Liquid discharge head and liquid discharge device
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2022-12-27
- Publication Date
- 2026-05-22
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]
[0002] Patent Document 1 discloses a recording device in which a heating element for heating ink is used as a recording element in a recording element substrate, and the ink is heated by the heating element to generate bubbles in the ink, and the ink is discharged from the discharge port by the bubbling pressure. Patent Document 1 further discloses that the ink in the recording element substrate is heated by a sub-heater or a heating element to adjust the ink to a set temperature, thereby reducing the variation in the amount of ink discharged from the discharge port caused by the ink temperature. In other words, the temperature of the supplied ink is raised by the sub-heater or the heating element to suppress the variation in the amount of ink discharged. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent Publication No. 2022-073137 Summary of the Invention [Problem to be solved by the invention]
[0004] In the technology disclosed in Patent Document 1, the ink supplied to the recording element substrate is relatively cooler than the ink inside the recording element substrate. Therefore, the closer the ink inside the recording element substrate is to the ink supply portion, the lower its temperature becomes. As a result, there is a risk of variation occurring between the amount of ink discharged from the discharge ports close to the ink supply portion and the amount of ink discharged from the discharge ports far from the ink supply portion.
[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a technique for suppressing variations in the amount of liquid ejected that are caused by the temperature of the liquid. [Means for solving the problem]
[0006] In order to achieve the above-mentioned object, one embodiment of a liquid ejection head according to the present invention comprises a substrate having a plurality of ejection ports capable of ejecting liquid, a supply port for supplying liquid to the plurality of ejection ports, a recovery port for recovering liquid not ejected from the plurality of ejection ports, and an energy generating element capable of generating energy for ejecting liquid from the ejection ports; a flow path member arranged and disposed on the substrate, in which a supply flow path for supplying liquid to the supply port is formed on one side of the substrate in a first direction intersecting the arrangement direction of the substrate, and a recovery flow path for recovering liquid from the recovery port is formed on the other side of the first direction; and a heating means for heating an ejection region in the substrate in which the ejection ports are formed, wherein the substrate is characterized in that, on both sides of the first direction of the ejection region, the recovery flow path is disposed on the side where the distance between the ejection region and an edge of the substrate in the first direction is relatively long, and the supply flow path is disposed on the side where the distance between the ejection region and an edge of the substrate in the first direction is relatively long. Effect of the Invention
[0007] According to the present invention, it is possible to suppress variations in the amount of liquid ejected that are caused by the temperature of the liquid. [Brief description of the drawings]
[0008] [Figure 1] Schematic diagram of a recording apparatus which is a liquid ejection apparatus. [Diagram 2] A block diagram showing the configuration of a control system of a printing apparatus. [Diagram 3] Circulation system schematic diagram [Figure 4] A perspective view of a recording head [Diagram 5] Exploded view of the recording head [Figure 6] Schematic diagram of the discharge module [Figure 7] Schematic diagram of a flow path member and a support member [Figure 8]Schematic diagram of the recording element substrate [Figure 9] Cross-sectional view of a recording element substrate [Figure 10] FIG. 1 is a diagram for explaining the connection relationship between the flow passages of the recording element substrate and the flow passages of the flow passage member; [Figure 11] FIG. 13 is a diagram showing a recording element substrate disposed on the bottom surface of a flow path member. [Figure 12] FIG. 13 is a diagram showing an example of the arrangement position of a recording element substrate on the bottom surface of a flow path member. [Figure 13] FIG. 13 is a diagram showing a modified example of a recording head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] An example of a liquid ejection head and a liquid ejection device according to the present invention will be described in detail below with reference to the accompanying drawings. Note that the following embodiment does not limit the present invention, and not all of the combinations of features described in the present embodiment are essential to the solution of the present invention. Furthermore, the positions, shapes, and the like of the components described in the present embodiment are merely examples, and are not intended to limit the scope of the present invention to only those.
[0010] (Configuration of recording device) First, the configuration of a liquid ejection device equipped with a liquid ejection head according to this embodiment will be described. In this specification, an inkjet recording device (hereinafter, simply referred to as a "recording device") that ejects ink by an inkjet method and records on a recording medium will be described as an example of a liquid ejection device. FIG. 1 is a schematic diagram of a recording device. Note that the recording device to which this embodiment can be applied is not limited to the recording device shown in FIG. 1. That is, this embodiment can be applied to various devices equipped with various known recording functions that eject ink and record. Note that in this specification, directions are indicated by the X direction, Y direction, and Z direction, which are orthogonal to each other. Each direction is from one side to the other.
[0011] The recording device 10 shown in FIG. 1 includes a transport unit 12 that transports a recording medium M, and a recording unit 14 that ejects ink onto the recording medium M transported by the transport unit 12 to perform recording. The transport unit 12 is configured to transport the recording medium M in the X direction by, for example, placing the recording medium M on an endlessly stretched belt and rotating the belt. Note that the configuration of the transport unit 12 of the recording device 10 is not limited to the above configuration, and various known techniques can be applied. Also, the recording medium M is not limited to cut paper as shown in FIG. 1, but may be roll paper, or may be a film other than recording paper.
[0012] The recording unit 14 includes a plurality of recording heads 16. In this embodiment, the recording head 16 includes a recording head 16a that ejects black (Bk) ink, a recording head 16b that ejects cyan (C) ink, a recording head 16c that ejects magenta (M) ink, and a recording head 16d that ejects yellow (Y) ink. The four recording heads 16 extend in a Y direction intersecting the X direction (orthogonal in this embodiment) and are arranged in parallel along the X direction. In each recording head 16, a surface facing the recording medium M transported by the transport unit 12 is provided with a plurality of ejection port rows formed by arranging a plurality of ejection ports for ejecting ink in the Y direction. The type and number of inks ejected from the recording head 16 are not limited to the above-mentioned type and number of inks. In addition, the recording head 16 is not limited to ejecting only ink, and may be configured to be capable of ejecting various liquids such as a processing liquid that performs a predetermined process on the ink ejected on the recording medium M.
[0013] (Configuration of the control system of the recording device) Next, a description will be given of the configuration of the control system of the recording apparatus 10. FIG 2 is a block diagram showing the configuration of the control system of the recording apparatus 10.
