Liquid jet head, and liquid jet device

Abstract

To provide a liquid jet head and a liquid jet device which can reduce possibility of warpage caused by heat of a member constituting the liquid jet head.SOLUTION: A liquid jet head includes five or more of head chips arranged in a zigzag manner along a first direction, and a support member which supports the plurality of head chips. The plurality of head chips are arranged so as to have an overlapping area in which a part of a nozzle forming area of the one head chip out of adjacent head chips and a part of a nozzle forming area of the other head chip overlap when viewed from a second direction orthogonal to the first direction. The plurality of overlapping areas include a first overlapping area, and a second overlapping area which is farther in the first direction than the first overlapping area from a center position regarding the first direction of all nozzle forming areas consisting of all of the nozzle forming areas of the plurality of head chips. The second overlapping area is larger than the first overlapping area in regard to the first direction.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] 2. Description of the Related Art Liquid ejection apparatuses equipped with liquid ejection heads that eject liquid such as ink onto a medium such as printing paper have been proposed.

[0003] The liquid jet head described in Patent Document 1 includes a plurality of head units (corresponding to head chips) arranged in a staggered pattern, a fixing plate, and a case member (corresponding to a frame). The plurality of head units are housed and supported in a space formed by the fixing plate and the frame. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-489 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the liquid jet head described in Patent Document 1, adjacent head chips among the multiple head chips have overlapping regions where they overlap each other. In this document, the multiple head chips are arranged in a staggered pattern, and five or more overlapping regions exist.

[0006] When five or more head chips are arranged in a staggered pattern in a predetermined direction as in the document, the liquid jet head becomes longer in the predetermined direction. In addition, the head chip arranged in the center in the predetermined direction is adjacent to four head chips, so that the temperature of the center of the liquid jet head becomes higher than that of the end sides due to heat generation from the five or more head chips. As a result, a temperature difference occurs in the liquid jet head, and there is a risk that the members constituting the liquid jet head will be affected by warping. [Means for solving the problem]

[0007] A liquid ejection head according to one embodiment of the present disclosure comprises a plurality of head chips, five or more, arranged in a staggered pattern along a first direction, and a support member supporting the plurality of head chips, wherein the plurality of head chips are arranged such that a portion of a nozzle forming region of one of adjacent head chips overlaps a portion of a nozzle forming region of the other head chip when viewed in a second direction perpendicular to the first direction, and the plurality of overlapping regions include a first overlapping region and a second overlapping region that is farther in the first direction than the first overlapping region from a center position in the first direction of a total nozzle forming region formed by all the nozzle forming regions of the plurality of head chips, and the second overlapping region is larger in the first direction than the first overlapping region.

[0008] A liquid ejecting apparatus according to an aspect of the present disclosure includes a liquid ejecting head that ejects liquid onto a medium, and a transport unit that transports the medium. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a liquid ejecting apparatus according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the liquid ejection head shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line aa in FIG. [Figure 4] FIG. 2 is a top view of the liquid jet head according to the first embodiment. [Diagram 5] 5 is a cross-sectional view taken along line AA in FIG. 4. [Figure 6] 2 is a schematic diagram of a bottom surface of the liquid jet head according to the first embodiment. FIG. [Figure 7] FIG. 2 is a bottom view of the liquid jet head according to the first embodiment. [Figure 8] FIG. 4 is a bottom view of a liquid jet head of a comparative example. [Figure 9] 13 is a diagram showing the overlapping number of nozzles from which ink droplets are ejected in a first overlapping region. FIG. [Figure 10] 13 is a diagram showing the overlapping number of nozzles from which ink droplets are ejected in the second overlapping region. FIG. [Figure 11] 11 is a bottom view of a liquid jet head according to a first modified example. FIG. [Figure 12] 13 is a bottom view of a liquid jet head according to a second modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions, and some parts are shown diagrammatically to facilitate understanding. In addition, the scope of the present disclosure is not limited to these forms unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0011] In the following description, the mutually intersecting X-axis, Y-axis, and Z-axis are used as appropriate. Moreover, one direction along the X-axis is referred to as the X1 direction, and the direction opposite to the X1 direction is referred to as the X2 direction. Similarly, the opposite directions along the Y-axis are referred to as the Y1 direction and the Y2 direction. Moreover, the opposite directions along the Z-axis are referred to as the Z1 direction and the Z2 direction. The Y1 direction or the Y2 direction is an example of a "first direction," and the X1 direction or the X2 direction is an example of a "second direction." Hereinafter, viewing from the Z1 direction or the Z2 direction is referred to as a "planar view."

[0012] Typically, the Z axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z axis does not have to be a vertical axis. Also, the X axis, the Y axis, and the Z axis are typically perpendicular to each other, but are not limited to this, and may intersect at an angle within a range of 80° to 100°, for example.

[0013] 1. First embodiment 1-1. Schematic configuration of the liquid ejection device 100 1 is a schematic diagram showing an example of the configuration of a liquid ejection device 100 according to a first embodiment. The liquid ejection device 100 is an inkjet printing device that ejects ink, which is an example of a liquid, as droplets onto a medium M. The medium M is typically printing paper. Note that the medium M is not limited to printing paper, and may be a printing target made of any material, such as a resin film or fabric.

[0014] As shown in FIG. 1, the liquid ejecting device 100 includes a liquid container 10, a control unit 20, a conveying section 50, and a liquid ejecting head 30. The liquid ejecting head 30 includes a liquid container 10 and a control unit 20.

[0015] The liquid container 10 is a container that stores ink. Specific examples of the liquid container 10 include a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack made of a flexible film, and an ink tank that can be refilled with ink. The type of ink stored in the liquid container 10 is not particularly limited and may be any type.

[0016] The control unit 20 controls the operation of each element of the liquid ejection device 100. The control unit 20 includes, for example, a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage circuit such as a semiconductor memory, and controls the operation of each element of the liquid ejection device 100.

[0017] The transport unit 50 transports the medium M in a direction DM under the control of the control unit 20. The direction DM in this embodiment is the X1 direction. In the example shown in FIG. 1, the transport unit 50 includes a long transport roller along the Y axis and a motor that rotates the transport roller. Note that the transport unit 50 is not limited to a configuration using a transport roller, and may be configured to use, for example, a drum or an endless belt that transports the medium M while adsorbing it to its outer circumferential surface by electrostatic force or the like.

