Liquid discharge head and liquid discharge device

Abstract

To provide a liquid discharge head which improves electric reliability of wiring in a bent part of a flexible wiring board.SOLUTION: A liquid discharge head has an element substrate having an element driven by a driving signal and a discharge port for discharging liquid by driving of the element, a flexible wiring board having wiring for supplying the driving signal to the element, and a support member for supporting the element substrate and the flexible wiring board on a first surface, where the flexible wiring board has a bent part bent along one side extending in a first direction, of the support member, and the bent part has no wiring in a region facing the side of the element substrate in a second direction perpendicular to the first direction, when being viewed from a direction vertical to the first surface.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] A liquid ejection head used in a liquid ejection device such as an inkjet recording device drives energy generating elements based on electrical signals from the device body, causing droplets to be ejected from tiny ejection orifices. The liquid ejection head is mounted on the recording device body and is controlled and driven by electrical signals supplied from the recording device body to eject liquid onto a medium to form an image. Therefore, the liquid ejection head has an electrical wiring board for transmitting drive signals and the like. Generally, a liquid ejection head has an element substrate equipped with energy generating elements and ejection orifices, and a flexible wiring board as an electrical wiring board electrically connected to the element substrate.

[0003] The electrical wiring board has an electrical signal input section including conductive contact pads, and the recording device body has contact pins that electrically connect to the contact pads. Electrical communication is possible when the contact pads come into contact with the contact pins.

[0004] In recent years, liquid ejection devices and liquid ejection heads have been required to produce high-resolution images quickly and inexpensively. To this end, energy-generating elements are becoming more highly integrated on element substrates, and the number of wires within flexible electrical wiring boards (flexible boards) is correspondingly increasing. One way to accommodate the increased number of wires is to make the flexible wiring board itself wider and longer. In this case, the larger flexible wiring board can be folded and fixed along the housing of the liquid ejection head, thereby avoiding an increase in the size of the liquid ejection head.

[0005] Patent Document 1 discloses a configuration in which a flexible wiring board electrically connected to an element substrate is bent and fixed to the surface of a housing of a liquid ejection head. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-93452 A Summary of the Invention [Problem to be solved by the invention]

[0007] When bending a flexible wiring board, it is preferable to bend it at a curvature close to a right angle in order to prevent an increase in the paper holding width, which reduces the amount of cockling of the ejection medium, such as paper, in the area where the liquid is ejected. This is because an increase in the paper holding width leads to an increase in the size of the device body and therefore to increased costs. On the other hand, if the bending rate is small, the wiring inside the flexible wiring board may be damaged, such as by cracking, at the bent part.

[0008] SUMMARY OF THE INVENTION The present invention aims to solve the above problems and has an object to provide a liquid ejection head with improved electrical reliability of wiring at bent portions of a flexible wiring board. [Means for solving the problem]

[0009] One aspect of the present invention that solves the above problem is a liquid ejection head having an element substrate having elements driven by a drive signal and ejection ports that eject liquid by driving the elements, a flexible wiring board with wiring for supplying the drive signal to the elements, and a support member that supports the element substrate and the flexible wiring board on a first surface, wherein the flexible wiring board has a bent portion that is bent along a side of the support member that extends in a first direction, and when viewed from a direction perpendicular to the first surface, the bent portion does not have the wiring in an area that faces the side of the element substrate in a second direction that is perpendicular to the first direction.

[0010] Another aspect of the present invention is a liquid ejection head having an element substrate having elements driven by a drive signal, ejection ports that eject liquid by driving the elements, and terminals for receiving the drive signal from outside, a flexible wiring board having wiring for supplying the drive signal to the elements, and a support member that supports the element substrate and the flexible wiring board on a first surface, wherein the flexible wiring board has a bent portion bent along one end of the support member that extends in a first direction, and when viewed from a direction perpendicular to the first surface, the bent portion has an opening that includes an area that faces a side of the element substrate in a second direction that is perpendicular to the first direction. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain a liquid ejection head in which the electrical reliability of the wiring at the bent portion of the flexible wiring board is improved. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are a schematic configuration diagram and a control block diagram illustrating an example of a liquid ejection device. [Figure 2] FIG. 1 is an exploded perspective view showing an example of a liquid ejection head. [Figure 3] FIG. 1 is a schematic perspective view showing an example of a liquid ejection head. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of a discharge unit. [Figure 5] FIG. 10 is a schematic diagram illustrating a discharge unit of a comparative example. [Figure 6] FIG. 10 is a cross-sectional view showing a discharge unit of a comparative example. [Figure 7] FIG. 10 is a cross-sectional view showing a discharge unit of a comparative example. [Figure 8] FIG. 2 is a schematic view showing a discharge unit according to the first embodiment. [Figure 9] FIG. 2 is a schematic view showing a discharge unit according to the first embodiment. [Figure 10] FIG. 2 is a cross-sectional view showing a discharge unit according to the first embodiment. [Figure 11] FIG. 10 is a schematic view showing a discharge unit according to a second embodiment. [Figure 12] FIG. 10 is a cross-sectional view showing a discharge unit according to a second embodiment. [Figure 13] FIG. 10 is a schematic view showing a discharge unit according to a third embodiment. [Figure 14] FIG. 10 is a schematic view showing a discharge unit according to a fourth embodiment. [Figure 15] 10A and 10B are a schematic view and a cross-sectional view showing a discharge unit according to a fifth embodiment. [Figure 16] FIG. 10 is a schematic diagram illustrating a discharge unit of a comparative example. [Figure 17] FIG. 10 is a schematic view showing a discharge unit according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will now be described with reference to the accompanying drawings. However, the following description is not intended to limit the scope of the present invention. As an example, the present embodiment employs a thermal system in which a heat-generating element generates bubbles to eject liquid. However, the present invention can also be applied to liquid ejection heads employing a piezo system that uses a piezoelectric element as the energy-generating element for ejecting liquid, or various other liquid ejection systems. The liquid ejection head and liquid ejection device incorporating the liquid ejection head of the present invention can be used in devices such as inkjet printers, copiers, facsimiles with communication systems, and word processors with printer units. Furthermore, the liquid ejection head and liquid ejection device can be used in industrial recording devices combined with various processing devices. For example, the liquid ejection head can also be used in applications such as biochip fabrication, electronic circuit printing, and semiconductor substrate fabrication.

