Liquid dispensing head and recording device

Abstract

The system must be able to shut down safely even if an electrical malfunction occurs. [Solution] The liquid discharge head includes a drive means capable of performing at least one of a drive that circulates liquid and a drive that discharges liquid based on a printing signal, and a monitoring means that sets at least one of the drives that circulate liquid and the drive that discharges liquid as a target for monitoring, and monitors at least one of the signal supplied to the target for monitoring and the drive voltage supplied to the target for monitoring based on a predetermined set value, wherein the set value is set to be unrewritable.

Description

Technical Field

[0001] This disclosure relates to the technology of a liquid ejection head that ejects while circulating a liquid.

Background Art

[0002] Conventionally, in the field of inkjet printers, a technique for circulating a liquid (hereinafter also referred to as ink) in a circulation channel communicating with a discharge port is known. Further, in Patent Document 1, a technique of a diagnostic circuit that detects whether a voltage value resulting from the operation of a piezoelectric element or the like is normal in a print head (hereinafter also referred to as a liquid ejection head) that ejects a liquid and diagnoses whether the print head can operate normally is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even if the diagnostic circuit described in Patent Document 1 detects an abnormality in the voltage value and diagnoses whether the liquid ejection head can operate normally, there is a possibility that the set value for detecting the abnormality in the voltage value may be rewritten in the first place. Therefore, there are cases where it is impossible to correctly diagnose whether the liquid ejection head can operate normally. Further, the diagnostic circuit described in Patent Document 1 only electrically connects between two wirings when it diagnoses that the liquid ejection head can operate normally, and there are cases where it does not necessarily lead to the stop of the operation when it cannot operate normally. That is, in the conventional technology as described in Patent Document 1, there are cases where it cannot be safely stopped even if an electrical abnormality occurs.

Means for Solving the Problems

[0005] A liquid discharge head according to one aspect of the present disclosure comprises a drive means capable of performing at least one of a drive for circulating liquid and a drive for discharging liquid based on a printing signal, and a monitoring means that sets at least one of the drives for circulating liquid and the drive for discharging liquid as a target for monitoring, and monitors at least one of the signal supplied to the target for monitoring and the drive voltage supplied to the target for monitoring based on a predetermined set value, wherein the set value is set to be unrewritable. [Effects of the Invention]

[0006] According to this disclosure, even if an electrical malfunction occurs, the system can be safely shut down. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of the liquid dispensing device of the present disclosure according to the first embodiment. [Figure 2] This is an exploded perspective view of the liquid dispensing head of Figure 1 according to the first embodiment. [Figure 3] This is a schematic diagram of the ink circulation unit shown in Figure 2 according to the first embodiment. [Figure 4] This is a schematic diagram of the ink circulation path in which the liquid is circulated by the circulation pump shown in Figure 3 according to the first embodiment. [Figure 5] This figure shows an example of the wiring of the circulation pump in Figure 4 according to the first embodiment. [Figure 6] This is a schematic cross-sectional view of the circulation pump shown in Figure 5 according to the first embodiment. [Figure 7] This is a block diagram of the monitoring system of the liquid discharge head drive unit according to the first embodiment. [Figure 8] This is a block diagram of the monitoring system of the discharge unit according to the first embodiment. [Figure 9] This is a block diagram showing that the monitoring system of the discharge unit according to the first embodiment includes a voltage divider circuit. [Figure 10]This is a block diagram showing the monitoring system of the discharge unit according to the second embodiment, which includes a main signal generation circuit and a peak hold circuit. [Figure 11] This is a block diagram showing the monitoring system of the discharge element unit according to the second embodiment, which includes a main signal generation circuit, a voltage divider circuit, and a peak hold circuit. [Figure 12] This is a block diagram showing the monitoring system of the ink circulation unit according to the third embodiment, which includes a main signal generation circuit and a peak hold circuit. [Figure 13] This is a block diagram showing the monitoring system of the ink circulation unit according to the third embodiment, which includes a main signal generation circuit, a voltage divider circuit, and a peak hold circuit. [Figure 14] This is a block diagram showing the monitoring system of the discharge unit according to the fourth embodiment, which includes a circuit control unit and a boost circuit. [Figure 15] This is a block diagram showing the monitoring system of the discharge unit according to the fourth embodiment, which includes a circuit control unit, a boost circuit, and a voltage divider circuit. [Figure 16] This block diagram shows the monitoring system of the ink circulation unit according to the fifth embodiment, which includes a head information storage means, a circuit control unit, a boost circuit, and an output switching circuit. [Figure 17] This block diagram shows the monitoring system of the ink circulation unit according to the fifth embodiment, which includes a head information recording means, a circuit control unit, a boost circuit, a voltage divider circuit, and an output switching circuit. [Figure 18] This block diagram shows that the monitoring system of the discharge unit according to the sixth embodiment includes a circuit control unit, a boost circuit, and a voltage divider circuit, and the monitoring system of the ink circulation unit includes a circuit control unit, a boost circuit, a voltage divider circuit, and an output switching circuit. [Modes for carrying out the invention]

[0008] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the disclosed matters, and not all combinations of features described in the following embodiments are essential for the solution means of the present disclosure. The same components are denoted by the same reference numerals.

[0009] (Overview) Conventionally, various recording methods have been put into practical use to record an image on a recording medium such as paper. Examples of such recording methods include a thermal transfer method, a wire dot method, a thermal method, and an inkjet method. Among these recording methods, the inkjet method has attracted attention due to various characteristics and is used in a wide range of fields. For example, such characteristics include a low running cost and a suppressed recording sound. In the inkjet method, a recording element substrate provided on a liquid ejection head is driven. An ink ejection port is provided on the surface of the recording element substrate. The ink ejection port is formed by a nozzle member. When the recording element substrate is driven, ink droplets are ejected from the ink ejection port. The liquid ejection head lands the ink droplets at a desired position on the ejection target medium P, whereby the image is recorded on the ejection target medium P.

[0010] An actuator for controlling the ejection of ink is provided at a position corresponding to the ejection port. When the actuator is driven, the ink is ejected onto the ejection target medium P. In order to apply the energy required for this ejection to the ink, it is necessary to supply a high-pressure signal to the actuator.

[0011] In recent years, in the inkjet method, in order to output high-quality printed matter, an ink circulation type recording apparatus that can use special ink according to the ejected medium P has also been demanded. Such an ink circulation type recording apparatus is also provided with a liquid ejection head. Such a liquid ejection head is provided with an ink supply path and a recovery path, and a configuration for obtaining a circulating flow of ink by generating a differential pressure between the ink supply path and the ink recovery path is proposed in Patent Document 1. Patent Document 1 discloses a liquid ejection head having two storage portions for supplying and refluxing ink, a pump (also referred to as an actuator) for transporting ink between the two storage portions, a pressure sensor, and a drive circuit for driving the pump according to the output of the pressure sensor. In such a liquid ejection head, in order to obtain the necessary ink flow rate, it is necessary to supply a high-pressure signal to the pump.

[0012] The voltage and signal serving as drive sources for controlling ink ejection or flow rate as described above are sent from the recording apparatus main body to the liquid ejection head. Such a voltage is a high-pressure drive voltage. Further, such a signal is a control signal for the recording operation by the liquid ejection head. Therefore, when an electrical abnormality occurs in the voltage or signal sent from the recording apparatus main body to the liquid ejection head, it is necessary to appropriately detect it and safely stop it. Patent Document 1 discloses a liquid ejection head provided with an integrated circuit in which a diagnostic circuit for diagnosing whether or not dots satisfying print quality can be formed is mounted.

[0013] However, even in the case of a liquid ejection head provided with the above diagnostic circuit, if the set value set in the integrated circuit is rewritten due to some influence, the diagnostic circuit mounted in the integrated circuit may not be able to make a correct abnormality determination in the first place. Therefore, as a premise for diagnosing whether to safely stop the liquid ejection head, a configuration in which the set value set in the integrated circuit is not rewritten is necessary. Further, the above diagnostic circuit only electrically connects between two wirings when it diagnoses that the liquid ejection head can operate normally, and there are cases where it does not necessarily lead to a stop of operation when it cannot operate normally. That is, even if an electrical abnormality occurs, there are cases where it cannot be safely stopped.

[0014] Therefore, in this disclosure, the liquid dispensing head comprises a driving means and a monitoring means. The driving means can perform a drive to circulate the liquid and a drive to dispense the liquid based on a printing signal. The monitoring means sets the driving means as a monitoring target and monitors at least one of the signal supplied to the monitoring target and the driving voltage supplied to the monitoring target based on a set value. The set value is set to be unrewritable. With such a configuration, rewriting of the set value can be avoided, so it is possible to correctly diagnose whether the liquid dispensing head is able to operate normally. Furthermore, in this disclosure, if the driving voltage exceeds the range defined by the set value, the monitoring means stops supplying at least one of the signal and the driving voltage to the monitoring target. With such a configuration, even if the liquid dispensing head is not able to operate normally, the supply of at least one of the signal and the driving voltage that serve as the driving source for operation is stopped, so it is possible to reliably stop the driving of the liquid dispensing head. Here, to set the setting value to be unrewritable, it is assumed that at least one of hardware setting and software setting is used. For example, the accidental overwriting of setting values ​​can be prevented by using ROM (Read Only Memory) as the storage medium where the setting values ​​are stored. Alternatively, the entire storage medium where the setting values ​​are stored can be covered with a magnetic shield to prevent data corruption due to strong magnetic fields, thereby preventing overwriting or corruption of the setting values. Alternatively, if a switching mechanism for switching between write-protected and write-allowed states is implemented on the board, the overwriting of the setting values ​​can be prevented by setting that switching mechanism to write-protected. Alternatively, the overwriting of the setting values ​​can be prevented by physically disabling the JTAG interface of the FPGA (Field Programmable Gate Array). Alternatively, when using a Windows-based OS (Operating System), the attempt to overwrite the setting values ​​can be prevented altogether by setting a write-protected number in the registry key. Alternatively, the overwriting of the setting values ​​can be prevented by setting the file attribute of the logical file containing the setting values ​​to write-protected with administrator privileges.Alternatively, the modification of the setting values ​​may be avoided by requiring a password when writing the logical file containing the setting values. The embodiment is not particularly limited as long as the configuration makes it impossible to modify the setting values. Further details of this disclosure will be described below.