[0018] The liquid jet head 30 jets ink supplied from the liquid container 10 from each of the multiple nozzles N onto the medium M in the Z2 direction under the control of the control unit 20. The liquid jet head 30 is a line head that is long in the direction in which the Y axis extends. The liquid jet head 30 has multiple head chips 3 that are arranged so that the multiple nozzles N are distributed over the entire range of the medium M in the direction along the Y axis. An ink image is formed on the surface of the medium M by jetting ink from the liquid jet head 30 in parallel with the transport of the medium M by the transport unit 50.

[0019] The number and arrangement of the head chips 3 of the liquid jet head 30 are not limited to the example shown in Fig. 1 and may be arbitrary. In addition, when the liquid jet head 30 is configured to be capable of circulating ink, the liquid jet head 30 may be connected to the liquid container 10 via a circulation mechanism for circulating the ink in the liquid jet head 30.

[0020] The liquid ejection device 100 includes a liquid ejection head 30 that ejects ink onto a medium M, and a transport unit 50 that transports the medium M. As will be described later, the temperature difference in the liquid ejection head 30 is made uniform, thereby reducing the risk of warping of the members that constitute the liquid ejection head 30. Therefore, the liquid ejection device 100 including the liquid ejection head 30 can suppress deterioration in print quality.

[0021] 1-2. Overall configuration of head chip 3 Fig. 2 is an exploded perspective view of the head chip 3 shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line aa in Fig. 2. The cross section shown in Fig. 3 is a cross section parallel to the XZ plane. The Z axis is an axis line along the direction in which ink is ejected by the liquid ejection head 30.

[0022] As illustrated in FIG. 2, the head chip 3 has a plurality of nozzles N arranged along the Y axis. The plurality of nozzles N are divided into nozzle rows La and nozzle rows Lb arranged side by side at intervals along the X axis. Each of the nozzle rows La and nozzle rows Lb is a collection of a plurality of nozzles N arranged linearly along the Y axis. The liquid ejecting head 30 has a structure in which elements related to each nozzle N of the nozzle row La and elements related to each nozzle N of the nozzle row Lb are arranged in a substantially plane-symmetrical manner. In the following description, the elements corresponding to the nozzle row La will be described primarily, and descriptions of elements corresponding to the nozzle row Lb will be omitted as appropriate. In the following description, when there is no need to distinguish between the nozzle rows La and the nozzle rows Lb, they will be referred to as the nozzle row L.

[0023] As illustrated in FIGS. 2 and 3, the head chip 3 includes a communication plate 31, a pressure chamber substrate 32, a vibration plate 33, a nozzle plate 37, a vibration absorber , a plurality of drive elements , a sealing substrate 35, a housing portion and a wiring substrate .

[0024] The communicating plate 31, the pressure chamber substrate 32, the vibration plate 33, the nozzle plate 37, and the vibration absorber 38 are each a long plate-like member extending along the Y axis. The pressure chamber substrate 32 and the housing part 36 are disposed on the surface of the communicating plate 31 facing in the Z2 direction. The nozzle plate 37 and the vibration absorber 38 are disposed on the surface of the communicating plate 31 facing in the Z1 direction. For example, the respective members are fixed together by an adhesive.

[0025] The nozzle plate 37 is a plate-like member in which a plurality of nozzles N are formed. Each of the plurality of nozzles N is a circular through-hole that ejects ink. For example, the nozzle plate 37 is manufactured by processing a single crystal substrate of silicon (Si) using semiconductor manufacturing techniques such as photolithography and etching.

[0026] The communication plate 31 is formed with a plurality of throttle portions 312, a plurality of communication channels 314, a communication space Ra, and a common channel Rb. Each of the throttle portions 312 and the communication channels 314 extends in the Z1 direction and is a through hole formed for each nozzle N. The communication channel 314 overlaps the nozzle N in a plan view. The communication space Ra is an opening formed in an elongated shape along the Y axis. The communication space Ra extends along the Y axis. The common channel Rb communicates with the communication space Ra and overlaps with the communication space Ra in a plan view. The common channel Rb extends along the Y axis. The common channel Rb communicates with the plurality of throttle portions 312. In addition, the communication space Ra communicates the common channel Rb with an external channel of the head chip 3 via a space Rc and a supply port 361 described later.

[0027] A plurality of pressure chambers C1 are formed in the pressure chamber substrate 32. The pressure chamber C1 is a space located between the communication plate 31 and the vibration plate 33 and formed by the wall surface 320 of the pressure chamber substrate 32. A pressure chamber C1 is formed for each nozzle N. The pressure chamber C1 is an elongated space extending in the X1 direction. The plurality of pressure chambers C1 are arranged along the Y axis. One end of the pressure chamber C1 in the X1 direction is connected to the nozzle N via a communication flow path 314. The other end of the pressure chamber C1 in the X1 direction is connected to a throttle portion 312. The throttle portion 312 has a smaller cross-sectional area than the pressure chamber C1. An individual flow path for each nozzle N is formed by the pressure chamber C1, the nozzle N, the communication flow path 314, and the throttle portion 312.

[0028] The communication plate 31 and the pressure chamber substrate 32 are manufactured by processing a semiconductor substrate such as a silicon single crystal substrate.

[0029] An elastically deformable vibration plate 33 is disposed above the pressure chamber C1. The vibration plate 33 is laminated on the pressure chamber substrate 32 and contacts the surface of the pressure chamber substrate 32 opposite to the communicating plate 31. The vibration plate 33 is a plate-like member formed in a long rectangular shape along the Y axis in a plan view. The thickness direction of the vibration plate 33 is parallel to the Z1 direction. The pressure chamber C1 communicates with the communicating flow path 314 and the throttle portion 312. Therefore, the pressure chamber C1 communicates with the nozzle N via the communicating flow path 314, and communicates with the communicating space Ra via the throttle portion 312. Note that, for ease of explanation, the pressure chamber substrate 32 and the vibration plate 33 are illustrated in FIG. 2 as separate substrates, but in reality, they are laminated on a single silicon substrate.

