Liquid ejection head and manufacturing method thereof

Abstract

To suppress deformation caused by temperature distribution of a passage member with a common supply passage and common recovery passage included, and discharge liquid with high precision.SOLUTION: A liquid discharge head includes: a recording element substrate; a passage member 210 which has a common supply passage 211 and a common recovery passage 212 in which liquid at a temperature higher than in the common supply passage 211 flows; and a support member 81 which supports the passage member 210. The common supply passage 211 and common recovery passage 212 extend along a longer direction of the passage member 210 and are formed side by side in a shorter direction of the passage member 210. A position in the longer direction of the passage member 210 is defined at a center part in the longer direction, a position in a shorter direction is defined at a side surface 210A positioned on a common supply passage 211 side in the shorter direction out of side surfaces extending in the longer direction, and a position in a thickness direction with respect to the support member 81 is defined and fixed at least at the center part in the longer direction.SELECTED DRAWING: Figure 9

Description

[Technical field]

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

[0002] In recent years, high-speed recording is required for liquid ejection devices used for commercial and industrial purposes such as the production of retail photos, the drawing of electronic circuits, the production of panel displays, etc. In order to achieve high-speed recording, a line-type liquid ejection head may be configured in which a plurality of recording element substrates are arranged in a row, the length in the longitudinal direction (recording width) is equal to or greater than the recorded width of the recording medium, and a large number of ejection ports are provided.

[0003] Patent documents 1 and 2 disclose a configuration in which a common supply flow path and a common recovery flow path are provided across multiple recording element substrates of a liquid ejection head, and liquid is supplied to and recovered from each recording element substrate. Patent document 1 discloses a configuration in which a heating means for heating liquid is provided on the recording element substrate to achieve high-quality recording. Patent document 2 discloses a configuration in which each recording element substrate is provided with a protruding portion at its end, and the protruding portion is fixed by a screw to a support member that supports each recording element substrate, thereby reducing positional deviation of the ejection orifices. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-213871 A [Patent Document 2] JP 2020-49778 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the invention described in Patent Document 1, the liquid supplied to the recording element substrate from the common supply flow path is heated by a heating means, and then at least a part of the heated liquid flows into the common recovery flow path without being discharged to the outside. As a result, the liquid flowing through the common recovery flow path becomes hotter than the liquid flowing through the common supply flow path, and a temperature distribution occurs. This temperature distribution causes deformation of the flow path member in which the common supply flow path and the common recovery flow path are formed. When the flow path member is deformed, the positions of the recording element substrates arranged to overlap the flow path member are shifted, and the landing position accuracy of the droplets discharged from the recording element substrate decreases, resulting in a problem that the quality of recording by liquid discharge decreases. This problem is particularly noticeable in long line-type liquid discharge heads for high-speed recording, and is difficult to solve even with the configuration described in Patent Document 2 or a configuration provided with a mechanism for finely adjusting the positions of the liquid discharge head and the recording element substrate.

[0006] In view of the above-mentioned problems, the present invention aims to provide a liquid ejection head and a manufacturing method thereof that are capable of ejecting liquid with high precision by suppressing deformation caused by temperature distribution in a flow path member in which a common supply flow path and a common recovery flow path are formed. [Means for solving the problem]

[0007] The liquid ejection head of the present invention includes a recording element substrate having an ejection port for ejecting liquid, a common supply flow path that supplies liquid to the recording element substrate, and a common recovery flow path that recovers liquid from the recording element substrate and through which a liquid having a higher temperature than the liquid flowing through the common supply flow path flows. are formed along the longitudinal direction of the flow path member and are arranged side by side in the lateral direction of the flow path member. A flow path member and a support member that supports the flow path member, the flow path member has a plurality of fixing portions fixed to the support member and a positioning portion that is positioned with respect to the support member, Among the plurality of fixing portions, a fixing portion located at a center portion in the longitudinal direction has a positioning elongated hole having a major axis in the short side direction that defines a position in the longitudinal direction with respect to the support member, and includes a fixing portion provided on a side of the flow path member extending in the longitudinal direction that is located on the common recovery flow path side in the short side direction of the flow path member, and a fixing portion having a screw through hole that fixes the support member while defining a position in a thickness direction, Among the plurality of fixing portions, fixing portions located on both sides in the longitudinal direction have a screw through hole having an elongated hole shape with a long axis in the longitudinal direction, the positioning portion is provided on a side surface of the flow path member that is located on the common supply flow path side in a short side direction of the flow path member, among side surfaces extending in the longitudinal direction of the flow path member, and is located on both side portions of the flow path member in the longitudinal direction; the support member has a positioning pin arranged at a position facing the positioning elongated hole and a butting portion facing the positioning portion in the short side direction, the positioning pin is inserted into the positioning elongated hole, and holds the flow path member so as to be movable relative to the support member in the short side direction within a range in which the positioning pin is positioned within the positioning elongated hole; The flow path member is fixed to the support member by a screw that is screwed into the support member through the screw through hole. It is characterized by: Effect of the Invention