[0014] The overall operation of the recording device 10 is controlled by a control unit 200. The recording device 10 includes a control unit 200, a ROM 202, and a RAM 204. The control unit 200 is composed of, for example, a CPU, and controls the operation of each component in the recording device 10 based on various programs. The ROM 202 functions as a memory that stores various control programs and image data processing programs executed by the control unit 200. The RAM 204 is a memory that temporarily stores various data used to control the recording device 10, and also functions as a work area used by the control unit 200 when executing various processes. The control unit 200 is also connected to an external device such as a host device 206.
[0015] The control unit 200 is connected to a transport motor driver 208, and controls the transport amount and transport speed of the recording medium M in the transport unit 12 via the transport motor driver 208. The control unit 200 is also connected to a printhead driver 210, and controls the ejection of ink from each printhead 16 via the printhead driver 210. The control unit 200 is also connected to a drive driver 212, and controls the circulation of ink in a circulation system 300 (described later) via the drive driver 212. In FIG. 2, for ease of understanding, the drivers that control each component used to control the circulation of ink in the circulation system 300 are shown as one driver. The control unit 200 is also connected to a temperature sensor 214 and a sub-heater 216 provided on each printing element substrate 400 (described later) in the printhead 16. The control unit 200 controls the driving of the sub-heater 216 based on the detection result from the temperature sensor 214.
[0016] The control unit 200 performs image processing on the image data output from the host device 206, for example, according to a processing program and parameters stored in the ROM 202, and generates recording data for ejecting ink from the recording head 16. The control unit 200 then drives the recording head 16 based on the generated recording data, causing it to eject ink at a predetermined frequency. When ejecting ink from the recording head 16, the control unit 200 drives the transport unit 12 to transport the recording medium M at a speed corresponding to the drive frequency. As a result, an image corresponding to the image data input from the host device 206 is recorded on the recording medium M.
[0017] Further, although details will be described later, a plurality of recording element substrates 400 are arranged in each recording head 16. Each recording element substrate 400 is provided with a plurality of temperature sensors 214 for detecting the temperature of the recording element substrate 400 and a plurality of sub-heaters 216 for heating the recording element substrate 400. In FIG. 2, for ease of understanding, the plurality of temperature sensors 214 and the plurality of sub-heaters 216 are shown collectively as one each. Therefore, the control unit 200 drives the sub-heater 216 based on the detection result of the temperature sensor 214 to maintain the temperature of each recording element substrate 400 within a set range.
[0018] (Circulation System) The recording apparatus 10 is provided with a circulation system that circulates ink in a circulation path including the recording head 16 in order to suppress thickening of ink in the ejection ports that are not performing printing and in the pressure chambers corresponding to the ejection ports among the ejection ports provided in the recording head 16. FIG. 3 is a diagram that shows a schematic diagram of a circulation system 300 in the recording apparatus 10. Note that the circulation system 300 shown in FIG. 3 is provided for each recording head 16. That is, in this embodiment, the recording apparatus 10 is provided with a circulation system 300 for each of the four recording heads 16.
[0019] The circulation system 300 includes a buffer tank 302 that stores the corresponding ink, and an ejection unit 304 that can eject the ink. The circulation system 300 also includes a supply unit 306 that supplies the ink from the buffer tank 302 to the ejection unit 304 and transfers the ink collected from the ejection unit 304 to the buffer tank. In this embodiment, a configuration including the ejection unit 304 and the supply unit 306 is provided in the print head 16, and the buffer tank 302 and a pump for circulating the ink are disposed at predetermined positions in the printing apparatus 10.
[0020] The buffer tank 302 is provided with an air communication port (not shown) that communicates the inside of the tank with the outside of the tank. This allows the buffer tank 302 to discharge air bubbles in the ink stored inside the tank to the outside. The buffer tank 302 is also connected to a main tank 308 that stores the corresponding ink, and ink from the main tank 308 is supplied to the buffer tank 302 by driving a refill pump 310. For example, when ink is consumed by ejection (discharge) of ink from the print head 16, such as during printing or suction recovery, the refill pump 310 is driven to supply the consumed amount of ink from the main tank 308 to the buffer tank 302.
[0021] The buffer tank 302 is connected to a liquid connection part 314a of the supply unit 306 by a supply path 312. A first circulation pump 316 is provided in this supply path 312, and ink in the buffer tank 302 is supplied to the supply unit 306 via the supply path 312 by driving the first circulation pump 316. A negative pressure control unit 318 is provided in the supply unit 306, and the ink supplied to the supply unit 306 is transferred to the negative pressure control unit 318 via a filter 320. The ink transferred to the negative pressure control unit 318 is then transferred to the ejection unit 304.
[0022] The negative pressure control unit 318 has a function of operating to maintain the pressure downstream of the negative pressure control unit 318, i.e., on the ejection unit 304 side, at a preset pressure even when the ink flow rate in the circulation system fluctuates due to a difference in the duty for recording. The negative pressure control unit 318 has two negative pressure adjustment units set with different control pressures. Of the two negative pressure adjustment units, the negative pressure adjustment unit 318a set to a relatively high pressure transfers ink to a common supply flow path 324 of the ejection unit 304 via a supply path 322. The negative pressure adjustment unit 318b set to a relatively low pressure transfers ink to a common recovery flow path 328 of the ejection unit 304 via a supply path 326.
[0023] The ejection unit 304 is formed with a common supply flow path 324, a common recovery flow path 328, and individual flow paths 330. The common supply flow path 324 is a flow path through which ink to be supplied to each recording element substrate 400 (described later) flows, and the common recovery flow path 328 is a flow path through which ink flowing out (recovered) from each recording element substrate 400 flows. The individual flow path 330 is composed of an individual supply flow path 330a and an individual recovery flow path 330b. The individual supply flow path 330a is a flow path that guides ink in the common supply flow path 324 to the recording element substrate 400, and the individual recovery flow path 330b is a flow path that guides ink flowing out from the recording element substrate 400 to the common recovery flow path 328.
[0024] Moreover, the common recovery flow path 328 of the ejection unit 304 is connected to the supply unit 306 via a recovery path 331, and the supply unit 306 is connected to the buffer tank 302 via a recovery path 332. The recovery path 332 is connected to a liquid connection portion 314b of the supply unit 306. A second circulation pump 334 is provided in the recovery path 332, and by driving the second circulation pump 334, ink is sucked from the common recovery flow path 328 and sent (recovered) to the buffer tank 302 via the recovery path 332.
