communication channel Na2 are spaces that extend along the Z-axis. The first communication channel Na1 and the second communication channel Na2 may be provided as needed, or they may be omitted.

[0052] Multiple individual flow channels PJ are connected to a first common liquid chamber R1 and a second common liquid chamber R2. Here, pressure chamber Ca is connected to the first common liquid chamber R1 via an individual supply flow channel Ra1 extending along the Z-axis. Pressure chamber Cb is connected to the second common liquid chamber R2 via an individual discharge flow channel Ra2 extending along the Z-axis.

[0053] The first common liquid chamber R1 and the second common liquid chamber R2 are spaces that extend along the V-axis over the entire area where multiple nozzles N are distributed. Here, the first common liquid chamber R1 is connected to the end of each individual flow path PJ in the W2 direction. The first common liquid chamber R1 stores ink for supply to each individual flow path PJ. On the other hand, the second common liquid chamber R2 is connected to the end of each individual flow path PJ in the W1 direction. The second common liquid chamber R2 stores ink that is discharged from each individual flow path PJ without being used for ejection.

[0054] The first common liquid chamber R1 is provided with a supply port IO1, an outlet port IO3a, and an outlet port IO3b. The supply port IO1 is a conduit for introducing ink from the distribution supply channel SP of the holder unit 13 into the first common liquid chamber R1. The outlet port IO3a is a conduit for discharging ink from the first common liquid chamber R1 to the bypass channel BP1. The outlet port IO3b is a conduit for discharging ink from the first common liquid chamber R1 to the bypass channel BP2.

[0055] Here, the distribution supply channel SP is connected to the circulation mechanism 150 via the supply channel CC of the filter unit 11. Therefore, the channel from the connecting pipe 11a or connecting pipe 11b to the first common liquid chamber R1 is provided in common for multiple pressure chambers C, and constitutes a common supply channel CF1 that supplies ink to multiple individual channels PJ. The supply channel CC is the first supply channel CC1 or the second supply channel CC2, which will be described later. In addition, although not shown in Figure 4, the common supply channel CF1 also includes the first common liquid chamber R1, the distribution supply channel SP, and the supply channel CC, as well as the first filter chamber RF1 or the second filter chamber RF2, which will be described later.

[0056] The second common liquid chamber R2 is provided with an outlet IO2, an inlet IO4a, and an inlet IO4b. Outlet IO2 is a conduit for discharging ink from the second common liquid chamber R2 to the individual discharge channel DS of the holder unit 13. Inlet IO4a is a conduit for introducing ink from the bypass channel BP1 to the second common liquid chamber R2. Inlet IO4b is a conduit for introducing ink from the bypass channel BP2 to the second common liquid chamber R2.

[0057] Here, the individual discharge channel DS is connected to the circulation mechanism 150 via the discharge channel CM of the filter unit 11. Therefore, the flow path from the second common liquid chamber R2 to the connecting pipe 11a or connecting pipe 11b is provided in common for multiple pressure chambers C, and constitutes a common discharge channel CF2 that discharges ink from multiple individual channels PJ. The discharge channel CM is either the first discharge channel CM1 or the second discharge channel CM2, which will be described later.

[0058] Figure 5 is a cross-sectional view of the head tip 14 of the liquid injection head 10. In Figure 5, in addition to the head tip 14, the wiring board 18h ​​is also shown. Figure 5 shows a cross-section of the head tip 14 cut in a plane including the W axis and Z axis. As shown in Figure 5, the head tip 14 has a nozzle substrate 14a, a flow path substrate 14b, a pressure chamber substrate 14c, a diaphragm 14d, a plurality of piezoelectric elements 14e, a case 14f, and a protective plate 14g.

[0059] The nozzle substrate 14a, the flow channel substrate 14b, the pressure chamber substrate 14c, and the diaphragm 14d are stacked in this order in the Z1 direction. Each of these components extends along the V axis and is manufactured, for example, by processing a silicon single crystal substrate using semiconductor processing technology. These components are joined to each other by adhesive or the like. A layer or substrate, such as an adhesive layer, may be appropriately interposed between two adjacent components.

[0060] Multiple nozzles N are provided on the nozzle substrate 14a. Each of the multiple nozzles N penetrates the nozzle substrate 14a and is a through-hole through which ink passes. The multiple nozzles N are arranged in a direction along the V-axis.

[0061] The flow channel substrate 14b is provided with a portion of the first common liquid chamber R1 and the second common liquid chamber R2, and the portions of the multiple individual flow channels PJ excluding the pressure chamber Ca and pressure chamber Cb. Specifically, the flow channel substrate 14b is provided with a nozzle flow channel Nf, a first connecting flow channel Na1, a second connecting flow channel Na2, an individual supply flow channel Ra1, and an individual discharge flow channel Ra2.

[0062] Parts of the first common liquid chamber R1 and the second common liquid chamber R2 are spaces that penetrate the flow channel substrate 14b. A vibration absorber 14j is installed on the surface of the flow channel substrate 14b facing the Z2 direction to close the opening created by these spaces.

[0063] The vibration absorber 14j is a layered member made of an elastic material. The vibration absorber 14j constitutes a part of the wall surface of the first common liquid chamber R1 and the second common liquid chamber R2, and absorbs pressure fluctuations in the first common liquid chamber R1 and the second common liquid chamber R2.

[0064] The nozzle channel Nf is a space within a groove provided on the surface of the channel substrate 14b facing the Z2 direction. Here, the nozzle substrate 14a constitutes a part of the wall surface of the nozzle channel Nf.

[0065] The first communication channel Na1 and the second communication channel Na2 are spaces that penetrate the channel substrate 14b, respectively.

[0066] Each of the individual supply channel Ra1 and individual discharge channel Ra2 is a space that penetrates the channel substrate 14b. The individual supply channel Ra1 connects the first common liquid chamber R1 and the pressure chamber Ca, and supplies ink from the first common liquid chamber R1 to the pressure chamber Ca. Here, one end of the individual supply channel Ra1 opens to the surface of the channel substrate 14b facing in the Z1 direction. On the other hand, the other end of the individual supply channel Ra1 is the upstream end of the individual channel PJ, and opens to the wall surface of the first common liquid chamber R1 in the channel substrate 14b. In contrast, the individual discharge channel Ra2 connects the second common liquid chamber R2 and the pressure chamber Cb, and discharges ink from the pressure chamber Cb to the second common liquid chamber R2. Here, one end of the individual discharge channel Ra2 opens to the surface of the channel substrate 14b facing in the Z1 direction. On the other hand, the other end of the individual discharge channel Ra2 is the downstream end of the individual channel PJ and opens to the wall surface of the second common liquid chamber R2 in the channel substrate 14b.

[0067] The pressure chamber substrate 14c is provided with multiple individual flow channels PJ, each containing pressure chambers Ca and Cb. Each of the pressure chambers Ca and Cb penetrates the pressure chamber substrate 14c and forms a gap between the flow channel substrate 14b and the diaphragm 14d.

[0068] The diaphragm 14d is an elastically vibrating plate-shaped member. The diaphragm 14d is a laminate comprising, for example, a first layer made of silicon oxide (SiO2) and a second layer made of zirconium oxide (ZrO2). Here, other layers, such as metal oxides, may be interposed between the first and second layers. Part or all of the diaphragm 14d may be integrally formed from the same material as the pressure chamber substrate 14c. For example, the diaphragm 14d and the pressure chamber substrate 14c can be integrally formed by selectively removing a portion in the thickness direction of the region corresponding to the pressure chamber C in a plate-shaped member of a predetermined thickness. Alternatively, the diaphragm 14d may be composed of layers of a single material.

[0069] Multiple piezoelectric elements 14e, corresponding to different pressure chambers C, are installed on the surface of the diaphragm 14d facing the Z1 direction. Each piezoelectric element 14e is composed of, for example, a stack of a first electrode and a second electrode facing each other and a piezoelectric layer placed between the two electrodes. Each piezoelectric element 14e causes the ink in the pressure chamber C to be ejected from the nozzle N by fluctuating the pressure of the ink in the pressure chamber C. When a drive signal Com is supplied, the piezoelectric element 14e vibrates the diaphragm 14d as it deforms. As a result of this vibration, the pressure chamber C expands and contracts, causing the pressure of the ink in the pressure chamber C to fluctuate. Note that the piezoelectric element 14e is an example of a "drive element". However, the head chip 14 may have a heating element instead of the piezoelectric elements 14e.

[0070] Case 14f is a case for storing ink. Case 14f is provided with spaces that constitute the remaining portion of the first common liquid chamber R1 and the second common liquid chamber R2, excluding a portion provided on the flow path substrate 14b. The drive circuit 18i is located outside case 14f.

[0071] The protective plate 14g is a plate-shaped member installed on the surface of the diaphragm 14d facing the Z1 direction, protecting the multiple piezoelectric elements 14e and reinforcing the mechanical strength of the diaphragm 14d. Here, a space for accommodating the multiple piezoelectric elements 14e is formed between the protective plate 14g and the diaphragm 14d.

[0072] The wiring board 18h ​​is mounted on the Z1-facing side of the diaphragm 14d and is a mounting component for electrically connecting the control unit 120 and the head chip 14. The wiring board 18h ​​is made of a flexible circuit board such as an FPC. If the wiring board 18h ​​is an FPC, it forms a COF together with the drive circuit 18i. FPC is an abbreviation for Flexible Printed Circuits. COF is an abbreviation for Chip On Film. The drive circuit 18i for driving the head chip 14 is mounted on the wiring board 18h.

