JP2023114298A - Substrate, liquid discharge head, and liquid discharge device - Google Patents

Abstract

To provide a substrate which can efficiently obtain a temperature of a heating element mounted on a film, and to provide a liquid discharge head and a liquid discharge device.SOLUTION: A substrate according to an embodiment includes: a film substrate; a multilayer substrate; a solid pattern; and a thermistor. A heating element is mounted on the film substrate. The multilayer substrate has: a first layer which is connected with the film substrate and having a through hole formed; and a second layer laminated on the first layer. The solid pattern is provided between the first layer and the second layer. The solid pattern is formed of a metallic material. The thermistor is provided on the multilayer substrate and connected to the solid pattern through the through hole.SELECTED DRAWING: Figure 4

Description

Embodiments of the present invention relate to substrates, liquid ejection heads, and liquid ejection apparatuses.

Conventionally, a custom IC on a substrate is mounted on a film, such as a COF. Since the IC is a heating element, the IC may easily generate heat, or may reach an abnormal temperature in the event of a failure. Therefore, there is a demand for monitoring the temperature of the IC on the film. However, for reasons such as the inability to mount a thermistor on a film, techniques for mounting the thermistor on a separate substrate are known.

However, such a technique has the problem that the temperature of the IC cannot be accurately measured due to the physical distance between the IC whose temperature is to be monitored and the thermistor. Therefore, it is required to efficiently acquire the temperature of a heating element such as an IC mounted on a film.

Japanese Patent Application Laid-Open No. 2018-161787

A problem to be solved by the present invention is to provide a substrate, a liquid ejection head, and a liquid ejection apparatus capable of efficiently obtaining the temperature of a heating element mounted on a film.

A substrate of an embodiment includes a film substrate, a multilayer substrate, a solid pattern, and a thermistor. A heating element is mounted on the film substrate. The multilayer substrate has a first layer to which the film substrate is connected and through holes are formed, and a second layer laminated on the first layer. A solid pattern is provided between the first layer and the second layer. A solid pattern is formed of a metal material. A thermistor is provided on the multilayer substrate and connected to the solid pattern through the through hole.

1 is an explanatory diagram showing the configuration of a liquid ejection device according to an embodiment; FIG. 1 is a block diagram showing the configuration of a liquid ejection device according to an embodiment; FIG. 1 is a perspective view showing the configuration of a liquid ejection head according to an embodiment; FIG. 1 is a perspective view schematically showing the configuration of a substrate according to an embodiment; FIG. FIG. 2 is a side view schematically showing the configuration of the substrate according to the embodiment; FIG. 5 is an explanatory diagram showing the configuration of a liquid ejection device according to another embodiment;

A substrate 26, a liquid ejection head 10, and a liquid ejection apparatus 1 according to embodiments will be described below with reference to FIGS. 1 to 5. FIG. FIG. 1 is an explanatory diagram showing the configuration of the liquid ejection device 1 according to the embodiment, and FIG. 2 is a block diagram showing the configuration of the liquid ejection device 1. As shown in FIG. FIG. 3 is a perspective view showing the structure of the liquid ejection head 10 used in the liquid ejection device 1. As shown in FIG. 4 is a perspective view schematically showing the configuration of the substrate 26 used in the liquid ejection head 10, and FIG. 5 is a side view schematically showing the configuration of the substrate 26. As shown in FIG. In each figure, for the sake of explanation, the configuration is shown enlarged, reduced, or omitted as appropriate.

As shown in FIGS. 1 and 2, the liquid ejection device 1 includes, for example, a liquid ejection head 10, a liquid supply device 11, an interface 17, and a control board . The liquid ejecting apparatus 1 is, for example, an image forming apparatus such as an inkjet recording apparatus that ejects ink as liquid. Note that the liquid ejection apparatus 1 may be an inspection apparatus used for shipping inspections such as operation confirmation tests and performance tests of the liquid ejection head 10 after the liquid ejection head 10 is manufactured. The liquid ejection device 1 may be configured to have a plurality of liquid ejection heads 10 and a plurality of liquid supply devices 11 capable of ejecting different inks.

The liquid ejection apparatus 1 includes, for example, a transport device that moves a recording medium along a transport path including a print position facing the liquid ejection head 10, a maintenance device that performs maintenance of the liquid ejection head 10, various sensors, and an adjustment device.