[0015] (First Embodiment) Figure 1 is a schematic diagram of a liquid dispensing device 50 of the present disclosure according to a first embodiment. Figure 1(a) is a schematic perspective view of the liquid dispensing device 50. Figure 1(b) is a block diagram of the control system of the liquid dispensing device 50. The liquid dispensing device 50 comprises a liquid dispensing head 1 and transport rollers 55, 56, 57, and 58. The liquid dispensing head 1 is scannable in a direction X that intersects the transport direction Y of the medium to be dispensed P. In the example shown in Figure 1(a), the liquid dispensing head 1 is mounted on a carriage 53. The carriage 53 reciprocates along a guide axis 51 in the main scanning direction (also referred to as direction X). The transport rollers 55, 56, 57, and 58 transport the medium to be dispensed P in a sub-scanning direction (also referred to as transport direction Y) that intersects (orthogonal in this embodiment) the main scanning direction. In other words, the liquid ejection device 50 constitutes a serial-type inkjet liquid ejection device by scanning the liquid ejection head 1 in direction X and ejecting liquid from the liquid ejection head 1 onto the ejection medium P being transported in the transport direction Y. However, the application of this disclosure is not limited to serial-type inkjet liquid ejection devices. This disclosure can also be applied to a page-wide type inkjet liquid ejection device that ejects liquid onto the ejection medium P being transported in the transport direction Y by using a line head (page-wide type head) that is long in the page width direction of the ejection medium P. In Figure 1(a), direction Z indicates the vertical direction. That is, direction Z is the direction that intersects (orthogonal in this embodiment) the XY plane specified by direction X and transport direction Y. In the following description, direction X, transport direction Y, and direction Z will be used with the same meaning as described above.

[0016] The liquid ejection head 1 is capable of ejecting four types of ink: black (K), cyan (C), magenta (M), and yellow (Y). The liquid ejection head 1 can eject a full-color image using these four types of ink. However, the inks that can be ejected from the liquid ejection head 1 are not limited to the above four types. For example, this disclosure is also applicable to a liquid ejection head 1 for ejecting other types of ink, such as spot color inks. That is, the type and number of inks ejected from the liquid ejection head 1 are not limited. Furthermore, a cap member may be positioned to cover the face surface of the liquid ejection head 1, away from the transport path of the ejection medium P. When not performing a recording operation, the cap member moves relative to the position that covers the face surface of the liquid ejection head 1. This operation prevents the liquid ejection port of the liquid ejection head 1 from drying out, or allows for suction operations for filling or restoring.

[0017] In the example shown in Figure 1(a), an ink circulation unit 54 is mounted on the liquid ejection head 1. A guide 59 housing four ink supply tubes (liquid passages) is attached to the ink circulation unit 54. In addition to the ink supply tubes, the guide 59 also houses the electrical wiring and air piping necessary for liquid ejection. Furthermore, an ink tank 2 and a pump 21 are provided on the main body (not shown) side of the liquid ejection device 50. The ink tank 2 stores ink. The ink stored in the ink tank 2 is supplied to the ink circulation unit 54 via the four ink supply tubes by the driving force of the pump 21. The liquid ejection head 1 may be provided integrally with the ink circulation unit 54 and configured to be removable or attachable to the carriage 53. Alternatively, the ink circulation unit 54 may be provided integrally with the carriage 53, and only the ink circulation unit 54 may be configured to be removable or attachable. In the following description, an example in which the liquid ejection head 1 includes the ink circulation unit 54 will be described.

[0018] The CPU 400 in Figure 1(b) performs various controls on the liquid dispensing device 50. ROM 401 stores programs such as processing procedures. The CPU 400 retrieves these programs from ROM 401. Based on the retrieved programs, the CPU 400 controls the liquid dispensing device 50. The CPU 400 uses RAM 402 as a work area for executing the programs retrieved from ROM 401. The CPU 400 retrieves image data from a host device 500 located outside the liquid dispensing device 50. Based on the retrieved image data, the CPU 400 controls the head driver 1A. The head driver 1A controls the dispensing of liquid by the liquid dispensing head 1. The CPU 400 also controls the motor driver 403A. The motor driver 403A controls the carriage motor 403. The carriage motor 403 moves the carriage 53 along the X direction. The CPU 400 also controls the motor driver 404A. The motor driver 404A controls the transport motor 404. The transport motor 404 controls the transport rollers 55, 56, 57, and 58. The transport rollers 55, 56, 57, and 58 transport the discharge medium P along the transport direction Y.

[0019] (Liquid dispensing head 1) Figure 2 is an exploded perspective view of the liquid discharge head 1 of Figure 1 according to the first embodiment. The liquid discharge head 1 comprises a flow channel member 110, an ink circulation unit 54, and a discharge unit 300. At least a portion of the ink circulation unit 54 is housed in the flow channel member 110 and connected to the flow channel member 110. The discharge unit 300 is provided at the bottom of the flow channel member 110 and connected to the flow channel member 110. Specifically, the ink circulation unit 54 consists of ink circulation units 54m, 54y, 54k, and 54c, each corresponding to a different ink. When not specifically distinguishing between the ink circulation units 54m, 54y, 54k, and 54c, they are referred to as the ink circulation unit 54. Each ink circulation unit 54 is housed in and connected to the flow channel member 110. Each ink circulation unit 54 and the flow channel member 110 may be connected by screw fastening with a sealing member sandwiched between them. Alternatively, each ink circulation unit 54 and the flow path member 110 may be connected by welding. The flow path member 110 has a surface on which four joints 200 are provided, each connected to one of the four ink supply tubes corresponding to the four types of ink. In other words, a separate ink supply path is provided for each type of ink. Specifically, each of the ink circulation units 54m, 54y, 54k, and 54c is connected to the respective ink supply tubes corresponding to each ink from the main body side of the liquid discharge device 50 via its respective joint 200. Each ink supplied from the respective corresponding ink supply tube is supplied to each ink circulation unit 54 via the joint 200. Each ink supplied to each ink circulation unit 54 is supplied to the discharge unit 300 via the flow path member 110.

[0020] The ejection unit 300 comprises an ejection element substrate 310, a support member 320, an electrical wiring board 330, and a cover member 340. The ejection element substrate 310 and the electrical wiring board 330 are bonded and fixed to the support member 320. The cover member 340 is bonded and joined to cover the surface of the electrical wiring board 330. The portion of the cover member 340 corresponding to the ejection element substrate 310 is open. The ejection element substrate 310 has an actuator for ejecting ink. Therefore, the ejection element substrate 310 can eject liquid into the medium P to be ejected, which passes below the liquid ejection head 1. The ejection unit 300 and the flow path member 110 are bonded together using adhesive. Alternatively, the ejection unit 300 and the flow path member 110 may be fixed together by screwing in a sealing member.

[0021] The ejection element substrate 310 and the electrical wiring board 330 are electrically connected by wire bonding. The electrical wiring board 330 sends various electrical signals to the ejection element substrate 310. The ejection element substrate 310 ejects liquid according to the various electrical signals from the electrical wiring board 330, using the drive voltage supplied from the head driver 1A. Details of the various electrical signals will be described later. Note that the ejection element substrate 310 and the electrical wiring board 330 may also be electrically connected by flying lead bonding or the like.

[0022] A contact surface is provided on the side of the flow channel member 110 opposite to the side where the joint 200 is provided. The head board 210 is connected to the contact surface. The head board 210 receives electrical signals from the main body of the liquid dispensing device 50. The head board 210 and the electrical wiring board 330 are electrically connected. The electrical signals received by the head board 210 are sent to the dispensing element board 310 via the electrical wiring board 330. The head board 210 and the flow channel member 110 may be fixed by crimping, by adhesive, or by double-sided tape. The head board 210 and the carriage board 220 may be electrically connected by ACF (Antisotropic Conductive Film) bonding. Alternatively, the head board 210 and the electrical wiring board 330 may be electrically connected by wire bonding. Alternatively, the head board 210 and the electrical wiring board 330 may be electrically connected by flying lead bonding.

[0023] (Ink circulation path) Figure 3 is a schematic diagram of the ink circulation unit 54 of Figure 2 according to the first embodiment. One ink circulation unit 54 is provided for each color. The ink circulation unit 54 comprises a first pressure control mechanism 24, a second pressure control mechanism 28, a filter 23, and a circulation pump 27. Figure 4 is a schematic diagram of the ink circulation path in which the liquid is circulated by the circulation pump 27 of Figure 3 according to the first embodiment. The ink circulation path in Figure 4 is for one color. The liquid discharge head 1 is provided with the ink circulation path in Figure 4 for each ink. The ink tank 2 and the pump 21 are provided on the main body side of the liquid discharge device 50. The first pressure control mechanism 24 comprises a valve chamber 25 and a pressure control chamber 26. The valve chamber 25 and the pressure control chamber 26 are in communication via a valve (not shown). The second pressure control mechanism 28 comprises a valve chamber 29 and a pressure control chamber 30. The valve chamber 29 and the pressure control chamber 30 are in communication via a valve (not shown). The circulation pump 27 and the pressure control chamber 26 are connected via a pump outlet passage 78. The pressure control chamber 26 and the flow path member 110 are connected via a supply passage 75. A portion of the flow path member 110 may constitute the supply passage 75. The flow path member 110 and the pressure control chamber 30 are connected via a recovery passage 76. The position of the flow path member 110 may constitute the recovery passage 76. The pressure control chamber 30 and the circulation pump 27 are connected via a pump inlet passage 77. In other words, an ink circulation path is formed consisting of the pressure control chamber 26, the supply passage 75, the flow path member 110, the recovery passage 76, the pressure control chamber 30, the pump inlet passage 77, the circulation pump 27, and the pump outlet passage 78. Ink can circulate through this ink circulation path. Next, the details of the circulation pump 27 will be described, and then the flow of ink circulating through the ink circulation path will be described.