[0073] The drive circuit 18i is an integrated circuit that includes a switching element capable of selecting whether or not to supply a drive signal Com to drive the piezoelectric element 14e for ejecting ink. Specifically, this switching element selects to supply the drive signal Com to the piezoelectric element 14e if the control signal SI supplied from the control unit 120 is a signal instructing the piezoelectric element 14e to be driven. Conversely, this switching element selects not to supply the drive signal Com to the piezoelectric element 14e if the control signal SI supplied from the control unit 120 is a signal instructing the piezoelectric element 14e not to be driven.

[0074] In the head tip 14 with the above configuration, the operation of the aforementioned circulation mechanism 150 causes the ink to flow in the following order: first common liquid chamber R1, individual supply channel Ra1, pressure chamber Ca, nozzle channel Nf, pressure chamber Cb, individual discharge channel Ra2, and second common liquid chamber R2.

[0075] Furthermore, the drive signal Com from the drive circuit 18i simultaneously drives the piezoelectric element 14e corresponding to both pressure chamber Ca and pressure chamber Cb, thereby fluctuating the pressure in pressure chamber Ca and pressure chamber Cb, and ink is ejected from the nozzle N in accordance with this pressure fluctuation.

[0076] 1-5. Path within the liquid injection head 10 Figure 6 is a schematic diagram showing the path within the liquid injection head 10. In Figure 6, the positional relationship of each element in the direction perpendicular to the Z-axis and the orientation of each element have been appropriately changed to facilitate the explanation of the path, and therefore differ from the original positional relationship and orientation of each element.

[0077] The liquid injection head 10 has a gas path AP. The gas path AP is the path through which the gas supplied from the gas supply mechanism 160 flows, from the inlet Pin, which is the opening of the connecting pipe 11f, to the outlet Pout, which is the opening of the protective case 16. As mentioned above, the connecting pipe 11f is provided on the surface Sa1. Since the connecting pipe 11f provided on the surface Sa1 defines the inlet Pin, it can be said that the inlet Pin is also provided on the surface Sa1. The outlet Pout is a wiring opening formed in the outer wall of the liquid injection head 10. Figure 6 shows the gas flows FRa, FRb, and FRc inside the liquid injection head 10. The fact that the introduction portion Pin is provided on surface Sa1 is an example of "one or more introduction portions are provided on the first surface of the second member." "One or more introduction portions are provided on the first surface of the second member" includes not only the configuration in which the introduction portion is directly provided on the first surface of the second member, but also the configuration in which a member defining the introduction portion is provided on the first surface of the second member, as in this embodiment.

[0078] Gas supplied from the gas supply mechanism 160 is introduced into the inlet Pin. The discharge section Pout discharges the gas to the outside of the liquid injection head 10 in the Z1 direction.

[0079] The gas path AP has a supply path PT1 connected to the introduction pin, a discharge path PT2 connected to the discharge section Pout, and a number of branch paths BT equal to the number of head chips 14. In the first embodiment, the gas path AP has a branch path BT_1 corresponding to head chip 14_1, a branch path BT_2 corresponding to head chip 14_2, a branch path BT_3 corresponding to head chip 14_3, a branch path BT_4 corresponding to head chip 14_4, a branch path BT_5 corresponding to head chip 14_5, and a branch path BT_6 corresponding to head chip 14_6. Hereinafter, each of the branch paths BT_1, BT_2, BT_3, BT_4, BT_5, and BT_6 may be referred to as branch path BT. The branch path BT corresponding to a head chip 14 means the branch path BT among branch paths BT_1, BT_2, BT_3, BT_4, BT_5, and BT_6 into which the wiring board 18h ​​connected to the head chip 14 is inserted. Each of the six branch paths BT is equipped with a drive circuit 18i for driving the corresponding head chip 14.

[0080] In the first embodiment, the six branch paths BT correspond one-to-one with the six head chips 14, but this is not limited to this configuration. For example, two wiring boards 18h, each connected to a multiple, for example, two head chips 14, may be inserted into one of the multiple branch paths BT. In other words, if there are six head chips 14 and two wiring boards 18h corresponding to one branch path BT, then three branch paths BT will be provided.

[0081] The branch paths BT are formed by through holes provided in the flow path plate Du1, flow path plate Du2, and holder Du3 that form the holder unit 13. Each of the six branch paths BT connects the supply path PT1 and the discharge path PT2 without passing through other branch paths BT. However, there may be small gaps between flow path plate Du1 and flow path plate Du2, and between flow path plate Du2 and holder Du3. In other words, adjacent branch paths BT may be connected by the space between flow path plate Du1 and flow path plate Du2, and the space between flow path plate Du2 and holder Du3. If the gap is narrow, the amount of gas flowing from one adjacent branch path BT to the other through the gap is very small. Therefore, even if there is a small gap between the flow path plate Du1 and the flow path plate Du2, and between the flow path plate Du2 and the holder Du3, it can be considered that "each of the six branch paths BT connects the supply path PT1 and the discharge path PT2 without passing through other branch paths BT."

[0082] Here, in order to efficiently cool the drive circuit 18i, it is preferable that the inside of the liquid injection head 10 is sealed. In other words, it is preferable that all of the gas supplied from the inlet Pin is discharged from the outlet Pout, and it is undesirable for it to be discharged from any opening other than the outlet Pout. Therefore, it is preferable that no gaps are created in the outer wall of the liquid injection head 10 between the fixing plate 15 and the holder unit 13, between the holder unit 13 and the filter unit 11, between the filter unit 11 and the protective case 16, between the filter plate Su1 and the filter plate Su2, between the filter plate Su2 and the filter plate Su3, between the flow path plate Du1 and the flow path plate Du2, and between the flow path plate Du2 and the holder Du3, by using adhesive or the like.

[0083] The supply path PT1 is an example of the "first path". The discharge path PT2 is an example of the "second path". Of the head chips 14_1, 14_2, 14_3, 14_4, 14_5, and 14_6, head chip 14_x is an example of the "first head chip", head chip 14_y is an example of the "second head chip", and head chip 14_z is an example of the "third head chip". x, y, and z are integers from 1 to 6, and each has a different value. Furthermore, of the branch paths BT_1, BT_2, BT_3, BT_4, BT_5, and BT_6, branch path BT_x is an example of the "first branch path", branch path BT_y is an example of the "second branch path", and branch path BT_z is an example of the "third branch path". The drive circuit 18i_x for driving head chip 14_x is an example of the "first drive circuit". The drive circuit 18i_y for driving the head chip 14_y is an example of a "second drive circuit". The drive circuit 18i_z for driving the head chip 14_z is an example of a "third drive circuit". The wiring board 18h_x connected to the head chip 14_x is an example of a "first wiring board". The wiring board 18h_y connected to the head chip 14_y is an example of a "second wiring board".

[0084] As shown in Figure 6, the supply path PT1 includes a first housing space S1 that accommodates six head chips 14, and a communication section C1 that connects the introduction section Pin to the first housing space S1. Each of the six branch paths BT is connected to the first housing space S1. The first housing space S1 is a space partitioned by the surface of the holder unit 13 and the surface of the fixing plate 15 facing the Z1 direction. Although not shown in Figure 6, the communication section C1 includes a portion that extends in a direction perpendicular to the Z axis. Details of the communication section C1 will be described later using Figures 7 to 9.

[0085] The discharge path PT2 has a second housing space S2 that houses the head board 12, a hole 11e, and a through hole 16h. The second housing space S2 is a space partitioned by the surface of the filter unit 11 and the surface of the holder unit 13. Six branch paths BT are connected to the second housing space S2. The holder unit 13 can also be said to be positioned between the first housing space S1 and the second housing space S2. As shown in Figure 3, the holder unit 13 has six through holes 13e. Each of these six through holes 13e is a branch path BT. When the head chip 14_1 corresponds to the "first head chip," the through hole 13e into which the wiring board 18h ​​connected to the head chip 14_1 is inserted is an example of the "first through hole." When the head chip 14_2 corresponds to the "second head chip," the through hole 13e into which the wiring board 18h ​​connected to the head chip 14_2 is inserted is an example of the "second through hole."

[0086] The gas supplied from the gas supply mechanism 160 is introduced into the first containment space S1 via the introduction section Pin and the communication section C1, as shown by flow FRa. Flow FRa is indicated by a white arrow. In the following diagram, the white arrows represent the flow of the gas before it is heated by the drive circuit 18i. The gas introduced into the first containment space S1 reaches the second containment space S2 via one of the branch paths BT_1 to BT_6, as shown by flow FRb. As the gas passes through the branch path BT, it is blown onto the drive circuit 18i, and heat exchange takes place between the drive circuit 18i, which is located within the branch path BT, and the gas. That is, the drive circuit 18i is cooled by the gas, and the gas is heated by the drive circuit 18i. Flow FRb is the flow from the Z2 direction to the Z1 direction. Flow FRb is indicated by an arrow that changes from white to shaded. The arrows that change from white to shaded indicate that the gas is heated by the drive circuit 18i during the flow. The heated gas is discharged in the Z1 direction from the second containment space S2 through the hole 11e, the through hole 16h, and the discharge section Pout, as shown by the flow FRc. The flow FRc is indicated by the shaded arrows. The shaded arrows indicate the flow of the gas after it has been heated by the drive circuit 18i.

