Recording element substrate, liquid ejection head, and liquid ejection apparatus

Abstract

An object of the present disclosure is to provide a printing element substrate capable of accurately detecting the temperature in the entire region and performing highly accurate temperature control.SOLUTION: The printing element substrate includes an energy generation element array, a temperature detection element array, a heating element array, and a plurality of unit areas each including an energy generation element, a temperature detection element, and a heating element. Of the plurality of unit areas, in a second unit area arranged at a position closer to the first end than a first unit area arranged near the center of the print element substrate, the temperature detection element is arranged at a position closer to the first end.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] The volume and speed of droplets of liquid ejected from a recording element substrate used in a liquid ejection device that ejects liquid to perform printing change depending on the temperature. If a temperature distribution occurs in the recording element substrate, that temperature distribution will directly result in unevenness in the image, raising concerns about a decline in image quality. For this reason, it is necessary to control the temperature of the recording element substrate so that the temperature distribution within the substrate is maintained within an appropriate range.

[0003] Patent Document 1 discloses a recording element substrate in which multiple heating areas are evenly arranged on the left and right, each of which includes a heater for liquid ejection, a sub-heater for temperature adjustment, a driver for driving these, and a temperature detection element for detecting the temperature of the element substrate.The recording element substrate of Patent Document 1 makes it easier to equalize the temperatures among the multiple heating areas, thereby suppressing degradation of image quality. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-213874 Summary of the Invention [Problem to be solved by the invention]

[0005] In the printing element substrate of Patent Document 1, the heaters, sub-heaters, drivers, and temperature detection elements are arranged so that their positional relationships are equal in all heating areas (unit areas). Therefore, when viewed across the entire printing element substrate, the gradient of the temperature distribution within the unit area is greater at the edges, where heat is more likely to escape to the periphery, than at the center, and the accurate average temperature within the unit area cannot be detected, which can make it impossible to perform appropriate temperature control.

[0006] Therefore, an object of the present disclosure is to provide a recording element substrate that can detect temperature accurately over the entire area and perform highly accurate temperature control. [Means for solving the problem]

[0007] The recording element substrate of the present disclosure is a recording element substrate that performs recording by ejecting liquid, and includes: an energy generating element array in which a plurality of energy generating elements that generate energy for ejecting liquid are arranged along a first direction; a temperature detecting element array in which a plurality of temperature detecting elements for detecting the temperature of the recording element substrate are arranged along the first direction; and a heating element array in which a plurality of heating elements for heating the recording element substrate are arranged along the first direction, and is characterized in that it includes a plurality of unit areas that include the energy generating elements, the temperature detecting elements, and the heating elements, and in a second unit area of ​​the plurality of unit areas that is arranged at a position closer to a first end of the recording element substrate than a first unit area that is arranged near the center of the recording element substrate, the temperature detecting element is arranged at a position closer to the first end. [Effects of the Invention]

[0008] According to the recording element substrate of the present disclosure, it is possible to detect the temperature accurately over the entire area and perform highly accurate temperature control. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of a liquid ejection apparatus that can be applied to an embodiment. [Figure 2] FIG. 1 is a schematic perspective view of a liquid ejection head that can be applied to an embodiment. [Figure 3] FIG. 1 is a schematic plan view of an element substrate that can be applied to an embodiment. [Figure 4] FIG. 10 is a diagram showing a circuit for driving a heating element. [Figure 5] FIG. 10 is a block diagram showing how the control signals for the heating elements are generated within the element substrate. [Figure 6] FIG. 10 is a block diagram showing a state in which a selection signal for a temperature detection element is generated within an element substrate. [Figure 7] FIG. 10 is a block diagram showing a state in which a control signal for a heating element is supplied from outside the element substrate. [Figure 8] FIG. 1 is a plan view showing an example of an element substrate that can be applied to an embodiment. [Figure 9] FIG. 1 is a plan view showing an example of an element substrate that can be applied to an embodiment. [Figure 10] FIG. 1 is a plan view showing an example of an element substrate that can be applied to an embodiment. [Figure 11] FIG. 1 is a plan view showing an example of an element substrate that can be applied to an embodiment. [Figure 12] FIG. 1 is a plan view showing an example of an element substrate that can be applied to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] <Liquid discharge device 100> FIG. 1(a) is a perspective view showing an example of a liquid ejection device 100 that can be applied to this embodiment.

[0011] The coordinate axes in the figure will be explained. The ±X direction indicates the longitudinal direction of the liquid ejection head 101. The ±Y direction indicates the lateral direction of the liquid ejection head 101. The -Y direction is the transport direction of the recording medium P. The -Y direction will be referred to as the transport direction as appropriate. The Z direction indicates the height direction of the liquid ejection head 101. The -Z direction is the direction in which liquid (e.g., ink) is ejected from the liquid ejection head 101. The surface of the liquid ejection head 101 facing the -Z direction is the bottom surface of the liquid ejection head 101.

[0012] In this disclosure, "recording" does not only mean forming meaningful information (for example, characters or figures that are visible to humans). "Recording" also means forming insignificant information. Furthermore, in this disclosure, "recording" broadly means forming an image, a design, a pattern, a structure, or a combination thereof on recording medium P, or processing the medium.

[0013] "Recording medium" includes not only paper used in general liquid ejection devices, but also anything that can accept liquid (for example, ink), such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, and leather.

[0014] The recording medium P may be any medium on which an image can be formed by impacting droplets (e.g., ink droplets). For example, various materials and forms can be used, such as paper, cloth, optical disc label surfaces, plastic sheets, overhead projector sheets, and envelopes. In this embodiment, the description will be given assuming that cut paper is used as the recording medium P.