[0024] (Drive mechanism of circulation pump 27) Figure 5 shows an example of the wiring of the circulation pump 27 in Figure 4 according to the first embodiment. The main board 230 is provided on the body of the liquid discharge device 50. The CPU 400 is mounted on the main board 230. The carriage board 220 is provided on the carriage 53. The main board 230 and the carriage board 220 are connected via an FFC (Flexible Flat Cable). A drive signal is sent from the CPU 400 to the carriage board 220 via the FFC. The carriage board 220 and the head board 210 are connected via an electrical connection part 212. A pump control signal and a pump drive reference voltage are sent from the carriage board 220 to the head board 210 via the electrical connection part 212. The head board 210 and the circulation pump 27 are connected via a harness 211. The harness 211 consists of a cable assembly including a first wiring 211a and a second wiring 211b. A pump drive signal, generated based on the pump control signal and the pump drive voltage generated from the pump drive reference voltage, is output to the circulation pump 27 via the harness 211. Based on the pump drive signal, the circulation pump 27 is driven and the liquid is circulated. In the following explanation, it is assumed that the head board 210, carriage board 220, electrical connection part 212, electrical wiring board 330, and discharge element board 310 are each connected to ground. Furthermore, the potential difference between the reference potential, which is the potential of ground, and the potential of the comparison target will be explained as voltage. For example, the voltage of the pump control signal represents the voltage difference between the potential of the pump control signal and the reference potential.

[0025] (Configuration of circulation pump 27) Figure 6 is a schematic cross-sectional view of the circulation pump 27 of Figure 5 according to the first embodiment. The first electrode 272 is connected to the first wiring 211a via an electrical connecting member 277a. The second electrode 274 is connected to the second wiring 211b via an electrical connecting member 277b. In this embodiment, the electrical connecting members 277a and 277b are solder, but are not limited to this. Conductive materials such as gold bushings may be used for the electrical connecting members 277a and 277b. A piezoelectric element 273 is provided between the first electrode 272 and the second electrode 274. One surface of the piezoelectric element 273 is in contact with the first electrode 272. The other surface of the piezoelectric element 273 is in contact with the second electrode 274. One surface of the second electrode 274 is in contact with the piezoelectric element 273, and the other surface is in contact with the diaphragm 275. In other words, a laminate is formed by stacking the first electrode 272, the piezoelectric element 273, the second electrode 274, and the diaphragm 275 in that order. The pump housing 271 is provided so as to cover this laminate. In addition, a diaphragm unit 276 is provided on the side of the diaphragm 275 opposite to the side on which this laminate is formed. The diaphragm unit 276 comprises a diaphragm unit housing 276a, a valve body 276b, and a valve body 276c. The diaphragm unit housing 276a is made of a concave-shaped housing. A pressure chamber 276d is formed when the concave edge of the diaphragm unit housing 276a and the edge of the diaphragm 275 are fixed in contact with each other. Valve bodies 276b and 276c are each installed at a fixed distance from each other at the bottom of the diaphragm unit housing 276a, so as to be able to move freely in response to the outflow of liquid from the pressure chamber 276d and the inflow of liquid into the pressure chamber 276d, and function as valves. Opposite valve body 276b is the pump outlet passage 78 shown in Figure 4. Opposite valve body 276c is the pump inlet passage 77 shown in Figure 4. Next, the flow of ink will be explained using Figure 4.

[0026] (Ink flow) Returning to Figure 4, the pump 21 in Figure 4 pressurizes and supplies ink stored in the ink tank 2 to the liquid discharge head 1. The filter 23 removes dust contained in the pressurized ink supplied from the pump 21. The ink from which dust has been removed by the filter 23 is supplied to the valve chamber 25 of the first pressure control mechanism 24. As the ink supplied to the valve chamber 25 flows into the pressure control chamber 26, its pressure is controlled by the circulation pump 27. Next, the details of the pressure control by the circulation pump 27 will be explained using Figure 6.

[0027] By creating a potential difference in the piezoelectric element 273 in Figure 6, the volume inside the pressure chamber 276d is changed, causing pressure fluctuations inside the pressure chamber 276d. Due to the pressure fluctuations inside the pressure chamber 276d, the two valve bodies 276b and 276c move alternately, sending ink, and the circulation pump 27 functions as a piezoelectric diaphragm pump. The circulation pump 27 is driven to send ink with the pump inlet passage 77 on the downstream side and the pump outlet passage 78 on the upstream side. Now, let's return to Figure 4. Driven by the circulation pump 27 in Figure 4, the ink whose pressure is controlled inside the pressure control chamber 26 is supplied to the supply passage 75 and the bypass passage 79. The supply passage 75 supplies ink to the flow path member 110. The flow path member 110 supplies the ink supplied from the supply passage 75 to the discharge unit 300. The ink supplied to the discharge unit 300 is supplied to the discharge element substrate 310 inside the discharge unit 300. An ink discharge element is provided on the discharge element substrate 310. Ink supplied to the discharge element substrate 310 passes through the discharge element and is then discharged into the recovery channel 76. The discharge element comprises an energy generating element, a pressure chamber, and a discharge port. Ink that has passed through the pressure chamber inside the discharge element and been discharged into the recovery channel 76 is supplied to the pressure control chamber 30. In addition, ink supplied to the valve chamber 29 via the bypass channel 79 is supplied to the pressure control chamber 30, which is connected to the valve chamber 29 via a valve. Thus, ink is supplied to the pressure control chamber 30 from both the recovery channel 76 and the bypass channel 79. The ink supplied to the pressure control chamber 30 is supplied to the circulation pump 27 via the pump inlet channel 77. The ink supplied to the circulation pump 27 is supplied to the pressure control chamber 26 via the pump outlet channel 78. In this way, the ink is circulated by the circulation pump 27, passing through the discharge element formed on the discharge element substrate 310. This constitutes an ink circulation path in which the ink circulates. With this configuration, it is possible to suppress the thickening of the ink in the ejection element. The ink circulation path is not limited to a configuration that passes through the ejection element. For example, the ink circulation path may be configured to circulate the ink inside the ejection unit 300, as long as it is effective in suppressing the thickening of the ink in the ejection element. Next, the inflow and outflow of ink will be explained using the following three use cases with reference to Figure 6.

[0028] (Use Case 1) This section describes a use case in which ink flows into the pressure chamber 276d. Assume that a potential difference is generated from the second electrode 274 towards the first electrode 272, causing the piezoelectric element 273 and the diaphragm 275 to be displaced in a direction that expands the pressure chamber 276d. In this scenario, the valve body 276c opens, and ink flows into the pressure chamber 276d from the pump inlet passage 77.

[0029] (Use Case 2) Let's describe a use case where ink flows out from the pressure chamber 276d. Assume that a potential difference is generated from the first electrode 272 to the second electrode 274, causing the piezoelectric element 273 and the diaphragm 275 to be displaced in a direction that contracts the pressure chamber 276d. In this scenario, the valve body 276b opens, and ink flows out from the pressure chamber 276d into the pump outlet channel 78.

[0030] (Use Case 3) This section describes a use case in which neither ink flows into nor out of the pressure chamber 276d. Assume that there is no potential difference between the first electrode 272 and the second electrode 274. In this scenario, the piezoelectric element 273 and the diaphragm 275 do not displace into the pressure chamber 276d in either an expanding or contracting direction. Therefore, no ink flows into or out of the diaphragm unit 276.

[0031] Specifically, by periodically changing the potential difference between the first electrode 272 and the second electrode 274, the circulation pump 27 causes ink to flow in through the pump inlet passage 77 and to flow out through the pump outlet passage 78. Next, a process for driving the liquid discharge head 1 based on a control signal and a drive voltage, and diagnosing whether the liquid discharge head 1 is able to operate normally, will be described.

[0032] Figure 7 is a block diagram of the monitoring system of the liquid ejection head drive unit 810 according to the first embodiment. The liquid ejection head drive unit 810 is a general term for a unit provided inside the liquid ejection head 1 that can be driven by supplying at least one of voltage and / or a signal. The liquid ejection head drive unit 810 performs a drive to circulate the liquid and a drive to eject the liquid based on a printing signal. The drive to circulate the liquid can be realized, for example, by the ink circulation unit 54. The drive to eject the liquid based on a printing signal can be realized, for example, by the ejection unit 300. The recording device in Figure 7 corresponds to the liquid ejection device 50 described above. The recording device in the following description also corresponds to the liquid ejection device 50 described above. The recording device includes a CPU 400, a power supply unit 410, a main unit output terminal 451, and a main unit input terminal. The CPU 400, power supply unit 410, main unit output terminal 451, and main unit input terminal are included in the main body of the liquid ejection device 50 in Figure 1. The liquid discharge head 1 includes a head input terminal 452, a monitoring unit 903, a head output terminal, a head drive signal output terminal 814, and a liquid discharge head drive unit 810. The liquid discharge head drive unit 810 includes a head drive signal input terminal 815 and a liquid discharge head drive unit 816.

[0033] The host device 500 and the external power supply 510 are located outside the recording device. A print signal 601, as image data, is input from the host device 500 to the CPU 400 of the recording device. Meanwhile, a power supply voltage 602 is supplied from the external power supply 510 to the power supply device 410. Upon receiving the print signal 601 from the host device 500, the CPU 400 activates a power control signal 603 to the power supply device 410. In this embodiment, the power control signal 603 is assumed to be high active. That is, it is assumed that the power supply device 410 is set to operate when the power control signal 603 is high. Specifically, when the signal potential of the power control signal 603 transitions from 0V to 3.3V, the power supply device 410 outputs a head drive voltage 801 to the main output terminal 451. Upon receiving the print signal 601 from the host device 500, the CPU 400 outputs a head control signal 804 to the main output terminal 451. The main unit output terminal 451 outputs the head drive voltage 801 and the head control signal 804 to the head input terminal 452. A monitoring unit 903 is provided between the head input terminal 452 and the head drive signal output terminal 814. The head input terminal 452 and the monitoring unit 903 are provided on the head board 210. The head board 210 and the ejection element board 310 are electrically connected via the electrical wiring board 330. Therefore, the head input terminal 452 and the monitoring unit 903 are electrically connected to the head drive signal output terminal 814 via the electrical wiring board 330. The head drive signal output terminal 814 and the head drive signal input terminal 815 are electrically connected by wire bonding or the like.