[0030] A driving element 34 is formed for each pressure chamber C1 on the surface of the vibration plate 33 opposite to the pressure chamber C1. The driving element 34 is an elongated piezoelectric element extending along the X-axis in a plan view. The driving element 34 includes, for example, a pair of electrodes and a piezoelectric body sandwiched between the pair of electrodes. The driving element 34 may be an electrothermal conversion element that generates thermal energy.

[0031] The housing 36 is a case for storing ink to be supplied to the multiple pressure chambers C1, and is formed by, for example, injection molding of a resin material. A space Rc and a supply port 361 are formed in the housing 36. The supply port 361 is a conduit through which ink is supplied from the liquid container 10, and communicates with the space Rc. The space Rc of the housing 36 and the communication space Ra of the communication plate 31 communicate with each other. The communication space Ra, the common flow path Rb, and the space Rc described above form a common space R that is common to the multiple nozzles N. The common space R functions as a liquid storage chamber that stores ink to be supplied to the multiple pressure chambers C1. The ink stored in the common space R branches off to each throttle section 312 and is supplied to and filled in parallel with the multiple pressure chambers C1.

[0032] The vibration absorber 38 is a flexible film that constitutes the wall surface of the communication space Ra, and absorbs pressure fluctuations of the ink in the common space R. The vibration absorber 38 is, for example, a laminate of an ink-resistant resin film, a SUS (stainless steel) member that holds the resin film and has spring properties, and a fixed plate that protects the resin film and the SUS member. By providing the vibration absorber 38, the natural frequency of the flow path from the nozzle N through the pressure chamber C1 to the throttle section 312 is stabilized regardless of the nozzle N that is driven.

[0033] A frame 56 is bonded to the surface of the vibration absorber 38 facing the Z1 direction by an adhesive or the like. The frame 56 is a frame-shaped member that fits along the outer periphery of the vibration absorber 38. The frame 56 is made of, for example, a metal material. A fixing plate 532 (described later) is bonded to the surface of the frame 56 facing the Z1 direction by an adhesive or the like, as indicated by the two-dot chain line in the drawing.

[0034] The sealing substrate 35 is a structure that protects the multiple driving elements 34 and reinforces the mechanical strength of the pressure chamber substrate 32 and the vibration plate 33, and is fixed to the surface of the vibration plate 33 with, for example, an adhesive. The multiple driving elements 34 are housed inside a recess formed on the surface of the sealing substrate 35 facing the vibration plate 33. The wiring board 40 is inserted into a through hole 362 of the housing part 36 and a through hole 353 of the sealing substrate 35. The wiring board 40 is bonded to the surface of the vibration plate 33. The wiring board 40 is a mounting component on which multiple wirings for electrically connecting the control unit 20 and the head chip 3 are formed. The wiring board 40 includes a driving IC 41. The driving IC 41 is a circuit including a switching element that selects whether or not to supply the driving signal Com to the driving element 34. For example, a TCP (Tape Carrier Package) or an FPC (Flexible Printed Circuit) is used as the wiring board 40. A drive signal and a reference voltage for driving the drive elements 34 are supplied to each drive element 34 from the wiring board 40. Although not shown, at least a part of the drive IC 41 is located inside a through hole (not shown) through which the wiring board 40 is inserted and which is formed in the flow path structure 52 and the frame portion 531.

[0035] 5, the liquid jet head 30 has an intermediate board 70 that is long in the Y1 direction and to which the multiple wiring boards 40 are electrically connected. A connector 71 is provided on the intermediate board 70, and the control unit 20 and the intermediate board 70 are electrically connected via the connector 71 by a wiring member (not shown).

[0036] In this head chip 3, when the driving element 34 contracts due to energization, the vibration plate 33 is bent and deflected in a direction that reduces the volume of the pressure chamber C1, and the pressure inside the pressure chamber C1 rises, causing an ink droplet to be ejected from the nozzle N. At this time, pressure also propagates from the pressure chamber C1 toward the throttle portion 312, and ink also flows into the common flow path Rb through the throttle portion 312. After the ink is ejected, the driving element 34 returns to its original position. At this time, the ink in the common flow path Rb from the nozzle N also vibrates. Then, at the same time that the meniscus of the nozzle N returns to its original state, ink is supplied from the throttle portion 312. Through the above series of operations, ink is ejected from the nozzle N.

[0037] 1-3. Liquid jet head 30 Fig. 4 is a top view of liquid jet head 30 of the first embodiment. Fig. 5 is a cross-sectional view taken along line AA in Fig. 4. Fig. 6 is a schematic view of the bottom surface of liquid jet head 30 of the first embodiment. Figs. 4, 5, and 6 diagrammatically show liquid jet head 30 having head chips 3-1 to 3-7. Each of head chips 3-1 to 3-7 is the head chip 3 described above. Hereinafter, each of head chips 3-1 to 3-7 may be referred to as head chip 3.

[0038] The liquid jet head 30 includes head chips 3-1 to 3-7, a flow path structure 52, and a support member 53.

[0039] Head chips 3-1 to 3-7 are arranged in a staggered pattern along the Y2 direction when viewed along the Z axis. Head chips 3-1, 3-3, 3-5, and 3-7 are arranged in a line in the Y2 direction in this order. Head chips 3-1, 3-3, 3-5, and 3-7 are arranged so that their positions are aligned with each other in the direction along the X axis. Head chips 3-2, 3-4, and 3-6 are arranged in a line in the Y2 direction in this order. Head chips 3-2, 3-4, and 3-6 are arranged at positions in the X2 direction lower than head chips 3-1, 3-3, 3-5, and 3-7, so that their positions are aligned with each other in the direction along the X axis.

[0040] The flow path structure 52 is a structure in which a flow path Pa is provided for supplying ink from the liquid container 10 to the plurality of head chips 3. The flow path structure 52 is made of, for example, a resin material or a metal material. The flow path structure 52 is provided with a plurality of pipe sections 52d. Each of the plurality of pipe sections 52d protrudes from the flow path structure 52 in the Z1 direction.

[0041] The flow path Pa has a common flow path Pa1, a plurality of branch flow paths Pa2, and a plurality of openings HL. The common flow path Pa1 and the plurality of branch flow paths Pa2 are formed in the flow path structure 52. The plurality of openings HL are formed in a one-to-one correspondence with the plurality of pipe portions 52d.