[0015] In this embodiment, the description will be made assuming that ink is used as the liquid. However, the liquid that can be used in the technology of the present disclosure is not limited to ink. In addition to ink, various recording liquids can be used as the liquid, including treatment liquids used for the purposes of improving the fixation of ink on the recording medium P, reducing uneven gloss, and improving abrasion resistance.

[0016] 1(a), the liquid ejection device 100 includes a long liquid ejection head 101 that extends across the entire area in the width direction (X direction) of the recording medium P. In this embodiment, a so-called full-line type liquid ejection head 101 is used.

[0017] The recording medium P is continuously transported in a transport direction by a transport mechanism 102 including a transport belt and the like. While the recording medium P is transported in the transport direction, liquid (e.g., ink) is ejected from the liquid ejection heads 101 to perform recording on the recording medium P. In this embodiment, liquid ejection heads 101C, 101M, 101Y, and 101Bk are used as the liquid ejection heads 101, which eject cyan (C), magenta (M), yellow (Y), and black (Bk) inks. This allows a color image to be formed.

[0018] FIG. 1B is a block diagram of the control system of the liquid ejection device 100. As shown in FIG.

[0019] As shown in FIG. 1B, the CPU 120 controls the entire liquid ejection apparatus 100 in accordance with a program stored in a ROM 121 while using a RAM 122 as a work area.

[0020] For example, the CPU 120 controls the temperature of the recording element substrate 200 (see FIG. 2) by driving the heating element 304 (see FIG. 3) based on the temperature acquired by a temperature detection element 306 (see FIG. 3) described later.

[0021] Furthermore, the CPU 120 performs predetermined image processing on image data received from an externally connected host device 130 in accordance with programs and parameters stored in the ROM 121, generating ejection data compatible with the liquid ejection head 101. The CPU 120 then drives the liquid ejection head 101 in accordance with this ejection data, causing liquid to be ejected from each ejection port (not shown) at a predetermined frequency. Furthermore, while the liquid ejection head 101 is performing such an ejection operation, the CPU 120 drives the conveyance motor 123 to rotate the conveyance mechanism 102 (see FIG. 1(a)), thereby conveying the recording medium P (see FIG. 1(a)) in the conveyance direction at a speed corresponding to the ejection frequency.

[0022] <Liquid ejection head 101> FIG. 2 is a schematic perspective view showing the bottom surface of a liquid ejection head 101 that can be applied to this embodiment.

[0023] 2, this embodiment uses a full-line liquid ejection head 101 in which a plurality of recording element substrates 200 are arranged along a direction (for example, the X direction) that intersects (in this embodiment, is nearly perpendicular to) the transport direction. The recording element substrate 200 comprises an element substrate 301 (see FIG. 3) including energy generating elements that generate energy for ejecting liquid, and an ejection port forming member (not shown) in which ejection ports (not shown) for ejecting liquid are formed.

[0024] The ejection port forming member includes pressure chambers that temporarily store liquid supplied from a supply port 305 (see FIG. 3) and receive pressure when the liquid is ejected, and ejection ports formed at positions corresponding to the energy generating elements. In FIG. 2, the shape of the recording element substrate 200 is a parallelogram when the liquid ejection head 101 is viewed from the bottom. However, the shape of the recording element substrate 200 may be rectangular (for example, oblong). In the following description, the shape of the recording element substrate 200 is assumed to be rectangular.

[0025] 2, pad rows 302a (see FIG. 3) are formed along the X direction on both the +Y direction end and the -Y direction end of the recording element substrate 200, and a flexible wiring substrate 202 is connected to each pad row. However, the pad row 302a and the flexible wiring substrate 202 may be arranged on either the +Y direction side or the -Y direction side of the recording element substrate 200. In this embodiment, a configuration in which the pad row 302a is formed only on the -Y direction side will be described.

[0026] <Element substrate 301> 3 is a schematic bottom view of an element substrate 301 that can be applied to this embodiment. Note that, although dashed lines indicating areas are shown in FIG. 3, these dashed lines are virtual lines shown for the sake of convenience of explanation.

[0027] 3, the element substrate 301 includes pads 302 to which the flexible wiring substrate 202 (see FIG. 2) can be connected, and heaters 303 that serve as energy generating elements for ejection. The element substrate 301 includes heating elements 304 that control the heating of the element substrate 301, supply ports 305 that supply liquid, and temperature detection elements 306 that detect the temperature. A plurality of heaters 303 are arranged along a first direction (the longitudinal direction (X direction) of the element substrate 301) to form an energy generating element array (heater array).

[0028] In a plan view of the bottom surface of the element substrate 301, heating elements 304 for heating the element substrate 301 are arranged on both sides of the heater array. A heating element array is formed by arranging the plurality of heating elements 304 along a first direction.

[0029] When the bottom surface of the element substrate 301 is viewed from above, supply ports 305 are formed outside the two heating elements 304, penetrating the element substrate 301 in the height direction (Z direction) to supply liquid from the element substrate 301 to a discharge port forming member (not shown). A supply port array is formed by arranging the plurality of supply ports 305 along a first direction. The discharge port forming member (not shown) is bonded to the surface facing the front side in FIG. 3. Liquid is supplied to the upper layer of the heater 303 (the surface facing the front side in FIG. 3) through the supply ports 305. Then, film boiling occurs in the liquid as the heater 303 generates heat, and the liquid is discharged from the discharge ports of the discharge port forming member toward the -Z direction (the front side in FIG. 3) as the generated bubbles grow.

[0030] When the bottom surface of the element substrate 301 is viewed from above, a temperature detection element 306 for detecting the temperature of the element substrate 301 is arranged to the left of the supply port array formed on the left side of each heater array. A temperature detection element array is formed by arranging multiple temperature detection elements 306 along a first direction. The element substrate 301 has multiple unit areas 307, which serve as units of temperature control, and each area includes multiple energy generating elements (heaters 303 in this embodiment), two heating elements 304, and one temperature detection element 306. The heating elements 304 are elements for heating the element substrate 301 and the liquid to keep them warm. In other words, the heating elements 304 function as sub-heaters. The heating elements 304 are symmetrically arranged in rows on both sides of each heater array.

