Substrate for liquid ejection head, liquid ejection head, and liquid ejection apparatus

Abstract

To provide a technology capable of efficiently dissipating heat in a recording element substrate equipped with a temperature adjustment heating element.SOLUTION: A substrate for a liquid ejection head is capable of ejecting a liquid using energy generated by an energy generating element and includes: a base; a first heat transfer layer which is provided below the energy generating element and formed laminated on the base via an insulating layer; a temperature adjustment heating element configured to be capable of adjusting temperatures of the liquid and the substrate for the liquid ejection head; and first heat transfer members connecting the first heat transfer layer with the base. The first heat transfer members are provided between the adjacent energy generating elements and between the energy generating element and the temperature adjustment heating element.SELECTED DRAWING: Figure 13

Description

[Technical field]

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

[0002] In a recording element substrate mounted on a recording head that ejects ink by an inkjet method, ink is ejected from a nozzle using, for example, thermal energy generated by electrothermal conversion elements as recording elements. In recent years, in order to improve the performance of the recording element substrate, for example, a temperature detection element for detecting the temperature of the recording element when it is driven, a temperature control heating element for controlling the temperature of the ink and the recording element substrate, etc., have been provided on the recording element substrate, and the number of recording elements mounted has been increased.

[0003] For this reason, the components mounted on the printing element substrate are arranged at high density, and new heat sources such as temperature control heating elements are added, so efficient heat dissipation is required. Patent Document 1 discloses a technology for efficiently dissipating heat generated by the printing elements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-198936 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology disclosed in Patent Document 1 does not take into consideration the placement of temperature detection elements, temperature control heating elements, etc., and it is difficult to obtain a sufficient heat dissipation effect in a highly functional recording element substrate equipped with these elements.

[0006] The present invention has been made in view of the above problems, and has an object to provide a technique capable of efficiently dissipating heat in a recording element substrate on which temperature control heat generating elements are mounted. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, one embodiment of the present invention is a substrate for a liquid ejection head capable of ejecting liquid using energy generated by an energy generating element, comprising a base, a first heat transfer layer provided directly below the energy generating element and formed by laminating on the base via an insulating layer, a temperature control heat generating element capable of adjusting the temperature of the liquid and the substrate for the liquid ejection head, and a first heat transfer member connecting the first heat transfer layer and the base, wherein the first heat transfer member is provided between adjacent energy generating elements and between the energy generating elements and the temperature control heat generating element. Effect of the Invention

[0008] According to the present invention, it becomes possible to efficiently dissipate heat in a recording element substrate on which temperature control heat generating elements are mounted. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a recording apparatus. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 4 is a diagram showing a flow path configuration in a flow path member. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 4 is a diagram showing the layout positions of some of the wiring on the recording element substrate. [Figure 11] FIG. 4 is a diagram for explaining the arrangement of adjacent recording element substrates. [Figure 12] FIG. [Figure 13] FIG. [Figure 14] 5A and 5B are diagrams for explaining the behavior of negatively charged particles in a pressure chamber. [Figure 15] FIG. 13 is a diagram showing a modified example of an electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an example of an embodiment of a liquid ejection head substrate, a liquid ejection head, and a liquid ejection device will be described in detail with reference to the attached 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.

[0011] In this specification, a recording apparatus configured to eject ink from a recording head including a recording element substrate will be described as an example of a liquid ejection apparatus configured to eject liquid from a liquid ejection head including a liquid ejection head substrate.

[0012] (Recording device) Fig. 1 is a schematic diagram of a recording device. The recording device 10 in Fig. 1 includes a transport unit 12 that transports a recording medium M, and a recording head 14 that ejects ink onto the recording medium M to perform recording. The recording device 10 is a line-type recording device that performs continuous recording in one pass while transporting a plurality of recording media M continuously or intermittently. Note that the recording media M are not limited to cut sheets, and may be continuous roll paper.

[0013] The recording head 14 is a line-type recording head extending in a direction intersecting (orthogonal in this embodiment) the transport direction of the recording medium M. In this embodiment, the recording head 14 is configured to be capable of ejecting four types of ink: cyan (C) ink, magenta (M) ink, yellow (Y) ink, and black (K) ink. In other words, the recording device 10 is configured to be capable of recording in full color using these inks.

[0014] The print head 14 is fluidly connected to a supply unit 224 (described later), a main tank 202 (described later), and a buffer tank 204 (described later). In the printing apparatus 10, the print head 14 forms an ink circulation path (described later) together with the supply unit 224, the buffer tank 204, etc. The printing apparatus 10 also includes an electrical control unit (not shown) that transmits power, ejection control signals, etc. to the print head 14.

[0015] (Circulation route) The recording device 10 supplies ink to the recording head 14, and includes a circulation path capable of circulating the ink to be supplied to the recording head 14 while recovering the ink supplied to the recording head 14. In this embodiment, two circulation paths can be formed. The two circulation paths applicable to this embodiment will be described in detail below.

[0016] <First circulation route> First, a first circulation path as one form of a circulation path applicable to the recording device 10 according to this embodiment will be described. Fig. 2(a) is a diagram showing a first circulation path as one form of a circulation path applicable to the recording device 10 according to this embodiment. Note that Fig. 2(a) shows a circulation path for one ink. Since the recording device 10 is configured to be able to eject four different inks, the circulation path shown in Fig. 2(a) is provided for each type of ink.

[0017] In the recording device 10, the recording head 14 and a buffer tank 204 capable of storing ink supplied from a main tank 202 are connected via flow paths 206, 208, and 210 to form a first circulation path 200. In the first circulation path 200, ink is circulated between the buffer tank 204 and the recording head 14 by driving three pumps 212, 214, and 216. Specifically, the flow path 206 is provided with a pump 212, and ink stored in the buffer tank 204 is supplied to the recording head 14 by driving the pump 212. In addition, the flow path 208 is provided with a pump 214 (high pressure side), and the flow path 210 is provided with a pump 216 (low pressure side). By driving these pumps 214 and 216, ink is sucked from the recording head 14, and the sucked ink is transferred to the buffer tank 204.

[0018] The buffer tank 204 is provided with an air communication port (not shown) that communicates between the inside and the outside, and is configured to be able to discharge air bubbles generated in the stored ink to the outside. The buffer tank 204 is also connected to the main tank 202 via a flow path 218. A pump 220 is provided in the flow path 218. In the recording device 10, for example, when ink is consumed in the recording head 14 and the ink stored in the buffer tank 204 falls below a certain amount, the pump 220 is driven to supply the ink stored in the main tank 202 to the buffer tank 204. In the recording head 14, ink is consumed when ink is discharged (ejected) from the nozzles of the recording head 14, for example, when ink contributing to recording is discharged and ink not contributing to recording is discharged.

[0019] The pumps 214 and 216 are preferably positive displacement pumps having a quantitative liquid delivery capability. Specifically, the positive displacement pumps include tube pumps, gear pumps, diaphragm pumps, and syringe pumps. Alternatively, instead of using such pumps, a constant flow rate may be ensured by disposing a general constant flow valve or relief valve at the pump outlet. In addition, the flow path 208 in which the pump 214 is provided is connected to a common supply flow path 230 (described later) in the recording head 14, and the flow path 210 in which the pump 216 is provided is connected to a common recovery flow path 232 (described later) in the recording head 14.

[0020] When the recording head 14 is driven, a certain amount of ink is sucked from the common supply flow path 230 and the common recovery flow path 232 by the pumps 214 and 216. The flow rate during suction is set to a level at which the temperature difference between the recording element substrates 228 (described later) in the recording head 14 does not affect the recording quality. If a flow rate is set too high, the negative pressure difference between the recording element substrates 228 becomes too large due to the influence of pressure loss in the flow paths in the ejection unit 222, resulting in uneven density of the image. For this reason, the flow rate is set taking into consideration the temperature difference and negative pressure difference between the recording element substrates 228.

[0021] The recording head 14 includes a discharge unit 222 that discharges ink, and a supply unit 224 that supplies ink to the discharge unit 222 and collects ink flowing out from the discharge unit 222 .

[0022] The supply unit 224 supplies the ink supplied via the flow path 206 to the ejection unit 222 via the negative pressure control unit 226. The negative pressure control unit 226 operates so that the pressure fluctuation downstream of the negative pressure control unit 226 (i.e., the ejection unit 222 side) falls within a certain range even when the flow rate in the circulation path fluctuates due to a change in the print duty during printing. The pressure fluctuation is kept within a certain range, for example, centered on a preset pressure.

[0023] The negative pressure control unit 226 includes two negative pressure adjustment mechanisms 226a and 226b. Any mechanism may be used for the negative pressure adjustment mechanisms 226a and 226b as long as it can control the pressure downstream of the negative pressure adjustment mechanisms 226a and 226b within a certain range of fluctuation centered on a desired set pressure. Of the negative pressure adjustment mechanisms 226a and 226b, the negative pressure adjustment mechanism 226a on the relatively high pressure setting side is connected to the common supply flow path 230 of the discharge unit 222 via the supply unit 224. The negative pressure adjustment mechanism 226b on the relatively low pressure setting side is connected to the common recovery flow path 232 of the discharge unit 222 via the supply unit 224.

