Liquid discharge device and head unit

Abstract

To provide a liquid discharge device that can accurately detect a temperature of a print head.SOLUTION: The liquid discharge device is provided with a driving circuit that outputs a driving signal, a print head that receives the driving signal to discharge liquid, and a temperature information output circuit that obtains a head temperature signal corresponding to a temperature of the print head. The temperature information output circuit has a temperature information obtaining circuit that obtains temperature information corresponding to the temperature of the print head from the head temperature signal, and a timing control circuit that controls a timing at which the temperature information obtaining circuit obtains the temperature information. The timing control circuit determines whether a voltage value of the driving signal is constant or not and outputs a timing control signal for controlling the timing at which the temperature information obtaining circuit obtains the temperature information, on the basis of a determined result.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device and a head unit. [Background technology]

[0002] The liquid ejection device includes a printer having a piezoelectric element, a pressure chamber, and a nozzle communicating with the pressure chamber. The print head is driven by a piezoelectric element. By changing the volume of the pressure chamber, the liquid supplied to the pressure chamber is ejected from the nozzle. In a liquid ejection device equipped with such a print head, ink stored in the print head By controlling the drive of the piezoelectric element based on the temperature of the ink, ejection control suitable for the temperature of the ink is performed. Techniques for achieving this are known.

[0003] For example, Patent Document 1 discloses a method for detecting the temperature of a print head by a temperature detection unit provided inside the print head. The temperature of the print head is detected, and the piezoelectric element is driven based on the detected temperature of the print head. A technique for controlling the above is disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2024-051474 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 does not allow accurate detection of the temperature of the print head. There was room for improvement in terms of [Means for solving the problem]

[0006] One aspect of the liquid ejection device according to the present invention is a drive circuit that outputs a drive signal; a print head that receives the drive signal and ejects liquid; a temperature information output circuit for acquiring a head temperature signal corresponding to the temperature of the print head; Equipped with The temperature information output circuit temperature information that corresponds to the temperature of the print head from the head temperature signal; an information acquisition circuit; Timing control for controlling the timing at which the temperature information acquisition circuit acquires the temperature information The circuit and and The timing control circuit determines whether the voltage value of the drive signal is constant, and Based on the result, the timing at which the temperature information acquisition circuit acquires the temperature information is controlled. Outputs a timing control signal.

[0007] One aspect of the head unit according to the present invention is a print head that receives a drive signal and ejects liquid; a temperature information output circuit for acquiring a head temperature signal corresponding to the temperature of the print head; Equipped with The temperature information output circuit temperature information that corresponds to the temperature of the print head from the head temperature signal; an information acquisition circuit; Timing control for controlling the timing at which the temperature information acquisition circuit acquires the temperature information The circuit and and The timing control circuit determines whether the voltage value of the drive signal is constant, and Based on the result, the timing at which the temperature information acquisition circuit acquires the temperature information is controlled. Outputs a timing control signal. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a liquid ejection device. [Figure 2] FIG. 2 is an exploded perspective view showing the structure of a print head. [Figure 3] FIG. 1 is a plan view of the print head as viewed along the Z axis. [Figure 4] FIG. 4 is a cross-sectional view of the print head taken along the line Aa in FIG. 3. [Figure 5] FIG. 5 is a detailed view of the main part of FIG. 4 showing the details of the main part. [Figure 6] FIG. 4 is a cross-sectional view of the print head taken along the line Bb in FIG. 3. [Figure 7] FIG. 2 is a diagram illustrating a functional configuration of the liquid ejection device. [Figure 8] 10A and 10B are diagrams illustrating an example of a signal waveform of a drive signal COM. [Figure 9] FIG. 2 is a diagram illustrating a configuration of a drive signal selection circuit. [Figure 10] FIG. 10 is a diagram showing an example of the decoded content in the decoder. [Figure 11] FIG. 2 is a diagram illustrating a configuration of a selection circuit. [Figure 12] 10A and 10B are diagrams for explaining the operation of a drive signal selection circuit. [Figure 13] FIG. 2 is a diagram illustrating an example of the configuration of a temperature detection circuit. [Figure 14] FIG. 2 is a diagram illustrating an example of the configuration of a temperature information output circuit. [Figure 15] FIG. 2 is a diagram illustrating an example of a configuration of a comparison circuit and a timing control circuit. [Figure 16] 10A to 10C are diagrams illustrating an example of the operation of the liquid ejection device. [Figure 17] FIG. 10 is a diagram illustrating an example of the operation of the temperature information output circuit. [Figure 18] FIG. 10 is a diagram illustrating an example of the operation of the temperature information output circuit. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. The embodiments described below are for convenience only. The contents of the disclosure are not unduly limited. Furthermore, all of the configurations described below are included in the present invention. It is not necessarily a required component.

[0010] 1. Schematic configuration of the liquid ejection device FIG. 1 is a diagram showing a schematic configuration of a liquid ejection device 1. The liquid ejection device 1 of this embodiment includes: A carriage 21 mounted with a print head 22 that ejects ink as an example of liquid is moved. The ink ejection mechanism moves back and forth along the scanning axis and ejects ink onto the medium P being transported along the transport direction. In this way, a desired image is formed on the medium P by a so-called serial printing inkjet printer. The medium P in the liquid ejection device 1 may be a printing paper, a resin film, a fabric, etc. Any printing object can be used. The liquid ejection device 1 is a serial printing type. This is not limited to inkjet printers, but also applies to line printing inkjet printers. The liquid ejection device 1 is not limited to an inkjet printer. It is not a color material ejection device used in the manufacture of color filters for liquid crystal displays, etc., but an organic Electrode material used for forming electrodes in EL displays, FEDs (surface-emitting displays), etc. Discharge device, bioorganic substance discharge device used in biochip manufacturing, three-dimensional modeling device, and textile printing equipment It may be a position or the like.

[0011] In the following description, the three mutually orthogonal spatial axes, the X-axis, the Y-axis, and the Z-axis, are referred to as In the following description, the X-axis, the Y-axis, and the Z-axis are used. When specifying the direction of the arrow, the tip of the arrow indicating the direction along the X axis is the +X side, The starting point side is called the -X side, and the tip side of the arrow indicating the direction along the Y axis in the figure is the +Y side. is called the -Y side, the tip side of the arrow indicating the direction along the Z axis is the +Z side, and the starting point side is the -Z It is called the side.

[0012] As shown in FIG. 1, the liquid ejection device 1 includes a control unit 10, a head unit 20, a moving unit The printer includes a knit 30, a transport unit 40, and an ink container 90.

[0013] The ink container 90 stores a plurality of types of ink to be ejected onto the medium P. The ink container 90 in which such ink is stored may be an ink cartridge, a flexible filter, or the like. It uses a bag-shaped ink pack made of rubber and an ink tank that can be refilled with ink. It is possible.

[0014] The control unit 10 includes a CPU (Central Processing Unit) and an FPGA (Field Programmable Gate Array). The head unit includes a processing circuit such as a memory gate array (MGA) and a storage circuit such as a semiconductor memory. The controller 20 controls each element of the liquid ejection device 1 .

[0015] The head unit 20 includes a carriage 21 and a plurality of print heads 22. The edge 21 is fixed to an endless belt 32 included in a moving unit 30, which will be described later. The print heads 22 are mounted on a carriage 21. Each of the rods 22 receives a control signal Ctrl-H output from the control unit 10 and a drive signal Ctrl-H. A signal COM is input to each of the print heads 22. Ink stored in the container 90 is supplied via a tube or the like (not shown). The head 22 controls the ink container 20 based on the input control signal Ctrl-H and the drive signal COM. At this time, the print head 22 ejects ink. The direction along the Z axis from the -Z side to the +Z side along the Z axis is defined as the discharge direction. It may be referred to as.

[0016] The moving unit 30 includes a carriage motor 31 and an endless belt 32. The motor 31 operates based on the control signal Ctrl-C input from the control unit 10. The endless belt 32 extends along the X axis and moves in accordance with the operation of the carriage motor 31. This causes the carriage 21 fixed to the endless belt 32 to move along the X axis. That is, the moving unit 30 moves the plurality of print heads mounted on the carriage 21. The drive 22 is reciprocated along the X axis. When the direction along the X axis along which the multiple print heads 22 mounted on the printer move is referred to as the scanning direction, There is.

[0017] The transport unit 40 includes a transport motor 41 and a transport roller 42. 1 operates based on a control signal Ctrl-T input from the control unit 10. The rollers 42 rotate in accordance with the operation of the transport motor 41 while holding the medium P therebetween. As a result, the medium P sandwiched between the transport rollers 42 moves from the −Y side to the +Y side along the Y axis. That is, the transport unit 40 transports the medium P along the Y axis from the -Y side to the +Y side. In the following description, the medium P is conveyed from the -Y side to the +Y side. The direction toward the Y side may be referred to as the transport direction.

[0018] In the liquid ejection device 1 configured as above, the moving unit 30 controls the movement of the carriage 21. The transport unit 40 controls the reciprocating movement of the medium P along the transport direction. The carriage 21 is controlled to move back and forth along the scanning direction and the medium P In conjunction with the conveyance of the sheet in the conveying direction, the print head 22 mounted on the carriage 21 moves in the direction of the ink jet head. As a result, the ink ejected by the print head 22 is applied to any surface of the medium P. The ink droplets can be made to land on the medium P, forming a desired image on the medium P.

[0019] 2. Schematic structure of the print head Next, an example of the structure of the print head 22 of the head unit 20 will be described. FIG. 2 is an exploded perspective view showing the structure of the print head 22, and FIG. 22 along the Z axis, and FIG. 4 is a plan view of the Aa cross section shown in FIG. FIG. 5 is a detailed view of the main part of FIG. 4; 6 is a cross-sectional view of the print head 22 taken along the line Bb in FIG. 3, the peripheral configuration of the pressure chamber substrate 310 is mainly illustrated, and the protective substrate 330, the case member 340, etc. 4, the configuration of the piezoelectric element 60 is shown in a simplified manner.

[0020] As shown in FIG. 2, the print head 22 includes a pressure chamber substrate 310, a communication plate 315, a nozzle The plate 320, the compliance substrate 345, the protection substrate 330, the case member 340, and The piezoelectric element 60 includes a wiring substrate 420, a vibration plate 350, and a piezoelectric element 60, which will be described later.

[0021] The pressure chamber substrate 310 may be, for example, a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates. As shown in FIG. 3, the pressure chamber substrate 310 has a plurality of pressure chambers arranged along the Y axis. Two rows of pressure chambers, each with a row of chambers 312, are formed along the X axis. The pressure chambers 312 are arranged such that the positions of the pressure chambers 312 forming each pressure chamber row along the X axis are the same. The pressure chambers are arranged in a straight line along the Y axis. 6, the pressure chamber substrate 312 is partitioned by a partition wall 311. The arrangement of the pressure chambers 312 in the nozzle 10 is not limited to the above arrangement, and may be, for example, The pressure chambers 312 are arranged in rows such that the positions of the pressure chambers 312 along the X axis are different. In the following description, the pressure may be arranged on a straight line along the Y axis. Of the two pressure chamber rows formed on the pressure chamber substrate 310, the pressure chamber row located on the +X side is referred to as the first pressure chamber row. The pressure chamber row located on the -X side of the first pressure chamber row may be referred to as the "first pressure chamber row," and the pressure chamber row located on the -X side of the first pressure chamber row may be referred to as the "second pressure chamber row." be.

[0022] In addition, the pressure chamber 312 has a length along the X axis in a plan view seen from the +Z side, and a length along the Y axis. It is formed in a rectangular shape, which is longer than the length along the +Z direction. The shape of the pressure chamber 312 in plan view is not limited to a rectangle, but may be a parallelogram. The shape may be a polygon, a circle, an oval, or the like. Here, the oval shape means a rectangular shape. This refers to a shape that is based on a rectangular shape with semicircular ends in the longitudinal direction, and is also called a rounded rectangular shape or an oval shape. , egg-shaped, etc.

[0023] As shown in FIG. 2, a communication plate 315 and a nozzle plate 316 are provided on the +Z side of the pressure chamber substrate 310. 320 and a compliance substrate 345 are laminated together.

[0024] As shown in FIGS. 2, 4, and 5, the communication plate 315 is provided with a nozzle communication passage 316, a first nozzle communication passage 316, a second nozzle communication passage 316, a third nozzle communication passage 316, a fourth nozzle communication passage 316, a fifth ... A second manifold portion 317, a second manifold portion 318, and a supply communication passage 319 are formed. The first manifold portion 317 penetrates the communication plate 315 in the direction along the Z axis. The second manifold portion 318 communicates with the first manifold portion 317, and the communication plate 315 is The first manifold does not penetrate in the direction along the axis, but opens onto the +Z side surface. The second manifold portion 317 and the second manifold portion 318 are connected to a common liquid chamber through which the plurality of pressure chambers 312 communicate. The supply communication passage 319 constitutes a part of the manifold 400. 2, and one of the pressure chambers 312 in the direction along the X axis is provided independently. The end of the manifold 400 communicates with the second manifold portion 318. The ink stored in the nozzles 316 is supplied to each pressure chamber 312. The chamber 312 and the nozzle 321 are in communication with each other.

[0025] Such a communication plate 315 may be a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates. A composite substrate, a metal substrate, or the like can be used. As the metal substrate, for example, a stainless steel substrate can be used. The communicating plate 315 has a coefficient of thermal expansion that is approximately the same as that of the pressure chamber substrate 310. It is preferable to use the same material. Even if the temperature changes, the pressure chamber substrate 310 and the communication plate 3 This reduces the risk of warping of 15.

[0026] The nozzle plate 320 is located on the opposite side of the communicating plate 315 from the pressure chamber substrate 310, i.e., The nozzle plate 320 is located on the +Z side of the through plate 315. The nozzle plate 320 has a nozzle communication passage 31 A plurality of nozzles 321 are formed in communication with the pressure chambers 312 via the nozzles 6. Specifically, The nozzle plate 320 has a nozzle array in which a plurality of nozzles 321 are arranged in parallel along the Y axis. Two rows of nozzles are formed along the X axis. These two rows of nozzles correspond to a first pressure chamber row and a second pressure chamber row. The nozzles 321 correspond to the nozzles forming each nozzle row. The positions of the modules 321 and 322 are aligned along the Y axis so that they are in the same position along the X axis. The arrangement of the nozzles 321 in the nozzle plate 320 is not limited to the above arrangement. For example, the plurality of nozzles 321 may be arranged such that the nozzles 321 form each nozzle row. They may be arranged on a line along the Y axis so that their positions along the X axis are different. That is, the print head 22 of this embodiment has a plurality of nozzles 321. are positioned side by side along the Y axis in the nozzle plate 320.

[0027] The material of such a nozzle plate 320 is not particularly limited, and may be, for example, a silicon substrate, a glass substrate, or the like. A glass substrate, an SOI substrate, various ceramic substrates, and a metal substrate may be used. An organic material such as a resin may also be used. Examples of metal substrates that can be used include stainless steel substrates. It is preferable that the material of the port 320 has a thermal expansion coefficient substantially equal to that of the communicating plate 315. Therefore, when the temperature of the nozzle plate 320 and the communication plate 315 changes, the difference in the thermal expansion coefficient This can reduce the risk of warping of the nozzle plate 320 and the communication plate 315 due to the above.

[0028] The compliance substrate 345, together with the nozzle plate 320, It is located on the opposite side to the chamber substrate 310, that is, on the +Z side of the communication plate 315. The surface substrate 345 is located around the nozzle plate 320 and is formed on the communication plate 315. The openings on the +Z side of the first manifold portion 317 and the second manifold portion 318 are sealed. The compliance substrate 345 is made up of a sealing film 346 made of a flexible thin film and a metal or other and a fixed substrate 347 made of a hard material. In the area facing 400, an opening 348 is formed that is completely removed in the thickness direction. That is, one surface of the manifold 400 is sealed only by the flexible sealing film 346. The Compliance Department 349 has been established.

[0029] On the other hand, the opposite side of the pressure chamber substrate 310 from the nozzle plate 320, etc., i.e., the pressure chamber substrate A vibration plate 350 and a piezoelectric element 60 are laminated on the −Z side of 310. The vibration plate 350 is located on the +Z side of the piezoelectric element 60 in the direction along the Z axis, and Plate 310 is located on the +Z side of diaphragm 350 in the direction along the Z axis.

[0030] Furthermore, on the −Z side of the pressure chamber substrate 310, a retaining plate having approximately the same size as the pressure chamber substrate 310 is provided. The protective substrate 330 is positioned and bonded with an adhesive or the like. A holding portion 331 is formed as a space for protecting the element 60. The holding portion 331 is The protective substrate 60 is provided independently for each row of the piezoelectric elements 60 arranged in parallel along the protective substrate 60. The protection substrate 330 has two holding portions 331 arranged along the X axis. 30 is located between two holding portions 331 aligned along the X axis and penetrates in the direction along the Z axis. A through hole 332 is formed.

[0031] Moreover, on the protection substrate 330, a manifold 400 communicating with the plurality of pressure chambers 312 is provided. A case member 340 is fixed to define the force chamber substrate 310. has substantially the same shape as the above-mentioned communication plate 315 in plan view from the -Z side, and 30 and is also joined to the above-mentioned communication plate 315.

[0032] The case member 340 is formed with a housing portion 341. The housing portion 341 is formed with a pressure chamber substrate. The space has a depth that can accommodate the protective substrate 310 and the protective substrate 330. The protective substrate 330 has an opening on the 330 side that is wider than the surface of the protective substrate 330 that is bonded to the pressure chamber substrate 310. The opening surface of the accommodation portion 341 on the nozzle plate 320 side is connected to the pressure chamber base. When the plate 310 and the protection substrate 330 are housed, the plate 315 seals the space. are.

[0033] The case member 340 also has two outer sides of the storage section 341 in the direction along the X axis. A third manifold portion 342 is formed in the case member 340. The third manifold portion 342 provided in the communication plate 315 and the first manifold portion provided in the communication plate 315 are connected to each other. The manifold 400 is formed by the first manifold portion 317 and the second manifold portion 318. Such manifolds 400 are provided successively along the Y axis, and each The supply communication passage 319 that connects the pressure chamber 312 and the manifold 400 is oriented in the direction along the Y axis. are arranged side by side.