[0034] (Monitoring Department 903) The monitoring unit 903 sets the liquid discharge head drive unit 810 as the target to be monitored and monitors at least one of the signal supplied to the target and the drive voltage supplied to the target based on a set value. The set value is set to be unrewritable. For example, the monitoring unit 903 receives the discharge element control signal 904 as a head control signal 804, which is a control signal to the liquid discharge head drive unit 810. The monitoring unit 903 diagnoses whether the discharge element control signal 904 is abnormal or not. For example, a signal potential upper limit value is set as the set value, which is the upper limit value of the potential of the discharge element control signal 904. If the discharge element control signal 904 exceeds the signal potential upper limit value, the monitoring unit 903 diagnoses that the discharge element control signal 904 is abnormal and is a signal that may damage the liquid discharge head drive unit 816 (for example, the discharge element substrate 310). On the other hand, if the monitoring unit 903 diagnoses that the discharge element control signal 904 is not abnormal, it permits the transmission of the head control signal to the liquid discharge head drive unit 816. Furthermore, the monitoring unit 903 monitors the head drive voltage 801 supplied from the power supply unit 410 as the test voltage 902. The monitoring unit 903 monitors whether the test voltage 902 is within a predetermined voltage range. For example, a lower limit voltage value and an upper limit voltage value are set as the predetermined voltage range. Here, the set value is at least one threshold value, and in the above example, an example of two threshold values, a lower limit voltage value and an upper limit voltage value, is shown as the set value. Based on such set values, the monitoring unit 903 monitors the test voltage 902. If the monitoring unit 903 diagnoses that the head control signal 804 or the test voltage 902 is abnormal, it sends an error communication signal 905 to the CPU 400. When the CPU 400 receives the error communication signal 905, it stops the transmission of the head control signal 804 and the head drive voltage 801. This operation prevents damage to the liquid discharge head drive unit 816. To indicate that the monitoring unit 903 is performing its monitoring function correctly, the monitoring unit 903 continuously sends an operation confirmation signal 906 to the CPU 400. Therefore, if a malfunction or other abnormality occurs in the monitoring unit 903, the operation confirmation signal 906 will not be sent to the CPU 400.Therefore, if the CPU 400 cannot confirm the output of the operation confirmation signal 906 while monitoring based on the set value continues, it may diagnose that there is an abnormality in the liquid discharge head 1 and stop the operation of the recording device.

[0035] In this embodiment, an FPGA (Field Programmable Gate Array) is used for the monitoring unit 903. An FPGA is a general-purpose logic device. Furthermore, an FPGA is a highly versatile IC (Integrated Circuit) that balances processing power and cost. However, the implementation form of the monitoring unit 903 is not particularly limited as long as it can realize the functions described above. For example, the monitoring unit 903 may be a circuit formed of discrete elements, or a PLD (Programmable Logic Device), microcontroller, ASIC, etc. When a general-purpose logic device such as an FPGA is used, there is a risk that monitoring may not be able to be performed properly if the setting values ​​written to the internal registers are overwritten due to some influence. For this reason, it is desirable that the setting values ​​of the registers in the monitoring unit 903 are locked so that they cannot be overwritten.

[0036] From the above description, the liquid discharge head 1 comprises a drive means and a monitoring means. The drive means can perform at least one of the drives that circulate the liquid and the drives that discharge the liquid based on a printing signal. The monitoring means sets at least one of the drives that circulate the liquid and the drives that circulate the liquid as the target to be monitored, and monitors at least one of the signal supplied to the target to be monitored and the drive voltage supplied to the target to be monitored based on a predetermined set value. This set value is set to be unrewritable. With this configuration, rewriting of the set value can be avoided, so it is possible to correctly diagnose whether the liquid discharge head is operating normally or not. Therefore, even if an electrical abnormality occurs, it can be safely shut down.

[0037] Furthermore, the monitoring means may stop supplying at least one of the signal and the drive voltage to the monitored object if the drive voltage exceeds a range defined by a set value. With this configuration, it is possible to stop the driving of the monitored object if the drive voltage exceeds a set value. For example, even if the drive voltage exceeds the withstand voltage of the monitored object, it is possible to stop the driving of the driving means.

[0038] Furthermore, the monitoring means may output an operation confirmation signal to the outside to indicate that monitoring has been performed while monitoring continues based on the set value. With this configuration, if the operation confirmation signal stops being output, it means that monitoring was not performed while monitoring continued based on the set value, which may indicate a malfunction in the monitoring means. It also becomes possible to detect such a possibility.

[0039] (Discharge unit 300) Figure 8 is a block diagram of the monitoring system of the discharge unit 300 according to the first embodiment. The differences from Figure 7 will be mainly explained. When the signal potential of the power control signal 603 transitions from 0V to 3.3V, the power supply unit 410 outputs the discharge element drive voltage 901 to the main unit output terminal 451. The CPU 400 receives the input of the print signal 601 from the host device 500 and outputs the discharge element control signal 904 to the main unit output terminal 451. The main unit output terminal 451 outputs the discharge element drive voltage 901 and the discharge element control signal 904. In this embodiment, the discharge element drive voltage 901 is 28V. The discharge element drive voltage 901 and the discharge element control signal 904 output from the main unit output terminal 451 are transmitted to the liquid discharge head 1 via the head input terminal 452. The discharge element drive voltage 901 and the discharge element control signal 904 are transmitted to the discharge element drive signal output terminal 914 via the electrical wiring board 330. The ejection element drive signal output terminal 914 transmits the ejection element drive voltage 901 and the ejection element control signal 904 to the ejection element board 310 via the ejection element drive signal input terminal 915. The ejection element board 310 generates an ejection element drive signal 911 based on the ejection element drive voltage 901 and the ejection element control signal 904. The ejection element board 310 drives the ejection element based on the ejection element drive signal 911 to perform the ejection operation.

[0040] A monitoring unit 903 is provided between the head input terminal 452 and the ejection element drive signal output terminal 914. The head input terminal 452 and the monitoring unit 903 are provided on the head board 210. The head board 210 and the ejection element board 310 are electrically connected via an electrical wiring board 330. Therefore, the head input terminal 452 and the monitoring unit 903 are electrically connected to the ejection element drive signal output terminal 914 via the electrical wiring board 330. The ejection element drive signal output terminal 914 and the ejection element drive signal input terminal 915 are electrically connected by wire bonding or the like.

[0041] The monitoring unit 903 monitors the ejection element control signal supplied to the ejection element substrate 310 as a signal, and monitors the ejection element drive voltage supplied to the ejection element substrate 310 as a drive voltage. Specifically, the monitoring unit 903 receives the ejection element control signal 904 and diagnoses whether the ejection element control signal 904, which instructs the printing operation, is an abnormal signal or whether it may damage the ejection element substrate 310. If it diagnoses that there is no abnormality, the monitoring unit 903 permits the transmission of the ejection element control signal 904 to the ejection element substrate 310. The monitoring unit 903 also monitors the ejection element drive voltage 901 as a test voltage 902. Specifically, the monitoring unit 903 monitors whether the test voltage 902 is within a predetermined voltage range. If the monitoring unit 903 diagnoses that the ejection element control signal 904 or the ejection element drive voltage 901 is abnormal, it sends an error communication signal 905 to the CPU 400. When the CPU 400 receives an error communication signal 905, it stops transmitting the discharge element control signal 904 and the discharge element drive voltage 901. This action prevents damage to the discharge element board 310. In addition, to indicate whether the monitoring unit 903 itself is performing its monitoring operation normally, the monitoring unit 903 continuously transmits an operation confirmation signal 906 to the CPU 400. If an abnormality such as a malfunction occurs in the monitoring unit 903, the operation confirmation signal 906 will not be transmitted to the CPU 400. Therefore, if the CPU 400 cannot confirm the output of the operation confirmation signal 906 while monitoring based on the set value continues, it may diagnose that there is an abnormality in the liquid discharge head 1 and stop driving the liquid discharge head 1.

[0042] (Voltage divider circuit 910) Figure 9 is a block diagram showing that the monitoring system of the discharge unit 300 according to the first embodiment includes a voltage divider circuit. In Figure 8, an example was described in which the monitoring unit 903 monitors whether or not the discharge element drive voltage 901 is within a predetermined voltage range. In Figure 9, an example is described in which the monitoring unit 903 monitors the divided voltages obtained by further providing a voltage divider circuit 910, thereby dividing the discharge element drive voltage 901.

[0043] For example, if the test voltage 902 is a high voltage, the device on which the monitoring unit 903 is mounted must be a device with a voltage rating that can withstand the test voltage 902. In this case, the size or cost may increase. Furthermore, the degree of freedom in device selection may decrease. Therefore, instead of inputting the discharge element drive voltage 901 directly to the monitoring unit 903 as the test voltage 902, as shown in Figure 8, the test voltage 902 may be input to the monitoring unit 903 via a voltage divider circuit 910, as shown in Figure 9. That is, the discharge element drive voltage 901 may be reduced in voltage via the voltage divider circuit 910, and the divided voltage may be input to the monitoring unit 903 as the test voltage 902, thereby allowing the monitoring unit 903 to monitor the discharge element drive voltage 901.

[0044] According to the above description, the system may further include a voltage divider circuit 910 that supplies divided voltages obtained by dividing the drive voltage to a monitoring means. The monitoring means may set a set value to a voltage divider setting value corresponding to the divided voltage and monitor whether the divided voltage exceeds the set value. With this configuration, abnormalities occurring in the transmission path can be monitored with high sensitivity. Furthermore, damage to the ejection element substrate 310 can be prevented.

[0045] (Second embodiment) Figure 10 is a block diagram showing the monitoring system of the discharge unit 300 according to the second embodiment, which includes a main signal generation circuit and a peak hold circuit. The second embodiment differs from the first embodiment in that the main signal generation circuit 918, located outside the liquid discharge head 1 and in the recording device body, generates the discharge element drive signal 911, and the peak hold circuit 909 inside the liquid discharge head 1 extracts the peak voltage of the discharge element drive signal 911. The differences from the first embodiment will be mainly described below.