[0024] As an example of the negative pressure adjustment mechanisms 226a and 226b, a configuration similar to a so-called pressure reducing regulator can be adopted. When a pressure reducing regulator is used, it is preferable to use a configuration in which the pump 212 pressurizes the upstream side of the negative pressure control unit 226 via the supply unit 224. With such a configuration, it is possible to suppress the influence of the head difference between the buffer tank 204 and the recording head 14, and it is possible to increase the degree of freedom in the layout of the buffer tank 204 of the recording device 10.

[0025] The pump 212 may be any pump having a head pressure equal to or higher than a certain pressure within the range of the ink circulation flow rate used when driving the recording head 14, and may be a turbo pump, a positive displacement pump, or the like. Specifically, a diaphragm pump or the like may be used as the pump 212. Also, instead of the pump 212, for example, a water head tank disposed with a certain water head difference with respect to the negative pressure control unit 226 may be used.

[0026] A plurality of recording element substrates 228 capable of ejecting ink are arranged in the ejection unit 222. In addition, in the ejection unit 222, a common supply flow path 230 to which ink supplied from the supply unit 224 is supplied, and a common recovery flow path 232 through which the supplied ink flows out to the supply unit 224 are provided extending along the arrangement direction of the recording element substrates 228. The common supply flow path 230 is connected to each recording element substrate 228 via an individual supply flow path 234. In addition, the common recovery flow path 232 is connected to each recording element substrate 228 via an individual recovery flow path 236.

[0027] As a result, the common supply flow path 230 and the common recovery flow path 232 communicate with each other via the individual supply flow paths 234, the recording element substrate 228, and the individual recovery flow paths 236. The common supply flow path 230 is connected to the negative pressure adjustment mechanism 226a and maintained at a relatively high pressure, while the common recovery flow path 232 is connected to the negative pressure adjustment mechanism 226b and maintained at a relatively low pressure, creating a pressure difference between the two flow paths. As a result, a portion of the ink supplied to the common supply flow path 230 flows into the common recovery flow path 232 via the individual supply flow paths 234, the recording element substrate 228, and the individual recovery flow paths 236.

[0028] With this configuration, in the ejection unit 222, ink flows in the common supply flow path 230 and the common recovery flow path 232, while a part of the ink passes through each recording element substrate 228. Therefore, heat generated in each recording element substrate 228 is discharged to the outside of the recording element substrate 228 by the ink flowing from the common supply flow path 230 to the common recovery flow path 232. In addition, during recording by the recording head 14, ink flows can be generated even in nozzles and pressure chambers that are not ejecting ink for recording. This makes it possible to suppress the viscosity of the ink in the nozzles and pressure chambers, and to discharge the viscosity-increased ink and foreign matter in the ink in the recording element substrate 228 to the outside of the recording element substrate 228, enabling high-speed, high-quality recording.

[0029] <Second circulation route> Next, a second circulation path as one form of a circulation path applicable to the recording device 10 according to this embodiment will be described. FIG. 2(b) is a diagram showing a second circulation path as one form of a circulation path applicable to the recording device 10 according to this embodiment. Note that FIG. 2(b) shows a circulation path for one ink. Since the recording device 10 is configured to be able to eject four different inks, the circulation path shown in FIG. 2(b) is provided for each type of ink. Below, the main differences from the first circulation path 200 will be described.

[0030] First, in the second circulation path 250, ink is supplied to the recording head 14 via the flow paths 208 and 210 by driving the pumps 214 and 216. Also, ink is sucked from the recording head 14 via the flow path 206 by driving the pump 212, and the sucked ink is transferred to the buffer tank 204. Then, a negative pressure control unit 226 is disposed downstream of the recording head 14. Negative pressure adjustment mechanisms 226a and 226b constituting the negative pressure control unit 226 each have a mechanism (a mechanism having the same function as a so-called "back pressure regulator") that controls the pressure upstream of the negative pressure control unit 226 within a certain range centered on a desired set pressure.

[0031] The negative pressure control unit 226 in the second circulation path 250 operates so that the pressure fluctuation on the upstream side (i.e., the ejection unit 222 side) of the negative pressure control unit 226 is within a certain range even if the flow rate fluctuates due to a change in the recording duty during recording by the recording head 14. The pressure fluctuation is, for example, kept within a certain range centered on a preset pressure. It is preferable that the pump 212 pressurizes the downstream side of the negative pressure control unit 226 via the supply unit 224. By applying such pressure, the influence of the head pressure of the buffer tank 204 on the recording head 14 can be suppressed. This increases the degree of freedom in the layout of the buffer tank 204 in the recording device 10. Instead of the pump 212, for example, a head tank arranged with a predetermined head difference with respect to the negative pressure control unit 226 may be used.

[0032] Similarly to the first circulation path 200, the negative pressure control unit 226 in the second circulation path 250 includes two negative pressure adjustment mechanisms 226a and 226b, which are set with different control pressures. Of the two negative pressure adjustment mechanisms 226a and 226b, the negative pressure adjustment mechanism 226a, which is set with a relatively high pressure, is connected to the common supply flow path 230 of the ejection unit 222 via the supply unit 224. The negative pressure adjustment mechanism 226b, which is set with a relatively low pressure, is connected to the common recovery flow path 232 of the ejection unit 222 via the supply unit 224. The two negative pressure adjustment mechanisms 226a and 226b make the pressure of the common supply flow path 230 relatively higher than the pressure of the common recovery flow path 232. For this reason, a part of the ink supplied to the common supply flow path 230 flows to the common recovery flow path 232 via the individual supply flow paths 234, the recording element substrate 228, and the individual recovery flow paths 236.

[0033] With this configuration, in the second circulation path 250, a flow of ink occurs in the ejection unit 222 similar to that of the first circulation path 200, but two advantages different from the first circulation path 200 can be obtained. The first advantage is that in the second circulation path 250, since the negative pressure control unit 226 is disposed downstream of the print head 14, there is less concern that dust or foreign matter generated in the negative pressure control unit 226 will flow into the print head 14. The second advantage is that in the second circulation path 250, the maximum flow rate required to supply ink from the buffer tank 204 to the print head 14 can be smaller than that in the first circulation path 200.

[0034] Specifically, the total flow rate in the common supply flow path 230 and the common recovery flow path 232 during circulation during standby for recording is defined as A. The value of A is defined as the minimum flow rate required to keep the temperature difference in the discharge unit 222 within a desired range when adjusting the temperature of the print head 14 during standby for recording. In addition, the discharge flow rate when ink is discharged from all nozzles of the discharge unit 222 (hereinafter referred to as "full discharge") is defined as F.

[0035] Then, in the first circulation path 200, the set flow rates of the pumps 214, 216 are A, so the maximum amount of ink supply required to the recording head 14 during full ejection is A+F. On the other hand, in the second circulation path 250, the amount of ink supply required to the recording head 14 during recording standby is A. And the amount of ink supply required to the recording head 14 during full ejection is F. Therefore, in the second circulation path 250, the sum of the set flow rates of the pumps 214, 216, that is, the maximum amount of required supply, is the larger of A and F.

[0036] Therefore, as long as the discharge unit 222 of the same configuration is used, the maximum value of the required supply amount in the second circulation path 250 (A or F) is always smaller than the maximum value of the required supply amount in the first circulation path 200 (A+F). Therefore, the second circulation path 250 improves the degree of freedom of the pump to be used. This makes it possible to use, for example, a low-cost pump with a simple configuration, and to reduce the load on a cooler (not shown) installed in the flow path on the main body side, thereby suppressing manufacturing costs. In a line-type recording head, the above-mentioned value of A or F is relatively large. Therefore, the longer the line head is in the direction intersecting the conveying direction of the recording medium, the more advantages it can enjoy in the second circulation path 250.

[0037] The first circulation path 200 also has an advantage. Specifically, in the second circulation path 250, the flow rate flowing through the discharge unit 222 during recording standby is maximized, so that the lower the recording duty, the higher the negative pressure applied to each nozzle. For this reason, particularly when the flow path width (flow path diameter) of the common supply flow path 230 and the common recovery flow path 232 is reduced to reduce the head width (length in the short direction of the recording head 14), a high negative pressure is applied to the nozzle in a low duty image in which unevenness is easily visible. There is a risk that the effect of satellite droplets will be large due to the application of such a high negative pressure. On the other hand, in the first circulation path 200, the timing at which a high negative pressure is applied to the nozzle is when a high duty image is formed, so even if satellite droplets are generated, they are difficult to be visually recognized, and the effect on the recorded image is small. Therefore, in the recording device 10, a preferable circulation flow path is selected in consideration of the specifications of the recording head 14 and the recording device 10 (such as the discharge flow rate F, the minimum circulation flow rate A, and the flow path resistance in the recording head).