[0034] The case member 340 is connected to the manifolds 400. A supply port 344 for supplying ink is formed in the case member 340. A connection port 343 is provided in communication with the through hole 332 of the protection substrate 330 and through which the wiring substrate 420 is inserted. It is formed.

[0035] The print head 22 is connected to the ink container 9 via an ink tube or the like (not shown). 0 is taken in from the supply port 344. The path from the manifold 400 to the nozzle 321 is filled with the ink. , the integrated circuit 421 outputs a drive signal CO to each of the piezoelectric elements 60 corresponding to the pressure chambers 312. A signal based on M is supplied. This causes the piezoelectric element 60 to bend and deform. The vibration plate 350 is deformed by the shape of the vibration plate 350. The internal pressure of the nozzle 321 changes, and ink is ejected from each nozzle 321 in response to the change in the internal pressure. can be.

[0036] Next, the pressure chamber substrate 310, which includes the above-mentioned vibration plate 350 and piezoelectric element 60, The details of the configuration formed on the -Z side will be described. The print head 22 is formed on a pressure chamber substrate 31. In addition to the vibration plate 350 and the piezoelectric element 60, individual Separate lead electrode 391, common lead electrode 392, measurement lead electrode 393, and resistance wiring 4 It has 01.

[0037] As shown in FIGS. 4 to 6, the vibration plate 350 is made of a silicon oxide film provided on the pressure chamber substrate 310 side. The elastic film 351 is made of zirconia, and the zirconium oxide film is provided on the elastic film 351. and an insulating film 352. The pressure chambers 31 formed in the pressure chamber substrate 310 are The liquid flow path including 2 is formed by anisotropically etching the pressure chamber substrate 310 from the +Z side surface. The vibration plate 350 seals the opening on the +Z side surface of the pressure chamber substrate 310. That is, the pressure chambers 312 formed in the pressure chamber substrate 310 are positioned so as to stop the The surface on the -Z side of the liquid flow path is made up of a vibration plate 350 including an elastic film 351. The configuration of the moving plate 350 is not particularly limited, and for example, it may be made up of an elastic film 351 and an insulating film 35 2, or any other film other than the elastic film 351 and the insulating film 352. The diaphragm 350 may be configured to include other films such as Examples of the material include films of silicon and silicon nitride.

[0038] The piezoelectric element 60 is made up of piezoelectric elements stacked in order from the +Z side, which is the vibration plate 350 side, to the −Z side. The piezoelectric element 60 has a pole 360, a piezoelectric body 370, and an electrode 380. 60, an electrode 380, and a piezoelectric body 370, and In the direction along the Z axis where the piezoelectric body 370 is stacked, the piezoelectric body 370 is Such a piezoelectric element 60 generates a pressure change in the pressure chamber 312. It functions as a piezoelectric actuator.

[0039] Specifically, both the electrode 360 ​​and the electrode 380 are electrically connected to the wiring substrate 420. An integrated circuit mounted on the wiring board 420 is connected to one of the electrodes 360 and 380. A signal based on the drive signal COM output from the output 421 is supplied to the other of the electrodes 360 and 380. A signal of a reference potential is supplied to the wiring board 420. is a voltage between a signal based on the drive signal COM supplied from the integrated circuit 421 and a signal at the reference potential. The potential difference generated between the electrode 360 ​​and the electrode 380 causes the piezoelectric element 37 Then, in response to the deformation of the piezoelectric body 370, the vibration plate 350 deforms or vibrates. The volume of the pressure chamber 312 changes due to the deformation or vibration of the diaphragm 350. The change in internal pressure caused by the volume change is applied to the ink contained in the pressure chamber 312. As a result, the ink is ejected from the nozzle 321 via the nozzle communication passage 316. In the following description, the driving signal output from the integrated circuit 421 mounted on the wiring board 420 is A signal based on the signal COM is supplied to the electrode 360, and the reference potential of the signal COM propagates through the wiring board 420. The description will be given assuming that a signal is provided to electrode 380 .

[0040] In the following description, in the piezoelectric element 60, a voltage is applied between the electrode 360 ​​and the electrode 380. When a potential difference occurs, the portion of the piezoelectric body 370 where piezoelectric distortion occurs is called an active portion 410. The portion of the body 370 where no piezoelectric strain occurs may be referred to as the inactive portion 415. In the piezoelectric element 60, the portion where the piezoelectric body 370 is sandwiched between the electrode 360 ​​and the electrode 380 is the active portion 41. 0, and the portion where the piezoelectric body 370 is not sandwiched between the electrodes 360 and 380 is the inactive portion. In the following description, when the piezoelectric element 60 is driven, the The part that displaces in the direction of the Z axis is called the flexible part, and the part that does not displace in the direction of the Z axis is called the non-flexible part. That is, in the piezoelectric element 60, the pressure chamber 312 is The opposing portions correspond to the flexible portions, and the portions outside the pressure chamber 312 correspond to the non-flexible portions. Active section 410 may also be referred to as the active section, and inactive section 415 may also be referred to as the inactive section.

[0041] Generally, one of the electrodes 360 and 380 located in the active portion 410 is activated. The active portion 410 is configured as an independent individual electrode, and the other is configured as a common electrode common to the active portion 410. In the following description, the signal based on the drive signal COM output from the integrated circuit 421 is The electrode 360 ​​to which the signal is supplied is an individual electrode, and the signal of the reference potential propagating through the wiring board 420 The following description will be given assuming that the electrode 380 to which the signal is supplied is a common electrode.

[0042] Specifically, the electrode 360 ​​is located on the +Z side of the piezoelectric body 370, and The electrodes 360 are separated into individual electrodes for each active portion 410. The electrodes 360 are individually provided corresponding to the plurality of pressure chambers 312. In the direction of the electrode 3, the width of the electrode 3 is narrower than the width of the pressure chamber 312. The end of 60 is located inside the region facing the pressure chamber 312 in the direction along the Y axis. The end 360a on the +X side and the end 360b on the −X side of the electrode 360 ​​are respectively This is located outside the pressure chamber 312. For example, as shown in FIG. The end 360a is located on the +X side of the end 312a of the pressure chamber 312 on the +X side. The portion 360b is located closer to the -X side than the end 312b of the pressure chamber 312 on the -X side.

[0043] The material of such an electrode 360 ​​is not particularly limited, and may be, for example, platinum (Pt), iridium ( Metals such as Ir, gold (Au), and titanium (Ti), and indium oxide (ITO) Conductive materials such as conductive metal oxides such as zinc may also be used, and platinum (Pt), iridium (Ir) and the like may also be used. The material used is a laminate of multiple materials such as titanium (Ti), iridium (Ir), gold (Au), and titanium (Ti). In the following description, the electrode 360 ​​in this embodiment is made of platinum (Pt).

[0044] As shown in FIG. 3, the piezoelectric body 370 has a predetermined length along the X axis. , are provided continuously in the direction along the Y axis. The chambers 312 are provided continuously with a predetermined thickness along the direction in which they are arranged side by side. The thickness of the conductive body 370 is not particularly limited, and may be, for example, 1000 to 4000 nanometers. It is formed to a thickness of about 1 / 4 inch.

[0045] 5, the length of the piezoelectric body 370 in the direction along the X axis is The length of the pressure chamber 312 is longer than the length along the X axis, which is the longitudinal direction. On both sides of the inclined direction, the piezoelectric body 370 extends to the outside of the pressure chamber 312. As shown, the piezoelectric body 370 extends to the outside of the pressure chamber 312 in the direction along the X axis. This improves the strength of the diaphragm 350. Therefore, the risk of cracks occurring in the vibration plate 350 and the piezoelectric element 60 is reduced.

[0046] 5, in the first pressure chamber row, the end 3 on the +X side of the piezoelectric body 370 70a is located on the +X side, which is outside the end 360a of the electrode 360. The end 360a of the electrode 360 ​​is covered with the piezoelectric body 370. The end 370b on the −X side is located on the +X side, which is more inward than the end 360b of the electrode 360. That is, the end 360 b of the electrode 360 ​​is not covered with the piezoelectric body 370 .

[0047] 3 and 6, the piezoelectric body 370 has other regions corresponding to the partition walls 311. The groove portion 371 is formed in the area thinner than the other area. , is formed by completely removing the piezoelectric body 370 in the direction along the Z axis. The piezoelectric body 370 has a portion thinner than the other region, and the piezoelectric body 370 is formed on the bottom surface of the groove 371. Not only when the piezoelectric element 370 is formed thinner than other parts, but also when the piezoelectric element 370 is formed along the Z axis The length of the groove 371 in the Y-axis direction, That is, the width of the groove 371 is equal to or wider than the width of the partition wall 311. In this embodiment, the width of the groove 371 is wider than the width of the partition wall 311. The portion 371 is formed to have a rectangular shape when viewed from the -Z side. However, the shape of the groove 371 in plan view from the -Z side is not limited to a rectangular shape, and may be a polygon with pentagons or more. It may be rectangular, circular, elliptical, or the like.

[0048] By providing grooves 371 in the piezoelectric body 370, the pressure chamber 312 of the vibration plate 350 is The rigidity of the part facing the end in the direction along the diaphragm 350, that is, the arm part of the diaphragm 350, is reduced. , the piezoelectric element 60 can be displaced more effectively.

[0049] Such a piezoelectric body 370 is formed on the electrode 360 ​​and exhibits an electromechanical conversion function. Perovskite-structured crystalline film made of ferroelectric ceramic material, so-called perovskite type Examples of the material of the piezoelectric body 370 include zirconate titanate. Ferroelectric piezoelectric materials such as lead (PZT) and niobium oxide, nickel oxide or magnesium oxide are used. The metal oxides such as lead titanate (PbTiO 3), lead zirconate titanate (Pb(Zr,Ti)O3), lead zirconate (PbZr O3), lead lanthanum titanate ((Pb,La),TiO3), lead lanthanum zirconate titanate Titanium ((Pb,La)(Zr,Ti)O3) or magnesium zirconium niobate Lead titanate (Pb(Zr,Ti)(Mg,Nb)O3) can be used. The piezoelectric body 370 of this embodiment will be described as being made of lead zirconate titanate (PZT).

[0050] The material of the piezoelectric body 370 is not limited to lead-based piezoelectric materials containing lead, but may be any other material containing no lead. It is also possible to use lead-free piezoelectric materials. Examples of such lead-free piezoelectric materials include For example, bismuth ferrate (BiFeO3, abbreviated as "BFO"), barium titanate (BaT iO3), abbreviated as "BT"), potassium sodium niobate ((K,Na)(NbO3), abbreviated as "BT" "KNN"), potassium sodium lithium niobate ((K,Na,Li)(NbO3) ), potassium sodium lithium tantalate niobate ((K,Na,Li)(Nb,Ta )O3), bismuth potassium titanate ((Bi1 / 2K1 / 2)TiO3, abbreviated as "BKT" ), bismuth sodium titanate ((Bi1 / 2Na1 / 2)TiO3, abbreviated as "BNT") , bismuth manganate (BiMnO3, abbreviated as "BM"), bismuth, potassium, titanium and Complex oxides containing iron and having a perovskite structure (x[(BixK1-x)TiO3]- (1-x) [BiFeO3], abbreviated as "BKT-BF"), bismuth, iron, barium and titanium The complex oxide ((1-x)[BiFeO3]-x[B aTiO3, abbreviated as "BFO-BT") and metals such as manganese, cobalt, and chromium (1-x)[Bi(Fe1-yMy)O3]-x[BaTiO3](M Examples of the element include Mn, Co, and Cr).

[0051] As shown in FIGS. 3, 5, and 6, the electrode 380 is connected to the piezoelectric body 370 via the electrode 360. The common electrode 410 is located on the opposite side to the piezoelectric body 370 and on the −Z side of the piezoelectric body 370. That is, the electrode 380 is provided in common to the plurality of pressure chambers 312. The electrode 380 has a predetermined length along the X axis and a predetermined length along the Y axis. The electrode 380 is provided continuously over the inner surface of the groove 371, i.e., the piezoelectric The insulating film 352 is also provided on the side surface of the groove 371 of the body 370 and on the bottom surface of the groove 371. In addition, the electrode 380 is attached to only a part of the inner surface of the groove 371. It is not necessary to provide the groove 371 over the entire inner surface thereof.

[0052] 5, in the first pressure chamber row, the end 3 on the +X side of the electrode 380 80a is positioned outside the end 360a of the electrode 360 ​​covered with the piezoelectric body 370. That is, the end 380a of the electrode 380 is disposed on the +X side of the pressure chamber 312. The +X side is outside the portion 312a, and outside the end 360a of the electrode 360. In this embodiment, the end 380a of the electrode 380 is located on the +X side along the X axis. In the direction of the active portion, the active portion substantially coincides with the end 370a of the piezoelectric body 370. The edge of the +X side of 410, that is, the boundary between the active portion 410 and the inactive portion 415, is the electrode 360. The end 360a is defined by the end 360a.

[0053] On the other hand, the end 380b on the −X side of the electrode 380 is located outside the end 312b of the pressure chamber 312. The piezoelectric element 370 is located on the -X side, i.e., on the +X side, which is inside the end 370b of the piezoelectric element 370. As described above, the end 370b of the piezoelectric body 370 is more positive than the end 360b of the electrode 360. Therefore, the end 380b of the electrode 380 is located on the inner side of the electrode 360. The electrode 38 is located on the piezoelectric body 370, which is closer to the +X side than the end 360b of the electrode 38. On the −X side of the end 380b of the piezoelectric element 370, there is a portion where the surface of the piezoelectric element 370 is exposed. In this way, the end 380b of the electrode 380 is connected to the end 370b of the piezoelectric body 370 and the end 360 of the electrode 360. Therefore, the end of the active portion 410 on the -X side, That is, the boundary between the active portion 410 and the inactive portion 415 is defined by the end 380b of the electrode 380. It is determined.

[0054] The material of the electrode 380 is not particularly limited, and may be, for example, the same as the electrode 360. , platinum (Pt), iridium (Ir), gold (Au), titanium (Ti) and other metals, IT Even if conductive materials such as conductive metal oxides such as indium tin oxide, abbreviated as O, are used, Often, multiple materials such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti) are used. The electrode 380 of this embodiment may be made of iridium. The explanation will be given assuming that (Ir).

[0055] In addition, the outside of the end 380b of the electrode 380, i.e., the further end 380b of the electrode 380 On the −X side, there is a wiring portion that is in the same layer as the electrode 380 but is electrically discontinuous with the electrode 380. The wiring portion 385 is provided so as not to come into contact with the end portion 380b of the electrode 380. The piezoelectric element 370 is provided on the −X side of the piezoelectric element 370 with a gap therebetween. The wiring portion 385 is formed over the electrode 360. The wiring portion 385 is independent for each active portion 410. That is, the wiring portions 385 are arranged at predetermined intervals in the direction along the Y axis. The wiring portion 385 may be formed in a layer different from the electrode 380. However, it is preferable to form the wiring portion 385 in the same layer as the electrode 380. The manufacturing process can be simplified and costs can be reduced.

[0056] Further, individual lead electrodes 391 are connected to the electrodes 360 constituting the piezoelectric element 60. 380 are electrically connected to a common lead electrode 392 which is a common electrode for driving. The ends of the individual lead electrodes 391 and the common lead electrode 392 connected to the piezoelectric element 60 are The opposite end is electrically connected to a wiring board 420. A control unit 10, a temperature information output circuit 26, and a plurality of circuits (not shown) for connecting to the control unit 10, the temperature information output circuit 26, and a plurality of circuits (not shown) Such a wiring board 420 is, for example, an FPC (Flexible Printed Circuit) It consists of a printed circuit.

[0057] In this embodiment, the individual lead electrodes 391 and the common lead electrode 392 are connected to the protection substrate 330. The wiring board is provided with a through hole 332 formed in the wiring board. 420. The wiring board 420 is also electrically connected to the piezoelectric element 60. An integrated circuit 421 is mounted on the device to output a signal for this purpose.

[0058] In this embodiment, the individual lead electrode 391 and the common lead electrode 392 are formed in the same layer. are electrically discontinuous. The manufacturing process is simplified compared to when the common lead electrode 392 is formed separately. Of course, the individual lead electrodes 391 and the common lead electrode 39 2 may be formed from different layers.

[0059] The material of the individual lead electrode 391 and the common lead electrode 392 has electrical conductivity. There is no particular limitation as long as the material is used, and examples thereof include gold (Au), copper (Cu), titanium (Ti), and titanium. W, Nickel (Ni), Chromium (Cr), Platinum (Pt), Aluminum (A In this embodiment, the individual lead electrodes 391 and the common lead The electrode 392 will be described as being made of gold (Au). The lead electrode 392 improves the adhesion between the electrode 360, the electrode 380 and the diaphragm 350. The adhesive layer may have an adhesive layer for preventing adhesion.

[0060] The individual lead electrodes 391 are provided for each active portion 410, i.e., for each electrode 360. For example, as shown in FIG. 5, in the first pressure chamber row, the individual lead electrode 391 is 385, the piezoelectric body 370 is connected to the vicinity of the end 360b of the electrode 360 ​​provided on the outside of the piezoelectric body 370. and is drawn out in the direction along -X onto the pressure chamber substrate 310, actually onto the vibration plate 350. are.

[0061] On the other hand, as shown in FIG. 3, in the first pressure chamber row, the common lead electrode 392 is At both ends of the piezoelectric body 370 in the direction of vibration, the piezoelectric body 370 vibrates from the electrode 380 that constitutes the common electrode. The common lead electrode 392 is extended to the −X side onto the plate 350. 3 and 5, for example, in the first pressure chamber row, The extension portion 392a extends in the direction along the Y axis in a region corresponding to the end portion 312a of the pressure chamber 312. The extension portion 392b is provided in a region corresponding to the end portion 312b of the pressure chamber 312, and extends along Y The extension portions 392a and 392b are provided to extend in the direction along the axis. The active portion 410 is provided continuously in the direction along the Y axis.