[0014] Although the present embodiment is directed to a liquid ejection device in which a liquid such as ink is circulated between a tank and a liquid ejection head, other configurations are also possible. For example, the liquid may be circulated between a tank and a liquid ejection head. Alternatively, instead of circulating the liquid, two tanks may be provided upstream and downstream of the liquid ejection head, and the liquid may flow from one tank to the other, thereby causing the liquid to flow within the pressure chamber.

[0015] (First embodiment) FIG. 1(a) is a schematic perspective view of an example of the configuration of a liquid ejection device 50 using a liquid ejection head 1 to which the present invention can be applied, and FIG. 1(b) is a block diagram of the control system of the liquid ejection device 50. The liquid ejection device 50 shown in FIG. 1(a) is a serial scan inkjet printer in which the liquid ejection head 1 performs a scanning motion to eject ink and record an image or the like on a medium P. The liquid ejection head 1 is mounted on a carriage 53, which moves along a guide shaft 51 in the main scanning direction indicated by arrow X. The medium P is transported by transport rollers 55, 56, 57, and 58 in the sub-scanning direction indicated by arrow Y, which intersects (orthogonal in this example) the main scanning direction. In the figure, the X direction is the scanning direction of the carriage 53 and corresponds to the width direction of the medium P, the Y direction is the transport direction of the medium P, and the Z direction is the direction intersecting the X and Y directions and opposite to the direction in which liquid is ejected. The liquid ejection head 1 is equipped with a circulation unit 54, which circulates ink in a discharge unit 300 (described later). The ejection elements (described later) provided in the ejection unit 300 are driven by the head driver 1A in response to input signals from an electrical connection board. Electrical wiring required for ejection, and piping for ink and air are supplied to the carriage 53 by a guide 59.

[0016] A CPU (control unit) 400 controls the liquid ejection device 50 based on programs such as processing procedures stored in a ROM 401, and a RAM 402 is used as a work area for executing these processes. The CPU 400 controls a head driver 1A based on image data from a host device 500 external to the liquid ejection device 50. The CPU 400 also controls a carriage motor 403 for moving the carriage 53 via a motor driver 403A, and a transport motor 404 for transporting the medium P via a motor driver 404A.

[0017] As shown in FIG. 1(a), the liquid ejection head 1 is configured to be capable of full-color printing using CMYK inks (cyan, magenta, yellow, and black). The liquid ejected by the liquid ejection head 1 is not limited to this, and the head may be configured to eject a reaction liquid or the like as white ink, or to eject only black ink. A cap member (not shown) is positioned away from the transport path of the medium P, and when liquid ejection is not being performed, it moves relatively to a position that covers the face of the liquid ejection head 1, preventing the ejection ports from drying out and performing a suction operation for filling and recovery.

[0018] FIG. 2 is an exploded perspective view showing the liquid ejection head 1 of this embodiment. As shown in FIG. 2 and FIG. 1(a), the liquid ejection head 1 has a circulation unit 54. The circulation unit 54 has circulation units corresponding to the types of liquids (ink, reaction liquid, etc.) to be ejected. In this embodiment, circulation units 54m, 54y, 54k, and 54c are provided corresponding to magenta ink, yellow ink, black ink, and cyan ink, respectively. Each circulation unit 54 is connected to a flow path member 110, which is the housing of the liquid ejection head 1. The circulation unit 54 and the flow path member 110 can be connected by any connection method, such as screw fastening with a sealing member sandwiched between them or welding. The flow path member 110 has a connection member 200 having a supply port for receiving ink from the device main body, and the connection member 200 is connected to each circulation unit 54 (54m, 54y, 54k, and 54c).

[0019] When the liquid ejection head 1 is attached to the apparatus body, a supply tube (not shown) corresponding to the type of liquid (ink) to be ejected is connected to the ink supply port 201 of the connection member 200. The supply tube is provided in the guide 59 shown in FIG. 1(a). Each ink supplied from the supply tube passes through the connection member 200 of the flow path member 110 and is supplied to each circulation unit 54. A discharge unit 300 is connected to the bottom surface (surface in the -Z direction) of the flow path member 110, and the ink supplied to the circulation unit 54 is supplied to the discharge unit 300 via the flow path member 110.

