Liquid jet head and liquid jet recording apparatus

Abstract

To provide a liquid jet head and a liquid jet recording apparatus which can obtain the stable discharge performance.SOLUTION: An ink jet head 5 comprises: a head chip in which a plurality of discharge channels sequentially arrayed in a -X direction from a + X direction of an X direction are provided and which jets ink in the discharge channels; a channel member 44 which has a guide channel 104 that guides ink in the - X direction from the + X direction of the X direction and in which the guide channel 104 is connected to each discharge channel; and a substrate unit on which a plurality of drive ICs 84 arrayed along the X direction are mounted, and which is thermally connected to the channel member 44. The channel member 44 includes a cooling channel 102 which guides ink in the + X direction from the - X direction of the X direction to cool the plurality of drive ICs 84.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a liquid jet head and a liquid jet recording apparatus. [Background technology]

[0002] Patent Document 1 discloses a liquid jet head that can efficiently cool a driving IC in a circuit section and simplify the device configuration. The liquid jet head disclosed in Patent Document 1 includes a head section, a circuit section, and a cooling section. The head section includes a supply flow path through which liquid supplied from the outside flows, a pressure chamber communicating with the supply flow path, a driving element that drives the pressure chamber, and a nozzle communicating with the pressure chamber, and ejects droplets from the nozzle. The circuit section supplies a driving waveform to the driving element. The cooling section includes a cooling flow path through which the liquid flows, and is connected and fixed to the circuit section. Furthermore, in Patent Document 1, liquid flows in parallel through the supply flow path and the cooling flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-171806 Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid jet head disclosed in Patent Document 1, a driving IC is cooled by liquid flowing through a cooling channel arranged in parallel to a supply channel. Therefore, the temperature of the liquid flowing through the cooling channel increases as it moves downstream. Furthermore, the temperature of the liquid flowing through the supply channel increases as it moves downstream due to the influence of heat from a driving element that drives a pressure chamber connected to the supply channel. In Patent Document 1, the flow direction of the liquid in the cooling channel is the same as the flow direction of the liquid in the supply channel. Furthermore, the upstream end of the cooling channel is connected to the upstream end of the supply channel, and the downstream end of the cooling channel is connected to the downstream end of the supply channel. In other words, the liquid heated in the cooling channel and the liquid heated in the supply channel merge on one side of the extension direction of the cooling channel and the supply channel. Therefore, in the liquid jet head disclosed in Patent Document 1, heat is concentrated on one side of the extension direction of the cooling channel and the supply channel, resulting in a large temperature difference between one side and the other side of the extension direction throughout the liquid jet head.

[0005] In the liquid jet head disclosed in Patent Document 1, the heat distribution throughout the liquid jet head is largely uneven. Therefore, if multiple pressure chambers are arranged linearly along the extension direction of the cooling flow path and the supply flow path, the temperature difference depending on the position of the pressure chamber becomes large. As a result, the viscosity of the liquid varies depending on the position of the pressure chamber, which may lead to ejection defects such as differences in the amount of liquid ejected depending on the position of the pressure chamber.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a liquid jet head and a liquid jet recording apparatus that can obtain stable ejection performance. [Means for solving the problem]

[0007] In order to solve the above problems, the present disclosure employs the following aspects. (1) A liquid ejection head according to one aspect of the present disclosure includes a plurality of pressure chambers arranged sequentially from one side to the other side in a first direction, an ejection unit that ejects liquid inside the pressure chambers, a flow path member that is provided with guide flow paths that guide the liquid from one side to the other side in the first direction and the guide flow paths are connected to each of the pressure chambers, and a circuit board that is mounted with a plurality of drive control units arranged along the first direction and is thermally connected to the flow path member, and the flow path member is provided with cooling flow paths that guide the liquid from the other side to the one side in the first direction to cool the plurality of drive control units.

[0008] The heat sources in a liquid jet head are mainly two: an ejection unit provided with a pressure chamber that ejects liquid, and a plurality of drive control units. According to this aspect, the flow path member is provided with a guide flow path connected to the pressure chamber of the ejection unit, which is one of these heat sources. The flow path member is also provided with a cooling flow path that cools the plurality of drive control units, which are one of these heat sources. In the guide flow path and the cooling flow path, the flow direction of the liquid in the guide flow path is opposite to the flow direction of the liquid in the cooling flow path that cools the drive control unit. Therefore, in the guide flow path, the other side in the first direction is relatively hotter than the one side. On the other hand, in the cooling flow path, the one side in the first direction is relatively hotter than the other side. As a result, the temperature distribution across the entire liquid jet head is more uniform than when the liquid flow direction in the guide flow channel and the liquid flow direction in the cooling flow channel are the same. By making the overall heat distribution across the liquid jet head uniform, the temperature of the liquid supplied to each pressure chamber is made uniform, and the viscosity of the liquid in each pressure chamber is also made uniform. Therefore, stable ejection performance can be obtained. Furthermore, by making the overall heat distribution across the liquid jet head uniform, the maximum temperature reached by the drive control unit can be reduced, allowing the drive control unit to be driven stably.

[0009] (2) In the liquid jet head of the above aspect (1), the flow path member is provided with an inflow flow path that guides the liquid flowing in from the outside and an exhaust flow path that guides the liquid to be discharged to the outside, and the guide flow path and the cooling flow path are arranged in parallel between the inflow flow path and the exhaust flow path.

[0010] According to this aspect, the distance from the inlet flow channel to the pressure chamber is shorter than when a cooling flow channel is disposed between the inlet flow channel and the guide flow channel, which reduces the pressure loss to the pressure chamber, prevents a shortage of liquid supply to the pressure chamber, and enables stable ejection of liquid from the pressure chamber.

[0011] (3) In the liquid ejection head of the aspect (2) above, the flow path member is provided with a first connection flow path arranged between the inlet flow path and the upstream end of the cooling flow path, and a second connection flow path arranged between the downstream end of the cooling flow path and the outlet flow path, and the first connection flow path and the second connection flow path guide the liquid from one side to the other side of the first direction.

[0012] According to this aspect, a serpentine flow path is formed that is made up of the first connection flow path, the cooling flow path, and the second connection flow path, which makes it possible to further uniformize the overall heat distribution of the liquid jet head.

[0013] (4) In the liquid jet head of the above aspect (1), the flow path member is provided with an inflow flow path that guides the liquid flowing in from the outside and an exhaust flow path that guides the liquid to be discharged to the outside, and the inflow flow path, the guide flow path, the cooling flow path, and the exhaust flow path are arranged in series.

[0014] According to this aspect, the liquid supplied to the pressure chamber flows through the cooling channel. This makes it possible to prevent pressure from dispersing throughout the entire channel through which the liquid flows, compared to when the guide channel and the cooling channel are arranged in parallel between the inlet channel and the outlet channel. Therefore, if the pressure at the inlet of the inlet channel and the outlet of the outlet channel is set to the same conditions as when the guide channel and the cooling channel are arranged in parallel between the inlet channel and the outlet channel, the flow rate of the liquid increases. This makes it possible to improve the cooling efficiency in the cooling channel.

[0015] (5) In the liquid jet head according to the aspect (4) above, the inflow channel, the cooling channel, the guide channel, and the discharge channel are arranged in this order.

[0016] Generally, the drive control unit becomes hotter than the ejection unit. According to this aspect, the liquid flows through the cooling flow path before the guide flow path. Therefore, the liquid at a lower temperature can be used to cool the drive control unit, compared to when the liquid that has risen in temperature after flowing through the guide flow path is then passed through the cooling flow path. This improves the cooling efficiency of the drive control unit.

[0017] (6) In the liquid jet head according to the aspect (4) above, the inflow channel, the guide channel, the cooling channel, and the discharge channel are arranged in this order.

[0018] According to this aspect, the distance from the inlet flow channel to the pressure chamber is shorter than when a cooling flow channel is disposed between the inlet flow channel and the guide flow channel, which reduces the pressure loss to the pressure chamber, prevents a shortage of liquid supply to the pressure chamber, and enables stable ejection of liquid from the pressure chamber.

[0019] (7) In the liquid ejection head of the above aspect (5) or (6), the flow path member is provided with a third connection flow path connecting the guide flow path and the cooling flow path, and a fourth connection flow path connected to an end of the cooling flow path opposite to the end connected to the third connection flow path, and at least one of the third connection flow path and the fourth connection flow path guides the liquid from one side to the other side in the first direction at least in part.

[0020] According to this aspect, a serpentine flow path is formed that is made up of the third connection flow path, the cooling flow path, and the fourth connection flow path, which makes it possible to further uniformize the overall heat distribution of the liquid jet head.

[0021] (8) A liquid jet head according to any one of the above aspects (2) to (7) is provided with an inlet port connected to the upstream end of the inlet flow path and an outlet port connected to the downstream end of the outlet flow path, and the inlet port and the outlet port are arranged adjacent to each other on one side or the other side of the center of the flow path member in the first direction.

[0022] According to this aspect, the liquid supply pipe connected to the inlet port and the liquid discharge pipe connected to the discharge port can be arranged close together, which makes the inlet port and the discharge port less likely to interfere with other components than when the inlet port and the discharge port are arranged far apart. Furthermore, the liquid flows from one side to the other side in the cooling flow path, and from one side to the other in the guide flow path. Therefore, when the guide flow path and the cooling flow path are arranged in series, it is possible to minimize the length of the flow path through which the liquid flows.

[0023] (9) In the liquid jet head according to the aspect (8) above, the inflow channel has a separation portion that separates from the discharge channel as it moves downstream.

[0024] According to this aspect, it is possible to prevent the liquid flowing through the inlet flow path from being heated by the high-temperature liquid flowing through the outlet flow path, and therefore it is possible to supply low-temperature liquid to the cooling flow path and improve the cooling efficiency of the drive control unit compared to when the separation portion is not provided.

[0025] (10) In the ejection head according to any one of the aspects (2) to (9) above, the flow path member is provided with a second cooling flow path that allows the liquid to flow from one side to the other side of the first direction, and the second cooling flow path cools some of the drive control units that are located on the other side among the multiple drive control units.

[0026] According to this aspect, the drive control unit, which is located in a position where it is likely to be heated by the high-temperature liquid flowing through the discharge flow path, can be locally cooled, thereby further reducing the maximum temperature that the drive control unit can reach.

[0027] (11) A liquid jet recording apparatus according to one aspect of the present disclosure includes the liquid jet head according to any one of the above aspects (1) to (10).

[0028] According to this aspect, since the liquid jet head of the above aspect is provided, a liquid jet recording apparatus having stable ejection performance can be provided. [Effects of the Invention]

[0029] According to the present disclosure, stable ejection performance can be obtained. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic configuration diagram of a printer according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating the configuration of an inkjet head and an ink circulation mechanism according to the first embodiment. [Figure 3] 1 is a perspective view of an inkjet head according to a first embodiment. [Figure 4] FIG. 2 is a partially exploded perspective view of the inkjet head according to the first embodiment. [Figure 5] FIG. 2 is an enlarged exploded perspective view including a head chip according to the first embodiment. [Figure 6] FIG. 2 is a diagram including a cross section of an ejection channel in the head chip according to the first embodiment. [Figure 7] FIG. 2 is a diagram including a cross section of a non-ejection channel in the head chip according to the first embodiment. [Figure 8] FIG. 2 is an exploded perspective view including a first flow path plate and a flow path cover according to the first embodiment. [Figure 9] 1 is a schematic diagram of an inkjet head including an ink flow path according to a first embodiment. [Figure 10] FIG. 4 is a schematic diagram of an inkjet head including an ink flow path according to a modified example of the first embodiment. [Figure 11] FIG. 10 is a schematic diagram of an inkjet head including an ink flow path according to a second embodiment. [Figure 12] FIG. 10 is a schematic diagram of an inkjet head including an ink flow path according to a modified example of the second embodiment. [Figure 13] FIG. 10 is a schematic diagram of an inkjet head including an ink flow path according to a third embodiment. [Figure 14] FIG. 11 is a schematic diagram of an inkjet head including an ink flow path according to a modified example of the third embodiment. [Figure 15] FIG. 10 is a schematic diagram of an inkjet head including an ink flow path according to a fourth embodiment. [Figure 16] FIG. 11 is a schematic diagram of an inkjet head including an ink flow path according to a modified example of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the embodiments and modified examples described below, corresponding components may be designated by the same reference numerals, and their description may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly refer to such arrangements, but also refer to a state in which there is a relative displacement with a tolerance or an angle or distance that provides the same function. In the following embodiment, an inkjet printer (hereinafter simply referred to as a printer) that records on a recording medium using ink (liquid) will be described as an example. In the drawings used in the following description, the scale of each component has been appropriately changed to make each component recognizable.