[0062] Further, the extension portion 392a and the extension portion 392b are spaced apart from each other in the direction along the X axis. 2 to the outside of the pressure chamber 312. The active portion 410 is located outside the pressure chamber 312 at both ends of the pressure chamber 312 in the direction along the X axis. The extension portion 392a and the extension portion 392b apply pressure to the active portion 410. It extends to the outside of the chamber 312 .

[0063] As shown in FIG. 5, a resistive wiring 401 is provided on the −Z side surface of the diaphragm 350. The resistance wire 401 utilizes the property that the electrical resistance value changes depending on the temperature, and The material of the resistive wiring 401 is a material whose electrical resistance value is temperature dependent. The material is, for example, gold (Au), platinum (Pt), iridium (Ir), aluminum Aluminum (Al), Copper (Cu), Titanium (Ti), Tungsten (W), Nickel (Ni), Chromium (Cr) or the like can be used.

[0064] Of these, platinum (Pt) has a large change in resistance due to temperature, and is highly stable and accurate. Furthermore, platinum (Pt) has a high linearity in the change in resistance value with respect to temperature change. Therefore, platinum (Pt) is preferably used as the material for the resistive wiring 401. The wiring 401 is preferably made of platinum (Pt). In this case, the resistive wiring 401 is in the same layer as the electrode 360 ​​and is electrically discontinuous with the electrode 360. In other words, the resistive wiring 401 is formed on the −Z side surface of the diaphragm 350. The wiring pattern is laminated on the −Z side surface of the diaphragm 350 in the direction along the Z axis. The wiring pattern contains platinum (Pt).

[0065] As shown in FIG. 3, one end of the resistance wiring 401 is connected to the measurement lead electrode 393a. The other end of the resistance wiring 401 is connected to the measurement lead electrode 393b. The electrodes 393a and 393b are electrically connected to the wiring board 420. The temperature of the pressure chamber 312 detected by the anti-wire 401 varies depending on the temperature of the pressure chamber 312. A signal having a voltage value corresponding to the electrical resistance value is output from the print head 22.

[0066] In this embodiment, the resistive wiring 401 is covered with the piezoelectric body 370 and is In the direction of the arrow, the resistive wiring 401 is located between the vibration plate 350 and the piezoelectric element 370. a meandering pattern on the first pressure chamber row side located on the +X side in the direction along the X axis, and a meandering pattern on the first pressure chamber row side located on the +X side in the direction along the X axis; and a second pressure chamber row side meander pattern located on the -X side in the direction perpendicular to the first pressure chamber. The row-side meandering pattern is, when viewed from the -Z side, a pattern that communicates with each pressure chamber 312 that constitutes the first pressure chamber row. The second pressure passage 314 is positioned so as to overlap with the supply communication passage 319, and meanders in the direction along the Y axis. The chamber row side meandering pattern is connected to each pressure chamber 312 constituting the second pressure chamber row when viewed from the -Z side. The supply passage 319 is positioned so as to overlap with the supply passage 319, and snakes along the Y axis. That is, the resistance wiring 401 is connected to a first pressure chamber corresponding to a first pressure chamber row formed by a plurality of pressure chambers 312. The chamber row side meandering pattern and the second pressure chamber corresponding to the second pressure chamber row formed by the plurality of pressure chambers 312 and a chamber row side serpentine pattern.

[0067] 4 and 5, the Z-axis of the pressure chamber 312 and the resistance wiring 401 are The distance along the axis is shorter than the dimension of the pressure chamber 312 along the Z axis. In addition, for example, in the first pressure chamber row, the end 312a of the pressure chamber 312 on the +X side and the resistance wiring 4 The longest distance between the pressure chamber 312 and the pressure chamber 312 in the direction along the X axis is Therefore, the electrical resistance value of the resistance wiring 401 changes depending on the temperature change of the pressure chamber 312. It is easy to adapt and change.

[0068] Measurement lead electrodes 39 including measurement lead electrodes 393a and 393b In this embodiment, the lead electrode 3 is made of the same layer as the individual lead electrode 391 and the common lead electrode 392. However, it is formed so as to be electrically discontinuous. 3 is formed separately from the individual lead electrode 391 and the common lead electrode 392, The manufacturing process can be simplified and the cost can be reduced. 3 is formed in a layer different from the individual lead electrodes 391 and the common lead electrode 392. Good too.

[0069] The material of such measuring lead electrode 393 is not particularly limited as long as it is a conductive material. For example, gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel Ni (Ni), chromium (Cr), platinum (Pt), aluminum (Al), etc. can be used. In the following description, the measurement lead electrode 393 of this embodiment is made of gold (Au). That is, the material of the measuring lead electrode 393 in this embodiment is the same as that of the individual lead electrode 3 91 and the common lead electrode 392. The measurement lead electrode 393 is a resistance wire. An adhesive layer that improves adhesion to the wire 401 and the diaphragm 350 may be provided.

[0070] As described above, in this embodiment, the measurement lead electrode 393 is formed on the protection substrate 330. The wiring board 420 is electrically connected to the wiring board 420 through the through hole 332. As a result, the resistance wiring 401 that changes depending on the temperature of the pressure chamber 312 The electrical resistance value is output from the print head 22 via the wiring board 420.

[0071] That is, the print head 22 of the head unit 20 of this embodiment has an electrode 36 0, electrode 380, and piezoelectric body 370, In the direction along the Z axis where the layers are stacked, the piezoelectric body 370 is located between the electrode 360 ​​and the electrode 380. a piezoelectric element 60 that is driven by receiving a drive signal COM, and a The vibration plate is located on the +Z side, which is one side of the direction along the axis, and is deformed by driving the piezoelectric element 60. 350, and is located on the +Z side, which is one side of the diaphragm 350 in the direction along the Z axis, and A pressure chamber 312 is provided in which gas is stored and the volume of which changes with the deformation of the vibration plate 350. The pressure chamber substrate 310 has a nozzle that ejects ink in response to changes in the volume of the pressure chamber 312. The pressure sensor 321 is located on the −Z side of the diaphragm 350 in the direction along the Z axis. and a resistance wiring 401 for acquiring a temperature corresponding to the temperature of the chamber 312.

[0072] 3. Configuration of the liquid ejection device Next, the functional configuration of the liquid ejection device 1 will be described. As shown in FIG. 7, the liquid ejection device 1 includes a control unit 10, a head unit 11, a 20, a carriage motor 31, a transport motor 41, an encoder sensor 92, and and an alarm circuit 94.

[0073] The control unit 10 includes a drive circuit 50, a reference voltage output circuit 52, and a control circuit 100. The control circuit 100 is composed of a processing circuit such as a CPU or FPGA and a semiconductor memory. The control circuit 100 includes a memory circuit. The control circuit 100 is connected to the outside of the liquid ejection device 1 so as to be able to communicate with the outside. An image information signal including image data and the like is input from an external device such as a host computer. The control circuit 100 controls the liquid ejection device 1 based on the input image information signal. and outputs various signals to the corresponding components.

[0074] As a specific example, the control circuit 100 receives an encoder sensor signal in addition to the image information signal described above. The head unit 20 receives the scanning position of the carriage 21 from the sensor 92. The control circuit 100 receives the position detection signal PS. Based on this, the scanning position of the carriage 21 and the print head mounted on the carriage 21 are The control circuit 100 then determines the scanning position of the head unit 20 including the input 22. The image information signal to be input and various signals corresponding to the grasped scanning position of the head unit 20 are transmitted. Generate and output to the corresponding configuration.

[0075] In detail, the control circuit 100 controls the head unit 20 in accordance with the scanning position of the head unit 20. Generates a control signal Ctrl-C to control the movement of the carrier 20 along the scan axis. This outputs the signal to the carriage motor 31, which then operates the carriage motor 31. The movement of the head unit 20 mounted on the scanner 21 along the scanning axis and the scanning position are controlled. The control circuit 100 also generates a control signal Ctrl-T for controlling the transport of the medium P. Then, the signal is output to the transport motor 41. This causes the transport motor 41 to operate, and the transport of the medium P The control signal Ctrl-C is sent to a driver (not shown) to control the movement along the feed direction. After being converted into a signal through a circuit, the signal may be input to the carriage motor 31. Ctrl-T is converted into a signal through a driver circuit (not shown) and then driven by the transport motor 41 may be entered into

[0076] The control circuit 100 also controls the image information signal input from the external device and the head unit 2. 0 scanning position, and a control signal Ctrl- for controlling the head unit 20 based on H, the print data signals SI1 to SIn, the change signal CH, the latch signal LAT, and A clock signal SCK is generated and output to the head unit 20.

[0077] Furthermore, the control circuit 100 includes a temperature measuring device for acquiring information on the temperature of the head unit 20. The control circuit 100 generates a data acquisition request signal TD and outputs it to the head unit 20. The temperature information signal TD includes information about the temperature of the head unit 20 in response to the temperature acquisition request signal TD. The control circuit 100 receives the temperature information signal TI. The temperature of the drive unit 20 is detected, and the control signal Ctrl- H, Ctrl-C, and Ctrl-T are corrected and output to the corresponding configuration. The temperature of the ink jet head 22 is measured by the liquid ejection device 1 and the head 22 in response to the temperature information signal TI. As a result, the operation of the liquid ejection device 1 and the head unit 20 Therefore, the ejection accuracy of the ink ejected from the nozzle is improved.

[0078] The control circuit 100 also generates a control signal Ctrl-H as a basic drive signal, which is a digital signal. The drive circuit 50 generates a drive signal dA and outputs it to the drive circuit 50. The drive circuit 50 outputs the drive signal COM to the A drive signal COM having a signal waveform defined by the drive signal dA is generated, and the drive signal COM is output to the head unit 2. Output to 0.

[0079] Specifically, the basic drive signal dA output from the control circuit 100 is input to the drive circuit 50. The driving circuit 50 converts the inputted basic driving signal dA into a digital / analog signal, and then converts it into an analog signal. The converted analog signal is amplified by class D to generate the drive signal COM, which is then sent to the head unit 2. 0. That is, the control circuit 100 outputs the control signal corrected based on the temperature information signal TI. The driving circuit 50 outputs the basic driving signal dA as the signal Ctrl-H, and the temperature information signal TI The drive signal COM having a corrected signal waveform according to the base drive signal dA corrected based on the Here, the basic drive signal dA output by the control circuit 100 is a signal wave of the drive signal COM. The basic drive signal dA is a digital signal that defines the shape of the drive signal CO. It is sufficient to specify the signal waveform of M, and it may be an analog signal. The circuit 50 amplifies the signal waveform defined by the basic drive signal dA in a class A, class B, or class AB manner. The drive signal COM may be generated by amplifying the signal.

[0080] As described above, the drive circuit 50 generates and outputs the drive signal COM based on the basic drive signal dA. At this time, the basic drive signal dA input to the drive circuit 50 is The basic drive signal dA to be output is also determined based on the temperature information signal TI. Therefore, the driving circuit 50 corrects the temperature of the head unit 20. The drive signal COM corrected based on the above is output.

[0081] The reference voltage output circuit 52 generates a reference voltage signal VBS and outputs it to the head unit 20. This reference voltage signal VBS is a signal having a constant voltage value that serves as a reference for driving the piezoelectric element 60. The voltage of the reference voltage signal VBS is supplied to the common electrode 380. The value may be, for example, a constant signal at ground potential, or at a potential such as 5.5V or 6V. It may also be a constant signal.

[0082] The control circuit 100 also includes a drive circuit 50, a reference voltage output circuit 52, and a head unit A control signal Ctrl-M is generated to notify the user of the operating status of the control signal Ctrl-M. The notification circuit 94 notifies the user of information corresponding to the control signal Ctrl-M. This notifies the user of the operating status of the liquid ejection device 1. The information may be displayed by text or images, or by sound. It may also be a speaker that announces the information.

[0083] The head unit 20 includes a plurality of print heads 22, namely, print heads 22-1 to 22-n, a temperature information output circuit 26, and a temperature detection circuit 28. Each of the nodes 22-1 to 22-n includes a drive signal selection circuit 200, a temperature detection circuit 250, and and a plurality of piezoelectric elements 60.

[0084] The print head 22-1 receives a print data signal SI1 output from the control circuit 100, A shift signal CH, a latch signal LAT, a clock signal SCK, a drive signal COM, and a reference voltage A signal VBS is input. A clock signal SCK and a line are input to the print head 22-1. The latch signal LAT, the change signal CH, the print data signal SI1, and the drive signal COM are The signal is input to the signal selection circuit 200.

[0085] The drive signal selection circuit 200 receives the input clock signal SCK, latch signal LAT, The signal wave included in the drive signal COM is generated based on the change signal CH and the print data signal SI1. By selecting or not selecting the shape, the drive signals corresponding to the plurality of piezoelectric elements 60 are generated. Then, the drive signal selection circuit 200 generates the drive signal VOUT. , one end of each of the corresponding piezoelectric elements 60, and each of the electrodes 360 which are individual electrodes. At this time, the other end of the plurality of piezoelectric elements 60 is connected to the electrode 38 which is a common electrode. A reference voltage signal VBS is input to all of the piezoelectric elements 60. Each of these is a drive signal VOUT input to the electrode 360 ​​and a base signal VB input to the electrode 380. As a result, the piezoelectric element 60 is displaced by an amount corresponding to the displacement of the piezoelectric element 60. The ink is ejected from the corresponding nozzles 321 of the print head 22-1.

[0086] That is, the print head 22-1 receives the drive signal COM and ejects ink. At least a part of the drive signal selection circuit 200 is programmed as the integrated circuit 421 described above. It may be mounted on the wiring board 420 of the print head 22-1.

[0087] The temperature detection circuit 250 of the print head 22-1 detects the temperature of the print head 22- The temperature detection circuit 250 detects the temperature of the print head 22-1. The head temperature signal TC1 corresponding to the temperature is output to the temperature information output circuit 26. The detection circuit 250 is partly provided in the print head 22-1 and partly provided in the print head 22-2. It may be provided outside the print head 22-1. The part of the temperature detection circuit 250 thus formed corresponds to the resistive wiring 401 described above. The temperature detection circuit 250 outputs a head temperature signal T corresponding to the temperature of the print head 22-1. The voltage value of C1 changes according to the resistance value of the resistive wiring 401, which changes with temperature. Then, the voltage value of the head temperature signal TC1 output by the temperature detection circuit 250 is The temperature of the print head 22-1 is determined depending on the temperature of the pressure chamber 312 of the print head 22-1. It changes.

[0088] The print heads 22-2 to 22-n have different input and output signals. It has the same configuration as the print head 22-1 and performs the same operations. The print head 22-i (i is any one of 2 to n) receives a clock signal SCK, a latch signal signal LAT, change signal CH, print data signal SIi, drive signal COM, and reference voltage signal Then, the drive signal selection circuit 20 of the print head 22-i receives the signal VBS. 0 is the input clock signal SCK, latch signal LAT, change signal CH, and print The signal waveform of the drive signal COM is selected or not selected based on the data signal SIi. Then, a drive signal VOUT corresponding to each of the plurality of piezoelectric elements 60 is generated, and the corresponding piezoelectric The print head 22-i has a plurality of piezoelectric elements. A reference voltage signal VBS is commonly input to the electrode 380 of the element 60. The print head 22-i has a plurality of piezoelectric elements 60 that are driven, and in response to the driving of the piezoelectric elements 60, The amount of ink is ejected from the nozzle 321 of the print head 22-i. The print heads 22-2 to 22-n also receive the drive signal COM and eject ink. do.

[0089] The temperature detection circuit 250 of the print head 22-i detects the temperature of the print head 22-i. The head temperature signal TCi having a voltage value corresponding to the temperature of i is output to the temperature information output circuit 26. At least a part of the drive signal selection circuit 200 of the print head 22-i is The integrated circuit 421 is mounted on the wiring board 420 of the print head 22-i. At least a part of the temperature detection circuit 250 of the print head 22-i is the above-mentioned resistor wiring. The line 401 is provided on the print head 22-i.

[0090] In the following description, the print heads 22-1 to 22-n will not be distinguished from one another. The print head 22 receives a clock signal SCK, a latch signal LAT, and a change signal C H, a print data signal SI as print data signals SI1 to SIn, and a drive signal COM. , and the reference voltage signal VBS are input. The temperature detection circuit 250 outputs a head temperature signal TC The following description will be given on the assumption that head temperature signals TC as TC1 to TCn are output.

[0091] The temperature detection circuit 28 detects the temperature of the head unit 20 including the print heads 22-1 to 22-n. The temperature detection circuit 28 then outputs a unit voltage value corresponding to the detected temperature. The temperature detection circuit 28 converts the generated unit temperature signal TH into temperature information. The temperature detection circuit 28 outputs the temperature information to the information output circuit 26 and the control circuit 100. The resistance value of thermistor element changes depending on the temperature change of the board unit 20. can be.

[0092] The temperature information output circuit 26 outputs the temperature information from each of the print heads 22-1 to 22-n. The temperature signals TC1 to TCn, the unit temperature signal TH output by the temperature detection circuit 28, and the control The temperature acquisition request signal TD output by the control circuit 100 and the drive signal C output by the drive circuit 50 In response to OM, a temperature information signal TI is generated and output to the control circuit 100.

[0093] Specifically, the temperature information output circuit 26 receives a temperature acquisition request signal from the control circuit 100. The head temperature signal TC is selected from the head temperature signals TC1 to TCn according to the signal TD, and the The selected head temperature is set at a timing according to the voltage value of the drive signal COM output by the circuit 50. A digital signal corresponding to the signal TC is acquired. The acquired digital signal is then used as the unit temperature. The temperature information signal TI is output to the control circuit 100 in accordance with the temperature signal TH. That is, the temperature information output circuit 26 outputs the temperature information of the print heads 22-1 to 22-n. The head temperature signals TC1 to TCn corresponding to the temperature are acquired. The temperature information signal TI is generated in accordance with the signals TC1 to TCn and output to the control circuit 100. The configuration and operation of the temperature information output circuit 26 will be described in detail later.