[0008] According to the present invention, in the liquid ejection head, deformation caused by temperature distribution in the flow path member in which the common supply flow path and the common recovery flow path are formed is suppressed, making it possible to eject liquid with high accuracy. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating the configuration of a liquid ejection device including a liquid ejection head according to an embodiment of the present invention. [Diagram 2] 2 is a schematic diagram of a liquid circulation path of the liquid ejection device shown in FIG. [Diagram 3] FIG. 2 is a perspective view of a liquid ejection head of the liquid ejection device shown in FIG. [Figure 4] FIG. 4 is an exploded perspective view of the liquid ejection head shown in FIG. [Diagram 5] 4 is a cross-sectional view of a part of the liquid ejection head shown in FIG. 3 cut along the short side direction. [Figure 6] 4 is an exploded perspective view of a flow path member and a support member of the liquid ejection head shown in FIG. 3 and a perspective view of the assembled state. [Figure 7] 7 is a schematic plan view of a flow path member and a schematic plan view of a support member shown in FIG. 6. [Figure 8] 8 is a schematic plan view showing a fixed state of the flow path member and the support member shown in FIG. 7. FIG. [Figure 9] 9 is a schematic plan view of the flow path member and the support member shown in FIG. 8, illustrating a deformed state of the flow path member. FIG. [Figure 10] 11 is a schematic plan view of a flow path member and a support member of a comparative example, showing a deformation state of the flow path member. FIG. [Figure 11] FIG. 11 is a cross-sectional view of a part of a liquid ejection head according to another embodiment of the present invention, cut along the short side direction. [Figure 12] 12A and 12B are schematic plan views of a flow path member and a support member of the liquid ejection head shown in FIG. [Figure 13] 13 is a schematic plan view showing a fixed state of the flow path member and the support member shown in FIG. 12. FIG. [Figure 14]14 is a schematic plan view of the flow path member and the support member shown in FIG. 13, illustrating a deformed state of the flow path member. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the following description does not limit the scope of the present invention. The embodiment described below relates to a thermal type liquid ejection head in which a heating element, which is an energy generating element, generates thermal energy, and generates bubbles by the heat to eject liquid. However, the present invention can also be applied to liquid ejection heads that adopt a piezoelectric type or other various liquid ejection types. In addition, the embodiment described below relates to a liquid ejection device (inkjet recording device) in a form in which liquid such as ink is circulated between a tank and a liquid ejection head, but the present invention can also be applied to liquid ejection devices in other forms. For example, a configuration in which two tanks are provided on the upstream side and downstream side of the liquid ejection head, and liquid is caused to flow from one tank to the other tank to cause the liquid in the pressure chamber to flow without circulating the liquid may be used. Furthermore, the liquid ejection head of the embodiment described below is a so-called line type liquid ejection head that corresponds to the recording width of the recording medium and has a recording width equal to or greater than this recording width. However, the present invention can also be applied to a so-called serial type liquid ejection head that ejects liquid while scanning the recording medium. An example of a serial type liquid ejection head is a liquid ejection head equipped with a recording element substrate for black ink and a recording element substrate for color inks. A plurality of recording element substrates are arranged in a line with some of them overlapping each other so that the ejection ports overlap in the ejection port row direction, to produce a short liquid ejection head shorter than the recording width of the recording medium, and the liquid ejection head may be configured to scan the recording medium.

[0011] [Explanation of the basic configuration of the liquid ejection device] FIG. 1 shows a schematic configuration of an inkjet recording device 1000 (hereinafter also referred to as a recording device) which performs recording by discharging liquid ink, as an example of a liquid discharge device including a liquid discharge head according to the present invention. The recording device 1000 is a line-type recording device which includes a conveying unit 1 for conveying a recording medium 2 and a long line-type liquid discharge head 3 extending in a direction substantially perpendicular to the conveying direction of the recording medium 2, and performs continuous recording in one pass while conveying the recording medium 2 continuously or intermittently. The recording medium 2 is not limited to cut paper, but may be continuous roll paper. The liquid discharge head 3 is an inkjet recording head capable of full-color recording by discharging four colors of liquid ink, CMYK (cyan, magenta, yellow, black). The liquid discharge head 3 is fluidly connected to a liquid supplying means which constitutes a supply path for supplying liquid to the liquid discharge head 3 as described later, a main tank 1006, and a buffer tank 1003 (see FIG. 2). In addition, an electric control unit which transmits power and discharge control signals to the liquid discharge head 3 is electrically connected to the liquid discharge head 3. The liquid paths and electrical signal paths within the ejection head 3 will be described later.

[0012] (Explanation of the circulation route) FIG. 2 is a schematic diagram showing a circulation path, which is a liquid path of the recording apparatus of this embodiment. FIG. 2 shows a state in which the liquid ejection head 3 is fluidly connected to a first circulation pump 1002, a second circulation pump 1004, a third circulation pump 1001, a buffer tank 1003, and the like. In FIG. 2, for the sake of simplicity, only a liquid path through which one of the four colors of liquid ink, CMYK, flows is shown. The liquid ejection head 3 mainly includes a liquid ejection unit 300, a liquid supply unit 220, and a negative pressure control unit 230. The buffer tank 1003, which is a sub-tank connected to the main tank 1006 via a refill pump 1005, has an air communication port (not shown) that communicates the inside and outside of the buffer tank 1003, and is capable of discharging air bubbles in the liquid to the outside. When liquid is consumed in the liquid ejection head 3 by ejecting (discharging) liquid from the ejection port 10a (see Figures 3 and 5) of the liquid ejection head 3 for recording, suction recovery, etc., the refill pump 1005 transfers the consumed amount of liquid from the main tank 1006 to the buffer tank 1003.

[0013] The first circulation pump 1002 has a function of drawing liquid from the liquid connection portion 111 of the liquid ejection head 3 and flowing it to the buffer tank 1003. As the first circulation pump 1002, a positive displacement pump having a quantitative liquid delivery capacity, specifically, for example, a tube pump, a gear pump, a diaphragm pump, a syringe pump, or the like, is preferable. However, a pump having a general constant flow valve or a relief valve arranged at the pump outlet to ensure a constant flow rate can also be used as the first circulation pump 1002. When the liquid ejection head 3 is driven, a certain amount of liquid flows through the common recovery flow path 212 by the first circulation pump 1002. It is preferable that the flow rate of the liquid is set to a flow rate or higher that does not affect the recording image quality due to the temperature difference between each recording element substrate 10 of the liquid ejection unit 300. However, if the flow rate is too large, the negative pressure difference between each recording element substrate 10 becomes too large due to the influence of pressure loss in the flow path in the liquid ejection unit 300, and density unevenness occurs in the recorded image formed by liquid ejection. Therefore, it is preferable to set the flow rate taking into consideration the temperature difference and negative pressure difference between the recording element substrates 10.

