Liquid ejection head substrate, liquid ejection head, and liquid ejection device

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 substrate for a liquid ejection head, a liquid ejection head, and a liquid ejection apparatus. [Background technology]

[0002] In a recording element substrate mounted on a print head that ejects ink using an inkjet system, 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 functionality of recording element substrates, for example, temperature detection elements for detecting the temperature of the recording elements when they are driven, temperature control heating elements for adjusting the temperature of the ink and the recording element substrate, and the number of recording elements mounted on the recording element substrate have been installed.

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

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-198936 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 heat generation elements, etc., and it has been difficult to obtain a sufficient heat dissipation effect with a highly functional recording element substrate equipped with these elements.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a technique that enables efficient heat dissipation in a recording element substrate that has temperature-controllable heat-generating elements mounted thereon. [Means for solving the problem]

[0007] In order to achieve the above 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 body, a first heat transfer layer provided directly below the energy generating element and formed by laminating on the base body with an insulating layer interposed therebetween, 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 to the base body, 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. [Effects of the Invention]

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

[0009] [Figure 1] FIG. 1 is a schematic diagram of a recording apparatus. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 3 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 printing element substrate. [Figure 11] FIG. 3 is a diagram for explaining the arrangement of adjacent printing element substrates. [Figure 12] FIG. [Figure 13] FIG. [Figure 14] 5A and 5B are diagrams illustrating the behavior of negatively charged particles in a pressure chamber. [Figure 15] FIG. 10 is a diagram showing a modified example of an electrode. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, with reference to the accompanying drawings, 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. 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 necessarily essential to the solution of the present invention. Furthermore, the positions, shapes, etc. of the components described in the present embodiment are merely examples, and are not intended to limit the scope of the present invention to those alone.

[0011] In this specification, a liquid ejection device configured to eject liquid using a liquid ejection head equipped with a liquid ejection head substrate will be described as an example of a recording device configured to eject ink using a recording head equipped with a recording element 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 multiple recording media M continuously or intermittently. Note that the recording media M are not limited to cut sheets, and may also be continuous roll paper.

[0013] The recording head 14 is a line-type recording head that extends 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, collects the ink supplied to the recording head 14, and has a circulation path that can circulate the ink to be supplied to the recording head 14. In this embodiment, two circulation paths can be formed. The two circulation paths that can be applied to this embodiment will be described in detail below.

[0016] <First circulation route> First, a first circulation path will be described as one form of a circulation path applicable to the recording apparatus 10 according to this embodiment. Fig. 2(a) is a diagram showing a first circulation path as one form of a circulation path applicable to the recording apparatus 10 according to this embodiment. Note that Fig. 2(a) shows a circulation path for one ink. Since the recording apparatus 10 is configured to be able to eject four different inks, a 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 by driving the pump 212, ink stored in the buffer tank 204 is supplied to the recording head 14. 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 connects the inside with 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 ejected (discharged) from the nozzles of the recording head 14, for example, when ink contributing to recording is ejected and when ink not contributing to recording is ejected.

[0019] The pumps 214 and 216 are preferably positive displacement pumps having a constant liquid delivery capacity. Specific examples of 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, for example, arranging a general constant flow valve or relief valve at the pump outlet. Furthermore, the flow path 208 provided with the pump 214 is connected to a common supply flow path 230 (described later) in the recording head 14, and the flow path 210 provided with the pump 216 is connected to a common recovery flow path 232 (described later) in the recording head 14.

[0020] When the recording head 14 is driven, the pumps 214 and 216 suck a fixed amount of ink from the common supply flow path 230 and the common recovery flow path 232. 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 the flow rate is set too high, the negative pressure difference between the recording element substrates 228 will become too large due to the influence of pressure loss in the flow paths within the ejection unit 222, resulting in uneven density in 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 that flows out from the discharge unit 222.

[0022] The supply unit 224 supplies the ink supplied via the flow path 206 to the discharge unit 222 via the negative pressure control unit 226. Even when the flow rate in the circulation path fluctuates due to a change in the print duty during printing, the negative pressure control unit 226 operates to keep the pressure fluctuation downstream of the negative pressure control unit 226 (i.e., the discharge unit 222 side) within a certain range. The pressure fluctuation is kept within a certain range, for example, centered around 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 mechanisms 226a and 226b within a certain range of fluctuations centered around a desired set pressure. Of the negative pressure adjustment mechanisms 226a and 226b, the negative pressure adjustment mechanism 226a, which is set to a relatively high pressure, 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, which is set to a relatively low pressure, is connected to the common recovery flow path 232 of the discharge unit 222 via the supply unit 224.