[0094] 4. Signal waveform of drive signal COM and configuration of drive signal selection circuit Next, the configuration and operation of the drive signal selection circuit 200 of the print head 22 will be described. As described above, the drive signal selection circuit 200 of the print head 22 selects the clock based on the clock signal SCK, the print data signal SI, the latch signal LAT, and the change signal CH. By selecting or not selecting the signal waveform included in the drive signal COM, the drive signal VOU T is generated and output to the corresponding piezoelectric element 60. In explaining the operation, first, during the period when ink is ejected onto the medium P, An example of the waveform of the drive signal COM input to the signal selection circuit 200 will now be described. In the following description, the period during which ink is ejected onto the medium P may be referred to as the ejection period. .

[0095] FIG. 8 is a diagram showing an example of the signal waveform of the drive signal COM during the ejection period. As shown in the figure, during the discharge period, the drive signal COM is latched after the latch signal LAT rises. The trapezoidal waveform Adp is placed in the period t1 until the change signal CH rises, and It is placed in the period t2 from when the signal CH rises to when the next change signal CH rises. The trapezoidal waveform Bdp and the latch signal LAT rise after the change signal CH rises. The trapezoidal waveform Cdp is arranged in the period t3 until the predetermined amount The trapezoidal waveform Bdp is a signal waveform that drives the piezoelectric element 60 to eject ink. This is a signal waveform that drives the piezoelectric element 60 so that a smaller amount of ink is ejected than the fixed amount, and is a trapezoidal waveform. The waveform Cdp is a signal waveform that drives the piezoelectric element 60 to such an extent that ink is not ejected. Here, when the trapezoidal waveform Cdp is supplied to the corresponding piezoelectric element 60, the corresponding nozzle opening The ink near the nozzle opening is vibrated to reduce the risk of the ink viscosity increasing near the nozzle opening. This is the signal waveform for

[0096] In addition, the trapezoidal waveforms Adp, Bdp, and Cdp have their respective start and end timings. The voltage value in each waveform is the same as the voltage Vc. , Bdp, and Cdp each start and end at voltage Vc.

[0097] In the following description, when a trapezoidal waveform Adp is supplied to the piezoelectric element 60, the ejection A predetermined amount of ink is called a medium amount, and when a trapezoidal waveform Bdp is supplied to the piezoelectric element 60, In some cases, an amount of ink that is smaller than the predetermined amount to be ejected may be referred to as a small amount. In addition, when a trapezoidal waveform Cdp is supplied to the piezoelectric element 60, the node corresponding to the piezoelectric element 60 The action of vibrating the ink near the nozzle opening to prevent the ink viscosity from increasing is called micro-vibration. The signal waveform of the drive signal COM shown in FIG. 8 is an example and is not intended to be limiting. It is not possible to determine the size of the ink droplets, but rather it is possible to determine the size of the ink droplets depending on the properties of the ink to be ejected and the material of the medium P on which the ink will land. Therefore, various waveform combinations may be used.

[0098] Then, in a cycle tp including periods t1, t2, and t3, the drive signal selection circuit 200 The trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM are selected or not selected. As a result, the drive signal selection circuit 200 selects the drive signal for each of the plurality of nozzles 321 in the period tp. That is, the drive signal selection circuit 200 controls the amount of ink ejected from the peripheral The dot size formed on the medium P during the period tp is controlled. In a period tp including the period, dots of a predetermined size are formed on the medium P. The period tp at which dots are formed corresponds to the dot formation period.

[0099] Next, the signal waveform included in the drive signal COM is selected or deselected to generate the drive signal VO The configuration and operation of the drive signal selection circuit 200 that generates the UT will be described. 9 is a diagram showing the configuration of the drive signal selection circuit 200. As shown in FIG. 0 has a selection control circuit 210 and a plurality of selection circuits 230, the number of which is the same as the number of piezoelectric elements 60. In the following description, it is assumed that the print head 22 has p piezoelectric elements 60. That is, the drive signal selection circuit 200 has p selection circuits 230.

[0100] The selection control circuit 210 receives a clock signal SCK, a print data signal SI, a latch signal LA, The selection control circuit 210 receives the shift register T and the change signal CH. A set of a switch (S / R) 212, a latch circuit 214, and a decoder 216 controls p piezoelectric elements. That is, the drive signal selection circuit 200 is provided corresponding to each of the p systems 60. The signal processing circuit includes a soft register 212, p latch circuits 214, and p decoders 216. .

[0101] The print data signal SI is input to the selection control circuit 210 in synchronization with the clock signal SCK. The print data signal SI is also divided into "large dot LD", "medium dot MD", and "small dot S". 2-bit print data [SIH,S IL] is included in serial corresponding to each of the p piezoelectric elements 60. The print data [SIH, SIL] to be included is p shift levels corresponding to p piezoelectric elements 60. Specifically, p shift registers corresponding to the piezoelectric elements 60 are held in the register 212. The input print data signal S is serially input. I is transferred to the subsequent shift register 212 in sequence in accordance with the clock signal SCK. The print data [SIH, SIL] is then held in the corresponding shift register 212. This causes the clock signal SCK to stop. The data [SIH, SIL] is held in the corresponding shift register 212. A print data signal SI is input to distinguish p shift registers 212. The stages are denoted as stage 1, stage 2, ..., stage p in order from the upstream side.

[0102] Each of the p latch circuits 214 latches the corresponding shift register at the rising edge of the latch signal LAT. The print data [SIH, SIL] held in the register 212 is latched all at once. The print data [SIH, SIL] latched by the latch circuit 214 is sent to the corresponding decoder. 10 is a diagram showing an example of the decoding content in the decoder 216. The decoder 216 receives the input signals in each of the periods t1, t2, and t3. It outputs a selection signal S of a logic level specified by the print data [SIH, SIL]. For example, When print data [SIH, SIL]=[1, 0] is input to the decoder 216, The reader 216 sets the logic level of the selection signal S to H, L, L during periods t1, t2, and t3. Output as a level.

[0103] The selection signal S output by the decoder 216 is input to the selection circuit 230. The drive signals 30 are provided in correspondence with the p piezoelectric elements 60. The selection circuit 200 has p selection circuits 230, the same number as the p piezoelectric elements 60. 11 is a diagram showing the configuration of the selection circuit 230. As shown in FIG. 11, the selection circuit 230 The OT circuit includes an inverter 232 and a transfer gate 234 .

[0104] The selection signal S is input to the positive control terminal of the transfer gate 234, which is not marked with a circle. The logic level is inverted by inverter 232 and then The signal is also input to the negative control terminal marked with a circle at the transfer gate 234. The drive signal COM is supplied to the input terminal of the transfer gate 234. When a selection signal S of H level is input, the power gate 234 connects the input terminal and the output terminal. When a low-level selection signal S is input, the input terminal and the output terminal are not connected. That is, when the logic level of the selection signal S is H level, the transfer gate 234 When the logic level of the selection signal S is When the signal is at the L level, the signal waveform included in the drive signal COM is not output from the output terminal. The drive signal selection circuit 200 selects the output of the transfer gate 234 of the selection circuit 230. The signal output to the terminal is output as the drive signal VOUT.

[0105] Here, the operation of the drive signal selection circuit 200 will be described with reference to FIG. FIG. 10 is a diagram for explaining the operation of the drive signal selection circuit 200. The print data signal SI is The serial signal is input to the selection control circuit 210 in synchronization with the clock signal SCK. The print data signal SI is synchronized with the clock signal SCK and is supplied to the p piezoelectric elements 60. Then, the clock signal SCK When the input of the signal P stops, the shift register 212 receives the signals P corresponding to each of the p piezoelectric elements 60. The print data signal SI is stored in the shift register. The signals are input in the order corresponding to the p-th, . . . , 2-th, and 1-th stages of the piezoelectric elements 60 of the register 212.

[0106] When the latch signal LAT rises, each of the latch circuits 214 The print data [SIH, SIL] held in the register 212 is latched all at once. LT1, LT2, ..., LTp shown in Figure 12 are shift registers of 1st stage, 2nd stage, ..., pth stage. The print data [SIH, SI] latched by the latch circuit 214 corresponding to the L] is shown.

[0107] The decoder 216 generates the dots specified by the latched print data [SIH, SIL]. In each of the periods t1, t2, and t3, the logic level of the selection signal S is 12. Then, the selection circuit 230 selects the signal output by the decoder 216. The signal waveform included in the drive signal COM is selected or not selected depending on the logic level of the selection signal S. By doing so, the drive signal VOUT is generated.

[0108] Specifically, print data [SIH, SIL]=[1, 1] is input to the decoder 216. When this signal is input, the decoder 216 sets the logic level of the selection signal S to As a result, the selection circuit 230 outputs a trapezoidal waveform signal during the period t1. Adp is selected, and trapezoidal waveform Bdp is selected in period t2, and trapezoidal waveform Bdp is selected in period t3. As a result, the drive signal selection circuit 200 does not select the large dot LD. The inverter outputs a drive signal VOUT.

[0109] When the drive signal VOUT corresponding to the "large dot LD" is supplied to the piezoelectric element 60, during the period A medium amount of ink is ejected during period t1, and a small amount of ink is ejected during period t2. In the period t3, no ink is ejected. When a large amount of ink and a small amount of ink land on the medium P and combine, a "large dot LD" is formed on the medium P. " is formed.

[0110] Also, when print data [SIH, SIL]=[1, 0] is input to the decoder 216, In this case, the decoder 216 sets the logic level of the selection signal S to H during periods t1, t2, and t3. As a result, the selection circuit 230 selects the trapezoidal waveform Adp In the period t2, the trapezoidal waveform Bdp is not selected, and in the period t3, the trapezoidal waveform Cd As a result, the drive signal selection circuit 200 does not select the drive signal p corresponding to the "medium dot MD". The inverter outputs a driving signal VOUT.

[0111] When the drive signal VOUT corresponding to the "medium dot MD" is supplied to the piezoelectric element 60, A medium amount of ink is ejected during period t1, no ink is ejected during period t2, and the expected amount of ink is During the interval t3, no ink is ejected. When the ink droplets land on the medium P, a "medium dot MD" is formed on the medium P.

[0112] Also, when print data [SIH, SIL]=[0, 1] is input to the decoder 216, In this case, the decoder 216 sets the logic level of the selection signal S to L, As a result, the selection circuit 230 selects the trapezoidal waveform Adp during the period t1. In the period t2, the trapezoidal waveform Bdp is selected, and in the period t3, the trapezoidal waveform Cd As a result, the drive signal selection circuit 200 does not select the drive signal p corresponding to the "small dot SD". The inverter outputs a driving signal VOUT.

[0113] When the drive signal VOUT corresponding to the "small dot SD" is supplied to the piezoelectric element 60, during the period During period t1, no ink is ejected, and during period t2, a small amount of ink is ejected. During the interval t3, no ink is ejected. When the droplets land on the medium P, "small dots SD" are formed on the medium P.

[0114] Also, when print data [SIH,SIL]=[0,0] is input to the decoder 216, In this case, the decoder 216 sets the logic level of the selection signal S to L, As a result, the selection circuit 230 selects the trapezoidal waveform Adp during the period t1. is not selected, the trapezoidal waveform Bdp is not selected in the period t2, and the trapezoidal waveform C As a result, the drive signal selection circuit 200 selects the drive signal corresponding to "non-recording ND". Outputs the signal VOUT.

[0115] When the drive signal VOUT corresponding to "non-recording ND" is supplied to the piezoelectric element 60, Ink is not ejected during period t1, ink is not ejected during period t2, and ink is not ejected during period t3. Therefore, no dots are formed on the medium P, which is called "non-printing ND." At this time, the corresponding piezoelectric element 60 receives a drive signal VOUT containing a trapezoidal waveform Cdp. Therefore, the micro vibration is performed. As a result, the opening of the corresponding nozzle 321 This reduces the risk of the ink viscosity increasing in the vicinity of the portion.

[0116] As described above, the drive signal selection circuit 200 selects the drive signal COM output from the drive circuit 50. By selecting or deselecting the signal waveform, the drive signal VOUT is generated and the corresponding piezoelectric element is driven. Then, a printer that ejects ink based on the drive signal VOUT is output to the printer 60. The head 22 can also be considered to eject ink based on the drive signal COM.

[0117] 5. Temperature detection circuit configuration Next, the configuration of the temperature detection circuit 250 will be described. 13 is a diagram showing an example of the configuration of a temperature detection circuit 250. 54. The resistor 254 is connected to the resistor wiring 401 and the measurement lead electrode 393. a, 393b. That is, in the temperature detection circuit 250, at least the resistor 254 The temperature detection circuit 250 is provided in the print head 22. It may be provided on the head 22.

[0118] A voltage signal VDD having a constant voltage value is supplied to one end of the resistor 252. The other end of the resistor 254 is connected to a measurement lead electrode 393a The other end of the resistor 254 is electrically connected to the measurement resistor included in the resistor 254. The ground electrode 393b is supplied with a ground potential. The voltage value generated at the connection point between the other end of the resistor 252 and one end of the resistor 254 is used as the head temperature signal. That is, the temperature detection circuit 250 outputs the voltage signal VDD as a voltage signal TC. The voltage signal obtained by dividing the resistance of the resistor wiring 401 and the resistance of the resistor wiring 402 is used as the head temperature signal TC. and output.

[0119] As described above, the resistance value of the resistive wiring 401 is determined by the temperature of the print head 22 and the pressure. The resistance 254 including the resistance wiring 401 changes depending on the temperature of the chamber 312. The resistance wiring 401 functions as a thermistor element whose resistance value changes depending on the temperature. The resistance value changes depending on the temperature of the print head 22 and the temperature of the pressure chamber 312. Therefore, the voltage value of the head temperature signal TC output by the temperature detection circuit 250 is also The temperature of the pressure chamber 312 changes depending on the temperature of the pressure chamber 312. That is, the temperature detection circuit 250 is the temperature of the print head 22, and the voltage value changes depending on the temperature of the pressure chamber 312. A head temperature signal TC is output.

[0120] In the temperature detection circuit 250 of this embodiment, the resistor 252 that divides the voltage signal VDD , 254, the resistor 254 on the low potential side is connected to the resistance wiring 401 and the measurement lead electrode 393a, 393b, the resistor 252 on the high potential side is The temperature sensor may be configured to include the wire 401 and the measurement lead electrodes 393a and 393b. The power detection circuit 250 may be configured to include multiple resistance elements in addition to the resistors 252 and 254. good.

[0121] 6. Temperature information output circuit configuration Next, the configuration and operation of the temperature information output circuit 26 will be described. 1 is a diagram showing an example of the configuration of the output circuit 26. The temperature information output circuit 26 receives temperature information from the control circuit 100. Based on the temperature acquisition request signal TD input from the At least one of the head temperature signals TC1 to TCn input from each of the The selected head temperature signal TC is acquired at a timing determined by the drive signal COM. The temperature information output circuit 26 then receives the acquired head temperature signal TC and the temperature information from the temperature detection circuit 28. The temperature of the print head 22 is determined based on the unit temperature signal TH input from the A temperature information signal TI is generated and output to the control circuit 100.

[0122] As shown in FIG. 14, the temperature information output circuit 26 includes a control circuit 500, a multiplexer 5 10, amplifier circuits 520, 550, A / D converters 530, 560, memory circuit 570, It includes a comparison circuit 580 and a timing control circuit 590 .

[0123] The multiplexer 510 receives the data output from each of the print heads 22-1 to 22-n. The head temperature signals TC1 to TCn are input to the multiplexer 510. The multiplexer 510 also receives the select signal Sel output by the control circuit 500. According to the input select signal Sel, one of the head temperature signals TC1 to TCn is selected. The selected temperature is selected and output as the selected temperature signal STC.

[0124] The selected temperature signal STC output from the multiplexer 510 is input to the amplifier circuit 520. The amplifier circuit 520 amplifies the voltage value of the input selected temperature signal STC. A width head temperature signal ATC is generated and output.

[0125] The A / D converter 530 receives the amplified head temperature signal ATC output from the amplifier circuit 520. and the enable signal EN1 output by the control circuit 500. The counter 530 receives an enable signal EN1 that enables the operation. The voltage value of the amplification head temperature signal ATC is acquired, and a digital signal corresponding to the acquired voltage value is output. The digital temperature information dtc is output to the control circuit 500. The inverter 530 operates at the timing when the enable signal EN1 that enables operation is input. In this case, the head temperature signal TC selected by the multiplexer 510 is input to the amplifier circuit 52. Digital temperature information dt corresponding to the voltage value of the amplified head temperature signal ATC amplified by 0 c) at the timing when an enable signal EN1 that enables the operation is input, The printhead temperature signal TC selected by the multiplexer 510 is The digital temperature information dtc corresponding to the temperature of the node 22 is generated and output to the control circuit 500.

[0126] In the following description, the A / D converter 530 detects the rising edge of the enable signal EN1. The following description will be given assuming that the operation is enabled at the rising edge. The amplification head temperature signal ATC input at the rising edge of the enable signal EN1 is The digital temperature information dtc is generated by converting it into a digital signal and outputting it to the control circuit 500. The A / D converter 530 detects the falling edge of the enable signal EN1. In this case, the A / D converter 530 may be enabled by the enable signal. The amplified head temperature signal ATC input at the falling edge of signal EN1 is converted to a digital signal. The digital temperature information dtc converted into the digital temperature information dtc is output to the control circuit 500.

[0127] The amplifier circuit 550 receives the unit temperature signal TH output from the temperature detection circuit 28. The amplifier circuit 520 amplifies the voltage value of the input unit temperature signal TH. Generates and outputs a unit temperature signal ATH.

[0128] The A / D converter 560 receives the amplification unit temperature signal AT H and the enable signal EN2 output by the control circuit 500. When an enable signal EN2 that enables operation is input, the controller 560 The voltage value of the amplifier unit temperature signal ATH is acquired, and a digital signal corresponding to the acquired voltage value is output. The signal is generated and output as digital temperature information dth to the control circuit 500. The / D converter 560 operates at the timing when the enable signal EN2 that enables operation is input. In this case, the temperature detection circuit 28 generates digital temperature information dth according to the detected temperature. and outputs it to the control circuit 500.