[0087] In Figure 6, an example is shown in which all of the heated gas moves in a direction perpendicular to the Z axis at a position in the Z1 direction relative to the head substrate 12, and moves in the space close to the introduction pin with respect to the connector substrate 17 at each of the holes 11e, through holes 16h, and discharge section Pout, but this is not limited to this example. Specifically, a portion of the heated gas may move in a direction perpendicular to the Z axis at a position in the Z2 direction relative to the head substrate 12, and move in the space farther from the introduction pin with respect to the connector substrate 17 at each of the holes 11e, through holes 16h, and discharge section Pout.

[0088] 1-6.Communication part C1 The shape of the communication section C1 will be explained using Figures 7 to 9. Figure 7 is an exploded perspective view of the filter unit 11, head board 12, and holder unit 13. However, in Figure 7, shapes other than the communication section C1 have been omitted as appropriate to avoid complexity in the drawing. Figure 8 is a plan view of the liquid injection head 10. The plan view shown in Figure 8 can also be said to be a plan view of the liquid injection head 10 seen in the Z2 direction. Hereafter, the plan view seen in the Z2 direction will be simply referred to as "plan view". Figure 9 is a cross-sectional view showing the AA section of Figure 8. The AA section passes through the connecting pipe 11f and is parallel to the X and Z axes. Also, in Figure 9, the cross-sections of the head tips 14_4, 14_5, and 14_6 are omitted to avoid complexity in the drawing. Figure 9 shows the gas flow FRa1 flowing from the introduction section Pin to the first containment space S1. Flow FRa1 is a portion of the flow FRa shown in Figure 6.

[0089] As shown in Figures 7 and 9, the communication section C1 is located on the inside of the outer wall of the liquid injection head 10 in the Y2 direction. As shown in Figures 7 and 9, the communication section C1 has a connecting pipe section C10, a first vertical section C11, a horizontal section C12, and a second vertical section C13. The connecting pipe section C10, the first vertical section C11, and the second vertical section C13 extend along the Z axis. The connecting pipe section C10 is the internal space of the connecting pipe 11f and communicates with the inlet section Pin, which is the opening of the connecting pipe 11f. The Z1 end of the first vertical section C11 communicates with the connecting pipe section C10. The Z2 end of the first vertical section C11 communicates with the X1 end of the horizontal section C12. The first vertical section C11 is an opening along the Z axis of the filter plate Su2.

[0090] As shown in Figure 7, the openings of the connecting tubes 11a and 11b are liquid introduction sections Lin for introducing ink into the liquid spray head 10. As described above, the connecting pipes 11a and 11b are provided on surface Sa1. Since the connecting pipes 11a and 11b provided on surface Sa1 define the liquid introduction section Lin, it can be said that the liquid introduction section Lin is also provided on surface Sa1. The provision of the liquid introduction section Lin on surface Sa1 is an example of "the first surface of the second member is provided with a liquid introduction section for introducing liquid into the liquid spray head." The provision "the first surface of the second member is provided with a liquid introduction section for introducing liquid into the liquid spray head" includes not only the configuration in which the liquid introduction section is directly provided on the first surface of the second member, but also the configuration in which a member defining the liquid introduction section is provided on the first surface of the second member, as in this embodiment.

[0091] As shown in Figures 7 and 9, the surface of the filter plate Su2 facing the Z1 direction has a recess that is recessed in the Z2 direction, and this recess forms the bottom Su2a. A connecting pipe Su21 is formed on the bottom Su2a, protruding in the Z1 direction. The connecting pipe Su21 is provided with a through hole that penetrates the filter plate Su2. The through hole provided in the connecting pipe Su21 is the first vertical portion C11.

[0092] The horizontal portion C12 extends along the X-axis. The X-axis is an example of a "direction perpendicular to the injection direction." Therefore, the horizontal portion C12 may extend in a direction perpendicular to the Z-axis, or it may extend in a direction intersecting the X-axis. One end of the horizontal portion C12 in the X2 direction is connected to the second vertical portion C13. The horizontal portion C12 is also an example of a "portion extending in a direction perpendicular to the injection direction" of the communication portion C1. In this embodiment, the horizontal portion C12 extends along the horizontal direction because the Z2 direction is the vertical direction. However, if the Z2 direction, or more precisely the Z-axis, intersects the vertical direction, the horizontal portion C12 may extend in a direction different from the horizontal direction. The same applies to the connecting pipe section C10, the first vertical section C11, and the second vertical section C13. When the Z2 direction, or more precisely the Z axis, intersects the vertical direction, the connecting pipe section C10, the first vertical section C11, and the second vertical section C13 may extend in a direction that intersects the direction perpendicular to the horizontal plane.

[0093] As shown in Figures 7 and 9, the horizontal portion C12 is formed from the surface of the filter plate Su3 and the filter plate Su2. As shown in Figures 7 and 9, the surface of the filter plate Su3 facing in the Z1 direction has a recess that is recessed in the Z2 direction, and this recess forms the bottom portion Su3a. The wall Su32 of the horizontal portion C12 that protrudes in the Z1 direction is formed on the bottom portion Su3a. Also, as shown in Figures 7 and 9, the surface of the filter plate Su2 facing in the Z2 direction has a recess that is recessed in the Z1 direction, and this recess forms the bottom portion Su2b. The wall Su22 of the horizontal portion C12 that protrudes in the Z2 direction is formed on the bottom portion Su2b. The horizontal portion C12 is formed by bonding the surface of the wall Su22 facing in the Z2 direction and the surface of the wall Su32 facing in the Z1 direction.

[0094] The second vertical section C13 has sections C31, C32, C33, and C34. As shown in Figures 7 and 9, the Z1-direction end of section C31 communicates with the X2-direction end of the horizontal section C12. The Z2-direction end of section C31 communicates with the Z1-direction end of section C32. As shown in Figures 7 and 9, the Z2-direction surface of the filter plate Su3 has a recess that is recessed in the Z1 direction, and this recess forms the bottom section Su3b. A connecting pipe Su31 protruding in the Z2 direction is formed in the bottom section Su2a. The connecting pipe Su31 is provided with a through hole that penetrates the filter plate Su3 and communicates with the horizontal section C12. The through hole provided in the connecting pipe Su31 is section C31.

[0095] As shown in Figures 7 and 9, the Z2-direction end of section C32 communicates with the Z1-direction end of section C33. As shown in Figures 7 and 9, the Z1-direction-facing surface of the flow path plate Du1 has a recess that is indented in the Z2 direction, and this recess forms the bottom section Du1a. ​​A connecting pipe 13f protruding in the Z1 direction is formed in the bottom section Du1a. ​​The connecting pipe 13f is provided with a through hole that penetrates the flow path plate Du1. The through hole in the connecting pipe 13f is section C32. The connecting pipe 13f connects to section C31 by passing through the space formed by the notch 12g.

[0096] As shown in Figures 7 and 9, the Z2 end of section C33 communicates with the Z1 end of section C34. The flow path plate Du2 is provided with a through hole that penetrates the flow path plate Du2. This through hole is section C33.

[0097] As shown in Figure 9, the surface of holder Du3 facing the Z2 direction has a recess that is recessed in the Z1 direction to accommodate six head tips 14. The space formed by this recess is the first storage space S1. Part C34 is the Z1 direction end of the communication part C1. The Z2 direction end of part C34 communicates with the first storage space S1. The first storage space S1 will be explained with reference to Figures 10 and 11.

[0098] Furthermore, the connections between the introduction pin and the first vertical section C11, between the first vertical section C11 and the horizontal section C12, between the horizontal section C12 and section C31, between section C31 and section C32, between section C33 and section C34, and between section C34 and the first containment space S1 are all airtightly connected by adhesive or the like. In other words, all of the gas introduced from the introduction pin reaches the first containment space S1 via the communication section C1.

[0099] 1-7. First containment space S1 Figure 10 is a bottom view of the liquid injection head 10 when the fixed plate 15 is not shown. Figure 10 shows the gas flows FRa2, FRa3, FRa4, FRa5, FRa6, FRa7, FRa8, FRa9, FRa10, FRa11, and FRa12 in the first containment space S1. Flows FRa2 to FRa12 are a part of the flow FRa shown in Figure 6.

[0100] As can be seen from Figure 10, in a plan view, portion C34 does not overlap with the six head chips 14, but is located near the head chips 14_6. Note that portion C34 is an example of an "end portion connected to the first housing space of the communication section."

[0101] The gas discharged from section C34 fills the first containment space S1. Specifically, the gas discharged from section C34 moves in the V2 direction along the outer wall of head tip 14_6 in the W1 direction, as shown by flow FRa2, and reaches the outer wall of head tip 14_3. Flow FRa2 branches into flow FRa3 moving in the W1 direction and flow FRa4 moving in the V2 direction. A portion of the gas that reaches the outer wall of head tip 14_3 moves in the W1 direction along the outer wall of head tip 14_3 in the V1 direction, as shown by flow FRa3, and reaches the outer wall of head tip 14_5.

[0102] Flow FRa3 branches into flow FRa5, which moves in the V1 direction, and flow FRa6, which moves in the V2 direction. A portion of the gas that reaches the outer wall of head tip 14_5 moves in the W1 direction along the outer wall of head tip 14_5 in the V2 direction, as shown by flow FRa6. The same applies to the following, so to simplify the explanation, flows FRa7, FRa8, FRa9, FRa10, FRa11, and FRa12 fill the first containment space S1 with gas discharged from section C34.