[0020] The ejection unit 300 and the flow path member 110 can be connected by any method, including bonding using an adhesive or fastening with screws sandwiching a sealing member. The ejection unit 300 includes an element substrate 310 equipped with ejection ports for ejecting ink and ejection elements for ejecting ink, a flexible wiring board 330 for transmitting electrical signals to the element substrate 310, a support member 320 supporting the element substrate 310 and the flexible wiring board 330, and a cover member 340 covering the flexible wiring board 330. The element substrate 310 and the flexible wiring board 330 are adhesively fixed to a first surface 322 of the support member 320. Furthermore, a cover member 340 is adhesively bonded to cover the surface of the element substrate 310 that is the side equipped with the ejection ports. The cover member 340 has an opening at a location corresponding to the element substrate 310. The support member 320 also serves as a flow path member having a flow path 321 for supplying ink from the circulation unit 54 to the element substrate 310.

[0021] Fig. 3(a) is a schematic perspective view of the liquid ejection head 1 of this embodiment as seen from the electric wiring board 210 side, and Fig. 3(b) is a schematic perspective view of the liquid ejection head 1 as seen from the connecting member 200 side. As shown in Fig. 3, the flexible wiring board 330 is bonded to the surface of the support member 320 that supports the element substrate 310. The flexible wiring board 330 is disposed in the flow path member 110 serving as a housing so as to have a bent portion 502A on the electric wiring board 210 side of the support member 320 and a bent portion 502B on the connecting member 200 side. In this specification, the "bent portion" of the flexible wiring board refers to a portion where the flexible wiring board is bent and has a curved shape.

[0022] When the flexible wiring board 330 is bonded, it is also disposed on both surfaces of the support member 320 to which the ejection elements 310 are not bonded. When disposing, as shown in FIG. 2, the flexible wiring board 330 may be bent to fit along the sides of the support member 320 and then bonded to the support member 320. Alternatively, a portion of the flexible wiring board 330 may be bonded to the support member 320, and then the flexible wiring board 330 may be bent to fit along the support member 320. Alternatively, the flexible wiring board 330 may be bent to fit along the support member 320 after the cover member 340 is bonded. Alternatively, the flexible wiring board 330 may not have a cover member 340. Alternatively, unlike the configuration shown in FIG. 2, the cover member 340 may be bonded to the support member 320, and the flexible wiring board 330 may be bonded and bent onto the cover member 340.

[0023] In the space 509 between the support member 320 and the flexible wiring board 330, an adhesive or sealant 519 made of a resin material is inserted to strengthen the bonding strength and prevent a decrease in reliability due to ink penetration (see Figure 7).

[0024] The surface of the flow path member 110 opposite to the surface on which the connection member 200 is provided serves as a contact surface to which an electric wiring board 210 is connected, which receives an electric signal from the main body. An electric signal is sent from the electric wiring board 210 to the element substrate 310 via a flexible wiring board 330. The electric wiring board 210 can be connected to the flow path member 110 by any method, such as crimping, fixing with an adhesive, or fixing with double-sided tape. In this embodiment, the electric connection between the electric wiring board 210 and the flexible wiring board 330 is formed by ACF (anisotropic conductive film) compression bonding, but wire bonding, flying lead bonding, or the like may also be used.

[0025] FIG. 4 is a schematic diagram of the discharge unit 300 as viewed from the discharge port side of the element substrate 310. Note that in FIG. 4, the cover member 340 is not illustrated in order to illustrate the individual wiring (conductors) 503 provided on the flexible wiring substrate 330. The element substrate 310 has a plurality of connection terminals 504 electrically connected to the discharge elements along the long sides of the discharge elements 310. The connection terminals 504 are electrically connected to the wiring 503. In FIG. 4 and the schematic diagrams of the discharge unit shown in subsequent figures, only a portion of the wiring 503 and the connection terminals 504 are illustrated. Note that although the connection terminals 504 are arranged on only one long side of the element substrate 310 in FIG. 4, they may be arranged on both long sides of the element substrate 310. A configuration in which a plurality of connection terminals 504 are arranged along the short sides of the element substrate 310 may also be used. In this embodiment, the element substrate 310 and the flexible wiring substrate 330 are electrically connected by wire bonding. More specifically, the connection terminals 504 of the element substrate 310 and the wiring 503 of the flexible wiring substrate 330 are electrically connected by wire bonding. The electrical connection method may be other methods such as flying lead bonding.

[0026] Wiring 503 is routed within flexible wiring board 330 so as to be connected to electrical wiring board 210. Flexible wiring board 330 is joined to the upper surface of support member 320 (XY plane in FIG. 4), and the portion protruding from the upper surface of support member 320 is bent along the side surface of support member 320.

[0027] The problem to be solved by the present invention will be explained using a comparative example shown in FIG. 5. FIG. 5 is a schematic diagram showing a discharge unit 300 of the comparative example, showing a state in which an element substrate 310 and a flexible wiring substrate 330 are bonded onto a support member 320, before the flexible wiring substrate 330 is bent. Similar to FIG. 4, the cover member 340 is omitted in FIG. 5, and the electrical connection portion between the connection terminals 504 and the wiring 503 is also shown in a simplified form. In the comparative example shown in FIG. 5, a plurality of connection terminals 504 are arranged along the short side of the discharge element 310. In this case, when the wiring 503 is drawn from the connection terminals 504 on the connection member 200 side to the electrical wiring substrate 210 side within the flexible wiring substrate 330, the wiring pattern may pass through the bending portion 502B due to the layout (routing) of the wiring 503. In this case, depending on the positional relationship between the element substrate 310, the bending portion 502B, and the wiring 503, the ease of bending of the flexible wiring substrate 330 and the wiring 503 therein may vary depending on the location. For example, the ease of bending often differs between flexible wiring board 330 and wiring 503a located in a portion facing an edge of element substrate 310 in a direction (Y direction) perpendicular to the direction in which bending portion 502A extends (X direction) and flexible wiring board 330 and wiring 503e located in a portion not facing an edge of element substrate 310 in the Y direction. A portion of flexible wiring board 330 in a position where element substrate 310 is not present in the same direction as the bending direction of flexible wiring board 330 (Y direction), such as wiring 503e, can be bent with a small load, has a small bending rate, and is easy to form a stable shape. On the other hand, a portion where element substrate 310 is present in the same direction as the bending direction of the bending portion (Y direction), such as wiring 503a, requires a larger load to bend, making it difficult to reduce the bending rate or form a stable position or shape.