[0031] In this embodiment, the viscosity of a liquid decreases as the temperature increases. Therefore, if the liquid is heated using heating elements 304 arranged asymmetrically with respect to the heater array, the viscosity balance between the left and right sides may be disrupted, resulting in an asymmetrical liquid bubble shape. As a result, the accuracy of the landing position of the ejected droplets on the paper surface may decrease. Therefore, in this embodiment, the heating elements 304 are arranged symmetrically with respect to the heater array, thereby minimizing the impact on the landing accuracy of the droplets when heated using the heating elements 304.

[0032] In this embodiment, 28 unit areas 307, each including eight heaters 303, are provided as the minimum division. Seven unit areas 307 provided as the minimum divisions are provided along the first direction, and four are provided along the second direction (the short-side direction (Y direction) of the element substrate 301). In each of these unit areas 307, one temperature detection element 306 that detects the temperature of the element substrate 301 and two heating elements 304 are arranged as one set. Note that each unit area 307 in this embodiment includes eight supply ports 305 (two supply port rows). In this way, the same numbers of heaters 303, heating elements 304, and supply ports 305 are arranged in all unit areas 307.

[0033] The numbers of supply ports 305, heaters 303, heating elements 304, and temperature detection elements 306 are not limited to the above numbers. As long as they can be arranged inside one unit area 307, the numbers of supply ports 305, heaters 303, heating elements 304, and temperature detection elements 306 may be any number.

[0034] In this embodiment, two supply ports 305 are arranged on each side of one heater 303. By arranging the two supply ports 305 symmetrically for one heater 303, the bubbling of the liquid also becomes symmetrical, and the ejected liquid lands on the paper surface with high precision, achieving high image quality. Furthermore, by supplying liquid after ejection from the supply ports 305 on both sides of the heater 303, the ejection frequency can be increased, and higher speeds can also be achieved.

[0035] In this embodiment, the element substrate 301 is divided into a first area 307a, a second area 307b, and a third area 307c, and temperature control is performed thereon.

[0036] In a plan view of the bottom surface of the element substrate 301, the first area 307a is located in the center of the element substrate 301 in the longitudinal direction (X direction). The first area 307a includes 20 of the 28 unit areas 307 described above. Of these 20 unit areas 307, five are provided along the first direction, and four are provided along a second direction (the short-side direction (Y direction) of the element substrate 301) that intersects (or is orthogonal to) the first direction (X direction).

[0037] The second area 307b is located at an end closer to the +X direction than the first area 307a. In the second area 307b, four unit areas 307 are provided along the second direction.

[0038] The third area 307c is located at an end closer to the −X direction than the first area 307a. In the third area 307c, four unit areas 307 are provided along the second direction.

[0039] In each of the 20 unit areas 307 provided in the first area 307a, the temperature detection elements 306 are arranged at the center in the first direction. In each of the four unit areas 307 provided in the second area 307b, the temperature detection elements 306 are arranged as close as possible to the end of the second area 307b on the +X direction side. In each of the four unit areas 307 provided in the third area 307c, the temperature detection elements 306 are arranged as close as possible to the end of the third area 307c on the -X direction side. In this way, in the second area 307b and the third area 307c, the temperature detection elements 306 are arranged as close as possible to the end of the element substrate 301 so as to be as far away from the center of the element substrate 301 as possible.

[0040] In this embodiment, a temperature detection element 306 is provided in each unit area 307, and heating of the heating elements 304 included in the same unit area 307 is controlled based on the temperature detected by this temperature detection element 306. The number of times the heater 303 is driven per unit time and the degree of heat generation vary depending on the image data, but by continuously controlling the heating of the heating elements 304 for each unit area, temperature variations within the element substrate 301 can be suppressed.

[0041] Compared to the unit areas 307 in the first area 307a, the unit areas 307 in the second area 307b and the third area 307c tend to have greater temperature variations because heat is more likely to escape to the outside of the element substrate 301. If the temperature detection element 306 is placed in the center in the X direction in the second area 307b, the temperature at the end in the +X direction is less likely to be reflected in the detected temperature information, and there is a risk that a temperature higher than the actual average temperature in the unit area 307 will be detected. This may result in inappropriate heating control by the heating element 304.

[0042] Therefore, in the second area 307b, the temperature detection element 306 is arranged on the +X side of the center in the X direction, making it easier for information about the edges to be included in the temperature information acquired by the temperature detection element 306. As a result, the temperature detection element 306 acquires temperature information weighted toward the edge temperatures, which tend to be relatively low, as temperature information for the entire unit area 307, and this temperature becomes closer to the actual average temperature for the entire unit area 307. As a result, heating control by the heating element 304 can be performed more appropriately. For the same reason, the temperature detection element 306 is arranged on the -X side of the center in the X direction for the third area 307c.

[0043] Compared to the second area 307b and the third area 307c, the first area 307a has a uniform temperature overall and is less susceptible to temperature variations. Therefore, in each unit area 307 of the third area 307c, a temperature detection element 306 is placed at the center in the X direction. This makes it possible to perform appropriate heating control in each of the unit areas 307.

[0044] In this embodiment, an NPN diode is used as the temperature detection element 306. The NPN diode has a larger current amplification factor than other diodes (for example, a PNP diode), which allows the element substrate 301 to be made smaller. If the temperature detected by the temperature detection element 306 is equal to or lower than a predetermined value, the heating element 304 heats the element substrate 301. As a result, the temperature of the liquid in each unit area 307 is maintained at a predetermined temperature suitable for ejection.