[0038] (Recording head) Next, the configuration of the recording head 14 will be described. Fig. 3 is a perspective view of the recording head 14, where (a) is a view seen from below on one side in the transport direction, and (b) is a view seen from above on the other side in the transport direction. Fig. 4 is an exploded configuration diagram of the recording head 14.

[0039] In the recording head 14, a plurality of recording element substrates 228 are arranged along the extension direction of the recording head 14 on the surface facing the recording medium M transported in the transport direction by the transport unit 12 (see FIG. 3(a)). In this embodiment, the recording head 14 is provided with 15 recording element substrates 228, and each recording element substrate 228 is configured to be able to eject four types of ink: C ink, M ink, Y ink, and K ink.

[0040] The recording head 14 includes a signal input terminal 306 and a power supply terminal 308 electrically connected to each recording element substrate 228 via a flexible wiring board 302 and an electric wiring board 304 (see FIGS. 3(a) and 3(b)). The signal input terminal 306 and the power supply terminal 308 are electrically connected to an electric control unit (not shown) of the recording device 10. Each recording element substrate 228 is supplied with an ejection control signal from the electric control unit via the signal input terminal 306, and is supplied with power required for ejection from the electric control unit via the power supply terminal 308.

[0041] By consolidating the wiring using the electric circuit in the electric wiring board 304, the number of signal input terminals 306 and power supply terminals 308 is reduced compared to the number of recording element boards 228. This reduces the number of electrical connections that need to be removed when assembling the recording head 14 to the recording device 10 or when replacing the recording head 14.

[0042] The recording head 14 has connection parts 310 near both ends in the extension direction that are connected to flow paths in the circulation path. Ink is supplied to the recording head 14 from the flow paths in the circulation path provided for each type of ink via the corresponding connection parts 310. Ink also flows out of the recording head 14 to the flow paths in the circulation path provided for each type of ink via the corresponding connection parts 310.

[0043] The recording head 14 includes a housing 402 to which a supply unit 224 and an electric wiring board 304 are attached (see FIG. 4). A connection portion 310 is provided in the supply unit 224. A filter 240 (see FIGS. 2(a) and (b)) for removing foreign matter from the ink being supplied is provided inside the supply unit 224. In this embodiment, the recording head 14 includes two supply units 224, each of which is provided with flow paths for two colors and a filter 240. A negative pressure control unit 226 is connected to the supply unit 224, and the ink supplied to the supply unit 224 is supplied to the corresponding negative pressure control unit 226.

[0044] The negative pressure control unit 226 is a unit equipped with negative pressure adjustment mechanisms 226a and 226b, and the pressure loss change in the circulation path caused by the fluctuation of the ink flow rate is significantly attenuated by the action of valves, spring members, etc. provided inside. For this reason, the two negative pressure adjustment mechanisms 226a and 226b are set to different control pressures, and the negative pressure adjustment mechanism 226a on the high pressure side is connected to the common supply flow path 230 of the ejection unit 222, and the negative pressure adjustment mechanism 226b on the low pressure side is connected to the common recovery flow path 232 of the ejection unit 222.

[0045] The housing 402 includes a discharge unit support part 404 that supports the discharge unit 222 and an electric wiring board support part 406 that supports the electric wiring board 304, and ensures the rigidity of the recording head 14. The electric wiring board support part 406 is fixed to the discharge unit support part 404 by screwing. The discharge unit support part 404 corrects warping and deformation of the discharge unit 222 to ensure the relative position accuracy of the multiple recording element boards 228. This suppresses streaks and unevenness in the recorded image caused by the relative position accuracy. Therefore, the discharge unit support part 404 preferably has sufficient rigidity, and is preferably made of, for example, a metal material such as SUS (Stainless Used Steel) or aluminum, or a ceramic such as alumina. In addition, the discharge unit support part 404 is provided with openings 410 and 412 into which a joint rubber 408 is inserted. The ink supplied from the supply unit 224 is led to a third flow path member 426 (described later) of the discharge unit 222 through the joint rubber 408.

[0046] The ejection unit 222 includes an ejection module 414 including a recording element substrate 228, and a flow path member 416 that distributes ink from the supply unit 224 to the recording element substrate 228 and guides ink flowing out from the recording element substrate 228 to the supply unit 224. The ejection unit 222 also includes a cover member 418 that protects the periphery of the arranged recording element substrates 228.

[0047] The discharge module 414, details of which will be described later, includes a recording element substrate 228 and a flexible wiring substrate 302. The flow path member 416 is formed by laminating a first flow path member 422, a second flow path member 424, and a third flow path member 426. The flow path member 416 is fixed to the discharge unit support portion 404 by screws, which suppresses warping and deformation of the flow path member 416.

[0048] The cover member 418 is a member having a frame-shaped surface in which an opening 420 is provided, which opens long in the extension direction of the recording head 14. The recording element substrate 228 and a sealant 510 (described later) in each ejection module 414 are exposed from the opening 420. The frame portion around the opening 420 serves as a contact surface for a cap member (not shown) for protecting the recording head 14 during standby for recording. For this reason, an adhesive, sealant, filler, or the like is applied along the periphery of the opening 420 to fill in unevenness and gaps on the surface where the recording element substrate 228 in the ejection unit 222 is exposed, so that a closed space is formed between the cap member and the surface during capping.

[0049] (Discharge module) Next, a description will be given of the discharge module 414. Figure 5 is a schematic diagram of the discharge module 414, where (a) is a perspective view and (b) is an exploded view.

[0050] The ejection module 414 includes a recording element substrate 228, a flexible wiring substrate 302 that electrically connects the recording element substrate 228 and an electric wiring substrate 304, and a support member 502 that supports the recording element substrate 228 and one end side of the flexible wiring substrate 302. The support member 502 is provided with a communication port 504 that communicates with an opening 804 (described later) provided in the recording element substrate 228.

[0051] The recording element substrate 228 is bonded to the support member 502 on a surface facing the nozzle forming surface 228a such that the opening 804 of the recording element substrate 228 communicates with the communication port 504. The flexible wiring substrate 302 is electrically connected by wire bonding to terminals 922 (described later) formed on the nozzle forming surface 228a of the recording element substrate 228, with one end side on which the terminals 506 are provided being supported by the support member 502. The wire bonding portion, i.e., the electrically connected portion, is sealed with a sealant 510.

[0052] A terminal 512 is provided on the other end side of the flexible wiring board 302, and the terminal 512 is electrically connected to a connection terminal 428 (see FIG. 4) of the electric wiring board 304. The support member 502 is a support body that supports the recording element substrate 228, and is also a flow path member that fluidly connects the recording element substrate 228 and the flow path member 416. For this reason, the support member 502 is preferably made of a material that has a high degree of flatness and can be joined to the recording element substrate 228 with sufficiently high reliability. Specifically, the support member 502 is made of, for example, alumina or a resin material.

[0053] (Flow path components) Next, the detailed configuration of the flow path member 416 will be described.

[0054] <First Flow Path Member 422, Second Flow Path Member 424, and Third Flow Path Member 426> First, the configuration of the first flow path member 422, the second flow path member 424, and the third flow path member 426 in the flow path member 416 will be described. FIG. 6 is a configuration diagram of the first flow path member 422, the second flow path member 424, and the third flow path member 426. FIG. 6(a) is a diagram showing one surface 422a of the first flow path member 422, which is a surface on which the discharge module 414 is arranged, and FIG. 6(b) is a diagram showing the other surface 422b of the first flow path member 422, which is a surface that is joined to one surface 424a of the second flow path member 424. FIG. 6(c) is a diagram showing one surface 424a of the second flow path member 424, and FIG. 6(d) is a diagram showing the other surface 424b of the second flow path member 424, which is a surface that is joined to one surface 426a of the third flow path member 426. 6(e) is a diagram showing one surface 426a of the third flow path member 426, and FIG. 6(f) is a diagram showing the other surface 426b of the third flow path member 426, which is the surface that abuts against the discharge unit support part 404.

[0055] A plurality of (eight in this embodiment) common flow channel grooves 602 are formed on the other surface 424b of the second flow channel member 424 along the extension direction of the second flow channel member 424 (see FIG. 6(d)). A common flow channel groove 604 is formed on one surface 426a of the third flow channel member 426 (see FIG. 6(e)). The common flow channel grooves 604 are provided at positions corresponding to the respective common flow channel grooves 602 provided on the other surface 424b when the one surface 426a of the third flow channel member 426 is joined to the other surface 424b of the second flow channel member 424, and the number of the common flow channel grooves 604 corresponds to the respective common flow channel grooves 602. As a result, when the second flow channel member 424 and the third flow channel member 426 are joined, eight common flow channels are formed by the common flow channel grooves 602 and the common flow channel grooves 604. These common channels become the common supply flow channel 230 and the common recovery flow channel 232 formed for each ink (see FIG. 7).