[0028] FIG. 6(a) is a cross-sectional view taken along line VIa-VIa in FIG. 5, and FIG. 6(b) is a cross-sectional view taken along line VIb-VIb in FIG. 5. As shown in FIGS. 6(a) and 6(b), the flexible wiring board 330 has a configuration in which a wiring 503 is sandwiched between a cover film 505 and a base film 508. In the flexible wiring board 330, the wiring 503 and the cover film 505 are bonded via a cover film adhesive 506, and the wiring 503 and the base film 508 are bonded via a base film adhesive 507. In this embodiment, as an example, the flexible wiring board 330 has a configuration in which a cover film 505 having a thickness of 4 μm, a cover film adhesive 506 having a thickness of 40 μm, a wiring 503 having a thickness of 35 μm, a base film adhesive 507 having a thickness of 15 μm, and a base film 508 having a thickness of 50 μm are laminated and bonded together. In this embodiment, the wiring 503 is made of copper and formed by etching copper foil. The material of cover film 505 and base film 508 is polyimide. Cover film adhesive 506 and base film adhesive have a certain degree of hardness because they are cured, but are softer than wiring 503, cover film 505, and base film 508.

[0029] As shown in Figure 6(a), in regions where the length of flexible wiring board 330 can be made long in the same direction as the bending direction (Y direction), each layer forming flexible wiring board 330 is also long. Therefore, each layer can expand and contract over the entire length to accommodate bending of flexible wiring board 330. On the other hand, as shown in Figure 6(b), in regions where the length of flexible wiring board 330 is short, the absolute amount of deformation that each layer can accommodate by expanding and contracting is small, making it difficult to create a bent structure.

[0030] 7 is a cross-sectional view corresponding to the position VIa-VIa in FIG. 5 and FIG. 6(b) when the flexible wiring substrate 330 is bent. If the bent portion 502B is large, the space 509 also becomes large, and the size of the liquid ejection head 1 (size in the Y direction) increases. Furthermore, if the bent portion 502B on the connection member 200 side becomes large, it may affect the position of the roller (not shown in FIG. 1) that holds down the medium P, which may affect the holding width. These factors tend to lead to an increase in the size of the entire liquid ejection device.

[0031] Furthermore, even if the curvature of bent portion 502B can be reduced to make bent portion 502B smaller, there is a problem in that internal wiring 503 is more likely to crack in a bent portion with a small bending rate.

[0032] FIG. 8 is a schematic diagram showing a discharge unit 300 in the first embodiment, and shows a state in which an element substrate 310 and a flexible wiring substrate 330 are bonded to a support member 320, similar to FIG. 5, but before the flexible wiring substrate 330 is bent. In the present embodiment shown in FIG. 8, two element substrates 310 and one flexible wiring substrate 330 are arranged on one support member. Connection terminals 504 are arranged along the long sides of the element substrates 310 bonded to the support member 320 and are electrically connected to the flexible wiring substrate 330 also bonded to the support member 320. A terminal row in which multiple connection terminals 504 are lined up on one element substrate 310 is arranged along the side that does not face the other element substrate 310. Wiring 503 is also provided so as to pass between the two element substrates 310.

[0033] The portion of the flexible wiring substrate 330 that protrudes from the support member 320 is bent in a direction intersecting the direction in which a terminal row in which multiple connection terminals 504 are lined up extends, in the Y direction in this embodiment, to be connected to the electric wiring substrate 210. Furthermore, the portion of the flexible wiring substrate 330 that protrudes from the support member 320, in a region on the connection member 200 side that is not connected to the electric wiring substrate 210, is similarly bent in a direction intersecting the direction in which the terminal row extends (Y direction). FIG. 9 is an enlarged view of the vicinity of a bent portion 502B near one element substrate 310 in FIG. 8. FIG. 10(a) is a cross-sectional view taken along line XX in FIG. 9. In the liquid ejection head 1 and ejection unit 300 of the present invention, the wiring 503 is arranged such that the bent portion 502B does not have wiring 503 in a region 516 that faces the side 310a of the adjacent element substrate 310 in the bending direction (Y direction). In other words, when viewed from a direction perpendicular to the surface where the support member 320 supports the element substrate 310, the bent portion 502B bent along the first direction (X direction) does not have wiring 503 in an area facing the side 310a of the element substrate 310 in a direction (second direction, Y direction) perpendicular to the first direction. Note that in FIG. 9, the side 310a is the short side of the ejection element 310 (i.e., the side without the connection terminal 504). An adhesive (sealant) 519 is arranged in a space 509 between the support member 320 and the cover member 340.

