Liquid ejection device

Abstract

The present application provides a liquid ejecting apparatus capable of reducing variation in temperature detection characteristics of a temperature detection unit provided inside a print head. A temperature information output circuit is inputted with a cell temperature signal outputted by a cell temperature detection circuit possessed by a head unit that ejects liquid to a medium based on a drive signal, and a head temperature signal including head temperature information corresponding to a temperature of the print head outputted by a head temperature detection unit of the print head, and outputs a temperature information signal, and the temperature information output circuit corrects the head temperature information outputted as the temperature information signal based on the cell temperature information and the head temperature information inputted in the case where a heat generating mechanism generates heat at a prescribed temperature.

Description

Technical Field

[0001] This invention relates to a liquid ejection device. Background Technology

[0002] A known liquid ejection device comprises a printhead having a piezoelectric element, a pressure chamber, and a nozzle communicating with the pressure chamber. The printhead, driven by the piezoelectric element, changes the volume of the pressure chamber, thereby ejecting liquid supplied to the pressure chamber from the nozzle. In liquid ejection devices with such printheads, techniques are known for controlling the ejection process by driving the piezoelectric element based on the temperature of the ink stored in the printhead, thereby achieving ejection control suitable for the temperature of the ink.

[0003] For example, Patent Document 1 discloses the following technology: by providing a temperature detection unit inside a printhead having a piezoelectric element, a pressure chamber and a nozzle to detect the temperature of the pressure chamber containing ink, the temperature difference between the temperature detected by the temperature detection unit and the temperature inside the pressure chamber can be reduced, thereby improving the detection accuracy of the temperature of the ink stored in the pressure chamber.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2022-124599

[0005] However, Patent Document 1 does not take into account the deviation of the temperature detection characteristics of the temperature detection unit located inside the printhead, leaving room for improvement. Summary of the Invention

[0006] One aspect of the liquid ejection device according to the present invention comprises:

[0007] The head unit ejects liquid into the medium based on a drive signal; and

[0008] Fever-inducing institutions

[0009] The head unit has:

[0010] The printhead ejects liquid based on the drive signal;

[0011] A unit temperature detection circuit detects the temperature of the head unit as unit temperature information and outputs a unit temperature signal including the unit temperature information; and

[0012] The temperature information output circuit receives the unit temperature signal and a head temperature signal, which includes head temperature information corresponding to the temperature of the print head, and outputs a temperature information signal.

[0013] The printhead includes:

[0014] A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode and receives the driving signal to drive it.

[0015] The vibrating plate is located on one side of the piezoelectric element in the stacking direction and is deformed by the piezoelectric element.

[0016] A pressure chamber substrate, located on one side of the vibrating plate in the stacking direction, is provided with a pressure chamber whose volume varies according to the deformation of the vibrating plate;

[0017] A nozzle that ejects liquid according to changes in the volume of the pressure chamber; and

[0018] The head temperature detection unit, located on the opposite side of the vibrating plate in the stacking direction, detects the head temperature information corresponding to the temperature of the pressure chamber and outputs it as the head temperature signal.

[0019] The temperature information output circuit corrects the head temperature information, which is output as a temperature information signal, based on the unit temperature information and the head temperature information input when the heating mechanism heats up at a specified temperature. Attached Figure Description

[0020] Figure 1 This is a diagram showing the general structure of a liquid ejection device.

[0021] Figure 2 This is a top view of the heating unit when viewed along the Z-axis.

[0022] Figure 3 It is shown Figure 2 The cross-sectional view of section Aa is shown.

[0023] Figure 4 This is an exploded perspective view showing the structure of the print head.

[0024] Figure 5 This is a top view of the printhead when viewed along the Z-axis.

[0025] Figure 6 It is shown Figure 5 The cross-sectional view of section Bb is shown.

[0026] Figure 7 It is shown Figure 6 Details of the main parts, including the main part detail diagram.

[0027] Figure 8 It is shown Figure 5 The cross-sectional view of section Cc shown.

[0028] Figure 9 This is a diagram showing the functional configuration of a liquid ejection device.

[0029] Figure 10 This is a diagram showing an example of the signal waveform of the drive signal COM.

[0030] Figure 11 This is a diagram showing the configuration of the drive signal selection circuit.

[0031] Figure 12 This is a diagram illustrating an example of the decoded content in the decoder.

[0032] Figure 13 This is a diagram showing the configuration of the selection circuit.

[0033] Figure 14 This is a diagram used to illustrate the operation of the drive signal selection circuit.

[0034] Figure 15 This is a diagram showing the functional structure of the temperature information output circuit.

[0035] Figure 16 This is a diagram used to illustrate the operation of the temperature information output circuit.

[0036] Figure 17 This is a diagram used to illustrate an example of the calculation and processing of the correction function.

[0037] Figure 18 This is a diagram illustrating an example of temperature information output processing.

[0038] Explanation of reference numerals in the attached figures

[0039] 1: Liquid ejection device; 10: Control unit; 20: Head unit; 21: Carriage; 22: Printhead; 24: Temperature detection circuit; 26: Temperature information output circuit; 28: Temperature detection circuit; 30: Moving unit; 31: Carriage motor; 32: Circular belt; 40: Conveying unit; 41: Conveying motor; 42: Conveying roller; 50: Drive circuit; 52: Reference voltage output circuit; 60: Piezoelectric element; 80: Heating unit; 82: Media support; 84: Heater; 90: Ink container; 92: Linear encoder; 100: Control circuit; 200: Drive signal selection circuit; 21 0: Selection control circuit; 212: Shift register; 214: Latch circuit; 216: Decoder; 230: Selection circuit; 232: Inverter; 234: Transmission gate; 310: Pressure chamber substrate; 311: Partition plate; 312: Pressure chamber; 312a, 312b: Ends; 315: Connecting plate; 316: Nozzle connecting path; 317: First manifold section; 318: Second manifold section; 319: Supply connecting path; 320: Nozzle plate; 321: Nozzle; 330: Protective substrate; 331: Holding part; 332: Through hole; 340: Housing component; 341: Receiving part; 342: Third manifold section; 343: Connection port; 344: Supply port; 345: Flexible substrate; 346: Sealing film; 347: Fixed substrate; 348: Opening; 349: Flexible section; 350: Vibrating plate; 351: Elastic film; 352: Insulating film; 360: Electrode; 360a, 360b: Ends; 370: Piezoelectric element; 370a, 370b: Ends; 371: Groove; 380: Electrode; 380a, 380b: Ends; 385: Wiring section; 391: Single lead electrode; 392: Common lead electrode; 392a, 392b: Extension section; 393, 3 93a, 393b: Measurement lead electrodes; 400: Manifold; 401: Resistor wiring; 410: Active part; 415: Inactive part; 420: Wiring substrate; 421: Integrated circuit; 500: Control circuit; 502: Request parsing unit; 504: Correction function calculation unit; 506: Correction output unit; 508: Memory control unit; 510-1~510~n, 520: Amplifier circuit; 530: Multiplexer; 540, 550: AD conversion circuit; 560: Storage circuit; 840: Ceramic substrate; 842: Heating resistor; 844: Protection component; P: Dielectric. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described using the accompanying drawings. The drawings are provided for ease of explanation. It should be noted that the embodiments described below do not unduly limit the scope of the invention as defined in the claims. Furthermore, not all elements described below are essential components of the present invention.

[0041] 1. Structure of the liquid ejection device

[0042] Structure of the liquid ejection device

[0043] Figure 1 This diagram shows a schematic configuration of the liquid ejection device 1. The liquid ejection device 1 of this embodiment is a so-called serial printing inkjet printer that ejects ink onto a medium P transported in the transport direction by reciprocating a carriage 21 carrying a printhead 22 that ejects ink (an example of liquid ink) along the scanning axis, thereby forming a desired image on the medium P. Furthermore, the medium P in the liquid ejection device 1 can be any printing material such as printing paper, resin film, or fabric. It should be noted that the liquid ejection device 1 is not limited to a serial printing inkjet printer; it can also be a line printing inkjet printer. Furthermore, the liquid ejection device 1 is not limited to an inkjet printer; it can also be a pigment ejection device used in the manufacture of color filters for liquid crystal displays, an electrode material ejection device used in the electrode formation of organic EL displays, FED (fiber emitting diode) displays, etc., a biological organic matter ejection device used in the manufacture of biochips, a three-dimensional modeling device, and a printing and dyeing device, etc.

[0044] Here, in the following explanation, three mutually orthogonal spatial axes, namely the X-axis, Y-axis, and Z-axis, will be used. Furthermore, in the following explanation, when determining the orientation along the X-axis, Y-axis, and Z-axis respectively, the tip of the arrow representing the direction along the X-axis in the illustration will be called the +X side, and the starting point side will be called the -X side; the tip of the arrow representing the direction along the Y-axis in the illustration will be called the +Y side, and the starting point side will be called the -Y side; the tip of the arrow representing the direction along the Z-axis in the illustration will be called the +Z side, and the starting point side will be called the -Z side.

[0045] like Figure 1 As shown, the liquid ejection device 1 includes a control unit 10, a head unit 20, a moving unit 30, a conveying unit 40, a heating unit 80, and an ink container 90.

[0046] The ink container 90 stores various inks that are sprayed onto the medium P. The ink container 90 can be an ink cartridge, a bag-shaped ink pouch formed of a flexible membrane, or an ink canister for refilling ink, etc.

[0047] The control unit 10 includes processing circuits such as a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), and storage circuits such as a semiconductor memory, and controls the various elements of the liquid ejection device 1, including the head unit 20.

[0048] The printhead unit 20 includes a carriage 21 and a plurality of printheads 22. The carriage 21 is fixed to the annular belt 32 included in the moving unit 30 (described later). The plurality of printheads 22 are mounted on the carriage 21. Furthermore, the control signal Ctrl-H and the drive signal COM output from the control unit 10 are respectively input to the plurality of printheads 22. Ink stored in the ink container 90 is then supplied to the plurality of printheads 22 via tubes (not shown). Based on the input control signal Ctrl-H and drive signal COM, the printheads 22 eject the ink supplied from the ink container 90. In this case, the direction in which the printheads 22 eject ink along the Z-axis, i.e., the direction along the Z-axis from the -Z side to the +Z side, is sometimes referred to as the ejection direction.

[0049] The moving unit 30 includes a carriage motor 31 and an annular belt 32. The carriage motor 31 operates based on a control signal Ctrl-C input from the control unit 10. The annular belt 32 extends along the X-axis and rotates with the operation of the carriage motor 31. As a result, the carriage 21, fixed to the annular belt 32, moves along the X-axis. That is, the moving unit 30 causes the plurality of printheads 22 mounted on the carriage 21 to reciprocate along the X-axis. Here, in the following description, the direction along the X-axis in which the plurality of printheads 22 mounted on the carriage 21 move is sometimes referred to as the scanning direction.

[0050] The conveying unit 40 includes a conveying motor 41 and a conveying roller 42. The conveying motor 41 operates based on a control signal Ctrl-T input from the control unit 10. The conveying roller 42 rotates with the operation of the conveying motor 41 while holding the medium P. As a result, the medium P held by the conveying roller 42 is conveyed along the Y-axis from the -Y side to the +Y side. That is, the conveying unit 40 conveys the medium P along the Y-axis from the -Y side to the +Y side. Here, in the following description, the direction of conveying the medium P from the -Y side to the +Y side is sometimes referred to as the conveying direction.

[0051] The heating unit 80 is located on the +Z side of the head unit 20, and supports the medium P conveyed by the conveying unit 40 on its -Z side surface. Furthermore, the heating unit 80 generates heat based on the control signal Ctrl-W input from the control unit 10. The heating unit 80 heats the supported medium P through the heat generated based on the control signal Ctrl-W. As a result, the medium P supported by the heating unit 80, and the ink adhering to the medium P, are dried. Consequently, the fixing properties of the ink adhering to the medium P are improved. In other words, the heating unit 80 has both a medium support function for supporting the medium P and a medium heating function for drying the medium P and the ink adhering to the medium P.

[0052] In the liquid ejection device 1 configured as described above, the moving unit 30 controls the reciprocating movement of the carriage 21 along the scanning direction, and the conveying unit 40 controls the conveying of the medium P supported by the heating unit 80 along the conveying direction. Furthermore, in conjunction with the reciprocating movement of the carriage 21 along the scanning direction and the conveying of the medium P in the conveying direction, the print head 22 mounted on the carriage 21 ejects ink. As a result, the ink ejected by the print head 22 can land on any surface of the medium P, forming a desired image on the medium P. At this time, the heating unit 80 dries the medium P and the ink landed on the medium P. This improves the fixing properties of the ink landed on the medium P. Consequently, the image quality formed on the medium P is improved. In other words, the liquid ejection device 1 of this embodiment includes a head unit 20 that ejects liquid to the medium P based on a drive signal COM and a heating unit 80.

[0053] Structure of heating unit 80

[0054] Next, a specific example of the structure of the heating unit 80 will be explained. Figure 2 This is a top view of the heating unit 80 viewed along the Z-axis. Additionally, in Figure 2 In the diagram, the head unit 20 located on the -Z side of the heating unit 80 is shown with dashed lines. For example... Figure 2 As shown, the heating unit 80 has a medium support portion 82 and a plurality of heaters 84.

[0055] The medium support 82 is a plate-shaped component extending along the XY plane formed by the X-axis and Y-axis, supporting the medium P being transported on the -Z side surface.

[0056] Each of the multiple heaters 84 is approximately rectangular, comprising a long side extending along the X-axis and a short side extending along the Y-axis. Furthermore, the heaters 84 are positioned such that the long side along the X-axis is greater than or equal to the width of the conveyed medium P along the X-axis, and the multiple heaters 84 are arranged side-by-side along the Y-axis in the heating unit 80. Additionally, the multiple heaters 84, together with the medium support portion 82, support the conveyed medium P on the -Z side surface. That is, the multiple heaters 84 are positioned such that the -Z side surface and the -Z side surface of the medium support portion 82 form approximately the same plane along the XY plane, and the medium P is conveyed along this same plane.

[0057] The multiple heaters 84 arranged as described above heat the medium P supported by the -Z side surfaces of the multiple heaters 84 and the -Z side surfaces of the medium support portion 82. This improves the fixing properties of the ink on the conveyed medium P.

[0058] Specifically, when viewing the heating unit 80 along the Z-axis, several of the plurality of heaters 84 are located further towards the -Y side than the head unit 20. That is, several of the plurality of heaters 84 are located further upstream than the head unit 20 in the transport direction of the transport medium P. The heaters 84 located further upstream than the head unit 20 preheat the transported medium P. As a result, the transported medium P is dried. Consequently, the affinity of the ink ejected from the printhead 22 for the medium P can be improved.

[0059] Furthermore, when viewing the heating unit 80 along the Z-axis, several of the plurality of heaters 84 are located at positions that overlap at least a portion with the printhead 22 included in the head unit 20. That is, in the direction along the Z-axis from which ink is ejected from the nozzles of the printhead 22, the heaters 84 of the heating unit 80 are located at positions that overlap at least a portion with the printhead 22. As a result, when ink ejected from the printhead 22 of the head unit 20 falls onto the medium P, the possibility of bleeding or other problems caused by the falling ink can be reduced.

[0060] Furthermore, when observing the heating unit 80 along the Z-axis, several of the plurality of heaters 84 are located further towards the +Y side than the head unit 20. That is, several of the plurality of heaters 84 are located further downstream of the head unit 20 in the conveying direction of the conveying medium P. The ink falling onto the medium P is dried by the heaters 84 located further downstream of the head unit 20. Thus, the ink falling onto the medium P is fixed to the medium P.

[0061] It should be noted that the configuration of the multiple heaters 84 in the heating unit 80 is only required to heat the conveyed medium P, and is not limited to any particular configuration. Figure 2 The configuration shown is as follows. For example, if the longer side of heater 84 along the X-axis is smaller than the width of the medium P being transported along the X-axis, multiple heaters 84 may also be arranged in a staggered pattern along the X-axis. Additionally, several of the multiple heaters 84 may be located on the -Y side of the medium P.