[0056] The third flow path member 426 is provided with communication openings 606 penetrating from one surface 426a to the other surface 426b (see FIGS. 6(e) and 6(f)). The communication openings 606 are provided on both end sides in the extension direction of the third flow path member 426, and on the one surface 426a, they are located at both ends of each common flow path groove 604. Furthermore, when the third flow path member 426 is fixed to the discharge unit support part 404, the communication openings 606 communicate with a flow path (not shown) provided in the joint rubber 408, thereby fluidly connecting the third flow path member 426 and the supply unit 224.

[0057] The second flow path member 424 is provided with communication openings 608 penetrating from one surface 424a to the other surface 424b (see FIGS. 6(c) and 6(d)). A plurality of communication openings 608 are formed in each common flow path groove 602, and are formed at positions that communicate with individual flow path grooves 610 (described later) provided in the first flow path member 422 when the second flow path member 424 and the first flow path member 422 are joined together.

[0058] The first flow path member 422 is provided with an individual flow path groove 610 formed on the other surface 422b, inclined with respect to the short-side direction of the first flow path member 422 (direction perpendicular to the extending direction of the first flow path member 422) (see FIG. 6(b)). The first flow path member 422 is provided with a communication port 612 penetrating from one surface 422a to the other surface 422b (see FIGS. 6(a)(b)). The communication port 612 is located in an area located in the center of the short-side direction of the first flow path member 422. The communication port 612 is provided at a position where it is fluidically connected to the recording element substrate 228 via the communication port 504 of the support member 502 when the ejection module 414 is disposed on the one surface 422a of the first flow path member 422. The communication port 612 is located at one end of the individual flow path groove 610. The individual flow passage groove 610 communicates with the communication port 608 at the other end.

[0059] The first flow path member 422, the second flow path member 424, and the third flow path member 426 are preferably made of a material that is resistant to corrosion by ink and has a low linear expansion coefficient. Specific examples of the material that can be used include composite materials (resin materials) made of alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), and PSF (polysulfone) as a base material to which inorganic fillers such as silica particles and fibers are added. The flow path member 416 is formed by laminating the first flow path member 422, the second flow path member 424, and the third flow path member 426 and bonding them to each other. When the first flow path member 422, the second flow path member 424, and the third flow path member 426 are made of a resin composite resin material, they may be joined by welding.

[0060] <Flow path in flow path member> Next, the flow paths formed in the flow path member 416 will be described. Fig. 7 shows the flow paths formed in the flow path member 416, where (a) is a partially enlarged view and (b) is a cross-sectional view taken along line VIIb-VIIb in (a). Fig. 7(a) is a view seen from one surface 422a of the first flow path member 422, with the flow paths formed therein indicated by dashed lines and the recording element substrate 228 disposed above indicated by a two-dot chain line.

[0061] The flow path member 416 is provided with a common supply flow path 230 and a common recovery flow path 232 extending in the longitudinal direction of the recording head 14 so as to correspond to each ink (see FIG. 7(a)). In FIG. 7(a), the common supply flow path 230a and the common recovery flow path 232a correspond to the same ink, and the common supply flow path 230b and the common recovery flow path 232b correspond to the same ink. In addition, the common supply flow path 230c and the common recovery flow path 232c correspond to the same ink, and the common supply flow path 230d and the common recovery flow path 232d correspond to the same ink.

[0062] A plurality of individual supply flow paths 234 formed by individual flow path grooves 610 are connected to the common supply flow path 230 via communication ports 608. Specifically, the individual supply flow path 234a is connected to the common supply flow path 230a via the communication port 608, and the individual supply flow path 234b is connected to the common supply flow path 230b via the communication port 608. Furthermore, the individual supply flow path 234c is connected to the common supply flow path 230c via the communication port 608, and the individual supply flow path 234d is connected to the common supply flow path 230d via the communication port 608.

[0063] Furthermore, a plurality of individual recovery flow paths 236 formed by individual flow path grooves 610 are connected to the common recovery flow path 232 via communication ports 608. Specifically, the individual recovery flow path 236a is connected to the common recovery flow path 232a via the communication port 608, and the individual recovery flow path 236b is connected to the common recovery flow path 232b via the communication port 608. Furthermore, the individual recovery flow path 236c is connected to the common recovery flow path 232c via the communication port 608, and the individual recovery flow path 236d is connected to the common recovery flow path 232d via the communication port 608.

[0064] With this configuration, the common supply flow path 230 can be fluidly connected to the recording element substrate 228 arranged in the center of the flow path member 416 via the individual supply flow paths 234, and the common recovery flow path 232 can be fluidly connected to the recording element substrate 228 arranged in the center of the flow path member 416 via the individual recovery flow paths 236.

[0065] When the discharge module 414 is placed on the flow path member 416, the individual recovery flow path 236 communicates with the discharge module 414 via the communication port 612 (see FIG. 7(b)). Although not shown in cross section, when the discharge module 414 is placed on the flow path member 416, the individual supply flow path 234 also communicates with the discharge module 414 via the communication port 612.

[0066] As a result, the flow path member 416 is fluidly connected to a pressure chamber 920 (described later) provided in the recording element substrate 228 via the support member 502. Note that, in the pressure chamber 920, a recording element 918 and a nozzle 802 are arranged, as described later.

[0067] Here, the common supply flow path 230 is connected to the negative pressure control unit 226 (negative pressure adjustment mechanism 226a) via the supply unit 224, and the common recovery flow path 232 is connected to the negative pressure control unit 226 (negative pressure adjustment mechanism 226b) via the supply unit 224. Therefore, a pressure difference is generated between the common supply flow path 230 and the common recovery flow path 232 by the negative pressure control unit 226. As a result, in the recording head 14, a portion of the ink supplied for each ink flows in the order of the common supply flow path 230, the individual supply flow path 234, the recording element substrate 228, the individual recovery flow path 236, and the common recovery flow path 232.

[0068] (Flow path configuration in the recording element substrate) Next, the flow path configuration in the recording element substrate 228 will be described. Fig. 8 is an external view of the recording element substrate 228, where (a) is a view seen from the nozzle forming surface on which nozzles are formed, and (b) is a view seen from the abutment surface that abuts against the support member 502. Fig. 9 is a view showing the configuration of the recording element substrate 228, where (a) is an enlarged view of the inside of frame IXa in Fig. 8(a), and (b) is a cross-sectional view along line IXb-IXb in Fig. 8(a). Fig. 10 is a view showing a circuit provided in frame X in Fig. 8(a).

[0069] The recording element substrate 228 has four nozzle rows formed on one surface, each row ejecting a different ink (see FIG. 8(a)). In each nozzle row, a plurality of nozzles 802 are arranged along the extension direction of the recording element substrate 228. In addition, the recording element substrate 228 has an opening 804 on the other surface opposite to the one surface, the opening 804 being fluidly connected to the communication port 504 of the support member 502 (see FIG. 10(b)).

[0070] The recording element substrate 228 includes a substrate 906 on which are formed a supply path 902 for supplying ink to pressure chambers 920 (described later) and a recovery path 904 for recovering ink from the pressure chambers 920 (see FIG. 9(b)). On one surface of the substrate 906, a nozzle forming member 910 is provided on which a nozzle row having a plurality of nozzles 802 for ejecting ink is formed. The substrate 906 is formed of, for example, silicon (Si), and the nozzle forming member 910 is formed of, for example, a photosensitive resin. In addition, on the other surface of the substrate 906 opposite to the one surface, a cover plate 912 is formed.

[0071] The supply path 902 and the recovery path 904 extend along the extension direction of the nozzle row in the nozzle forming member 910 (see FIG. 9(a)). The supply path 902 is disposed on one side of each nozzle row in the short side direction of the recording element substrate 228, and the recovery path 904 is disposed on the other side of each nozzle row in the short side direction. Furthermore, on one surface of the substrate 906, a plurality of supply ports 914 communicating with the supply path 902 are arranged along the extension direction of the nozzle row. Furthermore, on one surface of the substrate 906, a plurality of recovery ports 916 communicating with the recovery path 904 are arranged along the extension direction of the nozzle row.

[0072] On one side of the substrate 906, a recording element 918, which is a heat generating element (electrothermal conversion element) for causing the ink to bubble by thermal energy, is provided at a position facing the nozzle 802. That is, in this embodiment, the recording element 918 functions as an energy generating element that generates energy for ejecting ink from the nozzle. The recording element 918 is located in a pressure chamber 920 formed in the nozzle forming member 910. The pressure chamber 920 is formed for each recording element 918 by a partition wall 908. In addition, on one side of the substrate 906, a terminal 922 is provided that is electrically connected to the recording element 918 by an electric wiring (not shown) provided on the substrate 906. Therefore, the recording element 918 generates heat based on an ejection control signal input via the electric wiring board 304 and the flexible wiring board 302, and boils the ink in the pressure chamber 920. The ink in the pressure chamber 920 is ejected from the nozzle 802 by the force of the bubble generation caused by this boiling.