[0014] The negative pressure control unit 230 is provided in a path between the second circulation pump 1004 and the liquid ejection unit 300. The negative pressure control unit 230 has a function of operating to maintain the pressure downstream of the negative pressure control unit 230 (the liquid ejection unit 300 side) within a preset constant pressure range even when the flow rate of the circulation path varies due to a difference in the duty of printing. Any mechanism may be used as the two pressure adjustment mechanisms constituting the negative pressure control unit 230 as long as it can suppress the pressure fluctuation on the downstream side within a constant pressure range centered on a predetermined set pressure. As an example of the pressure adjustment mechanism, a so-called pressure reducing regulator can be adopted. When a pressure reducing regulator is used as the pressure adjustment mechanism, it is preferable to pressurize the upstream side of the negative pressure control unit 230 via the liquid supply unit 220 by the second circulation pump 1004, as shown in FIG. 2. This can suppress the effect of the head pressure of the buffer tank 1003 on the liquid ejection head 3, thereby increasing the degree of freedom in the layout of the buffer tank 1003 in the recording apparatus 1000. The second circulation pump 1004 may be a turbo pump, a positive displacement pump, or the like, as long as it has a head pressure equal to or greater than a certain value within the range of the ink circulation flow rate when the liquid ejection head 3 is driven. Specifically, a diaphragm pump or the like can be used as the second circulation pump 1004. Also, instead of the second circulation pump 1004, it is possible to use, for example, a water head tank arranged with a certain water head difference with respect to the negative pressure control unit 230.

[0015] 2, the negative pressure control unit 230 includes two pressure adjustment mechanisms, each of which is set to a different control pressure. The pressure adjustment mechanism H on the relatively high pressure side is connected to the common supply of the flow path member 210 of the liquid ejection unit 300 via the liquid supply unit 220. Flow path 211 is connected to one end of the common supply Flow pathThe other end of 211 is connected to the third circulation pump 1001 via a liquid supply unit 220. The relatively low pressure side pressure adjustment mechanism L is connected to one end of the common recovery flow path 212 of the flow path member 210 of the liquid ejection unit 300 via the liquid supply unit 220. Flow path The other end of 212 is connected to the first circulation pump 1002 via the liquid supply unit 220. The flow path member 210 of the liquid ejection unit 300 is provided with an individual supply flow path 213a and an individual recovery flow path 213b. The individual supply flow path 213a is a common supply Flow path 211 and each recording element substrate 10. The individual recovery flow paths 213b are connected to the common recovery flow path 212 and each recording element substrate 10. Therefore, a part of the liquid caused to flow by the first circulating pump 1002 flows from the common supply flow path 211 through an internal flow path of the recording element substrate 10 to the common recovery flow path 212 (shown by an arrow in FIG. 2). This is because a pressure difference is provided between the pressure adjustment mechanism H connected to the common supply flow path 211 and the pressure adjustment mechanism L connected to the common recovery flow path 212, and the first circulating pump 1002 is connected to the common recovery flow path 212 rather than to the common supply flow path 211.

[0016] In this way, in the liquid ejection unit 300, a flow of liquid passing through the common recovery flow path 212 and a flow of liquid passing through each recording element substrate 10 from the common supply flow path 211 to the common recovery flow path 212 are generated. Therefore, heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the flow from the common supply flow path 211 to the common recovery flow path 212. Furthermore, with this configuration, when liquid is ejected from the liquid ejection head 3, a flow of liquid can be generated even in ejection ports and pressure chambers that are not ejecting liquid. This makes it possible to suppress the viscosity of the liquid in the ejection ports and pressure chambers, and also makes it possible to discharge the viscosity-increased liquid and foreign matter in the liquid to the common recovery flow path 212. Therefore, the liquid ejection head 3 of this embodiment is capable of high-speed, high-quality recording.

[0017] (Description of the configuration of the liquid ejection head) The configuration of the liquid ejection head 3 according to this embodiment will be described. FIG. 3(a) and FIG. 3(b) are perspective views of the liquid ejection head 3 according to this embodiment. The liquid ejection head 3 is a line-type liquid ejection head in which 15 recording element substrates 10, each capable of ejecting liquid inks of multiple colors, are arranged in a straight line (in-line). Each recording element substrate 10 has a plurality of ejection ports 10a, and may be arranged on a flow path member with at least some of the ejection ports overlapping each other. As shown in FIG. 3(a), the liquid ejection head 3 includes a plurality of recording element substrates 10, a plurality of flexible wiring substrates 40, and an electric wiring substrate 90 electrically connected to each recording element substrate 10 via each flexible wiring substrate 40. The electric wiring substrate 90 includes a signal input terminal 91, a power supply terminal 92, and a connection terminal 93 (see FIG. 4). The signal input terminal 91 and the power supply terminal 92 are electrically connected to a control unit of the main body of the recording apparatus, and supply an ejection drive signal and power required for ejection to the recording element substrate 10, respectively. By consolidating the wiring by the electric circuit in the electric wiring board 90, the number of signal input terminals 91 and power supply terminals 92 can be reduced compared to the number of recording element boards 10. This reduces the number of electrical connection parts that need to be removed when assembling the liquid ejection head 3 to the recording device body or replacing the liquid ejection head. The flexible wiring board 40 connected to the recording element board 10 is connected to the connection terminal 93 of the electric wiring board 90. As shown in FIG. 3(b), the liquid connection part 111 provided on one side of the liquid ejection head 3 is connected to the liquid path of the recording device body. This allows the liquid ink to be supplied from the liquid path of the recording device body to the liquid ejection head 3, and the liquid ink that has passed through the inside of the liquid ejection head 3 is collected to the liquid path of the recording device body. In this way, the liquid ink of each color can circulate through the liquid path of the recording device body and the liquid path of the liquid ejection head 3.