[0129] In the following description, the A / D converter 560 detects the rising edge of the enable signal EN2. The following description will be given assuming that the operation is enabled at the rising edge. Amplifier unit temperature signal ATH input at the rising edge of enable signal EN2 is converted into a digital signal to generate digital temperature information dth, which is output to the control circuit 500. The A / D converter 560 detects the falling edge of the enable signal EN2. In this case, the A / D converter 560 is enabled. The amplifier unit temperature signal ATH input at the falling edge of the signal EN2 is converted to digital The converted digital temperature information dth is output to the control circuit 500 .

[0130] The drive signal COM is input to the comparison circuit 580. The comparison circuit 580 compares the drive signal COM input The voltage value of the COM signal is compared with a predetermined voltage value, and the logic level changes depending on the comparison result. A comparison result signal Vcr is output.

[0131] The timing control circuit 590 receives the comparison result signal Vcr output by the comparison circuit 580 and the control The timing control circuit 590 receives the clock signal CK output from the timing control circuit 500. acquires the logic level of the comparison result signal Vcr in synchronization with the clock signal CK, A timing control signal Tgi having a logic level corresponding to the comparison result signal Vcr is generated. The timing control circuit 590 outputs the generated timing control signal Tgi to the control circuit 500. Output.

[0132] Here, the comparison circuit 580 and the timing control circuit 590 will be described in detail. 5 is a diagram showing an example of the configuration of the comparison circuit 580 and the timing control circuit 590.

[0133] The comparison circuit 580 includes a comparator 582 and resistors 584 and 586. The drive signal COM is input to one end of the resistor 584. The other end of the resistor 584 is connected to one end of a resistor 586. The other end of resistor 586 is electrically connected to ground potential. The connection point between the other end of the resistor 584 and one end of the resistor 586 is the positive input of the comparator 582. The negative input terminal of the comparator 582 is electrically connected to the threshold voltage The comparator 582 receives a signal Vth and determines whether the voltage value at the positive input terminal is When the voltage value at the + input terminal is greater than the voltage value at the - input terminal, it becomes H level, and when the voltage value at the + input terminal is greater than the voltage value at the - input terminal, it becomes H level. When the voltage at the output terminal is smaller than the voltage at the output terminal, a comparison result signal Vcr is generated that becomes L level. Output.

[0134] In the comparison circuit 580 configured as above, the resistors 584 and 586 are connected to the drive signal C The comparator 582 divides the attenuated drive signal COM. The voltage value is compared with the voltage value of the threshold voltage signal Vth, and a comparison result signal Vcr is generated according to the comparison result. In other words, resistors 584 and 586 determine the attenuation rate of the drive signal COM. Then, the logic level of the comparison result signal Vcr output by the comparator 582 is switched. The voltage value of the drive signal COM is set. When the voltage value of the signal COM is a predetermined voltage value, the voltage is set to be the threshold voltage signal Vth. As a result, the comparison circuit 580 determines whether the voltage value of the drive signal COM is greater than a predetermined voltage value. When the voltage value of the drive signal COM is smaller than the predetermined voltage value, it becomes H level. In the following description, the above-mentioned The logic level of the comparison result signal Vcr output by the comparison circuit 580 is changed. The predetermined voltage value of the drive signal COM to which the drive signal COM is changed is called a changeover voltage Vch.

[0135] That is, the comparison circuit 580 compares the voltage value of the drive signal COM with the switching voltage Vch, When the voltage value of the drive signal COM is greater than the voltage value of the switching voltage Vch, it becomes H level. A ratio that becomes L level when the voltage value of the drive signal COM is smaller than the voltage value of the switching voltage Vch. The comparison circuit 580 outputs a comparison result signal Vcr. The comparator 5 may include a plurality of resistor elements for dividing the threshold voltage signal Vth. In the case where 82 can operate without attenuating the voltage value of the drive signal COM, the comparison circuit 580 may not include resistors 584 and 586.

[0136] The timing control circuit 590 includes D-type flip-flops 592 and 594 and an OR circuit 599. The data input terminal D1 of the D-type flip-flop 592 receives the output of the comparison circuit 580. The comparison result signal Vcr is input to the clock input terminal of the D-type flip-flop 592. The clock signal CK output by the control circuit 100 is input to the slave CLK1. The flip-flop 592 receives the clock signal CK input to the clock input terminal CLK1. At the rising edge of A data signal Do1 is generated according to the rule and output from the data output terminal Q1.

[0137] The data input terminal D2 of the D-type flip-flop 594 receives the ratio output from the comparison circuit 580. The comparison result signal Vcr is input to the clock input terminal CLK of the D-type flip-flop 594. 2 receives a signal whose logic level is an inverted version of the clock signal CK output by the control circuit 100. The D-type flip-flop 594 receives the clock signal input to the clock input terminal CLK2. The logic level of the clock signal CK is inverted and the rising edge of the signal is inverted. At the falling edge of the logic level of the clock signal CK output by A data signal Do2 is generated according to the logic level of the input comparison result signal Vcr, and the data Output is from output terminal Q2.

[0138] The OR circuit 596 receives the data signal Do1 output from the D-type flip-flop 592, and , the data signal Do2 output by the D-type flip-flop 594 is input. 6 indicates that the logic levels of both the input data signal Do1 and the data signal Do2 are at the L level. When the data signal Do1 and the data signal Do2 are low, the signal goes to L level. A timing control signal Tgi that is at H level when at least one of the logic levels is at H level is The timing control signal Tgi output by the OR circuit 596 is It is output from the circuit 590 and input to the control circuit 500 .

[0139] As described above, in the timing control circuit 590 of this embodiment, the D-type flip-flop 592 is input to the data input terminal D1 at the rising edge of the clock signal CK. When the comparison result signal Vcr is at H level, the data signal Do1 at H level is outputted, and the clock The comparison result signal V input to the data input terminal D1 at the rising edge of the clock signal CK When cr is at L level, the data signal Do1 is output at L level. The flip-flop 594 receives the data input to the data input terminal D2 at the falling edge of the clock signal CK. When the input comparison result signal Vcr is at H level, the H-level data signal Do2 is The ratio of the data input to the data input terminal D2 at the falling edge of the clock signal CK is When the comparison result signal Vcr is at L level, the data signal Do2 at L level is output.

[0140] Therefore, the OR circuit 596 outputs the clock signal CK at the rising edge of the clock signal CK. The control circuit 590 receives the comparison result signal Vcr at L level, and immediately after that, the clock signal CK At the falling edge, the comparison result signal Vcr of L level is input to the timing control circuit 590. or when the timing control circuit The comparison result signal Vcr at the L level is input to the circuit 590, and immediately after that, the rising edge of the clock signal CK In this case, the comparison result signal Vcr of L level is input to the timing control circuit 590. If the timing control signal Tgi is low, the timing control signal Tgi is generated and output. The clock control circuit 590 detects the rising edge and the falling edge of the clock signal CK. When both of the comparison result signals Vcr are at the L level, the timing control circuit 5 90 indicates the period from the falling edge to the rising edge of the clock signal CK or The comparison result signal is at L level continuously during the period from the rising edge to the falling edge of the clock signal CK. It determines that Vcr is being input, and outputs the L-level timing control signal Tgi.

[0141] As described above, the timing control circuit 590 of this embodiment receives the comparison result signal Vcr. D-type flip-flop 592 and D-type flip-flop 594 are connected to each other. The data signal Do1 output by the D-type flip-flop 592 and the data signal Do2 output by the D-type flip-flop 594 are and an OR circuit 596 to which the data signal Do2 is input. 2 is a signal corresponding to the logic level of the comparison result signal Vcr at the rising edge of the clock signal CK. The data signal Do1 is output, and the D-type flip-flop 594 is set to the falling edge of the clock signal CK. A data signal Do2 is output according to the logic level of the comparison result signal Vcr at the The circuit 596 operates in response to the logic level of the data signal Do1 and the logic level of the data signal Do2. The timing control signal Tgi is output.

[0142] Returning to FIG. 14, the control circuit 500 receives the temperature acquisition request signal T In response to D, the select signal Sel and the clock signal CK are output, and the control circuit 1 00 and the temperature acquisition request signal TD input from the timing control circuit 590. The enable signals EN1 and EN2 are output in response to the timing control signal Tgi. Thus, the control circuit 500 controls the operations of the various components included in the temperature information output circuit 26. The control circuit 500 also acquires the input digital temperature information dtc and converts the acquired digital The control circuit 500 generates a temperature information signal TI according to the temperature information dtc. The temperature information signal TI thus generated is output from the temperature information output circuit 26. It is input to the control circuit 100.

[0143] Specifically, the control circuit 500 includes a request analysis unit 501, a clock signal output unit 502, a temperature It includes an information output unit 503 , a correction value calculation unit 504 , and a memory control unit 505 .

[0144] When the request analysis unit 501 receives a temperature acquisition request signal TD input to the control circuit 500, The control circuit 500 analyzes both the select signal and the request signal in accordance with the analysis result of the request analysis unit 501. The signal Sel is generated and output to the multiplexer 510. 510 is a head temperature signal TC selected by the select signal Sel, The head temperature signal TC designated by the acquisition request signal TD is selected. The circuit 520 amplifies the head temperature signal TC designated by the temperature acquisition request signal TD. A width head temperature signal ATC is generated and output to an A / D converter 530 .

[0145] The clock signal output unit 502 divides or multiplies the frequency of an oscillation signal output by an oscillation circuit (not shown). The control circuit 500 generates the clock signal C. At this time, the clock signal output unit 502 outputs the temperature Whether or not to generate a clock signal CK is controlled according to the analysis result of the acquisition request signal TD. The cycle and frequency of the generated clock signal CK may be controlled. The lock signal output unit 502 receives the analysis result of the temperature acquisition request signal TD from the request analysis unit 501. A clock signal CK having a predetermined cycle and frequency may be generated regardless of the clock frequency.

[0146] The temperature information output unit 503 outputs a temperature acquisition request signal requesting acquisition of the temperature of the print head 22. The timing control signal Tgi is determined after the signal TD is input to the control circuit 500. In this embodiment, the timing is the time when the temperature of the print head 22 is requested to be acquired. After the acquisition request signal TD is input to the control circuit 500, the logic level of the timing control signal Tgi When the bell goes low, the operation of the A / D converter 530 is enabled. This causes the A / D converter 530 to output an enable signal EN1 that controls the , the amplified head temperature signal ATC output by the amplifier circuit 520 is acquired, and a digital signal and outputs it to the control circuit 500 as digital temperature information dtc. The information output unit 503 acquires the digital temperature information dtc output by the A / D converter 530. The control circuit 5 generates a temperature information signal TI based on the acquired digital temperature information dtc. 00 transmits the temperature information signal TI generated by the temperature information output unit 503 to the control circuit 100 Output to.

[0147] That is, the temperature information output unit 503 detects when the logic level of the timing control signal Tgi is at the L level. At the timing when the temperature reaches a certain value, the voltage of the head temperature signal TC output by the print head 22 is A temperature information signal TI based on digital temperature information dtc according to the pressure value, The temperature of the print head 22 corresponding to the head temperature signal TC specified by the signal TD is The control circuit 500 generates a temperature information signal TI in response to the temperature information output unit 503. The temperature information signal TI generated by the temperature sensor 102 is output to the control circuit 100.

[0148] The correction value calculation unit 504 calculates a correction value for correcting the temperature information signal TI output by the control circuit 500. The correction value calculation unit 504 calculates the correction value Cv, for example, by receiving the correction value Cv from the control circuit 100. At a predetermined timing after the temperature acquisition request signal TD including the request is input, the A / D converter The enable signal EN1 controls the operation of the inverter 530, and the A / D converter 560 and outputs an enable signal EN2 that effectively controls the operation of A / The D converter 530 acquires the amplified head temperature signal ATC output by the amplifier circuit 520. and converts it into a digital signal, outputs it as digital temperature information dtc, and The / D converter 560 receives the amplification unit temperature signal ATH output by the amplifier circuit 550. The temperature sensor 100 converts the temperature data into a digital signal and outputs it as digital temperature information dth. The correction value calculation unit 504 calculates the digital temperature information dtc and the digital temperature information dth and based on the acquired digital temperature information dtc and digital temperature information dth, A correction value Cv is calculated.

[0149] Specifically, the control circuit 500 receives a correction signal corresponding to the print head 22 from the control circuit 100. When a temperature acquisition request signal TD including a request to calculate a positive value Cv is input, the request analysis unit 501 , a select signal Sel is output to select the corresponding print head 22. The value calculation unit 504 outputs an enable signal E that effectively controls the operation of the A / D converter 530. N1 and an enable signal EN2 that effectively controls the operation of the A / D converter 560. As a result, the correction value calculation unit 504 outputs the digital signals at the same timing. The correction value calculation unit 504 acquires the temperature information dtc and the digital temperature information dth. Based on the difference between the digital temperature information dtc and the digital temperature information dth, At this time, the correction value calculation unit 504 calculates a correction value Cv corresponding to the print head 22. The n correction values ​​Cv corresponding to the heads 22-1 to 22-n may be calculated individually. The temperature information output unit 503 uses the correction value Cv calculated by the correction value calculation unit 504 to obtain The digital temperature information DTC is corrected, and the temperature information based on the corrected digital temperature information DTC is As a result, the accuracy of the temperature information signal TI output by the control circuit 500 is improved. will improve.

[0150] The memory control unit 505 outputs a memory control signal MA for accessing the memory circuit 570. and outputs it to the memory circuit 570, and also outputs it to the memory circuit 570 in response to the memory control signal MA. Specifically, the memory circuit 570 includes: Various information including the n correction values ​​Cv described above is stored in the memory control unit 505. A memory control signal MA for storing information such as the correction value Cv is generated and stored in the memory circuit 570. In addition to outputting the signal, the correction value Cv and other information stored in the memory circuit 570 are read out. The memory control signal MA is generated and output to the memory circuit 570.

[0151] The memory circuit 570 stores various values ​​including the correction value Cv in response to the input memory control signal MA. The information is stored, and the information such as the correction value Cv is read out, and the memory containing the read information is The memory circuit 570 outputs a read signal MR to the control circuit 500. It is configured to include non-volatile memory such as flash memory.

[0152] As described above, the temperature information output circuit 26 detects the temperature of the print head 22 from the head temperature signal TC. A control circuit 500 that acquires digital temperature information dtc according to temperature, a timing control circuit 590 for controlling the timing of acquiring the digital temperature information DTC; Such a temperature information output circuit 26 may be configured as an integrated circuit, for example. This is preferable. As a result, the head unit 20 can be made smaller. In this case, the integrated circuit that constitutes the temperature information output circuit 26 is not limited to one. Of course, the temperature information output circuit 26 may be provided with a plurality of integrated circuits in addition to the integrated circuit. The circuit element may be configured to include the above.

[0153] 7.Temperature detection timing in the temperature information output circuit In the liquid ejection device 1 and the head unit 20, ink is ejected from the nozzle 321. The physical properties of ink, such as viscosity, change depending on the temperature. This contributes greatly to the ejection accuracy. The temperature of the ink discharged from the nozzle 321 is the temperature of the pressure chamber 312 The temperature of the ink stored in the liquid ejection device 1 is acquired, and the temperature of the ink stored in the liquid ejection device 1 is acquired. By correcting the various signals that control the operation of the head unit 20, the ink temperature can be adjusted Even in this case, the risk of ink ejection accuracy being reduced is reduced.

[0154] In particular, in the liquid ejection device 1 and the head unit 20 of this embodiment, the print head 22 The temperature detection circuit 250 detects the temperature of the resistor wiring 401 whose resistance value changes depending on the temperature. The resistive wiring 401 is located in the vicinity of the pressure chamber 312, and the pressure chamber 312 is formed The force chamber substrate 310 is formed on a diaphragm 350 that seals the opening on the +Z side surface. The temperature detection circuit 250 detects the temperature of the ink stored in the pressure chamber 312 by detecting the temperature of the ink stored in the pressure chamber 312. This makes it possible to detect the temperature of the ink stored in the pressure chamber 312 more accurately. As a result, the liquid ejection device 1 and the head unit according to this embodiment can be effectively detected. In 20, the liquid ejection device 1 and the head 21 are controlled in accordance with the temperature of the ink stored in the pressure chamber 312. This makes it possible to more appropriately correct the various signals that control the operation of the ink unit 20. Even if the temperature of the ink changes, the ink ejection accuracy is further reduced. It is possible.

[0155] On the other hand, the resistance wiring 401 included in the temperature detection circuit 250 is connected to the pressure chamber in which the ink is stored. 312, the following problems may occur significantly.

[0156] In order to improve the quality of the image formed on the medium P, the print head 22 is provided with several hundred or more The nozzles 321 are arranged at high density. The piezoelectric element 60 has several hundred or more corresponding to several hundred or more nozzles 321, 0 or more piezoelectric elements 60 are arranged at high density on the diaphragm 350. Signal wiring through which the drive signal VOUT supplied to each piezoelectric element 60 in the head 22 propagates. are arranged densely on the diaphragm 350. When the resistive wiring 401 is arranged, the resistive wiring 4 is arranged near the signal wiring through which the drive signal VOUT propagates. 01 is placed, and the noise generated by the change in the voltage value of the drive signal VOUT is If the voltage of the drive signal VOUT changes, If the noise generated as a result of the resistance wiring 401 is contributed to by the resistance wiring 401, the temperature detection circuit including the resistance wiring 401 The accuracy of the head temperature signal TC output by the pressure chamber 312 is reduced. Decreases.

[0157] When the piezoelectric element 60 is driven by the drive signal VOUT, the drive As a result, the vibration plate 350 on which the resistance wiring 401 is arranged is displaced. Accordingly, the impedance of the resistive wiring 401 arranged on the diaphragm 350 may change. If the impedance of the resistive wiring 401 arranged on the diaphragm 350 changes, In this case, the accuracy of the head temperature signal TC output by the temperature detection circuit 250 including the resistance wiring 401 is The temperature of the pressure chamber 312 decreases, and the accuracy of detecting the temperature of the pressure chamber 312 decreases.