[0042] The common flow path Pa1 is a flow path provided in common to multiple head chips 3. Specifically, the common flow path Pa1 is composed of a flow path provided in common to head chips 3-1, 3-3, 3-5, and 3-7, and a flow path provided in common to head chips 3-2, 3-4, and 3-6. Each of these flow paths extends in the direction along the Y axis, and both ends of each flow path communicate with an opening HL facing in the Z2 direction. Ink is introduced from the liquid container 10 into the opening HL.

[0043] The branch flow paths Pa2 are provided for each of the supply ports 361 of the head chips 3-1 to 3-7. Each of the branch flow paths Pa2 communicates with the corresponding supply port 361.

[0044] Support member 53 is a member that directly and commonly supports a plurality of head chips 3. Support member 53 is disposed on a surface of flow path structure 52 facing the Z1 direction, and is connected to flow path structure 52. Support member 53 includes a frame portion 531 and a fixing plate 532.

[0045] Frame portion 531 has a plurality of recesses 53a that accommodate a plurality of head chips 3. The plurality of recesses 53a are depressions provided on a surface of frame portion 531 facing the Z1 direction. Note that the plurality of recesses 53a may be provided for each head chip 3, or may be provided for each group of two or more head chips 3. For example, the plurality of recesses 53a are formed by dividing one recess into a plurality of sections.

[0046] Fixing plate 532 is disposed on a surface of frame portion 531 facing direction Z1, and is connected to frame portion 531. Fixing plate 532 is a plate-like member for fixing a plurality of head chips 3. Head chips 3 are accommodated in an accommodating space defined by fixing plate 532 and recesses 53a of frame portion 531.

[0047] The fixed plate 532 is provided with a plurality of exposure openings 53b that expose the nozzle plate 37 of each head chip 3 to the outside of the liquid ejection head 30. Each exposure opening 53b is a hole formed in the fixed plate 532. The plurality of exposure openings 53b are individually provided for each head chip 3. Each exposure opening 53b exposes a plurality of nozzles of the nozzle plate 37 of each head chip 3. The surface of the fixed plate 532 of the liquid ejection head 30 facing the Z1 direction constitutes an ejection surface FN together with the nozzle plate 37 exposed from the exposure openings 53b. As shown in FIG. 3, in this embodiment, the exposure openings 53b are formed so as to overlap with the plurality of nozzles N of the nozzle plate 37. A part of the fixed plate 532 overlaps with the outer peripheral portion of the nozzle plate 37 when viewed in the Z1 direction. The exposure openings 53b may overlap with the entire area of ​​the nozzle plate 37 in a plan view. That is, the entire nozzle plate 37 may be exposed from the exposure openings 53b.

[0048] The support member 53 is made of, for example, a metal material such as stainless steel, titanium, or magnesium alloy, or a resin material. The fixed plate 532 and the frame 531 are made of separate members, but may be integrally formed. A part of the support member 53 may be integrally formed with the flow path structure 52. For example, the frame 531 may be integrally formed with the flow path structure 52.

[0049] 1-4. Overlapping area of ​​head chip 3 FIG. 7 is a bottom view of the liquid jet head 30 according to the first embodiment.

[0050] As shown in FIG. 7, the ejection surface FN of the liquid ejection head 30 includes a total nozzle forming region S30 consisting of all the nozzle forming regions S3 of the multiple head chips 3. The nozzle forming region S3 is a region from the nozzle N arranged at one end in the Y1 direction to the nozzle N arranged at the other end among the multiple nozzles N formed in one head chip 3. In FIG. 7, the nozzles N are not illustrated, and only the nozzle forming region S3 is illustrated. Moreover, the total nozzle forming region S30 is a region from the end of the nozzle forming region S3 of the head chip 3-1 in the Y1 direction to the end of the nozzle forming region S3 of the head chip 3-7 in the Y2 direction with respect to the Y1 direction. Moreover, in this embodiment, the sizes of the nozzle forming regions S3 of the multiple head chips 3, that is, the lengths in the direction along the Y axis, are approximately the same as each other. Note that approximately the same means that the difference between the two is 1% or less when the size of the nozzle forming region S3 of one head chip 3 is 100%.

[0051] As described above, the multiple head chips 3 are arranged in a staggered manner along the Y1 direction, and five or more head chips are provided. In the illustrated example, seven head chips 3 are provided. The multiple head chips 3 are arranged such that a part of the nozzle forming region S3 of one head chip 3 of adjacent head chips 3 overlaps a part of the nozzle forming region S3 of the other head chip 3 when viewed in the X1 direction, forming an overlapping region A. Therefore, the overlapping region A exists between the adjacent head chips 3. Thus, the multiple head chips 3 include multiple overlapping regions A. The Y1 direction and the X1 direction are parallel to the nozzle forming region S3 and perpendicular to the Z1 direction, which is the ink ejection direction.

[0052] The multiple overlapping regions A include a first overlapping region A1, a second overlapping region A2, a third overlapping region A3, a fourth overlapping region A4, a fifth overlapping region A5, and a sixth overlapping region A6.

[0053] The first overlap region A1 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-4 and a part of the nozzle forming region S3 of the head chip 3-5 overlap when viewed in the X1 direction. The first overlap region A1 is closest to the center position O1 among the multiple overlap regions A. The center position O1 is the center position in the Y1 direction of all the nozzle forming regions S30.

[0054] The second overlap region A2 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-6 and a part of the nozzle forming region S3 of the head chip 3-7 overlap when viewed in the X1 direction. The second overlap region A2 is farther away from the center position O1 than the first overlap region A1. In this embodiment, the second overlap region A2 is provided in the Y2 direction with respect to the first overlap region A1. Furthermore, the second overlap region A2 is located furthest in the Y2 direction among the multiple overlap regions A with respect to the Y1 direction. Furthermore, the size of the second overlap region A2, i.e., the length along the Y axis, is greater than the size of the first overlap region A1, i.e., the length along the Y axis.

[0055] The third overlap region A3 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-1 and a part of the nozzle forming region S3 of the head chip 3-2 overlap when viewed in the X1 direction. The third overlap region A3 is farther from the center position O1 than the first overlap region A1. In this embodiment, the third overlap region A3 is provided in the Y1 direction with respect to the first overlap region A1. The third overlap region A3 is located furthest in the Y1 direction among the multiple overlap regions A. The size of the third overlap region A3, that is, the length in the direction along the Y axis, is larger than the size of the first overlap region A1. The size of the third overlap region A3 is approximately the same as the size of the second overlap region A2. Note that approximately the same means that the difference between the two is 1% or less when the size of the nozzle forming region S3 of one head chip 3 is 100%.