[0062] Next, a specific example of the structure of heater 84 will be described. Figure 3 This is a diagram showing an example of the structure of heater 84. Figure 2 The cross-sectional view of section Aa is shown. (As shown...) Figure 3 As shown, the heater 84 includes a ceramic substrate 840, a heating resistor 842, and a protective component 844.

[0063] The ceramic substrate 840 is a plate-shaped component extending along an XY plane formed by the X and Y axes, and the medium P is supported by the -Z side surface of the ceramic substrate 840. That is, the heater 84 is located such that the -Z side surface of the ceramic substrate 840 and the -Z side surface of the medium support portion 82 form approximately the same plane along the XY plane. The ceramic substrate 840 conducts the heat generated by the heating resistor 842. Thus, the medium P supported by the -Z side surface of the ceramic substrate 840 is heated. Such a ceramic substrate 840 can, for example, be made of ceramic materials such as alumina, silicon nitride, or aluminum nitride. Compared to glass such as quartz glass, alumina, silicon nitride, or aluminum nitride have high thermal conductivity. By constructing the ceramic substrate 840 using materials with such high thermal conductivity as alumina, silicon nitride, or aluminum nitride, the heat generated by the heating resistor 842 (described later) can be conducted more efficiently compared to using quartz glass. As a result, the rate of temperature rise and temperature fall of the heater 84 can be accelerated.

[0064] That is, the heater 84 in this embodiment is a ceramic heater that releases heat via ceramic, and the heating unit 80 is configured to include a ceramic heater. Therefore, compared to the case where the heating unit 80 is configured to include a quartz glass heater made of quartz glass or the like, the rate of temperature rise and fall of the heating unit 80 can be accelerated, and the temperature of the transported medium P can be controlled with high precision. As a result, the fixing properties of the ink on the medium P are improved, and the image quality formed on the medium P is improved.

[0065] In general, in ceramic heaters using ceramic substrates, as the area of ​​the ceramic heater increases, temperature deviations may occur at each part of the ceramic heater. Therefore, when heating the medium P using a single ceramic heater with a large area, it is difficult to accurately heat the medium P as a whole at the desired temperature. In contrast, the heating unit 80 of this embodiment uses multiple heaters 84 to heat the medium P. That is, compared with the case of heating the medium P using a single ceramic heater, the size of each heater 84 can be reduced. Therefore, in the heating unit 80 of this embodiment, compared with the case of heating the medium P using a single ceramic heater, the temperature of the medium P can be controlled more uniformly.

[0066] Furthermore, in the heater 84 according to this embodiment, a plurality of heating resistors 842 are used to heat the ceramic substrate 840. Therefore, compared to heating the ceramic substrate 840 using a single heating resistor 842, the temperature of the ceramic substrate 840 can be controlled more uniformly. This allows for more precise heating of the medium P transported on the -Z side surface of the ceramic substrate 840.

[0067] The heating resistor 842 is a non-metallic resistor that heats up when an electric current is applied; for example, a so-called "carbon wire" made of carbon fiber can be used. By using a non-metallic resistor as the heating resistor 842, the possibility of corrosion of the heating resistor 842 due to ink can be reduced compared to using a metallic resistor.

[0068] The protective component 844 is formed of glass, for example. In this embodiment, since the protective component 844 is formed of glass, the corrosion of the protective component 844 by the ink can be suppressed, for example, compared with the case where the protective component 844 is formed of an organic material.

[0069] As described above, the heating unit 80 of this embodiment includes a heater 84, which is a ceramic heater, and has a media drying function for drying the medium P. Furthermore, in the Z-axis direction, which is the ink ejection direction of the printhead 22 of the head unit 20, the heating unit 80 is located at least partially overlapping with the printhead 22. Since this heating unit 80 supports the medium P, it is preferably positioned near the printhead 22 with a minimum distance of less than 1 mm from the nozzle plate 320 on which the nozzle 321 (described later) of the printhead 22 is formed. That is, the minimum distance between the nozzle plate 320 and the heating unit 80 is less than 1 mm. Therefore, the medium P transported along the heating unit 80 passes near the nozzle 321 formed on the nozzle plate 320 and ejecting ink, which improves the ink's landing accuracy on the medium P.

[0070] Structure of the ejection module

[0071] Next, an example of the structure of a printhead 22 including a nozzle plate 320 having nozzles 321 will be described. Figure 4 This is an exploded perspective view showing the structure of the print head 22. Figure 5 This is a top view of the print head 22 viewed along the Z-axis. Figure 6 It is shown Figure 5 The cross-sectional view of section Bb shown. Figure 7 It is shown Figure 6 Details of the main parts, including the main part detail diagram. Figure 8 It is shown Figure 5 The cross-sectional view of section Cc shown.

[0072] like Figure 4 As shown, the printhead 22 has a pressure chamber substrate 310, a connecting plate 315, a nozzle plate 320, a flexible substrate 345, a vibrating plate 350 (described later), a piezoelectric element 60 (described later), a protective substrate 330, a housing component 340, and a wiring substrate 420.

[0073] The pressure chamber substrate 310 is composed of, for example, a silicon substrate, a glass substrate, an SOI substrate, or various ceramic substrates. Figure 5 As shown, in the pressure chamber substrate 310, two rows of pressure chambers 312 arranged along the Y-axis are configured along the X-axis. Here, the pressure chamber row located on the +X side is sometimes referred to as the first pressure chamber row, and the pressure chamber row located on the -X side of the first pressure chamber row is referred to as the second pressure chamber row. It should be noted that... Figure 5 This is a top view of the printhead 22 viewed along the Z-axis, but the peripheral structure of the pressure chamber substrate 310 is shown, while the protective substrate 330, housing component 340, etc. are omitted.

[0074] Furthermore, the multiple pressure chambers 312 constituting each pressure chamber row are arranged on a straight line along the Y-axis such that their positions along the X-axis are the same. Additionally, adjacent pressure chambers 312 along the Y-axis are... Figure 8 The partition 311 shown separates the pressure chambers. Of course, the arrangement of the pressure chambers 312 is not particularly limited. For example, the arrangement of multiple pressure chambers 312 arranged along the Y-axis can also be a so-called staggered arrangement in which the pressure chambers 312 are staggered every other one in the direction of the X-axis.

[0075] Furthermore, the pressure chamber 312 in this embodiment is formed as a rectangle, meaning its length along the X-axis is longer than its length along the Y-axis when viewed from the +Z side. Of course, the shape of the pressure chamber 312 when viewed from the +Z side is not limited to a rectangle; it can also be a parallelogram, a polygon, a circle, an ellipse, etc. Here, an ellipse refers to a shape based on a rectangle with semicircular ends along the long side, including rounded rectangular shapes, elliptical shapes, and egg shapes.

[0076] like Figure 4 As shown, a connecting plate 315, a nozzle plate 320, and a flexible substrate 345 are stacked on the +Z side of the pressure chamber substrate 310.

[0077] like Figure 4 , Figure 6 and Figure 7 As shown, a nozzle connection passage 316 connecting the pressure chamber 312 and the nozzle 321 is provided on the connecting plate 315. Additionally, a first manifold portion 317 and a second manifold portion 318, forming part of a manifold 400, are provided on the connecting plate 315. This manifold 400 serves as a common liquid chamber connected to the plurality of pressure chambers 312. The first manifold portion 317 extends through the connecting plate 315 in the Z-axis direction. The second manifold portion 318 does not extend through the connecting plate 315 in the Z-axis direction, but instead opens towards the +Z side.

[0078] Furthermore, on the connecting plate 315, a supply connecting passage 319, which connects to one end of the pressure chamber 312 in the X-axis direction, is provided independently of each pressure chamber 312. The supply connecting passage 319 connects the second manifold 318 to each pressure chamber 312 and supplies ink from the manifold 400 to each pressure chamber 312.

[0079] The connecting plate 315 can be made of silicon substrate, glass substrate, SOI substrate, various ceramic substrates, metal substrates, etc. For example, stainless steel substrate can be used as a metal substrate. It should be noted that the connecting plate 315 is preferably made of a material with a thermal expansion coefficient approximately the same as that of the pressure chamber substrate 310. Therefore, even if the temperature of the pressure chamber substrate 310 and the connecting plate 315 changes, the possibility of warping of the pressure chamber substrate 310 and the connecting plate 315 due to differences in thermal expansion coefficients can be reduced.

[0080] The nozzle plate 320 is disposed on the opposite side of the pressure chamber base plate 310 of the connecting plate 315, i.e., the +Z side. Nozzles 321 are formed on the nozzle plate 320 and communicate with each pressure chamber 312 via nozzle connecting passages 316.

[0081] In this embodiment, the printhead 22 has a plurality of nozzles 321 arranged along the Y-axis. Specifically, on the nozzle plate 320, two rows of nozzles 321 arranged side-by-side are separated along the X-axis. These two rows of nozzles correspond to the first pressure chamber row and the second pressure chamber row, respectively. Furthermore, the plurality of nozzles 321 in each row are arranged in the same position along the X-axis. It should be noted that the arrangement of the nozzles 321 is not particularly limited; for example, the nozzles 321 arranged along the Y-axis may be arranged at positions offset along the X-axis, with every other nozzle being arranged at a position staggered.

[0082] The material of the nozzle plate 320 is not particularly limited; for example, silicon substrates, glass substrates, SOI substrates, various ceramic substrates, and metal substrates can be used. Furthermore, stainless steel substrates are an example of metal substrates. Additionally, organic materials such as polyimide resin can also be used as the material of the nozzle plate 320. Preferably, the nozzle plate 320 is made of a material with approximately the same coefficient of thermal expansion as the connecting plate 315. This reduces the possibility of warping of the nozzle plate 320 and the connecting plate 315 due to differences in their coefficients of thermal expansion, even when the temperatures of the nozzle plate 320 and the connecting plate 315 change.

[0083] The flexible substrate 345, together with the nozzle plate 320, is disposed on the opposite side of the pressure chamber substrate 310 of the connecting plate 315, i.e., the +Z side. The flexible substrate 345, disposed around the nozzle plate 320, seals the openings of the first manifold portion 317 and the second manifold portion 318 disposed on the connecting plate 315. The flexible substrate 345 includes a sealing film 346 made of a flexible thin film and a fixing substrate 347 made of a rigid material such as metal. Furthermore, the area of ​​the fixing substrate 347 opposite the manifold 400 becomes an opening 348 that is completely removed in the thickness direction. Therefore, one side of the manifold 400 becomes a flexible portion 349 sealed only by the flexible sealing film 346.

[0084] On the other hand, a vibrating plate 350 and a piezoelectric element 60 are stacked on the surface opposite to the nozzle plate 320, i.e., on the -Z side, of the pressure chamber substrate 310. The vibrating plate 350 is flexed and deformed to cause pressure changes in the ink within the pressure chamber 312. In other words, the vibrating plate 350 is positioned relative to the piezoelectric element 60 on the +Z side along the Z-axis, and the pressure chamber substrate 310 is positioned relative to the vibrating plate 350 on the +Z side along the Z-axis. It should be noted that... Figure 6 This diagram illustrates the overall structure of the printhead 22, simplifying the structure of the piezoelectric element 60.

[0085] Furthermore, a protective substrate 330 having approximately the same size as the pressure chamber substrate 310 is bonded to the -Z side surface of the pressure chamber substrate 310 using an adhesive or the like. The protective substrate 330 has a holding portion 331 that serves as a space for protecting the piezoelectric elements 60. The holding portion 331 is a space independently provided for each row of piezoelectric elements 60 arranged in the Y-axis direction, and two are formed in the X-axis direction. Additionally, a through hole 332 extending in the Z-axis direction is provided between the two holding portions 331 arranged in the X-axis direction on the protective substrate 330.

[0086] Additionally, a housing component 340 is fixed on the protective substrate 330, which, together with the pressure chamber substrate 310, divides the manifold 400 communicating with the plurality of pressure chambers 312. The housing component 340 has a shape substantially the same as the aforementioned connecting plate 315 when viewed from the -Z side, and is engaged with both the protective substrate 330 and the aforementioned connecting plate 315.

[0087] Such a housing component 340 has a receiving portion 341 on the protective substrate 330 side. This receiving portion 341 is a space with a depth capable of accommodating the pressure chamber substrate 310 and the protective substrate 330. The receiving portion 341 has an opening area larger than the surface of the protective substrate 330 that engages with the pressure chamber substrate 310. Furthermore, when the pressure chamber substrate 310 and the protective substrate 330 are accommodated in the receiving portion 341, the opening surface on the nozzle plate 320 side of the receiving portion 341 is sealed by the connecting plate 315.

[0088] Furthermore, third manifold sections 342 are respectively divided on both outer sides of the receiving portion 341 in the X-axis direction of the housing component 340. Additionally, the manifold 400 is formed by the first manifold section 317, the second manifold section 318, and the third manifold section 342 provided on the connecting plate 315. The manifold 400 is continuously arranged in the Y-axis direction, and the supply connecting passages 319 connecting each pressure chamber 312 to the manifold 400 are arranged in the Y-axis direction.

[0089] Additionally, a supply port 344 is provided on the housing component 340 for communicating with the manifold 400 and supplying ink to each manifold 400. Furthermore, a connection port 343 is provided on the housing component 340 for communicating with the through hole 332 of the protective substrate 330 and for inserting the wiring substrate 420.

[0090] In this first embodiment, the printhead 22 receives ink stored in the ink container 90 from the supply port 344. After the manifold 400 is filled with this ink to the nozzle 321, a signal based on the drive signal COM is supplied from the integrated circuit 421 to each piezoelectric element 60 corresponding to the pressure chamber 312. As a result, the vibrating plate 350 flexes and deforms together with the piezoelectric elements 60, increasing the pressure within each pressure chamber 312 and ejecting ink from each nozzle 321.

[0091] Next, the configuration including the aforementioned vibrating plate 350 and piezoelectric element 60, which is stacked on the -Z side of the pressure chamber substrate 310, will be described. As a configuration stacked on the -Z side of the pressure chamber substrate 310, in addition to the vibrating plate 350 and piezoelectric element 60, the printhead 22 also has a single lead electrode 391, a common lead electrode 392, a measurement lead electrode 393, and a resistor wiring 401.

[0092] like Figures 6-8As shown, the vibrating plate 350 comprises an elastic film 351 made of silicon oxide disposed on the pressure chamber substrate 310 side, and an insulating film 352 made of zirconium oxide disposed on the elastic film 351. The liquid flow channels of the pressure chamber 312, etc., are formed by anisotropic etching from the +Z side surface of the pressure chamber substrate 310, and the -Z side surface of the liquid flow channels of the pressure chamber 312, etc., is composed of the elastic film 351. It should be noted that the composition of the vibrating plate 350 is not particularly limited; for example, it may be composed of either the elastic film 351 or the insulating film 352, and furthermore, it may include other films besides the elastic film 351 and the insulating film 352. Examples of materials for other films constituting the vibrating plate 350 include silicon and silicon nitride.

[0093] The piezoelectric element 60 functions as a piezoelectric actuator that causes pressure changes in the ink within the pressure chamber 312. This piezoelectric element 60 has electrodes 360, a piezoelectric body 370, and an electrode 380 stacked sequentially from the vibrating plate 350 side (+Z side) to the -Z side. In other words, the piezoelectric element 60 includes electrodes 360, 380, and a piezoelectric body 370, with the piezoelectric body 370 disposed between electrodes 360 and 380 in the Z-axis direction where the electrodes 360, 380, and 370 are stacked.