[0025] The recording element substrate 400 is in communication with the common supply flow path 324 and the common recovery flow path 328 by the individual flow paths 330. Therefore, a part of the ink supplied to the ejection unit 304 via the supply unit 306 by the first circulation pump 316 passes through the internal flow path of the recording element substrate 400 from the common supply flow path 324 and flows into the common recovery flow path 328. This is because ink is transferred from the negative pressure adjustment unit 318a to the common supply flow path 324, and ink is transferred from the negative pressure adjustment unit 318b to the common recovery flow path 328, causing a pressure difference between the two flow paths. Also, this is because ink is sucked (recovered) only from the common recovery flow path 328 by the second circulation pump 334.
[0026] In this manner, in the discharge unit 304, there occurs a flow of ink passing through the common recovery channel 328, and a flow of ink from the common supply channel 324 through each recording element substrate 400 toward the common recovery channel 328. Therefore, heat generated in each recording element substrate 400 (heat from the sub-heater 216 and the heating element 914) is discharged to the outside of the recording element substrate 400 by the flow of ink from the common supply channel 324 to the common recovery channel 328.
[0027] In the recording device 10, since the circulation system 300 is provided, when recording is performed by the recording head 16, ink flows also in the ejection ports that do not eject ink and in the pressure chambers corresponding to the ejection ports. This makes it possible to suppress the increase in viscosity of the ink in the ejection ports and pressure chambers. In addition, since the thickened ink and foreign matter in the ink can be discharged to the common recovery flow path 328, the recording head 16 can perform high-speed, high-quality recording.
[0028] (Recording head configuration) <Overall configuration of the recording head> Next, the recording head 16 will be described. First, the overall configuration of the recording head 16 will be described. FIG. 4 is a schematic diagram of the recording head, where (a) is a perspective view seen from one side (upper side) in the Z direction, and (b) is a perspective view seen from the other side (lower side) in the Z direction. FIG. 5 is an exploded perspective view of the recording head 16. For ease of understanding, the directions used in the following description of the recording head refer to the directions when the recording head 16 is attached to the recording device 10.
[0029] The recording head 16 is formed to extend in the Y direction (see FIG. 4(a)). When the recording head 16 is mounted on the recording device 10, a plurality of recording element substrates 400 capable of ejecting ink are linearly arranged along the Y direction on the surface facing the recording medium M transported by the transport unit 12 (see FIG. 4(b)). The recording head 16 is a so-called line-type recording head.
[0030] The printhead 16 includes a signal input terminal 406 and a power supply terminal 408 electrically connected to the print element substrate 400 via a flexible wiring substrate 402 and an electric wiring substrate 404. The signal input terminal 406 and the power supply terminal 408 are electrically connected to the control unit 200 of the printing apparatus 10, and supply the print element substrate 400 with an ejection drive signal and electric power required for ejection, respectively. By consolidating the wiring using an electric circuit in the electric wiring substrate 404, the number of signal input terminals 406 and power supply terminals 408 can be made smaller than the number of print element substrates 400. This reduces the number of electrical connections that need to be removed when attaching or detaching the printhead 16 to or from the printing apparatus 10.
[0031] The recording head 16 is connected to the supply path 312 and the recovery path 332 by liquid connectors 314 (indicated as 314a and 314b in FIG. 3) provided near both ends in the Y direction. As a result, ink is supplied to the recording head 16 from the supply path 312, and ink is recovered in the recovery path 332.
[0032] In the recording head 16, the ejection unit 304, the supply unit 306, and the electric wiring board 404 are assembled in a housing 500 (see FIG. 5). The supply unit 306 is provided with a liquid connection part 314, and a filter 320 (see FIG. 3) is provided inside the supply unit 306 for removing foreign matter in the ink supplied from the supply path 312 via the liquid connection part 314. The ink that has passed through the filter 320 is supplied to a negative pressure control unit 318 connected to the supply unit 306.
[0033] The negative pressure control unit 318 is a unit consisting of a pressure adjustment valve, and the valves and spring members provided therein act to greatly attenuate pressure loss changes outside the recording head 16 in the circulation system 300 that occur with fluctuations in the ink flow rate. This makes it possible to stabilize negative pressure changes in the ejection units 304 downstream of the negative pressure control unit 318 within a certain range. In addition, the negative pressure control unit 318 has two pressure adjustment valves (negative pressure adjustment parts 318a and 318b) built in, each set to a different control pressure. Of the two pressure adjustment valves, the high pressure side is connected to the common supply flow path 324 of the ejection units 304, and the low pressure side is connected to the common recovery flow path 328 of the ejection units 304.
[0034] The housing 500 includes a discharge unit support portion 502 that supports the discharge unit 304, and an electric wiring board support portion 504 that supports the electric wiring board 404. The rigidity of the recording head 16 is ensured by the housing 500. The electric wiring board support portion 504 is fixed to the discharge unit support portion 502 by screwing. The discharge unit support portion 502 is provided with openings 508 and 510 into which a joint rubber 506 is inserted. The ink supplied from the supply unit 306 is guided to a flow path member 512 (described later) that constitutes the discharge unit 304 via the joint rubber 506. In other words, the joint rubber 506 corresponds to the supply paths 322 and 326 and the recovery path 331 in FIG. 3.
[0035] The discharge unit 304 includes a flow path member 512 including a first flow path member 514 and a second flow path member 516, a discharge module 518 including a recording element substrate 400, and a cover member 520 that protects the outer peripheral portion of the recording element substrate 400. As described below, the discharge module 518 includes the recording element substrate 400 and a flexible wiring substrate 402. In the discharge module 518, the recording element substrate 400 is bonded to a bonding surface (bottom surface) 514a of the first flow path member 514 by an adhesive, and an end of the flexible wiring substrate 402 is electrically connected to a connection terminal 404a of the electrical wiring substrate 404.
[0036] The flow path member 512 is configured by laminating a first flow path member 514 and a second flow path member 516. The flow path member 512 has a flow path configuration that distributes ink supplied from the supply unit 306 to each ejection module 518 and returns ink returned from each ejection module 518 to the supply unit 306. The flow path member 512 is fixed to the ejection unit support part 502 by screwing.