[0034] The dashed line N in FIG. 10(a) indicates a region 516 extending from the edge of the element substrate 310 facing the end surface 514a of the flexible wiring substrate 330 to the end point 515 of the bent portion 502B (the position where the curved shape is no longer formed). In this embodiment, the traces 503 are arranged to avoid the region extending from the end surface 514a of the flexible wiring substrate 330 facing the edge 310a of the element substrate 310 in the Y direction to the end point 515 of the bent portion 502B. This configuration makes it easier to bend the flexible wiring substrate 330 in a region where the length in the bending direction of the flexible wiring substrate 330 is short. In this embodiment, as an example, the minimum width of the traces 503 is 40 μm, and the minimum pitch is 80 μm. The size of the bent portion 502B of the flexible wiring substrate 330 is R=0.8 mm, and the length of the edge 310a of the element substrate 310 is 7 mm in the X direction, and the length of the region 516 in the Y direction is 3 mm. Length L from region 516 to end surface 514b (tip surface) of flexible wiring substrate 330 was set to 4 mm. On the side of electric wiring substrate 210, flexible wiring substrate 330 can be bent to a large extent due to the configuration of the device, so the size of bent portion 502A was set to R = 2.0 mm. Note that evaluation of the size of bent portion 502 is not limited to the method using the size of R, and it may be evaluated, for example, using the size of the portion protruding from the upper surface of support member 320 in a direction parallel to the surface of support member 320.

[0035] When such a flexible wiring substrate 330 was used and bent to form the liquid ejection head 1, good printing could be obtained over a long period of time. Good printing was also confirmed in an intermittent printing durability test (repeated 1 hour of printing followed by 1 hour of standby) in a 5°C environment.

[0036] Although not shown, the same effect was confirmed in a configuration in which flexible wiring board 330 was bonded onto cover member 340, and in a configuration in which flexible wiring board 330 was bonded to support member 320 and then cover member 340 was bonded on top of that. The same effect was confirmed in a configuration in which cover member 340 was not used.

[0037] The above-described effect is not limited to a configuration in which wiring 503 is a single-layer flexible wiring board as shown in FIG. 6, but can also be applied to a configuration in which a flexible wiring board having multiple wirings inside is used.

[0038] According to the present invention described above, the flexible wiring board can be easily bent to a small size. This contributes to the miniaturization of the liquid ejection head, leading to the miniaturization of the liquid ejection device itself. Furthermore, the miniaturization of the liquid ejection device also leads to a reduction in the manufacturing cost of the device. Furthermore, since the bend of the flexible wiring board can be made smaller, the gap between the flexible wiring board and the support member also becomes smaller, and the amount of adhesive (sealant) required to fill the gap also decreases, which also leads to a reduction in manufacturing costs.

[0039] Furthermore, the fact that the flexible wiring board can be easily bent reduces the load when the flexible wiring board is bent, and this makes it possible to suppress deterioration in the reliability of the bent portion and the flexible wiring board itself, which also leads to improved reliability of the liquid ejection head.

[0040] (Second embodiment) The following description will focus on the differences from the first embodiment described above, and will omit a description of the same parts as in the first embodiment.

[0041] 11 is a schematic diagram of a discharge unit 300 according to the second embodiment, and shows a state in which an element substrate 310 and a flexible wiring substrate 330 are bonded onto a support member 320, similar to FIG. 5, before the flexible wiring substrate 330 is bent. As in the first embodiment, the element substrate 310, which has connection terminals 504 on its long side, and the flexible wiring substrate 330 are bonded to the surface of the support member 320.

[0042] In this embodiment, the opening 518 of the flexible wiring board 330 for exposing the element substrate 310 is expanded to the bent portion. In other words, when viewed from a direction perpendicular to the surface of the support member 320, the opening 518 is configured to include a region 516 that faces the edge of the element substrate in a direction perpendicular to the first direction. In FIG. 11 , the opening 518 includes the entire region 516. That is, a portion of the flexible wiring board 330 is removed to include the region 516. To facilitate bending the flexible wiring board 330, it is desirable that the flexible wiring board 330 be shaped so that the edge of the support member 320 is exposed, as shown in FIG. 11 . The configuration of this embodiment eliminates the need to bend a short portion of the flexible wiring board 330, thereby achieving an effect of making the flexible wiring board 330 even easier to bend than the configuration of FIG. 8 . The opening including the region 516 does not need to be integrated with the opening exposing the element substrate 310, as shown in FIG. 8 .

[0043] Fig. 12 is a cross-sectional view corresponding to the position XII-XII in Fig. 11 when flexible wiring board 330 is bent. Fig. 12 also shows cover member 340. In the area where flexible wiring board 330 has been cut away, space 509 is formed between support member 320 and cover member 340, and adhesive (sealant) 519 can be filled using capillary force. In addition, the presence of cover member 340 makes it difficult for a large amount of ink to adhere to space 509.

[0044] In this embodiment, as an example, the minimum width of the wiring 503 is 40 μm, and the minimum pitch is 90 μm. The size of the bent portion 502B of the flexible wiring substrate 330 is R=0.8 mm, the length of the side 310a of the element substrate 310, which is the length of the region K in the X direction, is 7 mm, and in the region 516, 2.5 mm of the flexible wiring substrate 330 is removed in the Y direction, leaving 0.5 mm. The length L from the region 516 to the end of the flexible wiring substrate is 4.0 mm.