[0046] The recording device includes a main signal generation circuit 918. The main signal generation circuit 918 is supplied with an ejection element control signal 904 from the CPU 400. The main signal generation circuit 918 is supplied with an ejection element drive voltage 901 from the power supply unit 410. Based on the ejection element control signal 904 and the ejection element drive voltage 901, the main signal generation circuit 918 generates an ejection element drive signal 911. The potential of the ejection element drive signal 911 is high voltage and includes a digital signal. The ejection element drive signal 911 drives the ejection element on the ejection element substrate 310. The main signal generation circuit 918 outputs the ejection element drive signal 911 to the liquid ejection head 1 via the main output terminal 451. The liquid ejection head 1 supplies the ejection element drive signal 911 to the peak hold circuit 909, the monitoring unit 903, and the ejection element drive signal output terminal 914 via the head input terminal 452. The ejection element drive signal output terminal 914 supplies the ejection element drive signal 911 to the ejection unit 300. The ejection unit 300 supplies the ejection element drive signal 911 to the ejection element substrate 310 via the ejection element drive signal input terminal 915. The ejection element substrate 310 performs ink ejection operation according to the ejection element drive signal 911.

[0047] (Monitoring Department 903) The monitoring unit 903 receives the ejection element drive signal 911 as a test pulse 908 via a first transmission path branched from the transmission path to the ejection element drive signal output terminal 914. The monitoring unit 903 diagnoses whether the test pulse 908 is a logically abnormal signal. The peak hold circuit 909 also receives the ejection element drive signal 911 via a second transmission path branched from the first transmission path. The ejection element drive signal 911 includes a digital signal. The peak hold circuit 909 extracts the peak voltage of the ejection element drive signal 911. The peak hold circuit 909 generates a test voltage 902 based on the extracted peak voltage. The peak hold circuit 909 supplies the test voltage 902 to the monitoring unit 903. The monitoring unit 903 diagnoses whether the test voltage 902 is within a predetermined voltage range. That is, the monitoring unit 903 may set the set value to a peak set value corresponding to the test voltage 902 and monitor whether the test voltage 902 exceeds the set value. If the monitoring unit 903 diagnoses that at least one of the test pulse 908 and the test voltage 902 is abnormal, it sends an error communication signal 905 to the CPU 400. When the CPU 400 receives the error communication signal 905, it stops the printing operation. In addition, to indicate that the monitoring unit 903 is functioning normally, an operation confirmation signal 906 is sent to the CPU 400. Due to this operation, if there is an abnormality in the monitoring unit 903, the operation confirmation signal 906 is not sent to the CPU 400. Therefore, if the operation confirmation signal 906 is not received for a certain period of time, the CPU 400 may detect that there is an abnormality in the monitoring unit 903.

[0048] (Voltage divider circuit 910) Figure 11 is a block diagram of the monitoring system of the discharge element unit according to the second embodiment, which includes a main signal generation circuit 918, a voltage divider circuit 910, and a peak hold circuit 909. The voltage divider circuit 910 outputs a voltage-divided drive signal obtained by dividing the voltage of the drive signal. For example, the voltage divider circuit 910 in Figure 11 outputs a voltage-divided drive signal obtained by dividing the voltage of the discharge element drive signal 911 to the peak hold circuit 909. The monitoring unit 903 sets a set value to a voltage-divided peak set value corresponding to the test voltage 902 and monitors whether the test voltage 902 exceeds the set value. With this operation, the monitoring unit 903 can be supplied with a signal in which the voltage of the discharge element drive signal 911 has been reduced in potential via the voltage divider circuit 910. This makes it possible to suppress the increase in size or cost required to accommodate higher voltage resistance of the monitoring unit 903.

[0049] (Third embodiment) Figure 12 is a block diagram showing the monitoring system of the ink circulation unit according to the third embodiment, which includes a main unit signal generation circuit and a peak hold circuit. The third embodiment differs from the first embodiment in that the main unit signal generation circuit 918, located outside the liquid ejection head 1 and in the recording device body, generates the pump drive signal 913, and the peak hold circuit 909 inside the liquid ejection head 1 extracts the peak voltage of the pump drive signal 913. The third embodiment also differs from the second embodiment in that it drives the ink circulation unit 54 instead of the ejection unit 300. The differences from the first and second embodiments will be mainly described below.

[0050] The recording device includes a main signal generation circuit 918. The main signal generation circuit 918 is supplied with a head control signal 649 from the CPU 400. The main signal generation circuit 918 is supplied with a pump drive voltage 912 from the power supply unit 410. Based on the head control signal 649 and the pump drive voltage 912, the main signal generation circuit 918 generates a pump drive signal 913. The potential of the pump drive signal 913 is high and includes a digital signal. The pump drive signal 913 drives the circulation pump 27. The main signal generation circuit 918 outputs the pump drive signal 913 to the liquid discharge head 1 via the main output terminal 451. The liquid discharge head 1 supplies the pump drive signal 913 to the peak hold circuit 909, the monitoring unit 903, and the pump output terminal 455 via the head input terminal 452. The pump output terminal 455 supplies the pump drive signal 913 to the ink circulation unit 54. The ink circulation unit 54 supplies a pump drive signal 913 to the circulation pump 27 via the pump input terminal 456. The circulation pump 27 circulates the ink according to the pump drive signal 913.

[0051] (Monitoring Department 903) The monitoring unit 903 receives the pump drive signal 913 as a test pulse 908 via a first transmission line branched from the transmission line to the pump output terminal 455. The monitoring unit 903 diagnoses whether the test pulse 908 is a logically abnormal signal. The peak hold circuit 909 also receives the pump drive signal 913 via a second transmission line branched from the first transmission line. The pump drive signal 913 includes a digital signal. The peak hold circuit 909 extracts the peak voltage of the pump drive signal 913. The peak hold circuit 909 generates a test voltage 902 based on the extracted peak voltage. The peak hold circuit 909 supplies the test voltage 902 to the monitoring unit 903. The monitoring unit 903 diagnoses whether the test voltage 902 is within a predetermined voltage range. That is, the monitoring unit 903 may set a set value to a pump set value corresponding to the test voltage 902 and monitor whether the test voltage 902 exceeds the set value. If the monitoring unit 903 diagnoses that at least one of the test pulse 908 and the test voltage 902 is abnormal, it sends an error communication signal 905 to the CPU 400. When the CPU 400 receives the error communication signal 905, it stops the printing operation. In addition, to indicate that the monitoring unit 903 is functioning normally, it sends an operation confirmation signal 906 to the CPU 400. Through this operation, if there is an abnormality in the monitoring unit 903, the CPU 400 can detect that there is an abnormality in the monitoring unit 903.

[0052] (Voltage divider circuit 910) Figure 13 is a block diagram of the monitoring system of an ink circulation unit according to a third embodiment, which includes a main signal generation circuit, a voltage divider circuit, and a peak hold circuit. The voltage divider circuit 910 outputs a voltage-divided drive signal obtained by dividing the potential of the pump drive signal 913. For example, the voltage divider circuit 910 in Figure 13 outputs a voltage-divided pump drive signal obtained by dividing the voltage of the pump drive signal 913 to the peak hold circuit 909. The monitoring unit 903 sets a set value to a voltage-divided pump set value corresponding to the test voltage 902 and monitors whether the test voltage 902 exceeds the set value. With this operation, the monitoring unit 903 can be supplied with a signal in which the voltage of the pump drive signal 913 has been reduced in potential via the voltage divider circuit 910. This makes it possible to suppress the increase in size or cost required to accommodate higher voltage resistance of the monitoring unit 903.

[0053] (Fourth embodiment) Figure 14 is a block diagram showing that the monitoring system of the discharge unit 300 according to the fourth embodiment includes a circuit control unit 457 and a boost circuit 917. The fourth embodiment differs from the first to third embodiments in that the circuit control unit 457 and the boost circuit A917 are provided in the liquid discharge head 1 as a discharge element drive circuit. The differences from the first to third embodiments will be mainly described below.

[0054] The liquid discharge head 1 includes a discharge element drive circuit. That is, in this embodiment, a discharge element control signal 904 and a discharge element drive voltage 901 are generated within the liquid discharge head 1. The discharge element drive circuit includes a circuit control unit 457 and a boost circuit A917. The circuit control unit 457 and the boost circuit A917 are provided on the head board 210. That is, the head board 210 is provided with a monitoring unit 903, a circuit control unit 457, and a boost circuit A917. Therefore, the monitoring unit 903, the circuit control unit 457, and the boost circuit A917 are electrically connected within the same wiring system. Consequently, if the head board 210 is electrically affected by the surrounding environment, the same offset may be applied to the wiring network of the head board 210.

[0055] (Circuit control unit 457; monitoring unit 903) The circuit control unit 457 receives a reference voltage 644 supplied from the power supply unit 410 and starts operation. In this embodiment, a reference voltage of 5V is used for the reference voltage 644. The circuit control unit 457 receives a head control signal 649 supplied from the CPU 400. A logic circuit is provided inside the circuit control unit 457. Based on the head control signal 649, this logic circuit outputs an ejection element control signal 904 and a boost signal 626 to the monitoring unit 903. The monitoring unit 903 monitors whether there is an abnormality in the ejection element control signal 904 and the boost signal 626. If the monitoring unit 903 diagnoses that there is no abnormality in the ejection element control signal 904, it transmits the ejection element control signal 904 to the ejection element board 310 via the ejection element drive signal output terminal 914. On the other hand, if the monitoring unit 903 diagnoses that there is no abnormality in the boost signal 626, it transmits the boost signal 626 to the boost circuit A917.

[0056] (Boost circuit A917) The boost circuit A917, in accordance with the boost signal 625, boosts the reference voltage 644 to the discharge element drive voltage 901, which is the voltage required to drive the discharge element. In this embodiment, the discharge element drive voltage 901 is 28V. That is, the boost circuit A917 boosts the 5V reference voltage to the 28V discharge element drive voltage 901. The discharge element drive voltage 901 is supplied to the discharge element board 310 via the discharge element drive signal output terminal 914. With the discharge element drive voltage 901 supplied, the discharge element board 310 performs liquid discharge operation based on the discharge element control signal 904. The boost circuit A917 also supplies the discharge element drive voltage 901 as a test voltage 902 to the monitoring unit 903 via a branch line that branches off from the transmission line that transmits the discharge element drive voltage 901 to the discharge element drive signal output terminal 914. The monitoring unit 903 diagnoses whether the test voltage 902 is within a predetermined voltage range. If the monitoring unit 903 diagnoses that the test voltage 902 is not within the predetermined voltage range, it diagnoses that the test voltage 902 is abnormal and outputs an error communication signal 905 to the CPU 400. Upon receiving the error notification signal, the CPU 400 safely stops the operation of the discharge unit 300. In addition, to indicate that the monitoring unit 903 is functioning normally, an operation confirmation signal 906 is sent to the CPU 400. Due to this operation, if there is a problem with the monitoring unit 903, the operation confirmation signal 906 will not be sent to the CPU 400. Therefore, if the operation confirmation signal 906 is not received for a certain period of time, the CPU 400 may detect that there is a problem with the monitoring unit 903.