[0037] <Configuration of the discharge module> Next, a description will be given of the discharge module 518. Figure 6 is a schematic diagram of the discharge module 518, where (a) is a perspective view of the discharge module 518, and (b) is an exploded view of the discharge module 518.
[0038] The ejection module 518 includes a recording element substrate 400 for ejecting ink, a support member 600 that supports the recording element substrate 400, and a flexible wiring substrate 402 that is connected to the recording element substrate 400 on the support member 600. The support member 600 has liquid communication ports 602 that extend substantially in the X direction and are arranged in the Y direction (see FIG. 6(b)). The number of liquid communication ports 602 provided in the support member 600 corresponds to, for example, the number of communication ports 700 (described later) provided in the flow path member 512. That is, the support member 600 and the recording element substrate 400 are joined in such a manner that each of the liquid communication ports 602 communicates with a corresponding communication port 700 of the flow path member 512.
[0039] The support member 600 is a support body that supports the recording element substrate 400, and is also a flow path member that fluidly connects the recording element substrate 400 and the flow path member 512. For this reason, it is preferable that the support member 600 has a high degree of flatness and can be joined to the recording element substrate 400 with high reliability. As the material, for example, alumina or a resin material is preferable.
[0040] In the recording element substrate 400 supported by the support member 600, a terminal 604 provided on one long side extending substantially in the Y direction and a terminal 606 provided on one end of the flexible wiring substrate 402 are electrically connected by wire bonding. The wire-bonded portion is covered and sealed with a sealing material (not shown). A terminal 608 provided on the other end of the flexible wiring substrate 402 is electrically connected to a connection terminal 404a of the electrical wiring substrate 404.
[0041] <Configuration of flow path components> Next, the flow path member 512 will be described in detail. FIG. 7 is a diagram for explaining the configuration of the flow path member 512 and the support member 600 joined to the flow path member 512. FIG. 7(a) is a diagram showing the support member 600 joined to the flow path member 512, and FIG. 7(b) is a diagram showing the joining surface 514a of the first flow path member 514. FIG. 7(c) is a cross-sectional view of the first flow path member 514 shown in FIG. 5 taken along line VIIc-VIIc, and FIG. 7(d) is a diagram showing the second flow path member 516. FIGS. 7(a) to (c) are views seen from one side (lower side) in the Z direction, and FIG. 7(d) is a view seen from the other side (upper side) in the Z direction.
[0042] On the bonding surface 514a of the first flow path member 514, arrangement positions P at which one support member 600 can be arranged are arranged side by side along the Y direction. At each arrangement position P, the support member 600 to which the recording element substrate 400 is joined is arranged in the ejection module 518. That is, at the arrangement position P, the recording element substrate 400 is located via the support member 600. With this configuration, by adjusting the number of ejection modules 518 arranged, recording heads 16 of various sizes in the Y direction can be produced.
[0043] 7A, the support member 600 is formed with a plurality of liquid communication ports 602, which are elongated holes penetrating the support member 600 in the Z direction and extending substantially in the X direction, along the Y direction. In this embodiment, seven liquid communication ports 602, the number of which corresponds to the communication ports 700 formed at each arrangement position P of the flow path member 512, are provided in the support member 600. The support member 600 connects, via the liquid communication ports 602, a flow path provided in the recording element substrate 400 arranged on the support member 600 and the communication ports 700 of the first flow path member 514 so that ink can be transported between them. In other words, the first flow path member 514 and the recording element substrate 400 are fluidically connected via the support member 600.
[0044] A plurality of communication ports 700 are formed at each arrangement position P of the first flow path member 514. The number of communication ports 700 corresponds to the number of opening rows Oc provided in a cover plate 908 (described later) of the recording element substrate 400, and seven communication ports 700 are formed in this embodiment. At each arrangement position P, three communication ports 700 are formed side by side in the approximately Y direction on one side in the X direction (the lower side in FIG. 7(b)), and the three communication ports 700 are connected to a common recovery flow path 328 (see FIG. 7(c)) formed in the first flow path member 514. Hereinafter, the communication port 700 communicating with the common recovery flow path 328 will be appropriately referred to as a communication port 700c. Furthermore, at each arrangement position P, four communication ports 700 are formed aligned approximately in the Y direction on the other side in the X direction (upper side in FIG. 7(b)), and the four communication ports 700 are connected to a common supply flow path 324 (see FIG. 7(c)) formed in the first flow path member 514. Hereinafter, the communication port 700 communicating with the common supply flow path 324 will be appropriately referred to as a communication port 700s. The communication ports 700s and the communication ports 700c are arranged so as to be alternately positioned in the Y direction.
[0045] As described above, each communication port 700 connected to the common supply flow path 324 or the common recovery flow path 328 is fluidly connected to the flow path of the recording element substrate 400 via the liquid communication port 602. Therefore, the flow path provided in the recording element substrate 400 is connected to the common supply flow path 324 and the common recovery flow path 328 via the liquid communication port 602 and the communication port 700. In this way, the liquid communication port 602 and the communication port 700 constitute a part of the individual supply flow path 330a and the individual recovery flow path 330b shown in FIG.
[0046] The first flow path member 514 has a common supply flow path 324 and a common recovery flow path 328 formed therein (see FIG. 7(c)). When the first flow path member 514 and the second flow path member 516 are joined together, a common communication port 702a formed near the end of the second flow path member 516 on the other side in the Y direction is located near the end of the common supply flow path 324 on the other side in the Y direction (the right side in FIG. 7). Meanwhile, a common communication port 702b formed near the end of the second flow path member 516 on the other side in the Y direction is located near the end of the common recovery flow path 328 on the other side in the Y direction. Also, a common communication port 702c formed near the end of the second flow path member 516 on one side in the Y direction (the left side in FIG. 7) is located near the end of the common recovery flow path 328 on one side in the Y direction. The common communication port 702a is connected to the supply path 322, the common communication port 702b is connected to the supply path 326, and the common communication port 702c is connected to a flow path that communicates with the recovery path 332 via the supply unit 306 (see FIG. 3).