[0056] The fourth overlap region A4 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-4 and a part of the nozzle forming region S3 of the head chip 3-3 overlap when viewed in the X1 direction. The fourth overlap region A4 is disposed with the center position O1 between it and the first overlap region A1. In this embodiment, the distance between the fourth overlap region A4 and the center position O1 is approximately the same as the distance between the first overlap region A1 and the center position O1. Therefore, the fourth overlap region A4 is the overlap region A closest to the center position O1 among the multiple overlap regions A, similar to the first overlap region A1. Also, the size of the fourth overlap region A4, that is, the length in the direction along the Y axis, is approximately the same as the size of the first overlap region A1.

[0057] The fifth overlap region A5 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-5 and a part of the nozzle forming region S3 of the head chip 3-6 overlap when viewed in the X1 direction. The fifth overlap region A5 is farther away from the center position O1 than the first overlap region A1. In this embodiment, the fifth overlap region A5 is provided in the Y2 direction with respect to the first overlap region A1. The fifth overlap region A5 is disposed between the first overlap region A1 and the second overlap region A2 with respect to the Y1 direction. The size of the fifth overlap region A5, i.e., the length in the direction along the Y axis, is approximately the same as the size of the first overlap region A1.

[0058] The sixth overlap region A6 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-2 and a part of the nozzle forming region S3 of the head chip 3-3 overlap when viewed in the X1 direction. The sixth overlap region A6 is farther away from the center position O1 than the fourth overlap region A4. In this embodiment, the sixth overlap region A6 is provided in the Y1 direction with respect to the fourth overlap region A4. The sixth overlap region A6 is disposed between the fourth overlap region A4 and the third overlap region A3 with respect to the Y1 direction. Also, the size of the sixth overlap region A6, i.e., the length in the direction along the Y axis, is approximately the same as the size of the fourth overlap region A4.

[0059] The fourth overlap region A4, the third overlap region A3, and the sixth overlap region A6 may be regarded as the first overlap region A1, the second overlap region A2, and the fifth overlap region A5. The number of head chips 3 may be five or more, and may be six, eight, or more.

[0060] In addition, in each overlap region A, several nozzles N belonging to the nozzle forming region S3 of one of two adjacent head chips 3 overlap with several nozzles N belonging to the nozzle forming region S3 of the other head chip 3 for each nozzle row L when viewed in the X1 direction.

[0061] Furthermore, each head chip 3 includes, among its nozzle forming region S3, a non-overlapping region B that does not overlap, when viewed in the X1 direction, with the nozzle forming region S3 of an adjacent head chip 3. The non-overlapping region B is a region different from the overlapping region A. The non-overlapping region B includes multiple non-overlapping regions B1, B2, B3, B4, B5, B6, and B7.

[0062] The non-overlapping region B1 is a region of the nozzle forming region S3 of the head chip 3-4 that is different from the first overlapping region A1 and the fourth overlapping region A4. The non-overlapping region B1 is a remaining region of the nozzle forming region S3 of the head chip 3-4 excluding the first overlapping region A1 and the fourth overlapping region A4. In this embodiment, the size of the non-overlapping region B1, that is, the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-4. The size of the non-overlapping region B1 is larger than the size of each of the first overlapping region A1 and the fourth overlapping region A4.

[0063] The non-overlapping region B2 is a region of the nozzle forming region S3 of the head chip 3-5 that is different from the first overlapping region A1 and the fifth overlapping region A5. The non-overlapping region B2 is a remaining region of the nozzle forming region S3 of the head chip 3-5 excluding the first overlapping region A1 and the fifth overlapping region A5. In this embodiment, the size of the non-overlapping region B2, that is, the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-5. The size of the non-overlapping region B2 is larger than the size of each of the first overlapping region A1 and the fifth overlapping region A5.

[0064] The non-overlapping region B3 is a region of the nozzle forming region S3 of the head chip 3-6 that is different from the second overlapping region A2 and the fifth overlapping region A5. The non-overlapping region B3 is a remaining region of the nozzle forming region S3 of the head chip 3-6 excluding the second overlapping region A2 and the fifth overlapping region A5. In this embodiment, the size of the non-overlapping region B3, that is, the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-6. The size of the non-overlapping region B3 is larger than the size of each of the second overlapping region A2 and the fifth overlapping region A5.

[0065] The non-overlapping region B4 is a region of the nozzle forming region S3 of the head chip 3-7 that is different from the second overlapping region A2. The non-overlapping region B4 is the remaining region of the nozzle forming region S3 of the head chip 3-7 excluding the second overlapping region A2. In this embodiment, the size of the non-overlapping region B4, i.e., the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-7. The size of the non-overlapping region B4 is larger than the size of the second overlapping region A2.

[0066] The non-overlapping region B5 is a region of the nozzle forming region S3 of the head chip 3-3 that is different from the fourth overlapping region A4 and the sixth overlapping region A6. The non-overlapping region B5 is a remaining region of the nozzle forming region S3 of the head chip 3-3 excluding the fourth overlapping region A4 and the sixth overlapping region A6. In this embodiment, the size of the non-overlapping region B5, i.e., the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-3. The size of the non-overlapping region B5 is larger than the size of each of the fourth overlapping region A4 and the sixth overlapping region A6.

[0067] The non-overlapping region B6 is a region of the nozzle forming region S3 of the head chip 3-2 that is different from the third overlapping region A3 and the sixth overlapping region A6. The non-overlapping region B6 is a remaining region of the nozzle forming region S3 of the head chip 3-2 excluding the third overlapping region A3 and the sixth overlapping region A6. In this embodiment, the size of the non-overlapping region B6, that is, the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-2. The size of the non-overlapping region B6 is larger than the size of each of the third overlapping region A3 and the sixth overlapping region A6.

[0068] The non-overlapping region B7 is a region of the nozzle forming region S3 of the head chip 3-1 that is different from the third overlapping region A3. The non-overlapping region B7 is the remaining region of the nozzle forming region S3 of the head chip 3-1 excluding the third overlapping region A3. In this embodiment, the size of the non-overlapping region B7, i.e., the length in the direction along the Y axis, is more than half the size of the nozzle forming region S3 of the head chip 3-1. The size of the non-overlapping region B7 is larger than the size of the third overlapping region A3.