[0024] An example of the negative pressure adjustment mechanisms 226a, 226b is a configuration similar to a so-called pressure reducing regulator. 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. This configuration can suppress the influence of the head difference between the buffer tank 204 and the print head 14, and can increase the degree of freedom in the layout of the buffer tank 204 of the printing apparatus 10.

[0025] The pump 212 may be any pump having a head pressure equal to or greater than a certain pressure within the range of the ink circulation flow rate used when driving the recording head 14, such as a turbo pump or a positive displacement pump. Specifically, a diaphragm pump or the like may be used as the pump 212. Also, instead of the pump 212, for example, a head tank disposed with a certain head difference relative 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, the ejection unit 222 is provided with 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, 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 channel 230 and the common recovery channel 232 are in communication with each other via the individual supply channels 234, the recording element substrate 228, and the individual recovery channels 236. The common supply channel 230 is connected to the negative pressure adjustment mechanism 226a and maintained at a relatively high pressure, while the common recovery channel 232 is connected to the negative pressure adjustment mechanism 226b and maintained at a relatively low pressure, creating a pressure difference between the two channels. As a result, some of the ink supplied to the common supply channel 230 flows into the common recovery channel 232 via the individual supply channels 234, the recording element substrate 228, and the individual recovery channels 236.

[0028] With this configuration, in the ejection unit 222, ink flows through the common supply flow path 230 and the common recovery flow path 232, while a portion of the ink passes through each recording element substrate 228. As a result, 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. Furthermore, during recording with 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 thickening of the ink in the nozzles and pressure chambers, and to discharge thickened ink and foreign matter in the ink from 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 will be described as one form of a circulation path applicable to the recording apparatus 10 according to this embodiment. FIG. 2(b) is a diagram showing a second circulation path as one form of a circulation path applicable to the recording apparatus 10 according to this embodiment. Note that FIG. 2(b) shows a circulation path for one ink. Since the recording apparatus 10 is configured to be able to eject four different inks, a 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. Furthermore, 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 that constitute the negative pressure control unit 226 each have a mechanism (a mechanism that functions in the same way 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 to keep the pressure fluctuations on its upstream side (i.e., on the ejection unit 222 side) within a certain range, even if the flow rate fluctuates due to changes in the printing duty during printing by the print head 14. The pressure fluctuations are kept within a certain range, for example, centered around a preset pressure. It is preferable that the pump 212 pressurize the downstream side of the negative pressure control unit 226 via the supply unit 224. This pressurization can suppress the effect of the head pressure of the buffer tank 204 on the print head 14. This increases the degree of freedom in the layout of the buffer tank 204 in the printing apparatus 10. Instead of the pump 212, for example, a head tank arranged with a predetermined head difference relative to the negative pressure control unit 226 may be used.

[0032] Similar 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, each set to a different control pressure. Of the two negative pressure adjustment mechanisms 226a and 226b, the negative pressure adjustment mechanism 226a, which is set to a relatively higher 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 to a relatively lower 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 in the common supply flow path 230 higher than the pressure in the common recovery flow path 232. Therefore, some 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 path 236.

[0033] With this configuration, the second circulation path 250 generates an ink flow in the ejection unit 222 similar to that of the first circulation path 200, but has two advantages different from the first circulation path 200. The first advantage is that, with the second circulation path 250, the negative pressure control unit 226 is disposed downstream of the print head 14, so 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 with 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 with 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 when circulating 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 within the discharge unit 222 within a desired range when adjusting the temperature of the print head 14 during standby for recording. Furthermore, 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, and therefore 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 total set flow rates of the pumps 214, 216, that is, the maximum amount of ink required, is the larger of A and F.

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

[0037] The first circulation path 200 also has advantages. Specifically, in the second circulation path 250, the flow rate through the discharge unit 222 is maximized during standby for printing. Therefore, the lower the printing duty, the higher the negative pressure applied to each nozzle. Therefore, 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 and the head width (the length of the short side of the print head 14) is reduced, high negative pressure is applied to the nozzles in low-duty images where unevenness is easily visible. Such high negative pressure application may increase the impact of satellite droplets. On the other hand, in the first circulation path 200, high negative pressure is applied to the nozzles during high-duty image formation. Therefore, even if satellite droplets are generated, they are less visible and have less impact on the printed image. Therefore, the printing device 10 selects a preferred circulation path in consideration of the specifications of the print head 14 and the printing device 10 (such as the discharge flow rate F, the minimum circulation flow rate A, and the flow path resistance within the print head).