[0158] Furthermore, as described above, the print head 22 changes the pressure by changing the volume of the pressure chamber 312. Pressure is applied to the ink contained in the pressure chamber 312, causing the ink to be ejected from the nozzle 321. In the print head 22 having such a structure, the pressure chamber 312 that is generated when ink is ejected The temperature of the ink stored in the pressure chamber 312 may change instantaneously due to the pressure change. The instantaneous temperature change is detected by a temperature detection circuit including the resistance wiring 401. 250 detects the temperature of the head, and the temperature signal TC output by the temperature detection circuit 250 contains noise. If the ink stored in the pressure chamber 312 has a temperature When a temperature change is superimposed on the head temperature signal TC as noise, the temperature detection circuit 250 The accuracy of the output head temperature signal TC decreases, and the accuracy of detecting the temperature of the pressure chamber 312 decreases. .

[0159] To address this problem, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 has The timing control circuit 590 controls the optimum timing for acquiring the head temperature signal TC. The digital temperature information dtc based on the head temperature signal TC acquired by the control circuit 500 is The accuracy is improved and the reliability of the temperature information signal TI based on the digital temperature information dtc is improved. This reduces the accuracy of detecting the temperature of the pressure chamber 312 detected by the temperature detection circuit 250. This reduces the risk of this happening.

[0160] To explain the timing for acquiring the temperature of the print head 22, first, An example of the operation of the liquid ejection device 1 of the embodiment will be described, and then the operation of the liquid ejection device 1 will be described. An example of the timing for acquiring the temperature of the print head 22 in this example will be described. 5A to 5C are diagrams illustrating an example of the operation of the liquid ejection device 1 according to the embodiment.

[0161] As described above, the liquid ejection device 1 of this embodiment is a serial printing type inkjet printer. The carriage reciprocating along the scanning direction immediately before time t10 is At this time, the control circuit 100 A control signal Ctrl-C is sent to stop the carriage 21 carrying the print head 22. The scanning direction of the carriage 21 is reversed, and the driving circuit The reference numeral 50 outputs a drive signal COM whose voltage value is constant at voltage Vb.

[0162] Then, at time t10, when the reversal process of the scanning direction of the carriage 21 is completed, The drive circuit 50 starts outputting the drive signal COM whose voltage value is constant at the voltage Vc. Time t10 when the drive circuit 50 starts outputting the drive signal COM with a constant voltage Vc In order to control all the selection circuits 230 to be conductive, the control circuit 100 outputs the selection signal The print data signal SI is output to control the logic level of S to H level. The electrodes 360 of the plurality of piezoelectric elements 60 of the print head 22 are connected to the drive circuit 50. The drive signal VOUT is based on the drive signal COM output by the A drive signal VOUT that varies rapidly is provided.

[0163] After that, the voltage value of the drive signal COM output by the drive circuit 50 becomes constant at voltage Vc. A drive signal VOUT having a voltage value of Vc is supplied to the electrode 360 ​​of the piezoelectric element 60. Then, the control circuit 100 applies a drive signal having a voltage value of Vc to the electrode 360 ​​of the piezoelectric element 60. After VOUT is supplied, the selection signal S The print data signal SI is output to control the logic level of the selection circuit to the L level. At this time, the voltage value of the electrode 360 ​​of the piezoelectric element 60 is The capacitance of element 60 holds the voltage Vc.

[0164] Then, after the voltage value of the drive signal COM output by the drive circuit 50 becomes constant at voltage Vc, At time t20, the control circuit 100 controls the carriage 2 carrying the print head 22. 1 is moved in the forward direction Fw from the home position side to the opposite side of the home position. This outputs a control signal Ctrl-C to move the carriage 21 along the scanning axis. Then, the movement in the forward direction Fw starts.

[0165] At time t30 after the carriage 21 starts moving in the forward direction Fw along the scanning axis, The driving circuit 50 generates a driving signal in which trapezoidal waveforms Adp, Bdp, and Cdp are successively generated as shown in FIG. Then, at a time t40, the carriage 21 starts to output the signal COM. When the scanning position reaches the printing area where an image is formed on the medium P, the control circuit 100 A print data signal SI and a clock signal SCK corresponding to an image information signal input from an external device and outputs a change signal CH and a latch signal LAT according to the scanning position of the carriage 21. Therefore, the selection control circuit 210 outputs the signals corresponding to the plurality of piezoelectric elements 60. The selection circuit 230 outputs a selection signal S of a logic level, and the selection circuit 230 outputs a drive signal COM based on the drive signal COM. VOUT is output. As a result, an image corresponding to the image information signal is formed on the medium P. That is, a printing process is performed in which ink is ejected onto the medium P. Here, the printing area is the area The ink ejection head 22 is capable of ejecting ink onto the medium P. At least a portion of the print head 22 is positioned facing the medium P along the ejection direction. The area includes:

[0166] At time t50, when the printing process in the forward direction Fw along the scanning axis is completed, the control The circuit 100 controls all the selection circuits 230 to be non-conductive by changing the logic level of the selection signal S. The selection circuit 230 outputs a print data signal SI that controls the filter to the L level. At this time, the voltage value of the electrode 360 ​​of the piezoelectric element 60 is The voltage Vc is maintained by the capacitance component. At a later time t60, the drive circuit 50 , trapezoidal waveforms Adp, Bdp, Cdp stop outputting the drive signal COM, and the voltage value Start outputting a constant drive signal COM at voltage Vc.

[0167] Then, after the voltage value of the drive signal COM output by the drive circuit 50 becomes constant at voltage Vc, At time t70, the scanning position of the carriage 21 reaches the stop area on the opposite side to the home position. When it reaches the target position, the control circuit 100 stops the carriage 21 carrying the print head 22. The control signal Ctrl-C is output to stop the carriage 21.

[0168] At time t80 after the carriage 21 has stopped, the drive circuit 50 changes its voltage value to voltage V b, the drive circuit 50 starts outputting a constant drive signal COM. At time t80 when the constant drive signal COM starts to be output, the control circuit 100 In order to control the selection circuit 230 to be conductive, the logic level of the selection signal S is controlled to be H level. As a result, the print head 22 outputs a print data signal SI corresponding to the plurality of piezoelectric elements. The electrodes 360 of the elements 60 are connected to the driving circuits 50 in response to the driving signals COM. A drive signal VOUT whose voltage value changes toward voltage Vb is supplied. will be done.

[0169] The voltage value of the drive signal VOUT supplied to the electrode 360 ​​of the piezoelectric element 60 is constant at voltage Vb. After this, the control circuit 100 turns off the selection signal . The print data signal SI is output to control the logic level of the selected signal S to the L level. At this time, the voltage value of the electrode 360 ​​of the piezoelectric element 60 is The voltage Vb is maintained by the capacitance component of the piezoelectric element 60. After that, the liquid ejection device 1 The driving circuit 50 continues to output the driving signal COM with a constant voltage Vb. The scanning direction of the ridge 21 is the reverse direction R from the opposite side to the home position side. Wait a period until the inversion process is complete.

[0170] Also, at a predetermined time during the waiting period until the reversal process of the scanning direction of the carriage 21 is completed, In this timing, the drive circuit 50 outputs a drive signal COM including a micro-vibration waveform obs. At this time, the control circuit 100 controls all the selection circuits 230 to be conductive. The print data signal SI is output to control the logic level of the pressure signal S to a high level. A drive signal VOUT including a micro-vibration waveform obs is supplied to the electrode 360 ​​of the capacitor 60. As a result, the risk of ink sticking to the vicinity of the nozzle 321 during the standby period is reduced. In addition, the possibility of the ink viscosity increasing in the vicinity of the nozzle 321 is reduced. The drive signal VOUT including bs is supplied to all the piezoelectric elements 60 of the print head 22. The present invention is not limited to the case where only some of the piezoelectric elements 60 of the print head 22 are used. The micro-vibration caused by the drive signal VOUT including the micro-vibration waveform obs may be It may be executed multiple times during the waiting period.

[0171] At time t90, when the reversal process of the scanning direction of the carriage 21 is completed, the drive circuit 5 0 starts outputting the drive signal COM whose voltage value is constant at voltage Vc. At time t90, the voltage Vc of the drive signal COM is constant. , the control circuit 100 controls all the selection circuits 230 to be conductive by changing the logic level of the selection signal S. This outputs a print data signal SI that controls the level to H level. The electrodes 360 of the plurality of piezoelectric elements 60 of the electrode 22 are connected to the electrodes 360. The drive signal VOUT is based on the drive signal COM, and the voltage value changes toward the voltage Vc. A drive signal VOUT is supplied.

[0172] After that, the voltage value of the drive signal COM output by the drive circuit 50 becomes constant at voltage Vc. A drive signal VOUT having a voltage value of Vc is supplied to the electrode 360 ​​of the piezoelectric element 60. Then, the control circuit 100 applies a drive signal having a voltage value of Vc to the electrode 360 ​​of the piezoelectric element 60. After VOUT is supplied, the selection signal S The print data signal SI is output to control the logic level of the selection circuit to the L level. At this time, the voltage value of the electrode 360 ​​of the piezoelectric element 60 is The capacitance of element 60 holds the voltage Vc.

[0173] Then, after the voltage value of the drive signal COM output by the drive circuit 50 becomes constant at voltage Vc, At time t100, the control circuit 100 controls the carriage carrying the print head 22. Move 21 along the reverse direction Rv from the opposite side to the home position side This outputs a control signal Ctrl-C to move the carriage 21 along the scanning axis. Then, movement in the opposite direction Rv along the axis begins.

[0174] At time t110 after the carriage 21 starts moving in the reverse direction Rv along the scanning axis, The drive circuit 50 outputs a drive signal COM having successive trapezoidal waveforms Adp, Bdp, and Cdp. Then, at a subsequent time t120, the scanning position of the carriage 21 is When the medium P reaches the printing area where an image is to be formed, the control circuit 100 receives the input from the external device. A print data signal SI and a clock signal SCK corresponding to the input image information signal, and a carrier The change signal CH and latch signal LAT are output in accordance with the scanning position of the image sensor 21. As a result, the selection control circuit 210 outputs a logic level signal corresponding to each of the plurality of piezoelectric elements 60. The selection circuit 230 outputs a selection signal S, and the selection circuit 230 outputs a drive signal VOUT based on the drive signal COM. As a result, an image corresponding to the image information signal is formed on the medium P. The process is executed.

[0175] At time t130, when the printing process in the reverse direction Rv along the scanning axis is completed, the control The control circuit 100 controls all the selection circuits 230 to be non-conductive by setting the logic level of the selection signal S. The selection circuit 230 outputs a print data signal SI that controls the level of the selection circuit 230 to L level. At this time, the voltage value of the electrode 360 ​​of the piezoelectric element 60 is controlled to be non-conductive. At a subsequent time t140, the drive circuit 5 0 stops the output of the drive signal COM, which is a series of trapezoidal waveforms Adp, Bdp, and Cdp, and The output of the drive signal COM, whose value is constant at voltage Vc, begins.

[0176] Then, after the voltage value of the drive signal COM output by the drive circuit 50 becomes constant at voltage Vc, At time t150, the scanning position of the carriage 21 reaches the stop area on the home position side. When it reaches the target position, the control circuit 100 stops the carriage 21 carrying the print head 22. The control signal Ctrl-C is output to stop the carriage 21.

[0177] At time t160 after the carriage 21 stops, the drive circuit 50 detects that the voltage value is The drive circuit 50 starts outputting a constant drive signal COM at Vb. At time t160 when the output of the constant drive signal COM is started at b, the control circuit 100 In order to control all the selection circuits 230 to be conductive, the logic level of the selection signal S is controlled to the H level. As a result, the print head 22 outputs a print data signal SI that controls the The electrodes 360 of the piezoelectric element 60 are driven based on the drive signal COM output from the drive circuit 50. The drive signal VOUT is based on the voltage Vb. Supplied.

[0178] The voltage value of the drive signal VOUT supplied to the electrode 360 ​​of the piezoelectric element 60 is constant at voltage Vb. After this, the control circuit 100 turns off the selection signal . The print data signal SI is output to control the logic level of the selected signal S to the L level. At this time, the voltage value of the electrode 360 ​​of the piezoelectric element 60 is The voltage Vb is maintained by the capacitance component of the piezoelectric element 60. After that, the liquid ejection device 1 The driving circuit 50 continues to output the driving signal COM with a constant voltage Vb. The scanning direction of the ridge 21 is set to the forward direction Fw from the home position to the anti-home position. The inversion process waits for a period of time until the inversion process is completed.

[0179] Also, at a predetermined time during the waiting period until the reversal process of the scanning direction of the carriage 21 is completed, In this timing, the drive circuit 50 outputs a drive signal COM including a micro-vibration waveform obs. At this time, the control circuit 100 controls all the selection circuits 230 to be conductive. The print data signal SI is output to control the logic level of the pressure signal S to a high level. A drive signal VOUT including a micro-vibration waveform obs is supplied to the electrode 360 ​​of the capacitor 60. As a result, the risk of ink sticking to the vicinity of the nozzle 321 during the standby period is reduced. In addition, the possibility of the ink viscosity increasing in the vicinity of the nozzle 321 is reduced. The drive signal VOUT including bs is supplied to all the piezoelectric elements 60 of the print head 22. The present invention is not limited to the case where only some of the piezoelectric elements 60 of the print head 22 are used. The micro-vibration caused by the drive signal VOUT including the micro-vibration waveform obs may be It may be executed multiple times during the waiting period.

[0180] At a subsequent time t170, when the process of reversing the scanning direction of the carriage 21 is completed, The drive circuit 50 starts outputting a signal whose voltage value is constant at voltage Vc as the drive signal COM. That is, the same operation as that at time t10 described above is started. The liquid ejection device 1 repeatedly executes the above-described operation from time t10 to time t160. In both cases, the medium P is conveyed in the conveying direction, and an image corresponding to the image information signal is printed on the medium P. Form into.

[0181] In the liquid ejection device 1 of this embodiment that operates as described above, the temperature information output circuit 26 During the period in which the drive circuit 50 outputs the drive signal COM with a constant voltage value, the piezoelectric element During the period when the drive signal VOUT whose voltage value fluctuates is not supplied to the element 60, Acquires and obtains digital temperature information DTC based on the head temperature signal TC according to the temperature of 22 Based on the digital temperature information dtc, a temperature corresponding to the temperature of the corresponding print head 22 is calculated. The temperature information output circuit 26 generates a temperature information signal TI and outputs it to the control circuit 100. is a period during which the drive signal VOUT, whose voltage value changes, is not supplied to the piezoelectric element 60. Therefore, the piezoelectric element 60 is not driven by the drive signal VOUT, and therefore the diaphragm 350 is not displaced. During this period, the digital signal based on the head temperature signal TC corresponding to the temperature of the print head 22 is acquired. The temperature information signal TI is generated according to the temperature information dtc and output to the control circuit 100.

[0182] As a result, the head temperature signal TC acquired by the temperature information output circuit 26 is The propagation of T, the displacement of the vibration plate 350, and the instantaneous temperature of the ink stored in the pressure chamber 312 As a result, the temperature information output circuit 2 The accuracy of the head temperature signal TC acquired by the head temperature sensor 6 is the accuracy of the detection of the temperature of the pressure chamber 312. This improves the reliability of the temperature information signal TI output by the temperature information output circuit 26.

[0183] Specifically, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 is 15, the temperature information output circuit 26 receives the drive signal V OUT is not supplied to the piezoelectric element 60, and the piezoelectric element 60 is driven by the drive signal VOUT. The detection period shown in FIG. 16 is a period in which the element 60 is not driven and therefore the diaphragm 350 is not displaced. During the period Tdet, a data signal based on the head temperature signal TC corresponding to the temperature of the print head 22 is Digital temperature information DTC is acquired, and a temperature information signal corresponding to the acquired digital temperature information DTC is generated. Outputs TI.

[0184] Figure 17 shows the temperature information when acquiring the digital temperature information dtc during the detection period Tdet. 17 is a diagram illustrating an example of the operation of the output circuit 26. Note that time t80 shown in FIG. 17, the comparison circuit 580 indicates the same time as time t80 shown in FIG. Outputs the level comparison result signal Vcr, or the L level comparison result signal Vcr. The voltage value of the switching voltage Vch that switches between the period when printing is being performed is The start timing and The voltage Vc is the voltage value at the start and end timing of the detection period Tdet, and the drive signal COM The voltage Vb output as a comparison circuit is set to a value between Vb and Vc. The resistance values ​​of the resistors 584 and 586 in the circuit 580 are set so that the voltage value of the switching voltage Vch is equal to the voltage Vc The voltage is set to a value between Vb and Vc. The half period of the period Pck of the clock signal CK output by the circuit 500 is The voltage value of the signal COM starts decreasing from voltage Vc and reaches voltage Vb in the period Δt. It is set to be long.

[0185] As shown in FIG. 17, immediately before time t80, the drive circuit 50 detects a voltage Vc Therefore, just before time t80, the constant drive signal COM is output. The circuit 580 outputs the comparison result signal Vcr at the H level. Just before that, the data input terminal D1 of the D-type flip-flop 592 and The comparison result signal Vcr of H level is input to the data input terminal D2 of the flip-chip 594. Therefore, just before time t80, D-type flip-flop 592 outputs a high level de- D-type flip-flop 594 outputs a high-level data signal Do2. Therefore, immediately before time t80, the timing control circuit 590 The timing control signal Tgi of H level is output to the control circuit 500. 500 is input with the timing control signal Tgi at H level, so the A / D converter Therefore, the enable signal EN1 that enables the operation of the A / D The converter 530 does not output digital temperature information dtc in response to the head temperature signal TC. Therefore, the control circuit 500 does not generate the temperature information signal TI according to the digital temperature information dtc.

[0186] At a subsequent time t80, when the movement of the carriage 21 stops, the drive circuit 50 The drive circuit 50 starts outputting the drive signal COM whose voltage value is constant at voltage Vb. The voltage value of the output drive signal COM decreases from voltage Vc to voltage Vb. At time t81 when the voltage value of the drive signal COM output from the drive circuit 50 falls below the switching voltage Vch, In this case, the logic level of the comparison result signal Vcr output by the comparison circuit 580 changes from the H level to the L level. That is, at time t81, the data of the D-type flip-flop 592 is switched to The data input terminal D1 of the D-type flip-flop 594 and the data input terminal D2 of the D-type flip-flop 595 are set to the L level. The comparison result signal Vcr is input.