[0094] Electrodes 360 and 380 are both electrically connected to the wiring substrate 420. Furthermore, a signal supplied from the integrated circuit 421 mounted on the wiring substrate 420 is supplied to electrode 360, and a reference potential signal propagating in the wiring substrate 420 is supplied to electrode 380. Thus, the signal supplied from the integrated circuit 421 and the reference potential signal are supplied to the piezoelectric element 370. Additionally, the piezoelectric element 370 deforms due to the potential difference generated between electrodes 360 and 380. This deformation of the piezoelectric element 370 causes the vibrating plate 350 to deform or vibrate, resulting in a change in the volume of the pressure chamber 312. Furthermore, the pressure change caused by the change in the volume of the pressure chamber 312 is applied to the ink contained in the pressure chamber 312, causing the ink contained in the pressure chamber 312 to be ejected from the nozzle 321 via the nozzle connection 316. At this time, the amount of ink ejected from the nozzle 321 is equal to the change in the volume of the pressure chamber 312.

[0095] In the following description, the portion of the piezoelectric element 60 that generates piezoelectric strain in the piezoelectric body 370 when a voltage is applied between electrodes 360 and 380 is referred to as the active portion 410, and the portion of the piezoelectric body 370 that does not generate piezoelectric strain is referred to as the inactive portion 415. That is, the portion of the piezoelectric element 60 where the piezoelectric body 370 is sandwiched between electrodes 360 and 380 corresponds to the active portion 410, and the portion of the piezoelectric body 370 not sandwiched between electrodes 360 and 380 corresponds to the inactive portion 415. Furthermore, when the piezoelectric element 60 is driven, the portion that displaces in the Z-axis direction is referred to as the flexible portion, and the portion that does not displace in the Z-axis direction is referred to as the non-flexible portion. That is, the portion of the piezoelectric element 60 opposite the pressure chamber 312 in the Z-axis direction corresponds to the flexible portion, and the outer portion of the pressure chamber 312 corresponds to the non-flexible portion. It should be noted that the active part 410 is sometimes referred to as the active part, and the inactive part 415 is sometimes referred to as the passive part.

[0096] Generally, each electrode of the active part 410 is configured as a single electrode independent for each active part 410, and the other electrode is configured as a common electrode shared by multiple active parts 410. In this embodiment, the electrode 360, which supplies the signal output by the integrated circuit 421, is configured as a single electrode, and the electrode 380, which supplies the signal of the reference potential propagating in the wiring substrate 420, is configured as a common electrode.

[0097] Specifically, the electrode 360 ​​is disposed on the +Z side relative to the piezoelectric element 370, forming a single electrode that is divided for each pressure chamber 312 and independent for each active part 410. That is, the electrode 360 ​​is disposed individually relative to the plurality of pressure chambers 312. In the direction along the Y-axis, the electrode 360 ​​is formed with a width narrower than the width of the pressure chamber 312. That is, in the direction along the Y-axis, the end of the electrode 360 ​​is located inside the region opposite to the pressure chamber 312.

[0098] Furthermore, the +X side end 360a and the -X side end 360b of the electrode 360 ​​are respectively disposed on the outside of the pressure chamber 312. For example, in the first pressure chamber row, such as Figure 7 As shown, end 360a of electrode 360 ​​is positioned further to the +X side than end 312a on the +X side of pressure chamber 312. End 360b of electrode 360 ​​is positioned further to the -X side than end 312b on the -X side of pressure chamber 312.

[0099] The material of electrode 360 ​​is not particularly limited; for example, conductive materials such as metals like platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti), or conductive metal oxides such as indium tin oxide (ITO) can be used. Alternatively, multiple materials such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti) can be layered to form the electrode. In the first embodiment, platinum (Pt) is used as electrode 360.

[0100] like Figure 5 As shown, the piezoelectric element 370 has a predetermined length along the X-axis and is continuously arranged along the Y-axis. That is, the piezoelectric element 370 is continuously arranged with a predetermined thickness along the side-by-side arrangement direction of the pressure chamber 312. The thickness of the piezoelectric element 370 is not particularly limited and is formed with a thickness of about 1000 nanometers to 4000 nanometers.

[0101] In addition, such as Figure 7 As shown, the length of the piezoelectric element 370 along the X-axis is longer than the length of the pressure chamber 312 along the X-axis, which is its longer side. Therefore, the piezoelectric element 370 extends to the outside of the pressure chamber 312 on both sides along the X-axis. By extending the piezoelectric element 370 to the outside of the pressure chamber 312 along the X-axis, the strength of the vibrating plate 350 is increased. Therefore, when the piezoelectric element 60 is displaced by driving the active part 410, the possibility of cracks or other defects in the vibrating plate 350 or the piezoelectric element 60 can be reduced.

[0102] Additionally, for example, in the first pressure chamber row, such as Figure 7 As shown, the +X side end 370a of the piezoelectric body 370 is located on the +X side further outward than the end 360a of the electrode 360. That is, the end 360a of the electrode 360 ​​is covered by the piezoelectric body 370. On the other hand, the -X side end 370b of the piezoelectric body 370 is located on the +X side further inward than the end 360b of the electrode 360, and the end 360b of the electrode 360 ​​is not covered by the piezoelectric body 370.

[0103] It should be noted that, as Figure 5 and Figure 8 As shown, grooves 371, which are thinner than other regions, are formed on the piezoelectric body 370 corresponding to each partition 311. In this embodiment, the grooves 371 are formed by completely removing the piezoelectric body 370 in the Z-axis direction. That is, the piezoelectric body 370 having a thinner thickness than other regions means that the piezoelectric body 370 is completely removed in the Z-axis direction. Of course, the piezoelectric body 370 can also be formed thinner than other regions on the bottom surface of the grooves 371.

[0104] Furthermore, the length of the groove 371 along the Y-axis, i.e., the width of the groove 371, is the same as or wider than the width of the partition 311. In this embodiment, the width of the groove 371 is wider than the width of the partition 311. When viewed from the -Z side, such a groove 371 is rectangular. Of course, the shape of the groove 371 when viewed from the -Z side is not limited to a rectangular shape; it can also be a polygon with more than one pentagon, or a circular or elliptical shape, etc.

[0105] By providing a groove 371 on the piezoelectric element 370, the rigidity of the portion of the vibrating plate 350 that is opposite to the end of the pressure chamber 312 in the Y-axis direction, i.e., the arm portion of the vibrating plate 350, can be suppressed, thus enabling the piezoelectric element 60 to be displaced more effectively.

[0106] Examples of piezoelectric materials 370 include perovskite-structured crystal films formed on electrodes 360, which are composed of ferroelectric ceramic materials representing electromechanical conversion. Materials used for the piezoelectric material 370 include, for example, ferroelectric piezoelectric materials such as lead zirconate titanate (PZT), and materials to which metal oxides such as niobium oxide, nickel oxide, or magnesium oxide have been added. Specifically, lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), lead zirconate (PbZrO3), lanthanum lead titanate ((Pb,La),TiO3), lanthanum lead zirconate titanate ((Pb,La)(Zr,Ti)O3), or lead magnesium zirconate titanate (Pb(Zr,Ti)(Mg,Nb)O3) can be used. In this embodiment, lead zirconate titanate (PZT) is used as the piezoelectric material 370.

[0107] Furthermore, the material used for the piezoelectric element 370 is not limited to lead-based piezoelectric materials containing lead; lead-free non-lead piezoelectric materials can also be used. Examples of lead-free piezoelectric materials include bismuth ferrite ((BiFeO3, abbreviated as "BFO")), barium titanate ((BaTiO3, abbreviated as "BT")), potassium sodium niobate ((K,Na)(NbO3, abbreviated as "KNN")), lithium potassium sodium niobate ((K,Na,Li)(NbO3)), lithium potassium sodium niobate ((K,Na,Li)(Nb,Ta)O3), potassium bismuth potassium titanate ((Bi1 / 2K1 / 2)TiO3, abbreviated as "BKT"), sodium bismuth titanate ((Bi1 / 2Na1 / 2)TiO3, abbreviated as "BNT"), and bismuth manganate (…). BiMnO3 (abbreviated as "BM"), composite oxides containing bismuth, potassium, titanium and iron with a perovskite structure (x[(BixK1-x)TiO3]-(1-x)[BiFeO3], abbreviated as "BKT-BF"), composite oxides containing bismuth, iron, barium and titanium with a perovskite structure ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), and materials with added manganese, cobalt, chromium and other metals ((1-x)[Bi(Fe1-yMy)O3]-x[BaTiO3] (M is Mn, Co or Cr)), etc.

[0108] like Figure 5 , Figure 7 and Figure 8 As shown, electrode 380 is disposed on the -Z side opposite to electrode 360, relative to piezoelectric body 370, forming a common electrode shared by multiple active parts 410. That is, electrode 380 is disposed for multiple pressure chambers 312. Electrode 380 is disposed with a predetermined length along the X-axis and is continuously disposed along the Y-axis. Electrode 380 is also disposed on the inner surface of groove 371, i.e., on the side surface of groove 371 of piezoelectric body 370 and on insulating film 352 which is the bottom surface of groove 371. It should be noted that, regarding the groove 371, electrode 380 may be disposed only on a portion of the inner surface of groove 371, or may not be disposed on the entire inner surface of groove 371.

[0109] Additionally, for example, in the first pressure chamber row, such as Figure 7As shown, the +X side end 380a of electrode 380 is positioned further outward than the end 360a of electrode 360 ​​covered by piezoelectric body 370. That is, the end 380a of electrode 380 is located on the +X side further outward than the end 312a of pressure chamber 312, and also on the +X side further outward than the end 360a of electrode 360. In this embodiment, the end 380a of electrode 380 substantially coincides with the end 370a of piezoelectric body 370 in the X-axis direction. Therefore, the +X side end of active portion 410, i.e., the boundary between active portion 410 and inactive portion 415, is defined by the end 360a of electrode 360.

[0110] On the other hand, the -X side end 380b of electrode 380 is disposed on the -X side, which is further outward than the -X side end 312b of pressure chamber 312, and further inward than the end 370b of piezoelectric body 370. As described above, the end 370b of piezoelectric body 370 is located on the inner side, which is further inward than the end 360b of electrode 360. Therefore, the end 380b of electrode 380 is located on piezoelectric body 370, which is further inward than the end 360b of electrode 360. Therefore, on the -X side of end 380b of electrode 380, there is a portion of the surface of piezoelectric body 370 exposed.

[0111] In this way, the end 380b of electrode 380 is positioned further towards the +X side than the end 370b of piezoelectric body 370 and the end 360b of electrode 360. Therefore, the end of active part 410 on the -X side, that is, the boundary between active part 410 and inactive part 415, is defined by the end 380b of electrode 380.

[0112] The material of electrode 380 is not particularly limited, but similar to electrode 360, it can be a conductive material such as metals like platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti), or conductive metal oxides such as indium tin oxide (ITO). Alternatively, it can be formed by layering multiple materials such as platinum (Pt), iridium (Ir), gold (Au), and titanium (Ti). In this embodiment, iridium (Ir) is used as electrode 380.

[0113] Furthermore, on the outer side of the end 380b of the electrode 380, that is, further towards the -X side of the end 380b of the electrode 380, a wiring portion 385 is provided, which is in the same layer as the electrode 380 but electrically discontinuous with the electrode 380. The wiring portion 385 is formed from the piezoelectric body 370 to the electrode 360, leaving a gap so as not to contact the end 380b of the electrode 380. The electrode 360 ​​extends further towards the -X side than the piezoelectric body 370. This wiring portion 385 is provided independently for each active portion 410. That is, multiple wiring portions 385 are arranged at predetermined intervals along the Y-axis. It should be noted that the wiring portion 385 may also be formed from a different layer than the electrode 380, but it is preferable that it is formed from the same layer as the electrode 380. This simplifies the manufacturing process of the wiring portion 385 and reduces costs.

[0114] Furthermore, on the electrodes 360 and 380 constituting the piezoelectric element 60, a single lead electrode 391 is connected to the electrode 360, and a common lead electrode 392 serving as a common driving electrode is electrically connected to the electrode 380. A flexible wiring substrate 420 is electrically connected to the ends of the single lead electrode 391 and the common lead electrode 392 opposite to the ends connected to the piezoelectric element 60. Multiple wirings for connecting to the control unit 10, the temperature information output circuit 26, and multiple circuits (not shown) are formed on the wiring substrate 420. In this embodiment, the wiring substrate 420 is, for example, constructed from an FPC (Flexible Printed Circuit). It should be noted that an FPC can be used instead of an FPC, and any flexible substrate such as an FFC (Flexible Flat Cable) can be used.

[0115] In this embodiment, the individual lead electrode 391 and the common lead electrode 392 extend and are exposed within a through-hole 332 formed in the protective substrate 330, and are electrically connected to the wiring substrate 420 within the through-hole 332. Additionally, an integrated circuit 421 for outputting signals for driving the piezoelectric element 60 is mounted on the wiring substrate 420.

[0116] In this embodiment, the individual lead electrode 391 and the common lead electrode 392 are formed from the same layer, but are electrically discontinuous. Therefore, compared to forming the individual lead electrode 391 and the common lead electrode 392 separately, the manufacturing process can be simplified and costs reduced. Of course, the individual lead electrode 391 and the common lead electrode 392 can also be formed from different layers.

[0117] The materials used for the individual lead electrode 391 and the common lead electrode 392 are not particularly limited, as long as they are conductive. For example, gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), and aluminum (Al) can be used. In this embodiment, gold (Au) is used as both the individual lead electrode 391 and the common lead electrode 392. Furthermore, the individual lead electrode 391 and the common lead electrode 392 may also have an adhesive layer that improves adhesion to the electrode 360, the electrode 380, or the vibrating plate 350.

[0118] Each lead electrode 391 is provided for each active part 410, i.e., each electrode 360. For example... Figure 7 As shown, for example, in the first pressure chamber array, a single lead electrode 391 is connected via a wiring portion 385 to the vicinity of the end 360b of the electrode 360 ​​disposed on the outside of the piezoelectric body 370, and is led out in the -X direction to the pressure chamber substrate 310, which is actually the vibrating plate 350.

[0119] On the other hand, such as Figure 5 As shown, for example, in the first pressure chamber array, at both ends along the Y-axis, a common lead electrode 392 extends from the electrode 380 constituting the common electrode on the piezoelectric body 370 toward the -X side to the vibrating plate 350. Furthermore, the common lead electrode 392 has an extension portion 392a and an extension portion 392b. (As shown...) Figure 5 , Figure 7 As shown, for example, in the first pressure chamber row, the extension portion 392a extends along the Y-axis in the region corresponding to the end 312a of the pressure chamber 312, and the extension portion 392b extends along the Y-axis in the region corresponding to the end 312b of the pressure chamber 312. These extension portions 392a and 392b are continuously arranged relative to the plurality of active portions 410 in the Y-axis direction.

[0120] Furthermore, the extension portions 392a and 392b extend from the inside of the pressure chamber 312 to the outside of the pressure chamber 312 in the X-axis direction. In this embodiment, the active portion 410 of the piezoelectric element 60 extends to the outside of the pressure chamber 312 at both ends in the X-axis direction, and the extension portions 392a and 392b extend from the active portion 410 to the outside of the pressure chamber 312.

[0121] like Figure 7As shown, a resistance wire 401 is provided on the -Z side surface of the vibrating plate 350. The resistance wire 401 detects the temperature of the pressure chamber 312 by utilizing the characteristic that the resistance value changes with temperature. The material of such a resistance wire 401 is a material whose resistance value is temperature-dependent, such as gold (Au), platinum (Pt), iridium (Ir), aluminum (Al), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), etc. Among these, platinum (Pt) exhibits a large temperature-dependent resistance value change, and also has high stability and accuracy. Furthermore, platinum (Pt) shows a high linearity in its resistance value change with temperature. From this viewpoint, platinum (Pt) is preferably used as the material for the resistance wire 401. That is, it is preferable that the resistance wire 401 is constructed containing platinum (Pt). In this embodiment, the resistance wire 401 is formed on the -Z side surface of the vibrating plate 350 in a manner that is co-layered with and electrically discontinuous with the electrode 360. That is, the resistor wiring 401 has wiring disposed on the -Z side of the vibrating plate 350 in the direction of Z-axis and containing platinum (Pt).