[0038] (recording head) Next, the configuration of the recording head 14 will be described. Figure 3 is a perspective view of the recording head 14, where (a) is a view from below on one side in the transport direction, and (b) is a view from above on the other side in the transport direction. Figure 4 is an exploded view 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 has 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 electrical 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 electrical control unit (not shown) of the recording device 10. Each recording element substrate 228 is supplied with an ejection control signal from the electrical control unit via the signal input terminal 306, and is supplied with power required for ejection from the electrical control unit via the power supply terminal 308.

[0041] By consolidating the wiring using the electrical circuit on the electrical 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 portions 310 near both ends in the extension direction that are connected to the flow paths in the circulation paths. Ink is supplied to the recording head 14 from the flow paths in the circulation paths provided for each type of ink via the corresponding connection portions 310. Ink also flows out of the recording head 14 to the flow paths in the circulation paths provided for each type of ink via the corresponding connection portions 310.

[0043] The print head 14 includes a housing 402 to which a supply unit 224 and an electric wiring board 304 are attached (see FIG. 4). The supply unit 224 is provided with a connection portion 310. The supply unit 224 is provided with a filter 240 (see FIGS. 2(a) and 2(b)) inside for removing foreign matter from the ink being supplied. In this embodiment, the print head 14 includes two supply units 224, each of which is provided with flow paths and filters 240 for two colors. 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 by the action of valves, spring members, etc. provided inside, it significantly attenuates changes in pressure loss in the circulation path that occur with fluctuations in the ink flow rate. For this reason, the two negative pressure adjustment mechanisms 226a and 226b are set to different control pressures, and the high-pressure side negative pressure adjustment mechanism 226a is connected to the common supply flow path 230 of the ejection unit 222, and the low-pressure side negative pressure adjustment mechanism 226b is connected to the common recovery flow path 232 of the ejection unit 222.

[0045] The housing 402 includes a discharge unit support portion 404 that supports the discharge unit 222 and an electric wiring board support portion 406 that supports the electric wiring board 304, thereby ensuring the rigidity of the print head 14. The electric wiring board support portion 406 is fixed to the discharge unit support portion 404 with screws. The discharge unit support portion 404 corrects warping and deformation of the discharge unit 222 to ensure the relative positional accuracy of the multiple print element substrates 228. This reduces streaks and unevenness in the printed image due to the relative positional accuracy. Therefore, the discharge unit support portion 404 preferably has sufficient rigidity and is preferably made of a metal material such as SUS (stainless used steel) or aluminum, or a ceramic material such as alumina. The discharge unit support portion 404 also has openings 410 and 412 through which a joint rubber 408 is inserted. Ink supplied from the supply unit 224 is guided to a third flow path member 426 (described below) of the discharge unit 222 via 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 part 404 with screws, which prevents the flow path member 416 from warping or deforming.

[0048] The cover member 418 is a member having a frame-shaped surface in which an opening 420 is provided, which extends long in the extension direction of the recording head 14. The recording element substrate 228 and a sealant 510 (described later) of each discharge 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) that protects the recording head 14 when in 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 any irregularities or gaps on the surface where the recording element substrate 228 of the discharge unit 222 is exposed, so that a closed space is formed between the cap member and this surface when capping is performed.

[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 board 302 that electrically connects the recording element substrate 228 and an electric wiring board 304, and a support member 502 that supports the recording element substrate 228 and one end side of the flexible wiring board 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 so that the openings 804 of the recording element substrate 228 communicate with the communication openings 504. Furthermore, 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 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] Terminals 512 are provided on the other end side of the flexible wiring board 302, and the terminals 512 are electrically connected to connection terminals 428 (see FIG. 4) of the electrical wiring board 304. The support member 502 is a support 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 high flatness and can be bonded 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 configurations 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 the surface on which the discharge module 414 is disposed, and FIG. 6(b) is a diagram showing the other surface 422b of the first flow path member 422, which is the surface that joins with 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 the surface that joins with one surface 426a of the third flow path member 426. Figure 6(e) is a diagram showing one surface 426a of the third flow path member 426, and Figure 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 path grooves 602 are formed on the other surface 424b of the second flow path member 424 along the extension direction of the second flow path member 424 (see FIG. 6(d)). Furthermore, a common flow path groove 604 is formed on one surface 426a of the third flow path member 426 (see FIG. 6(e)). The common flow path grooves 604 are provided at positions corresponding to the respective common flow path grooves 602 provided on the other surface 424b when the one surface 426a of the third flow path member 426 is joined to the other surface 424b of the second flow path member 424, and the number of the common flow path grooves 604 corresponds to the respective common flow path grooves 602. As a result, when the second flow path member 424 and the third flow path member 426 are joined, the common flow path grooves 602 and the common flow path grooves 604 form eight common flow paths. These common flow paths become the common supply flow path 230 and the common recovery flow path 232 formed for each ink (see FIG. 7).