[0045] On the electrical wiring board 210 side, the flexible wiring board 330 itself covering the area 516 was removed because ink is less likely to adhere to it due to the configuration of the device. When the liquid ejection head 1 was constructed with this type of ejection unit 300 configuration, good printing could be obtained over a long period of time. Good printing was also confirmed in an intermittent printing durability test (1 hour of printing followed by 1 hour of standby) in a 5°C environment.

[0046] (Third embodiment) The following description will focus on the differences from the first and second embodiments, and will omit a description of the similarities.

[0047] 13 is a schematic diagram of a discharge unit 300 according to a third embodiment, and shows a state in which an element substrate 310 and a flexible wiring substrate 330 are bonded onto a support member 320, similar to FIG. 5, before the flexible wiring substrate 330 is bent. As in the first embodiment, the element substrate 310, which has connection terminals 504 on its long side, and the flexible wiring substrate 330 are bonded to the surface of the support member 320.

[0048] In the third embodiment, the flexible wiring board 330 has a shape similar to that of the first embodiment at the bent portion 502A, and a shape similar to that of the second embodiment at the bent portion 502B.

[0049] Although the outer surfaces of cover film 505 and base film 508 of flexible wiring substrate 330 have high ink resistance, the interfaces of each layer via the adhesive layer are susceptible to erosion by ink. For this reason, it is desirable to protect the end face (edge) of flexible wiring substrate 330 facing element substrate 310 with adhesive 519 or a sealant. On the other hand, if the protected area of ​​the end face of flexible wiring substrate 330 is large, this is likely to lead to a deterioration in the lead time of the manufacturing process and an increase in costs.

[0050] The present embodiment shown in FIG. 13 takes the above-mentioned problems into consideration, and the connecting member 200 side of the flexible wiring board 330 uses the shape of the first embodiment, and the electric wiring board 210 side uses the shape of the second embodiment.

[0051] At the bent portion 502B on the connecting member 200 side, ink is likely to adhere from the ink supply port 201, and it is therefore desirable to seal the space 509. Therefore, in order to reduce the volume of the space 509 and thereby reduce the amount of adhesive (sealant) to be filled, the wiring 503 is arranged to avoid the area 516, without reducing the area where the flexible wiring substrate 330 overlaps with the support member 320, as in the first embodiment. The ink resistance of the flexible wiring substrate 330 is higher than that of the adhesive (sealant), and therefore the ink resistance reliability of the liquid ejection head is maintained.

[0052] On the other hand, because the possibility of ink adhering to the bent portion 502A on the electric wiring board 210 side is lower than that on the connecting member 200 side due to the configuration of the liquid ejection device 50, it is sufficient to fill it with a minimum amount of adhesive (sealant) 519. For this reason, as in the second embodiment, the flexible wiring board 330 is cut out to prioritize ease of bending.

[0053] When the liquid ejection head 1 was configured with this type of ejection unit 300, good printing could be obtained over a long period of time. Good printing was also confirmed in an intermittent printing durability test (1 hour of printing followed by 1 hour of standby) in a 5°C environment.

[0054] (Fourth embodiment) The following description will focus on the differences from the above-described embodiment, and will omit a description of the same parts as in the above-described embodiment.

[0055] FIG. 14 is a schematic diagram of a discharge unit 300 according to a fourth embodiment of the present invention, and shows a state in which an element substrate 310 and a flexible wiring substrate 330 are bonded onto a support member 320, similar to FIG. 5, before the flexible wiring substrate 330 is bent.

[0056] In the configuration of FIG. 14 , among the multiple wirings 503 of flexible wiring substrate 330, wiring 503c closest to the outer peripheral edge of flexible wiring substrate 330 and wiring 503d adjacent to the edge of the opening are dummy wirings that are not connected to connection terminals 504. This makes it possible to suppress a decrease in reliability due to ink penetration from the edge of flexible wiring substrate 330. Note that only one of wirings 503d and 503c may be a dummy wiring. Alternatively, both wirings 503d and 503c may be dummy wiring. Furthermore, while FIG. 14 shows a configuration in which only bent portion 502B on the connection member 200 side has a dummy wiring, only bent portion 502A on the electrical wiring substrate 210 side may have a dummy wiring, or both bent portions 502A and 502B may be dummy wiring.

[0057] Ground wiring may be provided instead of the dummy wiring, which similarly has the effect of suppressing a decrease in reliability due to ink penetration from the edge of the flexible wiring substrate 330. This is because the ground wiring is not subjected to a potential, and therefore migration does not occur from the edge.

[0058] This embodiment may be configured such that a flexible wiring substrate 330 without wiring 503 exists in the region 516, such as the bending portion 502B corresponding to the element substrate 310 on the left side of Figure 14, or such that the flexible wiring substrate 330 has an opening so as to include the region 516, such as the bending portion 502B corresponding to the element substrate 310 on the right side of Figure 14.

[0059] (Fifth embodiment) The following description will focus on the differences from the above-described embodiment, and will omit a description of the same parts as in the above-described embodiment.

[0060] Fig. 15(a) is a partial schematic diagram of a discharge unit 300 showing a fifth embodiment of the present invention, and is an enlarged view of a bending portion 502A. Fig. 15(a) shows a state in which an element substrate 310 and a flexible wiring substrate 330 are joined onto a support member 320, as in Fig. 5, before the flexible wiring substrate 330 is bent. Unlike the first to fourth embodiments, in the configuration of this embodiment, the element substrate 310 has connection terminals 504 on its short sides. In this case, as in the comparative example shown in Fig. 5, if wiring 503 is arranged in a region facing the element substrate 310 in the bending direction (Y direction) of the bending portion 502A, it may be difficult to form the bending portion 502A.