[0032] (First embodiment) [Printer 1] FIG. 1 is a schematic diagram of the printer 1. The printer (liquid jet recording apparatus) 1 shown in FIG. 1 includes a pair of transport mechanisms 2 and 3, an ink tank 4, an inkjet head (liquid jet head) 5, an ink circulation mechanism 6, and a scanning mechanism .

[0033] In the following explanation, an X, Y, Z Cartesian coordinate system will be used as necessary. In this case, the X direction corresponds to the transport direction (sub-scanning direction) of the recording medium P (e.g., paper, etc.). The Y direction corresponds to the scanning direction (main scanning direction) of the scanning mechanism 7. The Z direction indicates the height direction (gravity direction) perpendicular to the X and Y directions. In the following explanation, of the X, Y, and Z directions, the arrow side in the figure is the plus (+) side, and the opposite side to the arrow is the minus (-) side. In this specification, the +Z side corresponds to the upward direction in the direction of gravity, and the -Z side corresponds to the downward direction in the direction of gravity.

[0034] The transport mechanisms 2 and 3 transport the recording medium P to the +X side. The transport mechanisms 2 and 3 each include a pair of rollers 11 and 12 extending in the Y direction, for example. The ink tanks 4 each contain four different colors of ink, for example, yellow, magenta, cyan, and black. Each inkjet head 5 is configured to be able to eject one of the four colors of ink, yellow, magenta, cyan, or black, depending on the ink tank 4 connected to it.

[0035] FIG. 2 is a schematic diagram of the inkjet head 5 and the ink circulation mechanism 6. As shown in FIG. 2, the ink circulation mechanism 6 circulates ink between the ink tank 4 and the inkjet head 5. Specifically, the ink circulation mechanism 6 includes a circulation flow path 23 having an ink supply pipe 21 and an ink discharge pipe 22, a pressure pump 24 connected to the ink supply pipe 21, and a suction pump 25 connected to the ink discharge pipe 22.

[0036] The pressure pump 24 pressurizes the ink supply pipe 21 and sends ink to the inkjet head 5 through the ink supply pipe 21. As a result, the ink supply pipe 21 side relative to the inkjet head 5 is under positive pressure. The suction pump 25 reduces the pressure inside the ink discharge pipe 22 and sucks ink from the inkjet head 5 through the ink discharge pipe 22. This creates a negative pressure on the ink discharge pipe 22 side relative to the inkjet head 5. By driving the pressure pump 24 and the suction pump 25, the ink can be circulated between the inkjet head 5 and the ink tank 4 through the circulation flow path 23.

[0037] 1, the scanning mechanism 7 moves the inkjet head 5 back and forth in the Y direction. The scanning mechanism 7 includes a pair of guide rails 28, 29 extending in the Y direction, a carriage 30 movably supported on the pair of guide rails 28, 29, and a drive mechanism 31 that moves the carriage 30 in the Y direction. The transport mechanisms 2, 3 and the scanning mechanism 7 move the inkjet head 5 and the recording medium P relative to each other.

[0038] The drive mechanism 31 is disposed between the guide rails 28 and 29 in the X direction. The drive mechanism 31 includes a pair of pulleys 32 and 33 spaced apart in the Y direction, an endless belt 34 wound between the pair of pulleys 32 and 33, and a drive motor 35 that drives one of the pulleys 32 to rotate.

[0039] The carriage 30 is connected to an endless belt 34. The carriage 30 is equipped with a plurality of inkjet heads 5. In this embodiment, an inkjet head 5 that ejects yellow ink, an inkjet head 5 that ejects magenta ink, an inkjet head 5 that ejects cyan ink, and an inkjet head 5 that ejects black ink are provided. These inkjet heads 5 are arranged side by side in the Y direction.

[0040] [Inkjet head 5] Fig. 3 is a perspective view of the inkjet head 5. Fig. 4 is a perspective view of the inkjet head 5, with a portion thereof exploded. 3 and 4, the inkjet head 5 includes a base member 40, a jet module 41, and a nozzle guard 42. The jet module 41 and the nozzle guard 42 are fixed to the base member 40. The base member 40 is fixed to the carriage 30.

[0041] [Base member 40] The base member 40 is formed in a plate shape with its thickness direction in the Z direction and its length direction in the X direction. In this embodiment, the base member 40 is integrally formed from a metal material.

[0042] A module accommodating portion 40a is formed in the base member 40. The module accommodating portion 40a penetrates the base member 40 in the Z direction. A jet module 41 can be inserted into the module accommodating portion 40a. That is, by inserting the -Z direction end of the jet module 41 into the module accommodating portion 40a, the jet module 41 is held by the base member 40 in a state where it stands upright in the +Z direction from the base member 40. The base member 40 is formed with mounting holes and the like for mounting the base member 40 to the carriage 30 (see FIG. 1).

[0043] [Jet Module 41] 3 and 4, the jet module 41 is formed in a plate shape with its thickness direction in the Y direction. The jet module 41 is configured to be able to eject ink supplied from an ink tank 4 (see FIG. 1) toward a recording medium P. The jet module 41 includes a head chip 43 (ejection unit), a flow path member 44, a feedback plate 45 (see FIG. 5), a nozzle plate 46 (see FIG. 5), and a substrate unit 47 (circuit board).

[0044] [Head chip 43] 5 is an enlarged exploded perspective view including head chip 43. Two head chips 43 are provided so as to sandwich a second flow path plate 78 (described later) of flow path member 44 between them in the Y direction. That is, in this embodiment, two head chips 43 are provided as a pair. These head chips 43 have a symmetrical structure with the second flow path plate 78 sandwiched between them. For this reason, the structure of one head chip 43 will be described, and a detailed description of the structure of the other head chip 43 will be omitted.

[0045] The head chip 43 includes an actuator plate 48 and a cover plate 49. A plurality of channels 50, 51 are formed in the actuator plate 48. One of the channels 50 is a channel that is filled with ink, and will be referred to below as an ejection channel 50 (pressure chamber). The other channel 51 is a channel that is not filled with ink, and will be referred to below as a non-ejection channel 51.

[0046] Fig. 6 is a diagram including a cross section of an ejection channel 50 in one head chip 43. Fig. 7 is a diagram including a cross section of a non-ejection channel 51 in one head chip 43. 6, a common electrode 56 is formed on the inner surface of the ejection channel 50. The common electrode 56 is formed on the entire inner surface of the ejection channel 50. As shown in FIG. 7, an individual electrode 58 is formed on the inner surface of the non-ejection channel 51. The individual electrodes 58 are formed on the inner surfaces of the non-ejection channels 51 that face each other in the X direction.

[0047] The cover plate 49 is formed with a liquid supply path 62 that penetrates the cover plate 49 in the Y direction and communicates with the ejection channels 50. The liquid supply path 62 includes a common ink chamber 63 and a plurality of slits 64 that communicate with the common ink chamber 63 and are arranged at intervals in the X direction. The common ink chamber 63 communicates with each of the ejection channels 50 through the slits 64. On the other hand, the common ink chamber 63 does not communicate with the non-ejection channels 51. Ink flows into the common ink chamber 63 through the flow path member 44. The slit 64 is disposed at a position facing the common ink chamber 63 in the Y direction. The slit 64 communicates with the common ink chamber 63 and the ejection channel 50.

[0048] The common electrode 56 formed on the inner surface of the plurality of ejection channels 50 is electrically connected to a drive substrate 82 (described later) of the substrate unit 47. The individual electrodes 58 formed on the inner surface of the plurality of non-ejection channels 51 are electrically connected to a wiring substrate 83 (described later) of the substrate unit 47.

[0049] 5, the head chips 43 are arranged at intervals in the Y direction. The ejection channels 50 and non-ejection channels 51 of one head chip 43 are arranged at a half-pitch offset in the X direction relative to the arrangement pitch of the ejection channels 50 and non-ejection channels 51 of the other head chip 43.

[0050] As described above, in this embodiment, the head chip 43 is provided with a plurality of ejection channels 50 (pressure chambers) arranged sequentially from the +X direction (one side) to the -X direction (other side) of the X direction (first direction), and ejects ink inside the ejection channels 50.

[0051] [Flow path member 44] As shown in FIG. 4, the flow path member 44 includes a first flow path plate 72, a flow path cover 73, an inlet port 74, an outlet port 75, an inlet manifold 76, an outlet manifold 77, a second flow path plate 78, and a heat transfer plate 79.

[0052] Fig. 8 is an exploded perspective view including the first flow path plate 72 and the flow path cover 73. As shown in Fig. 8, the first flow path plate 72 is formed in a rectangular plate shape with its front and back surfaces facing in the Y direction. The first flow path plate 72 is integrally formed from the same member. When viewed from the Y direction, the outer shape of the first flow path plate 72 is formed in a rectangular shape.

[0053] As shown in Fig. 8, two insertion portions 72a are provided at the end of the first flow path plate 72 in the -Z direction. These insertion portions 72a are spaced apart in the X direction and arranged along the X direction. Each insertion portion 72a is formed as a hollow body having an internal space that is open toward the -Z direction. One insertion portion 72a is disposed at the end of the first flow path plate 72 in the +X direction, and as shown in Figs. 3 and 4, an inlet manifold 76 is inserted into it from the -Z direction. The other insertion portion 72a is disposed at the end of the first flow path plate 72 in the -X direction, and as shown in Figs. 3 and 4, an outlet manifold 77 is inserted into it from the -Z direction.

[0054] 8, a first internal flow path 72b, a second internal flow path 72c, a third internal flow path 72d, and a fourth internal flow path 72e are provided inside the first flow path plate 72. The first internal flow path 72b is provided to extend in the Z direction and is connected to the inlet port 74 from the -Z direction. The second internal flow path 72c is provided to extend in the Z direction and is connected to the internal space of the insertion portion 72a into which the inlet manifold 76 is inserted from the +Z direction.

[0055] The third internal flow path 72d is provided to extend in the Z direction and is connected from the +Z direction to the internal space of the insertion portion 72a into which the outlet manifold 77 is inserted. The fourth internal flow path 72e is provided to extend in the Z direction and is connected to the internal space of the discharge port 75 from the -Z direction.

[0056] 8, a first groove portion 72f and a second groove portion 72g are provided in the first flow path plate 72. The first groove portion 72f and the second groove portion 72g are both exposed on the surface of the first flow path plate 72 in the +Y direction. In other words, the first groove portion 72f and the second groove portion 72g are open in the -Y direction.