[0069] As described above, the second overlap region A2 is larger than the first overlap region A1 in the Y1 direction. By satisfying this relationship, the temperature difference in the entire nozzle forming region S30 can be reduced compared to a case where this relationship is not satisfied. Therefore, the influence of warping of the members constituting the liquid jet head 30 can be mitigated.

[0070] As described above, each of the plurality of head chips 3 has a wiring board 40 including a driving IC 41 connected to a driving element 34 for ejecting liquid. The driving IC 41 of the wiring board 40 is a heat source of the head chip 3.

[0071] The larger the size of the overlap region A, that is, the length along the Y axis, the more likely it is that the heat will be high in the overlap region A. In other words, the larger the overlap amount of the overlap region A, the more likely it is that the overlap region A will become hot. For example, head chip 3-4, which is close to central position O1, is adjacent to the other four head chips 3-2, 3-3, 3-5, and 3-6. Meanwhile, head chips 3-1 and 3-7, which are closest to both ends of total nozzle forming region S30 in the Y1 direction, are each adjacent to only two other head chips 3. The closer to central position O1 of total nozzle forming region S30, the more difficult it is for heat from head chip 3 to be dissipated, and the closer to both ends, the more easily heat from head chip 3 can be dissipated.

[0072] Furthermore, the head chip 3 closer to the central position O1 generally requires a greater number of ink ejections from the nozzles N for image formation than the head chip 3 farther from the central position O1. That is, the driving IC 41 of the head chip 3 closer to the central position O1 is more likely to generate heat than the driving IC 41 of the head chip 3 farther from the central position O1.

[0073] Therefore, by making the second overlapping region A2 arranged on the head chip 3 side where heat is easily dissipated a larger amount of overlapping, which is more likely to become hot, compared to the first overlapping region A1, it is possible to uniformize the temperature in all nozzle forming regions S30. Therefore, it is possible to reduce the risk of warping of the members that are long in the direction along the Y axis constituting the liquid ejection head 30, such as the frame portion 531 and the fixed plate 532. Therefore, it is possible to suppress the deterioration of print quality caused by warping of the members of the liquid ejection head 30. Incidentally, when trying to make the fixed plate 532 thin in order to shorten the distance between the medium M and the ejection surface FN and improve the print quality, it is preferable to form the fixed plate 532 from metal to ensure rigidity, and it is also preferable to form the frame portion 531 having a complex shape from resin so that it can be inexpensively formed by injection molding. In other words, when the fixing plate 532 is made of metal and the frame portion 531 is made of resin, the difference in the linear expansion coefficient between the two is large, making it easier for one to warp relative to the other. However, as in this embodiment, the second overlapping region A2, which is located on the head chip 3 side where heat is more easily dissipated, is made an area with a large amount of overlap that is more likely to become hot than the first overlapping region A1, thereby effectively mitigating this warping.

[0074] Fig. 8 is a bottom view of a liquid jet head 30x of a comparative example. As shown in Fig. 8, in the conventional liquid jet head 30x, the sizes of the multiple overlapping regions A are substantially the same. In such a liquid jet head 30x, the temperature near the center position O1 of all the nozzle forming regions S30 is more likely to rise than the temperatures at both ends. This may cause warping of the fixed plate 532, for example, which may result in a deterioration in print quality.

[0075] 7, in the present embodiment, the second overlap region A2 is the overlap region A that is disposed at the end of the multiple overlap regions A in the Y1 direction. In this case, since the second overlap region A2 is larger than the first overlap region A1, the effect of reducing the temperature difference in the entire nozzle forming region S30 is significantly exhibited.

[0076] The first overlap region A1 is the overlap region A that is closest to the center position O1 in the Y1 direction among the multiple overlap regions A. In this case, since the second overlap region A2 is larger than the first overlap region A1, the effect of reducing the temperature difference in the entire nozzle forming region S30 is significantly exhibited.

[0077] In particular, in this embodiment, the second overlap region A2 is the overlap region A that is arranged at the end of the multiple overlap regions A in the Y1 direction, and the first overlap region A1 is the overlap region A that is closest to the center position O1 in the Y1 direction among the multiple overlap regions A. By arranging the first overlap region A1 and the second overlap region A2 in the above manner, the effect of reducing the temperature difference in the entire nozzle forming region S30 is particularly remarkable.

[0078] Furthermore, with respect to the Y1 direction, the size of the second overlap region A2, i.e., the length along the Y axis, is preferably at least twice the average size of the multiple overlap regions A, i.e., the length along the Y axis. If the size of the second overlap region A2 is less than twice the average size of the multiple overlap regions A, the effect of reducing the temperature difference within all of the nozzle forming regions S30 is weakened compared to when the size is at least twice the average size.

[0079] From another perspective, it is preferable that the number of nozzles belonging to the second overlap region A2 is more than twice the average number of nozzles belonging to the multiple overlap regions A. For example, consider a case where the number of nozzles in each of the first overlap region A1, the fourth overlap region A4, the fifth overlap region A5, and the sixth overlap region A6 is 9, and the number of nozzles in each of the second overlap region A2 and the third overlap region A3 is 64. In this case, the average number of nozzles belonging to the multiple overlap regions A is about 27. Therefore, twice the average is about 54. By having the number of nozzles belonging to the second overlap region A2 be more than twice the average number of nozzles, the second overlap region A2 arranged on the head chip 3 side, which is more likely to dissipate heat, can be made into a region with a large amount of overlap that is more likely to become hot, compared to a case where the number of nozzles is less than twice the average number of nozzles. This makes it easier to reduce the temperature difference in the entire nozzle formation region S30.

[0080] The size of the second overlap region A2 may be less than twice the average size of the multiple overlap regions A. Furthermore, the number of nozzles belonging to the second overlap region A2 may be less than twice the average number of nozzles belonging to the multiple overlap regions A.

[0081] In the Y1 direction, the size of the first overlap region A1 is preferably 1 / 2 or less the average size of the multiple overlap regions A. By making the size of the first overlap region A1 1 / 2 or less the average size of the multiple overlap regions A, it is easier to achieve a longer line head than if the size exceeds 1 / 2.