[0056] The third flow path member 426 is provided with communication openings 606 that penetrate 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 end portions 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 flow paths (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 that penetrate 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 individual flow path grooves 610 on the other surface 422b, which are inclined with respect to the short-side direction of the first flow path member 422 (a direction perpendicular to the extending direction of the first flow path member 422) (see FIG. 6(b)). The first flow path member 422 is also provided with communication openings 612 that penetrate from one surface 422a to the other surface 422b (see FIGS. 6(a) and 6(b)). The communication openings 612 are located in an area that is located in the center of the short-side direction of the first flow path member 422. The communication openings 612 are also located at positions that allow the communication openings 612 to be fluidly connected to the recording element substrate 228 via the communication openings 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 openings 612 are also located at one end of the individual flow path grooves 610. The individual flow channel 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 such materials include composite materials (resin materials) made of alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), or PSF (polysulfone) as a base material to which inorganic fillers such as silica particles or 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 together. Note that 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. Figure 7 shows the flow paths formed in the flow path member 416, with (a) being a partially enlarged view and (b) being a cross-sectional view taken along line VIIb-VIIb in (a). Note that Figure 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 arranged 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 that extend 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. Furthermore, 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 located in the center of the flow path member 416 via the individual supply flow path 234, and the common recovery flow path 232 can be fluidly connected to the recording element substrate 228 located in the center of the flow path member 416 via the individual recovery flow path 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, as will be described later, the recording element 918 and the nozzle 802 are arranged in the pressure chamber 920.

[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, within the print head 14, a portion of the ink supplied for each ink flows in the order of the common supply flow path 230, individual supply flow path 234, printing element substrate 228, individual recovery flow path 236, and common recovery flow path 232.

[0068] (Flow path configuration in 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 from the nozzle forming surface on which nozzles are formed, and (b) is a view 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 area within 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 within 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 formed 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 supply paths 902 that supply ink to pressure chambers 920 (described later) and recovery paths 904 that recover ink from the pressure chambers 920 (see FIG. 9(b)). On one surface of this substrate 906 is provided a nozzle forming member 910 on which is formed a nozzle array consisting of a plurality of nozzles 802 for ejecting ink. The substrate 906 is made of, for example, silicon (Si), and the nozzle forming member 910 is made of, for example, a photosensitive resin. A cover plate 912 is formed on the other surface of the substrate 906 that faces the one surface.

[0071] The supply path 902 and the recovery path 904 extend along the extension direction of the nozzle array in the nozzle forming member 910 (see FIG. 9(a)). The supply path 902 is arranged on one side of each nozzle array in the short direction of the recording element substrate 228, and the recovery path 904 is arranged on the other side of each nozzle array in the short 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 array. 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 array.

[0072] On one surface of the substrate 906, at a position facing the nozzle 802, there is provided a recording element 918, which is a heat generating element (electrothermal conversion element) for causing ink to bubble with thermal energy. 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 within 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 surface of the substrate 906, there is provided a terminal 922 that is electrically connected to the recording element 918 by electrical wiring (not shown) provided on the substrate 906. Therefore, the recording element 918 generates heat based on an ejection control signal input via the electrical wiring substrate 304 and the flexible wiring substrate 302, thereby boiling the ink in the pressure chamber 920. The bubbling force caused by this boiling causes the ink in the pressure chamber 920 to be ejected from the nozzle 802.

[0073] The cover plate 912 has openings 804 that communicate with the supply channels 902 and the recovery channels 904. Ink is supplied to the supply channels 902 through the openings 804 that communicate with the supply channels 902, and ink flows out of the recovery channels 904 through the openings 804 that communicate with the supply channels 902. In this embodiment, three openings 804 are formed in each supply channel 902, and two openings 804 are formed in each recovery channel 904. The cover plate 912 also functions as a lid that forms part of the supply channels 902 and the recovery channels 904 that are formed in the substrate 906. The cover plate 912 is required to have sufficient corrosion resistance against ink, and the opening shape and position of the openings 804 must be highly accurate to prevent color mixing. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material for the cover plate 912, and to form the openings 804 using 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 cover plate 912 is thin, and is made of, for example, a film-like material.