[0047] <Configuration of the recording element substrate> Next, the recording element substrate 400 will be described. FIGS. 8 and 9 are diagrams for explaining the configuration of the recording element substrate 400. FIG. 8(a) is a diagram showing the surface of the recording element substrate 400 on which the ejection ports are formed. FIG. 8(b) is an enlarged view of the inside of the frame VIIIb in FIG. 8(a). FIG. 8(c) is a diagram showing a cover plate 908 constituting the recording element substrate 400. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8(a). In FIG. 8(a), in order to facilitate understanding, the liquid supply path, the liquid recovery path, and the openings provided in the recording element substrate 400 are shown in a see-through state.
[0048] As shown in FIG. 9, the recording element substrate 400 has an ejection port forming member 906 that forms ejection ports 904 formed on one surface of a substrate 902, and a cover plate 908 bonded to the other surface of the substrate 902. The substrate 902 is made of silicon (Si). The ejection port forming member 906 is formed by laminating a photosensitive resin on one surface of the substrate 902. The ejection port forming member 906 has a plurality of ejection ports 904 arranged along the Y direction to form an ejection port row, and a plurality of these ejection port rows are arranged in parallel in the X direction (see FIG. 8(b) and FIG. 9). The ejection port forming member 906 has pressure chambers 910 formed at positions corresponding to the respective ejection ports 904, and each pressure chamber 910 is partitioned by a partition wall 802 (see FIG. 8(b)).
[0049] In the cover plate 908, an aperture row Oc in which a plurality of apertures 820 are arranged at an incline with respect to the X direction is arranged in parallel along the Y direction (see FIGS. 8(a) and 8(c)). The inclination angle of each aperture row Oc corresponds to the inclination angle of the liquid communication port 602 with which each aperture 820 communicates when the recording element substrate 400 is joined to the support member 600. In adjacent aperture rows Oc, the apertures 820 are formed shifted by a predetermined amount in the X direction. It is preferable that the cover plate 908 has sufficient corrosion resistance against ink, and the apertures 820 are required to have a high degree of accuracy in the aperture shape and the aperture position. For this reason, it is preferable that the cover plate 908 is formed using a photosensitive resin material or a silicon plate, and the apertures 820 are formed by a photolithography process.
[0050] Heating elements 914 are provided as recording elements (energy generating elements) capable of generating energy for ejecting liquid from the ejection ports, within each pressure chamber 910 on one surface of the substrate 902, at positions corresponding to each ejection port 904. Furthermore, liquid supply paths 916 and liquid recovery paths 918 are formed along the arrangement direction of the ejection port arrays at positions corresponding to each ejection port array. Specifically, the liquid supply path 916 is provided along each ejection port array on one side of the ejection port array in the X direction, and the liquid recovery path 918 is provided on the other side of the ejection port array in the X direction.
[0051] The liquid supply path 916 is connected to a pressure chamber 910 formed by the ejection port forming member 906 on one side of the substrate 902 via a supply port 922, and the liquid recovery path 918 is connected to the pressure chamber 910 on one side of the substrate 902 via a recovery port 924. The liquid supply path 916 and the liquid recovery path 918 communicate with the openings 820 when the cover plate 908 is bonded to the substrate 902. In this embodiment, the liquid supply path 916 communicates with the openings 820 in the odd-numbered opening rows Oc in the Y direction of the cover plate 908, and the liquid recovery path 918 communicates with the openings in the even-numbered opening rows Oc. Therefore, four openings 820 communicate with each liquid supply path 916, and three openings 820 communicate with each liquid recovery path 918.
[0052] Although details will be described later, the liquid supply path 916 is connected to a common supply flow path 324, and the liquid recovery path 918 is connected to a common recovery flow path 328. For this reason, a pressure difference occurs between the liquid supply path 916 and the liquid recovery path 918. Therefore, in a discharge port that is not discharging ink while ink is being discharged from the discharge port 904 to perform recording, this pressure difference causes ink to flow from the liquid supply path 916 to the liquid recovery path 918 via the supply port 922, the pressure chamber 910, and the recovery port 924 (see the arrow in FIG. 9).
[0053] This flow of ink allows viscous ink, bubbles, foreign matter, and the like in the ejection ports 904 that are not ejecting ink and the corresponding pressure chambers 910 to be collected in the liquid recovery channel 918. It also makes it possible to prevent the ink from becoming viscous or the concentration of the coloring material from increasing in the ejection ports 904 and the pressure chambers 910. The ink collected in the liquid recovery channel 918 is transferred to the opening 820 of the cover plate 908, as will be described in detail later.
[0054] The heating elements 914 use thermal energy to bubble the ink, and the resulting bubble-forming pressure causes the ink in the pressure chambers 910 to be ejected from the corresponding ejection ports 904. Specifically, the heating elements 914 are electrically connected to terminals 604 provided near the end of the substrate 902 by electrical wiring (not shown) provided on the recording element substrate 400. The heating elements 914 generate heat based on a pulse signal input from the control unit 200 via the electrical wiring substrate 404 and the flexible wiring substrate 402, causing the ink to boil, and the ink in the pressure chambers 910 is ejected from the ejection ports 904 by the force of bubble formation caused by this boiling.
[0055] <Flow paths in the recording element substrate and flow paths in the flow path member> Next, a part of the flow path configuration in the circulation system 300 formed by the flow path provided in the recording element substrate 400 and the flow path of the flow path member 512 will be described. FIG. 10 is a diagram showing a part of the flow path configuration of the circulation system 300 formed by the recording element substrate 400 and the flow path member 512. FIG. 10(a) is a perspective view of the support member 600 and the recording element substrate 400 arranged on the arrangement position P when viewed from the other side (upper side) in the Z direction. FIG. 10(b) is a cross-sectional view taken along the line Xb-Xb in FIG. 10(a). FIG. 10(c) is a cross-sectional view taken along the line Xc-Xc in FIG. 10(a). In FIG. 10(a), some of the configuration is shown by dashed lines and dashed lines to facilitate understanding.
[0056] The recording element substrate 400 is joined to the support member 600 so that each opening 820 in each opening row Oc is located within the corresponding liquid communication port 602. When the ejection module 518 is placed at the arrangement position P, the support member 600 to which the recording element substrate 400 is joined is placed so that the liquid communication port 602 communicates with the communication port 700 provided at the arrangement position P in the first flow path member 514 (see FIG. 10(a)). As a result, each opening 820 in the odd-numbered opening rows Oc communicates with the communication port 700s communicating with the common supply flow path 324 via the liquid communication port 602 (see FIG. 10(b)). On the other hand, each opening 820 in the even-numbered opening rows Oc communicates with the communication port 700c communicating with the common recovery flow path 328 via the liquid communication port 602 (see FIG. 10(c)).