[0061] Therefore, in this embodiment, when wiring 503 is routed to the electric wiring board 210 side, it is arranged along the extending direction of bent portion 502A (X direction) up to a region in the Y direction that does not face the element substrate 310, and then it is arranged to extend in the bending direction of bent portion 502A (Y direction) toward the electric wiring board side. Fig. 15(b) is a cross-sectional view taken along XVb-XVb in Fig. 15(a). As can be seen from Fig. 15(b), since wiring (copper foil) 503, which has a significant effect on the bendability of flexible wiring board 330, is not bent, it is possible to make bent portion 502A small with a small load.

[0062] On the other hand, as in the comparative example shown in FIG. 16, if the wiring 503 is arranged so as to be bent in the Y direction without extending in the X direction to an area that does not face the element substrate 310, it becomes difficult to bend the bending portion 502B with a small load, and it becomes difficult to create a stable bent shape.

[0063] 15, since the wiring 503 is arranged along the bending portion 502A (along the X direction), when flexible wiring substrate 330 is bent, the bending tends to start from edge 510 of wiring 305 in the bending direction (Y direction), which may make it difficult to create a stable bending shape and position. Furthermore, if edge 510 is intentionally arranged in a position close to bending portion B502 so as to create a bending shape starting from edge 510, edge 510 may act like a blade and dig into cover film adhesive 506 in areas where tension is applied to flexible wiring substrate 330, causing cracks and possibly damaging or cracking cover film 505. Even if the wiring 503 is arranged along the bending portion 502B as in the configuration shown in Figure 9, if the wiring 503 is arranged in a region closer to the tip of the flexible wiring substrate 330 than the bending portion 502B rather than in a region adjacent to the short side of the element substrate 310, a length that allows the flexible wiring substrate 330 to expand and contract can be ensured, and cracks originating from the edge of the wiring 503 are less likely to occur.

[0064] (Sixth embodiment) The following description will focus on the differences from the above-described embodiment, and will omit a description of the same parts as in the above-described embodiment.

[0065] In the first to fifth embodiments described above, one wiring 503 is connected to one connection terminal 504, and each individual wiring 503 is routed to the electric wiring board 210. However, the configuration of the connection terminals and wiring of the present invention is not limited to this, and the present invention can be suitably used even in a configuration in which, for example, multiple wirings 503 are grouped together within the flexible wiring board 330. Fig. 17 is a partial schematic diagram of a discharge unit 300 showing a sixth embodiment of the present invention. The configuration shown in Fig. 17 has wiring 503f in which multiple wirings 503 connected to multiple connection terminals 504 are grouped together.

[0066] In this embodiment, a voltage of 24 V is applied as the drive voltage for the ejection elements, but wiring resistance can be reduced by bundling multiple wires together. On the other hand, providing wiring that bundles multiple wires together may lead to a decrease in the flexibility of the flexible wiring substrate 330. For this reason, when adopting a configuration in which multiple wires are bundled together, it is desirable to use a configuration in which the wires for power supply are bundled together and the wires for drive signals for the ejection elements are not bundled together.

[0067] The present disclosure includes the following embodiments.

[0068] (Configuration 1) an element substrate having elements driven by a drive signal and ejection ports that eject liquid when the elements are driven; a flexible wiring board having wiring for supplying the drive signal to the element; a support member that supports the element substrate and the flexible wiring substrate on a first surface; In a liquid ejection head having the flexible wiring board has a bent portion bent along one side of the support member that extends in a first direction, The liquid ejection head, wherein when viewed from a direction perpendicular to the first surface, the bent portion does not have the wiring in an area facing a side of the element substrate in a second direction orthogonal to the first direction.

[0069] (Configuration 2) an element substrate having elements driven by a drive signal, ejection ports that eject liquid when the elements are driven, and terminals for receiving the drive signal from an external device; a flexible wiring board having wiring for supplying the drive signal to the element; a support member that supports the element substrate and the flexible wiring substrate on a first surface; In a liquid ejection head having the flexible wiring board has a bent portion bent along one end of the support member extending in a first direction, The liquid ejection head, wherein when viewed from a direction perpendicular to the first surface, the bent portion has an opening including a region facing a side of the element substrate in a second direction orthogonal to the first direction.

[0070] (Configuration 3) a housing that supports the support member; an electric wiring board disposed on a first side surface of the housing in the second direction and electrically connected to the flexible wiring board; 3. The liquid ejection head according to claim 1, further comprising:

[0071] (Configuration 4) the element substrate has a plurality of terminals for electrical connection to the wiring, 4. The liquid ejection head according to configuration 3, wherein the plurality of terminals are arranged side by side in a direction intersecting the first direction.

[0072] (Configuration 5) The wiring is a first wiring extending from a connection portion with the terminal to the electric wiring board side; The liquid ejection head according to configuration 4, further comprising: a second wiring extending from a connection portion with the terminal to a side opposite to the electric wiring board, and then extending toward the electric wiring board.

[0073] (Configuration 6) The liquid ejection head according to any one of configurations 1 to 5, wherein the flexible wiring board has an opening in which the element substrate is disposed.

[0074] (Configuration 7) 7. The liquid ejection head according to any one of configurations 3 to 6, wherein the bent portion is located on the side of the electrical wiring board in the second direction.