[0073] The cover plate 912 is provided with openings 804 that communicate with the supply path 902 and the recovery path 904. Ink is supplied to the supply path 902 from the openings 804 that communicate with the supply path 902, and ink flows out to the openings 804 that communicate with the recovery path 904. In this embodiment, three openings 804 are formed in each supply path 902, and two openings 804 are formed in each recovery path 904. The cover plate 912 also functions as a lid that forms part of the supply path 902 and the recovery path 904 formed in the substrate 906. The cover plate 912 is required to have sufficient corrosion resistance against the ink, and from the viewpoint of preventing color mixing, the opening shape and the opening position of the opening 804 are required to have high accuracy. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material of the cover plate 912, and to provide the openings 804 by a photolithography process. In this way, the cover plate 912 converts the pitch of the flow paths by the openings 804, and considering the pressure loss, it is preferable that the thickness is thin, and it is made of, for example, a film-like material.

[0074] In the recording element substrate 228, a driving switch 1002 for driving the recording element 918 and a selection circuit 1004 for selecting the recording element 918 are arranged between the recording element rows in which a plurality of recording elements 918 are arranged (see FIG. 10). In addition, a temperature inspection diode (not shown), a driving switch 1006 for driving the temperature control heating element 1204 (described later), and a selection circuit 1008 for selecting the temperature control heating element are arranged between the recording element rows. The driving switch 1002 and the selection circuit 1004 are circuits for driving the recording element located on one side (upper side in FIG. 10). In addition, a temperature inspection diode for detecting the temperature of the recording element substrate 228 is arranged between the recording element rows. Furthermore, the driving switch 1006 and the selection circuit 1008 are circuits for driving the temperature control heating element 1204 corresponding to the recording element located on the other side (lower side in FIG. 10).

[0075] In the recording element substrate 228, the supply path 902 is connected to the common supply flow path 230, and the recovery path 904 is connected to the common recovery flow path 232, so that a pressure difference occurs between the supply path 902 and the recovery path 904. During the ink circulation in the circulation path, this pressure difference causes ink to flow from the supply path 902 through the supply port 914, the pressure chamber 920, and the recovery port 916 toward the recovery path 904. This flow allows, for example, thickened ink, bubbles, foreign matter, etc., generated by evaporation from the nozzle 802 in the nozzle 802 or the pressure chamber 920 where printing is paused to flow out to the recovery path 904. In addition, the increase in the viscosity of the ink in the nozzle 802 or the pressure chamber 920 can be suppressed. The ink that flows out to the recovery path 904 is collected in the flow path member 416 through the opening 804 of the cover plate 912 and the communication port 504 of the support member 502.

[0076] Ink supplied to the recording head 14 flows through the joint rubber 408, the communication port 606 in the third flow path member 426, the common supply flow path 230, the communication port 608 in the second flow path member 424, and the individual supply flow path 234 in the first flow path member 422, and then flows into the communication port 612. Thereafter, the ink flows through the communication port 504 in the support member 502, the opening 804 in the cover plate 912, and the supply path 902 and supply port 914 provided in the substrate 906, and then flows into the pressure chamber 920.

[0077] Of the ink supplied to the pressure chamber 920, ink that has not been ejected from the nozzle 802 flows out to the recovery port 916 in the substrate 906, the recovery path 904, the opening 804 in the cover plate 912, and the communication port 504 in the support member 502. After that, the ink flows out through the communication port 612 in the first flow path member 422, the individual recovery flow path 236, the communication port 608 in the second flow path member 424, the common recovery flow path 232, and the communication port 606 in the third flow path member 426, and flows out to the joint rubber 408. Then, the ink flows out from the connection portion 310 provided in the supply unit 224 to the outside of the recording head 14.

[0078] In the first circulation path 200, the ink flowing in from the connection portion 310 passes through the negative pressure control unit 226 and is then supplied to the joint rubber 408. In the second circulation path 250, the ink collected from the pressure chamber 920 passes through the joint rubber 408 and then flows out of the recording head 14 from the connection portion 310 via the negative pressure control unit 226. In the circulation path of this embodiment, not all of the ink that flows into the common supply flow path 230 of the ejection unit 222 is supplied to the pressure chamber 920 via the individual supply flow path 234. Some ink flows out from the common supply flow path 230 to the supply unit 224 without flowing into the individual supply flow path 234. In this way, by providing a path that flows without passing through the recording element substrate 228, it is possible to suppress the backflow of the circulating flow of the ink even if a recording element substrate 228 having a fine flow path with a large flow resistance is used. Therefore, in the print head 14 according to this embodiment, thickening of the ink near the pressure chambers 920 and the nozzles 802 can be suppressed, and deviation from the normal ejection direction and ejection failures can be suppressed, making it possible to perform high-quality printing.

[0079] (Positional relationship between recording element substrates) Next, a description will be given of the positional relationship between adjacent recording element substrates 228 among the multiple recording element substrates 228 arranged in the extending direction of the recording head 14. Fig. 11 is a diagram showing the positional relationship between adjacent recording element substrates 228.

[0080] The recording element substrate 228 is formed in a substantially parallelogram shape (see FIG. 8(a)), and each of the nozzle rows 1102, 1104, 1106, 1108 is arranged so as to be inclined at a predetermined angle with respect to the transport direction of the recording medium M. In the corresponding nozzle rows of adjacent recording element substrates 228, one nozzle is arranged so as to overlap in the transport direction of the recording medium M (see dashed line D in FIG. 11). The number of nozzles overlapping in the transport direction is not limited to one, and may be multiple.

[0081] By arranging the adjacent recording element substrates 228 in this manner, even if the position of the recording element substrate 228 is slightly deviated from the predetermined position, black streaks and white spots occurring in the recorded image can be made difficult to see by driving control of the overlapping nozzles. The recording element substrates 228 can also be arranged in a straight line (inline) instead of in a staggered arrangement as shown in FIG. 11. Note that, in this embodiment, the recording element substrate 228 is formed into a substantially parallelogram shape, but is not limited to this, and may be, for example, a quadrilateral shape having long and short sides such as a rectangle or a trapezoid, or various other known shapes.

[0082] (Configuration of the vicinity of the heat application portion on the recording element substrate) Next, the configuration in the vicinity of the recording elements 918, which are the heat application parts in the recording element substrate 228, will be described. Fig. 12 is a diagram showing the configuration in the vicinity of the recording elements 918 in the recording element substrate 228. Fig. 12(a) is a diagram showing the configuration inside a pressure chamber 920. Fig. 12(b) is a diagram showing a part of the configuration laminated on one surface of a substrate 906 on which a nozzle forming member 910 is formed. Fig. 13 is a cross-sectional view taken along line XIII-XIII in Fig. 12(a).

[0083] <Layer structure on the substrate surface> In the recording element substrate 228, the substrate 906 on which the nozzle forming member 910 is laminated is formed by laminating components such as wiring and recording elements 918 on a base 1302 (see FIG. 13). In this embodiment, an insulating heat storage layer 1304 formed of a thermal oxide film, a SiO film, a SiN film, or the like is formed on the base 1302 (on the base). A plurality of wiring layers 1306, 1308, 1310, and 1312 (four layers in this embodiment) are formed on the heat storage layer 1304, and each wiring layer is connected by a heat transfer member. Each wiring layer is made of a metal material such as Al, Al-Si, or Al-Cu, and the heat transfer member is mainly made of tungsten, or the like.

[0084] The wiring layer 1310 includes a power supply (VH) wiring for driving the recording element 918, and the wiring layer 1312 is used as a GND (GNDH) wiring for VH. The wiring layer 1308 is a connection wiring mainly for driving logic, and the wiring layer 1306 is used as a power supply wiring for driving logic. For example, the wiring layer 1310 and the wiring layer 1312 are formed with the same film thickness, the wiring layer 1308 is formed with a film thickness smaller than the wiring layers 1310 and 1312, and the wiring layer 1306 is formed with a film thickness equal to or smaller than the wiring layer 1308. The wiring layers are insulated from each other by the heat storage layer 1304, and are electrically connected only by the heat transfer member.

[0085] A recording element 918 is disposed on the heat storage layer 1304. The recording element 918 is connected to the wiring layer 1312 via heat transfer members 1314a and 1314b. An insulating protective layer 1316 is disposed on the recording element 918 and the heat storage layer 1304. The insulating protective layer 1316 is an insulating layer that covers the recording element 918 and the heat storage layer 1304. The insulating protective layer 1316 is formed of a SiO film, a SiN film, or the like.