[0057] In this embodiment, an FPGA may also be used for the circuit control unit 457, similar to the monitoring unit 903. However, unlike the monitoring unit 903, the circuit control unit 457 changes its internal logic circuit settings based on the head control signal 649 and outputs the ejection element control signal 904 and the boost signal 626. Therefore, in the case of the circuit control unit 457, the setting values ​​written to its internal registers must be rewritable logic circuit devices. On the other hand, in the monitoring unit 903 of Figure 14, as explained using Figure 7, it is desirable that the setting values ​​of the registers are locked so that they cannot be rewritten.

[0058] From the above description, the recording device further includes a boost circuit A917. The boost circuit A917 outputs a discharge element drive voltage 901 obtained by boosting the reference voltage 644. The discharge unit 300 includes a discharge element substrate 310 that discharges liquid based on the discharge element drive voltage 901. The monitoring unit 903 may set a set value to a boost set value corresponding to the discharge element drive voltage 901 and monitor whether the discharge element drive voltage 901 exceeds the set value. With this configuration, it is possible to handle high voltage on the liquid discharge head 1 side without handling high voltage on the recording device body side. This makes it possible to protect the electronic circuits around the liquid discharge head 1 from high voltage.

[0059] (Voltage divider circuit 910) Figure 15 is a block diagram of the monitoring system of the discharge unit 300 according to the fourth embodiment, which includes a circuit control unit, a boost circuit, and a voltage divider circuit. In Figure 14, an example was described in which the monitoring unit 903 monitors whether the discharge element drive voltage 901 is within a predetermined voltage range. In Figure 15, an example is described in which the monitoring unit 903 monitors the divided voltage obtained by further providing a voltage divider circuit 910 from the discharge element drive voltage 901.

[0060] For example, if the test voltage 902 is a high voltage, the device on which the monitoring unit 903 is mounted must be a device with a voltage rating that can withstand the test voltage 902. In this case, the size or cost may increase. Furthermore, the degree of freedom in device selection may decrease. Therefore, instead of inputting the discharge element drive voltage 901 directly to the monitoring unit 903 as the test voltage 902, as shown in Figure 14, the test voltage 902 may be input to the monitoring unit 903 via a voltage divider circuit 910, as shown in Figure 15. That is, the discharge element drive voltage 901 may be reduced in voltage via the voltage divider circuit 910, and the divided voltage may be input to the monitoring unit 903 as the test voltage 902, thereby allowing the monitoring unit 903 to monitor the discharge element drive voltage 901.

[0061] According to the above description, the system may further include a voltage divider circuit 910 that supplies divided voltages, obtained by dividing the discharge element drive voltage, to a monitoring means. The monitoring means may set a set value to a voltage divider setting value corresponding to the divided voltage and monitor whether the divided voltage exceeds the set value. With this configuration, abnormalities occurring in the transmission path can be monitored with high sensitivity. Furthermore, damage to the discharge element substrate 310 can be prevented.

[0062] (Fifth embodiment) Figure 16 is a block diagram of the monitoring system of the ink circulation unit 54 according to the fifth embodiment, which includes a head information storage unit 458, a circuit control unit 457, a boost circuit B453, and an output switching circuit 454. The fifth embodiment differs from the first to third embodiments in that the circuit control unit 457, the boost circuit B453, and the output switching circuit 454 are provided as a pump drive circuit in the liquid discharge head 1. The fifth embodiment also differs from the fourth embodiment in that it controls the drive of the ink circulation unit 54. The differences from the first to fourth embodiments will be mainly described below.

[0063] The liquid discharge head 1 includes a pump drive circuit. That is, in this embodiment, unlike the third embodiment in which the pump drive signal 913 is generated outside the liquid discharge head 1, the pump drive signal 913 is generated inside the liquid discharge head 1. The pump drive circuit includes a circuit control unit 457, a boost circuit B453, and an output switching circuit 454. The liquid discharge head 1 also includes a head information storage unit 458. The head information storage unit 458 stores the head control signal 649. The circuit control unit 457, the boost circuit B453, and the output switching circuit 454 are provided on the head board 210. That is, the head board 210 is provided with a monitoring unit 903, a circuit control unit 457, a boost circuit B453, and an output switching circuit 454. Therefore, the monitoring unit 903, the circuit control unit 457, the boost circuit B453, and the output switching circuit 454 are electrically connected within the same wiring system. Therefore, if the head board 210 is electrically affected by the surrounding environment, the same offset may be applied to the wiring network of the head board 210.

[0064] (Circuit control unit 457; monitoring unit 903) The circuit control unit 457 receives a reference voltage 644 supplied from the power supply unit 410 and starts operation. In this embodiment, a reference voltage 644 of 5V is used. The circuit control unit 457 receives a head control signal 649 supplied from the CPU 400. A logic circuit is provided inside the circuit control unit 457. Based on the head control signal 649, this logic circuit outputs a pump control signal 645 to the output switching circuit 454 and outputs a boost signal 626 to the monitoring unit 903. If the monitoring unit 903 diagnoses that there is no abnormality in the boost signal 626, it transmits the boost signal 626 to the boost circuit B453.

[0065] (Boost circuit B453) The boost circuit B453, in accordance with the boost signal 626, boosts the reference voltage 644 to the pump drive voltage 647, which is the voltage required to drive the circulation pump 27. In this embodiment, the pump drive voltage 647 is 66V. That is, the boost circuit B453 boosts the 5V reference voltage 644 to the 66V pump drive voltage 647. The boost circuit B453 also supplies the pump drive voltage 647 to the monitoring unit 903 via a branch line that branches off from the transmission line that transmits the pump drive voltage 647 to the output switching circuit 454. The monitoring unit 903 diagnoses whether the pump drive voltage 647 is within a predetermined voltage range. If the monitoring unit 903 diagnoses that the pump drive voltage 647 is not within the predetermined voltage range, it diagnoses that the pump drive voltage 647 is abnormal and outputs an error communication signal 905 to the CPU 400. When the CPU 400 receives an error notification signal, it safely stops the operation of the circulation pump 27. In addition, an operation confirmation signal 906 is sent to the CPU 400 to indicate that the monitoring unit 903 is functioning normally. Due to this operation, if there is a problem with the monitoring unit 903, the operation confirmation signal 906 will not be sent to the CPU 400. Therefore, if the operation confirmation signal 906 is not received for a certain period of time, the CPU 400 may detect that there is a problem with the monitoring unit 903.

[0066] (Output switching circuit 454) The output switching circuit 454 generates a pump drive signal 913 based on the pump control signal 645 when the pump drive voltage 647 is supplied. Specifically, the pump control signal 645 includes a first signal corresponding to the first electrode 272 and a second signal corresponding to the second electrode 274. The pump control signal 645 is highly active. The pump control signal 645 becomes active when its voltage transitions from 0V to 3.3V. When the pump control signal 645 becomes active, the output switching circuit 454 outputs the pump drive signal 913 to the ink circulation unit 54 via the pump output terminal 455. The pump drive signal 913 includes either the first pump drive signal corresponding to the first electrode 272 or the second pump drive signal corresponding to the second electrode 274. For example, if the first signal becomes active, the first pump drive signal is blocked, and if the second signal becomes active, the second pump drive signal is blocked. The first and second signals alternately transition to active during the drive cycle. This creates alternating potential differences in opposite directions between the first electrode 272 and the second electrode 274 during the drive cycle, driving the circulation pump 27. In other words, the ink circulation unit 54 drives the circulation pump by transmitting the pump drive signal 913 to the circulation pump 27 via the pump input terminal 456, thereby circulating the ink.

[0067] In this embodiment, similar to the fourth embodiment, the circuit control unit 457 uses an FPGA, and the setting values ​​written to its internal registers must be rewritable logic circuit devices. On the other hand, as explained with reference to Figure 7, it is desirable that the monitoring unit 903 in Figure 16 has its register setting values ​​locked so that they cannot be rewritten.

[0068] From the above description, the recording device further comprises a boost circuit B453 and an output switching circuit 454. The boost circuit B453 outputs a pump drive voltage 647 obtained by boosting the reference voltage 644. The output switching circuit 454, while the pump drive voltage is supplied, alternately outputs a first pump drive signal and a second pump drive signal in the drive cycle. The circulation pump 27 circulates the liquid according to the drive cycle based on the first pump drive signal and the second pump drive signal. The monitoring unit 903 sets a boost setting value corresponding to the pump drive voltage and monitors whether the pump drive voltage exceeds the setting value. With this configuration, it is possible to handle high voltage on the liquid discharge head 1 side without handling high voltage on the recording device main body side. This makes it possible to protect the electronic circuits around the liquid discharge head 1 from high voltage.

[0069] (Voltage divider circuit 910) Figure 17 is a block diagram of the monitoring system of the ink circulation unit 54 according to the fifth embodiment, which includes a head information storage unit 458, a circuit control unit 457, a boost circuit B453, a voltage divider circuit 910, and an output switching circuit 454. In Figure 16, an example was described in which the monitoring unit 903 monitors whether the pump drive voltage 647 is within a predetermined voltage range. In Figure 17, an example is described in which the monitoring unit 903 monitors the divided voltage obtained by dividing the pump drive voltage 647 as a test voltage 902 by further providing the voltage divider circuit 910.