[0057] The first groove portion 72f connects the first internal flow path 72b and the second internal flow path 72c and guides ink between the first internal flow path 72b and the second internal flow path 72c. As shown in FIG. 8, the first groove portion 72f has a first inlet end 72h connected to the first internal flow path 72b from the -Z direction. The first groove portion 72f also has a first vertical portion 72i extending from the first inlet end 72h in the -Z direction. The first groove portion 72f also has a first inclined portion 72j that is displaced in the -X direction as it moves from the -Z direction end of the first vertical portion 72i toward the -Z direction. The first groove portion 72f also has a horizontal portion 72k that extends in the +X direction from the -Z direction end of the first inclined portion 72j. The first groove portion 72f also has a second vertical portion 72m that extends in the -Z direction from the +X direction end of the horizontal portion 72k. The first groove portion 72f also has a first outlet end 72n that is connected to the -Z direction end of the second vertical portion 72m from the -Z direction and is connected to the second internal flow path 72c from the +Z direction.

[0058] The second groove portion 72g connects the third internal flow path 72d and the fourth internal flow path 72e and guides ink between the third internal flow path 72d and the fourth internal flow path 72e. As shown in FIG. 8, the second groove portion 72g has a second inlet end portion 72p connected to the third internal flow path 72d from the +Z direction. The second groove portion 72g also has a third vertical portion 72q extending in the +Z direction from the second inlet end portion 72p. The second groove portion 72g also has a second inclined portion 72r that is displaced in the +X direction as it moves from the +Z direction end of the third vertical portion 72q toward the +Z direction. The second groove portion 72g also has a fourth vertical portion 72s that extends in the +Z direction from the +Z direction end of the second inclined portion 72r. The second groove portion 72g has a second outlet end 72t that is connected to the +Z direction end of the fourth vertical portion 72s from the +Z direction and that is connected to the fourth internal flow path 72e from the -Z direction.

[0059] 8, the first internal flow path 72b and the fourth internal flow path 72e are disposed at the same position in the Z direction. Moreover, both the first internal flow path 72b and the fourth internal flow path 72e are disposed in the −X direction relative to the center position of the first flow path plate 72 in the X direction.

[0060] The second internal flow path 72c and the third internal flow path 72d are disposed at the same position in the Z direction. The second internal flow path 72c is disposed in the +X direction from the center position in the X direction of the first flow path plate 72. The third internal flow path 72d is disposed in the -X direction from the center position in the X direction of the first flow path plate 72.

[0061] The first inlet end 72h and the second outlet end 72t are disposed at the same position in the Z direction. The first inlet end 72h and the second outlet end 72t are both disposed in the -X direction relative to the center position of the first flow path plate 72 in the X direction.

[0062] The first vertical portion 72i and the fourth vertical portion 72s are disposed at approximately the same position in the Z direction. The first vertical portion 72i and the fourth vertical portion 72s are both disposed in the -X direction relative to the center position of the first flow path plate 72 in the X direction.

[0063] The first inclined portion 72j and the second inclined portion 72r are disposed at approximately the same position in the Z direction. The first inclined portion 72j and the second inclined portion 72r are both disposed in the -X direction relative to the center position of the first flow path plate 72 in the X direction.

[0064] Furthermore, the −X direction end of the horizontal portion 72k is disposed in the −X direction from the center position in the X direction of the first flow path plate 72. The +X direction end of the horizontal portion 72k is disposed in the +X direction from the center position in the X direction of the first flow path plate 72.

[0065] The second vertical portion 72m and the first outlet end portion 72n are disposed in the +X direction from the center position in the X direction of the first flow path plate 72. The second inlet end portion 72p and the third vertical portion 72q are disposed in the -X direction from the center position in the X direction of the first flow path plate 72.

[0066] The flow path cover 73 is a plate member joined to the surface of the first flow path plate 72 in the -Y direction. When viewed from the Y direction, the width of the flow path cover 73 in the X direction is the same as the width of the first flow path plate 72 in the X direction. In addition, the end of the flow path cover 73 in the +Z direction is disposed at the same position in the Z direction as the end of the first flow path plate 72 in the +Z direction. The height of the flow path cover 73 in the Z direction is set to a dimension that enables the flow path cover 73 to cover the entire first groove portion 72f and the second groove portion 72g.

[0067] The inflow port 74 is provided to protrude in the +Z direction from the surface (top surface) facing the +Z direction of the first flow path plate 72. The inflow port 74 is connected to the ink supply tube 21 (see FIG. 1). The inflow port 74 is also connected to the first internal flow path 72b of the first flow path plate 72 from the +Z direction. The inflow port 74 guides ink supplied from the ink supply tube 21 to the first internal flow path 72b.

[0068] The discharge port 75 is provided to protrude in the +Z direction from the surface (top surface) facing the +Z direction of the first flow path plate 72. The discharge port 75 is connected to the ink discharge tube 22 (see FIG. 1). The discharge port 75 is also connected to the fourth internal flow path 72e of the first flow path plate 72 from the +Z direction. The discharge port 75 guides ink discharged from the fourth internal flow path 72e to the ink discharge tube 22.

[0069] In this embodiment, the first internal flow path 72b and the fourth internal flow path 72e are both disposed in the −X direction from the center position in the X direction of the first flow path plate 72. Therefore, the inlet port 74 connected to the first internal flow path 72b and the outlet port 75 connected to the fourth internal flow path 72e are both disposed in the −X direction from the center position in the X direction of the first flow path plate 72.

[0070] As described above, this embodiment includes an inlet port 74 connected to the upstream end (end in the +Z direction) of the first internal flow path 72b, and an outlet port 75 connected to the downstream end (end in the +Z direction) of the fourth internal flow path 72e. The inlet port 74 and the outlet port 75 are disposed adjacent to each other in the -X direction (one side) of the center of the flow path member 44 in the X direction (first direction).

[0071] Furthermore, by changing the positions of the first internal flow path 72b and the fourth internal flow path 72e, or the positions and shapes of the first groove portion 72f and the second groove portion 72g, it is also possible to position the inlet port 74 and the outlet port 75 adjacent to each other in the +X direction (the other side) of the center of the flow path member 44 in the X direction (first direction).

[0072] The inlet manifold 76 (see FIG. 5) is joined together to the +X direction ends of the two head chips 43 and the second flow path plate 78, and is inserted into the +X direction insertion portion 72a of the first flow path plate 72. The inlet manifold 76 has an inlet protrusion 76a that is inserted into the insertion portion 72a from the -Z direction. The inlet manifold 76 also has an inlet base 76b that is connected to the inlet protrusion 76a from the -Z direction and is joined to the +X direction ends of the two head chips 43 and the second flow path plate 78. The inlet manifold 76 also has an internal flow path 76c. The internal flow path 76c has an open end at the +Z direction end of the inlet protrusion 76a and at the -X direction surface of the inlet base 76b.

[0073] The inlet manifold 76 (see FIG. 5) is joined together to the +X direction ends of the two head chips 43 and the second flow path plate 78, and is inserted into the +X direction insertion portion 72a of the first flow path plate 72. The inlet manifold 76 has an inlet protrusion 76a that is inserted into the insertion portion 72a from the -Z direction. The inlet manifold 76 also has an inlet base 76b that is connected to the inlet protrusion 76a from the -Z direction and is joined to the +X direction ends of the two head chips 43 and the second flow path plate 78. The inlet manifold 76 also has an internal flow path 76c. The internal flow path 76c has an open end at the +Z direction end of the inlet protrusion 76a and at the -X direction surface of the inlet base 76b.

[0074] 5, the outlet manifold 77 is joined together to the -X direction ends of the two head chips 43 and the second flow path plate 78, and is inserted into the -X direction insertion portion 72a of the first flow path plate 72. The outlet manifold 77 has an outlet protrusion 77a that is inserted into the insertion portion 72a from the -Z direction. The outlet manifold 77 also has an outlet base 77b that is connected to the outlet protrusion 77a from the -Z direction and is joined to the -X direction ends of the two head chips 43 and the second flow path plate 78. The outlet manifold 77 also has an internal flow path 77c. The internal flow path 77c has an open end at the +Z direction end of the outlet protrusion 77a and at the +X direction surface of the outlet base 77b.

[0075] The second flow path plate 78 is sandwiched between the two head chips 43 in the Y direction. The second flow path plate 78 is integrally formed from the same member. As shown in FIG. 5, the outer shape of the second flow path plate 78 is a rectangular plate with its long sides in the X direction and its short sides in the Z direction. When viewed from the Y direction, the outer shape of the second flow path plate 78 is substantially the same as the outer shape of the cover plate 49.

[0076] One head chip 43 is bonded to a first main surface 78a facing the +Y direction of the second flow path plate 78. The other head chip 43 is bonded to a second main surface 78b facing the -Y direction of the second flow path plate 78.

[0077] The second flow path plate 78 is formed from a material that is insulating and has a thermal conductivity equal to or higher than that of the cover plate 49. For example, if the cover plate 49 is formed from silicon, it is preferable that the second flow path plate 78 be formed from silicon or carbon. This makes it possible to reduce temperature variations in the cover plate 49 between each head chip 43. This reduces temperature variations in the actuator plate 48 between each head chip 43, making it possible to uniform the ink temperature. This makes it possible to uniform the ink ejection speed and improve printing stability.

[0078] The second flow path plate 78 is formed with inlet flow paths 78c each communicating with the common ink chamber 63 and outlet flow paths 78d each communicating with a circulation path 80 (described later) of the feedback plate 45. The +X-direction end of each inlet flow path 78c opens at one end surface of the second flow path plate 78 in the +X-direction. Each inlet flow path 78c is inclined so as to be positioned downward from one end surface of the second flow path plate 78 in the +X-direction toward the −X-direction, and then bends and extends linearly toward the other end side of the second flow path plate 78 in the −X-direction. The inlet flow paths 78c are connected to the inlet manifold 76 at the other end surface of the second flow path plate 78 in the +X-direction. The inlet flow paths 78c are arranged at intervals in the Y-direction between one head chip 43 and the other head chip 43.

[0079] 5, one end of each outlet flow path 78d opens at the other end surface in the -X direction of the second flow path plate 78. Each outlet flow path 78d bends downward in a crank shape from the other end surface in the -X direction of the second flow path plate 78, and then extends linearly in the +X direction. The outlet flow path 78d is connected to the outlet manifold 77 at the other end surface in the -X direction of the second flow path plate 78. The outlet flow paths 78d are arranged between one head chip 43 and the other head chip 43 at intervals in the Y direction.

[0080] 3 and 4, the heat transfer plate 79 is joined to the surface of the flow path cover 73 in the -Y direction. The heat transfer plate 79 abuts against a plurality of driving ICs 84 (described later) of the substrate unit 47 from the +Y direction. The heat transfer plate 79 thermally connects the driving ICs 84 to the flow path cover 73. As shown in FIG. 4, the heat transfer plate 79 is formed in the shape of a rectangular plate with the thickness direction in the Y direction and the longitudinal direction in the X direction. When viewed from the Y direction, the heat transfer plate 79 is arranged to overlap with the horizontal portion 72k of the first groove portion 72f.

[0081] In this embodiment, an ink flow path (hereinafter referred to as an ink flow path 100) (see FIG. 9) is provided in the flow path member 44. The ink flow path 100 is formed to include a first internal flow path 72b, a second internal flow path 72c, a third internal flow path 72d, a fourth internal flow path 72e, a first groove portion 72f, a second groove portion 72g, an internal flow path 76c, an internal flow path 77c, an inlet flow path 78c, and an outlet flow path 78d. In this embodiment, in the flow direction of ink in the ink flow path 100, the first internal flow path 72b, the first groove portion 72f, the second internal flow path 72c, the internal flow path 76c, the inlet flow path 78c, the outlet flow path 78d, the internal flow path 77c, the third internal flow path 72d, the second groove portion 72g, and the fourth internal flow path 72e are arranged in this order from the upstream side.

[0082] Fig. 9 is a schematic diagram of an inkjet head 5 including an ink flow path 100. In this embodiment, the ink flow path 100 has an inlet flow path 101, a cooling flow path 102, a connection flow path 103, a guide flow path 104, and a discharge flow path 105. In Fig. 9 and subsequent figures, the ink flow is indicated by the reference symbol L.