[0103] Although not shown in Figure 10, gas flows other than flows FRa2 to FRa12 exist within the first containment space S1. For example, flow FRa4 moves along the outer walls of head tip 14_3 in the V2 direction and the outer walls in the W1 direction and merges with flow FRa6. Similarly, flow FRa5 moves along the outer walls of head tip 14_5 in the V1 direction and the outer walls in the W1 direction and merges with flow FRa8.

[0104] Figure 11 is a cross-sectional view showing the BB cross-section of Figure 8. The BB cross-section passes through head tips 14_6, 14_5, 14_4, and 14_1 and is parallel to the Z-axis. In Figure 11, the cross-sections of head tips 14_6, 14_5, 14_4, and 14_1 are omitted to avoid complexity in the drawing. In Figure 11, flows FRa21, FRa22, FRa23, and FRa24 are shown as part of the gas flow from the first containment space S1 to the branch path BT. Flows FRa21, FRa22, FRa23, and FRa24 are parts of the flow FRa shown in Figure 11.

[0105] The gas filling the first containment space S1 moves along the outer wall of the head tip 14 in the Z1 direction and reaches the branch path BT. In the example in Figure 11, the gas present near the outer wall of the head tip 14_5 in the direction perpendicular to the Z axis moves in the Z1 direction, as shown by flows FRa21 and FRa22, and reaches the branch path BT_5. Similarly, the gas present near the outer wall of the head tip 14_1 in the direction perpendicular to the Z axis moves in the Z1 direction, as shown by flows FRa23 and FRa24, and reaches the branch path BT_1. The branch path BT will be explained using Figure 12.

[0106] 1-8. Branch Route BT Figure 12 is a view of the CC cross-section of Figure 8 in the direction of V2. The CC cross-section is a cross-section that cuts through the drive circuit 18i that drives each of the six head chips 14. In Figure 12, the cross-sections of head chips 14_1 to 14_6 are omitted to avoid complexity in the drawing. In Figure 12, the flow FRb is shown as the gas flow in the branch path BT.

[0107] As shown in Figure 12, for a given head chip 14, the W-axis position of the drive circuit 18i and the W-axis position of the through-hole 12c or notch 12e into which the wiring board 18h ​​is inserted are different from each other. The wiring board 18h ​​bends in the W1 and W2 directions to pass through the drive circuit 18i and the through-hole 12c or notch 12e. Similarly, the branch path BT does not extend entirely along the Z-axis and also bends in the W1 and W2 directions. Consequently, the flow FRb also moves in the Z1 direction along the bent branch path BT.

[0108] As described above, the first storage space S1 is supported by a recess provided on the Z2-facing surface of the holder Du3. The six branch paths BT are holes provided in the flow path plates Du1 and Du2 and the holder Du3. Therefore, the six branch paths BT are arranged between the introduction section Pin and the first storage space S1 along the Z axis.

[0109] 1-9. Discharge route PT2 and discharge section Pout The discharge path PT2 and discharge section Pout will be explained using Figure 13. Figure 13 is a cross-sectional view showing the DD cross-section of Figure 8. The DD cross-section passes through the midpoint of the connector 17b in the X-axis direction and is parallel to the Y-axis and Z-axis. In addition, to avoid complexity in the drawing, the cross-sections of the head tips 14_2, 14_5, 14_3, and 14_6 are omitted in Figure 13. Figure 13 shows the gas flow FRc from the second containment space S2 to the discharge section Pout. Also, in Figure 13, the introduction section Pin is shown with a dashed line.

[0110] As shown in Figure 13, the second containment space S2 is formed by a recess provided on the Z2-facing surface of the filter plate Su3 and a recess provided on the Z1-facing surface of the flow path plate Du1. The gas heated by the drive circuit 18i moves in the Y1 direction at a position in the Z1 direction relative to the head substrate 12, as shown by the flow FRc. Furthermore, this gas is discharged from the liquid injection head 10 in the Z1 direction by moving in the Z1 direction at a position in the Y2 direction relative to the connector 12a and the connector substrate 17 through the hole 11e, the through hole 16h, and the discharge section Pout.

[0111] As shown in Figure 13, the inlet Pin is located at the end in the Y2 direction, and the outlet Pout is located at the end in the Y1 direction. By separating the positions of the inlet Pin and the outlet Pout, it is easier to send gas toward the head tip 14, which is farther away from the inlet Pin, in a direction perpendicular to the injection direction, compared to a configuration where the positions of the inlet Pin and the outlet Pout are close together.

[0112] As also explained in Figure 6, the gas flow from the second containment space S2 to the discharge section Pout is not limited to flow FRc. Specifically, a portion of the heated gas may move in a direction perpendicular to the Z axis at a position in the Z2 direction relative to the head substrate 12, and then move in the Z1 direction at a position in the Y1 direction relative to the connector 12a and connector substrate 17 within the hole 11e, through hole 16h, and discharge section Pout, thereby being discharged from the liquid injection head 10 in the Z1 direction.

[0113] 1-10. Positional relationship of each path within the gas path AP The positional relationships of each path within the gas path AP will be explained using Figures 14 to 16.

[0114] Figure 14 is a plan view of the liquid spray head 10 when the filter plate Su1, protective case 16, and connector board 17 are not shown. Figure 15 is a plan view of the liquid spray head 10 when the filter plate Su2 is further not shown from the state in Figure 14. Figure 16 is a plan view of the liquid spray head 10 when the filter plate Su3 is further not shown from the state in Figure 15. In Figure 16, the introduction section Pin and the horizontal section C12 are shown with dashed lines.

[0115] As shown in Figure 15, the filter unit 11 is provided with a first supply channel CC1, a second supply channel CC2, a first discharge channel CM1, a second discharge channel CM2, a first filter chamber RF1, and a second filter chamber RF2.

[0116] The first supply channel CC1 is a channel for supplying the first ink introduced into the connecting pipe 11a to the holder unit 13. Here, the first supply channel CC1 communicates with the internal space of the connecting pipe 11a via the first filter chamber RF1. The discharge port CE1, which is connected to the aforementioned connecting pipe 13a, communicates with the first supply channel CC1.

[0117] The second supply channel CC2 is a channel for supplying the second ink introduced into the connecting pipe 11b to the holder unit 13. Here, the second supply channel CC2 communicates with the internal space of the connecting pipe 11b via the second filter chamber RF2. The discharge port CE2, which is connected to the connecting pipe 13b, communicates with the second supply channel CC2.

[0118] The first discharge channel CM1 is a channel for discharging the first ink from the holder unit 13 through the connecting tube 11c. The inlet CI1, which is connected to the three connecting tubes 13c, is connected to the first discharge channel CM1.

[0119] The second discharge channel CM2 is a channel for discharging the second ink from the holder unit 13 through the connecting tube 11d. The inlet CI2, which is connected to the three connecting tubes 13d, is connected to the second discharge channel CM2.

[0120] As shown in Figure 14, the connecting pipe Su21 and the hole 11e are located apart, so the first vertical portion C11, which is a through-hole in the connecting pipe Su21, and the hole 11e do not communicate directly with each other. As shown in Figure 15, the wall Su32 and the hole 11e are located apart, so the horizontal portion C12 formed by the wall Su32 and the hole 11e do not communicate directly with each other. As shown in Figure 16, the connecting pipe 13f is formed in the bottom portion Du1a. ​​Therefore, the portion C32, which is a through-hole in the connecting pipe 13f, and the second containment space S2 formed by the bottom portion Du1a are separated from each other by the wall portion of the connecting pipe 13f. Therefore, the communication portion C1 and the discharge path PT2 do not communicate directly with each other.

[0121] Furthermore, as shown in Figure 16, a connecting pipe 13f is formed in the bottom portion Du1a. ​​That is, in a plan view, portions C31 and C32 are arranged inside the second storage space S2. Therefore, when viewed in a direction perpendicular to the Z-axis, the communication portion C1 and the discharge path PT2 overlap.

[0122] As shown in Figure 16, in a plan view, the entry pin overlaps with the head substrate 12. As shown in Figure 16, in a plan view, one end of the horizontal portion C12 furthest from the entry pin overlaps with portion C32 in a plan view. In a plan view, this portion overlapping with portion C32 is located inside the connecting tube 13f. Therefore, the portion of the horizontal portion C12 that overlaps with portion C32 does not overlap with the second housing space S2. Similarly, the portion of the horizontal portion C12 that overlaps with portion C32 does not overlap with the head substrate 12.

[0123] 1-11. Summary of the First Embodiment The liquid injection head 10 according to the first embodiment will be described below using x, y, and z, which are integers from 1 to 6 and each has a different value.