[0070] For example, if the test voltage 902 is a high voltage, the device on which the monitoring unit 903 is mounted must be a device with a voltage rating that can withstand the test voltage 902. In this case, the size or cost may increase. Furthermore, the degree of freedom in selecting the device may decrease. Therefore, instead of inputting the pump drive voltage 647 directly to the monitoring unit 903 as the test voltage 902, as shown in Figure 16, the test voltage 902 may be input to the monitoring unit 903 via the voltage divider circuit 910, as shown in Figure 17. That is, the pump drive voltage 647 may be reduced in voltage via the voltage divider circuit 910, and the divided voltage may be input to the monitoring unit 903 as the test voltage 902, thereby allowing the monitoring unit 903 to monitor the pump drive voltage 647.

[0071] According to the above description, the system may further include a voltage divider circuit 910 that supplies divided voltages, obtained by dividing the pump drive voltage, to a monitoring means. The monitoring means may set a set value to a voltage divider setting value corresponding to the divided voltage and monitor whether the divided voltage exceeds the set value. With this configuration, abnormalities occurring in the transmission path can be monitored with high sensitivity. Furthermore, damage to the circulation pump 27 can be prevented.

[0072] (Sixth embodiment) Figure 18 is a block diagram of the monitoring system of the discharge unit according to the sixth embodiment, which includes a circuit control unit 457, a boost circuit B917, and a voltage divider circuit 910b. Also, Figure 18 is a block diagram of the monitoring system of the ink circulation unit 54, which includes a circuit control unit 457, a boost circuit A453, a voltage divider circuit 910a, and an output switching circuit 454. The sixth embodiment differs from the first to fifth embodiments in that it is a combination of the fourth and fifth embodiments. The differences from the first to fifth embodiments will be mainly described below.

[0073] The monitoring unit 903 monitors whether the voltage of the boost signal 626a to be transmitted to the boost circuit A453 is within a predetermined voltage range. If the voltage of the boost signal 626a to be transmitted to the boost circuit A453 is not within the predetermined voltage range, the monitoring unit 903 transmits an error communication signal 905 to the CPU 400. On the other hand, the monitoring unit 903 also monitors whether the voltage of the boost signal 626b to be transmitted to the boost circuit B917 is within a predetermined voltage range. If the voltage of the boost signal 626b to be transmitted to the boost circuit B917 is not within the predetermined voltage range, the monitoring unit 903 transmits an error communication signal 905 to the CPU 400.

[0074] The monitoring unit 903 monitors the pump drive voltage 647 supplied as the voltage source for the pump drive signal 913 supplied to the circulation pump 27. On the other hand, the monitoring unit 903 also monitors the discharge element control signal 904 supplied to the discharge element substrate 310 and the discharge element drive voltage 901 supplied to the discharge element substrate 310. In this embodiment as well, if the CPU 400 cannot confirm the output of the operation confirmation signal, it stops at least one of the drive for circulating the liquid and the drive for discharging the liquid. Thus, the configuration including the monitoring unit 903 inside the liquid discharge head 1 is applicable to the liquid discharge head 1 that performs various signal transmission and signal generation. Furthermore, by including the monitoring unit 903 inside the liquid discharge head 1, it is possible to accurately detect abnormalities inside the liquid discharge head 1.

[0075] <Other Embodiments> Although various examples and embodiments of this disclosure have been described above, the spirit and scope of this disclosure are not limited to the specific descriptions herein. This disclosure is not limited to the embodiments described above, and various modifications may be made. Furthermore, this disclosure may combine some of the embodiments described above as appropriate.

[0076] (Variation 1) For example, we have described one example of a storage device operating in a high-active state, but it is not limited to this. For example, a storage device may operate in a low-active state.

[0077] (Modification 2) An example has been described in which the setting values ​​used by the monitoring unit 903 for monitoring are set to be unrewritable, but this is not the only example. Specifically, as shown in Figures 14, 15, or 16, 17, when the circuit control unit 457 is located inside the liquid discharge head 1, both the circuit control unit 457 and the monitoring unit 903 are located on the head board 210 inside the liquid discharge head 1. Therefore, as explained in Figures 14 and 16 respectively, if the circuit control unit 457 and the monitoring unit 903 are electrically affected by changes in the surrounding environment, the same offset may be applied to the wiring network of the head board 210. That is, since the drive voltage or control signal is monitored within the same wiring system, the setting values ​​used by the monitoring unit 903 for monitoring do not need to be set to be unrewritable. However, if the monitoring unit 903 diagnoses an abnormality as a result of its monitoring, it may transmit an error communication signal 905 to the CPU 400, and the CPU 400 may stop the operation of the liquid discharge head 1. Furthermore, if the monitoring unit 903 detects an abnormality, the operation may be stopped by controlling the supply of various drive voltages or control signals to the boost circuit A453, etc.

[0078] In other words, the liquid discharge head 1 comprises a driving means and a monitoring means. The driving means can perform at least one of the following: a drive to circulate the liquid and a drive to discharge the liquid based on a printing signal. The monitoring means sets at least one of the two drives, the liquid circulation drive and the liquid circulation drive, as the target for monitoring, and monitors at least one of the signal supplied to the target and the drive voltage supplied to the target based on a predetermined set value. Furthermore, if the drive voltage exceeds the range defined by the set value, the monitoring means may stop supplying at least one of the signal and the drive voltage to the target for monitoring. With this configuration, even if the liquid discharge head is not able to operate normally, the supply of at least one of the signal and the drive voltage that serve as the driving source for operation is stopped, so the operation of the liquid discharge head can be reliably stopped. That is, even if an electrical abnormality occurs, it can be safely stopped.

[0079] The disclosure of this embodiment includes configurations represented by the following liquid dispensing head and recording device.

[0080] <Configuration 1> A drive means capable of performing at least one of the following: a drive to circulate the liquid and a drive to discharge the liquid based on a printing signal, A monitoring means that sets at least one of the drives that circulate the liquid and the drives that discharge the liquid as the target for monitoring, and monitors at least one of the signal supplied to the target for monitoring and the drive voltage supplied to the target for monitoring based on a predetermined set value, Equipped with, The liquid dispensing head is characterized in that the aforementioned setting value is set to be unrewritable.

[0081] <Configuration 2> A drive means capable of performing at least one of the following: a drive to circulate the liquid and a drive to discharge the liquid based on a printing signal, A monitoring means that sets at least one of the drives for circulating the liquid and the drives for discharging the liquid as the target for monitoring, and monitors at least one of the signal supplied to the target for monitoring and the drive voltage supplied to the target for monitoring based on a predetermined set value, Equipped with, The liquid dispensing head is characterized in that the monitoring means stops supplying at least one of the signal and the drive voltage to the monitored object when the drive voltage exceeds the range defined by the set value.

[0082] <Structure 3> The liquid discharge head according to configuration 2, characterized in that the aforementioned setting value is set to be unrewritable.

[0083] <Structure 4> The liquid discharge head according to configuration 1, characterized in that the monitoring means stops supplying at least one of the signal and the driving voltage to the monitored object when the driving voltage exceeds the range defined by the set value.

[0084] <Composition 5> The liquid dispensing head according to configuration 1, characterized in that the monitoring means outputs an operation confirmation signal to the outside indicating that monitoring has been performed while monitoring continues based on the set value.

[0085] <Composition 6> The liquid discharge head according to configuration 1, characterized in that the monitoring means transmits an error notification signal to the outside when the drive voltage exceeds the range defined by the set value.

[0086] <Composition 7> The liquid dispensing head according to configuration 2, characterized in that the monitoring means outputs an operation confirmation signal to the outside indicating that monitoring has been performed while monitoring continues based on the set value.

[0087] <Structure 8> The liquid discharge head according to configuration 2, characterized in that the monitoring means transmits an error notification signal to the outside when the drive voltage exceeds the range defined by the set value.

[0088] <Composition 9> The driving means includes a discharge element substrate for discharging the liquid, The liquid discharge head according to configuration 1, characterized in that the monitoring means monitors the discharge element control signal supplied to the discharge element substrate as the signal, and monitors the discharge element drive voltage supplied to the discharge element substrate as the drive voltage.

[0089] <Composition 10> The system further comprises a voltage divider circuit that supplies the divided voltage obtained by dividing the drive voltage to the monitoring means, The liquid discharge head according to configuration 9, characterized in that the monitoring means sets the set value to a divided voltage set value corresponding to the divided voltage, and monitors whether or not the divided voltage exceeds the set value.

[0090] <Composition 11> A signal generation circuit that outputs a drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A peak hold circuit supplies a test voltage generated based on the peak voltage of the drive signal to the monitoring means, Furthermore, The liquid discharge head according to configuration 9, characterized in that the monitoring means sets the set value to a peak set value corresponding to the test voltage and monitors whether or not the test voltage exceeds the set value.

[0091] <Composition 12> A signal generation circuit that outputs a drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A voltage divider circuit that outputs a voltage-divided drive signal obtained by dividing the voltage of the aforementioned drive signal, A peak hold circuit supplies a test voltage generated based on the peak voltage of the voltage divider drive signal to the monitoring means, Furthermore, The liquid discharge head according to configuration 9, characterized in that the monitoring means sets the set value to a partial voltage peak set value corresponding to the test voltage and monitors whether or not the test voltage exceeds the set value.

[0092] <Composition 13> A signal generation circuit that supplies a pump drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A peak hold circuit supplies a test voltage generated based on the peak voltage of the pump drive signal to the monitoring means, Furthermore, The drive means includes a circulating pump that circulates the liquid based on the pump drive signal, The liquid discharge head according to configuration 1, characterized in that the monitoring means sets the set value to a pump set value corresponding to the inspection voltage and monitors whether the inspection voltage exceeds the set value.

[0093] <Composition 14> A signal generation circuit that supplies a pump drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A voltage divider circuit outputs a voltage-divided pump drive signal obtained by dividing the voltage of the pump drive signal, A peak hold circuit supplies a test voltage generated based on the peak voltage of the voltage divider pump drive signal to the monitoring means, Furthermore, The drive means includes a circulating pump that circulates the liquid based on the pump drive signal, The liquid discharge head according to configuration 1, characterized in that the monitoring means sets the set value to a partial pressure pump set value corresponding to the inspection voltage and monitors whether the inspection voltage exceeds the set value.

[0094] <Composition 15> It further includes a boost circuit that outputs a boosted reference voltage for driving the discharge element, The driving means includes a discharge element substrate that discharges the liquid based on the discharge element driving voltage, The liquid discharge head according to configuration 1, characterized in that the monitoring means sets the set value to a boosted set value corresponding to the discharge element drive voltage, and monitors whether or not the discharge element drive voltage exceeds the set value.