[0018] FIG. 4 shows an exploded perspective view of each member constituting the liquid ejection head 3. In this liquid ejection head 3, a liquid ejection unit 300, a liquid supply unit 220, and an electric wiring board 90 are attached to a housing 80. The liquid supply unit 220 is provided with a liquid connection section 111 (see FIG. 3). Inside the liquid supply unit 220, filters 221 (for example, for four colors) are provided that communicate with the openings of the liquid connection section 111 in order to remove foreign matter from the liquid to be supplied. The liquid that has passed through the filters 221 is supplied to negative pressure control units 230 provided on the liquid supply unit 220 in correspondence with each color. The negative pressure control units 230 are units that include pressure adjustment valves for each color. The negative pressure control units 230 greatly attenuate changes in pressure loss inside the liquid path (the supply path upstream of the liquid ejection head 3) of the recording device body that occur with fluctuations in the flow rate of the liquid, by the action of valves and spring members provided inside each unit. Furthermore, the negative pressure control unit 230 is capable of stabilizing changes in the negative pressure downstream of the negative pressure control unit 230 (the liquid ejection unit 300 side) within a certain range by the action of a valve, a spring member, etc. Two pressure adjustment mechanisms H, L set to different control pressures for each color are built into the negative pressure control unit 230 for each color, as shown in Fig. 2. The high-pressure side pressure adjustment mechanism H communicates with the common supply flow path 211 in the liquid ejection unit 300 via the liquid supply unit 220, and the low-pressure side pressure adjustment mechanism L communicates with the common recovery flow path 212 via the liquid supply unit 220.

[0019] The housing 80 includes a liquid discharge unit support portion (hereinafter also referred to as a support member) 81 and an electric wiring board support portion 82, and supports the liquid discharge unit 300 and the electric wiring board 90 while ensuring the rigidity of the liquid discharge head 3. The electric wiring board support portion 82 is fixed to the support member 81 by screwing and supports the electric wiring board 90. The support member 81 corrects warping and deformation of the liquid discharge unit 300, ensures the relative positional accuracy of the multiple recording element substrates 10, and suppresses streaks and unevenness in the recorded image due to liquid discharge. For this reason, it is preferable that the support member 81 has sufficient rigidity and is preferably made of a metal material such as stainless steel or aluminum, or a ceramic such as alumina. The support member 81 has openings 83 and 84, and a joint rubber 100 is inserted into the openings 83 and 84. The liquid supplied from the liquid supply unit 220 is led to the flow path member 210 of the liquid discharge unit 300 through the joint rubber 100.

[0020] The liquid ejection unit 300 includes a plurality of ejection modules 200 and a flow path member 210. The ejection module 200 includes a recording element substrate 10 and an element substrate support plate 30 (see FIG. 5) that supports the recording element substrate 10. A cover member 130 is attached to the surface of the liquid ejection unit 300 on the recording medium side. The flow path member 210 is configured by stacking a plurality of plate-shaped members in the thickness direction, and is a member for distributing the liquid supplied from the liquid supply unit 220 to each ejection module 200 and returning the liquid returned from the ejection module 200 to the liquid supply unit 220. The flow path member 210 is fixed to the support member 81 by screws, which suppresses warping and deformation of the flow path member 210. For this reason, it is desirable that the linear expansion coefficient of the material of the support member 81 is equal to or lower than the linear expansion coefficient of the material of the flow path member 210. It is desirable that the flow path member 210 is made of a material that is resistant to corrosion by liquid and has a low linear expansion coefficient. As the material of the flow path member 210, for example, a composite resin material with a base material of alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), PSF (polysulfone), or modified PPE (polyphenylene ether) can be suitably used. The composite resin material may be the above-mentioned base material to which an inorganic filler such as silica fine particles or fiber is added. The flow path member 210 may be formed by laminating a plurality of plate-shaped members and adhering them to each other. In addition, when a composite resin material is selected as the material of the flow path member 210, the flow path member 210 may be formed by laminating a plurality of plate-shaped members and fusing them to each other. As shown in FIG. 4, the cover member 130 is a frame-shaped member provided with a long opening 131. The recording element substrate 10 and the sealant (not shown) included in the discharge module 200 are exposed from the opening 131. The frame portion surrounding the opening 131 functions as a contact surface of a cap member that caps the liquid discharge head 3 when waiting for liquid discharge. For this reason, it is preferable to apply a coating material such as an adhesive, sealant, or filler around the periphery of the opening 131 so that, when capping, the coating material fills in any irregularities or gaps on the ejection port surface of the liquid ejection unit 300 to form a closed space.