[0122] like Figure 5 As shown, one end of the resistor wiring 401 is connected to the measuring lead electrode 393a, and the other end of the resistor wiring 401 is connected to the measuring lead electrode 393b. Furthermore, the measuring lead electrodes 393a and 393b are electrically connected to the wiring substrate 420. Thus, a voltage signal corresponding to the resistance value is output from the printhead 22, and this resistance value varies according to the temperature of the pressure chamber 312 detected by the resistor wiring 401. In this embodiment, the resistor wiring 401 is covered by a piezoelectric element 370 and is located between the vibrating plate 350 and the piezoelectric element 370 in the Z-axis direction.

[0123] The resistor wiring 401 includes a first pressure chamber row side serpentine pattern located on the +X side along the X-axis and a second pressure chamber row side serpentine pattern located on the -X side along the X-axis. Viewed from the -Z side, the first pressure chamber row side serpentine pattern is located at a position overlapping with the supply connection path 319, serpentine along the Y-axis, and the supply connection path 319 communicates with each pressure chamber 312 constituting the first pressure chamber row. Viewed from the -Z side, the second pressure chamber row side serpentine pattern is located at a position overlapping with the supply connection path 319, serpentine along the Y-axis, and the supply connection path 319 communicates with each pressure chamber 312 constituting the second pressure chamber row. That is, the resistor wiring 401 has a first pressure chamber row side serpentine pattern corresponding to the first pressure chamber row formed by the plurality of pressure chambers 312, and a second pressure chamber row side serpentine pattern corresponding to the second pressure chamber row formed by the plurality of pressure chambers 312.

[0124] In addition, such as Figure 6 , Figure 7 As shown, the distance between the -Z side end of pressure chamber 312 and the resistor wiring 401 along the Z-axis is shorter than the dimension of pressure chamber 312 along the Z-axis. Furthermore, for example, in the first pressure chamber row, the longest distance between the +X side end 312a of pressure chamber 312 and the resistor wiring 401 along the X-axis is shorter than the dimension of pressure chamber 312 along the X-axis. Therefore, the resistance value of resistor wiring 401 easily changes in response to temperature changes in pressure chamber 312.

[0125] In this embodiment, the measuring lead electrode 393, including measuring lead electrode 393a and measuring lead electrode 393b, is formed in the same layer as the individual lead electrode 391 and the common lead electrode 392, but is electrically discontinuous. Therefore, compared to forming the measuring lead electrode 393, the individual lead electrode 391, and the common lead electrode 392 individually, the manufacturing process can be simplified and costs reduced. Of course, the measuring lead electrode 393 can also be formed from a different layer than the individual lead electrode 391 and the common lead electrode 392.

[0126] The material of the 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), chromium (Cr), platinum (Pt), and aluminum (Al) can be used. In this embodiment, gold (Au) is used as the measuring lead electrode 393. Therefore, the material of the measuring lead electrode 393 is the same as that of the individual lead electrode 391 and the common lead electrode 392. In addition, the measuring lead electrode 393 may also have an adhesive layer to improve adhesion to the resistance wiring 401 or the oscillating plate 350.

[0127] As described above, in this embodiment, the measuring lead electrode 393 extends and protrudes into the through-hole 332 formed in the protective substrate 330, and is electrically connected to the wiring substrate 420 within the through-hole 332. Thus, the resistance value of the resistive wiring 401, which varies according to the temperature of the pressure chamber 312, is output from the printhead 22 via the wiring substrate 420.

[0128] That is, the printhead 22 of the printhead unit 20 in this embodiment includes: a piezoelectric element 60, including electrodes 360, 380 and piezoelectric body 370, with the piezoelectric body 370 located between electrodes 360 and 380 in the Z-axis direction where electrodes 360, 380 and piezoelectric body 370 are stacked, and is driven by a drive signal COM; a vibrating plate 350, located on the +Z side of the Z-axis direction relative to the piezoelectric element 60, and deformed by the drive of the piezoelectric element 60; a pressure chamber substrate 310, located on the +Z side of the Z-axis direction relative to the vibrating plate 350, and provided with a pressure chamber 312 whose volume changes according to the deformation of the vibrating plate 350; a nozzle 321, which ejects ink according to the change in volume of the pressure chamber 312; and a resistor wiring 401, located on the -Z side of the Z-axis direction relative to the vibrating plate 350, and obtains a temperature corresponding to the temperature of the pressure chamber 312.

[0129] 2. Functional Composition of Liquid Ejection Device

[0130] Functional composition of liquid ejection device

[0131] Next, the functional configuration of the liquid ejection device 1 will be explained. Figure 9 This is a diagram showing the functional configuration of the liquid ejection device 1. (See diagram below.) Figure 9 As shown, the liquid ejection device 1 includes a control unit 10, a head unit 20, a carriage motor 31, a conveyor motor 41, a heater 84, and a linear encoder 92.

[0132] The control unit 10 includes a drive circuit 50, a reference voltage output circuit 52, and a control circuit 100. The control circuit 100 includes, for example, processing circuits such as a CPU or FPGA, and storage circuits such as semiconductor memory. Image information signals, including image data, are input to the control circuit 100 from external devices such as a host computer that are communicatively connected to the liquid ejection device 1. Based on the input image information signals, the control circuit 100 generates various signals for controlling the liquid ejection device 1 and outputs them to the corresponding components.

[0133] As a specific example, in the control circuit 100, in addition to the aforementioned image information signal, a detection signal based on the scanning position of the carriage 21 included in the head unit 20 is also input from the linear encoder 92. Thus, the control circuit 100 determines the scanning position of the carriage 21, that is, the scanning position of the head unit 20 including the print head 22. Furthermore, the control circuit 100 generates various signals corresponding to the input image information signal and the determined scanning position of the head unit 20, and outputs them to the corresponding components.

[0134] In detail, the control circuit 100 generates a control signal Ctrl-C for controlling the movement of the head unit 20 along the scanning axis based on the scanning position of the head unit 20, and outputs it to the carriage motor 31. As a result, the carriage motor 31 operates, controlling the movement and scanning position of the head unit 20 mounted on the carriage 21 along the scanning axis. Additionally, the control circuit 100 generates a control signal Ctrl-T for controlling the transport of the medium P, and outputs it to the transport motor 41. As a result, the transport motor 41 operates, controlling the movement of the medium P along the transport direction. It should be noted that the control signal Ctrl-C can also be input to the carriage motor 31 after signal conversion via a driver circuit (not shown), and the control signal Ctrl-T can also be input to the transport motor 41 after signal conversion via a driver circuit (not shown).

[0135] Furthermore, the control circuit 100 generates a control signal Ctrl-W for controlling the temperature of the heater 84 based on the type of ink being sprayed, the type of medium P to which the ink lands, and the operating state of the liquid spraying device 1, and outputs this signal to the heater 84. Thus, the heater 84 is controlled to the desired temperature. At this time, the control circuit 100 can output a pre-defined current value, voltage value, or current value corresponding to the temperature of the heater 84 as the control signal Ctrl-W. Alternatively, it can output a control signal Ctrl-W indicating the temperature of the heater 84 to a heater control circuit (not shown) that controls the temperature of the heater 84.

[0136] Furthermore, based on the image information signal input from the external device and the scanning position of the head unit 20, the control circuit 100 generates printing data signals SI1 to SIn, a change signal CH, a latch signal LAT, and a clock signal SCK as the control signal Ctrl-H for controlling the head unit 20, and outputs them to the head unit 20. Additionally, the control circuit 100 generates a temperature acquisition request signal TD at a predetermined timing to acquire the temperature of the head unit 20, and outputs it to the head unit 20. At this time, a temperature information signal TI, which includes the temperature of the head unit 20 corresponding to the temperature acquisition request signal TD, is input to the control circuit 100. Based on the input temperature information signal TI, the control circuit 100 monitors the state of the head unit 20, corrects the control signals Ctrl-H, Ctrl-C, and Ctrl-T, and outputs them to the corresponding components.

[0137] Then, the control circuit 100 outputs a base drive signal dA1 as a digital signal to the drive circuit 50. The drive circuit 50 generates a drive signal COM with a signal waveform defined by the base drive signal dA1 as the drive signal COM, and outputs it to the head unit 20.

[0138] Specifically, the base drive signal dA1 output by the control circuit 100 is input to the drive circuit 50. After converting the input base drive signal dA1 into a digital-to-analog signal, the drive circuit 50 generates a drive signal COM by performing Class D amplification on the converted analog signal and outputs it to the head unit 20. Here, the base drive signal dA1 output by the control circuit 100 is described as a digital signal that defines the signal waveform of the drive signal COM. However, the base drive signal dA1 can be any signal that defines the signal waveform of the drive signal COM, and it can also be an analog signal. In addition, the drive circuit 50 can also generate the drive signal COM by performing Class A amplification, Class B amplification, or Class AB amplification on the signal waveform defined by the base drive signal dA1.

[0139] 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 constant potential signal that serves as a reference for driving the piezoelectric element 60 and is supplied to the electrode 380, which serves as a common electrode. Such a reference voltage signal VBS can be, for example, a constant signal at ground potential, or a constant DC voltage signal at potentials such as 5.5V or 6V.

[0140] The head unit 20 includes printheads 22-1 to 22-n, which are multiple printheads 22, a temperature information output circuit 26, and a temperature detection circuit 28. In addition, printheads 22-1 to 22-n each include a drive signal selection circuit 200, a temperature detection circuit 24, and multiple piezoelectric elements 60.

[0141] The print head 22-1 receives the print data signal SI1, change signal CH, latch signal LAT, clock signal SCK, drive signal COM, and reference voltage signal VBS output from the control circuit 100. The clock signal SCK, latch signal LAT, change signal CH, print data signal SI1, and drive signal COM input to the print head 22-1 are then input to the drive signal selection circuit 200. Based on the input clock signal SCK, latch signal LAT, change signal CH, and print data signal SI1, the drive signal selection circuit 200 generates drive signals VOUT corresponding to the multiple piezoelectric elements 60 by selecting or not selecting the signal waveforms included in the drive signal COM. Furthermore, the drive signal selection circuit 200 outputs the generated drive signals VOUT to one end of each corresponding piezoelectric element 60, i.e., electrode 360, which serves as a single electrode. Additionally, the reference voltage signal VBS is input to the other end of the multiple piezoelectric elements 60, i.e., electrode 380, which serves as a common electrode. Furthermore, the multiple piezoelectric elements 60 are displaced by the potential difference between the drive signal VOUT input to the electrode 360 ​​and the reference voltage signal VBS input to the electrode 380. Consequently, an amount of ink corresponding to the displacement of the piezoelectric elements 60 is ejected from the corresponding nozzles 321 of the printhead 22-1. Here, at least a portion of the drive signal selection circuit 200 of the printhead 22-1 is mounted as the aforementioned integrated circuit 421 on the wiring substrate 420 of the printhead 22-1.

[0142] Furthermore, the temperature detection circuit 24 of the printhead 22-1 detects the temperature of the printhead 22-1. The temperature detection circuit 24 acquires the detected temperature of the printhead 22-1 as printhead temperature information tc1, and outputs a printhead temperature signal TC1 including the acquired printhead temperature information tc1 to the temperature information output circuit 26. Here, at least a portion of the temperature detection circuit 24 of the printhead 22-1 is provided in the printhead 22-1 as the aforementioned resistor wiring 401. That is, the printhead temperature information tc1, representing the temperature of the printhead 22-1 output by the temperature detection circuit 24, includes information about the voltage value generated based on the resistance value of the resistor wiring 401.

[0143] Furthermore, printheads 22-2 to 22-n differ only in the input and output signals, performing the same operations as printhead 22-1. Specifically, a clock signal SCK, a latch signal LAT, a change signal CH, a print data signal SIi, a drive signal COM, and a reference voltage signal VBS are input to printhead 22-i (i being any one of 2 to n). Additionally, the drive signal selection circuit 200 of printhead 22-i, based on the input clock signal SCK, latch signal LAT, change signal CH, and print data signal SIi, generates drive signals VOUT corresponding to the plurality of piezoelectric elements 60 by selecting or not selecting the signal waveform of the drive signal COM, and outputs these signals to the electrodes 360 of the corresponding piezoelectric elements 60. Furthermore, the reference voltage signal VBS is input to the electrodes 380 of the plurality of piezoelectric elements 60 in printhead 22-i. Therefore, the multiple piezoelectric elements 60 of the printhead 22-i are driven, and an amount of ink corresponding to the driving of the piezoelectric elements 60 is ejected from the nozzle 321 of the printhead 22-i. Additionally, the temperature detection circuit 24 of the printhead 22-i acquires the temperature of the printhead 22-i as printhead temperature information tci, and outputs a printhead temperature signal TCi including the acquired printhead temperature information tci to the temperature information output circuit 26. Here, at least a portion of the drive signal selection circuit 200 of the printhead 22-i is mounted as the aforementioned integrated circuit 421 on the wiring substrate 420 of the printhead 22-i, and at least a portion of the temperature detection circuit 24 of the printhead 22-i is provided as the aforementioned resistive wiring 401 on the printhead 22-i.

[0144] Here, in the following description, we will explain the process of inputting a clock signal SCK, a latch signal LAT, a change signal CH, print data signals SI (as print data signals SI1 to SIn), a drive signal COM, and a reference voltage signal VBS to the print head 22 when there is no need to distinguish between print heads 22-1 to 22-n. Furthermore, we will explain the process of the print head 22's temperature detection circuit 24 acquiring print temperature information tc (as print temperature information tc1 to tcn) representing the temperature of the print head 22, and the print head 22 outputting print temperature signals TC (as print temperature signals TC1 to TCn) including the acquired print temperature information tc.

[0145] Temperature detection circuit 28 detects the temperature of the printhead units 20, including printheads 22-1 to 22-n. Furthermore, temperature detection circuit 28 generates a unit temperature signal TH, which includes unit temperature information th representing the detected temperature. Temperature detection circuit 28 outputs the generated unit temperature signal TH to temperature information output circuit 26 and control circuit 100. This temperature detection circuit 28 is configured including a thermistor element, the resistance of which changes according to the temperature change of the printhead units 20.

[0146] The temperature information output circuit 26 receives the printhead temperature signals TC1 to TCn output by printheads 22-1 to 22-n, the unit temperature signal TH output by temperature detection circuit 28, and the temperature acquisition request signal TD output by control circuit 100. The temperature information output circuit 26 amplifies and holds the input printhead temperature signals TC1 to TCn, and also amplifies and holds the unit temperature signal TH. Furthermore, the temperature information output circuit 26 calculates a correction function based on the held printhead temperature signals TC1 to TCn and the unit temperature signal TH.

[0147] Then, the temperature information output circuit 26 acquires the head temperature information tc1 to tcn included in the input head temperature signals TC1 to TCn based on the temperature acquisition request signal TD input from the control circuit 100, and corrects the temperature specified by the acquired head temperature information tc1 to tcn using a calculated correction function. Furthermore, the temperature information output circuit 26 outputs the corrected temperature information signal TI to the control circuit 100. It should be noted that a specific example of the configuration and operation of the temperature information output circuit 26 will be described later.

[0148] As described above, the liquid ejection device 1 of this embodiment includes: a control circuit 100 that outputs a control signal Ctrl-H including a clock signal SCK, a latch signal LAT, a change signal CH, and a printing data signal SI; a drive circuit 50 that outputs a drive signal COM; and a head unit 20 that receives the control signal Ctrl-H and the drive signal COM to eject ink, and has: a print head 22 that ejects liquid based on a drive signal VOUT corresponding to the drive signal COM; a temperature detection circuit 28 that detects the temperature of the head unit 20 as unit temperature information th and outputs a unit temperature signal TH including the unit temperature information th; and a temperature information output circuit 26 that receives the unit temperature signal TH and a head temperature signal TC including head temperature information tc corresponding to the temperature of the print head 22, and outputs a temperature information signal TI.