[0086] A protective layer 1318 for blocking contact with the ink in the pressure chamber 920 is provided on the insulating protective layer 1316. This protective layer 1318 includes a lower protective layer 1320, an upper protective layer 1322, and an adhesive protective layer 1324, and protects the surface of the recording element 918 from chemical and physical shocks associated with heat generation from the recording element 918. In this embodiment, the lower protective layer 1320 is made of tantalum (Ta), the upper protective layer 1322 is made of iridium (Ir), and the adhesive protective layer 1324 is made of tantalum (Ta). For this reason, the protective layer 1318 has electrical conductivity.

[0087] A protective layer 1326 is provided on the adhesive protective layer 1324 to improve ink resistance and adhesion to the nozzle forming member 910. The protective layer 1326 is preferably formed of a film that is difficult to dissolve in ink, such as SiCN / SiOC. In the protective layer 1318, the adhesive protective layer 1324 and the protective layer 1326 are not formed in most of the area above the recording element 918, and the upper protective layer 1322 is exposed inside the pressure chamber 920.

[0088] The upper protective layer 1322 is formed of a material that contains a metal that dissolves into the ink in the pressure chamber 920 by an electrochemical reaction, and does not form an oxide film that prevents the dissolution by heating. When ink is ejected from the nozzle 802, the ink in the pressure chamber 920 contacts the surface of the upper protective layer 1322, and cavitation occurs in which the temperature rises instantaneously on the surface by driving the recording element 918, causing the ink to foam and then disappear. For this reason, in this embodiment, the upper protective layer 1322 is formed of iridium, which is highly corrosion-resistant and highly reliable, so as to contact the ink on the recording element 918.

[0089] <Temperature detection element> A temperature detection element 1328 capable of detecting the temperature of the recording element 918 is provided near the recording element 918 and directly below the recording element 918. In the recording device 10, the temperature detection element 1328 detects a change in temperature of the recording element 918 when the recording element 918 is driven, and detects the presence or absence of ejection. A drive element 1202 (see FIG. 12(b)) for driving the temperature detection element 1328 is disposed between adjacent recording elements 918 in the recording element array.

[0090] <Heat dissipation wiring layer> A heat dissipation wiring layer 1330 for dissipating heat generated by the recording element 918 is formed directly below the temperature detection element 1328 (see FIG. 13). The heat dissipation wiring layer 1330 is formed by connecting the wiring layers 1306, 1308, 1310, and 1312 located directly below the temperature detection element 1328 with heat transfer members 1332, 1334, and 1336. Note that the members in each wiring layer constituting the heat dissipation wiring layer 1330 are insulated from, for example, the wiring in the corresponding wiring layer and connected to the base 1302, and therefore have the same potential as the base 1302 (mainly connected to GND). Furthermore, the heat dissipation wiring layer 1330 is connected to the base 1302 through a heat dissipation contact 1340 made of a heat transfer member in the wiring layer 1306 located closest to the base 1302 among the wiring layers. Although a base insulating layer (oxide film) 1338 is formed between the base 1302 and the heat storage layer 1304, the base insulating layer 1338 is not formed in the portion where the heat dissipation contact 1340 is connected to the base 1302. Heat generated in the recording element 918 is dissipated to the base 1302 via the heat dissipation wiring layer 1330 and the heat dissipation contact 1340. Thus, in this embodiment, the heat dissipation wiring layer 1330 is provided directly below the recording element 918, and the heat storage layer 1304 serves as an insulating layer, functioning as a heat transfer layer formed by laminating layers via the insulating layer.

[0091] <Temperature control heating element> The recording element substrate 228 is provided with temperature control heating elements 1204 capable of adjusting the temperature of the ink flowing therein and the recording element substrate 228 (see FIG. 12(b) and FIG. 13). Specifically, the temperature control heating elements 1204 are provided on both sides of the recording element array in which the recording elements 918 are arranged, extending along the arrangement direction of the recording element array (see FIG. 12(b)). When driven, the temperature control heating elements 1204 generate heat, and can raise the temperature of the ink flowing through the recording element substrate 228 to a desired temperature.

[0092] <Heat dissipation contact> The drive control resolution of the temperature control heat generating element 1204 is coarser than the drive control resolution of the recording element 918. That is, while the drive of each recording element 918 can be controlled, the temperature control heat generating element 1204 is divided into groups corresponding to a plurality of recording elements 918, and the drive is controlled for each group. For this reason, for example, if the temperature control heat generating element 1204 continues to be driven, there is a risk that the adjacent recording elements will be affected by heat more than necessary, and ink will not be ejected properly. In addition, the recording element substrate 228 allows the recording elements 918 to be driven at a high frequency. Furthermore, in the recording element substrate 228, the recording elements 918 are arranged at a high density (for example, 600 dpi or more). For this reason, there is a risk that the adjacent recording elements 918 will be affected by heat.

[0093] Therefore, in this embodiment, as the heat dissipation contact 1340, a heat dissipation contact 1340a is arranged between the temperature control heat generating element 1204 and the recording element 918 (see FIG. 12(b) and FIG. 13). Also, as the heat dissipation contact 1340, a heat dissipation contact 1340b is arranged between adjacent recording elements in the recording element array (see FIG. 12(b)). Note that the heat dissipation contact 1340b may be arranged closer to the temperature control heat generating element side where the heat dissipation contact 1340a is not provided between the recording element 918, or may be extended to the vicinity of the temperature control heat generating element 1204.

[0094] 13, the wiring layer 1306 extends to the rear or front side of the paper, and the wiring layer 1306 extending to the rear or front side and the base 1302 are connected by a heat dissipation contact 1340b at a position where there is no underlying insulating layer 1338. Also, the heat dissipation contact 1340a and the heat dissipation contact 1340b are each formed at a position that does not overlap with the recording element 918 in a plane that intersects (orthogonal in this embodiment) the lamination direction of each wiring layer (see FIG. 12(b)). In other words, the heat dissipation contacts 1340a and 1340b are disposed at a position that is not directly below the recording element 918.

[0095] In this manner, in this embodiment, by providing the heat dissipation contact 1340a between the recording element 918, which serves as a heat source, and the temperature control heat generating element 1204, not only the heat generated by the recording element but also the heat generated by the temperature control heat generating element located nearby can be dissipated to the base 1302. In addition, by providing the heat dissipation contact 1340b between adjacent recording elements 918, not only the heat of the recording element 918 connected by the heat dissipation wiring layer 1330 but also the heat of the adjacent recording elements 918 can be dissipated to the base 1302.

[0096] <Distance between each wiring layer and the supply port> In the pressure chamber 920, ink is supplied from the supply port 914 and collected in the recovery port 916. Therefore, when the ink circulates in the circulation path, the ink flows from the supply port 914 side to the recovery port 916 side. Since the ink may dissolve the interlayer insulating film, each wiring layer is provided at a certain distance from the supply port 914. This prevents the ink from shorting out with the wiring. The wiring layers 1310 and 1312 and the wiring layers 1306 and 1308 are different in distance from the supply port 914, and the wiring layers 1310 and 1312 (see distance X in FIG. 13) are closer than the wiring layers 1306 and 1308 (see distance Y in FIG. 13). This is to detect a VH leak that occurs with a high probability when the wiring layers 1310 and 1312 and the ink are shorted out at an early stage and prevent the printing device from failing.

[0097] <Infection Retardation Section> The heat transfer members 1314a and 1314b connected to the recording element 918 may be destroyed if excessive voltage or current is applied. In particular, the heat transfer member 1314a side (positive power supply side) to which the recording element power supply voltage VH is applied is often destroyed because current flows first. If the heat transfer member 1314a is destroyed, ink will come into contact with the destroyed heat transfer member 1314a, or, if the destruction is large, even the wiring layer 1312.

[0098] If ink comes into contact with the heat transfer member 1314a or the wiring layer 1312 due to the breakdown, the ink will corrode them because the printing element power supply voltage VH is applied to them. Eventually, the corrosion will reach the wiring layer 1310 that is commonly connected to all the printing elements 918, and a break in one printing element 918 may cause all the printing elements 918 to become unusable.

[0099] Therefore, in this embodiment, the recording element substrate 228 is provided with a transmission retardation portion 1342 for retarding the transmission of corrosion caused by ink to the wiring layer 1310 when the wiring to the recording element 918 is broken. The transmission retardation portion 1342 is configured so that corrosion of the wiring caused by ink that has entered from the broken portion passes from the wiring layer 1312 through each heat transfer member, once through the wiring layer 1308, and then is connected to the power wiring of the wiring layer 1310. That is, the recording element substrate 228 is connected to the wiring layer 1310, which is the power wiring, through the transmission retardation portion 1342 formed to make a detour in the stacking direction of each wiring layer.