The liquid ejection head 10 ejects ink as liquid, for example. The liquid ejection head 10 is connected to a liquid supply device 11 and is supplied with ink from the liquid supply device 11 . The liquid ejection head 10 may be, for example, a non-circulating head in which ink is supplied from the liquid supply device 11, or a circulation head in which ink circulates between itself and the liquid supply device 11. good too.

The liquid ejection head 10 ejects ink to form a desired image on a recording medium arranged opposite to it.

As shown in FIG. 3, the liquid ejection head 10 includes a manifold 21, a nozzle plate 22 having a plurality of nozzles, an actuator section 23, a supply pipe 24, a recovery pipe 25, a substrate 26, and a temperature sensor. a thermistor 27;

The manifold 21 is formed inside the manifold 21 , and includes a supply channel for supplying ink supplied from the liquid supply device 11 to the actuator section 23 , and a supply channel for ink passing through the actuator section 23 and being discharged to the liquid supply device 11 . have Note that, for example, when the liquid supply device 11 is configured to have the actuator section 23 or a temperature control device that adjusts the temperature of the ink with temperature control water, the manifold 21 is provided with a channel for temperature control water. good too.

The nozzle plate 22 is formed in, for example, a rectangular plate shape and fixed to the actuator section 23 . The nozzle plate 22 has a plurality of nozzle rows in which a plurality of nozzles are arranged in one direction.

The actuator section 23 is arranged opposite to the print-side surface of the nozzle plate 22 . Actuator section 23 is fixed to manifold 21 . A predetermined flow path including, for example, a plurality of pressure chambers communicating with the nozzles of the nozzle plate 22 and a common chamber communicating with the plurality of pressure chambers is formed inside the actuator section 23 . The actuator section 23 comprises an actuator 231 facing each pressure chamber. The actuator 231 may have, for example, a piezoelectric element in which a groove forming the pressure chamber is formed, or may have a vibration plate forming the pressure chamber and a piezoelectric element for displacing the vibration plate. may For example, the piezoelectric element is made of a piezoelectric ceramic material such as PZT (lead zirconate titanate). The actuator 231 has an electrode formed on the piezoelectric element, and this electrode is electrically connected to the substrate 26 . Various configurations can be applied to the actuator 231 as long as the actuator 231 is electrically connected to the substrate 26 and driven by a drive signal output from the substrate 26 .

The supply pipe 24 and the recovery pipe 25 are provided in the manifold 21, for example. The supply pipe 24 and the recovery pipe 25 are connected to the liquid supply device 11 . The supply pipe 24 and the collection pipe 25 comprise pipes constructed of metal or other thermally conductive material and tubes, eg PTFE tubes, covering the outer surface of the pipes. The manifold 21 , the actuator section 23 , the supply pipe 24 and the recovery pipe 25 form a flow path for ink supplied from the liquid supply device 11 inside the liquid ejection head 10 .

As shown in FIG. 1, substrate 26 is connected to actuator 231 of actuator section 23 . Also, the board 26 is connected to the control board 18 via a harness 31 or the like. For example, one substrate 26 or a plurality of substrates 26 are provided for one actuator 231 . In the example of the liquid ejection head 10 shown in FIG. 3 of this embodiment, four nozzle rows are provided, four actuators 231 corresponding to each nozzle row are provided, and four substrates 26 corresponding to each actuator 231 are provided. Here is an example of one provided.

The board 26 has one end connected to the actuator 231 of the actuator section 23 and the other end connected to the control board 18 via the harness 31 . As shown in FIGS. 3 to 5, the substrate 26 includes, for example, a wiring film 261, a driver IC 262 mounted on the wiring film 261, and a multilayer substrate 263 mounted on the wiring film 261. FIG.

The substrate 26 applies a drive voltage generated by the driver IC 262 to the actuator 231 to drive the actuator 231, increase or decrease the volume of the pressure chamber, and eject droplets from the nozzle.

The wiring film 261 is a film substrate having a wiring pattern formed in a so-called film shape and made of a metal material with high thermal conductivity, such as copper. The wiring film 261 is, for example, a COF (Chip on Film) on which the driver IC 262 is mounted. One or more wiring films 261 are provided for one actuator 231, for example. In this embodiment, an example in which one wiring film 261 is provided for one actuator 231 will be described.