[0074] On the print element substrate 228, drive switches 1002 for driving the print elements 918 and selection circuits 1004 for selecting the print elements 918 are arranged between print element arrays in which multiple print elements 918 are arranged (see FIG. 10). Also arranged between the print element arrays are temperature detection diodes (not shown), drive switches 1006 for driving temperature control heat generating elements 1204 (described later), and selection circuits 1008 for selecting the temperature control heat generating elements. The drive switches 1002 and selection circuits 1004 function as circuits for driving print elements located on one side (the upper side in FIG. 10). Also, temperature detection diodes for detecting the temperature of the print element substrate 228 are arranged between the print element arrays. Furthermore, the drive switches 1006 and selection circuits 1008 function as circuits for driving the temperature control heat generating elements 1204 corresponding to print elements located on the other side (the lower side in FIG. 10).

[0075] In the recording element substrate 228, the supply channel 902 is connected to the common supply channel 230, and the recovery channel 904 is connected to the common recovery channel 232, so a pressure difference occurs between the supply channel 902 and the recovery channel 904. While the ink is circulating in the circulation channel, this pressure difference causes ink to flow from the supply channel 902 through the supply port 914, the pressure chamber 920, and the recovery port 916 toward the recovery channel 904. This flow allows, for example, thickened ink, bubbles, foreign matter, etc., generated by evaporation from the nozzles 802 in the nozzles 802 or pressure chambers 920 that are not performing printing to flow out into the recovery channel 904. This also makes it possible to suppress the increase in viscosity of the ink in the nozzles 802 or pressure chambers 920. The ink that flows out into the recovery channel 904 is recovered into the flow channel member 416 via the opening 804 in the cover plate 912 and the communication port 504 in 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, before flowing 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, before flowing into the pressure chamber 920.

[0077] Of the ink supplied to the pressure chambers 920, the ink that is not ejected from the nozzles 802 flows out through 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. Thereafter, 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 into the joint rubber 408. The ink then flows out of the recording head 14 from the connection portion 310 provided in the supply unit 224.

[0078] In the first circulation path 200, 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, ink collected from the pressure chamber 920 passes through the joint rubber 408 and then flows out of the print 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 paths 234. Some ink flows out of the common supply flow path 230 to the supply unit 224 without flowing into the individual supply flow paths 234. In this way, by providing a flow path that does not pass through the printing element substrate 228, it is possible to suppress backflow of the circulating flow of ink, even when a printing element substrate 228 is used that has fine flow paths with high flow resistance. Therefore, in the print head 14 according to this embodiment, the increase in viscosity of ink near the pressure chambers 920 and the nozzles 802 can be suppressed, and deviation of the ejection direction from the normal direction and ejection failures can be suppressed, enabling 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 extension direction of the recording head 14. Figure 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 dotted 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 adjacent recording element substrates 228 in this manner, even if the positions of the recording element substrates 228 are slightly deviated from the predetermined positions, drive control of the overlapping nozzles can make black streaks or white voids that appear in the recorded image less visible. The recording element substrates 228 can also be arranged in a straight line (inline) rather than in a staggered arrangement, as shown in FIG. 11. While the recording element substrates 228 are formed in a substantially parallelogram shape in this embodiment, the present invention is not limited to this, and may be formed in a quadrilateral shape with long and short sides, such as a rectangle or a trapezoid, or in any of 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 thermal action 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 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, SiO film, SiN film, or the like is formed on the base 1302 (on the base). Multiple (four in this embodiment) wiring layers 1306, 1308, 1310, and 1312 are formed on the heat storage layer 1304, and the respective wiring layers are 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 elements 918, and the wiring layer 1312 is used as a GND (GNDH) wiring for VH. The wiring layer 1308 is mainly a connection wiring for driving logic, and the wiring layer 1306 is used as a power supply wiring for driving logic. For example, the wiring layers 1310 and 1312 are formed to the same film thickness, the wiring layer 1308 is formed to a film thickness smaller than the wiring layers 1310 and 1312, and the wiring layer 1306 is formed to 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 an SiO film, a SiN film, or the like.

[0086] A protective layer 1318 is provided on the insulating protective layer 1316 to block contact with the ink inside the pressure chamber 920. 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 caused by 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). Therefore, the protective layer 1318 is electrically conductive.

