JP2012061697A - Liquid ejection head, and image forming apparatus - Google Patents

Abstract

It is difficult to manage a bonding temperature when a wiring board and an actuator means are connected by solder bonding, and disconnection, defective bonding, and the like are likely to occur.
An FPC 15 is different from a first metal wiring 151 and a first electric wiring 151 on a base material 150 made of polyimide or the like, apart from wiring electrodes 41 and 42 which are wirings for transmitting a driving signal. A second metal wiring 152 made of metal is formed, and the first and second metal wirings 151 and 152 are joined to the surface of the piezoelectric member 12 by a solder 156 and a metal film 154 provided via an insulating film 153. By measuring the thermoelectromotive force between the first metal wiring 151 and the second metal wiring 152, the temperature of the junction between the piezoelectric member 12 and the FPC 15 can be measured.
[Selection] Figure 5

Description

  The present invention relates to a liquid discharge head and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. An apparatus (for example, an ink jet recording apparatus) is known. This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  In the present application, the “image forming apparatus” of the liquid discharge recording method is an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply It also means that a droplet is landed on a medium). “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials, resins and the like are also included. The term “paper” is not limited to paper, but includes the above-described OHP sheet, cloth, and the like, and means that ink droplets adhere to the recording medium, recording medium, recording paper, recording It is used as a general term for what includes what is called paper. In addition, the “image” is not limited to a planar one, but includes an image given to a three-dimensionally formed image, and an image formed by three-dimensionally modeling a solid itself.

  As the liquid ejection head, a piezoelectric actuator such as a piezoelectric actuator is used as a pressure generating means (actuator means) for generating pressure to pressurize ink, which is a liquid in the liquid chamber, or a thermal actuator such as an electrothermal conversion means is used. And those using electrostatic actuators are known.

  The liquid ejection head includes a head drive circuit (head driver) that selectively outputs a drive signal to drive a plurality of actuator means, and an FPC (flexible) that transmits the drive signal from the head driver to each actuator means. Board, flexible printed cable, flexible wiring board) and the like.

  2. Description of the Related Art Conventionally, there has been known one in which a temperature sensor is mounted on an FPC in order to detect the temperature of liquid to be discharged (Patent Document 1).

JP 2010-131850 A

  By the way, when the connection between the wiring board and the actuator means is performed by solder bonding, since the temperature management at the time of bonding is performed by managing the temperature of the soldering iron, the accurate bonding temperature cannot be measured, There is a problem that disconnection, poor bonding, etc. are likely to occur, and the yield is reduced.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to enable accurate measurement of the temperature of the joint portion between the wiring board and the actuator means.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
Actuator means for generating a pressure for discharging the droplets;
A wiring board on which wiring for transmitting a drive signal to the actuator means is formed,
On the wiring board, apart from the wiring for transmitting the drive signal, a first metal wiring and a second metal wiring formed of a metal different from the first electric wiring are provided,
The first metal wiring and the second metal wiring are joined to a metal film provided on the surface of the actuator means,
The temperature of the actuator means can be measured by measuring the thermoelectromotive force between the first metal wiring and the second metal wiring connected via the metal film.

The liquid discharge head according to the present invention includes:
Actuator means for generating a pressure for discharging the droplets;
A wiring board on which wiring for transmitting a drive signal to the actuator means is formed,
On the wiring board, apart from the wiring for transmitting the drive signal, a first metal wiring and a second metal wiring formed of a metal different from the first electric wiring are provided,
The first metal wiring and the second metal wiring are partially laminated and bonded to each other,
The temperature of the actuator means can be measured by measuring the thermoelectromotive force between the first metal wiring and the second metal wiring.

  Here, the first metal wiring may be formed of the same metal as the wiring that transmits the driving signal.

  The first metal wiring and the second metal wiring may be provided at a plurality of locations with respect to the actuator means.

An image forming apparatus according to the present invention includes:
A liquid ejection head according to the present invention;
Means for measuring the thermoelectromotive force;
Detecting means for detecting the temperature of the actuator means from the measured thermoelectromotive force.

  According to the liquid ejection head according to the present invention, the second metal wiring formed of a metal different from the first metal wiring and the first electric wiring is provided on the wiring board, separately from the wiring for transmitting the drive signal. The first metal wiring and the second metal wiring are joined to the metal film provided on the surface of the actuator means, and the heat between the first metal wiring and the second metal wiring connected via the metal film. Since the temperature of the actuator means can be measured by measuring the electromotive force, the temperature of the joint portion between the wiring board and the actuator means can be accurately measured.