[0083] The inflow flow path 101 guides ink that flows into the flow path member 44 from the outside of the flow path member 44 (the ink supply pipe 21) via the inflow port 74. The inflow flow path 101 connects the inflow port 74 and the cooling flow path 102. The upstream end of the inflow flow path 101 is connected to the inflow port 74. The downstream end of the inflow flow path 101 is connected to the cooling flow path 102. In this embodiment, the inflow flow path 101 is formed to include the first internal flow path 72b (see FIG. 8), a first inlet end 72h (see FIG. 8) of the first groove portion 72f, a first vertical portion 72i (see FIG. 8) of the first groove portion 72f, and a first inclined portion 72j (see FIG. 8) of the first groove portion 72f.

[0084] The cooling flow path 102 guides ink from the -X direction (the other side) to the +X direction (one side) of the X direction (first direction) to cool the multiple driving ICs 84. The cooling flow path 102 connects the inflow flow path 101 and the connection flow path 103. The upstream end of the cooling flow path 102 is connected to the inflow flow path 101. The downstream end of the cooling flow path 102 is connected to the connection flow path 103. The cooling flow path 102 is formed to include the horizontal portion 72k of the first groove portion 72f (see FIG. 8). In this embodiment, the cooling flow path 102 is arranged so as to overlap the multiple driving ICs 84 and the heat transfer plate 79 when viewed from the Y direction.

[0085] The connection flow path 103 guides ink between the cooling flow path 102 and the guide flow path 104. The connection flow path 103 connects the cooling flow path 102 and the guide flow path 104. The upstream end of the connection flow path 103 is connected to the cooling flow path 102. The downstream end of the connection flow path 103 is connected to the guide flow path 104. The connection flow path 103 is formed to include the second vertical portion 72m (see FIG. 8) of the first groove portion 72f, the first outlet end 72n (see FIG. 8) of the first groove portion 72f, the second internal flow path 72c, and the internal flow path 76c.

[0086] The guide flow channel 104 guides ink from the +X direction (one side) to the -X direction (the other side) of the X direction. The guide flow channel 104 is connected to a plurality of ejection channels 50 (pressure chambers) of the head chip 43. The guide flow channel 104 connects the connection flow channel 103 and the discharge flow channel 105. The upstream end of the guide flow channel 104 is connected to the connection flow channel 103. The downstream end of the guide flow channel 104 is connected to the discharge flow channel 105. The guide flow channel 104 is formed to include an inlet flow channel 78c (see FIG. 5) and an outlet flow channel 78d (see FIG. 5).

[0087] As described above, the inlet flow path 78c has a portion that is inclined downward from one end face of the second flow path plate 78 in the +X direction toward the -X direction. In this portion, ink flows at an incline relative to the horizontal, flowing downward from the +X direction toward the -X direction. Furthermore, the outlet flow path 78d has a portion that is bent downward in a crank shape from the other end face of the second flow path plate 78 in the -X direction. In this portion, ink flows from the bottom to the top. However, these portions are provided in only a small portion of the inlet flow path 78c and the outlet flow path 78d. Therefore, ink in the inlet flow path 78c and the outlet flow path 78d mainly flows from the +X direction to the -X direction.

[0088] Furthermore, the guide channel 104 has an end portion in the +X direction of the inlet channel 78c connected to the connecting channel 103, and an end portion in the −X direction of the outlet channel 78d connected to the discharge channel 105. Furthermore, the head chip 43 is disposed between the inlet channel 78c and the outlet channel 78d. In other words, the guide channel 104 is a channel that primarily guides ink from the +X direction to the −X direction as a whole, but in its actual structure, it is not a simple linear channel. However, for convenience of explanation, in FIG. 9 , the guide channel 104 is schematically illustrated as a single channel, with the end portion in the +X direction connected to the connecting channel 103 and the end portion in the −X direction connected to the discharge channel 105. Note that in the drawings subsequent to FIG. 9 , the guide channel is similarly schematically illustrated as a single channel.

[0089] That is, the flow of ink in the guide flow path 104, which includes the inlet flow path 78c and the outlet flow path 78d, is mainly from the +X direction to the -X direction. Furthermore, the guide flow path 104 may include a partial ink flow in a direction different from the main flow direction. Similarly, the cooling flow path 102 may also include a partial ink flow in a direction different from the main flow direction (from the -X direction to the +X direction).

[0090] The discharge flow path 105 guides ink to be discharged to the outside of the flow path member 44 (to the ink discharge pipe 22) via the discharge port 75. The discharge flow path 105 connects the guide flow path 104 and the discharge port 75. The upstream end of the discharge flow path 105 is connected to the guide flow path 104. The downstream end of the discharge flow path 105 is connected to the discharge port 75. In this embodiment, the discharge flow path 105 is formed to include an internal flow path 77c (see FIG. 8), a third internal flow path 72d (see FIG. 8), a second groove portion 72g (see FIG. 8), and a fourth internal flow path 72e (see FIG. 8).

[0091] As described above, in this embodiment, the inflow channel 101, the guide channel 104, the cooling channel 102, and the discharge channel 105 are arranged in series in the ink channel 100. Furthermore, the inflow channel 101, the cooling channel 102, the guide channel 104, and the discharge channel 105 are arranged in this order in the ink flow direction.

[0092] Ink flowing through the ink flow path 100 is guided from the inflow port 74 to the inflow flow path 101 and then supplied to the cooling flow path 102. The ink is guided horizontally in the cooling flow path 102 from the -X direction to the +X direction. The temperature of the ink flowing through the cooling flow path 102 increases as it moves downstream (i.e., in the +X direction) due to heat exchange with the driving IC 84. The ink discharged from the cooling flow path 102 is supplied to the guide flow path 104 via the connection flow path 103. The ink is guided horizontally in the guide flow path 104 from the +X direction to the -X direction.

[0093] The temperature of head chip 43 rises due to heat generated by driving actuator plate 48. Therefore, the temperature of ink flowing through guide channel 104 rises as it moves downstream (i.e., in the −X direction) due to heat exchange with head chip 43. The ink discharged from guide channel 104 is guided to discharge port 75 via discharge channel 105.

[0094] In this way, the temperature of the ink rises in the cooling flow channel 102 and the guide flow channel 104. In this embodiment, the ink flows in the cooling flow channel 102 and the guide flow channel 104 in opposite directions. That is, the ink flows in the cooling flow channel 102 from the -X direction to the + direction, and the ink flows in the guide flow channel 104 from the +X direction to the -X direction.

[0095] [Return Plate 45] The feedback plate 45 is disposed on the open end side of the ejection channels 50 in the head chips 43. The feedback plate 45 is a spacer plate interposed between the open ends of the ejection channels 50 in one head chip 43 and the other head chip 43 and the upper end of the nozzle plate 46. The feedback plate 45 has a plurality of circulation paths 80 formed therein, which connect the ejection channels 50 of each head chip 43 to the outlet flow path 78d.

[0096] [Nozzle Plate 46] The nozzle plate 46 is bonded to the lower end surface of the feedback plate 45. The nozzle plate 46 has an array of nozzle holes 81 that penetrate the nozzle plate 46 in the Z direction. Each nozzle hole 81 communicates with a corresponding ejection channel 50 of the head chip 43 via a circulation path 80. On the other hand, each of the non-ejection channels 51 does not communicate with the nozzle hole 81 and is covered from below by the feedback plate 45 .

[0097] [PCB Unit 47] 3, the substrate unit 47 is supported on the surface of the flow path cover 73 in the -Y direction. The substrate unit 47 includes a drive substrate 82, a wiring substrate 83, and a drive IC 84 (drive control unit). The drive substrate 82 and the wiring substrate 83 are each a flexible printed circuit board, and are configured by forming a wiring pattern on a base film.

[0098] The drive substrate 82 has a mounting portion 82a and a chip connection portion 82b. The drive substrate 82 may use a rigid substrate or the like for the mounting portion 82a. The mounting portion 82a is supported by the flow path cover 73. A plurality of drive ICs 84 are mounted on the surface of the mounting portion 82a in the +Y direction. The mounting portion 82a is also connected to an interface (not shown). The interface supplies power supplied from outside the inkjet head 5 to the substrate unit 47, for example, and transmits and receives control signals.

[0099] 4, chip connection portion 82b extends in the −Z direction from mounting portion 82a. As shown in FIGS. 6 and 7, the −Z direction end of chip connection portion 82b is connected to one head chip 43.

[0100] 6 and 7, wiring board 83 connects mounting portion 82a and the other head chip 43. Specifically, the +Z direction end of wiring board 83 is connected to mounting portion 82a, and the −Z direction end is connected to the other head chip 43.

[0101] In this embodiment, five driving ICs 84 are provided. However, the number of driving ICs 84 may be two to four. Also, the number of driving ICs 84 may be six or more. These driving ICs 84 are arranged linearly in the X direction, as shown in FIG.

[0102] These drive ICs 84 drive the head chip 43. In this embodiment, a configuration will be described in which all the drive ICs 84 are mounted together on one drive board 82. However, for example, a drive board may be provided corresponding to each drive IC 84.

[0103] In the following description, the multiple driving ICs 84 arranged linearly in the X direction are referred to as the first driving IC 84a, second driving IC 84b, third driving IC 84c, fourth driving IC 84d, and fifth driving IC 84e from the -X direction to the +X direction. In other words, of the multiple driving ICs 84, the driving IC 84 located furthest in the -X direction is the first driving IC 84a, and the driving IC 84 located furthest in the +X direction is the fifth driving IC 84e.

[0104] The first drive IC 84a, the second drive IC 84b, the third drive IC 84c, the fourth drive IC 84d, and the fifth drive IC 84e are in contact with the heat transfer plate 79 from the -Y direction, and are thermally connected to the flow path member 44. That is, in this embodiment, the substrate unit 47 has a plurality of drive ICs 84 arranged along the X direction mounted thereon, and is thermally connected to the flow path member 44.

[0105] [Nozzle Guard 42] 4, the nozzle guard 42 is connected to the base member 40 from the -Z direction and covers the base member 40 from the -Z direction. The nozzle guard 42 is formed with an exposure hole 42a that exposes the nozzle plate 46 to the outside. The nozzle holes 81 described above communicate with the outside of the inkjet head 5 through the exposure hole 42a. Note that the nozzle guard 42 may be configured so that a cap is attached to the nozzle guard 42 from the -Z direction to seal the nozzle holes 81 described above when filling with ink or when the printing operation is stopped.

[0106] [How the printer works] Next, the operation method of the printer 1 when using the printer 1 to record characters, figures, etc. on the recording medium P will be described. 1 are each fully filled with ink of a different color. The ink in the ink tanks 4 is then transferred to the inkjet head 5 via the ink circulation mechanism 6.

[0107] 1, when the printer 1 is operated in the initial state, rollers 11 and 12 of the conveyance mechanisms 2 and 3 rotate, and the recording medium P is conveyed between these rollers 11 and 12 in the conveyance direction (X direction). Simultaneously with the conveyance of the recording medium P, a drive motor 35 rotates a pulley 32 to move an endless belt 34. As a result, the carriage 30 moves back and forth in the Y direction while being guided by guide rails 28 and 29. During the reciprocating movement of the carriage 30, ink of four colors is appropriately ejected from each inkjet head 5 onto the recording medium P, thereby making it possible to record characters, images, and the like on the recording medium P.