[0082] From another perspective, it is preferable that the number of nozzles belonging to the first overlap region A1 is 1 / 2 or more times the average number of nozzles belonging to the multiple overlap regions A. For example, consider a case where the number of nozzles in each of the first overlap region A1, the fourth overlap region A4, the fifth overlap region A5, and the sixth overlap region A6 is 9, and the number of nozzles in each of the second overlap region A2 and the third overlap region A3 is 64. In this case, the average number of nozzles belonging to the multiple overlap regions A is about 27. Therefore, 1 / 2 times the average is about 14. By having the number of nozzles belonging to the first overlap region A1 be 1 / 2 or less of the average number of nozzles belonging to the multiple overlap regions A, it is easier to achieve a long line head compared to a case where the number exceeds 1 / 2.

[0083] In particular, it is preferable that the size of the second overlap region A2 in the Y1 direction is at least twice the average size of the multiple overlap regions A, and that the size of the first overlap region A1 in the Y1 direction is at most 1 / 2 the average size of the multiple overlap regions A. By satisfying these relationships, the effect of the second overlap region A2 being larger than the first overlap region A1 is less likely to be achieved than when these relationships are not satisfied. Therefore, it is possible to uniformize the temperature in all nozzle formation regions S30, and it is possible to suppress the occurrence of warping of the members of the liquid jet head 30. In addition, the liquid jet head 30 can be suitably used as a line head.

[0084] The size of the first overlap region A1 may exceed 1 / 2 the average size of the multiple overlap regions A. Furthermore, the number of nozzles belonging to the first overlap region A1 may exceed 1 / 2 the average number of nozzles belonging to the multiple overlap regions A.

[0085] In the Y1 direction, the size of the second overlap region A2 is preferably 5 times or more the size of the first overlap region A1. When the size of the second overlap region A2 is 5 times or more the size of the first overlap region A1, the temperature difference between the vicinity of the center position O1 and the vicinity of the end of all the nozzle forming regions S30 can be suitably reduced compared to when the size is less than 5 times. Therefore, it is possible to suppress the occurrence of warping of the members of the liquid ejection head 30 due to a part of the all the nozzle forming regions S30 becoming hot. The size of the second overlap region A2 may be 7 times or more the size of the first overlap region A1. The size of the second overlap region A2 may be less than 5 times the size of the first overlap region A1.

[0086] The overlapping regions A include a third overlapping region A3 in addition to the second overlapping region A2. The size of the second overlapping region A2 in the Y1 direction is approximately the same as the size of the third overlapping region A3. By providing the third overlapping region A3, the amount of heat generated at both ends of all the nozzle forming regions S30 can be uniformly distributed.

[0087] Note that "substantially the same size" refers to a difference between the two being 1% or less when the size of the nozzle formation region of one head chip 3 in the first direction is 100%. For example, when the number of nozzles included in the nozzle formation region S3 of one head chip 3 in the first direction is 400 nozzles, "substantially the same size" refers to 1% of that, or 4 nozzles or less.

[0088] The overlapping regions A further include a fourth overlapping region A4. In the Y1 direction, the size of the fourth overlapping region A4 is substantially the same as that of the first overlapping region A1. By providing the fourth overlapping region A4, the temperature distribution around the center position O1 is made uniform. This reduces the heat bias around the center position O1 in the entire nozzle forming region S30.

[0089] In the Y1 direction, the total size of the multiple overlapping regions A is smaller than the size of the nozzle forming region S3 of one head chip 3. Since the total size is smaller than the size of the nozzle forming region S3, it is possible to avoid excessively increasing the number of nozzles included in the overlapping region A compared to the case where the total size is larger, and the liquid ejecting head 30 can be suitably used as a line head. Note that the total size may be larger than the size of one nozzle forming region S3.

[0090] Fig. 9 is a diagram showing the overlapping number of nozzles that eject ink droplets in the first overlapping region A1. Fig. 10 is a diagram showing the overlapping number of nozzles that eject ink droplets in the second overlapping region A2. Note that Figs. 9 and 10 show the nozzle row La of each head chip 3 as a representative.

[0091] The number of nozzles in the first overlap region A1 is different from that in the second overlap region A2, but the overlapping number of nozzles used to eject ink droplets may be set to be equal.

[0092] 9, seven nozzles in the nozzle row La of the head chip 3-4 belong to the first overlapping region A1, and seven nozzles in the nozzle row La of the head chip 3-5 belong to the first overlapping region A1. Of the seven nozzles N, three nozzles N9 and two nozzles N8 are nozzles N used to eject ink droplets. In the second overlapping region A2, the three nozzles N9 of the head chip 3-6 and the three nozzles N9 of the head chip 3-5 overlap in the X1 direction.

[0093] Therefore, the number of nozzles belonging to the first overlap region A1 is 7 in one nozzle row La. In contrast, in the first overlap region A1, the number of overlapping nozzles used to eject ink droplets in one nozzle row La is 3.

[0094] 10, 17 nozzles in the nozzle row La of the head chip 3-6 belong to the second overlap region A2, and 17 nozzles in the nozzle row La of the head chip 3-7 belong to the second overlap region A2. Of the 17 nozzles N, three nozzles N9 and seven nozzles N8 are nozzles N used to eject ink droplets. In the second overlap region A2, the three nozzles N9 of the head chip 3-5 and the three nozzles N9 of the head chip 3-4 overlap in the X1 direction.

[0095] Therefore, the number of nozzles belonging to the second overlap region A2 in one nozzle row La is 17. In contrast, in the second overlap region A2, the number of overlapping nozzles used to eject ink droplets in one nozzle row La is three.

[0096] The first overlap region A1 and the second overlap region A2 have the same overlapping number of nozzles used to eject ink droplets. By making the overlapping number equal in each overlap region A, it is possible to reduce the difference in the overlapping degree of ink droplets that land between the head chips 3, even if the second overlap region A2 is larger than the first overlap region A1 in the Y1 direction.