[0187] Then, after time t81, at time t82 when the clock signal CK rises, the D-type flash The flip-flop 592 receives the comparison result signal Vc at the L level input to the data input terminal D1. After time t81, the clock signal CK is At the falling time t83, the D-type flip-flop 594 has a data input terminal D2 A low-level data signal Do2 is output in response to the low-level comparison result signal Vcr that is input. Therefore, at time t83, the OR circuit 596 receives the L-level data signal Do 1 and the L-level data signal Do2 are input. As a result, the OR circuit 596 outputs L The timing control circuit 590 generates a timing control signal Tgi of L level. The timing control signal Tgi is output to the control circuit 500 .

[0188] When the timing control signal Tgi of L level is input, the control circuit 500 It outputs an enable signal EN1 that enables the operation of the converter 530. When an enable signal EN1 that enables the operation is input, the motor 530 controls the head temperature. The control circuit 500 outputs digital temperature information dtc corresponding to the temperature signal TC. The control circuit 500 then acquires the digital temperature information dtc output by the temperature sensor 530. Then, a temperature information signal TI is generated according to the acquired digital temperature information dtc. The temperature information output circuit 26 outputs a head temperature signal TC corresponding to the temperature of the print head 22. The digital temperature information dtc is acquired, and the temperature information signal corresponding to the acquired digital temperature information dtc is output. The signal TI is output to the control circuit 100.

[0189] At this time, half the period Pck of the clock signal CK output by the control circuit 500 is Set longer than the period Δt until the voltage value of the signal COM decreases from voltage Vc to voltage Vb Therefore, the timing control circuit 590 outputs the L-level timing control signal Tgi to the control circuit 500, and the control circuit 500 outputs the digital temperature information At time t83 when dtc is acquired, the voltage value of the drive signal COM output by the drive circuit 50 Therefore, the driving signal VOU whose voltage value fluctuates is applied to the piezoelectric element 60. Therefore, at time t83, the temperature information output circuit 26 acquires The head temperature signal TC is transmitted by the propagation of the drive signal VOUT, the displacement of the diaphragm 350, and the pressure chamber 3 There is a risk of noise being superimposed due to instantaneous temperature changes in the ink stored in 12. As a result, the accuracy of the head temperature signal TC acquired by the temperature information output circuit 26 is reduced. This improves the accuracy of detecting the temperature of the pressure chamber 312, and the temperature information output circuit 26 outputs This improves the reliability of the temperature information signal TI.

[0190] As described above, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 The timing control circuit 590 determines whether the voltage value of the drive signal COM is constant or not, and Based on the result, the control circuit 500 controls the timing for acquiring the digital temperature information dtc. Specifically, the timing control circuit 590 of this embodiment controls the voltage value of the drive signal COM. If the voltage value of the drive signal COM is below the switching voltage Vch for a predetermined time, it is determined that the voltage value of the drive signal COM is constant. The control circuit 500 determines the timing control signal Tgi at a low level and outputs the timing control signal Tgi at a low level. The temperature information dtc is acquired by controlling the period Pck of the clock signal CK. The time period equal to or longer than half the period of the temperature information corresponds to the predetermined time period in this embodiment. The output circuit 26 does not have a complicated configuration, and the head temperature information acquired by the temperature information output circuit 26 is The degree signal TC is generated by the propagation of the drive signal VOUT, the displacement of the diaphragm 350, and the pressure stored in the pressure chamber 312. This reduces the possibility of noise and the like being superimposed due to an instantaneous change in the ink temperature. As a result, the accuracy of the head temperature signal TC acquired by the temperature information output circuit 26 is The accuracy of detecting the temperature of the pressure chamber 312 is improved, and the temperature information signal output by the temperature information output circuit 26 This improves the reliability of the TI.

[0191] In FIG. 17, the clock signal CK rises at time t82 and The explanation has been given assuming that the clock signal CK falls at time t82. Alternatively, the clock signal CK may fall at time t81, and the clock signal CK may rise at time t82. In this case, at time t82 when the clock signal CK falls, the D-type flip-flop 5 94 is an L level output corresponding to the L level comparison result signal Vcr input to the data input terminal D2. At time t83 when the clock signal CK rises, The flip-flop 592 receives the comparison result signal of L level input to the data input terminal D1. A data signal Do1 of L level according to Vcr is output, and thereafter, the operation shown in FIG. 17 is executed. can be.

[0192] On the other hand, the voltage amplitude of the drive signal COM, which has successive trapezoidal waveforms Adp, Bdp, and Cdp, is It changes depending on the amount of ink ejected and the viscosity. Therefore, trapezoidal waveforms Adp, Bdp, The minimum voltage value of the drive signal COM where Cdp is continuous may fall below the switching voltage Vch. If the minimum voltage value of the drive signal COM where the trapezoidal waveforms Adp, Bdp, and Cdp are successive is the switching voltage, When the voltage V falls below Vch, the temperature information output circuit 26 detects that the voltage value of the drive signal COM is constant. The digital temperature based on the head temperature signal TC in the temperature information output circuit 26 is erroneously determined. There is a risk that the accuracy of obtaining information dtc will decrease.

[0193] To address this problem, the liquid ejection device 1 of this embodiment uses a D-type flip-flop 592, 594 by optimally setting the cycle of the clock signal CK that acquires the comparison result signal Vcr. The drive circuit 50 outputs a drive signal COM having successive trapezoidal waveforms Adp, Bdp, and Cdp. During this period, the temperature information output circuit 26 erroneously determines that the voltage value of the drive signal COM is constant. The temperature information output circuit 26 outputs a digital signal based on the head temperature signal TC. This reduces the risk of a decrease in the accuracy of obtaining the temperature information DTC.

[0194] FIG. 18 shows a drive signal COM in which the drive circuit 50 generates a series of trapezoidal waveforms Adp, Bdp, and Cdp. For example, the period from time t30 to time t60 shown in FIG. 10 is a diagram showing an example of the operation of the temperature information output circuit 26 in a part of the period.

[0195] In Figure 18, the voltage value of the drive signal COM, which has successive trapezoidal waveforms Adp, Bdp, and Cdp, is switched. The periods Ph1, Ph2, and Ph3 exceeding the switching voltage Vch, and the trapezoidal waveforms Adp, Bdp, and Cdp The periods P11 and P12 in which the voltage value of the drive signal COM is lower than the switching voltage Vch are also included. Here, the period Ph1 shown in FIG. 18 is the same as the period Ph3 in the immediately preceding cycle tp. Therefore, the periods Ph1 and Ph3 are considered to be one continuous period. In the following description, the period Ph1 and the period Ph3 are consecutively referred to as the period Ph4. It is called.

[0196] As described above, the temperature information output circuit 26 receives the rising and falling edges of the clock signal CK. As a result, the comparison result signal Vcr of the L level is input successively, and the drive signal COM Therefore, the drive circuit 50 generates trapezoidal waveforms Adp, Bdp, C During the period when dp outputs a continuous drive signal COM, When the comparison result signal Vcr is input at the L level consecutively at the rising and falling edges, The temperature information output circuit 26 erroneously determines that the voltage value of the drive signal COM is constant.

[0197] Therefore, in the liquid ejection device 1 of this embodiment, as shown in FIG. 18, the control circuit 500 The rising and falling edges of the clock signal CK are consecutive and are included in the periods P11 and P12. Specifically, the control circuit 500 controls the period Pck of the clock signal CK so that the period Pck is not exceeded. The half period Pck of the clock signal CK is longer than both of the periods Pl1 and Pl2. In other words, the period Pck of the clock signal CK is controlled so that In a period tp, which is one period of the drive signal COM, the comparison circuit 580 The control circuit is set to a value longer than the maximum value of the time for which the L-level comparison result signal Vcr is output. 500 controls the frequency of the clock signal CK.

[0198] As a result, the rising and falling edges of the clock signal CK are consecutively set in the period P11 or As a result, the risk of the drive circuit 50 generating the trapezoidal waveforms Adp,B During the period when the drive signal COM is output in succession, the temperature information output circuit 26 However, the possibility of determining that the voltage value of the drive signal COM is constant is reduced.

[0199] Furthermore, in the liquid ejection device 1 of this embodiment, as shown in FIG. 18, In a period tp, the length of which is one half period of the drive signal COM, the comparator circuit 580 outputs a high The control circuit 5 is configured to output the level comparison result signal Vcr in a time shorter than the minimum value. 00 controls the frequency of the clock signal CK.

[0200] As a result, in each of the periods Ph2 and Ph4, the rising edge of the clock signal CK Therefore, if the clock When the rising edge of the clock signal CK occurs in either the period P11 or the period P12, The falling edge of the clock signal CK following the rising edge occurs in periods Ph2 and Ph4. Similarly, the falling edge of the clock signal CK cannot occur during the other of the periods P11 and P12. If the falling edge occurs during the period P11 or P12, the clock signal C The rise of K occurs in periods Ph2 and Ph4, and the rise of K occurs in periods P11 or P12. Therefore, if the rising and falling edges of the clock signal CK are consecutive, the period P As a result, the risk of the drive circuit 50 being included in the trapezoidal During the period when the drive signal COM is output with successive waveforms Adp, Bdp, and Cdp, This reduces the possibility that the information output circuit 26 will determine that the voltage value of the drive signal COM is constant.

[0201] Here, the control circuit 500 is an example of a temperature information acquisition circuit, and The digital temperature information dtc is an example of the temperature information. This is an example of a first D-type flip-flop circuit. The data signal Do1 is an example of a first data signal, and the D-type flip-flop 594 is an example of a second D-type This is an example of a flip-flop circuit. The data signal output by the D-type flip-flop 594 is Do2 is an example of a second data signal, and the OR circuit 596 is an example of a logic element. It is also a threshold value for determining the voltage value of the drive signal COM in the comparison circuit 580. The voltage Vch is an example of a predetermined threshold and a threshold voltage value, and the comparison result signal output by the comparison circuit 580 is Among the logic levels of signal Vcr, H level is an example of the first logic level, and L level is an example of the second logic level. The clock signal CK is an example of a clock signal. The electrode 360 ​​is an example of a first electrode, the electrode 380 is an example of a second electrode, and the printhead The direction along the Z axis in the print head 22 is an example of the stacking direction. The +Z side is an example of one side, and the -Z side of the print head 22 is an example of the other side. The resistive wiring 401 is an example of a temperature detection unit.

[0202] 8. Action and Effects In the liquid ejection device 1 and head unit 20 of this embodiment configured as above, a temperature information output circuit 2 for acquiring a head temperature signal TC corresponding to the temperature of the print head 22; 6 is a digital temperature information dt corresponding to the temperature of the print head 22 from the head temperature signal TC. A control circuit 500 that acquires digital temperature information dtc, and a timing controller 500 that acquires digital temperature information dtc. and a timing control circuit 590 for controlling the timing of the , determine whether the voltage value of the drive signal COM is constant, and based on the determination result, This controls the timing of acquiring digital temperature information DTC in 500. The head temperature signal TC acquired by the circuit 500 is transmitted through the driving signal VOUT and the vibration of the diaphragm 350. Noise caused by displacement and instantaneous temperature changes in the ink stored in the pressure chamber 312 As a result, the head temperature signal obtained by the temperature information output circuit 26 is The accuracy of the signal TC, that is, the accuracy of detecting the temperature of the pressure chamber 312 to be detected, is improved, and the temperature information output The reliability of the temperature information signal TI output by the circuit 26 is improved. The accuracy of temperature detection of 2 is improved.

[0203] In the liquid ejection device 1 and the head unit 20 of this embodiment, The print head 22 includes an electrode 360, an electrode 380, and a piezoelectric element 370. In the direction along the Z axis where the pole 360, the electrode 380, and the piezoelectric body 370 are stacked, The body 370 is located between the electrode 360 ​​and the electrode 380 and receives a drive signal COM to drive the pressure sensor. and a piezoelectric element 60, and a +Z side, which is one side of the piezoelectric element 60 in the direction along the Z axis, The vibration plate 350 is deformed by the driving of the piezoelectric element 60, and the vibration plate 350 is moved along the Z axis. The ink is stored in the +Z direction, and the deformation of the vibration plate 350 A pressure chamber substrate 310 in which a pressure chamber 312 whose volume changes is provided, and The nozzle 321 ejects ink according to the change in volume, and the vibration plate 350 is arranged along the Z axis. A resistor located on the −Z side, which is the other side of the direction in which the pressure is applied, acquires a temperature corresponding to the temperature of the pressure chamber 312. Even in the case where the wiring 401 is included, the timing control circuit 590 controls the drive signal COM. It is determined whether the voltage value is constant, and based on the determination result, the digital By controlling the timing of acquiring the temperature information dtc, the control circuit 500 acquires The head temperature signal TC is transmitted to the driving signal VOUT, the displacement of the diaphragm 350, and the pressure chamber 31. 2. The possibility of noise, etc. being superimposed due to instantaneous temperature changes in the ink stored in Therefore, the accuracy of detecting the temperature of the print head 22 is further improved.

[0204] In addition, in the liquid ejection device 1 and the head unit 20 of this embodiment, the print head 22 Since the accuracy of detecting the temperature of the print head 22 is improved, the head temperature signal The drive signal COM output by the drive circuit 50 is corrected based on the signal TC. The accuracy of ink ejection from the head 22 can be improved.

[0205] 9. Variations In the liquid ejection device 1 of the present embodiment described above, the comparison circuit 580 The voltage value of the drive signal COM is compared with the switching voltage Vch, and the voltage value of the drive signal COM is the voltage of the switching voltage Vch. When the voltage value of the drive signal COM is greater than the voltage of the switching voltage Vch, it becomes H level. In the above explanation, it is assumed that the comparison result signal Vcr is output as an L level signal when the value is smaller than the reference value. However, the comparison circuit 580 compares the voltage value of the drive signal COM with the switching voltage Vch, and When the voltage value of COM is greater than the voltage value of the switching voltage Vch, it becomes L level, and the drive signal A comparison result signal that becomes H level when the voltage value of COM is smaller than the voltage value of the switching voltage Vch. In this case, the timing control circuit 590 may output a signal Vcr. 596, and the control circuit 500 has an AND circuit. When the control signal Tgi changes from L level to H level, the A / D converter 530 starts operating. By outputting an enable signal EN1 that enables the operation, the same operation as in the above-described embodiment can be performed. At this time, an AND circuit provided in place of the OR circuit 596 is used to This corresponds to one example.

[0206] In the liquid ejection device 1 of this embodiment, a resistor wire constituting a part of the temperature detection circuit 250 Although the explanation has been given using an example in which the wire 401 is formed on the diaphragm 350, 250 is the temperature of the print head 22 and the ink stored in the print head 22 The present invention is not limited to such a configuration as long as it can detect the temperature.

[0207] Although the embodiments and modifications have been described above, the present invention is not limited to these embodiments. It is possible to implement the invention in various ways without departing from the spirit of the invention. For example, the above embodiments can be combined as appropriate.

[0208] The present invention has substantially the same configuration (for example, function, method and result) as the configuration described in the embodiment. The present invention also includes the following embodiments: The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. A configuration that can achieve the same effect or purpose as the configuration described in the above embodiment. The present invention also includes a configuration in which publicly known technology is added to the configuration described in the embodiment. .

[0209] The following can be derived from the above-described embodiment.

[0210] One aspect of the liquid ejection device is a drive circuit that outputs a drive signal; a print head that receives the drive signal and ejects liquid; a temperature information output circuit for acquiring a head temperature signal corresponding to the temperature of the print head; Equipped with The temperature information output circuit temperature information that corresponds to the temperature of the print head from the head temperature signal; an information acquisition circuit; Timing control for controlling the timing at which the temperature information acquisition circuit acquires the temperature information The circuit and and The timing control circuit determines whether the voltage value of the drive signal is constant, and Based on the result, the timing at which the temperature information acquisition circuit acquires the temperature information is controlled. Outputs a timing control signal.

[0211] In this liquid ejection device, the timing control circuit determines whether the voltage value of the drive signal is constant or not. Based on the result of the judgment, the timing when the temperature information acquisition circuit acquires temperature information is controlled. By outputting a timing control signal that controls the temperature, the temperature information acquisition circuit Obtain temperature information corresponding to the print head temperature from the head temperature signal over a certain period of time. This allows the temperature information acquisition circuit to obtain the print head temperature information from the head temperature signal. The temperature information corresponding to the temperature of the nozzle is acquired at the timing when the liquid from the print head is released. This reduces the possibility that noise caused by the ejection operation will be superimposed on the temperature information. This improves the accuracy of the temperature information acquired by the acquisition circuit.

[0212] In one aspect of the liquid ejection device, When it is determined that the voltage value of the drive signal is constant, the timing control circuit The temperature information acquisition circuit may be controlled to acquire the temperature information.

[0213] In this liquid ejection device, the voltage value of the drive signal is constant for a certain period of time. Temperature information corresponding to the temperature of the print head can be obtained from the head temperature signal. This allows the temperature information acquisition circuit to obtain a temperature according to the print head temperature from the head temperature signal. Noise caused by the ejection of liquid from the print head when acquiring information As a result, the temperature information acquired by the temperature information acquisition circuit is The accuracy of information is improved.

[0214] In one aspect of the liquid ejection device, The timing control circuit detects whether the voltage value of the drive signal is below a predetermined threshold value for a predetermined time. Then, it may be determined that the voltage value of the drive signal is constant.

[0215] In this liquid ejection device, the voltage value of the drive signal is constant for a certain period of time. Temperature information corresponding to the temperature of the print head can be obtained from the head temperature signal. This allows the temperature information acquisition circuit to obtain a temperature according to the print head temperature from the head temperature signal. Noise caused by the ejection of liquid from the print head when acquiring information As a result, the temperature information acquired by the temperature information acquisition circuit is The accuracy of information is improved.