[0045] The element substrate 301 has two long sides extending in a first direction (X direction) and two short sides extending in a second direction (Y direction). At the end of the element substrate 301 on the -Y direction side, a plurality of pads for connecting to the outside are arranged along the long sides of the element substrate 301, forming a pad row 302a. The pads constituting the pad row 302a include signal pads for receiving selection data for heaters 303 to be driven for ejection, power supply pads, etc.

[0046] The heater 303 is configured so that a current is passed through these pads at any timing to heat the heater 303, causing the liquid to heat and bubble, and droplets can be ejected from the ejection port. Note that various elements such as a piezoelectric element can also be used as the energy generating element for ejecting droplets.

[0047] FIG. 4 is a diagram showing a circuit for driving the heating elements 304 in one unit area 307.

[0048] As shown in FIG. 4, in one unit area 307, two heating elements 304 are electrically connected in parallel to a driver 400 to efficiently heat the area around the heater 303 (not shown in FIG. 4).

[0049] The pad row 302a includes a first pad 401 and a second pad 402. The first pad 401 is a + power supply pad. The second pad 402 is a GND pad. The first pad 401 and the second pad 402 are used to supply power to the heating element 304, but may also be used as pads to supply power to the heater 303 (see FIG. 3) used to eject droplets.

[0050] In this embodiment, a transistor is used as the driver 400. The driver 400 is controlled by a control signal of the heating element 304. The control signal of the heating element 304 is input from a signal line 403. The driver 400 heats an arbitrary unit area 307 inside the element substrate 301 by simultaneously driving two heating elements 304.

[0051] FIG. 5 is a block diagram showing a configuration in which control signals for the heating elements 304 are generated within the element substrate 301. As shown in FIG.

[0052] 5, a first data processing circuit 500 for generating control signals for the heating elements 304 is provided in the element substrate 301. When the control signals for the heating elements 304 are generated in the element substrate 301, the control signal data is sent simultaneously with the image data, making it possible to control the heating elements 304 without increasing the number of pads 302.

[0053] FIG. 6 is a block diagram showing a configuration in which a selection signal for the temperature detection element 306 is generated within the element substrate 301. As shown in FIG.

[0054] The element substrate 301 includes switching elements for switching between the heating elements 304 (see FIG. 4, etc.) and the temperature detection elements 306. Each of the plurality of heating elements 304 and the plurality of temperature detection elements 306 is connected to a different switching element. In each of the plurality of unit areas 307 (see FIG. 4, etc.), a control signal for switching between the heating elements 304 and the temperature detection elements 306 is input to each of the plurality of switching elements.

[0055] 6, a second data processing circuit 601 for selecting a desired temperature detection element 306 is provided in the element substrate 301. The second data processing circuit 601 is connected to each temperature detection element 306 via a multiplexer 602. By sending selection signal data for the temperature detection element 306 simultaneously with the image data, it becomes possible to control the selection of the temperature detection element 306 without increasing the number of pads 302.

[0056] The pad row 302a (see FIG. 3) includes a third pad 603 and a fourth pad 604. The third pad 603 is connected to each temperature detection element 306. The fourth pad 604 is a GND pad (VSS). The characteristics of the temperature detection element 306 are measured by passing a constant current through the third pad 603 and reading the voltage value.

[0057] Temperature information of the element substrate 301 is acquired by converting information detected by changes in the characteristics of the temperature detection element 306 into electricity and inputting it via the pad array 302a to a main circuit outside the liquid ejection head 101 that controls the liquid ejection head 101 (see FIG. 1). This temperature information may be input to a control circuit within the element substrate 301 instead of the main circuit. The temperature of the element substrate 301 can also be detected with this configuration.

[0058] The detected temperature information is compared with a predetermined set temperature in a control circuit outside or within the element substrate 301. If the temperature of a certain unit area 307 is lower than the predetermined temperature, a control signal is input from a signal line 403 (see FIG. 4, etc.) connected to a driver 400 (see FIG. 4, etc.) corresponding to this unit area 307.

[0059] Then, the control signal drives the heating element 304 (see FIG. 4, etc.) provided in that unit area 307. On the other hand, if the temperature detection element 306 detects a temperature higher than a predetermined temperature, the driving of the heating element 304 (not shown in FIG. 6) corresponding to that unit area 307 is controlled to stop.

[0060] As described above, in this embodiment, the heaters 303 and the heating elements 304 are arranged in all of the unit areas 307. In each unit area 307 provided in the first area 307a, the temperature detection element 306 is arranged at the center in the X direction.

[0061] Furthermore, in each unit area 307 provided in the second area 307b and the third area 307c, the temperature detection element 306 is arranged as far away as possible in the longitudinal direction from the center of the element substrate 301. With this configuration, it becomes possible to detect an average temperature that is close to the actual temperature in each unit area 307 of the element substrate 301, and the accuracy of temperature detection can be made approximately uniform across the entire substrate.

[0062] Therefore, according to the recording element substrate of this embodiment, it is possible to detect the temperature with high accuracy over the entire area and perform highly accurate temperature control.

[0063] Furthermore, since the accuracy of temperature detection in each unit area 307 is approximately uniform, the accuracy of heating control by the heating elements 304 in each unit area 307 is also approximately uniform. In this way, according to the liquid ejection device equipped with the liquid ejection head of the present disclosure, heating control is performed with greater accuracy than in conventional techniques, and degradation of image quality can be suppressed more than in conventional techniques.

[0064] <Modification of the first embodiment> FIG. 7 is a block diagram showing a modified example of the configuration in which the control signal for the heating element 304 is supplied from outside the element substrate 301. In FIG.