[0149] The signal waveform of the drive signal COM and the functional composition of the drive signal selection circuit

[0150] Next, the configuration and operation of the drive signal selection circuit 200 of the printhead 22 will be explained. As described above, the drive signal selection circuit 200 of the printhead 22 generates a drive signal VOUT by selecting or not selecting the signal waveform included in the drive signal COM based on the clock signal SCK, the print data signal SI, the latch signal LAT, and the change signal CH, and outputs it to the corresponding piezoelectric element 60. Therefore, when explaining the configuration and operation of the drive signal selection circuit 200, an example of the waveform of the drive signal COM input to the drive signal selection circuit 200 will be explained first.

[0151] Figure 10 An example of the signal waveform for the drive signal COM is shown. Figure 10 As shown, the drive signal COM includes: a trapezoidal waveform Adp, configured during the period t1 from the rise of the latch signal LAT to the rise of the change signal CH; a trapezoidal waveform Bdp, configured during the period t2 from the rise of the change signal CH to the next rise of the change signal CH; and a trapezoidal waveform Cdp, configured during the period t3 from the rise of the change signal CH to the rise of the latch signal LAT. The trapezoidal waveform Adp is a signal waveform that drives the piezoelectric element 60 to eject a predetermined amount of ink, the trapezoidal waveform Bdp is a signal waveform that drives the piezoelectric element 60 to eject a smaller amount of ink than the predetermined amount, and the trapezoidal waveform Cdp is a signal waveform that drives the piezoelectric element 60 to achieve a level where no ink is ejected. Here, when the trapezoidal waveform Cdp is supplied to the piezoelectric element 60, the piezoelectric element 60 is a signal waveform used to reduce the possibility of increased ink viscosity near the nozzle orifice by causing vibration of the ink near the corresponding nozzle orifice.

[0152] Furthermore, the trapezoidal waveforms Adp, Bdp, and Cdp are signal waveforms whose start and end timing voltage values ​​are identical in terms of voltage Vc. That is, the trapezoidal waveforms Adp, Bdp, and Cdp each begin and end with voltage Vc.

[0153] In the following description, the amount of ink ejected in accordance with a predetermined quantity when a trapezoidal waveform Adp is supplied to the piezoelectric element 60 is sometimes referred to as a medium quantity, and the amount of ink ejected less than the predetermined quantity when a trapezoidal waveform Bdp is supplied to the piezoelectric element 60 is sometimes referred to as a small quantity. Furthermore, the action used to vibrate the ink near the nozzle opening corresponding to the piezoelectric element 60 to prevent an increase in ink viscosity when a trapezoidal waveform Cdp is supplied to the piezoelectric element 60 is sometimes referred to as micro-vibration. It should be noted that... Figure 10 The waveform of the drive signal COM shown is just one example and is not limited to it. The waveform of the drive signal COM can also be varied by different combinations of waveforms depending on the properties of the ink being sprayed and the material of the medium P on which the ink lands.

[0154] Furthermore, the drive signal selection circuit 200 selects or deselects the trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM during the period tp, which includes periods t1, t2, and t3. Thus, the drive signal selection circuit 200 controls the amount of ink ejected from the multiple nozzles 321 during the period tp. That is, the drive signal selection circuit 200 controls the size of the dots formed on the medium P during the period tp. During the period tp, which includes periods t1, t2, and t3, dots of a predetermined size are formed on the medium P. The period tp in which the dots of this predetermined size are formed corresponds to the dot formation period.

[0155] Next, the configuration and operation of the drive signal selection circuit 200, which generates the drive signal VOUT by selecting or not selecting the signal waveform included in the drive signal COM, will be explained. Figure 11 This is a diagram showing the configuration of the drive signal selection circuit 200. (See diagram for example.) Figure 11 As shown, the drive signal selection circuit 200 includes a selection control circuit 210 and a plurality of selection circuits 230, the same number as the plurality of piezoelectric elements 60. It should be noted that in the following description, the printhead 22 is described as having p piezoelectric elements 60. That is, the drive signal selection circuit 200 has p selection circuits 230.

[0156] The selection control circuit 210 receives a clock signal SCK, a printed data signal SI, a latch signal LAT, and a change signal CH. Furthermore, within the selection control circuit 210, groups of shift registers (S / R) 212, latch circuits 214, and decoders 216 are respectively provided for each of the p piezoelectric elements 60. That is, the drive signal selection circuit 200 includes p shift registers 212, p latch circuits 214, and p decoders 216.

[0157] The print data signal SI is input to the selection control circuit 210 synchronously with the clock signal SCK. Furthermore, the print data signal SI and each of the p piezoelectric elements 60 serially include 2-bit print data [SIH, SIL] for selecting any one of "large dot LD", "medium dot MD", "small dot SD", and "no recording ND". The print data [SIH, SIL] included in the print data signal SI is stored in p shift registers 212 corresponding to the p p piezoelectric elements 60. Specifically, the p shift registers 212 corresponding to the p piezoelectric elements 60 are cascaded together, and the serially input print data signal SI is sequentially transmitted to the subsequent shift register 212 according to the clock signal SCK. Furthermore, the clock signal SCK stops when the print data [SIH, SIL] is stored in the corresponding shift register 212. Thus, the print data [SIH, SIL] included in the print data signal SI is stored in the corresponding shift register 212. It should be noted that... Figure 11 In order to distinguish the p shift registers 212, they are sequentially labeled as level 1, level 2, ..., level p, starting from the upstream side of the input printed data signal SI.

[0158] Each of the p latch circuits 214 latches the printed data [SIH, SIL] held in its corresponding shift register 212 simultaneously when the latch signal LAT rises. Furthermore, the printed data [SIH, SIL] latched by the latch circuits 214 is input to the corresponding decoder 216. Figure 12 This diagram illustrates an example of the decoded content in decoder 216. Decoder 216 outputs selection signals S at logic levels specified by the input printed data [SIH,SIL] during periods t1, t2, and t3, respectively. For example, when printed data [SIH,SIL] = [1,0] is input to decoder 216, decoder 216 outputs the logic level of selection signal S as H, L, and L levels during periods t1, t2, and t3.

[0159] The selection signal S output by the decoder 216 is input to the selection circuit 230. The selection circuit 230 is configured corresponding to each of the p piezoelectric elements 60. That is, the drive signal selection circuit 200 has the same number of selection circuits 230 as the p p piezoelectric elements 60. Figure 13 This is a diagram showing the configuration of the selection circuit 230. (As shown) Figure 13 As shown, the selection circuit 230 includes an inverter 232 and a transmission gate 234, which are NOT circuits.

[0160] The selection signal S is input to the positive control terminal (not marked with a circle) of transmission gate 234, and after its logic level is inverted by inverter 232, it is also input to the negative control terminal (marked with a circle) of transmission gate 234. Additionally, a drive signal COM is supplied to the input terminal of transmission gate 234. Furthermore, when the selection signal S is input at a high level, transmission gate 234 sets the input terminal to conduct between the input and output terminals; when the selection signal S is input at a low level, it sets the input terminal to de-conduct between the input and output terminals. That is, when the logic level of the selection signal S is high, transmission gate 234 outputs the signal waveform included in the drive signal COM from its output terminal; when the logic level of the selection signal S is low, it does not output the signal waveform included in the drive signal COM from its output terminal. Furthermore, the drive signal selection circuit 200 outputs the signal output to the output terminal of transmission gate 234 of the selection circuit 230 as the drive signal VOUT.

[0161] Here, using Figure 14 The operation of the drive signal selection circuit 200 is explained. Figure 14 This diagram illustrates the operation of the drive signal selection circuit 200. The print data signal SI is input to the selection control circuit 210 as a serial signal synchronized with the clock signal SCK. Furthermore, the print data signal SI is sequentially transmitted in p shift registers 212 corresponding to p p piezoelectric elements 60, synchronized with the clock signal SCK. Then, when the input of the clock signal SCK stops, the print data [SIH, SIL] corresponding to each of the p piezoelectric elements 60 is held in the shift registers 212. It should be noted that the print data signal SI is input in the order corresponding to the p-th, ..., 2-th, and 1-th stages of the shift registers 212.

[0162] Additionally, when the latch signal LAT rises, the latch circuit 214 simultaneously latches the printed data [SIH, SIL] held in the shift register 212. It should be noted that... Figure 14 The LT1, LT2, ..., LTp shown represent the printed data [SIH, SIL] latched by the latch circuit 214 corresponding to the shift registers 212 of level 1, level 2, ..., level p.

[0163] Decoder 216, based on the size of the dots specified by the latched print data [SIH, SIL], respectively, during periods t1, t2, and t3, respectively... Figure 12 The output select signal S is shown to be at a logic level. Additionally, the selection circuit 230 generates a drive signal VOUT by selecting or not selecting the signal waveform included in the drive signal COM, based on the logic level of the select signal S output by the decoder 216.

[0164] Specifically, when printed data [SIH,SIL] = [1,1] is input to decoder 216, decoder 216 sets the logic level of selection signal S to H, H, L levels during periods t1, t2, and t3. Therefore, selection circuit 230 selects trapezoidal waveform Adp during period t1, trapezoidal waveform Bdp during period t2, and does not select trapezoidal waveform Cdp during period t3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to "large point LD".

[0165] When the drive signal VOUT corresponding to the "large dot LD" is supplied to the piezoelectric element 60, a moderate amount of ink is ejected during period t1, a small amount of ink is ejected during period t2, and no ink is ejected during period t3. In addition, the moderate and small amounts of ink ejected fall onto and bind to the medium P, thereby forming a "large dot LD" on the medium P.

[0166] Furthermore, when printed data [SIH,SIL] = [1,0] is input to decoder 216, decoder 216 sets the logic level of selection signal S to H, L, L levels during periods t1, t2, and t3. Consequently, selection circuit 230 selects trapezoidal waveform Adp during period t1, does not select trapezoidal waveform Bdp during period t2, and does not select trapezoidal waveform Cdp during period t3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to the "midpoint MD".

[0167] When the drive signal VOUT corresponding to the "midpoint MD" is supplied to the piezoelectric element 60, a moderate amount of ink is ejected during period t1, no ink is ejected during period t2, and no ink is ejected during period t3. In addition, the moderate amount of ink ejected falls onto the medium P, thereby forming the "midpoint MD" on the medium P.

[0168] Furthermore, when printed data [SIH,SIL] = [0,1] is input to decoder 216, decoder 216 sets the logic level of selection signal S to L, H, and L levels during periods t1, t2, and t3. Consequently, selection circuit 230 does not select trapezoidal waveform Adp during period t1, selects trapezoidal waveform Bdp during period t2, and does not select trapezoidal waveform Cdp during period t3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to "small dot SD".

[0169] When the drive signal VOUT corresponding to the "small dot SD" is supplied to the piezoelectric element 60, no ink is ejected during period t1, a small amount of ink is ejected during period t2, and no ink is ejected during period t3. In addition, the small amount of ink ejected falls onto the medium P, thereby forming the "small dot SD" on the medium P.

[0170] Furthermore, when printed data [SIH,SIL] = [0,0] is input to decoder 216, decoder 216 sets the logic level of selection signal S to L, L, H levels during periods t1, t2, and t3. Consequently, selection circuit 230 does not select trapezoidal waveform Adp during period t1, does not select trapezoidal waveform Bdp during period t2, and selects trapezoidal waveform Cdp during period t3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to "Do not record ND".

[0171] When the drive signal VOUT corresponding to "No ND Recording" is supplied to the piezoelectric element 60, no ink is ejected during period t1, no ink is ejected during period t2, and no ink is ejected during period t3. Therefore, it becomes "No ND Recording" where no dot is formed on the medium P. At this time, the drive signal VOUT including the trapezoidal waveform Cdp is input to the corresponding piezoelectric element 60. Therefore, micro-vibration is performed. As a result, the possibility of increased ink viscosity near the opening of the corresponding nozzle 321 is reduced.

[0172] As described above, the drive signal selection circuit 200 generates a drive signal VOUT and outputs it to the corresponding piezoelectric element 60 by selecting or not selecting the signal waveform of the drive signal COM output by the drive circuit 50. Therefore, the drive signal VOUT includes any one of the trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM output by the drive circuit 50. In this way, the printhead 22 that ejects ink based on the drive signal VOUT can also be regarded as ejecting ink based on the drive signal COM.

[0173] Functional structure and operation of temperature information output circuit

[0174] Next, the functional configuration of the temperature information output circuit 26 of the head unit 20 will be explained. Figure 15 This diagram illustrates the functional configuration of the temperature information output circuit 26. Based on the temperature acquisition request signal TD input from the control circuit 100, the temperature information output circuit 26 generates temperature information signals TI corresponding to the head temperature signals TC1 to TCn, which respectively include head temperature information tc1 to tcn input from the printheads 22-1 to 22-n, and the unit temperature signal TH, which includes unit temperature information th input from the temperature detection circuit 28, and outputs these signals to the control circuit 100.

[0175] like Figure 15 As shown, the temperature information output circuit 26 includes a control circuit 500, amplifier circuits 510-1 to 510-n and 520, a multiplexer 530, an AD conversion circuit 540 and 550, and a storage circuit 560.

[0176] The corresponding head temperature signals TC1 to TCn are input to the amplifier circuits 510-1 to 510-n respectively. In addition, the amplifier circuits 510-1 to 510-n amplify the input head temperature signals TC1 to TCn to generate amplified head temperature signals ATC1 to ATCn and output them respectively.

[0177] Specifically, the printhead temperature signal TC1 output by the printhead 22-1 is input to the amplifier circuit 510-1. The amplifier circuit 510-1 amplifies the input printhead temperature signal TC1 and outputs it as the amplified printhead temperature signal ATC1. Additionally, the printhead temperature signal TCi output by the printhead 22-i is input to the amplifier circuit 510-i (where i is any one from 1 to n). The amplifier circuit 510-i amplifies the input printhead temperature signal TCi and outputs it as the amplified printhead temperature signal ATCi.

[0178] The head-amplified temperature signals ATC1 to ATCn output from amplifier circuits 510-1 to 510-n are input to multiplexer 530. Additionally, a selection signal Sel output from control circuit 500 is input to multiplexer 530. Multiplexer 530 selects any one of the head-amplified temperature signals ATC1 to ATCn input from amplifier circuits 510-1 to 510-n according to the input selection signal Sel, and outputs it as the selected temperature signal STC.

[0179] The AD conversion circuit 540 receives the selected temperature signal STC output by the multiplexer 530 and the enable signal EN output by the control circuit 500. The AD conversion circuit 540 converts the selected temperature signal STC input from the control circuit 500 into a digital signal while the enable signal EN is active and outputs it to the control circuit 500. That is, the AD conversion circuit 540 generates a digital signal and outputs it to the control circuit 500. This digital signal corresponds to the head temperature information tc included in the head temperature signal TC selected by the multiplexer 530 during the active period of the enable signal EN, among the head temperature signals TC1 to TCn input to the temperature information output circuit 26, and includes information corresponding to the temperature of the printhead 22 corresponding to the head temperature signal TC selected by the multiplexer 530 during the active period of the enable signal EN. In the following description, the digital signal output by the AD conversion circuit 540 is referred to as the digital temperature information dtc.

[0180] The unit temperature signal TH is input to the amplifier circuit 520. Furthermore, the amplifier circuit 520 amplifies the input unit temperature signal TH and outputs it as the amplified unit temperature signal ATH.

[0181] The AD conversion circuit 550 receives the amplified temperature signal ATH from the amplifier circuit 520 and the enable signal EN from the control circuit 500. The AD conversion circuit 550 converts the amplified temperature signal ATH, input during the period when the enable signal EN is active from the control circuit 500, into a digital signal and outputs it to the control circuit 500. Specifically, the AD conversion circuit 540 generates a digital signal and outputs it to the control circuit 500. This digital signal corresponds to the unit temperature information th included in the unit temperature signal TH input during the period when the enable signal EN is active, including information corresponding to the temperature of the head unit 20 during the period when the enable signal EN is active. In the following description, the digital signal output by the AD conversion circuit 550 is sometimes referred to as the digital temperature information dth.