[0124] The liquid injection head 10 according to the first embodiment includes a plurality of head chips 14 that eject ink in the Z2 direction. The liquid injection head 10 includes an introduction section Pin for introducing gas supplied from a gas supply mechanism 160 into the liquid injection head 10, an discharge section Pout for discharging the gas supplied to the introduction section Pin to the outside of the liquid injection head 10, and a plurality of drive circuits 18i provided for each of the plurality of head chips 14. The plurality of head chips 14 include head chip 14_x and head chip 14_y. The plurality of drive circuits 18i include a drive circuit 18i_x for driving head chip 14_x and a drive circuit 18i_y for driving head chip 14_y. The gas path AP, through which gas flows from the inlet Pin to the outlet Pout, includes a supply path PT1 connected to the inlet Pin, an outlet path PT2 connected to the outlet Pout, a branch path BT_x connecting the supply path PT1 and the outlet path PT2, and a branch path BT_y connecting the supply path PT1 and the outlet path PT2 without passing through the branch path BT_x. The drive circuit 18i_x is located on the branch path BT_x. The drive circuit 18i_y is located on the branch path BT_y. The drive circuit 18i generates heat by driving the head chip 14. If the injection volume of head chip 14_x and the injection volume of head chip 14_y are different, it is highly likely that the amount of heat generated by the drive circuit 18i_x and the drive circuit 18i_y will also be different. The relative magnitude of the heat generated by the drive circuit 18i_x and the drive circuit 18i_y depends on the image shown in the image data Img. In an embodiment where one of the drive circuits 18i, 18i_x or 18i_y, is given priority in cooling, depending on the image shown in the image data Img, if the other drive circuit 18i generates more heat than the other drive circuit 18i, there is a risk that the other drive circuit 18i cannot be adequately cooled. When the drive circuit 18i reaches a predetermined temperature, in order to prevent the drive circuit 18i from failing due to heat, it is conceivable to stop the operation of the drive circuit 18i until the drive circuit 18i falls below the predetermined temperature. However, stopping the operation of the drive circuit 18i would extend the time required to form an image on the medium M. In the liquid injection head 10 according to the first embodiment, unheated gas is dispersed and sprayed onto the drive circuits 18i_x and 18i_y, thereby enabling uniform cooling of the drive circuits 18i_x and 18i_y. Therefore, compared to an embodiment in which one of the drive circuits 18i, either 18i_x or 18i_y, is given priority in cooling, the liquid injection head 10 according to the first embodiment can suppress situations in which the drive circuit 18i is not sufficiently cooled depending on the image shown in the image data Img.

[0125] The supply path PT1 includes a first accommodation space S1 that accommodates multiple head chips 14, and a communication section C1 that connects the introduction section Pin to the first accommodation space S1. Branch paths BT_x and BT_y are each connected to the first accommodation space S1.

[0126] The system further comprises a head board 12 connected to head chips 14_x and 14_y, and the discharge path PT2 includes a second accommodation space S2 that accommodates the head board 12, with branch paths BT_x and BT_y each connected to the second accommodation space S2.

[0127] Furthermore, the liquid injection head 10 according to the first embodiment further comprises a holder unit 13 stacked in the opposite direction to the Z2 direction on a plurality of head chips 14 and positioned between a first housing space S1 and a second housing space S2, a wiring board 18h_x connecting the head substrate 12 and the head chip 14_x and provided with a drive circuit 18i_x, and a wiring board 18h_y connecting the head substrate 12 and the head chip 14_y and provided with a drive circuit 18i_y. The holder unit 13 has through holes 13e_x that penetrate in the Z2 direction into which the wiring board 18h_x is inserted, and through holes 13e_y that penetrate in the Z2 direction into which the wiring board 18h_y is inserted. The branch path BT_x is the through hole 13e_x, and the branch path BT_y is the through hole 13e_y. In the liquid injection head 10 according to the first embodiment, the drive circuit 18i is placed in the branch path BT, which is a through hole 13e for connecting the head substrate 12 and the head chip 14. This simplifies the routing of the gas path AP compared to a configuration in which the drive circuit 18i is placed inside the case 14f.

[0128] Furthermore, the liquid injection head 10 is further equipped with a filter unit 11 that defines a surface Sa1 facing in the opposite direction to the Z1 direction of the liquid injection head 10, and the introduction pin is provided on the surface Sa1 of the filter unit 11. In the first embodiment, the liquid injection head 10 has an introduction pin on the surface Sa1 facing the Z1 direction, i.e., the upper surface, which makes it easier to attach and detach the liquid injection head 10 to the gas supply mechanism 160 compared to an embodiment where the introduction pin is provided on the side or bottom surface of the liquid injection head 10. Also, as shown in Figure 2, the multiple liquid injection heads 10 are arranged along the X axis. Therefore, the multiple liquid injection heads 10 can be arranged at a higher density compared to an embodiment where the introduction pin is provided on the side surface of the liquid injection head 10 in the X1 or X2 direction. Furthermore, the multiple liquid injection heads 10 may be arranged along the Y axis. When the multiple liquid injection heads 10 are arranged along the Y axis, the liquid injection head 10 in the first embodiment can be arranged at a higher density compared to an embodiment where the introduction pin is provided on the side surface of the liquid injection head 10 in the Y1 or Y2 direction.

[0129] On the surface Sa1 of the filter unit 11, a space inside the connecting pipes 11a and 11b, i.e., the liquid introduction section Lin, is provided for introducing ink into the liquid spray head 10. In the first embodiment, the surface Sa1 of the liquid injection head 10 has an introduction portion Pin and a liquid introduction portion Lin on a common member. Compared to an embodiment in which the introduction portion Pin and the liquid introduction portion Lin are on separate members, the number of parts constituting the liquid injection head 10 can be reduced.

[0130] Furthermore, the discharge section Pout discharges the gas to the outside of the liquid injection head 10 in the direction opposite to the Z2 direction. In the configuration in which gas is discharged in the Z1 direction, an airflow is generated between the medium M and the nozzle surface FN, which may reduce the accuracy of the liquid ejected from the nozzle N onto the medium M. On the other hand, the liquid ejection head 10 according to the first embodiment can suppress the generation of an airflow between the nozzle surface FN and the medium M compared to the configuration in which gas is discharged in the Z1 direction, thereby preventing printing defects.

[0131] Furthermore, branch paths BT_x and BT_y are positioned between the introduction section Pin and the first storage space S1 in the Z2 direction, and the communication section C1 and the discharge path PT2 are not directly connected to each other. In the configuration where the communication section C1 and the discharge path PT2 are directly connected, a portion of the gas flowing through the supply path PT1 flows into the discharge path PT2 without passing through the branch path BT. The gas that flows into the discharge path PT2 without passing through the branch path BT is discharged from the discharge section Pout without cooling the drive circuit 18i. Therefore, the liquid injection head 10 according to the first embodiment can cool the drive circuit 18i more efficiently compared to the configuration where the communication section C1 and the discharge path PT2 are directly connected.

[0132] Furthermore, when viewed in a direction perpendicular to the Z2 direction, the communication section C1 and the discharge path PT2 overlap. As described above, the liquid injection head 10 according to the first embodiment efficiently cools the drive circuit 18i because the communication section C1 and the discharge path PT2 do not communicate directly with each other, and because gas is not introduced from the side of the liquid injection head 10, multiple liquid injection heads 10 can be arranged at high density in a direction perpendicular to the Z2 direction.

[0133] Furthermore, in a plan view in the Z2 direction, the introduction pin overlaps with the head substrate 12, and the communication portion C1 includes a horizontal portion C12 that extends in a direction perpendicular to the Z2 direction. In a plan view, one end of the horizontal portion C12 that is furthest from the introduction pin does not overlap with the head substrate 12. By routing the communication portion C1 so as to bypass the head substrate 12 via the horizontal portion C12, the position where the introduction portion Pin is provided is not limited in a plan view. In other words, the liquid injection head 10 according to the first embodiment can improve the degree of freedom in the position where the introduction portion Pin is provided.

[0134] Furthermore, in a plan view in the Z2 direction, the end of the communication section C1 connected to the first housing space S1 does not overlap with the multiple head chips 14. The liquid injection head 10 according to the first embodiment makes it easier to introduce gas into the first containment space S1 compared to the method of directly blowing gas onto the head tip 14. By making it easier to introduce gas into the first containment space S1, the gas that has not been heated by the drive circuit 18i can be more uniformly filled into the first containment space S1, thereby enabling uniform cooling of the drive circuit 18i_x and the drive circuit 18i_y.

[0135] Furthermore, in a plan view in the Z2 direction, the end of the communication section C1 connected to the first housing space S1 does not overlap with the multiple head chips 14, a wiring opening is formed in the outer wall of the liquid spray head 10 into which a connector board 17 connected to the head board 12 is inserted, and the discharge section Pout is a wiring opening connected to only one end of the discharge path PT2. In the liquid spray head 10 according to the first embodiment, the wiring opening, which is the only entry point for mist and paper dust, also functions as the discharge section Pout. This simplifies the routing of the discharge path PT2, allowing for miniaturization, while also efficiently preventing the intrusion of mist and paper dust. The second containment space S2 can be made a shared space for the supply path PT1 and the discharge path PT2, thereby improving cooling efficiency. In other words, the liquid injection head 10 according to the first embodiment can achieve both mist control and improved cooling efficiency by first lowering the gas supplied from the introduction section Pin to the end in the Z2 direction where the head tip 14 is located, then moving it upward along the multiple branch paths BT and merging the branch paths BT in the second containment space S2.

[0136] In this embodiment, instead of the connector board 17 which is part of the liquid injection head 10, a wiring member such as a flexible flat cable which is an external wiring member of the liquid injection head 10 and connects the liquid injection head 10 and the control unit 120 may be provided as the "second relay board".