[0100] Specifically, in the transmission delay section 1342, a heat transfer member 1314 connected to the recording element 918 is connected to a member 1313 of the wiring layer 1312. Furthermore, the member 1313 is connected to a member 1344 of the wiring layer 1310 via a heat transfer member 1346. Furthermore, the member 1344 is connected to a member 1309 of the wiring layer 1308 via a heat transfer member 1348. Furthermore, the member 1309 is connected to a wiring section (power supply wiring) 1347 connected to a power supply of the wiring layer 1310 via a heat transfer member 1350. Note that the members in each wiring layer constituting the transmission delay section 1342 are insulated from the wiring in the corresponding wiring layer. As a result, corrosion does not propagate directly from the member of the wiring layer 1312 to the wiring portion 1347, but travels from the member 1313 of the wiring layer 1312 via the member 1344 to a detour to the member 1309 of the wiring layer 1308, and then reaches the wiring portion 1347 of the wiring layer 1310. In this manner, in this embodiment, the transmission retardation portion 1342 is formed by laminating it on the base 1302 via the heat storage layer 1304, and functions as a heat transfer layer that connects the recording element 918 and the wiring layer 1310.

[0101] In the transmission retardation section 1342, the connection position between the members of each layer by the heat transfer member is located at or near the end of the member. The near end is, for example, within 5 μm from the end. This ensures the length of the path along which corrosion propagates, and increases the time it takes for the corrosion to reach the wiring layer 1310, thereby extending the life of the recording element substrate 228. With this configuration, even when a specific recording element breaks down, the specific recording element can be placed in a non-ejection (non-discharge) state, and the reliability line can be ensured, and the use can be continued. In this embodiment, the transmission retardation section 1342 is configured to be bypassed to the wiring layer 1308, but this is not limited to this. For example, the transmission retardation section 1342 may be bypassed to the wiring layer 1306. In this case, the transmission retardation section 1342 and the heat dissipation contact 1340 are arranged at positions where they do not interfere with each other.

[0102] <Prevents burning> The recording element substrate 228 is configured to be capable of suppressing kogation that accumulates on the upper protective layer 1322 due to driving of the recording elements 918. Kogation occurs when coloring materials and additives contained in ink are decomposed at a molecular level by being heated at high temperatures and turned into hardly soluble substances, and the substances are physically adsorbed on the surface of the upper protective layer 1322.

[0103] In the recording element substrate 228, in order to suppress kogation, the portion directly above the recording element 918 of the upper protective layer 1322 is used as an electrode 1210, and a counter electrode 1212 corresponding to the electrode 1210 is provided near the recovery port 916 (see FIG. 12(a)), so as to form an electric field within the pressure chamber 920. Note that the electrode 1210 functions as a negative electrode during recording operation. This makes it possible to move particles such as pigments in the ink that are negatively charged away from the surface of the electrode 1210, that is, the surface of the upper protective layer 1322 above the recording element 918.

[0104] In this way, by reducing the presence rate of negatively charged particles (hereinafter also referred to as "negatively charged particles") near the surface of the upper protective layer 1322, it is possible to suppress the accumulation of kogation during a recording operation on the surface of the upper protective layer 1322 on the recording element 918. That is, in the recording element substrate 228, when the upper protective layer 1322 is heated to a high temperature, the occurrence of kogation is suppressed by reducing the presence rate of coloring materials, additives, etc. that cause kogation near the surface of the upper protective layer 1322.

[0105] The mechanism of electric field control (potential control) during kogation suppression in this embodiment will be described with reference to Fig. 14. Fig. 14 is a diagram showing the electric field and negatively charged particles in a potential controlled state and in a non-potential controlled state. In a non-potential controlled state between the electrode 1210 and the counter electrode 1212, negatively charged particles 1402 in the ink are dispersed approximately uniformly in the ink in the pressure chamber 920, as shown in Fig. 14(a).

[0106] When a voltage is applied so that the potential of the electrode 1210 is relatively lower than the potential of the counter electrode 1212, the state becomes as shown in FIG. 14(b). At this time, the potential difference between the electrode 1210 and the counter electrode 1212 is about 0.5 to 2.5 V. At this time, an electric field 1404 is formed between the electrode 1210 and the counter electrode 1212 via the ink, but no current flows. Then, the electrode 1210 has a negative potential relative to the counter electrode 1212, so that the negative potential particles 1402 are repelled from the surface of the electrode 1210, and the presence rate of the negative potential particles 1402 in the vicinity of the surface of the electrode 1210 decreases. The negative potential particles 1402 are repelled by a repulsive force 1406 from the surface of the electrode 1210 along the electric field lines of the electric field 1404 formed in the ink (see FIG. 14(d)).

[0107] Due to this mechanism, in this embodiment, the larger the potential difference ΔV (=Vc-Vh) between the potential of the counter electrode 1212 and the potential of the electrode 1210, Vc, the more the negative potential particles 1402 that cause kogation are repelled from the electrode 1210, and kogation on the electrode 1210 becomes difficult. Kogation that adheres to the electrode 1210, that is, kogation that adheres near the surface of the upper protective layer 1322, is removed by applying a voltage between the electrode 1210 and the counter electrode 1212 to dissolve the surface part of the upper protective layer 1322 into ink and lifting off the kogation. At this time, a voltage of 3V or more that dissolves the electrode material iridium is applied between the electrode 1210 and the counter electrode 1212. At this time, it is preferable to apply the voltage to the electrode 1210 while determining the direction of the voltage. By removing the kogation in this way, the surface of the electrode 1210 becomes almost free of kogation.

[0108] If ink is ejected when there is almost no kogation on the upper protective layer 1322 after the kogation removal, noticeable kogation occurs on the upper protective layer 1322. As a result, the ejection characteristics change significantly within a certain period of time immediately after the kogation removal. For this reason, after the kogation removal, an aging process is performed to allow an appropriate amount of kogation to adhere to the upper protective layer 1322. In this case, the electric field is controlled so that negatively charged particles gather on the upper protective layer 1322, as shown in Figure 14(c).

[0109] (Action and effect) As described above, in the recording element substrate, the heat dissipation contacts for dissipating heat from the heat dissipation wiring layer provided directly below the temperature detection element to the substrate are provided between the temperature control detection element and the recording element and between adjacent recording elements. This makes it possible to perform pinpoint heat dissipation in areas where high heat dissipation efficiency is required. This makes it possible to reduce the area occupied by the heat dissipation contacts, which contributes to the miniaturization and high density of the recording element substrate.

[0110] In addition, in the recording element substrate, the recording elements are connected in a detour in the stacking direction of each wiring layer by the wiring section connected to the power supply and the transmission delay section. As a result, even if a break occurs between the recording element and the transmission delay section, the distance from the broken part to the wiring section becomes longer, and the time it takes for corrosion by ink to reach the wiring section becomes longer. Therefore, even if a specific recording element cannot eject ink due to the break, the ink from the nozzle corresponding to the recording element can be ejected from another nozzle, and the recording element substrate can be used continuously.

[0111] (Other embodiments) The above-described embodiment may be modified as shown in the following (1) to (5).

[0112] (1) In the above embodiment, the recording elements 918 and the heat dissipation contacts 1340a are arranged between the respective recording elements 918 and the temperature control heating elements 1204 in a one-to-one relationship, but this is not limited thereto. For example, one heat dissipation contact 1340a may be arranged for a plurality of recording elements 918. Although not specifically described in the above embodiment, the heat dissipation contacts 1340b corresponding to the recording elements 918 located at both ends of the recording element array are provided, for example, on the outside of the recording element array. Furthermore, in the above embodiment, the heat dissipation contacts 1340b are arranged between adjacent recording elements 918, and one heat dissipation contact 1340b corresponds to one recording element 918, but this is not limited thereto. For example, the heat dissipation contacts 1340b may be arranged alternately between adjacent recording elements 918. In this case, one heat dissipation contact 1340b corresponds to two recording elements 918.

[0113] (2) In the above embodiment, the exposed area of ​​the upper protective layer 1322 to the pressure chamber 920, i.e., the area of ​​the electrode 1210, is smaller than the area of ​​the upper surface of the recording element 918, but this is not limited to the above. For example, as shown in Fig. 15, the electrode 1210 may be exposed to the pressure chamber 920 in an area larger than the area of ​​the upper surface of the recording element 918, i.e., the area that contributes to the bubbling of the ink. For example, when the size of the recording element 918 is 15 µm x 20 µm, the electrode 1210 is 19 µm x 24 µm and is formed with chamfered corners.

[0114] (3) Although not specifically described in the above embodiment, in the process of removing kogation, the voltage applied between the electrode 1210 and the counter electrode 1212 may be reversed, so that not only the electrode 1210 but also the counter electrode 1212 dissolves and decreases. The counter electrode 1212 is disposed in the vicinity of the recovery port 916, for example, with a size of 20 μm×20 μm, so as not to come into contact with the components used for ejecting ink from the nozzles, such as the recording element 918. Although not specifically described in the above embodiment, the temperature control heating element 1204 is made of, for example, POL (polysilicon) or AL (aluminum). The temperature control heating element 1204 may have the same configuration as the recording element 918.