[0182] The control circuit 500 includes a request parsing unit 502, a correction function calculation unit 504, a correction output unit 506, and a memory control unit 508. Furthermore, the control circuit 500 outputs a selection signal Sel and an enable signal EN corresponding to the input temperature acquisition request signal TD, and generates and outputs a temperature information signal TI based on the digital temperature information dtc and dth input according to the output of the selection signal Sel and the enable signal EN.

[0183] Specifically, the request analysis unit 502 analyzes the temperature acquisition request signal TD input to the control circuit 500. Additionally, the request analysis unit 502 outputs a selection signal Sel and an enable signal EN corresponding to the analysis result.

[0184] The correction function calculation unit 504 calculates a correction function based on the input digital temperature information dtc and dth to correct the signal output as temperature information signal TI that corresponds to the temperature of printheads 22-1 to 22-n.

[0185] The correction output unit 506 uses the correction function calculated by the correction function calculation unit 504 to correct the signal corresponding to the temperature of the printheads 22-1 to 22-n, and outputs it as a temperature information signal TI.

[0186] The memory control unit 508 generates a memory control signal MA for accessing the memory circuit 560 and outputs it to the memory circuit 560, and acquires a memory read signal MR corresponding to the memory control signal MA. For example, the memory control unit 508 generates a memory control signal MA that stores the input digital temperature information dtc, dth, and the calculated correction function in the memory circuit 560, and outputs it to the memory circuit 560. Thus, the digital temperature information dtc, dth, and the correction function are stored in a predetermined storage area of ​​the memory circuit 560. Additionally, the memory control unit 508 generates a memory control signal MA for reading information stored in the memory circuit 560 and outputs it to the memory circuit 560. Thus, a memory read signal MR including information read from the memory circuit 560 is input.

[0187] The method for generating the correction function in the temperature information output circuit 26 configured as described above, and a specific example of correction using the correction function will be explained.

[0188] Figure 16 This diagram illustrates the operation of the temperature information output circuit 26. (For example...) Figure 16 As shown, when the liquid dispensing device 1 is activated, the control circuit 100 executes the activation process (step S10). Here, the activation process of the liquid dispensing device 1 refers to the process executed, for example, by supplying power voltage to the liquid dispensing device 1 or by the user pressing the switch of the liquid dispensing device 1, including reading information stored in a storage circuit (not shown).

[0189] In addition, after the start-up process of the liquid ejection device 1 begins, the temperature information output circuit 26 of the head unit 20 of the liquid ejection device 1 performs correction function calculation processing (step S20) to calculate the correction functions corresponding to the print heads 22-1 to 22-n respectively.

[0190] Specifically, as part of the correction function calculation process, the control circuit 100 outputs a control signal Ctrl-W to control the temperature of the heating unit 80, including the heater 84, to a first temperature. The temperature information output circuit 26 acquires and holds the head temperature information tc1-tcn included in the head temperature signals TC1-TCn and the unit temperature information th included in the unit temperature signal TH. Then, the control circuit 100 outputs a control signal Ctrl-W to control the temperature of the heating unit 80, including the heater 84, to a second temperature different from the first temperature. The temperature information output circuit 26 acquires and holds the head temperature information tc1-tcn included in the head temperature signals TC1-TCn and the unit temperature information th included in the unit temperature signal TH.

[0191] That is, at least two temperatures—when the temperature of the heater 84 in the heating unit 80 is a first temperature and when the temperature of the heater 84 in the heating unit 80 is a second temperature—the temperature information output circuit 26 acquires and holds the head temperature information tc1 to tcn included in the head temperature signals TC1 to TCn and the unit temperature information th included in the unit temperature signal TH. Furthermore, the temperature information output circuit 26 uses the held head temperature information tc1 to tcn and unit temperature information th under the first temperature condition, and the head temperature information tc1 to tcn and unit temperature information th under the second temperature condition, to calculate a correction function.

[0192] Such correction function calculation processing can be performed by inputting the temperature acquisition request signal TD output by the control circuit 100 to the temperature information output circuit 26. Alternatively, it can be performed after a predetermined time has elapsed since the control circuit 100 started the processing. Furthermore, the first temperature or the second temperature can be the temperature at which the heater 84 of the heating unit 80 is in the OFF state, or it can be the ambient temperature surrounding the liquid spraying device 1. It should be noted that details regarding the correction function calculation processing shown in step S20 will be described later.

[0193] After the correction function calculation is completed, the control circuit 100 determines whether an image information signal has been input to the liquid ejection device 1 (step S30). If the control circuit 100 determines that no image information signal has been input to the liquid ejection device 1 (step S30 is "No"), the control circuit 100 determines whether a stop request to stop the operation of the liquid ejection device 1 has been generated (step S70). Here, stopping the operation of the liquid ejection device 1 includes not only the state of stopping the supply of power voltage to the liquid ejection device 1, but also a so-called sleep state in which standby is in a state of reduced power consumption. As a stop request to stop the operation of the liquid ejection device 1, for example, there are requests generated by the user pressing the corresponding switch to stop the operation of the liquid ejection device 1, requests generated by stopping the supply of power voltage to the liquid ejection device 1, etc.

[0194] Furthermore, if the control circuit 100 determines that no stop request has been generated in the liquid ejection device 1 (step S70 is "No"), the control circuit 100 again determines whether an image information signal has been input to the liquid ejection device 1 (step S30). That is, the liquid ejection device 1 remains in standby mode until the image information signal is input or a stop request is generated.

[0195] On the other hand, when the control circuit 100 determines that an image information signal has been input to the liquid ejection device 1 (step S30 is "Yes"), the control circuit 100 performs a printing process to form an image based on the input image information signal on the medium P (step S40). The printing process refers to the process in which, based on the base drive signal dA1 output by the control circuit 100, the drive circuit 50 outputs the drive signal COM to the head unit 20, and the control circuit 100 outputs the printing data signal SI, the latch signal LAT, and the change signal CH to the head unit 20, thereby generating a drive signal VOUT by the drive signal selection circuits 200 included in the print heads 22-1 to 22-n of the head unit 20, and ejecting a predetermined amount of ink from the print heads 22-1 to 22-n at a predetermined time.

[0196] Furthermore, during the printing process performed by the control circuit 100, the temperature information output circuit 26 performs temperature information output processing (step S50) based on the temperature acquisition request signal TD, outputting temperature information signals TI representing the temperatures of the printheads 22-1 to 22-n respectively. Specifically, the temperature information output circuit 26 acquires the printhead temperature information tc of the printhead 22 specified by the input temperature acquisition request signal TD. Additionally, it corrects the acquired printhead temperature information tc using a correction function calculated in the correction function calculation process, and outputs the corrected signal as the temperature information signal TI. It should be noted that details regarding the temperature information acquisition processing will be described later.

[0197] Then, the control circuit 100 performs a correction process for the liquid ejection device 1 based on the temperature information signal TI input from the temperature information output circuit 26 (step S60). Here, the correction process for the liquid ejection device 1 includes, for example, the correction of the control signals Ctrl-H, Ctrl-C, and Ctrl-T output by the control circuit 100. As a result, each component of the liquid ejection device 1 can operate according to the temperature of the printheads 22-1 to 22-n, that is, the temperature of the ink stored in the printheads 22-1 to 22-n respectively. Consequently, the ejection accuracy of the ink from the printheads 22-1 to 22-n and the landing accuracy of the ejected ink on the medium P are improved, and the image quality formed on the medium P is improved.

[0198] After the calibration process of the liquid ejection device 1 is completed, the control circuit 100 determines whether a stop request to stop the operation of the liquid ejection device 1 has been generated (step S70). If no stop request is generated in the liquid ejection device 1 (step S70 is "No"), the control circuit 100 determines whether an image information signal has been input to the liquid ejection device 1 (step S30). On the other hand, if a stop request is generated in the liquid ejection device 1 (step S70 is "Yes"), the control circuit 100 executes the stop process of the liquid ejection device 1 (step S80), and then the liquid ejection device 1 stops operating.

[0199] As described above, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 calculates a correction function based on the unit temperature information th and the head temperature information tc input when the heating unit 80 is heating at a predetermined temperature during the correction function calculation process. Furthermore, the temperature information output circuit 26 outputs a temperature information signal TI corrected using the calculated correction function. In other words, the temperature information output circuit 26 corrects the head temperature information tc, which is output as the temperature information signal TI, based on the unit temperature information th and the head temperature information tc input when the heating unit 80 is heating at at least one of a first temperature and a second temperature.

[0200] Next, a specific example of the above correction function calculation and processing will be explained. Figure 17 This is a diagram used to illustrate an example of the calculation and processing of the correction function.

[0201] like Figure 17 As shown, by inputting a temperature acquisition request signal TD (step S210) from the control circuit 100 to the temperature information output circuit 26, indicating the execution of the correction function calculation process, the liquid ejection device 1 performs the correction function calculation process. As the correction function calculation process, firstly, a first temperature information acquisition process is performed, that is, corresponding to the head temperature information tc1 to tcn included in the head temperature signals TC1 to TCn output by the printheads 22-1 to 22-n respectively when the temperature of the heating unit 80 is the first temperature, the unit temperature information th included in the unit temperature signal TH output by the temperature detection circuit 28 is acquired (step S220).

[0202] Specifically, in the first temperature information acquisition process, the control circuit 100 outputs a control signal Ctrl-W to control the temperature of the heating unit 80 to a first temperature. Thus, the temperature of the heating unit 80 is controlled to the first temperature (step S221). Additionally, the temperature information output circuit 26 initializes the variable j to j = 1 (step S222). That is, the temperature information output circuit 26 performs the first temperature information acquisition process corresponding to the print head 22-1.

[0203] Then, the control circuit 500 included in the temperature information output circuit 26 outputs the selection signal Sel to the multiplexer 530. Since variable j is "1", the selection signal Sel selects the amplified head temperature signal ATC1 after the head temperature signal TC1 output by the printhead 22-1 is amplified by the amplification circuit 510-1. Thus, the multiplexer 530 selects the amplified head temperature signal ATC1 (step S223) as the amplified head temperature signal ATCj and outputs it as the selected temperature signal STC.

[0204] Then, the control circuit 500 included in the temperature information output circuit 26 outputs an enable signal EN to enable the analog-to-digital conversion in the AD conversion circuits 540 and 550. As a result, the AD conversion circuit 540 outputs digital temperature information dtc, which is the selected temperature signal STC converted from the head-amplified temperature signal ATC1, and the AD conversion circuit 550 outputs digital temperature information dth, which is the unit-amplified temperature signal ATH amplified by the amplifier circuit 520 and converted into a digital signal after being converted into a digital signal. Additionally, the control circuit 500 acquires the digital temperature information dtc output by the AD conversion circuit 540 and the digital temperature information dth output by the AD conversion circuit 550 (step S224).

[0205] Then, the memory control unit 508 of the control circuit 500 outputs a memory control signal MA to store the acquired digital temperature information dtc as first head temperature information tgc1-1 representing the temperature corresponding to printhead 22-j, i.e., printhead 22-1, in the memory circuit 560 (step S225). Additionally, the memory control unit 508 of the control circuit 500 outputs a memory control signal MA to store the acquired digital temperature information dth as first unit temperature information tgh1-1 representing the temperature of the head unit 20 when the first head temperature information tgc1-1 is acquired in the memory circuit 560 (step S226). That is, the temperature of printhead 22-1 during the heating period of the heating unit 80 at the first temperature and the temperature of the head unit 20 when the temperature of printhead 22-1 is acquired are correspondingly stored in the memory circuit 560.

[0206] Then, the temperature information output circuit 26 adds "1" to variable j (step S227) and determines whether the added variable j is less than or equal to "n" of the total number of printheads 22 included in the head unit 20 (step S228). If variable j is less than or equal to "n" of the total number of printheads 22 included in the head unit 20 (step S228 is "yes"), the temperature information output circuit 26 repeats steps S223 to S228. Thus, the temperature information output circuit 26 performs the first temperature information acquisition process described above on printheads 22-1 to 22-n respectively. Then, if variable j exceeds "n" of the total number of printheads 22 included in the head unit 20 (step S228 is "no"), the temperature information output circuit 26 terminates the first temperature information acquisition process.

[0207] That is, in the first temperature information acquisition process, the heating unit 80 stores the temperature of the print head 22-1 to 22-n during the first temperature heating period and the temperature of the head unit 20 when acquiring the respective temperatures of the print head 22-1 to 22-n in the storage circuit 560 in the corresponding state.

[0208] In addition, after the first temperature information acquisition process is completed, the second temperature information acquisition process is performed, that is, when the temperature of the heating unit 80 is the second temperature, the unit temperature information th included in the head temperature signals TC1 to TCn output by the printheads 22-1 to 22-n respectively is acquired (step S230).

[0209] Specifically, in the second temperature information acquisition process, the control circuit 100 outputs a control signal Ctrl-W to control the temperature of the heating unit 80 to a second temperature different from the first temperature. Thus, the temperature of the heating unit 80 is controlled to the second temperature (step S231). Additionally, the temperature information output circuit 26 initializes the variable j to j = 1 (step S232). That is, the temperature information output circuit 26 performs the second temperature information acquisition process corresponding to the print head 22-1.

[0210] Then, the control circuit 500 included in the temperature information output circuit 26 outputs the selection signal Sel to the multiplexer 530. Since the variable j is "1", the selection signal Sel selects the amplified head temperature signal ATC1 after the head temperature signal TC1 output by the printhead 22-1 is amplified by the amplification circuit 510-1. Thus, the multiplexer 530 selects the amplified head temperature signal ATC1 as the amplified head temperature signal ATCj (step S233) and outputs it as the selected temperature signal STC.

[0211] Then, the control circuit 500 included in the temperature information output circuit 26 outputs an enable signal EN to enable the analog / digital conversion in the AD conversion circuits 540 and 550. As a result, the AD conversion circuit 540 outputs digital temperature information dtc, which is the selected temperature signal STC converted from the head-amplified temperature signal ATC1, and the AD conversion circuit 550 outputs digital temperature information dth, which is the unit-amplified temperature signal ATH amplified by the amplifier circuit 520 and converted into a digital signal after being converted into a digital signal. Then, the control circuit 500 acquires the digital temperature information dtc output by the AD conversion circuit 540 and the digital temperature information dth output by the AD conversion circuit 550 (step S234).

[0212] Then, the memory control unit 508 of the control circuit 500 outputs a memory control signal MA for storing the acquired digital temperature information dtc as second head temperature information tgc2-1 representing the temperature corresponding to print head 22-j, i.e., print head 22-1, in the memory circuit 560 (step S235). Additionally, the memory control unit 508 of the control circuit 500 outputs a memory control signal MA for storing the acquired digital temperature information dth as second unit temperature information tgh2-1 representing the temperature of the head unit 20 when the second head temperature information tgc2-1 is acquired in the memory circuit 560 (step S236). That is, the temperature of the print head 22-1 during the heating period of the heating unit 80 at the second temperature and the temperature of the head unit 20 when the temperature of the print head 22-1 is acquired are correspondingly stored in the memory circuit 560.

[0213] Then, the temperature information output circuit 26 adds "1" to variable j (step S237) and determines whether the summed variable j is less than or equal to "n" of the total number of printheads 22 included in the head unit 20 (step S238). If variable j is less than or equal to "n" of the total number of printheads 22 included in the head unit 20 (step S238 is "yes"), the temperature information output circuit 26 repeats steps S233 to S238. Thus, the temperature information output circuit 26 performs the second temperature information acquisition process described above on printheads 22-1 to 22-n respectively. Then, if variable j exceeds "n" of the total number of printheads 22 included in the head unit 20 (step S238 is "no"), the temperature information output circuit 26 terminates the second temperature information acquisition process.

[0214] That is, in the second temperature information acquisition process, the heating unit 80 stores the temperatures of the printheads 22-1 to 22-n during the second temperature heating period and the temperatures of the head unit 20 when acquiring the respective temperatures of the printheads 22-1 to 22-n in the storage circuit 560 in the corresponding states.