[0108] Here, the movement of each inkjet head 5 will be described. In the vertical circulation inkjet head 5 of the edge chute type as in this embodiment, the pressure pump 24 and suction pump 25 shown in FIG. 2 are first operated to circulate ink through the circulation channel 23. In this case, ink circulating through the ink supply pipe 21 flows into the first flow path plate 72 through the inlet port 74. The ink guided through the first flow path plate 72 passes through the inlet manifold 76 and flows into each inlet flow path 78c of the second flow path plate 78. The ink that flows into each inlet flow path 78c passes through each common ink chamber 63 and is then supplied to each ejection channel 50 through the slit 64. The ink that flows into each ejection channel 50 passes through the circulation path 80 of the feedback plate 45, gathers in the outlet flow path 78d, and is then supplied again to the first flow path plate 72 through the outlet manifold 77. The ink that has been supplied again to the first flow path plate 72 is discharged to the ink discharge pipe 22 through the discharge port 75. The ink discharged into the ink discharge pipe 22 is returned to the ink tank 4 and then supplied again to the ink supply pipe 21. In this way, the ink is circulated between the inkjet head 5 and the ink tank 4.

[0109] Then, when the carriage 30 (see FIG. 1) starts reciprocating, a drive voltage is applied to the common electrode 56 and the individual electrodes 58 via the substrate unit 47. At this time, the drive voltage is applied with the individual electrode 58 at drive potential Vdd and the common electrode 56 at reference potential GND. This causes thickness slip deformation in the two drive walls that define the ejection channel 50, and these two drive walls deform so as to protrude toward the non-ejection channel 51. That is, since the actuator plate 48 of this embodiment is made up of two piezoelectric substrates that are polarized in the thickness direction (Y direction) and are stacked, applying a drive voltage causes the drive walls to bend and deform in a V shape around the midpoint in the Y direction. This causes the ejection channel 50 to deform as if it were bulging.

[0110] When the volume of the ejection channel 50 increases due to the deformation of the two drive walls, the ink in the common ink chamber 63 is guided into the ejection channel 50 through the slit 64. The ink guided into the ejection channel 50 then becomes a pressure wave that propagates inside the ejection channel 50, and when this pressure wave reaches the nozzle hole 81, the drive voltage applied between the common electrode 56 and the individual electrode 58 is set to zero. As a result, the drive wall is restored to its original state, and the volume of the ejection channel 50, which had once increased, returns to its original volume. This action increases the pressure inside the ejection channel 50, pressurizing the ink. As a result, the ink can be ejected from the nozzle hole 81. At this time, the ink is ejected as liquid ink droplets as it passes through the nozzle hole 81. This makes it possible to record characters, images, etc. on the recording medium P as described above.

[0111] The method of operating the inkjet head 5 is not limited to the above. For example, the drive wall in the normal state may be configured to deform inwardly of the ejection channel 50, causing the ejection channel 50 to appear as if it were recessed inward. This can be achieved by applying a voltage between the common electrode 56 and the individual electrode 58 that is opposite in polarity to the voltage described above, or by reversing the polarization direction of the actuator plate 48 without changing the polarity of the voltage. Furthermore, the ejection channel 50 may be deformed so as to bulge outward, and then deformed so as to recess inward, thereby increasing the pressure applied to the ink during ejection.

[0112] The inkjet head 5 of this embodiment as described above includes a head chip 43, a flow path member 44, and a substrate unit 47. The head chip 43 is provided with a plurality of ejection channels 50 arranged sequentially from the +X direction to the −X direction of the X direction, and ejects ink from inside the ejection channels 50. The flow path member 44 is provided with guide flow paths 104 that guide ink from the +X direction to the −X direction of the X direction, and the guide flow paths 104 are connected to each of the ejection channels 50. The substrate unit 47 has a plurality of driving ICs 84 arranged along the X direction mounted thereon and is thermally connected to the flow path member 44. The flow path member 44 is also provided with cooling flow paths 102 that guide ink from the −X direction to the +X direction of the X direction and cool the plurality of driving ICs 84.

[0113] The inkjet head 5 has two main heat sources: the head chip 43 provided with ejection channels 50 that perform the ink ejection operation, and a plurality of drive ICs 84. According to the inkjet head 5 of this embodiment, the flow path member 44 is provided with a guide flow path 104 that is connected to the ejection channels 50 of the head chip 43, which is one of these heat sources. The flow path member 44 also has a cooling flow path 102 that cools the plurality of drive ICs 84, which are one of these heat sources.

[0114] In the guide flow channel 104 and the cooling flow channel 102, the flow direction of ink in the guide flow channel 104 is opposite to the flow direction of ink in the cooling flow channel 102 that cools the driving ICs 84. Therefore, in the guide flow channel 104, the −X side in the X direction is relatively higher in temperature than the +X side. On the other hand, in the cooling flow channel 102, the +X side in the X direction is relatively higher in temperature than the −X side.

[0115] As a result, the temperature distribution throughout the inkjet head 5 is more uniform than when the ink flow direction in the guide channel 104 and the ink flow direction in the cooling channel 102 are the same. By uniforming the overall heat distribution throughout the inkjet head 5, the temperature of the ink supplied to each ejection channel 50 is uniformed, and the viscosity of the ink in each ejection channel 50 is also uniformed. This allows for stable ejection performance. Furthermore, by uniforming the overall heat distribution throughout the inkjet head 5, the maximum temperature reached by the driving IC 84 can be reduced, allowing the driving IC 84 to be driven stably.

[0116] In the inkjet head 5 of this embodiment, the flow path member 44 is provided with an inflow flow path 101 and a discharge flow path 105. The inflow flow path 101 guides ink flowing in from the outside. The discharge flow path 105 guides ink to be discharged to the outside. The inflow flow path 101, the guide flow path 104, the cooling flow path 102, and the discharge flow path 105 are arranged in series.

[0117] According to the inkjet head 5 of this embodiment, ink supplied to the ejection channel 50 flows through the cooling channel 102. This makes it possible to prevent pressure from dispersing throughout the entire channel through which the ink flows, compared to when the guide channel 104 and the cooling channel 102 are arranged in parallel between the inlet channel 101 and the outlet channel 105. Therefore, if the pressure at the inlet of the inlet channel 101 and the outlet of the outlet channel 105 is set to the same conditions as when the guide channel 104 and the cooling channel 102 are arranged in parallel between the inlet channel 101 and the outlet channel 105, the ink flow rate increases. This makes it possible to improve the cooling efficiency in the cooling channel 102.

[0118] In the inkjet head 5 of this embodiment, the inlet flow path 101, the cooling flow path 102, the guide flow path 104, and the discharge flow path 105 are arranged in this order. Generally, the driving IC 84 becomes hotter than the head chip 43. In the inkjet head 5 of this embodiment, the ink flows through the cooling flow path 102 before the guide flow path 104. Therefore, ink at a lower temperature can be used to cool the driving IC 84 compared to when the ink that has flowed through the guide flow path 104 and has become hot is made to flow through the cooling flow path 102. This improves the cooling efficiency of the driving IC 84.

[0119] The inkjet head 5 of this embodiment also includes an inlet port 74 and an outlet port 75. The inlet port 74 is connected to the upstream end of the inlet flow path 101. The outlet port 75 is connected to the downstream end of the outlet flow path 105. The inlet port 74 and the outlet port 75 are disposed adjacent to each other on the −X direction side of the center of the flow path member 44 in the X direction.

[0120] According to the inkjet head 5 of this embodiment, it is possible to arrange the ink supply tube 21 connected to the inlet port 74 and the ink discharge tube 22 connected to the discharge port 75 close together. Therefore, the inlet port 74 and the discharge port 75 are less likely to interfere with other components than when the inlet port 74 and the discharge port 75 are arranged far apart. Furthermore, ink flows from one side to the other side in the cooling flow path 102, and ink flows from one side to the other in the guide flow path 104. Therefore, when the guide flow path 104 and the cooling flow path 102 are arranged in series, it is possible to minimize the length of the flow path through which the ink flows.

[0121] The printer 1 of this embodiment also includes the above-described inkjet head 5. This makes the printer have stable ejection performance.

[0122] (Modification of the first embodiment) 10 is a schematic diagram showing a modified example of the inkjet head 5 of the first embodiment, including an ink flow path 100. In this modified example, the flow of ink in the ink flow path 100 is opposite to that in the above-described example. That is, in this modified example, the inlet flow path 101 is used as the outlet flow path, and the outlet flow path 105 is used as the inlet flow path. Also, the inlet port 74 is used as the outlet port, and the outlet port 75 is used as the inlet port.

[0123] In the following description, the discharge flow path 105 used as an inlet flow path in this modified example will be referred to as the inlet flow path 106, and the inlet flow path 101 used as an outlet flow path in this modified example will be referred to as the outlet flow path 107. Furthermore, the discharge port 75 used as an inlet port in this modified example will be referred to as the inlet port 85, and the inlet port 74 used as an outlet port in this modified example will be referred to as the outlet port 86.

[0124] The inflow flow channel 106 guides ink that flows into the flow channel member 44 from the outside of the flow channel member 44 (the ink supply pipe 21) via the inflow port 85. The inflow flow channel 101 connects the inflow port 85 and the guide flow channel 104. The upstream end of the inflow flow channel 106 is connected to the inflow port 85. The downstream end of the inflow flow channel 106 is connected to the guide flow channel 104.

[0125] The guide channel 104 guides ink from the -X direction (one side) to the +X direction (the other side) of the X direction. The guide channel 104 connects the inflow channel 106 and the connection channel 103. The upstream end of the guide channel 104 is connected to the inflow channel 106. The downstream end of the guide channel 104 is connected to the connection channel 103.

[0126] The connecting flow channel 103 guides ink between the guide flow channel 104 and the cooling flow channel 102. The connecting flow channel 103 connects the cooling flow channel 102 and the guide flow channel 104. The upstream end of the connecting flow channel 103 is connected to the guide flow channel 104. The downstream end of the connecting flow channel 103 is connected to the cooling flow channel 102.

[0127] The cooling flow path 102 guides ink from the +X direction (the other side) to the -X direction (one side) of the X direction to cool the multiple driving ICs 84. The cooling flow path 102 connects the connection flow path 103 and the discharge flow path 107. The upstream end of the cooling flow path 102 is connected to the connection flow path 103. The downstream end of the cooling flow path 102 is connected to the discharge flow path 107.

[0128] The discharge flow path 107 guides ink to be discharged to the outside of the flow path member 44 (to the ink discharge pipe 22) via the discharge port 86. The discharge flow path 107 connects the cooling flow path 102 and the discharge port 86. The upstream end of the discharge flow path 107 is connected to the cooling flow path 102. The downstream end of the discharge flow path 107 is connected to the discharge port 86.

[0129] As described above, in this embodiment, the inflow channel 106, the guide channel 104, the cooling channel 102, and the discharge channel 107 are arranged in series in the ink channel 100. Furthermore, the inflow channel 106, the guide channel 104, the cooling channel 102, and the discharge channel 107 are arranged in this order in the ink flow direction.

[0130] According to this modification, the distance from the inflow channel 106 to the ejection channel 50 is shorter than when the cooling channel 102 is disposed between the inflow channel 106 and the guide channel 104. This reduces the pressure loss up to the ejection channel 50, suppresses a shortage of ink supply to the ejection channel 50, and enables ink to be ejected from the ejection channel 50 stably.

[0131] In this modification, the ink flow direction in the guide flow channel 104 is opposite to the ink flow direction in the cooling flow channel 102 that cools the driving ICs 84. In the guide flow channel 104, the +X side in the X direction is relatively higher in temperature than the −X side. On the other hand, in the cooling flow channel 102, the −X side in the X direction is relatively higher in temperature than the +X side.

[0132] As a result, the temperature distribution across the entire inkjet head 5 is more uniform than when the ink flow direction in the guide flow channel 104 is the same as the ink flow direction in the cooling flow channel 102. This makes it possible to obtain stable ejection performance. Also, the driving IC 84 can be driven stably.