[0075] (Configuration 8) 7. The liquid ejection head according to any one of configurations 3 to 7, wherein the bent portion is located on the side opposite to the electrical wiring board in the second direction.

[0076] (Configuration 9) The liquid ejection head according to any one of configurations 3 to 8, wherein the bent portions are provided on both sides of the support member in the second direction.

[0077] (Configuration 10) A liquid ejection head described in any one of configurations 1 to 3, wherein the element substrate has the ejection port and a terminal for electrically connecting to the wiring on the surface opposite to the surface facing the first surface.

[0078] (Configuration 11) 11. The liquid ejection head according to any one of configurations 1 to 10, further comprising a resin member between the flexible wiring board and a side surface of the support member that intersects with the first surface.

[0079] (Configuration 12) The liquid ejection head according to configuration 4, further comprising a dummy wiring or a ground wiring arranged corresponding to the terminal arranged at the end of the plurality of terminals.

[0080] (Configuration 13) 13. The liquid ejection head according to any one of configurations 1 to 12, further comprising a cover member disposed on the surface of the flexible wiring board opposite to the support member.

[0081] (Configuration 14) A liquid ejection head described in any one of configurations 1 to 13, wherein the element substrate has a first element substrate and a second element substrate arranged side by side in the first direction, and the wiring is arranged to pass between the first element substrate and the second element substrate.

[0082] (Configuration 15) the first element substrate has a terminal row in which a plurality of terminals for electrical connection with the wiring are arranged in a direction intersecting the first direction, 15. The liquid ejection head according to configuration 14, wherein the terminal array is arranged along a side of the first element substrate that does not face the second element substrate.

[0083] (Configuration 16) 16. A liquid ejection device comprising the liquid ejection head according to any one of configurations 1 to 15, wherein the liquid ejection head is configured to perform a scanning movement. [Explanation of symbols]

[0084] 1 Liquid ejection head 50 Liquid dispensing device 54 Circulation Unit 110 Flow path member 200 Connecting member 210 Electrical wiring board 300 Discharge Unit 310 Ejection element substrate 320 Support member 330 Flexible wiring board 340 Cover member 502A, 502B bent part 503 Wiring 504 connection terminal

Claims

1. an element substrate having elements driven by a drive signal and ejection ports that eject liquid when the elements are driven; a flexible wiring board having wiring for supplying the drive signal to the element; a support member that supports the element substrate and the flexible wiring substrate on a first surface; In a liquid ejection head having the flexible wiring board has a bent portion bent along one side of the support member that extends in a first direction, When viewed from a direction perpendicular to the first surface, the bent portion does not have the wiring in an area facing a side of the element substrate in a second direction orthogonal to the first direction.

2. an element substrate having elements driven by a drive signal, ejection ports that eject liquid when the elements are driven, and terminals for receiving the drive signal from an external device; a flexible wiring board having wiring for supplying the drive signal to the element; a support member that supports the element substrate and the flexible wiring substrate on a first surface; In a liquid ejection head having the flexible wiring board has a bent portion bent along one end of the support member extending in a first direction, When viewed from a direction perpendicular to the first surface, the bent portion has an opening including a region facing a side of the element substrate in a second direction orthogonal to the first direction.

3. a housing that supports the support member; an electric wiring board disposed on a first side surface of the housing in the second direction and electrically connected to the flexible wiring board; The liquid ejection head according to claim 1 or 2, comprising:

4. the element substrate has a plurality of terminals for electrical connection to the wiring, The liquid ejection head according to claim 3 , wherein the plurality of terminals are arranged side by side in a direction intersecting the first direction.

5. The wiring is a first wiring extending from a connection portion with the terminal to the electric wiring board; The liquid ejection head according to claim 4 , further comprising: a second wiring extending from a connection portion with the terminal to a side opposite to the electric wiring board, and then extending to the electric wiring board side.

6. The liquid ejection head according to claim 1 , wherein the flexible wiring board has an opening in which the element substrate is disposed.

7. The liquid ejection head according to claim 3 , wherein the bent portion is located on the side of the electrical wiring board in the second direction.

8. The liquid ejection head according to claim 3 , wherein the bent portion is located on the opposite side to the electrical wiring board in the second direction.

9. The liquid ejection head according to claim 3 , wherein the bent portions are provided on both sides of the support member in the second direction.

10. 3. The liquid ejection head according to claim 1, wherein the element substrate has the ejection ports and terminals for electrical connection to the wiring on a surface opposite to the surface facing the first surface.

11. The liquid ejection head according to claim 1 , further comprising a resin member between the flexible wiring board and a side surface of the support member that intersects with the first surface.

12. The liquid ejection head according to claim 4 , further comprising a dummy wiring or a ground wiring arranged corresponding to the terminal arranged at the end of the plurality of terminals.

13. 3. The liquid ejection head according to claim 1, further comprising a cover member disposed on a surface of said flexible wiring board opposite to said support member.

14. 3. A liquid ejection head as described in claim 1 or 2, wherein the element substrate has a first element substrate and a second element substrate arranged side by side in the first direction, and the wiring is arranged to pass between the first element substrate and the second element substrate.

15. the first element substrate has a terminal row in which a plurality of terminals for electrical connection with the wiring are arranged in a direction intersecting the first direction; The liquid ejection head according to claim 14 , wherein the terminal array is arranged along a side of the first element substrate that does not face the second element substrate.

16. 3. A liquid ejection device comprising the liquid ejection head according to claim 1 or 2, wherein the liquid ejection head is configured to perform a scanning movement.

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