[0215] In addition, after the first temperature information acquisition processing and the second temperature information acquisition processing are completed, the temperature information output circuit 26 sequentially reads the first head temperature information tgc1-1~tgc1-n, the second head temperature information tgc2-1~tgc2-n, the first unit temperature information tgh1-1~tgh1-n, and the second unit temperature information tgh2-1~tgh2-n stored in the storage circuit, calculates the correction functions Cf1~Cfn corresponding to the print heads 22-1~22-n respectively, and executes the correction function acquisition processing stored in the storage circuit 560 (step S240).

[0216] Specifically, the correction function acquisition process is executed after the first temperature information acquisition process and the second temperature information acquisition process are performed. When the correction function acquisition process begins, the temperature information output circuit 26 initializes the variable j to j=1 (step S241). That is, the temperature information output circuit 26 performs the calculation of the correction function Cf1 corresponding to the print head 22-1.

[0217] First, the memory control unit 508 included in the temperature information output circuit 26 outputs a memory control signal MA from the memory circuit 560 for reading the first head temperature information tgc1-1 corresponding to the first head temperature information tgc1-j (i.e., print head 22-1), the second head temperature information tgc2-1 corresponding to the second head temperature information tgc2-j, the first unit temperature information tgh1-j corresponding to the first unit temperature information tgh1-j, and the second unit temperature information tgh2-1 corresponding to the second unit temperature information tgh2-j. Then, the first head temperature information tgc1-1, the second head temperature information tgc2-1, the first unit temperature information tgh1-1, and the second unit temperature information tgh2-1 are read from the memory circuit 560 and input as a memory read signal MR to the memory control unit 508. That is, the control circuit 500 reads the first head temperature information tgc1-1, the second head temperature information tgc2-1, the first unit temperature information tgh1-1, and the second unit temperature information tgh2-1 from the storage circuit 560 (step S242).

[0218] The first head temperature information tgc1-1, the second head temperature information tgc2-1, the first unit temperature information tgh1-1, and the second unit temperature information tgh2-1 input to the memory control unit 508 are input to the correction function calculation unit 504. The correction function calculation unit 504 calculates the correction function Cf1, which is the correction function Cfj, based on the input first head temperature information tgc1-1, second head temperature information tgc2-1, first unit temperature information tgh1-1, and second unit temperature information tgh2-1 (step S243).

[0219] Specifically, the correction function calculation unit 504 calculates a linear function as the correction function Cf1. This linear function calculates the temperature of the head unit 20 as the first unit temperature information tgh1-1 when the temperature of the print head 22-1 is the first head temperature information tgc1-1, and the temperature of the head unit 20 as the second unit temperature information tgh2-1 when the temperature of the print head 22-1 is the second head temperature information tgc2-1. That is, the correction function Cf1 in this embodiment is a function that uses the digital temperature information dtc based on the head temperature information tc1 as a variable.

[0220] It should be noted that the correction function Cf1 calculated by the correction function calculation unit 504 is not limited to the linear function mentioned above. An approximation can also be calculated as the correction function Cf1. This approximation is such that, when the temperature of the printhead 22-1 is the first head temperature information tgc1-1, the temperature of the head unit 20 is the first unit temperature information tgh1-1; and when the temperature of the printhead 22-1 is the second head temperature information tgc2-1, the temperature of the head unit 20 is the second unit temperature information tgh2-1. Here, the above approximation can also be an exponential approximation, a power approximation, a polynomial approximation, etc., depending on the temperature characteristics of the resistor wiring 401.

[0221] After the calculation of the correction function Cf1 in the correction function calculation unit 504 is completed, the memory control unit 508 generates a memory control signal MA for storing the calculated correction function Cf1 in the memory circuit 560 and outputs it to the memory circuit 560. Thus, the correction function Cf1 is stored in the memory circuit 560. That is, the memory control unit 508 stores the correction function Cf1 in the memory circuit 560 (step S244).

[0222] Then, the temperature information output circuit 26 adds "1" to variable j (step S245) and determines whether the summed variable j is less than or equal to "n" of the total number of printheads 22 included in the head unit 20 (step S246). If variable j is less than or equal to "n" of the total number of printheads 22 included in the head unit 20 (step S246 is "yes"), the temperature information output circuit 26 repeats steps S242 to S246. Thus, the temperature information output circuit 26 calculates correction functions Cf1 to Cfn corresponding to printheads 22-1 to 22-n respectively and stores them in the storage circuit 560. Then, if variable j exceeds "n" of the total number of printheads 22 included in the head unit 20 (step S246 is "no"), the temperature information output circuit 26 ends the correction function acquisition process and the correction function calculation process.

[0223] As described above, when the liquid ejection device 1 is started, the temperature information output circuit 26 holds the unit temperature information th included in the unit temperature signal TH input when the heating unit 80 is heating at the first temperature as the first unit temperature information tgh1-1, holds the head temperature information tc1 included in the head temperature signal TC1 input when the heating unit 80 is heating at the first temperature as the first head temperature information tgc1-1, holds the unit temperature information th included in the unit temperature signal TH input when the heating unit 80 is heating at the second temperature as the second unit temperature information tgh2-1, and holds the head temperature information tc1 included in the head temperature signal TC1 input when the heating unit 80 is heating at the second temperature as the second head temperature information tgc2-1.

[0224] In addition, the temperature information output circuit 26 calculates the correction function Cf1 based on the maintained first unit temperature information tgh1-1, second unit temperature information tgh2-1, first head temperature information tgc1-1, and second head temperature information tgc2-1.

[0225] Next, a specific example of the temperature information output processing described above will be explained. Figure 18 This is a diagram illustrating an example of temperature information output processing.

[0226] like Figure 18 As shown, during the printing process, the temperature information output circuit 26 starts the temperature information output process by inputting a temperature acquisition request signal TD (step S510) from the control circuit 100 to the temperature information output circuit 26 to request the temperature of any one of the multiple printheads 22.

[0227] When a temperature acquisition request signal TD is input to the temperature information output circuit 26 requesting the temperature of any one of the multiple printheads 22, the request parsing unit 502 included in the control circuit 500 of the temperature information output circuit 26 parses the temperature acquisition request signal TD to determine the printhead 22-k (k is any one from 1 to n) among the multiple printheads 22 for acquiring the temperature (step S520). Then, the temperature information output circuit 26 outputs a selection signal Sel to the multiplexer 530, which selects the amplified head temperature signal ATCk obtained by amplifying the head temperature signal TCk corresponding to the printhead 22-k through the amplification circuit 510-k. Thus, the multiplexer 530 selects the amplified head temperature signal ATCk as the amplified head temperature signal ATCk (step S530) and outputs it as the selected temperature signal STC.

[0228] Then, the control circuit 500 included in the temperature information output circuit 26 outputs an enable signal EN to enable the analog-to-digital conversion in the AD conversion circuit 540. As a result, the AD conversion circuit 540 outputs digital temperature information dtc, which is the selected temperature signal STC converted from the printhead amplification temperature signal ATCk into a digital signal. Additionally, the control circuit 500 acquires the digital temperature information dtc output by the AD conversion circuit 540 (step S540). That is, the control circuit 500 acquires the digital temperature information dtc corresponding to the printhead temperature information tck representing the temperature of the printhead 22-k.

[0229] Additionally, the memory control unit 508 included in the control circuit 500 outputs a memory control signal MA for reading the correction function Cfk from the correction functions Cf1 to Cfn stored in the memory circuit 560. As a result, the correction function Cfk is read from the memory circuit 560 and input to the memory control unit 508 as a memory read signal MR. That is, the control circuit 500 reads the correction function Cfk from the memory circuit 560 (step S550).

[0230] Furthermore, the correction output unit 506 included in the control circuit 500 performs correction by substituting the digital temperature information dtc corresponding to the head temperature information tck representing the temperature of the print head 22-k into the correction function Cfk. That is, the correction output unit 506 corrects the digital temperature information dtc corresponding to the head temperature information tck representing the temperature of the print head 22-k using the correction function Cfk (step S560). Additionally, the correction output unit 506 included in the control circuit 500 generates and outputs a temperature information signal TI that includes the corrected digital temperature information dtc as information representing the temperature of the print head 22-k. That is, the correction output unit 506 outputs the corrected signal as the temperature information signal TI (step S570). Thus, the temperature information output circuit 26 terminates the temperature information output processing.

[0231] That is, the temperature information output circuit 26 corrects the head temperature information tc1 included in the head temperature signal TC1 input when the printing process of ink ejection from the printhead 22-1 is executed, i.e., when the liquid is ejected, based on the first unit temperature information tgh1-1, the second unit temperature information tgh2-1, the first head temperature information tgc1-1, and the second head temperature information tgc2-1, and outputs it as the temperature information signal TI. Specifically, the temperature information output circuit 26 uses a correction function Cf1 calculated based on the first unit temperature information tgh1-1, the second unit temperature information tgh2-1, the first head temperature information tgc1-1, and the second head temperature information tgc2-1 to correct the head temperature information tc1 included in the head temperature signal TC1 input when the printing process of ink ejection from the printhead 22-1 is executed, i.e., when the liquid is ejected, and outputs it as the temperature information signal TI.

[0232] Here, the drive signal COM is an example of a drive signal. Since the drive signal VOUT is generated by selecting or not selecting the signal waveform included in the drive signal COM, the drive signal VOUT is also an example of a drive signal. The heating unit 80 is an example of a heating mechanism. The temperature detection circuit 28 is an example of a unit temperature detection circuit. Any one of the head temperature information tc1~tcn, i.e., head temperature information tc, is an example of head temperature information. Any one of the head temperature signals TC1~TCn, i.e., head temperature signal TC, is an example of a head temperature signal. The electrode 360 ​​is an example of a first electrode. The electrode 380 is an example of a second electrode. The direction along the Z-axis is an example of a stacking direction. The +Z side along the Z-axis is an example of one side of the stacking direction. The -Z side along the Z-axis is an example of the other side of the stacking direction. The temperature detection circuit 24 is an example of a head temperature detection unit. One of the first temperature and the second temperature is a predetermined temperature. For example, any one of the temperature information tgh1-1~tgh1-n of the first unit and any one of the temperature information tgh2-1~tgh2-n of the second unit is an example of the temperature information of the reference unit; any one of the temperature information tgh1-1~tgh1-n of the first unit is an example of the temperature information of the first reference unit; any one of the temperature information tgh2-1~tgh2-n of the second unit is an example of the temperature information of the second reference unit; any one of the temperature information tgc1-1~tgc1-n of the first head and any one of the temperature information tgc2-1~tgc2-n of the second head is an example of the temperature information of the reference head; any one of the temperature information tgc1-1~tgc1-n of the first head is an example of the temperature information of the first reference unit; any one of the temperature information tgc2-1~tgc2-n of the second head is an example of the temperature information of the second reference unit; any one of the correction functions Cf1~Cfn is an example of the correction function.

[0233] 3. Effects

[0234] In the liquid ejection device 1 configured as described above, the head unit 20 has a print head 22, which includes: a piezoelectric element 60, comprising electrodes 360, 380, and a piezoelectric body 370, wherein the piezoelectric body 370 is located between electrodes 360 and 380 in the Z-axis direction where electrodes 360, 380, and piezoelectric body 370 are stacked, and is driven by a drive signal COM; and a vibrating plate 350, located on the +Z side relative to the piezoelectric element 60 in the Z-axis direction, which is driven by the piezoelectric element 60. The pressure chamber substrate 310, located on the +Z side relative to the vibrating plate 350 along the Z-axis, is provided with a pressure chamber 312 whose volume changes according to the deformation of the vibrating plate 350; a nozzle 321 ejects liquid according to the change in volume of the pressure chamber 312; and a temperature detection circuit 24, including a resistor wiring 401 located on the -Z side relative to the vibrating plate 350 along the Z-axis, which acquires the head temperature information tc corresponding to the temperature of the corresponding pressure chamber 312 among a plurality of head temperature information tc. That is, the resistor wiring 401, which constitutes at least a part of the temperature detection circuit 24 for detecting the temperature of the printhead 22, is disposed in the printhead 22 near the pressure chamber 312 where ink ejected from the nozzle 321 is stored. As a result, the accuracy of acquiring the temperature of the pressure chamber 312 in the temperature detection circuit 24, that is, the accuracy of acquiring the temperature of the ink stored in the pressure chamber 312, is improved.

[0235] On the other hand, since the temperature detection circuit 24 obtains the temperature-based change in resistance value of the resistive wiring 401 formed on the vibrating plate 350 as the temperature of the ink stored in the pressure chamber 312, from the viewpoint of significantly obtaining the temperature-based change in resistance value, it is preferable that the wiring length of the resistive wiring 401 is long. Since the resistive wiring 401 is formed inside the printhead 22, from the viewpoint of miniaturizing the printhead 22, it is preferable that the wiring pattern of the resistive wiring 401 has a small wiring width. Therefore, the resistive wiring 401 is configured as a long and thin wiring pattern. Consequently, the resistance value may exhibit a large deviation.

[0236] In contrast, in the liquid ejection device 1 of this embodiment, the head unit 20 has a temperature detection circuit 28. The temperature detection circuit 28 detects the temperature of the head unit 20 as unit temperature information th and outputs a unit temperature signal TH including the detected unit temperature information th. The temperature information output circuit 26 corrects the head temperature information tc output as a temperature information signal TI based on the unit temperature information th included in the unit temperature signal TH input when the heating unit 80 is heated at at least one of a first temperature and a second temperature, and the head temperature information tc obtained by the temperature detection circuit 24. That is, the print head unit 20 of this embodiment has a temperature detection circuit 28, which is separate from the temperature detection circuit 24 disposed inside the print head 22. The temperature detection circuit 28 detects the overall temperature of the print head unit 20. During the heating unit 80 heating at a known temperature, i.e., a first temperature or a second temperature, the temperature information output circuit 26 corrects the print head temperature information tc, which is output as a temperature information signal TI, based on the unit temperature information th, which represents the temperature of the print head unit 20 output by the temperature detection circuit 28, and the print head temperature information tc, which represents the temperature of the print head 22 output by the temperature detection circuit 24 disposed inside the print head 22. Thus, the temperature information output circuit 26 obtains the temperature change caused by the heating of the heating unit 80 through the temperature detection circuit 28 and the temperature detection circuit 24, and corrects the print head temperature information tc obtained by the temperature detection circuit 24 based on the unit temperature information th obtained by the temperature detection circuit 28. Therefore, even if the temperature detection characteristics of the temperature detection circuit 24 located inside the printhead 22 deviate, the temperature information output circuit 26 can appropriately correct it and output a temperature information signal TI corresponding to the temperature of the printhead 22. That is, the temperature information output circuit 26 can output a temperature information signal TI that reduces the influence of the deviation in the temperature detection characteristics of the temperature detection circuit 24, i.e., a temperature information signal TI that accurately reflects the temperature of the printhead 22.

[0237] Furthermore, in the liquid ejection device 1 of this embodiment, as described above, the temperature information output circuit 26 disposed outside the printhead 22 corrects for deviations in the characteristics of the temperature detection circuit 24 disposed inside the printhead 22 based on the temperature detection result of the temperature detection circuit 28 disposed outside the printhead 22. Therefore, the temperature information output circuit 26 can correct for deviations in the printhead temperature signal TC caused by the propagation path of the printhead temperature signal TC output by the temperature detection circuit 24 and deviations in the circuit elements disposed along that path. As a result, the correction accuracy of the printhead temperature information TC in the temperature information output circuit 26 is further improved, and consequently, the temperature information output circuit 26 can output a temperature information signal TI that reflects the temperature of the printhead 22 with higher accuracy.