[0133] (Second embodiment) Next, a second embodiment of the present disclosure will be described. Note that in this embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

[0134] 11 is a schematic diagram including an ink flow path 100A of an inkjet head 5A of this embodiment. In this embodiment, the ink flow path 100A has an inflow flow path 111, a partial cooling flow path 112 (second cooling flow path), a cooling flow path 113, a connection flow path 114, a guide flow path 115, and a discharge flow path 116.

[0135] The inflow flow path 111 guides ink that flows into the flow path member 44 from outside the flow path member 44 (from the ink supply pipe 21) via the inflow port 74. The inflow flow path 111 connects the inflow port 74 and the partial cooling flow path 112. The upstream end of the inflow flow path 111 is connected to the inflow port 74. The downstream end of the inflow flow path 111 is connected to the partial cooling flow path 112.

[0136] 11, the inflow passage 111 in this embodiment has a vertical passage 111a extending in the −Z direction from the inflow port 74, and a separated passage 111b (separated portion) that displaces in the +X direction as it moves from the downstream end of the vertical passage 111a toward the −Z direction. As shown in FIG. 11, the separated passage 111b is inclined with respect to the vertical direction (Z direction), and moves away from the discharge passage 116 as it moves downward (downstream). Such an inflow passage 111 can be provided, for example, by modifying the shape of the first groove portion 72f in the first embodiment and using a part of the first groove portion 72f.

[0137] The partial cooling flow path 112 is a flow path that allows ink to flow from the +X direction to the -X direction in the X direction. This partial cooling flow path 112 cools some of the multiple driving ICs 84 that are located in the -X direction. In this embodiment, as shown in FIG. 11 , the partial cooling flow path 112 is arranged to overlap the first driving IC 84a, the second driving IC 84b, and the third driving IC 84c when viewed from the Y direction, and cools the first driving IC 84a, the second driving IC 84b, and the third driving IC 84c. In other words, the partial cooling flow path 112 cools the multiple driving ICs 84 in order, starting with the driving IC 84 closest to the discharge flow path 116, and does not cool at least the driving IC 84 farthest from the discharge flow path 116.

[0138] The partial cooling flow passage 112 connects the inflow flow passage 111 and the cooling flow passage 113. The upstream end of the partial cooling flow passage 112 is connected to the inflow flow passage 111. The downstream end of the partial cooling flow passage 112 is connected to the upstream end of the cooling flow passage 113. Such a partial cooling flow passage 112 can be provided, for example, by modifying the shape of the first groove portion 72f of the first embodiment and using a part of the first groove portion 72f.

[0139] The cooling flow path 113 guides ink from the -X direction to the +X direction of the X direction to cool the multiple driving ICs 84. The cooling flow path 113 connects the partial cooling flow path 112 and the connection flow path 114. The upstream end of the cooling flow path 113 is connected to the partial cooling flow path 112. The downstream end of the cooling flow path 113 is connected to the connection flow path 114.

[0140] The connection flow channel 114 guides ink between the cooling flow channel 113 and the guide flow channel 115. The connection flow channel 114 connects the cooling flow channel 113 and the guide flow channel 115. The upstream end of the connection flow channel 114 is connected to the cooling flow channel 113. The downstream end of the connection flow channel 114 is connected to the guide flow channel 115.

[0141] The guide channel 115 guides ink from the +X direction to the -X direction of the X direction. The guide channel 115 is connected to multiple ejection channels 50 of the head chip 43. The guide channel 115 connects the connection channel 114 and the discharge channel 116. The upstream end of the guide channel 115 is connected to the connection channel 114. The downstream end of the guide channel 115 is connected to the discharge channel 116.

[0142] The discharge flow path 116 guides ink to be discharged to the outside of the flow path member 44 (to the ink discharge pipe 22) via the discharge port 75. The discharge flow path 116 connects the guide flow path 115 and the discharge port 75. The upstream end of the discharge flow path 116 is connected to the guide flow path 115. The downstream end of the discharge flow path 116 is connected to the discharge port 75.

[0143] As described above, in the inkjet head 5A of this embodiment, the inflow channel 111 has the separated channel 111b that separates from the discharge channel 116 as it moves downstream. In the inkjet head 5A of this embodiment, it is possible to prevent the temperature of the ink flowing through the inflow channel 111 from increasing due to the high-temperature ink flowing through the discharge channel 116. Therefore, it is possible to supply lower-temperature ink to the cooling channel 113 and improve the cooling efficiency of the driving IC 84 compared to a case in which the separated channel 111b is not provided.

[0144] Furthermore, in the inkjet head 5A of this embodiment, the inlet flow path 111 is provided with a partial cooling flow path 112 that allows ink to flow from the +X direction (one side) to the -X direction (the other side) of the X direction. The partial cooling flow path 112 cools some of the driving ICs 84 located in the -X direction among the multiple driving ICs 84. With this inkjet head 5A of this embodiment, it is possible to locally cool the driving ICs 84 that are located in positions that are likely to be heated by high-temperature ink flowing through the discharge flow path 116. This makes it possible to further reduce the maximum temperature that the driving ICs 84 can reach.

[0145] (Modification of the second embodiment) 12 is a schematic diagram showing a modified inkjet head 5A of the second embodiment, including an ink flow path 100A. In this modified example, the flow of ink in the ink flow path 100A is opposite to that in the above-described example. That is, in this modified example, the inlet flow path 111 is used as the outlet flow path, and the outlet flow path 116 is used as the inlet flow path. Also, the inlet port 74 is used as the outlet port, and the outlet port 75 is used as the inlet port.

[0146] In the following description, the discharge flow path 116 used as an inlet flow path in this modified example will be referred to as the inlet flow path 117, and the inlet flow path 111 used as an outlet flow path in this modified example will be referred to as the outlet flow path 118. Furthermore, the discharge port 75 used as an inlet port in this modified example will be referred to as the inlet port 85, and the inlet port 74 used as an outlet port in this modified example will be referred to as the outlet port 86.

[0147] The inflow flow path 117 guides ink that flows into the flow path member 44 from the outside of the flow path member 44 (the ink supply pipe 21) via the inflow port 85. The inflow flow path 117 connects the inflow port 85 and the guide flow path 115. The upstream end of the inflow flow path 117 is connected to the inflow port 85. The downstream end of the inflow flow path 117 is connected to the guide flow path 115.

[0148] The guide channel 115 guides ink from the -X direction (one side) to the +X direction (the other side) of the X direction. The guide channel 115 connects the inflow channel 117 and the connection channel 114. The upstream end of the guide channel 115 is connected to the inflow channel 117. The downstream end of the guide channel 115 is connected to the connection channel 114.

[0149] The connection flow channel 114 guides ink between the guide flow channel 115 and the cooling flow channel 113. The connection flow channel 114 connects the cooling flow channel 113 and the guide flow channel 115. The upstream end of the connection flow channel 114 is connected to the guide flow channel 115. The downstream end of the connection flow channel 114 is connected to the cooling flow channel 113.

[0150] The cooling flow path 113 guides ink from the +X direction (the other side) to the -X direction (one side) of the X direction to cool the multiple driving ICs 84. The cooling flow path 113 connects the connection flow path 114 and the partial cooling flow path 112. The upstream end of the cooling flow path 113 is connected to the connection flow path 114. The downstream end of the cooling flow path 113 is connected to the partial cooling flow path 112.

[0151] The partial cooling flow path 112 guides ink from the -X direction to the +X direction of the X direction to cool some of the driving ICs 84. The partial cooling flow path 112 connects the cooling flow path 113 and the discharge flow path 118. The upstream end of the partial cooling flow path 112 is connected to the cooling flow path 113. The downstream end of the partial cooling flow path 112 is connected to the discharge flow path 118.

[0152] The discharge flow path 118 guides ink to be discharged to the outside of the flow path member 44 (to the ink discharge pipe 22) via the discharge port 86. The discharge flow path 118 connects the partial cooling flow path 112 and the discharge port 86. The upstream end of the discharge flow path 118 is connected to the partial cooling flow path 112. The downstream end of the discharge flow path 118 is connected to the discharge port 86.

[0153] As described above, in this embodiment, the inflow channel 117, the guide channel 115, the cooling channel 113, and the discharge channel 118 are arranged in series in the ink flow channel 100A. Furthermore, the inflow channel 111, the guide channel 115, the cooling channel 113, and the discharge channel 118 are arranged in this order in the ink flow direction.

[0154] According to this modification, the distance from the inflow channel 117 to the ejection channel 50 is shorter than when the cooling channel 113 or the partial cooling channel 112 is disposed between the inflow channel 117 and the guide channel 115. This reduces the pressure loss up to the ejection channel 50, suppresses a shortage of ink supply to the ejection channel 50, and enables ink to be ejected from the ejection channel 50 stably.

[0155] In this modification, the ink flow direction in the guide flow path 115 is opposite to the ink flow direction in the cooling flow path 113 that cools the driving ICs 84. In the guide flow path 115, the +X side in the X direction is relatively higher in temperature than the −X side. On the other hand, in the cooling flow path 113, the −X side in the X direction is relatively higher in temperature than the +X side.

[0156] As a result, the temperature distribution across the entire inkjet head 5A is more uniform than when the ink flow direction in the guide flow path 115 is the same as the ink flow direction in the cooling flow path 113. This makes it possible to obtain stable ejection performance. Also, the driving IC 84 can be driven stably.

[0157] (Third embodiment) Next, a third embodiment of the present disclosure will be described. Note that in this embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

[0158] 13 is a schematic diagram including an ink flow path 100B of an inkjet head 5B of this embodiment. In the inkjet head 5B of this embodiment, the inlet port 74 is disposed at the end of the flow path member 44 in the +X direction, and the outlet port 75 is disposed at the end of the flow path member 44 in the -X direction.

[0159] In this embodiment, the ink flow path 100B has an inflow path 121, a first connection path 122, a cooling path 123, a second connection path 124, a guide path 125, and a discharge path 126.

[0160] The inflow flow path 121 guides ink that flows into the flow path member 44 from the outside of the flow path member 44 (the ink supply pipe 21) via the inflow port 74. The inflow flow path 121 connects the inflow port 74 to the first connection flow path 122 and the guide flow path 125. The upstream end of the inflow flow path 121 is connected to the inflow port 74. The downstream end of the inflow flow path 121 is connected to the guide flow path 125. In addition, a midpoint of the inflow flow path 121 is connected to the first connection flow path 122.

[0161] In this embodiment, the inflow flow path 121 is provided on the +Y direction side of the flow path member 44. Such an inflow flow path 121 can be formed, for example, by forming a groove portion on the surface of the first flow path plate 72 in the +Y direction and covering this groove portion with a cover.

[0162] The first connection flow path 122 connects the inflow flow path 121 and the cooling flow path 123. The upstream end of the first connection flow path 122 is connected to a midpoint of the inflow flow path 121. The downstream end of the first connection flow path 122 is bent and connected to the cooling flow path 123. Such a first connection flow path 122 mainly guides ink from the +X direction to the -X direction.

[0163] The cooling flow path 123 guides ink from the −X direction to the +X direction of the X direction to cool the multiple driving ICs 84. The cooling flow path 123 connects the first connection flow path 122 and the second connection flow path 124. The upstream end of the cooling flow path 123 is connected to the first connection flow path 122. The downstream end of the cooling flow path 123 is connected to the second connection flow path 124.

[0164] The second connection flow path 124 connects the cooling flow path 123 and the discharge flow path 126. The upstream end of the second connection flow path 124 is bent and connected to the cooling flow path 123. The downstream end of the second connection flow path 124 is connected to an intermediate portion of the discharge flow path 126. Such a second connection flow path 124 mainly guides ink from the +X direction to the -X direction.