The driver IC 262 is electrically connected through the wiring film 261 to the wiring pattern formed in the pressure chamber. The driver IC 262 is a heating element that generates heat. The driver IC 262 is mounted on the outer surface of the wiring film 261, for example.

One driver IC 262 is provided for one wiring film 261 . A plurality of driver ICs 262 may be provided to drive one actuator 231, and these plurality of driver ICs 262 may be provided on one wiring film 261 to form a driver IC array.

A multilayer substrate 263 is a head substrate connected to the driver IC 262 . The multilayer board 263 is, for example, a printed wiring board. The multilayer board 263 is a PWA (Printing Wiring Assembly) on which various electronic components and connectors are mounted. The multilayer substrate 263 is formed in a rectangular plate shape, and one end of the wiring film 261 is mounted on one side of one main surface. A mounting region B in which the wiring film 261 of the multilayer substrate 263 is mounted is formed in a rectangular shape elongated in one direction along the extending direction of one side of the multilayer substrate 263 . Moreover, the multilayer substrate 263 has a solid pattern 265 provided therein and a through hole 266 that is continuous with the solid pattern 265 . The multilayer board 263 also has a first connector 267 mounted on a portion of the outer surface.

The solid pattern 265 is, for example, a pattern made of a metal material with high thermal conductivity, such as copper. The solid pattern 265 is formed, for example, in a rectangular shape with a predetermined length and width formed inside the multilayer substrate 263 . The solid pattern 265 is provided on the multilayer substrate 263 for temperature propagation to transfer the heat of the driver IC 262 , which has been transferred from the wiring film 261 to the substrate layer 30 , to the through holes 266 .

The solid pattern 265 is provided, for example, to face the mounting region B provided on the multilayer substrate 263 with the outermost substrate layer 30 of the plurality of substrate layers 30 constituting the multilayer substrate 263 interposed therebetween. The solid pattern 265 is formed between the opposing principal surfaces of the two substrate layers 30 on the outer layer side among the plurality of substrate layers 30 .

For example, the solid pattern 265 is formed in the same shape as the mounting region B, and arranged at a position where the plurality of substrate layers 30 overlap in the stacking direction. In other words, the shape and area of the solid pattern 265 are the same as or approximately the same as the shape and area of the mounting region B, and the mounting region B and the solid pattern 265 are formed into a plurality of layers with the outermost substrate layer 30 interposed therebetween. are arranged side by side in the stacking direction of the substrate layers 30 of the . As a specific example, the solid pattern 265 is the main surface of the substrate layer 30 immediately below the substrate layer 30 on which the mounting area B is provided, and faces the mounting area B in the stacking direction of the plurality of substrate layers 30. placed in the area.

The through hole 266 has a metal film formed of a metal material with high thermal conductivity, such as copper, by plating or the like on the inner surface. Through hole 266 is continuous with solid pattern 265 . More specifically, the metal film of through hole 266 is continuous with solid pattern 265 . For example, the metal film of the through hole 266 and the solid pattern 265 are made of the same material.

One end of a harness 31 for connecting the control board 18 and the multilayer board 263 is inserted into the first connector 267 . The first connector 267 fixes one end of the harness 31 .

Specific examples of the multilayer substrate 263 of this embodiment will be described below. As shown in FIGS. 4 and 5, the multilayer substrate 263 has, for example, multiple substrate layers 30 . In this embodiment, the multilayer substrate 263 is formed by laminating six substrate layers 30 . The multiple substrate layers 30 are made of, for example, the same material. The substrate layer 30 is preferably made of, for example, a material with high thermal conductivity. In the following description, the layer on which the wiring film 261 of the multilayer substrate 263 is mounted is referred to as the first substrate layer (first layer) 301, and the first substrate layer 301 and the second substrate layer (second layer) are sequentially arranged from the stacking direction. 302 , third substrate layer 303 , fourth substrate layer 304 , fifth substrate layer 305 and sixth substrate layer 306 .

As shown in FIG. 5, the first substrate layer 301 to the sixth substrate layer 306 are bonded together, for example. For example, wiring patterns are formed on the first to sixth substrate layers 301 to 306, respectively. The first substrate layer 301 and the sixth substrate layer 306 are the outermost layers of the multilayer substrate 263 . The first substrate layer 301 has a mounting area B for the wiring film 261 on its outer surface. Here, the outer surface of the first substrate layer 301 is the main surface of the first substrate layer 301 opposite to the main surface bonded to the second substrate layer 302 . A through-hole 266 is formed in the first substrate layer 301 so as to extend through both main surfaces.