[0137] Furthermore, the number of entry pins is less than the number of head chips 14. The liquid injection head 10 according to the first embodiment has a simpler set of components compared to the case where an introduction pin corresponding to one-to-one is provided on the head tip 14, and the gas supply mechanism 160 can be easily attached and detached.

[0138] The number of introductory pins is one. The liquid injection head 10 according to the first embodiment has a simplified set of components compared to the case where multiple introduction pins are provided, and the gas supply mechanism 160 can be easily attached and detached.

[0139] The drive circuit 18i includes a switching element that can select whether or not to supply a drive signal Com for driving the piezoelectric element 14e for ejecting ink. The switching element generates heat by supplying a drive signal Com and by switching between supplying and not supplying the drive signal Com. In the liquid injection head 10 according to the first embodiment, compared to an embodiment in which one of the drive circuits 18i, either drive circuit 18i_x or drive circuit 18i_y, is given priority in cooling, it is possible to suppress a state in which the drive circuit 18i cannot be sufficiently cooled depending on the image shown in the image data Img.

[0140] Multiple head chips 14 include head chips 14_z, and multiple drive circuits 18i include drive circuits 18i_z for driving the head chips 14_z. The gas path AP has a branch path BT_z that connects the supply path PT1 and the discharge path PT2 so as not to pass through the branch paths BT_x and BT_y, and the drive circuits 18i_z are located on the branch path BT_z. According to the liquid injection head 10 of the first embodiment, the gas that is not heated by the drive circuit 18i is dispersed and sprayed onto the drive circuits 18i_x, 18i_y, and 18i_z, so that the drive circuits 18i_x, 18i_y, and 18i_z can be cooled uniformly.

[0141] The liquid injection device 100 according to the first embodiment includes a liquid injection head 10 and a gas supply mechanism 160 that supplies gas to the introduction pin of the liquid injection head 10. The liquid injection device 100 according to the first embodiment can uniformly cool the drive circuit 18i_x and the drive circuit 18i_y.

[0142] 2. Variations Each of the forms exemplified above can be modified in various ways. Specific examples of modifications are given below. Two or more forms arbitrarily selected from the following examples can be merged as appropriate, provided they do not contradict each other.

[0143] 2-1. First variation Figure 17 is a schematic diagram showing the path within the liquid injection head 10-A according to the first modified example. In Figure 17, the positional relationship of each element in the liquid injection head 10-A perpendicular to the Z-axis and the orientation of each element have been appropriately changed to facilitate the explanation of the path, and these differ from the original positional relationship and orientation of each element. Furthermore, Figure 17 shows the gas flows FRa-A, FRb-A, FRc-A, and FRd within the liquid injection head 10-A.

[0144] Liquid injection head 10-A differs from liquid injection head 10 in that it has a filter unit 11-A instead of filter unit 11, and a holder unit 13-A instead of holder unit 13. Due to the shapes of filter unit 11-A and holder unit 13-A, liquid injection head 10-A has a gas path AP-A instead of gas path AP. Gas path AP-A differs from gas path AP in that it has a supply path PT1-A instead of supply path PT1, and a discharge path PT2-A instead of discharge path PT2. Supply path PT1-A differs from supply path PT1 in that it has a connection part D1 instead of communication part C1, and a second storage space S2 instead of first storage space S1. Discharge route PT2-A differs from discharge route PT2 in that it has hole 11e-A instead of hole 11e, and has a first containment space S1 instead of a second containment space S2.

[0145] The connection part D1 communicates with the second accommodation space S2 from the introduction part Pin. Hole 11e-A is the same as hole 11e in that it communicates with the second accommodation space S2. The first accommodation space S1 and the second accommodation space S2 each communicate with each other via the opening 13g, which will be described later, which is different from the first accommodation space S1 and the second accommodation space S2 of the first embodiment.

[0146] In the first modified example, the gas supplied from the gas supply mechanism 160 is introduced into the second containment space S2 via the introduction pin and connection D1, as shown by flow FRa-A. Flow FRa-A is indicated by a white arrow. The gas introduced into the second containment space S2 reaches the first containment space S1 via one of the branch paths BT_1 to BT_6, as shown by flow FRb-A. Flow FRb-A is a flow from the Z1 direction to the Z2 direction. As shown in Figure 17, the holder unit 13-A is provided with an opening 13g that connects the first containment space S1 and the hole 11e-A. The drive circuit 18i is not located in the opening 13g. The heated gas is discharged in the Z1 direction via the opening 13g, the hole 11e-A, and the discharge part Pout, as shown by flow FRc-A. Flow FRc-A is indicated by a shaded arrow.

[0147] In the first modified example, the unheated gas is dispersed and blown onto each of the multiple drive circuits 18i, so that the multiple drive circuits 18i can be cooled uniformly.

[0148] In this modified example, a portion of the second containment space S2 on the inlet Pin side is part of the supply path PT1-A, and the remaining portion of the second containment space S2 (in other words, a portion on the discharge side Pout) is part of the discharge path PT2-A. That is, the supply path PT1-A and the discharge path PT2-A are directly connected. Therefore, comparing the first embodiment with the first modified example, in the first modified example, as shown in the flow FRd, a portion of the gas that is not heated by the drive circuit 18i is discharged through the hole 11e and the discharge section Pout. It is possible to provide a sealing member that divides the second containment space S2 to prevent the flow FRd from occurring, but this would increase the number of parts in the liquid injection head 10. It is also possible to prevent the flow FRd from occurring by changing the shape of the filter unit 11-A and the holder unit 13-A, but this would impose many structural constraints.

[0149] Furthermore, in the first modified example, there is a risk that gas may flow backward from the first containment space S1 to the second containment space S2 through multiple through holes 13e. Specifically, in flow FRb-A, the temperature of the gas increases as it moves downstream, but as the temperature increases, the density decreases and it becomes easier to rise, so the heated gas may move in the Z1 direction along the branch path BT. If the gas flows backward, the heated gas will be less likely to be discharged to the outside of the liquid injection head 10-A, thus reducing the cooling efficiency. Also, as mentioned above, since the supply path PT1-A and the discharge path PT2-A are directly connected, the gas flowing through the supply path PT1 may flow towards the discharge path PT2-A without going through the branch path BT, and then move towards the opening 13g instead of the discharge section Pout, and flow backward in the Z2 direction within the opening 13g. Therefore, the liquid injection head 10 according to the first embodiment can improve the cooling efficiency compared to the liquid injection head 10 according to the first modified example.

[0150] 2-2. Second variation In each of the embodiments described above, the introduction pin was provided on the upper surface of the liquid injection head 10, that is, on the surface Sa1 of the filter plate Su1, but it may also be provided on the side surface of the liquid injection head 10.

[0151] 2-3. Third Variation In the first embodiment and the second modified example based on the first embodiment, the communication section C1 and the discharge path PT2 are not in direct communication with each other, but they may be in direct communication with each other.

[0152] 2-4. Fourth Variation In the first embodiment, the second modification based on the first embodiment, and the third modification based on the first embodiment or the second modification, in a plan view, the end of the communication portion C1 connected to the first housing space S1 does not overlap with the multiple head chips 14, but it may overlap with any one of the multiple head chips 14.

[0153] 2-5. Fifth Variation In each of the embodiments described above, a connector board 17 is inserted into the discharge section Pout, but this is not limited to this.

[0154] Figure 18 is a schematic diagram showing the path within the liquid injection head 10-B according to the fifth modified example. In Figure 18, the positional relationship of each element in the liquid injection head 10-B perpendicular to the Z-axis and the orientation of each element have been appropriately changed to facilitate the explanation of the path, and these differ from the original positional relationship and orientation of each element. Furthermore, Figure 18 shows the gas flows FRa, FRb, and FRc-B within the liquid injection head 10-B.

[0155] The liquid spray head 10-B differs from the liquid spray head 10 in that it has a filter unit 11-B instead of the filter unit 11, a wiring member 19 instead of the connector board 17, and does not have a protective case 16.

[0156] The filter unit 11-B differs from the filter unit 11 in that, in a plan view, it does not overlap with the connector 12a. Because the filter unit 11-B does not overlap with the connector 12a in a plan view, a portion of the head board 12, including the connector 12a, is exposed to the outside of the liquid spray head 10. The wiring member 19 is an external wiring member of the liquid spray head 10 and connects the liquid spray head 10 to the control unit 120. One end of the wiring member 19 is connected to the connector 12a. The wiring member 19 is, for example, a flexible flat cable.

[0157] The liquid injection head 10-B has a gas path AP-B instead of the gas path AP, due to the shape of the filter unit 11-B and the holder unit 13. The gas path AP-B differs from the gas path AP in that it has an exhaust path PT2-B instead of the exhaust path PT2. The exhaust path PT2-B differs from the exhaust path PT2 in that it does not have holes 11e and through holes 16h.

[0158] The second containment space S2 according to the fifth modified example is connected to a discharge section Pout-B formed on the outer wall of the liquid injection head 10-B. The discharge section Pout-B is an opening defined by the filter unit 11-B and the holder unit 13. The discharge section Pout-B can also be described as a wiring opening into which the head substrate 12 is inserted. The discharge section Pout-B is connected to only one end of the discharge path PT-B.

[0159] As shown in Figure 18, the flow FRc-B is discharged from the second containment space S2 according to the fifth modified example, via the discharge section Pout-B, in a direction perpendicular to the Z axis. As shown in the fifth modified example, the discharge section Pout-B discharges the gas to the outside of the liquid injection head 10-B in a direction other than the Z1 direction, which is opposite to the injection direction.