[0021] FIG. 5 is a diagram showing a cross section of the liquid ejection head 3 of this embodiment cut along the short side. As shown in FIG. 2, the common supply flow path 211 of each color is connected to the pressure adjustment mechanism H of the high pressure side of the negative pressure control unit 230 of the corresponding color via the liquid supply unit 220. The common recovery flow path 212 of each color is connected to the pressure adjustment mechanism L of the low pressure side of the negative pressure control unit 230 of the corresponding color via the liquid supply unit 220. This negative pressure control unit 230 is configured to generate a pressure difference between the common supply flow path 211 and the common recovery flow path 212. As shown in FIG. 5, the common supply flow paths 211a to 211d and the common recovery flow paths 212a to 212d of each color are connected to the individual supply flow paths 213a and the individual recovery flow paths 213b via the communication port 61, respectively. The individual supply flow paths 213a and the individual recovery flow paths 213b are connected to the liquid paths in the ejection module 200 via the communication port 51, respectively. For this reason, in the liquid ejection head 3 of the present embodiment, a flow is generated for each color that flows in order from the common supply flow paths 211a to 211d through the individual supply flow path 213a, the recording element substrate 10, and the individual recovery flow path 213b to the common recovery flow paths 212a to 212d.

[0022] The fixed state of the flow path member 210 and the support member 81 of the liquid ejection head 3 of this embodiment will be described. FIG. 6(a) is an exploded perspective view of the flow path member 210 and the support member 81. FIG. 6(b) is a perspective view of the assembled state of the flow path member 210 and the support member 81. FIG. 7(a) is a schematic plan view of the flow path member 210 shown in FIG. 6(a). FIG. 7(b) is a schematic plan view of the support member 81 shown in FIG. 6(a). FIGS. 8(a) and 8(b) are schematic plan views showing a state in which the flow path member 210 shown in FIG. 6 is fixed to the support member 81. FIGS. 7(a), 7(b), 8(a), and 8(b) show a part of the configuration simplified for ease of understanding.

[0023] In this embodiment, seven fixing parts 214 and two positioning parts 215 are formed along the outer periphery of the flow path member 210. Each fixing part 214 has a screw through hole 216, 217 or a positioning elongated hole 218 formed therein. That is, two of the three fixing parts 214 located approximately in the center of the flow path member 210 in the longitudinal direction have a round screw through hole 216 formed therein. The remaining fixing part 214 has a positioning elongated hole 218 having a major axis in the short direction of the flow path member 210 formed therein. Four fixing parts 214 on both sides in the longitudinal direction of the flow path member 210 have a screw through hole 217 having a major axis in the longitudinal direction of the flow path member 210 formed therein. The positioning part 215 is formed on a side surface 210A located on the common supply flow path side in the short direction among the side surfaces extending in the longitudinal direction of the flow path member 210. The positioning portion 215 is located closer to the end in the longitudinal direction than the fixing portion 214 on both sides in the longitudinal direction of the flow path member 210. In this specification, the central portion in the longitudinal direction does not refer to only one point in the center, but refers to a region including the central point. In this specification, the side portion in the longitudinal direction does not refer to only the end in the longitudinal direction, but refers to a region on the end side of the central portion in the longitudinal direction.

[0024] Abutment portions 85 are formed on the support member 81 at positions facing the positioning portions 215 on both sides of the flow path member 210 in the longitudinal direction. A positioning pin 86 is formed on the support member 81 at a position corresponding to a positioning elongated hole 218 in the longitudinal center of the flow path member 210. Screw holes 87 are formed on the support member 81 at positions corresponding to the screw through holes 216 and 217 of the flow path member 210. The flow path member 210 and the support member 81 are fixed to each other by a screw 219 that penetrates the screw through holes 216 and 217 of the flow path member 210 and is screwed into the screw hole 87 of the support member 81. The screw through holes 216 and 217 and the positioning elongated hole 218 each have a dimension larger than the diameter of the screw 219, taking into account the dimensional tolerances of the flow path member 210 and the support member 81. As shown in FIG. 8(a), the flow path member 210 and the support member 81 may be fixed to each other with a distance (gap) d of, for example, 50 μm or less between the positioning portion 215 and the abutting portion 85. In this case, the relative positions of the flow path member 210 and the support member 81 in the short-side direction are determined with an accuracy of an error of 50 μm or less by the positioning portion 215 and the abutting portion 85. However, as shown in FIG. 8(b), the flow path member 210 and the support member 81 may be fixed to each other with the positioning portion 215 and the abutting portion 85 abutting each other. In addition, it is preferable that the positioning portion 215 is formed at a position closer to the end of the flow path member 210 in the longitudinal direction, because the influence of one-sided abutment of the flow path member 210 against the abutting portion 85 can be reduced and more suitable positioning can be achieved.

[0025] During the manufacture of the liquid ejection head of this embodiment, before the flow path member 210 and the support member 81 are fixed to each other, the positioning pin 86 of the support member 81 is inserted into the positioning elongated hole of the flow path member 210, thereby positioning the flow path member 210 in the longitudinal direction. However, the positioning pin 86 is movable inside the positioning elongated hole 218 in the long axis direction of the positioning elongated hole 218, i.e., in the lateral direction of the flow path member 210. Therefore, the flow path member 210 is movable in the lateral direction relative to the support member 81 within the range in which the positioning pin 86 is located in the positioning elongated hole. In this manner, the flow path member 210 is supported by the support member 81 so as to be movable in the lateral direction but immovable in the longitudinal direction.

[0026] When the abutting portion 85 of the support member 81 abuts against the positioning portion 215 of the flow path member 210 with the positioning pin 86 inserted into the positioning elongated hole of the flow path member 210, movement of the flow path member 210 in the short side direction relative to the support member 81 is restricted. Therefore, the flow path member 210 is positioned in the short side direction relative to the support member 81 because the positioning pin 86 is held inside the positioning elongated hole 218 and because the abutting portion 85 abuts against the positioning portion 215 and cannot move any closer.