A solid pattern 265 is formed between the first substrate layer 301 and the second substrate layer 302 . In other words, one of the first substrate layer 301 and the second substrate layer 302 has the solid pattern 265 formed on the opposing main surface of the first substrate layer 301 and the second substrate layer 302 . In the example of this embodiment, the second substrate layer 302 has a solid pattern 265 on the main surface of the second substrate layer 302 facing the first substrate layer 301 .

The wiring film 261 , the driver IC 262 and the multilayer substrate 263 of the substrate 26 constitute a head driving circuit (driving circuit) for driving the liquid ejection head 10 .

The thermistor 27 is a temperature sensor. The thermistor 27 is provided on the substrate 26 and near the through hole 266 .

The thermistor 27 is a chip component and directly mounted on the board 26 . Thermistor 27 detects the temperature of the metal film in through hole 266 . The thermistor 27 is electrically connected to the first connector 267 by a wiring pattern. The thermistor 27 outputs a signal corresponding to the detected temperature to the control board 18 via the harness 31 connected to the first connector 267 .

The harness 31 is, for example, a strip-shaped wiring board having flexibility and a certain width. The harness 31 is a so-called flexible cable. The harness 31 includes a plurality of signal lines, which are wiring patterns extending along the longitudinal direction of the harness 31 . The harness 31 is, for example, FPC (Flexible printed circuits).

The liquid supply device 11 includes, for example, an ink tank 14, a pipe line 15, and a pump 16.

The ink tank 14 is a liquid containing portion that contains liquid such as ink to be supplied to the liquid ejection head 10 . The ink tank 14 is connected to the liquid ejection head 10 via a conduit 15 . The ink tank 14 is equipped with a temperature control device composed of, for example, radiation fins, a heater, a heat exchange module, and the like. The temperature control device heats or cools the ink in the ink tank 14 to adjust the temperature of the ink.

The conduit 15 forms a flow path passing through the liquid ejection head 10 and the ink tank 14 . The pipeline 15 includes piping and tubes.

A pump 16 is provided in the conduit 15 . The pump 16 supplies the liquid from the ink tank 14 to the liquid ejection head 10 via the conduit 15 by supplying the liquid to the secondary side. Pump 16 is, for example, a piezoelectric pump. The pump 16 is controlled by a processor 35 connected to a drive circuit by wiring and provided on the control board 18 . The pump 16 sends the liquid in the conduit 15 to the liquid ejection head 10 through the filter.

The interface 17 includes a power source 171 , a display device 172 and an input device 173 . The interface 17 is connected to a processor 35 as a controller. The interface 17 instructs the processor 35 to perform various operations as the user operates the input device 173 . Further, the interface 17 displays various information and images on the display device under the control of the processor 35 of the control board 18, for example.

The control board 18 is a control device. As shown in FIG. 2, the control board 18 includes a processor 35 that is a control unit that controls the operation of each unit, a memory 36 that stores programs and various data, and analog data (voltage values) as digital data (bit data). ), and an AD conversion unit 37 that is a circuit for converting into . In addition, the control board 18 includes each control circuit and each drive circuit for controlling and driving each element.

The control board 18 also includes a second connector 41 mounted at a predetermined portion. The second connector 41 inserts and fixes the other end of the harness 31 for connection with the board 26 .

The processor 35 includes, for example, a CPU (Central Processing Unit) and corresponds to the central portion of the control unit. The processor 35 controls each part of the liquid ejecting apparatus 1 to implement various functions of the liquid ejecting apparatus 1 according to an operating system and application programs.

The processor 35 controls a head driving circuit composed of the driver IC 262 of the liquid ejection head 10 . The processor 35 is connected to various drive mechanisms, and controls the operation of each part of the liquid ejection device 1 via each control circuit and drive circuit such as the AD converter 37, the liquid ejection head 10, and the head power supply circuit. The processor 35 also executes control processing based on a control program recorded in the memory 36 in advance. For example, the processor 35 controls printing operations by controlling the operations of the liquid ejection head 10 and the pump 16 . The processor 35 applies drive voltage to the electrodes of the actuator 231 via the driver IC 262 . When a driving voltage is applied to the electrodes, the actuator deforms and ejects the liquid in the pressure chamber from the nozzle.