[0057] Therefore, in the discharge unit 304 including the recording element substrate and the flow path member, an ink supply path is formed in which ink passes through the common supply flow path 324, the communication port 700s, the liquid communication port 602, the opening 820, the liquid supply path 916, and the supply port 922 in this order to supply ink to the pressure chamber. The communication port 700s and the liquid communication port 602 in this ink supply path correspond to the individual supply flow path 330a provided between the common supply flow path 324 and the recording element substrate 400 (see FIG. 3). In addition, in the discharge unit 304, an ink recovery path is formed in which ink passes through the recovery port 924, the liquid recovery path 918, the opening 820, the liquid communication port 602, the communication port 700c, and the common recovery flow path 328 in this order to recover ink from the pressure chamber. The communication port 700c and the liquid communication port 602 in this ink recovery path correspond to the individual recovery flow path 330b.
[0058] <Heating mechanism in the recording element substrate> The recording element substrate 400 is provided with a plurality of temperature sensors 214 and a plurality of sub-heaters 216 (see FIG. 2). Although not shown, the sub-heaters 216 are provided for each of the areas obtained by dividing the region of the recording element substrate 400 in which the ejection ports 904 are formed into a plurality of areas. At least one of the temperature sensors 214 is provided for each of the areas. The temperature sensor 214 and the sub-heater 216 are connected to the control unit 200 via an electric circuit formed on the recording element substrate 400 and an electric circuit formed on the flexible wiring substrate 402. When the temperature detected by the temperature sensor 214 falls below a set temperature range, the control unit 200 drives the sub-heater 216 in the area corresponding to the temperature sensor 214 to heat the area. When the temperature detected by the temperature sensor 214 exceeds the temperature range, the control unit 200 stops driving the sub-heater 216 in the area corresponding to the temperature sensor 214 to stop heating the area.
[0059] This allows the temperature of the region in which the ejection ports 904 are formed in the recording element substrate 400 to be adjusted within a set range on an area-by-area basis. Furthermore, by maintaining the recording element substrate 400 within a set temperature range, the viscosity of the ink in the recording element substrate 400 is reduced, and the ink can be ejected and circulated appropriately. By performing such temperature control to suppress the temperature variation in the multiple recording element substrates 400, the temperature-induced variation in the ejection amount between the recording element substrates 400 is reduced, making it difficult for deterioration in recording quality to occur.
[0060] The set temperature of the recording element substrate 400 is preferably set to a temperature equal to or higher than the equilibrium temperature of the recording element substrate 400 when all the heating elements 914 are driven at the highest possible driving frequency. The temperature sensor 214 is, for example, a diode sensor. The heating mechanism of the recording element substrate 400 is not limited to the one using the sub-heater 216. The heating mechanism may be configured to use the heating element 914. Specifically, a voltage not enough to cause bubbling is applied to the heating element 914 to heat the corresponding area of the recording element substrate 400. The heating mechanism of the recording element substrate 400 may be configured to use the sub-heater 216 and the heating element 914 in combination.
[0061] <Temperature unevenness on the recording element substrate> Next, temperature unevenness occurring in the recording element substrate will be described. Ink is supplied to the recording element substrate 400 from the common supply flow path 324 via the communication port 700s and the liquid communication port 602 (see FIG. 10(b)). During recording, the temperature of the recording element substrate 400 rises together with the ink in the recording element substrate 400 due to heat generated by the heating element 914 and the sub-heater 216. For this reason, the ink flowing from the common supply flow path 324 into the recording element substrate 400 becomes lower in temperature than the temperature of the recording element substrate 400.
[0062] When the ink, which is at a relatively low temperature, flows from the common supply flow path 324 through the communication port 700s into the recording element substrate 400, the recording element substrate 400 is cooled in the vicinity of the opening 820 into which the ink flows. This causes a temperature difference between the vicinity of the opening 820 and a position spaced apart from the opening 820. This temperature difference causes a difference in the ink viscosity, which results in a difference in the amount of ink discharged between the discharge port in the vicinity of the opening 820 into which the ink flows and the discharge port spaced apart from the opening 820.
[0063] <Characteristic configuration of this embodiment> Here, as shown in FIG. 8(a), the region where the ejection ports 904 are formed in the recording element substrate 400 (hereinafter referred to as the "ejection region") is located closer to the other long side 400b than to the long side 400a where the terminals 604 are provided. That is, the sub-heater 216 and the heating element 914 are located in this ejection region, so the heating effect is high. On the other hand, in the region where the ejection ports 904 are not formed (hereinafter referred to as the "non-ejection region"), the sub-heater 216 and the heating element 914 are not located, so the heating effect is low and heat is dissipated. The non-ejection regions are located on both sides of the ejection region in the X direction. The non-ejection region on one side in the X direction where the long side 400a is located is formed larger than the non-ejection region on the other side in the X direction where the long side 400b is located. For this reason, in the recording element substrate 400, the long side 400a side is more likely to dissipate heat than the long side 400b side, so that the recording element substrate 400 is more likely to cool down. That is, of the two non-ejection regions with low heating effect, the non-ejection region on the long side 400a side has a relatively lower heating effect than the non-ejection region on the long side 400b side.
[0064] Therefore, in this embodiment, the recording element substrate 400 is arranged at the arrangement position P such that the long side 400a on which the non-ejection region is formed large is arranged on the side of the common recovery channel 328, and the long side 400b on which the non-ejection region is formed small is arranged on the side of the common supply channel 324 (see FIG. 11). Further, the recording element substrate 400 is arranged such that the ejection region is biased toward the long side 400b at the arrangement position P so that the ejection region is formed wider on the side of the common supply channel 324 than on the side of the common recovery channel 328. FIG. 11 is a diagram showing a state in which the ejection module 518 is arranged on the flow path member 512. Note that FIG. 11 is a view seen from the other side in the Z direction.