[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 from 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 over most of 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 from a material that contains a metal that dissolves into the ink in the pressure chambers 920 through an electrochemical reaction, and that does not form an oxide film that prevents this dissolution when heated. When ink is ejected from the nozzles 802, the ink in the pressure chambers 920 comes into contact with the surface of the upper protective layer 1322, and when the recording elements 918 are driven, the temperature on this surface rises instantaneously, causing cavitation, in which the ink foams and then disappears. For this reason, in this embodiment, the upper protective layer 1322 is formed from iridium, which is highly corrosion-resistant and reliable, so that it comes into contact with the ink on the recording elements 918.

[0089] <Temperature detection element> A temperature detection element 1328 capable of detecting the temperature of the printing element 918 is provided near and directly below the printing element 918. In the printing apparatus 10, the temperature detection element 1328 detects the temperature change of the printing element 918 when the printing 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 printing elements 918 in the printing 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 wiring layers 1306, 1308, 1310, and 1312 located directly below the temperature detection element 1328 via 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 via 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 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. As described above, 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 with the insulating layer interposed therebetween.

[0091] <Temperature control heating element> The recording element substrate 228 is provided with temperature control heating elements 1204 that can adjust the temperature of the ink flowing therein and the recording element substrate 228 (see FIGS. 12(b) and 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 direction of arrangement 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 level.

[0092] <Heat dissipation contact> The drive control resolution of the temperature-controlled heat generating elements 1204 is coarser than the drive control resolution of the print elements 918. That is, while the print elements 918 can be individually controlled, the temperature-controlled heat generating elements 1204 are divided into groups corresponding to multiple print elements 918, and their drive is controlled on a group-by-group basis. For this reason, for example, if the temperature-controlled heat generating elements 1204 are continuously driven, there is a risk that the heat will have an excessive effect on adjacent print elements, preventing ink from being ejected properly. Furthermore, the print element substrate 228 allows the print elements 918 to be driven at a high frequency. Furthermore, the print elements 918 are arranged on the print element substrate 228 at a high density (for example, 600 dpi or higher). For this reason, there is a risk that the heat will have an adverse effect on adjacent print elements 918.

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

[0094] 13, the wiring layer 1306 extends toward the front or rear of the page, and the wiring layer 1306 extending toward the rear or front is connected to the base 1302 by a heat dissipation contact 1340b in a position where there is no underlying insulating layer 1338. The heat dissipation contacts 1340a and 1340b are each formed at a position that does not overlap with the write element 918 in a plane that intersects (orthogonal in this embodiment) the stacking direction of the wiring layers (see FIG. 12(b)). In other words, the heat dissipation contacts 1340a and 1340b are positioned away from directly below the write 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-controlled heat generating element 1204, it is possible to dissipate not only the heat generated by the recording element but also the heat generated by the nearby temperature-controlled heat generating element to the base 1302. Furthermore, by providing the heat dissipation contact 1340b between adjacent recording elements 918, it is possible to dissipate not only the heat from the recording element 918 connected by the heat dissipation wiring layer 1330, but also the heat from the adjacent recording elements 918 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 recovered by 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. Because ink may dissolve the interlayer insulating film, each wiring layer is provided at a certain distance from the supply port 914. This prevents short circuits between the ink and the wiring. The wiring layers 1310 and 1312 and the wiring layers 1306 and 1308 are located at different distances from the supply port 914, with the wiring layers 1310 and 1312 (see distance X in FIG. 13) being closer than the wiring layers 1306 and 1308 (see distance Y in FIG. 13). This is to enable early detection of a VH leak, which is likely to occur if a short circuit occurs between the wiring layers 1310 and 1312 and the ink, and to prevent malfunction of the printing apparatus.

[0097] <Infection Retardation Section> The heat transfer members 1314a and 1314b connected to the printing elements 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 printing element power supply voltage VH is applied is often destroyed because current flows first. If the heat transfer member 1314a is destroyed, ink may come into contact with the destroyed heat transfer member 1314a, or, if the destruction is severe, 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, corrosion by the ink will progress because the printing element power supply voltage VH is applied to these. Eventually, corrosion will progress to the wiring layer 1310, which is commonly connected to all the printing elements 918, and a break in one printing element 918 may render all of the printing elements 918 unusable.