[0065] 7, the first data processing circuit 500 is disposed outside the element substrate 301. Even with this configuration, it is possible to detect temperature more accurately than with the prior art.

[0066] [Second embodiment] A second embodiment of the technology of the present disclosure will be described below with reference to the drawings. In the following description, the same names and symbols are used for configurations that are similar to or correspond to those of the first embodiment, and descriptions thereof will be omitted, and differences will be mainly described.

[0067] This embodiment provides a technique that can detect the temperature with high accuracy even when the recording element substrate is elongated.

[0068] FIG. 8 is a plan view showing an example of an element substrate 301 that can be applied to this embodiment.

[0069] 8, the element substrate 301 of this embodiment has a unit area 800. The unit area 800 includes a unit area 801, a unit area 802, a unit area 803, a unit area 804, a unit area 805, a unit area 806, and a unit area 807. When the bottom surface of the element substrate 301 is viewed from above, the unit areas 804, 803, 802, 801, 805, 806, and 807 are arranged in this order from one end to the other end in the longitudinal direction (X direction).

[0070] In this embodiment, temperature detection by the temperature detection element 306 and heating control by the heating element 304 are performed for each of these seven unit areas. In a unit area 801 located at the center in the X direction, the temperature detection element 306 is disposed at the center of the unit area 801 in the X direction (center C of the element substrate 301 in the X direction).

[0071] In a unit area 802 adjacent to the unit area 801 on the +X direction side, the temperature detection element 306 is arranged on the +X direction side of the center of the unit area 802 in the X direction. The distance from the temperature detection element 306 in the unit area 802 to the end of the unit area 802 on the +X direction side is shorter than the distance from the temperature detection element 306 in the unit area 801 to the end of the unit area 801 on the +X direction side.

[0072] In a unit area 803 adjacent to the unit area 802 on the +X direction side, the temperature detection element 306 is arranged on the +X direction side of the center of the unit area 803 in the X direction. The distance from the temperature detection element 306 in the unit area 803 to the end of the unit area 803 on the +X direction side is shorter than the distance from the temperature detection element 306 in the unit area 802 to the end of the unit area 802 on the +X direction side.

[0073] In a unit area 804 adjacent to the unit area 803 on the +X direction side, the temperature detection element 306 is arranged on the +X direction side of the center of the unit area 804 in the X direction. The distance from the temperature detection element 306 in the unit area 804 to the end of the unit area 804 on the +X direction side is shorter than the distance from the temperature detection element 306 in the unit area 803 to the end of the unit area 803 on the +X direction side.

[0074] On the other hand, in a unit area 805 adjacent to the unit area 801 on the -X direction side, the temperature detection element 306 is arranged on the -X direction side of the center of the unit area 805 in the X direction. The distance from the temperature detection element 306 in the unit area 805 to the end of the unit area 805 on the -X direction side is shorter than the distance from the temperature detection element 306 in the unit area 801 to the end of the unit area 801 on the -X direction side.

[0075] In a unit area 806 adjacent to the unit area 805 on the -X direction side, the temperature detection element 306 is arranged on the -X direction side of the center of the unit area 806 in the X direction. The distance from the temperature detection element 306 in the unit area 806 to the end of the unit area 806 on the -X direction side is shorter than the distance from the temperature detection element 306 in the unit area 805 to the end of the unit area 805 on the -X direction side.

[0076] In a unit area 807 adjacent to the unit area 806 on the -X direction side, the temperature detection element 306 is arranged on the -X direction side of the center of the unit area 807 in the X direction. The distance from the temperature detection element 306 in the unit area 807 to the end of the unit area 807 on the -X direction side is shorter than the distance from the temperature detection element 306 in the unit area 806 to the end of the unit area 806 on the -X direction side.

[0077] In this manner, in this embodiment, the temperature detection elements 306 are arranged in the longitudinal direction (X direction) so that the distance from the temperature detection elements 306 to the end of the unit area gradually decreases with increasing distance from the center C of the element substrate 301. In other words, the closer a unit area is arranged to the end of the element substrate 301, the shorter the distance from the temperature detection elements 306 to the end of the unit area becomes.

[0078] For example, the distance from the temperature detection elements 306 to the ends of the unit areas is shortest in the unit area 804 located closest to the +X direction and in the unit area 807 located closest to the -X direction. This allows the multiple temperature detection elements 306 to be uniformly arranged over the entire area, from end to end, of the element substrate 301. This configuration is particularly effective when the length of the element substrate 301 in the X direction is increased.

[0079] When the print head is lengthened to accommodate large-sized paper and the length of the print element substrate in the X direction is also lengthened, a temperature difference is likely to appear between the center and the edges of the element substrate 301. As in this embodiment, the temperature detection elements 306 are arranged so that the farther a unit area is located from the center C, the farther from the center C the unit area is located, thereby making it possible to detect the temperature of each unit area with high accuracy.

[0080] Therefore, according to the technology of this embodiment, even if the recording element substrate is elongated, the temperature can be detected with high accuracy.

[0081] [Third embodiment] Hereinafter, a third embodiment of the technology of the present disclosure will be described with reference to the drawings. In the following description, the same names and symbols are used for configurations that are similar to or correspond to those of the first and second embodiments, and descriptions thereof will be omitted, and differences will be mainly described.

[0082] This embodiment provides a printing element substrate that can accurately detect the temperature at the end opposite to the end where the pad row 302a is arranged.

[0083] FIG. 9 is a plan view showing an example of an element substrate 301 that can be applied to this embodiment.

[0084] 9, the unit area 900 of the element substrate 301 includes unit areas 901, 902, 903, and 904, which are arranged in this order along the second direction (Y direction) from the side closest to the pad row 302a. Of the unit areas 901, 902, 903, and 904, the unit area 904 is located at the farthest position from the pad row 302a. In the unit area 904, the multiple temperature detection elements 306 are arranged as far away as possible from the pad row 302a.