[0095] <Composition 16> The system further comprises a voltage divider circuit that supplies a divided voltage, obtained by dividing the discharge element drive voltage, to the monitoring means. The liquid discharge head according to configuration 15, characterized in that the monitoring means sets the set value to a divided voltage set value corresponding to the divided voltage, and monitors whether or not the divided voltage exceeds the set value.

[0096] <Composition 17> A boost circuit that outputs a pump drive voltage obtained by boosting the reference voltage, With the aforementioned pump drive voltage supplied, an output switching circuit alternately outputs a first pump drive signal and a second pump drive signal in a drive cycle, Furthermore, The aforementioned driving means is The system includes a circulating pump that circulates the liquid according to the drive cycle based on the first pump drive signal and the second pump drive signal, The liquid discharge head according to configuration 1, characterized in that the monitoring means sets the set value to a boosted set value corresponding to the pump drive voltage and monitors whether or not the pump drive voltage exceeds the set value.

[0097] <Composition 18> The system further comprises a voltage divider circuit that supplies a divided voltage, obtained by dividing the pump drive voltage, to the monitoring means. The liquid discharge head according to configuration 17, characterized in that the monitoring means sets the set value to a divided voltage set value corresponding to the divided voltage, and monitors whether or not the divided voltage exceeds the set value.

[0098] <Composition 19> The aforementioned driving means is A dispensing element substrate for dispensing the aforementioned liquid, A circulation pump for circulating the aforementioned liquid, Equipped with, The monitoring means is The control signal supplied to the ejection element substrate is monitored as the signal, and the voltage supplied to the ejection element substrate is monitored as the drive voltage. The liquid discharge head according to configuration 1, characterized in that the pump drive voltage supplied as a voltage source for the pump drive signal supplied to the circulation pump is monitored as the drive voltage.

[0099] <Composition 20> A liquid dispensing head as described in any one of configurations 1 to 19, A carriage that moves the liquid discharge head in a scanning direction perpendicular to the transport direction of the medium to be discharged, A conveying means for conveying the discharged medium in the conveying direction, A control means that controls the liquid discharge head, the carriage and the transport means based on the print signal to discharge the liquid from the liquid discharge head into the medium to be discharged, A recording device equipped with the following features.

[0100] <Composition 21> The recording device according to configuration 20, characterized in that the control means stops at least one of the drive for circulating the liquid and the drive for discharging the liquid if, while the monitoring based on the set value is continued, the output of an operation confirmation signal indicating that the monitoring has been performed cannot be confirmed.

[0101] <Composition 22> The recording device according to configuration 20, characterized in that the control means stops at least one of the drive for circulating the liquid and the drive for discharging the liquid when it detects an error notification signal transmitted when the drive voltage exceeds the range defined by the set value. [Explanation of Symbols]

[0102] 1. Liquid dispensing head 54 Ink circulation unit 300 Discharge Unit 903 Monitoring Department

Claims

1. A drive means capable of performing at least one of the following: a drive to circulate the liquid and a drive to discharge the liquid based on a printing signal, A monitoring means that sets at least one of the drives for circulating the liquid and the drives for discharging the liquid as the target for monitoring, and monitors at least one of the signals supplied to the target for monitoring and the drive voltage supplied to the target for monitoring based on a predetermined set value, Equipped with, The liquid dispensing head is characterized in that the aforementioned setting value is set to be unrewritable.

2. A drive means capable of performing at least one of the following: a drive to circulate the liquid and a drive to discharge the liquid based on a printing signal, A monitoring means that sets at least one of the drives for circulating the liquid and the drives for discharging the liquid as the target for monitoring, and monitors at least one of the signal supplied to the target for monitoring and the drive voltage supplied to the target for monitoring based on a predetermined set value, Equipped with, The liquid dispensing head is characterized in that the monitoring means stops supplying at least one of the signal and the drive voltage to the monitored object when the drive voltage exceeds the range defined by the set value.

3. The liquid dispensing head according to claim 2, characterized in that the aforementioned setting value is set to be unrewritable.

4. The liquid discharge head according to claim 1, characterized in that the monitoring means stops supplying at least one of the signal and the driving voltage to the monitored object when the driving voltage exceeds the range defined by the set value.

5. The liquid dispensing head according to claim 1, characterized in that the monitoring means outputs an operation confirmation signal to the outside indicating that the monitoring has been performed while monitoring continues based on the set value.

6. The liquid dispensing head according to claim 1, characterized in that the monitoring means transmits an error notification signal to the outside when the drive voltage exceeds the range defined by the set value.

7. The liquid dispensing head according to claim 2, characterized in that the monitoring means outputs an operation confirmation signal to the outside indicating that monitoring has been performed while monitoring continues based on the set value.

8. The liquid discharge head according to claim 2, characterized in that the monitoring means transmits an error notification signal to the outside when the drive voltage exceeds the range defined by the set value.

9. The driving means includes a discharge element substrate for discharging the liquid, The liquid discharge head according to claim 1, characterized in that the monitoring means monitors the discharge element control signal supplied to the discharge element substrate as the signal, and monitors the discharge element drive voltage supplied to the discharge element substrate as the drive voltage.

10. The system further comprises a voltage divider circuit that supplies the divided voltage obtained by dividing the drive voltage to the monitoring means, The liquid discharge head according to claim 9, characterized in that the monitoring means sets the set value to a divided voltage set value corresponding to the divided voltage and monitors whether the divided voltage exceeds the set value.

11. A signal generation circuit that outputs a drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A peak hold circuit supplies a test voltage generated based on the peak voltage of the drive signal to the monitoring means, Furthermore, The liquid discharge head according to claim 9, characterized in that the monitoring means sets the set value to a peak set value corresponding to the test voltage and monitors whether the test voltage exceeds the set value.

12. A signal generation circuit that outputs a drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A voltage divider circuit that outputs a voltage-divided drive signal obtained by dividing the voltage of the aforementioned drive signal, A peak hold circuit supplies a test voltage generated based on the peak voltage of the voltage divider drive signal to the monitoring means, Furthermore, The liquid discharge head according to claim 9, characterized in that the monitoring means sets the set value to a partial voltage peak set value corresponding to the test voltage and monitors whether or not the test voltage exceeds the set value.

13. A signal generation circuit that supplies a pump drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A peak hold circuit supplies a test voltage generated based on the peak voltage of the pump drive signal to the monitoring means, Furthermore, The drive means includes a circulating pump that circulates the liquid based on the pump drive signal, The liquid discharge head according to claim 1, characterized in that the monitoring means sets the set value to a pump set value corresponding to the inspection voltage and monitors whether the inspection voltage exceeds the set value.

14. A signal generation circuit that supplies a pump drive signal generated based on the aforementioned signal and the aforementioned drive voltage, A voltage divider circuit outputs a voltage-divided pump drive signal obtained by dividing the voltage of the pump drive signal, A peak hold circuit supplies a test voltage generated based on the peak voltage of the voltage divider pump drive signal to the monitoring means, Furthermore, The drive means includes a circulating pump that circulates the liquid based on the pump drive signal, The liquid discharge head according to claim 1, characterized in that the monitoring means sets the set value to a partial pressure pump set value corresponding to the inspection voltage and monitors whether the inspection voltage exceeds the set value.

15. It further includes a boost circuit that outputs a boosted reference voltage for driving the discharge element, The driving means includes a discharge element substrate that discharges the liquid based on the discharge element driving voltage, The liquid discharge head according to claim 1, characterized in that the monitoring means sets the set value to a boosted set value corresponding to the discharge element drive voltage and monitors whether or not the discharge element drive voltage exceeds the set value.

16. The system further comprises a voltage divider circuit that supplies a divided voltage, obtained by dividing the discharge element drive voltage, to the monitoring means. The liquid discharge head according to claim 15, characterized in that the monitoring means sets the set value to a divided voltage set value corresponding to the divided voltage and monitors whether or not the divided voltage exceeds the set value.

17. A boost circuit that outputs a pump drive voltage obtained by boosting the reference voltage, With the aforementioned pump drive voltage supplied, an output switching circuit alternately outputs a first pump drive signal and a second pump drive signal in a drive cycle, Furthermore, The aforementioned driving means is The system includes a circulating pump that circulates the liquid according to the drive cycle based on the first pump drive signal and the second pump drive signal, The liquid discharge head according to claim 1, characterized in that the monitoring means sets the set value to a boosted set value corresponding to the pump drive voltage and monitors whether or not the pump drive voltage exceeds the set value.

18. The system further comprises a voltage divider circuit that supplies a divided voltage, obtained by dividing the pump drive voltage, to the monitoring means. The liquid discharge head according to claim 17, characterized in that the monitoring means sets the set value to a divided voltage set value corresponding to the divided voltage, and monitors whether or not the divided voltage exceeds the set value.

19. The aforementioned driving means is A dispensing element substrate for dispensing the aforementioned liquid, A circulation pump for circulating the aforementioned liquid, Equipped with, The aforementioned monitoring means is The control signal supplied to the ejection element substrate is monitored as the signal, and the voltage supplied to the ejection element substrate is monitored as the drive voltage. The liquid discharge head according to claim 1, characterized in that it monitors the pump drive voltage supplied as a voltage source for the pump drive signal supplied to the circulation pump as the drive voltage.

20. A liquid dispensing head according to any one of claims 1 to 19, A carriage that moves the liquid discharge head in a scanning direction perpendicular to the transport direction of the medium to be discharged, A conveying means for conveying the discharged medium in the conveying direction, A control means that controls the liquid discharge head, the carriage and the transport means based on the print signal to discharge the liquid from the liquid discharge head into the medium to be discharged, A recording device equipped with the following features.

21. The recording device according to claim 20, characterized in that the control means stops at least one of the drive for circulating the liquid and the drive for discharging the liquid if it is not possible to confirm the output of an operation confirmation signal indicating that the monitoring has been performed while the monitoring based on the set value is continued.

22. The recording device according to claim 20, characterized in that the control means stops at least one of the drive for circulating the liquid and the drive for discharging the liquid when it detects an error notification signal transmitted when the drive voltage exceeds the range defined by the set value.

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