[0216] In one aspect of the liquid ejection device, The temperature information output circuit The voltage value of the drive signal is compared with a threshold voltage value, and the voltage value of the drive signal is compared with the threshold voltage value. a first logic level when the voltage value of the drive signal is greater than the threshold voltage value; a comparison circuit that outputs a comparison result signal that is at a second logic level when the difference is smaller than the first logic level; The timing control circuit The comparison result signal is input to a first D-type flip-flop circuit and a second D-type flip-flop circuit. a drop circuit; A first data signal output from the first D-type flip-flop circuit and a second D-type flip-flop circuit a logic element to which the second data signal output by the flip-flop circuit is input; Including, The first D-type flip-flop circuit outputs the comparison result at the rising edge of the clock signal. outputting the first data signal according to the logic level of the result signal; The second D-type flip-flop circuit is configured to: outputting the second data signal according to the logic level of the comparison result signal; The logic element determines the logic level of the first data signal and the logic level of the second data signal. The timing control signal may be output in accordance with the rule.

[0217] In this liquid ejection device, whether or not the voltage value of the drive signal is constant can be determined with a simple configuration. It can be determined.

[0218] In one aspect of the liquid ejection device, The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. It may be longer than the maximum time that the circuit outputs a signal at the second logic level.

[0219] In this liquid ejection device, during the period when the voltage value of the drive signal changes, The risk of obtaining temperature information corresponding to the temperature of the print head from the head temperature signal is reduced. This allows the temperature information acquisition circuit to determine the temperature of the print head from the head temperature signal. When the temperature information is acquired, the temperature information is This further reduces the risk of noise and other such issues being superimposed on the temperature information. This improves the accuracy of the temperature information acquired.

[0220] In one aspect of the liquid ejection device, The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. The time may be shorter than the minimum time during which the circuit outputs a signal of the first logic level.

[0221] In this liquid ejection device, during the period when the voltage value of the drive signal changes, The risk of obtaining temperature information corresponding to the temperature of the print head from the head temperature signal is reduced. This allows the temperature information acquisition circuit to determine the temperature of the print head from the head temperature signal. When the temperature information is acquired, the temperature information is This further reduces the risk of noise and other such issues being superimposed on the temperature information. This improves the accuracy of the temperature information acquired.

[0222] In one aspect of the liquid ejection device, The print head includes: The piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body, The piezoelectric element is positioned between the first electrode and the second electrode in the stacking direction. a piezoelectric element that receives the drive signal and is driven; The piezoelectric element is positioned on one side of the stacking direction and deformed by driving the piezoelectric element. a diaphragm that The liquid is stored in the cavity, and the cavity is located on one side of the vibration plate in the stacking direction. a pressure chamber substrate provided with a pressure chamber whose volume changes with deformation of the moving plate; a nozzle that ejects liquid in response to a change in the volume of the pressure chamber; a pressure chamber temperature sensor that is located on the other side of the vibration plate in the stacking direction and that responds to the temperature of the pressure chamber; a temperature detection unit that outputs a head temperature signal; may have

[0223] In this liquid ejection device, even if the temperature detection unit is located near the pressure chamber, the drive signal The voltage value of the signal is constant for a certain period of time, and the temperature information acquisition circuit detects the print head temperature from the head temperature signal. Since it is possible to obtain temperature information according to the temperature of the It is possible.

[0224] In one aspect of the liquid ejection device, The drive circuit may output the drive signal corrected based on the head temperature signal. good.

[0225] In this liquid ejection device, the accuracy of temperature information acquisition in the temperature information acquisition circuit can be improved. Therefore, the accuracy of the correction of the drive signal corrected based on the temperature information is improved, and the print head This improves the accuracy of liquid ejection from the nozzle.

[0226] One aspect of the head unit is a print head that receives a drive signal and ejects liquid; a temperature information output circuit for acquiring a head temperature signal corresponding to the temperature of the print head; Equipped with The temperature information output circuit temperature information that corresponds to the temperature of the print head from the head temperature signal; an information acquisition circuit; Timing control for controlling the timing at which the temperature information acquisition circuit acquires the temperature information The circuit and and The timing control circuit determines whether the voltage value of the drive signal is constant, and Based on the result, the timing at which the temperature information acquisition circuit acquires the temperature information is controlled. Outputs a timing control signal.

[0227] In this head unit, the timing control circuit checks whether the voltage value of the drive signal is constant. Based on the result of the judgment, the timing at which the temperature information acquisition circuit acquires temperature information is determined. By outputting a timing control signal to control the temperature information acquisition circuit, the voltage value of the drive signal temperature information corresponding to the print head temperature is acquired from the head temperature signal for a certain period of time. This allows the temperature information acquisition circuit to obtain the temperature information from the head temperature signal. The liquid from the print head is measured at the timing when temperature information corresponding to the head temperature is acquired. As a result, the possibility that noises caused by the ejection operation are superimposed on the temperature information is reduced. The accuracy of the temperature information acquired by the acquisition circuit is improved.

[0228] In one aspect of the head unit, When it is determined that the voltage value of the drive signal is constant, the timing control circuit The temperature information acquisition circuit may be controlled to acquire the temperature information.

[0229] In this head unit, the voltage value of the drive signal is maintained at a constant value for a certain period of time. However, temperature information corresponding to the temperature of the print head can be obtained from the head temperature signal. This allows the temperature information acquisition circuit to obtain a temperature according to the print head temperature from the head temperature signal. At the timing when the liquid quality information is acquired, the noise caused by the liquid ejection operation from the print head is As a result, the temperature information acquired by the temperature information acquisition circuit is The accuracy of the degree information is improved.

[0230] In one aspect of the head unit, The timing control circuit detects whether the voltage value of the drive signal is below a predetermined threshold value for a predetermined time. Then, it may be determined that the voltage value of the drive signal is constant.

[0231] In this head unit, the voltage value of the drive signal is maintained at a constant value for a certain period of time. However, temperature information corresponding to the temperature of the print head can be obtained from the head temperature signal. This allows the temperature information acquisition circuit to obtain a temperature according to the print head temperature from the head temperature signal. At the timing when the liquid quality information is acquired, the noise caused by the liquid ejection operation from the print head is As a result, the temperature information acquired by the temperature information acquisition circuit is The accuracy of the degree information is improved.

[0232] In one aspect of the head unit, The temperature information output circuit The voltage value of the drive signal is compared with a threshold voltage value, and the voltage value of the drive signal is compared with the threshold voltage value. a first logic level when the voltage value of the drive signal is greater than the threshold voltage value; a comparison circuit that outputs a comparison result signal that is at a second logic level when the difference is smaller than the first logic level; The timing control circuit The comparison result signal is input to a first D-type flip-flop circuit and a second D-type flip-flop circuit. a drop circuit; A first data signal output from the first D-type flip-flop circuit and a second D-type flip-flop circuit a logic element to which the second data signal output by the flip-flop circuit is input; Including, The first D-type flip-flop circuit outputs the comparison result at the rising edge of the clock signal. outputting the first data signal according to the logic level of the result signal; The second D-type flip-flop circuit is configured to: outputting the second data signal according to the logic level of the comparison result signal; The logic element determines the logic level of the first data signal and the logic level of the second data signal. The timing control signal may be output in accordance with the rule.

[0233] In this head unit, whether the voltage value of the drive signal is constant or not can be determined with a simple configuration. It is possible to determine:

[0234] In one aspect of the head unit, The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. It may be longer than the maximum time that the circuit outputs a signal at the second logic level.

[0235] In this head unit, the temperature information acquisition circuit The risk of the path obtaining temperature information corresponding to the temperature of the print head from the head temperature signal is reduced. This allows the temperature information acquisition circuit to convert the head temperature signal into the print head temperature. The temperature information is acquired according to the timing of the liquid ejection operation from the print head. This further reduces the risk of noise, etc., being superimposed on the temperature information. This improves the accuracy of the temperature information acquired by the path.

[0236] In one aspect of the head unit, The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. The time may be shorter than the minimum time during which the circuit outputs a signal of the first logic level.

[0237] In this head unit, the temperature information acquisition circuit The risk of the path obtaining temperature information corresponding to the temperature of the print head from the head temperature signal is reduced. This allows the temperature information acquisition circuit to convert the head temperature signal into the print head temperature. The temperature information is acquired according to the timing of the liquid ejection operation from the print head. This further reduces the risk of noise, etc., being superimposed on the temperature information. This improves the accuracy of the temperature information acquired by the path.

[0238] In one aspect of the head unit, The print head includes: The piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body, The piezoelectric element is positioned between the first electrode and the second electrode in the stacking direction. a piezoelectric element that receives the drive signal and is driven; The piezoelectric element is positioned on one side of the stacking direction and deformed by driving the piezoelectric element. a diaphragm that The liquid is stored in the cavity, and the cavity is located on one side of the vibration plate in the stacking direction. a pressure chamber substrate provided with a pressure chamber whose volume changes with deformation of the moving plate; a nozzle that ejects liquid in response to a change in the volume of the pressure chamber; a pressure chamber temperature sensor that is located on the other side of the vibration plate in the stacking direction and that responds to the temperature of the pressure chamber; a temperature detection unit that outputs a head temperature signal; may have

[0239] In this head unit, even if the temperature detection unit is located near the pressure chamber, When the signal voltage is constant, the temperature information acquisition circuit detects the temperature of the head and Since it is possible to obtain temperature information according to the temperature of the head, it is possible to obtain temperature information with high accuracy. It is possible.

[0240] In one aspect of the head unit, The drive signal may be corrected based on the head temperature signal.

[0241] In this head unit, the accuracy of temperature information acquisition in the temperature information acquisition circuit can be improved. Therefore, the accuracy of the correction of the drive signal corrected based on the temperature information is improved, and the print head This improves the accuracy of liquid ejection from the nozzle. [Explanation of symbols]

[0242] 1...liquid ejection device, 10...control unit, 20...head unit, 21...carriage, 22...print head, 26...temperature information output circuit, 28...temperature detection circuit, 30...moving unit 31...carriage motor, 32...endless belt, 40...transport unit, 41...transport Motor, 42...conveyor roller, 50...drive circuit, 52...reference voltage output circuit, 60...piezoelectric Element, 90... ink container, 92... encoder sensor, 94... alarm circuit, 100... control Circuit, 200... drive signal selection circuit, 210... selection control circuit, 212... shift register, 214... latch circuit, 216... decoder, 230... selection circuit, 232... inverter, 234...transfer gate, 250...temperature detection circuit, 252, 254...resistors, 310 ...pressure chamber substrate, 311...partition wall, 312...pressure chamber, 312a, 312b...end portion, 315...connection Plate, 316... nozzle communication passage, 317... first manifold portion, 318... second manifold portion, 319...supply communication passage, 320...nozzle plate, 321...nozzle, 330...protection substrate , 331...holding portion, 332...through hole, 340...case member, 341...accommodating portion, 342...third 3 manifold part, 343... connection port, 344... supply port, 345... compliance board, 346...sealing film, 347...fixed substrate, 348...opening, 349...compliance portion, 3 50...diaphragm, 351...elastic membrane, 352...insulating membrane, 360...electrodes, 360a, 360b ...end portion, 370...piezoelectric body, 370a, 370b...end portion, 371...groove portion, 380...electrode, 3 80a, 380b...end portions, 385...wiring portion, 391...individual lead electrodes, 392...common lead Lead electrodes, 392a, 392b...extension portions, 393, 393a, 393b...measurement lead electrodes , 400... manifold, 401... resistance wiring, 410... active portion, 415... inactive portion, 42 0...wiring board, 421...integrated circuit, 500...control circuit, 501...request analysis unit, 502... Lock signal output unit 503...temperature information output unit 504...correction value calculation unit 505...memory Control unit, 510... multiplexer, 520... amplifier circuit, 530... A / D converter, 550...amplification circuit, 560...A / D converter, 570...memory circuit, 580...comparison circuit , 582... Comparator, 584, 586... Resistor, 590... Timing control circuit, 59 2,594...D-type flip-flop, 596...OR circuit, P...medium

Claims

1. a drive circuit that outputs a drive signal; a print head that receives the drive signal and ejects liquid; a temperature information output circuit for acquiring a head temperature signal corresponding to the temperature of the print head; Equipped with The temperature information output circuit temperature information that corresponds to the temperature of the print head from the head temperature signal; an information acquisition circuit; Timing control for controlling the timing at which the temperature information acquisition circuit acquires the temperature information The circuit and and The timing control circuit determines whether the voltage value of the drive signal is constant, and Based on the result, the timing at which the temperature information acquisition circuit acquires the temperature information is controlled. outputting a timing control signal; A liquid ejection device characterized by:

2. When it is determined that the voltage value of the drive signal is constant, the timing control circuit controlling the temperature information acquisition circuit to acquire the temperature information; The liquid ejection device according to claim 1 .

3. The timing control circuit detects whether the voltage value of the drive signal is below a predetermined threshold value for a predetermined time. and determining that the voltage value of the drive signal is constant.

3. The liquid ejection device according to claim 2.

4. The temperature information output circuit The voltage value of the drive signal is compared with a threshold voltage value, and the voltage value of the drive signal is compared with the threshold voltage value. a first logic level when the voltage value of the drive signal is greater than the threshold voltage value; a comparison circuit that outputs a comparison result signal that is at a second logic level when the difference is smaller than the first logic level; The timing control circuit The comparison result signal is input to a first D-type flip-flop circuit and a second D-type flip-flop circuit. a drop circuit; a first data signal output from the first D-type flip-flop circuit and a second D-type flip-flop circuit; a logic element to which the second data signal output from the flip-flop circuit is input; Including, The first D-type flip-flop circuit outputs the comparison result at the rising edge of the clock signal. outputting the first data signal according to the logic level of the result signal; The second D-type flip-flop circuit is configured to: outputting the second data signal according to the logic level of the comparison result signal; The logic element determines the logic level of the first data signal and the logic level of the second data signal. outputting the timing control signal according to the The liquid ejection device according to claim 1 .

5. The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. longer than the maximum time that the circuit outputs a signal of the second logic level; 5. The liquid ejection device according to claim 4.

6. The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. a minimum time during which the circuit outputs a signal of the first logic level; 5. The liquid ejection device according to claim 4.

7. The print head includes: The piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body, The piezoelectric element is positioned between the first electrode and the second electrode in the stacking direction. a piezoelectric element that receives the drive signal and is driven; The piezoelectric element is positioned on one side of the stacking direction and deformed by driving the piezoelectric element. a diaphragm that The liquid is stored in the cavity, and the cavity is located on one side of the vibration plate in the stacking direction. a pressure chamber substrate provided with a pressure chamber whose volume changes with deformation of the moving plate; a nozzle that ejects liquid in response to a change in the volume of the pressure chamber; a pressure chamber temperature sensor that is located on the other side of the vibration plate in the stacking direction and that responds to the temperature of the pressure chamber; a temperature detection unit that outputs a head temperature signal; having 7. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

8. the drive circuit outputs the drive signal corrected based on the head temperature signal. The liquid ejection device according to claim 1 .

9. a print head that receives a drive signal and ejects liquid; a temperature information output circuit for acquiring a head temperature signal corresponding to the temperature of the print head; Equipped with The temperature information output circuit temperature information that corresponds to the temperature of the print head from the head temperature signal; an information acquisition circuit; Timing control for controlling the timing at which the temperature information acquisition circuit acquires the temperature information The circuit and and The timing control circuit determines whether the voltage value of the drive signal is constant, and Based on the result, the timing at which the temperature information acquisition circuit acquires the temperature information is controlled. outputting a timing control signal; A head unit characterized by:

10. When it is determined that the voltage value of the drive signal is constant, the timing control circuit controlling the temperature information acquisition circuit to acquire the temperature information; 10. The head unit according to claim 9.

11. The timing control circuit detects whether the voltage value of the drive signal is below a predetermined threshold value for a predetermined time. and determining that the voltage value of the drive signal is constant. The head unit according to claim 10 .

12. The temperature information output circuit The voltage value of the drive signal is compared with a threshold voltage value, and the voltage value of the drive signal is compared with the threshold voltage value. a first logic level when the voltage value of the drive signal is greater than the threshold voltage value; a comparison circuit that outputs a comparison result signal that is at a second logic level when the difference is smaller than the first logic level; The timing control circuit The comparison result signal is input to a first D-type flip-flop circuit and a second D-type flip-flop circuit. a drop circuit; a first data signal output from the first D-type flip-flop circuit and a second D-type flip-flop circuit; a logic element to which the second data signal output from the flip-flop circuit is input; Including, The first D-type flip-flop circuit outputs the comparison result at the rising edge of the clock signal. outputting the first data signal according to the logic level of the result signal; The second D-type flip-flop circuit is configured to: outputting the second data signal according to the logic level of the comparison result signal; The logic element determines the logic level of the first data signal and the logic level of the second data signal. outputting the timing control signal according to the 10. The head unit according to claim 9.

13. The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. longer than the maximum time that the circuit outputs a signal of the second logic level; 13. The head unit according to claim 12.

14. The length of a half cycle of the clock signal is set to be equal to or longer than the length of the comparison signal during one cycle of the drive signal. a minimum time during which the circuit outputs a signal of the first logic level; 13. The head unit according to claim 12.

15. The print head includes: The piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body, The piezoelectric element is positioned between the first electrode and the second electrode in the stacking direction. a piezoelectric element that receives the drive signal and is driven; The piezoelectric element is positioned on one side of the stacking direction and deformed by driving the piezoelectric element. a diaphragm that The liquid is stored in the cavity, and the cavity is located on one side of the vibration plate in the stacking direction. a pressure chamber substrate provided with a pressure chamber whose volume changes with deformation of the moving plate; a nozzle that ejects liquid in response to a change in the volume of the pressure chamber; a pressure chamber temperature sensor that is located on the other side of the vibration plate in the stacking direction and that responds to the temperature of the pressure chamber; a temperature detection unit that outputs a head temperature signal; having 15. The head unit according to claim 9, wherein the first and second electrodes are electrically connected to each other.

16. the drive signal is corrected based on the head temperature signal; 10. The head unit according to claim 9.

Images