[0099] Therefore, in this embodiment, the recording element substrate 228 is provided with a transmission delay portion 1342 for delaying the transmission of corrosion caused by ink to the wiring layer 1310 when the wiring to the recording elements 918 is broken. The transmission delay 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. In other words, the recording element substrate 228 is connected to the wiring layer 1310, which is the power wiring, via the transmission delay portion 1342 that is formed to make a detour in the stacking direction of the wiring layers.

[0100] Specifically, in the infection delay unit 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 infection delay unit 1342 are insulated from the wiring in the corresponding wiring layer. As a result, corrosion does not propagate directly from the members of the wiring layer 1312 to the wiring portion 1347, but instead travels from the member 1313 of the wiring layer 1312 via the member 1344 to the member 1309 of the wiring layer 1308, before reaching the wiring portion 1347 of the wiring layer 1310. In this manner, in this embodiment, the infection retardation portion 1342 is formed by being laminated on the base 1302 via the heat storage layer 1304, and functions as a heat transfer layer connecting the recording element 918 and the wiring layer 1310.

[0101] Furthermore, in the transmission retardation section 1342, the connection position of the heat transfer member between the components of each layer is located at or near the edge of the component. Near the edge is, for example, within 5 μm of the edge. This ensures the length of the corrosion propagation path, increasing the time it takes for the corrosion to reach the wiring layer 1310 and extending the life of the printing element substrate 228. With this configuration, even if a specific printing element fails, the specific printing element can be placed in a non-ejection state, ensuring reliability and allowing continued use. Note that in this embodiment, the transmission retardation section 1342 is configured to bypass the wiring layer 1308, but this is not a limitation. For example, the transmission retardation section 1342 may be configured to bypass the wiring layer 1306. In this case, the transmission retardation section 1342 and the heat dissipation contact 1340 are positioned so as not to interfere with each other.

[0102] <Prevents burning> The recording element substrate 228 is configured to be able to suppress kogation that accumulates on the upper protective layer 1322 due to the driving of the recording elements 918. Kogation occurs when coloring materials and additives contained in ink are decomposed at the molecular level by high-temperature heating, turning into hardly soluble substances, and these substances are then physically adsorbed onto the surface of the upper protective layer 1322.

[0103] In the recording element substrate 228, to suppress kogation, the electrode 1210 is provided directly above the recording elements 918 of the upper protective layer 1322, 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 operations. This allows particles such as pigments in the ink that are negatively charged to be kept away from the surface of the electrode 1210, that is, the surface of the upper protective layer 1322 above the recording elements 918.

[0104] In this way, by reducing the proportion 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 proportion of coloring materials, additives, and the like that cause kogation near the surface of the upper protective layer 1322 is reduced, thereby suppressing the occurrence of kogation.

[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 state where the potential is controlled and in a state where the potential is not controlled. In a state where the potential between the electrode 1210 and the counter electrode 1212 is not controlled, negatively charged particles 1402 in the ink in the pressure chamber 920 are dispersed approximately uniformly in the ink, 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 approximately 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 near 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 counter electrode 1212 and the electrode 1210, Vc and Vh, the more the negative potential particles 1402 that cause kogation are repelled from the electrode 1210, making it less likely for kogation to occur on the electrode 1210. Kogation adhering to the electrode 1210, i.e., kogation adhering near the surface of the upper protective layer 1322, is removed by applying a voltage between the electrode 1210 and the counter electrode 1212, causing the surface of the upper protective layer 1322 to dissolve into ink and lift off the kogation. At this time, a voltage of 3 V or higher is applied between the electrode 1210 and the counter electrode 1212, which dissolves the iridium, the electrode material. It is also preferable to determine the direction of the voltage applied to the electrode 1210 during this process. This removal of the kogation leaves the surface of the electrode 1210 virtually free of kogation.

[0108] If ink is ejected when there is almost no kogation on the upper protective layer 1322 after kogation removal, significant kogation will occur on the upper protective layer 1322. As a result, the ejection characteristics change significantly within a certain period of time immediately after kogation removal. For this reason, after 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 explained above, in the print element substrate, 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 print element and between adjacent print elements. This allows for pinpoint heat dissipation in areas where high heat dissipation efficiency is required. This reduces the area occupied by the heat dissipation contacts, contributing to the miniaturization and high density of the print element substrate.