[0065] As a result, in the recording element substrate 400, the ink from the common supply channel 324 flows in on the long side 400b where the heating effect is relatively high, and the ink flows out to the common recovery channel 328 on the long side 400a where the heating effect is relatively low. That is, in the recording element substrate 400, the relatively low-temperature ink flows into the region where the heating effect is relatively high, and the relatively high-temperature ink flows out from the region where the heating effect is low. For this reason, the temperature difference between the vicinity of the ink inflow position and other positions in the recording element substrate 400, which occurs during the circulation of the ink in the circulation system 300, is reduced, and the recording element substrate 400 can be made to have a uniform temperature.
[0066] Further, the formation position of the communication port 700 formed at the arrangement position P in the flow path member 512 has the following relationship, for example. That is, when the minimum distance between the communication port 700s communicating with the common supply channel 324 and the long side 400b is L1in, and the minimum distance between the communication port 700c communicating with the common recovery channel 328 and the long side 400a is L1out, the relationship is L1in < L1out (see FIG. 12). FIG. 12 is a diagram for explaining the positions in the X direction of the communication ports 700s and 700c formed at the arrangement position P. Also, the minimum distance between the communication port 700s communicating with the common supply channel 324 and the end portion 514aa on the other side in the X direction of the bottom surface 514a is L2in, and the minimum distance between the communication port 700c communicating with the common recovery channel 328 and the end portion 514ab on one side in the X direction of the bottom surface 514a is L2out. At this time, the relationship between L2in and L2out is L2in < L2out.
[0067] The minimum distance between the communication port 700s (700c) and the corresponding long side 400b (400a) is based on the communication port 700s (700c) that is the shortest distance between the communication port 700s (700c) and the corresponding long side 400b (400a) among the multiple communication ports 700s (700c). The minimum distance between the communication port 700s (700c) and the corresponding end 514aa (514ab) is based on the communication port 700s (700c) that is the shortest distance between the communication port 700s (700c) and the corresponding end 514aa (514ab) among the multiple communication ports 700s (700c). As a result, the communication port 700s communicating with the common supply flow path 324 and the communication port 700c communicating with the common recovery flow path 328 are positioned approximately symmetrically with respect to the discharge port array group.
[0068] (Action and effect) As described above, in the recording head 16, of the non-ejection regions formed on both sides in the X direction of the ejection region where the heating effect is low, the non-ejection region where the heating effect is relatively low is arranged on the common recovery flow path side, and the recording element substrate 400 is arranged at arrangement position P of the flow path member 512. Also, in the recording element substrate 400, the ejection region where the heating effect is high is formed wider on the common supply flow path 324 side.
[0069] As a result, in the recording element substrate 400, ink at a relatively low temperature flows in from an area with a high heating effect, and ink at a relatively high temperature flows from an area with a low heating effect, so that the temperature of the recording element substrate 400 is uniformed. Therefore, the variation in the temperature of the circulating ink between the vicinity of the ink inflow position and other positions in the recording element substrate 400 is suppressed, and the variation in the amount of ink discharged is suppressed.
[0070] (Other embodiments) In the above embodiment, the recording head 16 is configured to eject one type of ink, but the present invention is not limited thereto, and the recording head 16 may be configured to eject multiple types of ink. Hereinafter, a recording head that ejects two types of ink will be described as an example, but the recording head 16 may be configured to eject three or more types of ink. FIG. 13 is a diagram for explaining a recording head that ejects two types of ink, where (a) is a cross-sectional view of the recording head corresponding to FIG. 10(b), and (b) is a diagram showing a recording element substrate arranged at the arrangement position P of the recording head. In FIG. 13, a common supply flow path 324a for one ink, a common recovery flow path 328a for one ink, a common supply flow path 324b for the other ink, and a common recovery flow path 328b for the other ink are formed from the other side to one side in the X direction. In the vicinity of the common supply flow path 324a provided on the end side of the recording element substrate 1300, it is easy to locally lower the temperature of the recording element substrate 1300. Therefore, by arranging the recording element substrate 1300 so that the heating area is wider on the other long side 1300b side, the ink circulating in the recording element substrate 1300 can be uniformly heated.
[0071] In the above embodiment, the heat generating element 914 is used as the printing element, but the present invention is not limited to this. If the sub-heater 216 is provided, a known energy generating element capable of generating energy for ejecting ink from the ejection port, such as a piezoelectric element, may be used as the printing element.
[0072] The disclosure of the above embodiment includes the following configurations and methods.
[0073] (Configuration 1) a substrate including a plurality of ejection ports capable of ejecting liquid, a supply port for supplying liquid to the plurality of ejection ports, a recovery port for recovering liquid not ejected from the plurality of ejection ports, and an energy generating element capable of generating energy for ejecting liquid from the ejection ports; a flow path member arranged on the substrate, the flow path member having a supply flow path for supplying liquid to the supply port on one side of the substrate in a first direction intersecting with an arrangement direction of the substrate, and a recovery flow path for recovering liquid from the recovery port on the other side of the first direction; a heating means for heating a discharge region in which the discharge ports are formed on the substrate, The liquid ejection head is characterized in that the substrate has the recovery flow path arranged on both sides of the ejection region in the first direction, on the side where the distance between the ejection region and an edge of the substrate in the first direction is relatively long, and the supply flow path arranged on the side where the distance between the ejection region and an edge of the substrate in the first direction is relatively long.
[0074] (Configuration 2) The liquid ejection head of Configuration 1, wherein the substrate is disposed on the flow path member such that the ejection region is positioned offset to one side in the first direction.
[0075] (Configuration 3) The energy generating element is a heating element, 3. The liquid ejection head according to configuration 1 or 2, wherein the heating means is at least one of a heater that is driven based on the temperature of the substrate and a heat generating element that is driven based on the temperature without ejecting liquid from the ejection port.
[0076] (Configuration 4) The liquid ejection head according to any one of configurations 1 to 3, wherein the substrate ejects a plurality of types of liquid.
[0077] (Configuration 5) the substrate is disposed on the flow path member via a support member that supports the substrate and has a liquid communication port that can fluidly connect the substrate and the flow path member; In the flow path member, a first communication port that communicates the supply flow path and the liquid communication port is located on one side of the substrate in the first direction, The liquid ejection head according to any one of configurations 1 to 4, wherein a second communication port that communicates the recovery channel with the liquid communication port is located on the other side of the substrate in the first direction.
[0078] (Configuration 6) A liquid ejection head described in configuration 5, wherein the distance between the first communication port and a first end of the substrate on one side in the first direction is shorter than the distance between the second communication port and a second end of the substrate on the other side in the first direction.