[0085] When the pad row 302a is arranged at the end of one side (the -Y direction side in this embodiment) of the element substrate 301, the distance between the heater 303 and the end on the opposite side (the +Y direction side) becomes closer. Therefore, the temperature of the unit area 904 tends to be lower than that of the other unit areas. In other words, there is a risk of a difference occurring between the discharge of the unit area 904 and the discharge of the unit areas 901 to 903.

[0086] Therefore, in the unit area 904 of this embodiment, multiple temperature detection elements 306 are arranged along the end (end on the +Y direction side) of the element substrate 301 so as to be as far away as possible from the pad row 302a. This allows a drop in temperature in the unit area 904 located at the farthest position from the pad row 302a to be effectively reflected in the temperature detection.

[0087] Therefore, according to the element substrate 301 of this embodiment, it is possible to accurately detect the temperature at the end opposite to the end where the pad row 302a is arranged, and to perform highly accurate temperature control.

[0088] [Fourth embodiment] Hereinafter, a fourth embodiment of the technology of the present disclosure will be described with reference to the drawings. In the following description, the same names and symbols are used for configurations that are similar to or correspond to those of the first to third embodiments, and descriptions thereof will be omitted, and differences will be mainly described.

[0089] This embodiment provides a recording element substrate that can detect the temperature of the corner with high accuracy.

[0090] FIG. 10 is a plan view showing an example of an element substrate 301 that can be applied to this embodiment.

[0091] 10, the element substrate 301 of this embodiment has four unit areas 1000 arranged at the corners. In each of these unit areas 1000, the temperature detection elements 306 are arranged close to the corners of the element substrate 301. Because the corners of the element substrate 301 are sandwiched between two sides, heat escapes more easily and the temperature drops more easily than at the ends, which are in contact with only one side.

[0092] Therefore, in this embodiment, the temperature detection elements 306 are arranged at the corners of the element substrate 301 so as to be close to the corners of the element substrate 301. This makes it easier for the temperature drop at the corners of the element substrate 301 to be reflected in the temperature detection, and enables effective temperature detection.

[0093] Therefore, according to the element substrate 301 of this embodiment, the temperature of the corners of the element substrate 301 can be detected with high precision, and highly accurate temperature control can be performed.

[0094] [Fifth embodiment] Hereinafter, a fifth embodiment of the technology of the present disclosure will be described with reference to the drawings. In the following description, the same names and symbols are used for configurations that are similar to or correspond to those of the first to fourth embodiments, and descriptions thereof will be omitted, and differences will be mainly described.

[0095] This embodiment provides an element substrate 301 that can detect the temperature of the edge and corner portions with high accuracy.

[0096] FIG. 11 is a plan view showing an example of an element substrate 301 that can be applied to this embodiment.

[0097] 11, two temperature detection elements 306 are arranged in a unit area 1100 located at the corner of the end (the end on the +Y direction side) opposite the end where the pad row 302a is arranged. In the unit area 1100, one temperature detection element 306 is arranged on the outside of each of the two supply port rows. For ease of explanation, in FIG. 11, these two temperature detection elements 306 will be referred to as temperature detection element 306a and temperature detection element 306b.

[0098] In the unit area 1100, the temperature detection element 306a is arranged on the line of the temperature detection element row 1100a, which is arranged at the end opposite to the pad row 302a (the end on the +Y direction side). On the other hand, the temperature detection element 306b is arranged in the unit area 1100 at a position as close as possible to a corner of the element substrate 301.

[0099] As described above, the temperature tends to drop more easily at the edges and corners of the element substrate 301 than at the center of the element substrate 301. Therefore, in this embodiment, temperature detection elements 306 are further added to each of the two corners on either side of the side opposite the pad row 302a (the side on the +Y direction side).

[0100] Therefore, according to the element substrate 301 of this embodiment, the temperatures of the end and corner portions can be detected with high precision, and highly accurate temperature control can be performed.

[0101] [Sixth embodiment] Hereinafter, a sixth embodiment of the technology of the present disclosure will be described with reference to the drawings. In the following description, the same names and symbols are used for configurations that are similar to or correspond to those of the first to fifth embodiments, and descriptions thereof will be omitted, and differences will be mainly described.

[0102] In the first to fifth embodiments, the pad array is arranged along the longitudinal direction (X direction) at the end on the -Y direction side of the element substrate. In contrast, in this embodiment, the pad array is arranged along the lateral direction (Y direction) at each end on the ±X direction sides of the element substrate. In this embodiment, a printing element substrate is provided that can detect temperature with high accuracy in a configuration in which the pad array is arranged along the lateral direction.

[0103] FIG. 12 is a plan view showing an example of an element substrate 301 that can be applied to this embodiment.

[0104] 12, in this embodiment, pad rows 302a are arranged along the short side direction (Y direction) at both ends of the element substrate 301 in the longitudinal direction (X direction). One supply port 305 is formed in the center of the element substrate 301 in the short side direction (Y direction) so as to extend along the long side direction (X direction). One heater array is formed on each side of the supply port 305. A heating element array is formed along the long side direction (X direction) on the outer side of the element substrate 301 than the ejection port array. A temperature detection element 306 is arranged on the outer side of the element substrate 301 than the heating element array.

[0105] In this embodiment, seven unit areas 1200 are formed along the longitudinal direction (X direction) and two are formed along the lateral direction (Y direction). Each of these 14 unit areas 1200 includes eight heaters 303, one heating element 304, and one temperature detection element 306. However, the numbers of heaters 303, heating elements 304, and temperature detection elements 306 are not limited to the above numbers. For ease of explanation, the four unit areas located at the four corners of these 14 unit areas 1200 will be referred to as "unit areas 1200a." In the unit areas 1200a, the temperature detection elements 306 are arranged as close to the corners of the element substrate 301 as possible.