[0097] 2. Variations Each of the above-mentioned exemplary embodiments may be modified in various ways. Specific modified embodiments that may be applied to each of the above-mentioned embodiments are illustrated below. Two or more embodiments selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[0098] 2-1. First modified example FIG. 11 is a bottom view of the liquid jet head 30A of the first modified example. In the liquid jet head 30A of the first modified example shown in FIG. 11, the size of the fifth overlap region A5 is larger than that of the first overlap region A1 and smaller than that of the second overlap region A2 in the Y1 direction. That is, the sizes of the first overlap region A1, the fifth overlap region A5, and the second overlap region A2 are larger in this order. Therefore, the size of the overlap region A increases stepwise toward the end of the entire nozzle forming region S30 in the Y1 direction. According to this modified example, compared to the above-mentioned embodiment, the part of the head chip 3 that belongs to the overlap region A, which is likely to become hot, is dispersed stepwise. Therefore, the heat bias in the entire nozzle forming region S30 can be further reduced. Note that, similarly, with respect to the third overlap region A3, the fourth overlap region A4, and the sixth overlap region A6, the sixth overlap region A6 is smaller than the third overlap region A3 and larger than the fourth overlap region A4 in the Y1 direction.

[0099] 2-2. Second modified example FIG. 12 is a bottom view of a liquid jet head 30B of a second modified example. The liquid jet head 30B of the second modified example shown in FIG. 12 has six head chips 3. The number of head chips 3 included in the liquid jet head 30B is an even number. In the example of FIG. 12, the head chip 3-1 is omitted. In the example of FIG. 12, the third overlap region A3 is an overlap region A where a part of the nozzle forming region S3 of the head chip 3-2 and a part of the nozzle forming region S3 of the head chip 3-3 overlap when viewed in the X1 direction. In addition, the center position O1 is located within the first overlap region A1 in the Y1 direction. This modified example can also reduce the heat bias in all the nozzle forming regions S30.

[0100] 2-3.Other Modifications Although head chip 3 does not have a structure for circulating ink, head chip 3 may be a circulation type head having a so-called circulation flow path.

[0101] A "liquid ejection apparatus" may be employed in various devices such as facsimile machines and copy machines, in addition to devices dedicated to printing. The uses of a liquid ejection apparatus are not limited to printing. For example, a liquid ejection apparatus that ejects a solution of a coloring material is used as a manufacturing apparatus for forming color filters for display devices such as liquid crystal display panels. A liquid ejection apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes for a wiring board. A liquid ejection apparatus that ejects a solution of an organic substance related to a living organism is used as a manufacturing apparatus for manufacturing biochips, for example.

[0102] Although the present invention has been described based on the preferred embodiment, the present invention is not limited to the above-mentioned embodiment. Furthermore, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above-mentioned embodiment, and any configuration can be added. [Explanation of symbols]

[0103] 3...head chip, 30...liquid ejection head, 34...driving element, 37...nozzle plate, 40...wiring board, 41...driving IC, 60...part, 100...liquid ejection device, 312...throttling section, 314...communicating flow path, 320...wall surface, A...overlapping area, A1...first overlapping area, A2...second overlapping area, A3...third overlapping area, A4...fourth overlapping area, A5...fifth overlapping area, A6...sixth overlapping area, B...non-overlapping area, L...nozzle row, M...medium, N...nozzle, O1...center position, S3...nozzle forming area, S30...total nozzle forming area.

Claims

1. A plurality of head chips, five or more of which are arranged in a staggered pattern along a first direction; A support member for supporting the plurality of head chips; Equipped with the plurality of head chips are arranged such that adjacent head chips have an overlapping region in which a part of a nozzle forming region of one head chip overlaps a part of a nozzle forming region of the other head chip when viewed in a second direction perpendicular to the first direction, the plurality of overlapping regions include a first overlapping region and a second overlapping region that is farther in the first direction than the first overlapping region from a center position in the first direction of all nozzle forming regions that are constituted by all nozzle forming regions of the plurality of head chips, In the first direction, the second overlapping region is larger than the first overlapping region. A liquid jet head comprising:

2. The second overlap region is an overlap region that is disposed at the end of the plurality of overlap regions in the first direction. The liquid jet head according to claim 1 .

3. The first overlapping region is an overlapping region that is closest to the center position among the plurality of overlapping regions in the first direction. The liquid jet head according to claim 1 .

4. the first overlapping region is an overlapping region that is closest to the center position among the plurality of overlapping regions in the first direction; The second overlap region is an overlap region that is disposed at the end of the plurality of overlap regions in the first direction. The liquid jet head according to claim 1 .

5. In the first direction, a size of the second overlap region is equal to or greater than twice an average size of the plurality of overlap regions. The liquid jet head according to claim 1 .

6. With respect to the first direction, a size of the first overlapping region is equal to or smaller than ½ of an average size of the plurality of overlapping regions. The liquid jet head according to claim 1 .

7. In the first direction, a size of the second overlap region is equal to or greater than twice an average size of the plurality of overlap regions; With respect to the first direction, a size of the first overlapping region is equal to or smaller than ½ of an average size of the plurality of overlapping regions. The liquid jet head according to claim 1 .

8. With respect to the first direction, a size of the second overlapping region is five times or more a size of the first overlapping region. The liquid jet head according to claim 1 .

9. Each of the plurality of head chips has a driving IC connected to a driving element for ejecting liquid. The liquid jet head according to claim 1 .

10. the plurality of overlapping regions includes a third overlapping region different from the second overlapping region, the third overlap region is an overlap region that is disposed at the end of the plurality of overlap regions in the first direction, With respect to the first direction, a size of the second overlapping region is substantially the same as a size of the third overlapping region. The liquid jet head according to claim 2 .

11. the plurality of overlapping regions includes a fourth overlapping region different from the first overlapping region, the fourth overlap region is an overlap region other than the overlap regions disposed at both ends of the plurality of overlap regions in the first direction, With respect to the first direction, a size of the fourth overlapping region is substantially the same as a size of the first overlapping region. The liquid jet head according to claim 3 .

12. the plurality of overlapping regions include a fifth overlapping region disposed between the first overlapping region and the second overlapping region in the first direction, A size of the fifth overlapping region in the first direction is larger than a size of the first overlapping region and smaller than a size of the second overlapping region. The liquid jet head according to claim 1 .

13. a total size of the plurality of overlapping regions in the first direction is smaller than a size of the nozzle forming region of the head chip; The liquid jet head according to claim 1 .

14. The liquid jet head according to claim 1 , which jets liquid onto a medium; A conveying unit that conveys the medium; A liquid ejection apparatus comprising:

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