[0165] These first connecting flow path 122, cooling flow path 123 and second connecting flow path 124 can be formed, for example, by forming a groove portion on the surface of the first flow path plate 72 in the -Y direction and covering this groove portion with a cover.

[0166] The guide channel 125 guides ink from the +X direction to the -X direction of the X direction. The guide channel 125 is connected to multiple ejection channels 50 of the head chip 43. The guide channel 125 connects the inflow channel 121 and the discharge channel 126. The upstream end of the guide channel 125 is connected to the inflow channel 121. The downstream end of the guide channel 125 is connected to the discharge channel 126.

[0167] The discharge flow path 126 guides ink to be discharged to the outside of the flow path member 44 (to the ink discharge pipe 22) via the discharge port 75. The discharge flow path 126 connects the guide flow path 125 and the second connection flow path 124 to the discharge port 75. The upstream end of the discharge flow path 126 is connected to the guide flow path 125. The downstream end of the discharge flow path 126 is connected to the discharge port 75. In addition, a midpoint of the discharge flow path 126 is connected to the second connection flow path 124.

[0168] In this embodiment, the discharge flow path 126 is provided on the +Y direction side of the flow path member 44. Such a discharge flow path 126 can be formed, for example, by forming a groove portion on the surface of the first flow path plate 72 in the +Y direction and covering this groove portion with a cover.

[0169] As described above, in the inkjet head 5B of this embodiment, the flow path member 44 is provided with the inflow flow path 121 that guides ink flowing in from the outside and the discharge flow path 126 that guides ink to be discharged to the outside. In addition, the guide flow path 125 and the cooling flow path 123 are arranged in parallel between the inflow flow path 121 and the discharge flow path 126.

[0170] According to the inkjet head 5B of this embodiment, the distance from the inflow channel 121 to the ejection channel 50 is shorter than when the cooling channel 123 is disposed between the inflow channel 121 and the guide channel 125. This reduces the pressure loss up to the ejection channel 50, suppresses a shortage of ink supply to the ejection channel 50, and enables ink to be ejected from the ejection channel 50 stably.

[0171] In the inkjet head 5B of this embodiment, the flow path member 44 is provided with a first connection flow path 122 arranged between the inflow flow path 121 and the upstream end of the cooling flow path 123, and a second connection flow path 124 arranged between the downstream end of the cooling flow path 123 and the discharge flow path 126. The first connection flow path 122 and the second connection flow path 124 guide ink from the +X direction to the −X direction in the X direction.

[0172] According to the inkjet head 5B of this embodiment, a serpentine flow path is formed, which is made up of the first connecting flow path 122, the cooling flow path 123, and the second connecting flow path 124. This allows the ink to flow over a wide range of the flow path member 44, making it possible to further uniformize the overall heat distribution of the inkjet head 5B.

[0173] (Modification of the third embodiment) 13 is a schematic diagram showing a modified ink flow path 100B of the inkjet head 5B of the third embodiment. In this modified example, the flow of ink in the ink flow path 100B is opposite to that in the above-described example. That is, in this modified example, the inlet flow path 121 is used as the outlet flow path, and the outlet flow path 126 is used as the inlet flow path. Also, the inlet port 74 is used as the outlet port, and the outlet port 75 is used as the inlet port.

[0174] In the following description, the discharge flow path 126 used as an inlet flow path in this modified example will be referred to as an inlet flow path 127, and the inlet flow path 121 used as an outlet flow path in this modified example will be referred to as an outlet flow path 128. Furthermore, the discharge port 75 used as an inlet port in this modified example will be referred to as an inlet port 85, and the inlet port 74 used as an outlet port in this modified example will be referred to as an outlet port 86.

[0175] The inflow flow path 127 guides ink that flows into the flow path member 44 from the outside (ink supply pipe 21) of the flow path member 44 via the inflow port 85. The inflow flow path 127 connects the guide flow path 125 and the second connection flow path 124 to the inflow port 85. The upstream end of the inflow flow path 127 is connected to the inflow port 85. The downstream end of the inflow flow path 127 is connected to the guide flow path 125. In addition, a midpoint of the inflow flow path 127 is connected to the second connection flow path 124.

[0176] The guide channel 125 guides ink from the -X direction to the +X direction of the X direction. The guide channel 125 connects the inflow channel 127 and the discharge channel 128. The upstream end of the guide channel 125 is connected to the inflow channel 127. The downstream end of the guide channel 125 is connected to the discharge channel 128.

[0177] The second connection flow path 124 connects the discharge flow path 126 and the cooling flow path 123. The upstream end of the second connection flow path 124 is connected to a midpoint of the discharge flow path 126. The downstream end of the second connection flow path 124 is bent and connected to the cooling flow path 123. Such a second connection flow path 124 mainly guides ink from the -X direction to the +X direction.

[0178] The cooling flow path 123 guides ink from the +X direction to the -X direction of the X direction to cool the multiple driving ICs 84. The cooling flow path 123 connects the second connection flow path 124 and the first connection flow path 122. The upstream end of the cooling flow path 123 is connected to the second connection flow path 124. The downstream end of the cooling flow path 123 is connected to the first connection flow path 122.

[0179] The first connection flow path 122 connects the cooling flow path 123 and the discharge flow path 128. The upstream end of the first connection flow path 122 is bent and connected to the cooling flow path 123. The downstream end of the first connection flow path 122 is connected to an intermediate portion of the discharge flow path 128. Such a first connection flow path 122 mainly guides ink from the -X direction to the +X direction.

[0180] The discharge flow path 128 guides ink to be discharged to the outside of the flow path member 44 (ink discharge pipe 22) via the discharge port 86. The discharge flow path 128 connects the discharge port 86 with the first connection flow path 122 and the guide flow path 125. The upstream end of the discharge flow path 128 is connected to the guide flow path 125. The downstream end of the discharge flow path 128 is connected to the discharge port 86. In addition, a midpoint of the discharge flow path 128 is connected to the first connection flow path 122.

[0181] In this modification, the distance from the inflow channel 127 to the ejection channel 50 is also shorter than when the cooling channel 123 is disposed between the inflow channel 127 and the guide channel 125. This reduces the pressure loss up to the ejection channel 50, suppresses a shortage of ink supply to the ejection channel 50, and enables ink to be ejected from the ejection channel 50 stably.

[0182] In this modification, the ink flow direction in the guide flow path 125 is opposite to the ink flow direction in the cooling flow path 123 that cools the driving ICs 84. In the guide flow path 125, the +X side in the X direction is relatively higher in temperature than the −X side. On the other hand, in the cooling flow path 123, the −X side in the X direction is relatively higher in temperature than the +X side.

[0183] As a result, the temperature distribution across the entire inkjet head 5B is more uniform than when the ink flow direction in the guide flow path 125 is the same as the ink flow direction in the cooling flow path 123. This makes it possible to obtain stable ejection performance. Also, the driving IC 84 can be driven stably.

[0184] Also in this modification, a serpentine flow path is formed, which is made up of the first connecting flow path 122, the cooling flow path 123, and the second connecting flow path 124. This allows the ink to flow over a wide area of ​​the flow path member 44, making it possible to further uniformize the overall heat distribution of the inkjet head 5B.

[0185] (Fourth embodiment) Next, a fourth embodiment of the present disclosure will be described. Note that in this embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

[0186] 15 is a schematic diagram including an ink flow path 100C of an inkjet head 5C of this embodiment. In the inkjet head 5C of this embodiment, the inlet port 74 is disposed at the end of the flow path member 44 in the +X direction, and the outlet port 75 is disposed at the end of the flow path member 44 in the -X direction.

[0187] In this embodiment, the ink flow path 100C has an inflow flow path 131, an upper connection flow path 132 (fourth connection flow path), a cooling flow path 133, a lower connection flow path 134 (third connection flow path), a guide flow path 135, and a discharge flow path 136.

[0188] The inflow flow path 131 guides ink that flows into the flow path member 44 from the outside of the flow path member 44 (the ink supply pipe 21) via the inflow port 74. The inflow flow path 131 connects the inflow port 74 and the upper connecting flow path 132. The upstream end of the inflow flow path 131 is connected to the inflow port 74. The downstream end of the inflow flow path 131 is connected to the upper connecting flow path 132.

[0189] In this embodiment, the inflow flow path 131 is provided on the +Y direction side of the flow path member 44. Such an inflow flow path 131 can be formed, for example, by forming a groove portion on the surface of the first flow path plate 72 in the +Y direction and covering this groove portion with a cover.

[0190] The upper connecting channel 132 connects the inflow channel 131 and the cooling channel 133. The upstream end of the upper connecting channel 132 is connected to the inflow channel 131. The downstream end of the upper connecting channel 132 is bent and connected to the cooling channel 133. Such an upper connecting channel 132 mainly guides ink from the +X direction to the -X direction.

[0191] The cooling flow path 133 guides ink from the -X direction to the +X direction of the X direction to cool the multiple driving ICs 84. The cooling flow path 133 connects the upper connection flow path 132 and the lower connection flow path 134. The upstream end of the cooling flow path 133 is connected to the upper connection flow path 132. The downstream end of the cooling flow path 133 is connected to the lower connection flow path 134.

[0192] The lower connection channel 134 connects the cooling channel 133 and the guide channel 135. The upstream end of the lower connection channel 134 is connected to the cooling channel 133. The downstream end of the lower connection channel 134 is connected to the guide channel 135. Such a lower connection channel 134 guides ink from the +Z direction to the -Z direction.

[0193] It is also possible to configure the lower connection flow path 134 so that ink is guided from the +X direction to the -X direction in part or the entirety of the lower connection flow path 134. In such a case, it is also possible to guide ink in the Z direction in the upper connection flow path 132.

[0194] These upper connecting flow passages 132, cooling flow passages 133 and lower connecting flow passages 134 can be formed, for example, by forming grooves on the surface of the first flow passage plate 72 in the −Y direction and covering these grooves with a cover.

[0195] The guide channel 135 guides ink from the +X direction to the -X direction in the X direction. The guide channel 135 is connected to multiple ejection channels 50 of the head chip 43. The guide channel 135 connects the lower connection channel 134 and the discharge channel 136. The upstream end of the guide channel 135 is connected to the lower connection channel 134. The downstream end of the guide channel 135 is connected to the discharge channel 136.

[0196] The discharge flow path 136 guides ink to be discharged to the outside of the flow path member 44 (ink discharge pipe 22) via the discharge port 75. The discharge flow path 126 connects the guide flow path 135 and the discharge port 75. The upstream end of the discharge flow path 136 is connected to the guide flow path 135. The downstream end of the discharge flow path 136 is connected to the discharge port 75.

[0197] In this embodiment, the discharge flow path 136 is provided on the +Y direction side of the flow path member 44. Such a discharge flow path 136 can be formed, for example, by forming a groove portion on the surface of the first flow path plate 72 in the +Y direction and covering this groove portion with a cover.

[0198] As described above, in the inkjet head 5C of this embodiment, the inflow channel 131, the cooling channel 133, the guide channel 135, and the discharge channel 136 are arranged in series. This makes it possible to prevent pressure from dispersing throughout the channels through which ink flows, compared to when the guide channel 135 and the cooling channel 133 are arranged in parallel between the inflow channel 131 and the discharge channel 136. Therefore, if the pressure at the inlet of the inflow channel 131 and the outlet of the discharge channel 136 is set to the same conditions as when the guide channel 135 and the cooling channel 133 are arranged in parallel between the inflow channel 131 and the discharge channel 136, the ink flow rate increases. This makes it possible to improve the cooling efficiency in the cooling channel 133.