[0106] For example, in a unit area 1200a located in the upper left corner of the figure, the temperature detection element 306 is arranged in the upper left corner. In a unit area 1200a located in the upper right corner of the figure, the temperature detection element 306 is arranged in the upper right corner. In a unit area 1200a located in the lower left corner of the figure, the temperature detection element 306 is arranged in the lower left corner. In a unit area 1200a located in the lower right corner of the figure, the temperature detection element 306 is arranged in the lower right corner.

[0107] In the unit areas 1200 other than these four, the temperature detection elements 306 are disposed at the ends in the short-side direction (Y) and at the center in the long-side direction (X direction) of each unit area 1200. In other words, the temperature detection elements 306 are uniformly disposed at positions close to the ends and corners of the element substrate 301, where the temperature is more likely to drop than in the center.

[0108] Therefore, according to the element substrate 301 of this embodiment, in a configuration in which the pad rows 302a are arranged at both ends in the longitudinal direction, the temperatures at the ends and corners can be detected with high accuracy, and highly accurate temperature control can be performed.

[0109] [Other embodiments] The above-described embodiments may be combined depending on the size of the recording element substrate and the state of heat dissipation from the end portions.

[0110] In the first embodiment, the temperature detection element is configured with an NPN diode. However, the configuration of the temperature detection element is not limited to an NPN diode as long as it can detect the temperature of the print element substrate. For example, even if a PNP diode is used as the temperature detection element 306, the same effects as in the first embodiment can be obtained.

[0111] The temperature detection element may also be formed from a layer that forms wiring. When this configuration is adopted, in order to increase the resistance value of the temperature detection location, for example, a single aluminum wiring layer may be formed in a snake-shaped planar layout at the relevant location. This configuration also provides the same effects as the first embodiment.

[0112] The present disclosure includes the following configurations or methods.

[0113] [Configuration 1] A recording element substrate that performs recording by ejecting liquid, an energy generating element array in which a plurality of energy generating elements that generate energy for ejecting liquid are arranged along a first direction; a temperature detection element array in which a plurality of temperature detection elements for detecting the temperature of the recording element substrate are arranged along the first direction; a heating element array in which a plurality of heating elements for heating the recording element substrate are arranged along the first direction, a plurality of unit areas including the energy generating element, the temperature detecting element, and the heating element; Equipped with In a second unit area of ​​the plurality of unit areas, the second unit area is arranged closer to a first end portion of the recording element substrate than a first unit area arranged near the center of the recording element substrate, and the temperature detection element is arranged closer to the first end portion. A recording element substrate comprising:

[0114] [Configuration 2] In the first unit area, the temperature detection element is disposed at the center in the first direction. 2. The recording element substrate according to claim 1.

[0115] [Configuration 3] In a third unit area that is arranged at a position close to a second end portion that is located on the opposite side to the side where the first end portion is located, with the center of the recording element substrate as a reference, the temperature detection element is arranged at a position close to the second end portion. 3. The recording element substrate according to claim 1 or 2.

[0116] [Configuration 4] In a fourth unit area disposed between the first unit area and the second unit area, the temperature detection element is disposed at a position close to an end portion of the fourth unit area that is closer to the second unit area; In a fifth unit area disposed between the first unit area and the third unit area, the temperature detection element is disposed at a position close to an end portion of the fifth unit area that is closer to the third unit area. The recording element substrate according to configuration 3.

[0117] [Configuration 5] a pad row including a plurality of pads arranged along the first direction at an end on one side in a second direction intersecting the first direction; In the unit area disposed at the farthest position from the pad row, the temperature detection element is disposed at a position closer to the other end in the second direction. 5. The recording element substrate according to any one of configurations 1 to 4.

[0118] [Configuration 6] In a unit area among the plurality of unit areas that is arranged near a corner of the recording element substrate, the temperature detection element is arranged at a position close to the corner of the recording element substrate. 6. The recording element substrate according to configuration 5.

[0119] [Configuration 7] In a unit area among the plurality of unit areas that is disposed in the vicinity of a corner of the recording element substrate at a position away from the pad row, the plurality of temperature detection elements are disposed so as to face each other with the heating element and the energy generating element interposed therebetween. 7. The recording element substrate according to claim 6.

[0120] [Configuration 8] a plurality of unit area rows, each of which is arranged along the first direction, are arranged along a second direction intersecting the first direction on a plane; in each unit area constituting a unit area row arranged at one end in the second direction among the plurality of unit area rows, the temperature detection element is arranged close to the one end in the second direction, In each unit area constituting a unit area row arranged at the other end in the second direction among the plurality of unit area rows, the temperature detection element is arranged closer to the other end in the second direction. 8. The recording element substrate according to any one of configurations 1 to 7.

[0121] [Configuration 9] The unit area includes at least one of the temperature sensing elements and at least one of the heating elements; 9. The recording element substrate according to any one of configurations 1 to 8.

[0122] [Configuration 10] Among the plurality of unit areas, unit areas excluding the second unit area and the third unit area have the same positional relationship between the temperature detection element and the heating element as the first unit area. 10. The recording element substrate according to any one of configurations 3 to 9.

[0123] [Configuration 11] The temperature detection element is composed of an NPN diode. 11. The recording element substrate according to any one of configurations 1 to 10.

[0124] [Configuration 12] The temperature detection element is composed of a layer forming wiring. 12. The recording element substrate according to any one of configurations 1 to 11.

[0125] [Configuration 13] a switching element for switching between the heating element and the temperature detection element; Each of the plurality of heating elements and the plurality of temperature detecting elements is connected to a different one of the switching elements. 13. The recording element substrate according to any one of configurations 1 to 12.