[0027] Then, the screw 219 is passed through the elongated screw through holes 217 located on both sides of the flow path member 210 in the longitudinal direction and screwed into the screw hole 87 of the support member 81. The screw 219 and the elongated screw through hole 217 further ensure the positioning of the flow path member 210 in the short direction relative to the support member 81. However, the elongated screw through hole 217 and the screw 219 do not restrict the movement of the flow path member 210 in the longitudinal direction relative to the support member 81. Then, the screw 219 is passed through the elongated screw through hole 216 located in the center of the flow path member 210 in the longitudinal direction and screwed into the screw hole 87 of the support member 81. By passing the screw 219 through the screw through holes 216 and 217 and screwing into the screw hole 87 of the support member 81 in this way, the flow path member 210 is fixed while being positioned in the thickness direction relative to the support member 81. In this way, the flow path member 210 is fixed to the support member 81 with good positional accuracy, and warping of the flow path member 210 in the thickness direction is suppressed.

[0028] FIG. 9 is a schematic diagram showing a deformation state of the flow path member 210 along the longitudinal direction of the flow path member 210. FIG. 9 shows a simplified portion of the configuration for easy understanding. As shown in FIG. 9, the common supply flow paths 211 and the common recovery flow paths 212 of the respective colors are alternately arranged in the short side direction of the flow path member 210, and are formed parallel to each other along the longitudinal direction of the flow path member 210. Although not shown, the recording element substrate 10 has a heat generating portion that heats the liquid in the recording element substrate. The heat generating portion may be an energy generating element that generates thermal energy for ejecting the liquid in the recording element substrate (pressure chamber) from the ejection port, or may be a temperature adjusting element that adjusts the temperature of the liquid in the recording element substrate (pressure chamber). The heat generating portion may include both a temperature adjusting element and an energy generating element. The liquid flowing through the common recovery flow path 212 is a liquid that is recovered after being heated by the heat generating portion of the recording element substrate 10, and therefore has a higher temperature than the liquid flowing through the common supply flow path 211. Therefore, a temperature distribution occurs in the common supply flow path 211 and the common recovery flow path 212, and deformation of the flow path member 210 occurs as shown by arrows in Fig. 9. Specifically, the thermal expansion of the common recovery flow path 212 side, through which a relatively high-temperature liquid flows, in the flow path member 210 is larger than the thermal expansion of the common supply flow path 211 side, through which a relatively low-temperature liquid flows. Therefore, when the forces indicated by the arrows A, B, and B' in Fig. 9 act on the flow path member 210 to deform it, the positioning portion 215 and the abutting portion 85 formed on the side surface 210A located on the common supply flow path side in the short direction among the side surfaces extending in the longitudinal direction of the flow path member 210 approach each other. When the positioning portion 215 and the abutting portion 85 come into contact with each other, the flow path member 210 is prevented from being deformed further. A positioning portion 215 is formed on side 210A, which is located on the common supply flow path side in the short side direction among the side surfaces extending in the longitudinal direction of flow path member 210, so that the positioning portion 215 and the abutment portion 85 can effectively determine the position of the flow path member 210 in the short side direction.

[0029] In the comparative example shown in FIG. 10, the positions of the common supply flow passage 211 and the common recovery flow passage 212 are changed compared to the embodiment shown in FIG. 9. As a result, a positioning portion 215 is formed on a side surface 210B located on the common recovery flow passage side in the short side direction among the side surfaces extending in the longitudinal direction of the flow passage member 210, and an abutting portion 85 is formed at a position opposite to the positioning portion 215. In this case, forces indicated by arrows A, B, and B' act due to the difference in thermal expansion between the common recovery flow passage 212 side and the common supply flow passage 211 side of the flow passage member 210, and as shown typically by arrows in FIG. 10, the flow passage member 210 deforms in a manner opposite to the deformation shown in FIG. 9. That is, the flow passage member 210 deforms so that the interval d between the positioning portion 215 and the abutting portion 85 becomes larger. Therefore, the positioning portion 215 and the abutting portion 85 do not abut and do not contribute to the regulation of the short side position of the flow passage member 210. 9, it is preferable that, of the side surfaces extending in the longitudinal direction of the flow path member 210, a side surface 210A located on the common supply flow path side in the lateral direction is formed with positioning portions 215 at both longitudinal ends, and that abutment portions 85 are formed at positions opposite the positioning portions 215. With this configuration, the position of the flow path member 210 in the lateral direction can be well defined.

[0030] In this embodiment, as described above, the flow path member 210 has its longitudinal position determined relative to the support member 81 by the positioning elongated hole 218 and the positioning pin 86 at the longitudinal center. The flow path member 210 has its lateral position determined relative to the support member 81 by the positioning portion 215 and the abutment portion 85 at both longitudinal sides. Furthermore, the flow path member 210 is fixed at least at the longitudinal center by the screw 219 while its thickness direction position is determined relative to the support member 81. This keeps deformation of the flow path member 210 relative to the support member 81 small.

[0031] [Other embodiments] Fig. 11 is a cross-sectional view taken along the short side direction of a liquid ejection head according to another embodiment of the present invention. In the configuration shown in Figs. 5 and 9, the common supply flow paths 211a-211d and the common recovery flow paths 212a-212d for each color are alternately arranged in the short side direction of the flow path member 210. In contrast, in this embodiment, only one set of common supply flow path 211 and common recovery flow path 212 is arranged side by side in the short side direction of the flow path member 210. Similarly to the configuration shown in Fig. 5, the outermost flow path on the flexible wiring board (not shown) side (left side in Fig. 5) of the flow path member 210 is the common recovery flow path 212.