[0115] (4) The above embodiment is not limited to a recording device that discharges ink to record on a recording medium, but can be applied to various liquid discharge devices that discharge liquid to obtain a product. In the above embodiment, the recording device 10 is a so-called full-line type recording device that uses a long recording head that covers the entire width of the recording area on the recording medium, but is not limited to this. It may also be a so-called serial scan type recording device that uses a recording head that discharges ink while moving in a direction intersecting the transport direction of the recording medium.

[0116] (5) The above embodiment and the various configurations shown in (1) to (4) above may be combined as appropriate.

[0117] The disclosure of the above embodiment includes the following configurations and methods. (Configuration 1) A liquid ejection head substrate capable of ejecting liquid by energy generated by an energy generating element, A substrate; a first heat transfer layer provided directly below the energy generating element and formed by laminating on the base via an insulating layer; a temperature control heating element capable of controlling temperatures of the liquid and the liquid ejection head substrate; a first heat transfer member connecting the first heat transfer layer and the base, The substrate for a liquid ejection head, wherein the first heat transfer member is provided between adjacent ones of the energy generating elements and between the energy generating elements and the temperature control heating elements. (Configuration 2) 2. The substrate for a liquid ejection head according to configuration 1, wherein the first heat transfer member does not overlap the energy generating element in a plane intersecting with a lamination direction of the first heat transfer layer. (Configuration 3) 3. The liquid ejection head substrate according to configuration 1 or 2, further comprising a temperature detection element between the energy generating element and the first heat transfer layer, the temperature detection element being capable of detecting a temperature of the energy generating element. (Configuration 4) A second heat transfer layer is laminated on the base via the insulating layer and connects the energy generating element and a power supply line, The liquid ejection head substrate according to any one of configurations 1 to 3, wherein the second heat transfer layer makes a detour in a lamination direction of the second heat transfer layer to connect the energy generating element and the power supply wiring. (Configuration 5) The second heat transfer layer is connected between layers by a second heat transfer member, 5. The liquid ejection head substrate according to configuration 4, wherein the second heat transfer member connects the layers at or near an end in a plane intersecting the stacking direction. (Configuration 6) 6. The liquid ejection head substrate according to configuration 5, wherein the second heat transfer member connects the layers at a position within 5 μm from the end portion. (Configuration 7) A plurality of the energy generating elements are arranged in a predetermined direction, The temperature control heating elements are provided on both sides of the arranged energy generating elements along the predetermined direction, 7. The liquid ejection head substrate according to any one of configurations 1 to 6, wherein a drive control resolution of the temperature control heat generating elements is coarser than a drive control resolution of the energy generating elements. (Configuration 8) 8. The liquid ejection head substrate according to configuration 7, wherein the drive elements for driving the temperature control heat generating elements are disposed between adjacent energy generating elements. (Configuration 9) The substrate for a liquid ejection head according to configuration 7 or 8, wherein the first heat transfer member is provided between the temperature control heat generating element and the energy generating element provided on one side of the arranged energy generating elements, and between adjacent energy generating elements. (Configuration 10) A substrate for a liquid ejection head as described in configuration 9, wherein the first heat transfer member provided between adjacent energy generating elements extends to the vicinity of the temperature control heat generating element provided on the other side of the arranged energy generating elements, or is provided closer to the temperature control heat generating element provided on the other side of the arranged energy generating elements. (Configuration 11) 10. The liquid ejection head substrate according to configuration 9, wherein one of the first heat transfer members is provided for one of the energy generating elements on one side of the arranged energy generating elements. (Configuration 12) 10. The liquid ejection head substrate according to configuration 9, wherein one of the first heat transfer members is provided for a plurality of the energy generating elements on one side of the arranged energy generating elements. (Configuration 13) 11. The liquid ejection head substrate according to configuration 10, wherein one first heat transfer member is provided for one energy generating element between adjacent energy generating elements. (Configuration 14) 11. The liquid ejection head substrate according to configuration 10, wherein one first heat transfer member is provided for two of the energy generating elements between adjacent ones of the energy generating elements. (Configuration 15) 15. A liquid ejection head comprising the liquid ejection head substrate according to any one of configurations 1 to 14. (Configuration 16) 16. The liquid ejection head according to configuration 15, wherein the substrate for the liquid ejection head is a rectangle having long sides and short sides. (Configuration 17) 17. The liquid ejection head according to configuration 15 or 16, wherein a plurality of the liquid ejection head substrates are arranged in a predetermined direction. (Configuration 18) A liquid ejection device having the liquid ejection head according to any one of configurations 1 to 17. (Configuration 19) 19. The liquid ejection apparatus according to configuration 18, further comprising a circulation path capable of circulating the liquid while supplying the liquid to the liquid ejection head substrate and recovering the liquid from the liquid ejection head substrate. [Explanation of symbols]

[0118] 228 Recording element board 918 Recording element 1204 Temperature control heating element 1302 Base 1330 Heat dissipation wiring layer 1340 Heat dissipation contact

Claims

1. A liquid ejection head substrate capable of ejecting liquid by energy generated by an energy generating element, A substrate; a first heat transfer layer provided directly below the energy generating element and laminated on the base via an insulating layer; a temperature control heating element capable of controlling temperatures of the liquid and the liquid ejection head substrate; a first heat transfer member connecting the first heat transfer layer and the base, The liquid ejection head substrate, wherein the first heat transfer member is provided between adjacent ones of the energy generating elements and between the energy generating elements and the temperature control heating elements.

2. The liquid ejection head substrate according to claim 1 , wherein the first heat transfer member does not overlap the energy generating element in a plane intersecting with a lamination direction of the first heat transfer layer.

3. 2. The liquid ejection head substrate according to claim 1, further comprising a temperature detection element between the energy generating element and the first heat transfer layer, the temperature detection element being capable of detecting a temperature of the energy generating element.

4. a second heat transfer layer that is laminated on the base via the insulating layer and connects the energy generating element and a power supply wiring; The liquid ejection head substrate according to claim 1 , wherein the second heat transfer layer makes a detour in a lamination direction of the second heat transfer layer to connect the energy generating elements and the power supply wiring.

5. The second heat transfer layer is connected between layers by a second heat transfer member, The liquid ejection head substrate according to claim 4 , wherein the second heat transfer member connects the layers at or near an end of a plane intersecting the stacking direction.

6. The liquid ejection head substrate according to claim 5 , wherein the second heat transfer member connects the layers at a position within 5 μm from the end portion.

7. A plurality of the energy generating elements are arranged in a predetermined direction, The temperature control heating elements are provided on both sides of the arranged energy generating elements along the predetermined direction, 2. The liquid ejection head substrate according to claim 1, wherein the drive control resolution of the temperature control heat generating elements is coarser than the drive control resolution of the energy generating elements.

8. 8. The liquid ejection head substrate according to claim 7, wherein a driving element for driving the temperature control heat generating element is disposed between adjacent energy generating elements.

9. The substrate for a liquid ejection head according to claim 7, wherein the first heat transfer member is provided between the temperature control heat generating element and the energy generating element provided on one side of the arranged energy generating elements, and between adjacent energy generating elements.

10. The substrate for a liquid ejection head according to claim 9, wherein the first heat transfer member provided between adjacent energy generating elements extends to the vicinity of the temperature control heat generating element provided on the other side of the arranged energy generating elements, or is provided closer to the temperature control heat generating element provided on the other side of the arranged energy generating elements.

11. The liquid ejection head substrate according to claim 9 , wherein one of the first heat transfer members is provided for one of the energy generating elements on one side of the arranged energy generating elements.

12. The liquid ejection head substrate according to claim 9 , wherein one of the first heat transfer members is provided for a plurality of the energy generating elements on one side of the arranged energy generating elements.

13. The substrate for a liquid ejection head according to claim 10 , wherein one first heat transfer member is provided for one energy generating element between adjacent ones of the energy generating elements.

14. The liquid ejection head substrate according to claim 10 , wherein one first heat transfer member is provided for two of the energy generating elements between adjacent ones of the energy generating elements.

15. A liquid ejection head comprising the liquid ejection head substrate according to claim 1 .

16. 16. The liquid ejection head according to claim 15, wherein the liquid ejection head substrate is in a rectangular shape having long sides and short sides.

17. 16. The liquid ejection head according to claim 15, wherein a plurality of the liquid ejection head substrates are arranged in a predetermined direction.

18. A liquid ejection device having a liquid ejection head comprising the liquid ejection head substrate according to claim 1 .

19. 20. The liquid ejection apparatus according to claim 18, further comprising a circulation path capable of circulating the liquid while supplying the liquid to the liquid ejection head substrate and recovering the liquid from the liquid ejection head substrate.

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