[0126] [Configuration 14] a control signal for switching selection between the heating element and the temperature detection element is input to each of the plurality of switching elements in each of the plurality of unit areas; 14. The recording element substrate according to claim 13.

[0127] [Configuration 15] The heating element heats the recording element substrate when the temperature detected by the temperature detection element corresponding to the heating element is equal to or lower than a predetermined temperature. 15. The recording element substrate according to any one of configurations 1 to 14.

[0128] [Configuration 16] a power supply pad for supplying power to the plurality of heating elements is the same power supply pad as a power supply for supplying power to the plurality of energy generating elements; 16. The recording element substrate according to any one of configurations 1 to 15.

[0129] [Configuration 17] power supply pads connected to the plurality of heating elements are connected to the same GND pad as the GND pad connected to the plurality of energy generating elements via the switching element; 17. The recording element substrate according to any one of configurations 13 to 16.

[0130] [Configuration 18] A recording element substrate according to any one of configurations 1 to 17, a plurality of the recording element substrates are arranged along the first direction; A liquid ejection head characterized by:

[0131] [Configuration 19] a liquid ejection head having a recording element substrate according to any one of configurations 1 to 17; a control unit that controls the temperature of the recording element substrate for each unit area by driving the heating element based on the temperature detected by the temperature detection element; A liquid ejection device comprising:

Claims

1. A recording element substrate that performs recording by ejecting liquid, an energy generating element array in which a plurality of energy generating elements that generate energy for ejecting liquid are arranged along a first direction; a temperature detection element array in which a plurality of temperature detection elements for detecting the temperature of the recording element substrate are arranged along the first direction; a heating element array in which a plurality of heating elements for heating the recording element substrate are arranged along the first direction, a plurality of unit areas including the energy generating element, the temperature detecting element, and the heating element; Equipped with In a second unit area of ​​the plurality of unit areas, the second unit area is disposed closer to a first end of the recording element substrate than a first unit area disposed near the center of the recording element substrate, and the temperature detection element is disposed closer to the first end. A recording element substrate comprising:

2. In the first unit area, the temperature detection element is disposed at the center in the first direction. The recording element substrate according to claim 1 .

3. In a third unit area that is arranged at a position close to a second end portion that is located on the opposite side to the side where the first end portion is located, with the center of the recording element substrate as a reference, the temperature detection element is arranged at a position close to the second end portion.

3. The recording element substrate according to claim 1.

4. In a fourth unit area disposed between the first unit area and the second unit area, the temperature detection element is disposed at a position close to an end portion of the fourth unit area that is closer to the second unit area; In a fifth unit area disposed between the first unit area and the third unit area, the temperature detection element is disposed at a position close to an end of the fifth unit area that is closer to the third unit area. The recording element substrate according to claim 3 .

5. a pad row including a plurality of pads arranged along the first direction at an end on one side in a second direction intersecting the first direction; In the unit area disposed at a position farthest from the pad row, the temperature detection element is disposed at a position closer to the other end in the second direction. The recording element substrate according to claim 1 .

6. In a unit area among the plurality of unit areas that is arranged near a corner of the recording element substrate, the temperature detection element is arranged at a position close to the corner of the recording element substrate. The recording element substrate according to claim 5 .

7. In a unit area among the plurality of unit areas that is disposed in the vicinity of a corner of the recording element substrate at a position away from the pad row, the plurality of temperature detection elements are disposed so as to face each other with the heating element and the energy generating element interposed therebetween.

7. The recording element substrate according to claim 6.

8. a plurality of unit area rows, each of which is arranged along the first direction, are arranged along a second direction intersecting the first direction on a plane; in each unit area constituting a unit area row arranged at one end in the second direction among the plurality of unit area rows, the temperature detection element is arranged close to the one end in the second direction, In each unit area constituting a unit area row arranged at the other end in the second direction among the plurality of unit area rows, the temperature detection element is arranged closer to the other end in the second direction. The recording element substrate according to claim 1 .

9. The unit area includes at least one of the temperature sensing elements and at least one of the heating elements. The recording element substrate according to claim 1 .

10. Among the plurality of unit areas, unit areas other than the second unit area and the third unit area have the same positional relationship between the temperature detection element and the heating element as the first unit area. The recording element substrate according to claim 3 .

11. The temperature detection element is composed of an NPN diode. The recording element substrate according to claim 1 .

12. The temperature detection element is composed of a layer forming wiring. The recording element substrate according to claim 1 .

13. a switching element for switching between the heating element and the temperature detection element; Each of the plurality of heating elements and the plurality of temperature detecting elements is connected to a different one of the switching elements. The recording element substrate according to claim 1 .

14. a control signal for switching selection between the heating element and the temperature detection element is input to each of the plurality of switching elements in each of the plurality of unit areas; The recording element substrate according to claim 13 .

15. The heating element heats the recording element substrate when the temperature detected by the temperature detection element corresponding to the heating element is equal to or lower than a predetermined temperature. The recording element substrate according to claim 1 .

16. a power supply pad for supplying power to the plurality of heating elements is the same power supply pad as a power supply for supplying power to the plurality of energy generating elements; The recording element substrate according to claim 1 .

17. power supply pads connected to the plurality of heating elements are connected to the same GND pad as the GND pads connected to the plurality of energy generating elements via the switching elements; The recording element substrate according to claim 13 .

18. A recording element substrate according to claim 1 or 2, a plurality of the recording element substrates are arranged along the first direction; A liquid ejection head characterized by:

19. a liquid ejection head having the recording element substrate according to claim 1 or 2; a control unit that controls the temperature of the recording element substrate for each unit area by driving the heating element based on the temperature detected by the temperature detection element; A liquid ejection device comprising:

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