[0032] FIG. 12(a) is a schematic plan view of the flow path member 210 of this embodiment. FIG. 12(b) is a schematic plan view of the support member 81 of this embodiment. FIGS. 13(a), 13(b), and 13(c) are schematic plan views showing the fixed state of the flow path member 210 of this embodiment. FIGS. 12 and 13 show a part of the configuration simplified for easy understanding. In the configuration shown in FIG. 9, the positioning portion 215 is formed on the longitudinal end side of the fixing portion 214 on both longitudinal sides of the flow path member 210. In this embodiment, the positioning portion 215 is also formed on the side surface 210A (see FIG. 14) located on the common supply flow path 211 side in the short direction among the side surfaces extending in the longitudinal direction of the flow path member 210. In this embodiment, the positioning portion 215 is formed on the longitudinal center side of the fixing portion 214 on both longitudinal sides of the flow path member 210, as shown in FIG. 13(a). Then, the abutting portion 85 is formed at a position facing the positioning portion 215. As a result, as shown in FIG. 13(c), the longitudinal dimensions of the flow path member 210 and the support member 81 can be shortened, and the longitudinal dimensions of the liquid ejection head 3 can be reduced. This reduces the overall amount of deformation. As shown in FIG. 13(a), the flow path member 210 and the support member 81 may be fixed with a gap d between the positioning portion 215 and the abutting portion 85, for example, of 50 μm or less. However, as shown in FIGS. 13(b) and 13(c), the positioning portion 215 and the abutting portion 85 may abut against each other.

[0033] In this embodiment, the flow path member 210 is held at the center in the longitudinal direction by the positioning pin 86 of the support member 81 and the positioning elongated hole 218 of the flow path member 210 so as to be movable in the lateral direction relative to the support member 81 but immovable in the longitudinal direction. The position of the flow path member 210 in the lateral direction is determined by the positioning portion 215 and the abutment portion 85 on both sides in the longitudinal direction. The flow path member 210 is fixed at least at the center in the longitudinal direction by the screw 219 while the position in the thickness direction is determined relative to the support member 81. In this way, the flow path member 210 is fixed to the support member 81 with good positional accuracy, and warping of the flow path member 210 in the thickness direction is suppressed.

[0034] FIG. 14 is a schematic diagram along the longitudinal direction of the flow path member 210, showing the deformation state of the flow path member 210. FIG. 14 shows a simplified part of the configuration for easy understanding. As shown in FIGS. 11 and 14, the flow path member 210 is formed with a set of a common supply flow path 211 and a common recovery flow path 212 extending in the longitudinal direction of the flow path member 210, so as to be aligned with each other in the lateral direction of the flow path member 210. As described above, the liquid flowing through the common recovery flow path 212 is hotter than the liquid flowing through the common supply flow path 211. A temperature distribution occurs in the common supply flow path 211 and the common recovery flow path 212, and deformation occurs in the flow path member 210 as shown diagrammatically by the arrows in FIG. 14. That is, since the thermal expansion of the common recovery flow path 212 side of the flow path member 210 is larger than the thermal expansion of the common supply flow path 211 side, forces indicated by the arrows A, B, B', C, and C' in FIG. 14 act on the flow path member 210, causing deformation. This deformation is in the same direction as the deformation direction in the example shown in FIG. 9, and the temperature distribution is large because the number of common supply flow paths 211 and common recovery flow paths 212 in the flow path member 210 is small. Thus, the larger the temperature difference in the short-side direction of the flow path member 210 is, and the longer the flow path member 210 is, the more the flow path member 210 tends to deform. In contrast, in this embodiment, the flow path member 210 is prevented from deforming in the short-side direction against the force of arrow A in FIG. 14 by defining the position of the flow path member 210 in the fixing portion 214 at the center of the long-side direction of the flow path member 210. In addition, the positioning portion 215 abuts against the abutting portion 85, thereby preventing the deformation of the flow path member 210 in the short-side direction against the forces of arrows C and C'. Note that, as shown in FIGS. 13(b) and 13(c), the abutting portion 85 is abutted against the positioning portion 215 from the beginning, so that the deformation of the flow path member 210 can be prevented more effectively. Furthermore, deformation of the flow path member 210 can be suppressed by fixing the abutment portion 85 to the positioning portion 215 by a method such as adhesion.

[0035] As described above, in the present invention, the flow path member 210 has a longitudinal position determined relative to the support member 81 by the positioning slot 218 and the positioning pin 86 at the longitudinal center. The flow path member 210 has a lateral position determined relative to the support member 81 by the positioning portion 215 and the abutting portion 85 at both longitudinal sides. Furthermore, the flow path member 210 is fixed at least at the longitudinal center while its thickness position is determined relative to the support member 81 by the screw 219. That is, the flow path member 210 is not positioned in all directions at the same location, but the longitudinal position, the lateral position, and the thickness position are determined at different locations. Therefore, the flow path member 210 can be positioned in each direction at each location with high accuracy and without distortion. In particular, the flow path member 210 is positioned in the longitudinal center, so that deformation in the longitudinal direction can be efficiently suppressed. In addition, the positioning of the flow path member 210 in the short-side direction is performed on both longitudinal sides of the side surface located on the common supply flow path side, which has a relatively low temperature in the short-side direction. This makes it possible to restrict deformation of the flow path member 210 in the short-side direction at a portion where deformation in the short-side direction is likely to occur, and deformation in the short-side direction can be efficiently suppressed. If the positioning of the flow path member 210 in the thickness direction is performed at a plurality of locations on the outer periphery of the flow path member, deformation in the thickness direction can be suppressed more effectively. In this way, when deformation in the short-side direction of the flow path member 210 occurs due to temperature distribution in the common supply flow path 211 and the common recovery flow path 212, deformation in each direction of the flow path member 210 can be suppressed. As a result, it is possible to provide a liquid ejection head capable of ejecting liquid with high precision and quality. [Explanation of symbols]