[0079] (Configuration 7) A liquid ejection head as described in configuration 5, wherein the distance between the first communication port and a third end on one side of the flow path member in the first direction is shorter than the distance between the second communication port and a fourth end on the other side of the flow path member in the first direction.
[0080] (Configuration 8) a substrate including a plurality of ejection ports capable of ejecting liquid, a supply port for supplying liquid to the plurality of ejection ports, a recovery port for recovering liquid not ejected from the plurality of ejection ports, and an energy generating element capable of generating energy for ejecting liquid from the ejection ports; a flow path member arranged on the substrate, the flow path member having a supply flow path for supplying liquid to the supply port on one side of the substrate in a first direction intersecting with an arrangement direction of the substrate, and a recovery flow path for recovering liquid from the recovery port on the other side of the first direction; a heating means for heating a discharge region in which the discharge ports are formed on the substrate, The substrate is a non-ejection region in which the ejection ports are not formed is formed on both sides of the ejection region in the first direction so that the heating effect of the heating means is different; A liquid ejection head characterized in that the flow path member is arranged so that the side where the heating effect is relatively low is located on one side in the first direction, and the side where the heating effect is relatively high is located on the other side in the first direction.
[0081] (Configuration 9) 9. The liquid ejection head according to configuration 8, wherein the substrate has terminals for electrical connection to an external device formed on a side of the non-ejection region where the heating effect is relatively low.
[0082] (Configuration 10) The energy generating element is a heating element, 9. The liquid ejection head according to configuration 8, wherein the heating means is at least one of a heater that is driven based on the temperature of the substrate and the heat generating element that is driven based on the temperature without ejecting liquid from the ejection port.
[0083] (Configuration 11) A liquid ejection head according to any one of configurations 1 to 10; a circulation system that supplies liquid to the liquid ejection head from a tank that stores the liquid, and transfers liquid recovered from the liquid ejection head to the tank. [Explanation of symbols]
[0084] 16 Recording head 216 Sub-heater 400 Recording element board 512 Flow path components 914 Heating element
Claims
1. A substrate comprising: a row of discharge ports arranged in a first direction, wherein a plurality of discharge ports capable of discharging liquid are arranged in a second direction; a liquid supply path for supplying liquid to the plurality of discharge ports; a liquid recovery path for recovering liquid that was not discharged from the plurality of discharge ports; and an energy generating element capable of generating energy for discharging liquid from the discharge ports. A flow path member is provided, which is arranged on one side of the second direction and comprises a common supply flow path for supplying liquid to a plurality of liquid supply paths, and a common recovery flow path for recovering liquid from a plurality of liquid recovery paths, and is arranged opposite the substrate. A liquid dispensing head having a heating means for heating the dispensing region in the substrate where the dispensing port is formed, The flow channel member comprises only one common supply channel and one common recovery channel, When comparing one side and the other side in the second direction that straddles the ejection region in the substrate, the distance between the ejection region and the edge of the substrate in the second direction is different. A liquid discharge head characterized in that, when viewed from the first direction, the substrate is arranged such that, in the second direction, the common recovery channel is located on the same side as the side with a relatively longer distance relative to the flow channel member, and the common supply channel is located on the same side as the side with a relatively shorter distance.
2. The liquid dispensing head according to claim 1, wherein the substrate is provided with a terminal for electrical connection to the outside on the side with the relatively longer distance.
3. The energy generating element is a heat generating element, The liquid discharge head according to claim 1, wherein the heating means is at least one of a heater driven based on the temperature of the substrate and a heating element driven based on the temperature of the substrate without discharging liquid from the discharge port.
4. The substrate is a liquid dispensing head according to claim 1, which dispenses one type of liquid.
5. The substrate and the flow channel member further include a support member for supporting the substrate, The support member is provided with a liquid communication port that allows liquid to flow between the substrate and the flow channel member. The liquid discharge head according to claim 1, wherein the flow path member comprises a first communication port that connects the common supply flow path and the liquid communication port, and a second communication port that connects the common recovery flow path and the liquid communication port.
6. The substrate has a first end on one side in the second direction and a second end on the other side in the second direction. The liquid discharge head according to claim 5, wherein the distance between the first communication port and the first end is shorter than the distance between the second communication port and the second end.
7. The liquid discharge head according to claim 5, wherein the distance between the first communication port and the third end on one side of the flow path member in the second direction is shorter than the distance between the second communication port and the fourth end on the other side of the flow path member in the second direction.
8. A substrate comprising: a row of discharge ports arranged in a first direction, wherein a plurality of discharge ports capable of discharging liquid are arranged in a second direction; a liquid supply path for supplying liquid to the plurality of discharge ports; a liquid recovery path for recovering liquid that was not discharged from the plurality of discharge ports; and an energy generating element capable of generating energy for discharging liquid from the discharge ports. A flow path member is provided, which is arranged on one side of the second direction and comprises a common supply flow path for supplying liquid to a plurality of liquid supply paths, and a common recovery flow path for recovering liquid from a plurality of liquid recovery paths, and is arranged opposite the substrate. A liquid dispensing head having a heating means for heating the dispensing region in the substrate where the dispensing port is formed, In the substrate, two non-discharge regions are formed on both sides of the discharge region in the second direction, where the discharge port is not formed, and the two non-discharge regions are configured such that the heating effect by the heating means is relatively different. A liquid discharge head characterized in that, when viewed from the first direction, the substrate is arranged such that the common recovery channel is located on the same side as the side with a relatively low heating effect in the second direction, and the common supply channel is located on the same side as the side with a relatively high heating effect, relative to the flow channel member.
9. The liquid dispensing head according to claim 8, wherein the substrate is provided with a terminal for electrical connection to the outside in the non-dispensing region of the two non-dispensing regions that has a relatively lower heating effect.
10. The energy generating element is a heat generating element, The liquid discharge head according to claim 8, wherein the heating means is at least one of a heater driven based on the temperature of the substrate and a heating element driven based on the temperature of the substrate without discharging liquid from the discharge port.
11. A liquid dispensing head according to any one of claims 1 to 10, A liquid dispensing device having a circulation system that supplies liquid from a liquid storage tank to a liquid dispensing head and transfers the liquid recovered from the liquid dispensing head back to the tank.