[0199] Furthermore, in the inkjet head 5C of this embodiment, the flow path member 44 is provided with a lower connecting flow path 134 that connects the guide flow path 135 and the cooling flow path 133, and an upper connecting flow path 132 that is connected to an end of the cooling flow path 133 opposite to the end connected to the lower connecting flow path 134. The upper connecting flow path 132 mainly guides ink from the +X direction to the -X direction of the X direction. According to the inkjet head 5C of this embodiment, a serpentine flow path is formed that is made up of the upper connecting flow path 132, the cooling flow path 133, and the lower connecting flow path 134. This allows ink to flow over a wide area of ​​the flow path member 44, making it possible to further uniform the overall heat distribution of the inkjet head 5C.

[0200] (Modification of the fourth embodiment) 16 is a schematic diagram showing a modified ink flow path 100C of the inkjet head 5C of the fourth embodiment. In this modified example, the flow of ink in the ink flow path 100C is opposite to that in the above-described example. That is, in this modified example, the inlet flow path 131 is used as the outlet flow path, and the outlet flow path 136 is used as the inlet flow path. Also, the inlet port 74 is used as the outlet port, and the outlet port 75 is used as the inlet port.

[0201] In the following description, the discharge flow path 136 used as an inlet flow path in this modified example will be referred to as an inlet flow path 137, and the inlet flow path 131 used as an outlet flow path in this modified example will be referred to as an outlet flow path 138. Furthermore, the discharge port 75 used as an inlet port in this modified example will be referred to as an inlet port 85, and the inlet port 74 used as an outlet port in this modified example will be referred to as an outlet port 86.

[0202] The inflow flow path 137 guides ink that flows into the flow path member 44 from the outside of the flow path member 44 (the ink supply pipe 21) via the inflow port 85. The inflow flow path 137 connects the inflow port 85 and the guide flow path 135. The upstream end of the inflow flow path 137 is connected to the inflow port 85. The downstream end of the inflow flow path 137 is connected to the guide flow path 135.

[0203] The guide channel 135 guides ink from the -X direction to the +X direction of the X direction. The guide channel 135 is connected to multiple ejection channels 50 of the head chip 43. The guide channel 135 connects the inflow channel 137 and the lower connecting channel 134. The upstream end of the guide channel 135 is connected to the inflow channel 137. The downstream end of the guide channel 135 is connected to the lower connecting channel 134.

[0204] The lower connection channel 134 connects the guide channel 135 and the cooling channel 133. The upstream end of the lower connection channel 134 is connected to the guide channel 135. The downstream end of the lower connection channel 134 is connected to the cooling channel 133. Such a lower connection channel 134 guides ink from the -Z direction to the +Z direction.

[0205] The cooling flow path 133 guides ink from the +X direction to the -X direction of the X direction to cool the multiple driving ICs 84. The cooling flow path 133 connects the lower connection flow path 134 and the upper connection flow path 132. The upstream end of the cooling flow path 123 is connected to the lower connection flow path 134. The downstream end of the cooling flow path 133 is connected to the upper connection flow path 132.

[0206] The upper connection channel 132 connects the cooling channel 133 and the inflow channel 131. The upstream end of the upper connection channel 132 is bent and connected to the cooling channel 133. The downstream end of the upper connection channel 132 is connected to the inflow channel 131. Such an upper connection channel 132 mainly guides ink from the −X direction to the +X direction.

[0207] The discharge flow path 138 guides ink to be discharged to the outside of the flow path member 44 (to the ink discharge pipe 22) via the discharge port 86. The discharge flow path 138 connects the discharge port 86 and the upper connecting flow path 132. The upstream end of the discharge flow path 138 is connected to the upper connecting flow path 132. The downstream end of the discharge flow path 138 is connected to the discharge port 86.

[0208] According to this modification, the distance from the inflow channel 137 to the ejection channel 50 is shorter than when the upper connecting channel 132, the cooling channel 133, and the lower connecting channel 134 are arranged between the inflow channel 137 and the guide channel 135. This reduces the pressure loss up to the ejection channel 50, suppresses a shortage of ink supply to the ejection channel 50, and enables ink to be ejected from the ejection channel 50 stably.

[0209] In this modification, the ink flow direction in the guide flow path 135 is opposite to the ink flow direction in the cooling flow path 133 that cools the driving ICs 84. In the guide flow path 135, the +X side in the X direction is relatively higher in temperature than the −X side. On the other hand, in the cooling flow path 133, the −X side in the X direction is relatively higher in temperature than the +X side.

[0210] As a result, the temperature distribution across the entire inkjet head 5C is more uniform than when the ink flow direction in the guide flow path 135 is the same as the ink flow direction in the cooling flow path 133. This makes it possible to obtain stable ejection performance. Also, the driving IC 84 can be driven stably.

[0211] Also in this modification, a serpentine flow path is formed, which is made up of the upper connecting flow path 132, the cooling flow path 133, and the lower connecting flow path 134. This allows the ink to flow over a wide area of ​​the flow path member 44, making it possible to further uniformize the overall heat distribution of the inkjet head 5C.

[0212] The technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, in the above-described embodiment, the printer 1 has been described as an example of a liquid ejecting apparatus, but the liquid ejecting apparatus is not limited to a printer. For example, a fax machine, an on-demand printing machine, or the like may also be used. In the above-described embodiment, a configuration in which the inkjet head moves relative to the recording medium during printing (a so-called shuttle machine) has been described as an example, but the present disclosure is not limited to this configuration. The configuration according to the present disclosure may also be employed in a configuration in which the inkjet head is fixed and the recording medium moves relative to the inkjet head (a so-called fixed head machine). In the above-described embodiment, the recording medium P is paper, but this is not limiting. The recording medium P is not limited to paper, and may be a metal material, a resin material, or a food product. In the above-described embodiment, a configuration in which the liquid jet head is mounted on a liquid jet recording apparatus has been described, but the present invention is not limited to this configuration. That is, the liquid jetted from the liquid jet head is not limited to the liquid that lands on a recording medium, but may be, for example, a medicinal liquid to be mixed into a medicine, a food additive such as a seasoning or flavoring to be added to food, or an aromatic to be sprayed into the air.

[0213] Furthermore, in the above-described embodiment, an edge-chute head chip has been described, but the present disclosure is not limited to this. For example, the present disclosure may be applied to a so-called side-chute type head chip that ejects ink from the center of the ejection channel in the extension direction. The present disclosure may also be applied to a so-called roof chute type head chip in which the direction of pressure applied to ink and the direction of ink ejection are the same.

[0214] In the above-described embodiment, the Z direction coincides with the direction of gravity, but the invention is not limited to this configuration, and the Z direction may be aligned with the horizontal direction. In the above-described embodiment, a configuration in which two head chips are mounted on one jet module has been described, but the present invention is not limited to this configuration. In other words, a configuration in which one head chip is mounted on one jet module may also be used.

[0215] In the above-described embodiment, a configuration has been described in which a portion of the ink discharged from the ink tank is returned to the ink tank, i.e., a configuration in which the ink is circulated. However, a configuration in which the ink discharged from the ink tank and supplied to the head chip does not return to the ink tank is also possible.

[0216] In addition, within the scope of the present disclosure, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and it is also possible to combine the above-described modified examples as appropriate. [Explanation of symbols]

[0217] 1. Printer (liquid jet recording device) 5. Inkjet head (liquid jet head) 5A Inkjet head (liquid jet head) 5B Inkjet head (liquid jet (liquid jet head) head) 5C inkjet head 43 Head tip (jet part) 44 Flow path member 47 Board unit (circuit board) 50 discharge channel (pressure chamber) 74 Inlet Port 75 exhaust port 84 Drive IC (drive control unit) 85 Inlet port 86 Exhaust port 100 Ink flow path 100A ink flow path 100B ink flow path 100C ink flow path 101 Inlet channel 102 Cooling channel 103 Connecting Channel 104 Guide channel 105 Discharge flow path 106 Inlet Channel 107 Discharge flow path 111 Inflow channel 111a Downstream channel 111b Separation channel (separation section) 112 Partial cooling channel (second cooling channel) 113 Cooling Channel 114 Connecting Channel 115 Guide channel 116 Discharge flow path 117 Inflow channel 118 Discharge flow path 121 Inflow channel 122 First connecting channel 123 Cooling Channel 124 Second connecting channel 125 Guide channel 126 Discharge flow path 127 Inlet Channel 128 Discharge flow path 131 Inflow channel 132 Upper connecting channel (fourth connecting channel) 133 Cooling Channel 134 Lower connecting channel (third connecting channel) 135 Guide channel 136 Discharge flow path 137 Inflow Channel 138 Discharge flow path

Claims

1. an ejection unit provided with a plurality of pressure chambers arranged sequentially from one side to the other side in a first direction, and configured to eject liquid from the pressure chambers; a flow path member provided with a guide flow path that guides liquid from the one side to the other side in the first direction, the guide flow path being connected to each of the pressure chambers; a circuit board on which a plurality of drive control units arranged along the first direction are mounted and which is thermally connected to the flow path member, the flow path member is provided with a cooling flow path that guides the liquid from the other side to the one side in the first direction to cool the plurality of drive control units, the flow path member is provided with an inflow flow path that guides the liquid flowing in from the outside and a discharge flow path that guides the liquid to be discharged to the outside, the guide flow path and the cooling flow path are arranged in parallel between the inlet flow path and the outlet flow path, an inlet port connected to an upstream end of the inlet flow path and an outlet port connected to a downstream end of the outlet flow path; The inlet port and the outlet port are disposed adjacent to each other on the one side or the other side of the center of the flow path member in the first direction. Liquid injection head.

2. the flow path member is provided with a first connecting flow path arranged between the inflow flow path and an upstream end of the cooling flow path, and a second connecting flow path arranged between the downstream end of the cooling flow path and the discharge flow path, The first connection flow path and the second connection flow path guide the liquid from the one side to the other side in the first direction. The liquid jet head according to claim 1 .

3. the flow path member is provided with an inflow flow path that guides the liquid flowing in from the outside and a discharge flow path that guides the liquid to be discharged to the outside, The inlet flow passage, the guide flow passage, the cooling flow passage, and the exhaust flow passage are arranged in series.

3. The liquid jet head according to claim 1.

4. The liquid jet head according to claim 3 , wherein the inlet flow passage, the cooling flow passage, the guide flow passage, and the outlet flow passage are arranged in this order.

5. The liquid jet head according to claim 3 , wherein the inlet flow passage, the guide flow passage, the cooling flow passage, and the outlet flow passage are arranged in this order.

6. the flow path member is provided with a third connection flow path connecting the guide flow path and the cooling flow path, and a fourth connection flow path connected to an end of the cooling flow path opposite to an end connected to the third connection flow path, At least one of the third connection flow path and the fourth connection flow path guides the liquid from the one side to the other side in the first direction at least in a portion thereof.

6. The liquid jet head according to claim 4.

7. 7. The liquid jet head according to claim 1, wherein the inlet flow path has a separation portion that separates from the outlet flow path as it goes downstream.

8. an ejection unit provided with a plurality of pressure chambers arranged sequentially from one side to the other side in a first direction, and configured to eject liquid from the pressure chambers; a flow path member provided with a guide flow path that guides liquid from the one side to the other side in the first direction, the guide flow path being connected to each of the pressure chambers; a circuit board on which a plurality of drive control units arranged along the first direction are mounted and which is thermally connected to the flow path member, the flow path member is provided with a cooling flow path that guides the liquid from the other side to the one side in the first direction to cool the plurality of drive control units, the flow path member is provided with an inflow flow path that guides the liquid flowing in from the outside and a discharge flow path that guides the liquid to be discharged to the outside, the guide flow path and the cooling flow path are arranged in parallel between the inlet flow path and the outlet flow path, the flow path member is provided with a second cooling flow path through which the liquid flows from one side to the other side in the first direction, The second cooling flow path cools some of the drive control units located on the other side among the plurality of drive control units. Liquid injection head.

9. A liquid jet recording apparatus comprising the liquid jet head according to any one of claims 1 to 8.

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