[0160] 2-6. Sixth Variation The liquid spraying device 100 described above, as illustrated in Figure 1, is a so-called line-type liquid spraying device in which printing is performed simply by having multiple liquid spraying heads 10 fixed to a support 41 and transporting the medium M. However, the configuration of the liquid spraying device is not limited to that described above. For example, the present invention can also be applied to a so-called serial-type liquid spraying device in which multiple liquid spraying heads 10 are mounted on a carriage, and the multiple liquid spraying heads 10 are moved back and forth along the X-axis while transporting the medium M to perform printing.

[0161] 2-7. Other variations The liquid spraying apparatus described above can be used in various devices, including not only equipment dedicated to printing, but also facsimile machines and photocopiers. However, the applications of the liquid spraying apparatus of the present invention are not limited to printing. For example, a liquid spraying apparatus that sprays a solution of colorants can be used as a manufacturing apparatus for forming color filters for liquid crystal display devices. Furthermore, a liquid spraying apparatus that sprays a solution of conductive materials can be used as a manufacturing apparatus for forming wiring and electrodes on wiring boards.

[0162] 3. Addendum From the forms exemplified above, the following configuration can be understood, for example.

[0163] A liquid injection head according to Embodiment 1, which is a preferred embodiment, is a liquid injection head comprising a plurality of head tips for injecting liquid in the injection direction, comprising: one or more introduction parts for introducing gas supplied from a gas supply mechanism into the liquid injection head; an discharge part for discharging the gas supplied to the one or more introduction parts to the outside of the liquid injection head; and a plurality of drive circuits provided on each of the plurality of head tips, wherein the plurality of head tips include a first head tip and a second head tip, and the plurality of drive circuits drive the first head tip. The gas path, through which gas flows from one or more inlets to one or more outlets, comprises a first drive circuit for driving the second head chip and a second drive circuit for driving the second head chip, wherein the gas path comprises a first path connected to the one or more inlets, a second path connected to the outlet, a first branch path connecting the first path and the second path, and a second branch path connecting the first path and the second path so as not to pass through the first branch path, the first drive circuit being located in the first branch path and the second drive circuit being located in the second branch path. According to embodiment 1, since gas that is not heated by the drive circuit is dispersed and blown onto the first drive circuit and the second drive circuit, the first drive circuit and the second drive circuit can be cooled uniformly.

[0164] In Embodiment 2, which is a specific example of Embodiment 1, the first path includes a first housing space for housing the plurality of head chips and a communication section that connects the one or more introduction sections to the first housing space, and the first branch path and the second branch path are each connected to the first housing space.

[0165] Embodiment 3, which is a specific example of Embodiment 2, further comprises a first relay board connected to the first head chip and the second head chip, the second path includes a second housing space that houses the first relay board, and the first branch path and the second branch path are each connected to the second housing space.

[0166] In embodiment 4, which is a specific example of embodiment 3, the invention further comprises: a first member stacked on the plurality of head chips in the direction opposite to the injection direction and positioned between the first housing space and the second housing space; a first wiring board connecting the first relay board and the first head chip and providing the first drive circuit; and a second wiring board connecting the first relay board and the second head chip and providing the second drive circuit, wherein the first member has a first through-hole penetrating in the injection direction into which the first wiring board is inserted, and a second through-hole penetrating in the injection direction into which the second wiring board is inserted, and the first branch path is the first through-hole, and the second branch path is the second through-hole. According to Embodiment 4, by arranging the drive circuit in the branch path, which is a through-hole for connecting the first relay substrate and the head chip, the routing of the gas path can be simplified compared to a configuration in which the drive circuit is located inside the head chip.

[0167] In embodiment 5, which is a specific example of embodiment 1, a second member further comprises defining a first surface of the liquid injection head that faces in the opposite direction to the injection direction, and the one or more introduction portions are provided on the first surface of the second member. According to embodiment 5, since the introduction portion is provided on the first surface of the liquid injection head facing the opposite direction of the injection direction, i.e., the upper surface, it becomes easier to attach and detach the liquid injection head to the gas supply mechanism compared to embodiments in which the introduction portion is provided on the side or bottom surface of the liquid injection head.

[0168] In embodiment 6, which is a specific example of embodiment 5, the first surface of the second member is provided with a liquid introduction section for introducing liquid into the liquid injection head. According to embodiment 6, since the introduction section and the liquid introduction section are provided on a common member on the first surface, the number of parts constituting the liquid injection head can be reduced compared to an embodiment in which the introduction section and the liquid introduction section are provided on separate members.

[0169] In embodiment 7, which is a specific example of embodiment 1, the discharge unit is characterized in that it discharges the gas to the outside of the liquid injection head in a direction opposite to the injection direction. According to embodiment 7, compared to the embodiment in which gas is discharged in the spraying direction, it is possible to suppress the generation of airflow between the nozzle surface and the medium, thereby preventing printing defects.

[0170] In embodiment 8, which is a specific example of embodiment 2, the first branch path and the second branch path are arranged between the one or more introduction sections and the first containment space in the injection direction, and the communication section and the second path are not in direct communication with each other. According to embodiment 8, the drive circuit can be cooled more efficiently compared to the embodiment in which the communication section and the second path are in direct communication.

[0171] In embodiment 9, which is a specific example of embodiment 8, the communication portion and the second path overlap when viewed in a direction perpendicular to the injection direction. According to embodiment 9, as described above, by ensuring that the communication section and the second path are not directly connected to each other, the drive circuit is cooled efficiently, and since gas is not introduced from the side of the liquid injection head, multiple liquid injection heads can be arranged at high density in a direction perpendicular to the injection direction.

[0172] In embodiment 10, which is a specific example of embodiment 3, in a plan view as seen in the injection direction, the one or more introduction portions overlap the first relay substrate, the communication portion includes a portion extending in a direction perpendicular to the injection direction, and in the plan view, one end of the portion furthest from the introduction portion does not overlap the first relay substrate. By routing the communication portion so as to bypass the first relay substrate with a portion extending in a direction perpendicular to the injection direction, the position where the introduction portion is provided is not limited in a plan view. In other words, according to embodiment 10, the degree of freedom in the position where the introduction portion is provided can be improved.

[0173] In embodiment 11, which is a specific example of embodiment 2, the end portion of the communication section connected to the first housing space does not overlap with the plurality of head tips in a plan view in the direction of injection. According to embodiment 11, compared to the embodiment in which gas is directly blown onto the head tip, it is possible to facilitate the flow of gas into the first containment space.

[0174] In embodiment 12, which is a specific example of embodiment 3, in a plan view as seen in the spraying direction, the end of the communication portion connected to the first housing space does not overlap with the plurality of head chips, a wiring opening is formed in the outer wall of the liquid spraying head into which the first relay substrate or a second relay substrate connected to the first relay substrate is inserted, and the discharge portion is the wiring opening connected to only one end of the second path. According to embodiment 12, the wiring opening, which is the only entry point for mist and paper dust, also functions as an exhaust outlet, thereby simplifying the routing of the second path and making it smaller, while also efficiently preventing the entry of mist and paper dust.

[0175] In embodiment 13, which is a specific example of embodiment 1, the number of the one or more introduction sections is less than the number of the multiple head chips. According to embodiment 13, the components can be simplified compared to the case where an introduction section corresponding to one-to-one is provided on the head tip, and the gas supply mechanism can be easily attached and detached.

[0176] In embodiment 14, which is a specific example of embodiment 1, the number of the one or more introduction parts is one. According to embodiment 14, the components can be simplified compared to the case where multiple introduction sections are provided, and the gas supply mechanism can be easily attached and detached.

[0177] In embodiment 15, which is a specific example of embodiment 1, the drive circuit includes a switching element that can select whether or not to supply a drive signal for driving a drive element for spraying liquid. The switching element generates heat by supplying a drive signal and by switching between a state where a drive signal is supplied and a state where it is not supplied. According to embodiment 15, compared to an embodiment in which one of the first drive circuit or the second drive circuit is given priority in cooling, it is possible to suppress a state in which the drive circuit cannot be sufficiently cooled depending on the image shown by the image data.

[0178] In Embodiment 16, which is a specific example of Embodiment 1, the plurality of head chips include a third head chip, the plurality of drive circuits include a third drive circuit for driving the third head chip, the gas path has a third branch path that connects the first path and the second path so as not to pass through the first branch path and the second branch path, and the third drive circuit is arranged in the third branch path. According to embodiment 17, since the gas that is not heated by the drive circuit is dispersed and blown onto the first drive circuit, the second drive circuit, and the third drive circuit, the first drive circuit, the second drive circuit, and the third drive circuit can be cooled uniformly.