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

[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 print elements 918 and the heat dissipation contacts 1340a are arranged in a one-to-one relationship between each print element 918 and the temperature control heat generating element 1204. However, this is not limited to this. For example, one heat dissipation contact 1340a may be arranged for multiple print elements 918. Although not specifically described in the above embodiment, the heat dissipation contacts 1340b corresponding to the print elements 918 located at both ends of the print element array are provided, for example, outside the print element array. Furthermore, in the above embodiment, the heat dissipation contacts 1340b are arranged between adjacent print elements 918, and one heat dissipation contact 1340b corresponds to one print element 918. However, this is not limited to this. For example, the heat dissipation contacts 1340b may be arranged every other adjacent print element 918. In this case, one heat dissipation contact 1340b corresponds to two print elements 918.

[0113] (2) In the above embodiment, the area of ​​the upper protective layer 1322 exposed 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 this. For example, as shown in Figure 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 ink bubble formation. For example, when the size of the recording element 918 is 15 μm × 20 μm, the electrode 1210 is 19 μm × 24 μm and is formed with chamfered corners.

[0114] (3) Although not specifically mentioned in the above embodiment, the voltage applied between the electrode 1210 and the counter electrode 1212 may be reversed during the kogation removal process, which dissolves and reduces not only the electrode 1210 but also the counter electrode 1212. The counter electrode 1212 is arranged near the recovery port 916, for example, with a size of 20 μm × 20 μm, so as not to come into contact with components used to eject ink from the nozzles, such as the recording elements 918. Furthermore, although not specifically mentioned in the above embodiment, the temperature-controlling heating element 1204 is made of, for example, polysilicon (POL) or aluminum (AL). The temperature-controlling heating element 1204 may have the same configuration as the recording elements 918.

[0115] (4) The above embodiment is not limited to a recording device that ejects ink onto a recording medium, but can also be applied to various liquid ejection devices that eject liquid to obtain a finished 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 spans the entire width of the recording area on the recording medium, but this is not limited to this. It may also be a so-called serial scan type recording device that uses a recording head that ejects ink while moving in a direction intersecting the recording medium transport direction.

[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 substrate for a liquid ejection head capable of ejecting liquid using 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 adjusting the temperature 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 is characterized in that 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 heat generating elements. (Configuration 2) 2. The liquid ejection head substrate according to configuration 1, wherein the first heat transfer member does not overlap the energy generating element in a plane intersecting with the 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 the temperature of the energy generating element. (Configuration 4) a second heat transfer layer formed on the base via the insulating layer and connecting the energy generating element and a power supply wiring; 4. The liquid ejection head substrate according to any one of configurations 1 to 3, wherein the second heat transfer layer connects the energy generating elements and the power supply wiring by making a detour in the stacking direction of the second heat transfer layer. (Configuration 5) The second heat transfer layers are connected to each other 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 the ends 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. (Configuration 7) A plurality of the energy generating elements are arranged in a predetermined direction, the temperature control heat generating 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 the drive control resolution of the temperature control heat generating elements is coarser than the drive control resolution of the energy generating elements. (Configuration 8) 8. The liquid ejection head substrate according to configuration 7, wherein the driving elements for driving the temperature control heat generating elements are disposed between the energy generating elements adjacent to each other. (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 according to 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 first heat transfer member 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 first heat transfer member is provided for a plurality of 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 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 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 device according to Configuration 18, further comprising a circulation path that can circulate 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 substrate for a liquid ejection head capable of ejecting liquid using 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 adjusting the temperature 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 heat generating 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 the 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 the temperature of the energy generating element.

4. a second heat transfer layer formed on the base via the insulating layer and connecting the energy generating element and a power supply wiring; The liquid ejection head substrate according to claim 1 , wherein the second heat transfer layer connects the energy generating elements and the power supply wiring by making a detour in the stacking direction of the second heat transfer layer.

5. The second heat transfer layers are connected to each other by a second heat transfer member, 5. 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.

7. A plurality of the energy generating elements are arranged in a predetermined direction, the temperature control heat generating 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 the driving elements for driving the temperature control heat generating elements are 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-controlling 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. A substrate for a liquid ejection head as described in claim 9, wherein the first heat transfer member arranged between adjacent energy generating elements extends to the vicinity of the temperature-controlling heat generating element arranged on the other side of the arranged energy generating elements, or is arranged closer to the temperature-controlling heat generating element arranged on the other side of the arranged energy generating elements.

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

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

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

15. A liquid ejection head comprising the liquid ejection head substrate according to any one of claims 1 to 14.

16. 16. The liquid ejection head according to claim 15, wherein the liquid ejection head substrate has a rectangular shape having long 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. 19. The liquid ejection apparatus according to claim 18, further comprising a circulation path that is 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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