In addition, the processor 35 performs error determination processing for temperature abnormality based on the signal output from the thermistor 27 and the threshold value for error determination recorded in advance in the memory 36, and error management processing when an error is determined. conduct. For example, as an error management process, the processor 35 outputs a signal that causes the display device 172 of the interface 17 to display temperature abnormality information.

The memory 36 is, for example, a non-volatile memory and is mounted on the control board 18 . The memory 36 stores various control programs and information necessary for control such as ink circulation operation, ink supply operation, temperature control, liquid surface control, pressure control, and power supply voltage control required for controlling the liquid ejection head 10. Operating conditions are stored.

According to the substrate 26 , the liquid ejection head 10 and the liquid ejection apparatus 1 configured as described above, the wiring film is formed on the mounting area B on the outer surface of the outermost substrate layer 30 (first substrate layer 301 ) of the multilayer substrate 263 . H.261 is implemented. Further, in the multilayer substrate 263, a solid pattern 265 is provided between the outermost substrate layer 30 (first substrate layer 301) where the mounting region B is provided and the substrate layer 30 (second substrate layer 302) adjacent to the outermost layer. is provided. A through hole 266 formed in the outermost substrate layer 30 is connected to the solid pattern 265 . Therefore, the temperature of the driver IC 262 can be detected by detecting the temperature of the through hole 266 with the thermistor 27 .

As a specific example, first, the driver IC 262 may generate heat depending on driving conditions because it generates and outputs waveforms. In addition to the waveform generation and output of the driver IC 262 in the normal state, the driver IC 262 may generate heat even in an abnormal state due to a failure of the driver IC 262 or the like.

In particular, when the driver IC 262 is mounted on the wiring film 261 , there is a problem that the thermistor 27 cannot be mounted on the wiring film 261 . If the driver IC 262 is coated with silicon or the like to dissipate heat to a heat sink or the like, the thermistor 27 cannot be attached directly to the driver IC 262 or the cost increases. In addition, when the wiring film 261 is mounted on the surface of the multilayer substrate 263 (the outer surface of the first substrate layer 301), it is necessary to provide mounted products such as terminals, wiring patterns, and electronic components. It is difficult to provide a solid pattern on the surface.

However, in the substrate 26 of the present embodiment, the solid pattern 265 facing the mounting region B of the wiring film 261 is formed on the first substrate layer 301 which is the surface layer of the multilayer substrate 263 and the second substrate bonded to the first substrate layer 301 . It is provided between the layers 302 and connects the through hole 266 of the first substrate layer 301 and the solid pattern 265 . Thereby, the thermistor 27 can detect heat transferred from the driver IC 262 to the wiring pattern of the wiring film 261 , the substrate layer 30 , the solid pattern 265 and the through hole 266 . Therefore, the liquid ejection device 1 using the substrate 26 can efficiently detect the temperature of the driver IC 262 with the thermistor 27 . Further, since the thermistor 27 detects the heat transferred from the driver IC 262 to the through hole 266 , the liquid ejecting apparatus 1 can improve the accuracy of the measured temperature of the driver IC 262 .

Thereby, the liquid ejection apparatus 1 can always monitor the temperature of the driver IC 262 by the control board 18 . That is, the liquid ejecting apparatus 1 measures the temperature of the driver IC 262 by the thermistor 27 mounted on the multilayer substrate 263 to which the driver IC 262 is connected, without mounting the thermistor 27 on the wiring film 261 on which the driver IC 262 is mounted. be able to. In addition, the liquid ejecting apparatus 1 can grasp the status of the driver IC 262 via the thermistor 27 when heat dissipation from the driver IC 262 is not successful or when the driver IC 262 generates abnormal heat.

In addition, since the solid pattern 265 is provided between the first substrate layer 301 and the second substrate layer 302, which are the outermost layers, the physical distance from the driver IC 262 to the through hole 266 where the thermistor 27 detects the temperature is made as short as possible. can do. Further, the substrate 26 is provided with a solid pattern 265 in an area facing the mounting area B of the wiring film 261 provided on the outer surface of the first substrate layer 301 (the surface of the multilayer substrate 263). Therefore, the heat of the driver IC 262 transmitted through the wiring film 261 can be easily transferred to the solid pattern 265, and the heat capacity of the solid pattern 265 can be minimized. Therefore, the substrate can improve responsiveness to the heat generated by the driver IC 262 in the through hole 266 for detecting heat with the thermistor 27 .