[0036] 10. Recording element board 10a outlet 81 Support member 210 Flow path components 210A Side located on the common supply channel side 211 Common supply channel 212 Common recovery channel

Claims

1. a recording element substrate having an ejection port for ejecting liquid; a common supply flow path for supplying liquid to the recording element substrate, and a common recovery flow path for recovering liquid from the recording element substrate and through which a liquid having a higher temperature than the liquid flowing through the common supply flow path flows, the common supply flow path extending along a longitudinal direction of the flow path member and being aligned with each other in a lateral direction of the flow path member; a support member for supporting the flow path member, the flow path member has a plurality of fixing portions fixed to the support member and a positioning portion that is positioned with respect to the support member, Among the plurality of fixing portions, a fixing portion located at a center portion in the longitudinal direction is a fixing portion provided on a side surface of the flow path member that is located on the common recovery flow path side in the short direction of the flow path member, the side surface having a long axis in the short direction of the flow path member and that defines a position in the long direction with respect to the support member; a fixing portion having a screw through hole that fixes the support member while determining a position in a thickness direction of the support member, Among the plurality of fixing portions, fixing portions located on both sides in the longitudinal direction have a screw through hole having an elongated hole shape with a long axis in the longitudinal direction, the positioning portion is provided on a side surface of the flow path member that is located on the common supply flow path side in a short side direction of the flow path member, among side surfaces extending in the longitudinal direction of the flow path member, and is located on both side portions of the flow path member in the longitudinal direction; the support member has a positioning pin arranged at a position facing the positioning elongated hole and a butting portion facing the positioning portion in the short side direction, the positioning pin is inserted into the positioning elongated hole, and holds the flow path member so as to be movable relative to the support member in the short side direction within a range in which the positioning pin is positioned within the positioning elongated hole; The flow path member is fixed to the support member by a screw that is screwed into the support member through the screw through hole.

2. A plurality of the recording element substrates are included, 2. The liquid ejection head according to claim 1, wherein the flow path member supports a plurality of the recording element substrates, and has a plurality of individual supply flow paths connected to each of the recording element substrates, and a plurality of individual recovery flow paths connected to each of the recording element substrates, and the common supply flow path is connected to a plurality of the individual supply flow paths, and the common recovery flow path is connected to a plurality of the individual recovery flow paths.

3. the recording element substrate has an ejection port array in which a plurality of the ejection ports are arranged, 3. The liquid ejection head according to claim 2, wherein the plurality of recording element substrates are arranged on the flow path member in a state where the ejection ports of the recording element substrates at least partially overlap each other in the ejection port array direction.

4. A liquid ejection head described in any one of claims 1 to 3, wherein the flow path member has only one set of the common supply flow path and the common recovery flow path.

5. The liquid ejection head according to claim 1 , wherein the positioning portion is formed closer to a center portion in the longitudinal direction than the fixing portions located on both sides of the flow path member in the longitudinal direction.

6. A liquid ejection head described in any one of claims 1 to 5, wherein the distance between the positioning portion and the abutment portion is 50 μm or less.

7. The liquid ejection head according to claim 1 , wherein a plurality of the fixing portions are formed and aligned along an outer periphery of the flow path member.

8. The liquid ejection head according to claim 1 , wherein the flow path member is constituted by a plurality of plate-like members laminated in a thickness direction.

9. The liquid ejection head according to claim 1 , wherein a linear expansion coefficient of the material of the support member is equal to or lower than a linear expansion coefficient of the material of the flow path member.

10. The liquid ejection head according to claim 1 , wherein the recording element substrate has a heat generating portion.

11. 11. The liquid ejection head according to claim 10, wherein the heat generating portion is an energy generating element that generates thermal energy for ejecting the liquid in the recording element substrate from the ejection port.

12. The liquid ejection head according to claim 10 , wherein the heat generating portion is a temperature adjusting element that adjusts the temperature of the liquid in the recording element substrate.

13. The liquid ejection head according to claim 10 , wherein the heat generating portion includes a temperature adjusting element that adjusts a temperature of the liquid in the recording element substrate, and an energy generating element that generates thermal energy for ejecting the liquid in the recording element substrate from the ejection port.

14. 14. The liquid ejection head according to claim 1, which is a line-type liquid ejection head having a recording width corresponding to a recording width of a recording medium.

15. A method for manufacturing a liquid ejection head, comprising: a flow path member having a recording element substrate having an ejection port for ejecting liquid; a common supply flow path for supplying liquid to the recording element substrate; and a common recovery flow path for recovering liquid from within the recording element substrate and through which a liquid having a higher temperature than that of the liquid flowing through the common supply flow path flows, the flow path member extending along a longitudinal direction of the flow path member and being aligned with each other in a lateral direction of the flow path member; and a support member for supporting the flow path member, a positioning pin provided on the support member at a central portion of the longitudinal direction of the flow path member, the positioning pin being provided on the support member and having a long axis in the short direction and provided in a fixing portion located at the central portion of the longitudinal direction, to determine a position in the longitudinal direction while allowing the flow path member to move in the short direction relative to the support member within a range in which the positioning pin is located within the positioning long hole, and then, with the short direction position being determined by abutment portions provided on the support member on one of the longitudinally extending sides that is located on the common supply flow path side in the short direction, a screw is screwed into the support member through a long hole-shaped screw through hole having a long axis in the longitudinal direction and provided in a fixing portion located on both sides in the longitudinal direction, thereby fixing the flow path member at least in the central portion of the longitudinal direction while determining its position in the thickness direction relative to the support member.

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