[0238] Furthermore, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 maintains the unit temperature information th and printhead temperature information tc input when the liquid ejection device 1 is started, i.e., during the period when no ink is ejected, when the heating unit 80 is heating at at least one of a first temperature and a second temperature, and corrects the printhead temperature information tc input during the printing process performed by the liquid ejection device 1, i.e., when the liquid is ejected, based on the maintained unit temperature information th and printhead temperature information tc. As a result, the influence of self-heating of the printhead 22 is reduced when the unit temperature information th and printhead temperature information tc, which serve as the correction reference, are acquired. As a result, the temperature difference generated between the temperature specified by the unit temperature information th, which serves as the correction reference, and the temperature specified by the printhead temperature information tc, which serves as the correction reference, can be reduced. Therefore, the correction accuracy of the temperature information output circuit 26 when correcting the printhead temperature information tc is further improved, and the temperature information output circuit 26 can output a temperature information signal TI that further reduces the influence of the deviation of the temperature detection characteristics of the temperature detection circuit 24, i.e., a temperature information signal TI that further reflects the temperature of the printhead 22 with high accuracy.

[0239] Furthermore, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 calculates a correction function to correct the head temperature information tc, which is output as a temperature information signal TI, based on the unit temperature information th and head temperature information tc input when the heating unit 80 is heated at a first temperature, and the unit temperature information th and head temperature information tc input when the heating unit 80 is heated at a second temperature different from the first temperature. Based on the calculated correction function, the temperature information output circuit 26 outputs the corrected head temperature information tc. That is, the temperature information output circuit 26 corrects the detected temperature of the temperature detection circuit 24 located inside the print head 22 based on multiple temperatures detected by the temperature detection circuit 28. Therefore, the temperature information output circuit 26 can output a temperature information signal TI that further reduces the deviation in the detection accuracy of the temperature detection circuit 24 located inside the print head 22, and can output a temperature information signal TI that further reduces the influence of the deviation in the temperature detection characteristics of the temperature detection circuit 24, i.e., a temperature information signal TI that further reflects the temperature of the print head 22 with higher accuracy.

[0240] At this time, the temperature information output circuit 26 uses a correction function calculated based on multiple temperatures detected by the temperature detection circuit 28 to correct the printhead temperature information tc, which is output as the temperature information signal TI. Thus, the temperature information output circuit 26 can correct the printhead temperature information tc, which is output as the temperature information signal TI, using an optimal correction value corresponding to the temperature of the printhead 22 based on the acquired printhead temperature information tc. As a result, a temperature information signal TI that further reduces the influence of deviations in the temperature detection characteristics of the temperature detection circuit 24 can be output, i.e., a temperature information signal TI that further reflects the temperature of the printhead 22 with higher accuracy.

[0241] Furthermore, in the liquid ejection device 1 of this embodiment, the heating unit 80 is configured to include a ceramic heater. This allows for faster temperature rise and fall of the heater 84, and reduces the time required to calculate the correction value of the temperature information signal TI.

[0242] Furthermore, in the liquid ejection device 1 of this embodiment, the heating unit 80 also functions as a so-called pressure plate heater for drying the medium P. Therefore, without the need for additional components, the temperature information signal TI output by the temperature information output circuit 26 can be corrected.

[0243] The embodiments and variations have been described above, but the present invention is not limited to these embodiments and can be implemented in various ways without departing from its spirit. For example, the above embodiments can also be appropriately combined.

[0244] This invention includes configurations that are substantially the same as those described in the embodiments (e.g., configurations with the same function, method, and result, or configurations with the same purpose and effect). Additionally, this invention includes configurations that replace non-essential parts of the configurations described in the embodiments. Furthermore, this invention includes configurations that achieve the same effect as those described in the embodiments or that can achieve the same purpose. Additionally, this invention includes configurations that incorporate known techniques into the configurations described in the embodiments.

[0245] The following content is derived from the above implementation method.

[0246] One method of liquid ejection device includes:

[0247] The head unit ejects liquid into the medium based on a drive signal; and

[0248] Fever-inducing institutions

[0249] The head unit has:

[0250] The printhead ejects liquid based on the drive signal;

[0251] A unit temperature detection circuit detects the temperature of the head unit as unit temperature information and outputs a unit temperature signal including the unit temperature information; and

[0252] The temperature information output circuit receives the unit temperature signal and a head temperature signal, which includes head temperature information corresponding to the temperature of the print head, and outputs a temperature information signal.

[0253] The printhead includes:

[0254] A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode and receives the driving signal to drive it.

[0255] The vibrating plate is located on one side of the piezoelectric element in the stacking direction and is deformed by the piezoelectric element.

[0256] A pressure chamber substrate, located on one side of the vibrating plate in the stacking direction, is provided with a pressure chamber whose volume varies according to the deformation of the vibrating plate;

[0257] A nozzle that ejects liquid according to changes in the volume of the pressure chamber; and

[0258] The head temperature detection unit, located on the opposite side of the vibrating plate in the stacking direction, detects the head temperature information corresponding to the temperature of the pressure chamber and outputs it as the head temperature signal.

[0259] The temperature information output circuit corrects the head temperature information, which is output as a temperature information signal, based on the unit temperature information and the head temperature information input when the heating mechanism heats up at a specified temperature.

[0260] According to this liquid ejection device, the head temperature detection unit, which detects head temperature information corresponding to the temperature of the pressure chamber, is located near the pressure chamber, thereby enabling the temperature detection unit to detect the temperature of the pressure chamber, i.e., the temperature of the liquid stored in the pressure chamber, with high accuracy.

[0261] Furthermore, according to this liquid ejection device, in addition to the head temperature detection unit that detects the temperature of the pressure chamber, there is also a unit temperature detection circuit that detects the temperature of the head unit. The temperature information output circuit corrects the temperature information signal representing the temperature of the printhead based on the unit temperature information output by the unit temperature detection circuit and the head temperature information output by the head temperature detection unit during the heating period when the heating mechanism is heating at a predetermined temperature. That is, by acquiring the temperature change caused by the heating of the heating mechanism through the unit temperature detection circuit located outside the printhead and the head temperature detection unit located inside the printhead, the temperature information output circuit corrects the head temperature information detected by the head temperature detection unit located inside the printhead based on the unit temperature information detected by the unit temperature detection circuit located outside the printhead. Thus, even if the temperature detection characteristics of the head temperature detection unit located inside the printhead deviate, the temperature information output circuit can correct for the deviation and output a temperature information signal corresponding to the temperature of the printhead.

[0262] In one embodiment of the aforementioned liquid ejection device

[0263] The temperature information output circuit may also retain the unit temperature information contained in the unit temperature signal input at startup, i.e., when the heating mechanism is heating at a specified temperature, as the reference unit temperature information.

[0264] The head temperature information included in the head temperature signal input at startup, i.e., when the heating mechanism heats up at the specified temperature, will be retained as the reference head temperature information.

[0265] Based on the reference unit temperature information and the reference head temperature information, the head temperature information contained in the head temperature signal input when the liquid is ejected from the print head is corrected and output as the temperature information signal.

[0266] According to this liquid ejection device, the temperature change caused by the heating mechanism during startup is acquired by a unit temperature detection circuit located outside the printhead and a head temperature detection unit located inside the printhead, thereby reducing the impact of self-heating of the printhead. As a result, the correction accuracy of the temperature information output circuit when correcting the head temperature information detected by the head temperature detection unit located inside the printhead, based on the unit temperature information detected by the unit temperature detection circuit located outside the printhead, is improved. Therefore, the correction accuracy of the temperature information output circuit for deviations in the temperature detection characteristics of the head temperature detection unit is improved, and the accuracy of the temperature information signal corresponding to the temperature of the printhead is further improved.

[0267] In one embodiment of the aforementioned liquid ejection device

[0268] The temperature information output circuit may also retain the unit temperature information contained in the unit temperature signal input when the heating mechanism is heating at a first temperature, which is the specified temperature, as the first reference unit temperature information.

[0269] The head temperature information contained in the head temperature signal input when the heating mechanism heats up at the first temperature is retained as the first reference head temperature information.

[0270] The unit temperature information contained in the unit temperature signal input when the heating mechanism heats at a second temperature, which is the specified temperature, is retained as the second reference unit temperature information.

[0271] The head temperature information contained in the head temperature signal input when the heating mechanism heats up at the second temperature is retained as the second reference head temperature information.

[0272] The correction function is calculated based on the maintained temperature information of the first reference unit, the second reference unit, the first reference head, and the second reference head.

[0273] The correction function is used to correct the head temperature information contained in the head temperature signal input when the liquid is ejected from the printhead, and the correction is output as the temperature information signal.

[0274] According to the liquid ejection device, the temperature information output circuit, based on the first reference unit temperature information and the first reference head temperature information obtained when the heating mechanism is at a first temperature, and the second reference unit temperature information and the second reference head temperature information obtained when the heating mechanism is at a second temperature, uses the unit temperature information detected by the unit temperature detection circuit located outside the print head as a reference to correct the head temperature information detected by the head temperature detection unit located inside the print head. As a result, the correction accuracy of the temperature information output circuit for the deviation of the temperature detection characteristics of the head temperature detection unit is further improved, and the accuracy of the temperature information signal corresponding to the temperature of the print head is further improved.

[0275] Furthermore, according to this liquid ejection device, a correction function is used to correct the head temperature information detected by the head temperature detection unit located inside the printhead, based on the unit temperature detection circuit located outside the printhead. As a result, the temperature information output circuit can perform correction using the optimal correction value corresponding to the printhead temperature, based on the acquired head temperature information. Consequently, the correction accuracy of the temperature information output circuit for deviations in the temperature detection characteristics of the head temperature detection unit is further improved, and the accuracy of the temperature information signal corresponding to the printhead temperature is further improved.

[0276] In one embodiment of the aforementioned liquid ejection device

[0277] The heating mechanism may also include a ceramic heater.

[0278] According to this liquid ejection device, by using a ceramic heater as the heating mechanism, the speed of temperature control of the heating mechanism can be improved. As a result, the temperature information output circuit can be corrected for the temperature information signal corresponding to the temperature of the printhead in a short time.

[0279] In one embodiment of the aforementioned liquid ejection device

[0280] The heating mechanism may also have a medium heating function to dry the medium.

[0281] According to this liquid ejection device, there is no need to set up a new structure as a heating mechanism, and the liquid ejection device can be miniaturized.

[0282] In one embodiment of the aforementioned liquid ejection device

[0283] In the direction in which the liquid is ejected from the nozzle, the heating mechanism may also be located at a position that overlaps with at least a portion of the printhead.

[0284] According to this liquid ejection device, by placing the head temperature detection unit in the printhead and the unit temperature detection circuit in the head unit including the printhead near the heating mechanism, the temperature change of the heating mechanism can be detected with high precision. As a result, the correction accuracy of the temperature information output circuit for the temperature information signal corresponding to the temperature of the printhead is further improved.

[0285] In one embodiment of the aforementioned liquid ejection device

[0286] The printhead may also include a nozzle plate on which the nozzles are formed, wherein the shortest distance between the nozzle plate and the heating mechanism is less than 1 mm.

[0287] According to this liquid ejection device, by placing the head temperature detection unit in the printhead and the unit temperature detection circuit in the head unit including the printhead near the heating mechanism, the temperature change of the heating mechanism can be detected with high precision. As a result, the correction accuracy of the temperature information output circuit for the temperature information signal corresponding to the temperature of the printhead is further improved.

[0288] In one embodiment of the aforementioned liquid ejection device

[0289] The head temperature detection unit may also have platinum wiring disposed on the surface of the vibrating plate on the other side of the stacking direction.

[0290] Platinum exhibits a large temperature-dependent resistance change, and also demonstrates high stability and accuracy. Furthermore, the linearity of the resistance change with temperature is also high. According to this liquid ejection device, by incorporating platinum wiring as the head temperature detection unit, the temperature detection accuracy in the head temperature detection unit is further improved.

Claims

1. A liquid ejection device, characterized in that, have: The head unit ejects liquid into the medium based on a drive signal; and Fever-inducing institutions The head unit has: The printhead ejects liquid based on the drive signal; The unit temperature detection circuit detects the temperature of the head unit as unit temperature information and outputs a unit temperature signal including the unit temperature information. as well as The temperature information output circuit receives the unit temperature signal and a head temperature signal, which includes head temperature information corresponding to the temperature of the print head, and outputs a temperature information signal. The printhead includes: A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode and receives the driving signal to drive it. The vibrating plate is located on one side of the piezoelectric element in the stacking direction and is deformed by the piezoelectric element. A pressure chamber substrate, located on one side of the vibrating plate in the stacking direction, is provided with a pressure chamber whose volume varies according to the deformation of the vibrating plate; A nozzle that ejects liquid according to changes in the volume of the pressure chamber; and The head temperature detection unit, located on the opposite side of the vibrating plate in the stacking direction, detects the head temperature information corresponding to the temperature of the pressure chamber and outputs it as the head temperature signal. The temperature information output circuit corrects the head temperature information, which is output as a temperature information signal, based on the unit temperature information and the head temperature information input when the heating mechanism heats at a specified temperature. The temperature information output circuit will retain the unit temperature information contained in the unit temperature signal input at startup, i.e., when the heating mechanism is heating at a specified temperature, as the reference unit temperature information. The head temperature information included in the head temperature signal input at startup, i.e., when the heating mechanism heats up at the specified temperature, will be retained as the reference head temperature information. Based on the reference unit temperature information and the reference head temperature information, the head temperature information contained in the head temperature signal input when the liquid is ejected from the print head is corrected and output as the temperature information signal.

2. A liquid ejection device, characterized in that, have: The head unit ejects liquid into the medium based on a drive signal; and Fever-inducing institutions The head unit has: The printhead ejects liquid based on the drive signal; The unit temperature detection circuit detects the temperature of the head unit as unit temperature information and outputs a unit temperature signal including the unit temperature information. as well as The temperature information output circuit receives the unit temperature signal and a head temperature signal, which includes head temperature information corresponding to the temperature of the print head, and outputs a temperature information signal. The printhead includes: A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode and receives the driving signal to drive it. The vibrating plate is located on one side of the piezoelectric element in the stacking direction and is deformed by the piezoelectric element. A pressure chamber substrate, located on one side of the vibrating plate in the stacking direction, is provided with a pressure chamber whose volume varies according to the deformation of the vibrating plate; A nozzle that ejects liquid according to changes in the volume of the pressure chamber; and The head temperature detection unit, located on the opposite side of the vibrating plate in the stacking direction, detects the head temperature information corresponding to the temperature of the pressure chamber and outputs it as the head temperature signal. The temperature information output circuit corrects the head temperature information, which is output as a temperature information signal, based on the unit temperature information and the head temperature information input when the heating mechanism heats at a specified temperature. The temperature information output circuit retains the unit temperature information contained in the unit temperature signal input when the heating mechanism heats at a first temperature, which is the specified temperature, as the first reference unit temperature information. The head temperature information contained in the head temperature signal input when the heating mechanism heats up at the first temperature is retained as the first reference head temperature information. The unit temperature information contained in the unit temperature signal input when the heating mechanism heats at a second temperature, which is the specified temperature, is retained as the second reference unit temperature information. The head temperature information contained in the head temperature signal input when the heating mechanism heats up at the second temperature is retained as the second reference head temperature information. The correction function is calculated based on the maintained temperature information of the first reference unit, the second reference unit, the first reference head, and the second reference head. The correction function is used to correct the head temperature information contained in the head temperature signal input when the liquid is ejected from the printhead, and the correction is output as the temperature information signal.

3. The liquid ejection device according to claim 1 or 2, characterized in that, The heating mechanism includes a ceramic heater.

4. The liquid ejection device according to claim 1 or 2, characterized in that, The heating mechanism has a medium heating function that dries the medium.

5. The liquid ejection device according to claim 4, characterized in that, In the direction in which the liquid is ejected from the nozzle, the heating mechanism is located at a position that overlaps with at least a portion of the printhead.

6. The liquid ejection device according to claim 5, characterized in that, The printhead includes a nozzle plate on which the nozzle is formed, and the shortest distance between the nozzle plate and the heating mechanism is less than 1 mm.

7. The liquid ejection device according to claim 1 or 2, characterized in that, The head temperature detection unit has platinum wiring disposed on the surface of the vibrating plate on the other side of the stacking direction.

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