The substrate 26 of the liquid ejecting apparatus 1 according to the above-described embodiment has a multilayer substrate 263 provided with a through hole 266 for detecting the temperature with the thermistor 27, and a wiring film 261 mounting region B provided on the surface of the multilayer substrate 263 and the substrate layer. A solid pattern 265 for temperature propagation facing through 30 is connected to a through hole 266 . As a result, the substrate 26 , the liquid ejection head 10 and the liquid ejection device 1 can efficiently detect the temperature of the driver IC 262 by the thermistor 27 provided on the surface of the multilayer substrate 263 .

In addition, embodiment is not limited to the structure mentioned above. For example, in the above example, a configuration in which one wiring film 261 and driver IC 262 are provided for one actuator 231 has been described, but the present invention is not limited to this. For example, as in another embodiment shown in FIG. 6, the substrate 26 of the liquid ejection head 10 may have a configuration in which a plurality of wiring films 261 and a plurality of driver ICs 262 are provided for one actuator 231 . In the example shown in FIG. 6, the substrate 26 has two wiring films 261 and two driver ICs 262 for one actuator 231 . When such a substrate 26 is used, the mounting regions B for the wiring films 261 provided on the multilayer substrate 263 are provided in the same number as the wiring films 261 . In the example of FIG. 6, the mounting areas B are provided at two locations on the multilayer substrate 263 . In this manner, the substrate 26 may have the same number of mounting areas B, solid patterns 265 , through holes 266 and thermistors 27 as the wiring films 261 .

Also, in the above example, the multilayer substrate 263 has a structure having six substrate layers 30 , but is not limited to this, and may have a structure having two or more substrate layers 30 . Also, in the above example, the solid pattern 265 is provided on the second substrate layer 302 , but is not limited to this, and may be provided on the first substrate layer 301 . However, since the solid pattern 265 is provided in order to detect the temperature of the driver IC 262, the solid pattern 265 is formed between the outermost substrate layer 30 in which the mounting region B of the wiring film 261 provided in the multilayer substrate 263 is provided, and the It is preferably provided between the outermost substrate layer 30 and the substrate layer 30 one level below.

In the above example, the liquid ejection device 1, the liquid ejection head 10, and the substrate 26 are used in an inspection device and an inkjet recording device. It can also be used for manufacturing machines and medical applications. Also, the substrate 26 can be used in various devices as long as it is configured to detect the temperature of a heating element mounted on a film.

The substrate, the liquid ejection head, and the liquid ejection device according to each embodiment configured as described above efficiently detect the temperature of the driver IC by the thermistor provided on the surface of the multilayer substrate in which the through holes and the solid pattern are formed. can do.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

REFERENCE SIGNS LIST 1 liquid ejection device 10 liquid ejection head 11 liquid supply device 14 ink tank 15 pipeline 16 pump 17 interface 18 control board 21 manifold 22 nozzle plate 23 Actuator section 24 Supply pipe 25 Recovery pipe 26 Substrate 27 Thermistor 30 Substrate layer 31 Harness 35 Processor 36 Memory 37 AD converter 41 Second Connector 171 Power supply 172 Display device 173 Input device 231 Actuator 261 Wiring film 262 Driver IC (heating element) 263 Multilayer substrate 265 Solid pattern 266 Through hole 267 First connector 301 First substrate layer (first layer) 302 Second substrate layer (Second layer) 303 Third substrate layer 304 Fourth substrate layer 305 Fifth substrate layer 306... Sixth substrate layer, B... Mounting area.

Claims (5)

a film substrate on which a heating element is mounted;
A multilayer substrate having a first layer to which the film substrate is connected and through holes are formed, and a second layer laminated on the first layer;
A solid pattern formed of a metal material provided between the first layer and the second layer;
a thermistor provided on the multilayer substrate and connected to the solid pattern through the through hole. 2. The substrate of claim 1, wherein the solid pattern is formed on the second layer. The solid pattern has the same shape as the mounting area of the film substrate mounted on the first layer, and is arranged side by side with the mounting area in the stacking direction of the first layer and the second layer. A substrate according to claim 1 or claim 2. A substrate according to any one of claims 1 to 3;
an actuator to which the substrate is connected;
a liquid ejection head. a liquid ejection head according to claim 4;
a control board connected to the board and the thermistor;
A liquid ejection device.