[0179] A liquid injection device according to embodiment 17, which is a preferred embodiment, is characterized by comprising a liquid injection head according to any one of claims 1 to 16, and a gas supply mechanism that supplies gas to the one or more inlet portions of the liquid injection head. According to embodiment 17, the first drive circuit and the second drive circuit can be cooled uniformly. [Explanation of Symbols]

[0180] 10, 10-A, 10-B…Liquid injection head, 11, 11-A, 11-B…Filter unit, 11a, 11b, 11c, 11d, 11f…Connecting tube, 11e, 11e-A…Hole, 12…Head substrate, 12a…Connector, 12b…Hole, 12c…Through hole, 12e, 12f, 12g, 12h…Notch, 13…Holder unit, 13a, 13b, 13c, 13d…Connecting tube, 13e…Through hole, 13f…Connecting tube, 13g…Opening, 14, 14_1~14_6…Head tip, 14a…Nozzle substrate, 14b…Flow path substrate, 14c…Pressure chamber substrate, 14d…Diaphragm, 14e… Piezoelectric element, 14f...case, 14g...protective plate, 14j...vibration absorber, 15...fixing plate, 15a...opening, 16...protective case, 16a,16b...component, 16c...claw, 16d...pressing member, 16e,16f...notch, 16g...flange, 16h...through hole, 17...connector board, 17a...notch, 17b,17c...connector, 18h...wiring board, 18i...drive circuit, 41...support, 41a...mounting hole, 100...liquid injection device, 110...liquid container, 120...control unit, 130...transport mechanism, 140...liquid injection module, 150...circulation mechanism, 160...gas supply mechanism, 16 2…Gas storage section, 164…Air supply tube, 166…Pump, AP, AP-A, AP-B…Gas path, BP1, BP2…Bypass path, BT_1~BT_6…Branch path, C…Pressure chamber, C1…Communication section, C11…First vertical section, C12…Horizontal section, C13…Second vertical section, CC…Supply path, CC1…First supply path, CC2…Second supply path, CE1, CE2…Discharge port, CF1…Common supply path, CF2…Common discharge path, CI1, CI2…Inlet, CM…Discharge path, CM1…First discharge path, CM2…Second discharge path, Ca, Cb…Pressure chamber, Com…Drive signal, D1…Connection Part, DM...direction, DN...arrangement direction, DS...individual discharge channel, Du1...channel plate, Du1a...bottom, Du2...channel plate, Du3...holder, Du3a...flange, FN...nozzle surface, IO1...supply port, IO2,IO3a,IO3b...discharge port, IO4a,IO4b...inlet port, Img...image data, Lin...liquid introduction section, Ln...nozzle row, M...medium, N...nozzle, Na1...first communication channel, Na2...second communication channel, Nf...nozzle channel, PJ...individual channel, PT1,PT1-A...supply path, PT2,PT2-A,PT2-B...discharge path, Pin...inlet, Pout,Pout-B…Discharge section, R1…First common liquid chamber, R2…Second common liquid chamber, RF1…First filter chamber, RF2…Second filter chamber, Ra1…Individual supply channel, Ra2…Individual discharge channel, S1…First containment space, S2…Second containment space, SI…Control signal, SP…Distribution supply channel, Sa1…Surface, Su1, Su2…Filter plate, Su21…Connecting pipe, Su22…Wall, Su2a, Su2b…Bottom, Su3…Filter plate, Su31…Connecting pipe, Su32…Wall, Su3a, Su3b…Bottom.

Claims

1. A liquid spray head comprising multiple head tips that spray liquid in the spraying direction, One or more introduction sections for introducing gas supplied from a gas supply mechanism into the liquid injection head, A discharge unit for discharging the gas supplied to the one or more introduction units to the outside of the liquid injection head, Multiple drive circuits provided on each of the aforementioned multiple head chips, Equipped with, The aforementioned plurality of head chips include a first head chip and a second head chip, The plurality of drive circuits include a first drive circuit for driving the first head chip and a second drive circuit for driving the second head chip. The gas path through which gas flows from the one or more inlet sections to the outlet section is: A first path connected to the one or more of the aforementioned entry points, A second path connected to the discharge section, A first branch path connecting the first path and the second path, The system includes a second branching path that connects the first path and the second path in a manner that avoids passing through the first branching path, The first drive circuit is arranged in the first branch path, The second drive circuit is arranged in the second branch path, The first path includes a first housing space for housing the plurality of head chips, and a communication section that connects the one or more introduction sections to the first housing space, The first branch path and the second branch path are each connected to the first accommodation space. A liquid spray head characterized by the following features.

2. The system further comprises a first relay board connected to the first head chip and the second head chip, The second path includes a second housing space for housing the first relay board, The first branch path and the second branch path are each connected to the second accommodation space. The liquid spray head according to feature 1.

3. A first member is stacked on the plurality of head chips in the direction opposite to the injection direction and is positioned between the first housing space and the second housing space, A first wiring board is provided which connects the first relay board and the first head chip and which also has the first drive circuit, A second wiring board is provided which connects the first relay board and the second head chip and which also has the second drive circuit, Furthermore, The first member includes, A first through-hole that penetrates in the injection direction and into which the first wiring board is inserted, A second through-hole is formed, which penetrates in the injection direction and into which the second wiring board is inserted. The first branching path is the first through hole, The aforementioned second branch path is the aforementioned second through hole. The liquid spray head according to feature 2.

4. The device further comprises a second member that defines a first surface facing in the opposite direction to the spray direction of the liquid spray head, The one or more introduction portions are provided on the first surface of the second member, The liquid spray head according to feature 1.

5. A liquid spray head comprising a plurality of head tips for spraying liquid in the spray direction, One or more introduction sections for introducing gas supplied from a gas supply mechanism into the liquid injection head, A discharge unit for discharging the gas supplied to the one or more introduction units to the outside of the liquid injection head, Multiple drive circuits provided on each of the aforementioned multiple head chips, A second member defining a first surface of the liquid injection head that faces in the opposite direction to the injection direction, Equipped with, The aforementioned plurality of head chips include a first head chip and a second head chip, The plurality of drive circuits include a first drive circuit for driving the first head chip and a second drive circuit for driving the second head chip. The gas path through which gas flows from the one or more inlet sections to the outlet section is: A first path connected to the one or more of the aforementioned entry points, A second path connected to the discharge section, A first branch path connecting the first path and the second path, The system includes a second branching path that connects the first path and the second path in a manner that avoids passing through the first branching path, The first drive circuit is arranged in the first branch path, The second drive circuit is arranged in the second branch path, The one or more introduction portions are provided on the first surface of the second member, A liquid spray head characterized by the following features.

6. The first surface of the second member is provided with a liquid introduction section for introducing liquid into the liquid injection head. The liquid spray head according to claim 4 or 5.

7. The discharge unit discharges the gas to the outside of the liquid injection head in the direction opposite to the injection direction. The liquid spray head according to feature 1.

8. A liquid spray head comprising a plurality of head tips for spraying liquid in the spray direction, One or more introduction sections for introducing gas supplied from a gas supply mechanism into the liquid injection head, A discharge unit for discharging the gas supplied to the one or more introduction units to the outside of the liquid injection head, Multiple drive circuits provided on each of the aforementioned multiple head chips, Equipped with, The aforementioned plurality of head chips include a first head chip and a second head chip, The plurality of drive circuits include a first drive circuit for driving the first head chip and a second drive circuit for driving the second head chip. The gas path through which gas flows from the one or more inlet sections to the outlet section is: A first path connected to the one or more of the aforementioned entry points, A second path connected to the discharge section, A first branch path connecting the first path and the second path, The system includes a second branching path that connects the first path and the second path in a manner that avoids passing through the first branching path, The first drive circuit is arranged in the first branch path, The second drive circuit is arranged in the second branch path, The discharge unit discharges the gas to the outside of the liquid injection head in the direction opposite to the injection direction. A liquid spray head characterized by the following features.

9. The first branch path and the second branch path are arranged between the one or more introduction sections and the first containment space in the injection direction. The aforementioned communication section and the second path are not directly connected to each other. The liquid spray head according to feature 1.

10. When viewed in a direction perpendicular to the injection direction, the communication portion and the second path overlap. The liquid spray head according to feature 9.

11. In a plan view as seen in the injection direction, the one or more introduction sections overlap the first relay substrate. The communicating portion includes a portion that extends in a direction perpendicular to the injection direction, In the plan view, one end of the portion furthest from the introduction portion does not overlap with the first relay board. The liquid spray head according to feature 2.

12. In a plan view as seen in the injection direction, the end of the communication portion connected to the first housing space does not overlap with the plurality of head tips. The liquid spray head according to feature 1.

13. In a plan view as seen in the injection direction, the end of the communication portion connected to the first housing space does not overlap with the plurality of head tips. The outer wall of the liquid injection head has a wiring opening into which the first relay board, or a second relay board connected to the first relay board, is inserted. The discharge section is the wiring opening connected to only one end of the second path. The liquid spray head according to feature 2.

14. The number of the one or more introduction sections is less than the number of the multiple head chips. A liquid spray head according to any one of claims 1, 5, or 8.

15. The number of the aforementioned one or more introduction sections is one. A liquid spray head according to any one of claims 1, 5, or 8.

16. The drive circuit includes a switching element that can select whether or not to supply a drive signal for driving a drive element for spraying liquid. A liquid spray head according to any one of claims 1, 5, or 8.

17. The aforementioned plurality of head chips include a third head chip, The plurality of drive circuits include a third drive circuit for driving the third head chip. The gas path has a third branch path that connects the first path and the second path so as not to pass through the first branch path and the second branch path. The third drive circuit is arranged in the third branch path, A liquid spray head according to any one of claims 1, 5, or 8.

18. A liquid spray head according to any one of claims 1, 5, or 8, The gas supply mechanism supplies gas to the one or more inlet ports of the liquid injection head, A liquid injection device characterized by being equipped with the following features.

Images