  According to the liquid ejection head according to the present invention, the second metal wiring formed of a metal different from the first metal wiring and the first electric wiring is provided on the wiring board, separately from the wiring for transmitting the drive signal. The first metal wiring and the second metal wiring are partly laminated and bonded to each other, and the temperature of the actuator means is measured by measuring the thermoelectromotive force between the first metal wiring and the second metal wiring. Therefore, it is possible to accurately measure the temperature of the joint portion between the wiring board and the actuator means.

  According to the image forming apparatus of the present invention, the liquid ejection head according to the present invention, the means for measuring the thermoelectromotive force, and the detecting means for detecting the temperature of the actuator means from the measured thermoelectromotive force. Therefore, stable droplet ejection can be performed, and temperature detection during driving of the actuator means can also be performed.

It is a disassembled perspective explanatory drawing of an example of the liquid discharge head to which this invention is applied. It is sectional explanatory drawing which follows the direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head. It is sectional explanatory drawing which follows the nozzle arrangement direction (liquid chamber short direction) of the piezoelectric actuator of the head. It is side explanatory drawing similarly explaining joining with a wiring board (illustrated in the permeation | transmission state). It is front explanatory drawing with which it uses for description of 1st Embodiment of this invention. FIG. 6 is a cross-sectional explanatory view taken along line AA in FIG. 5. It is principal part front explanatory drawing of the piezoelectric actuator with which it uses for description of 2nd Embodiment of this invention. It is the upper surface explanatory drawing similarly seen from the piezoelectric pillar front end side. It is front explanatory drawing with which it uses for description of 3rd Embodiment of this invention. FIG. 10 is a cross-sectional explanatory view taken along line BB in FIG. 9. It is principal part front explanatory drawing of the piezoelectric actuator provided to description of 4th Embodiment of this invention. It is principal part front explanatory drawing of the piezoelectric actuator with which it uses for description of 5th Embodiment of this invention. FIG. 2 is a schematic configuration diagram illustrating an overall configuration of a mechanism unit of an image forming apparatus according to the present invention that includes the liquid ejection head according to the present invention. It is principal part plane explanatory drawing of the mechanism part. It is block explanatory drawing with which it uses for description of the temperature detection part in the apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of a liquid discharge head to which the present invention is applied will be described with reference to FIGS. 1 is an exploded perspective view of the head, FIG. 2 is a cross-sectional view along a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head, and FIG. 3 is a nozzle arrangement direction of piezoelectric actuators of the head. Cross-sectional explanatory drawing along the (liquid chamber short side direction), FIG. 4 is also a side explanatory drawing for explaining the bonding with the wiring board (shown in a transparent state).

  The liquid discharge head includes a flow path substrate (liquid chamber substrate) 1 formed of a SUS substrate, a vibration plate member 2 bonded to the lower surface of the flow path substrate 1, and a nozzle plate 3 bonded to the upper surface of the flow path substrate 1. And a plurality of nozzles 4 for ejecting droplets (liquid droplets) by these, respectively, as a plurality of liquid chambers (pressurized liquid chamber, pressure chamber, Also referred to as a pressure chamber, a flow path, etc.) 6, a fluid resistance portion 7 that also serves as a supply path for supplying ink to the liquid chamber 6, and a communication portion 8 that communicates with the liquid chamber 6 via the fluid resistance portion 7. Ink is supplied from a common liquid chamber 10 formed in a frame member 17 to be described later to the communication portion 8 through a supply port 9 formed in the diaphragm member 2.

  The flow path substrate 1 is configured by bonding a flow path plate 1A and a communication plate 1B. The flow path substrate 1 is formed by etching the SUS substrate using an acidic etchant or machining such as punching (pressing) to open openings such as the communication path 5, the pressurized liquid chamber 6, and the fluid resistance portion 7. Each is formed. As the flow path substrate 1, a silicon substrate or the like can be used.

  The diaphragm member 2 has each vibration region (diaphragm portion) 2a that forms a wall surface corresponding to each liquid chamber 6, and an island-shaped convex portion on the outer side of the vibration region 2a (on the side opposite to the liquid chamber 6). 2b is provided. A piezoelectric actuator 100 including an electromechanical transducer as a driving means (actuator means, pressure generating means) for deforming the vibration region 2a is disposed on the island-shaped convex portion 2b side of the diaphragm member 2.

  This piezoelectric actuator 100 has a plurality of (here, two) laminated piezoelectric members 12 joined to each other by an adhesive 50 on a base member 13, and the grooves 31 are processed in the piezoelectric member 12 by half-cut dicing. A plurality of piezoelectric pillars 12A and 12B are formed in a comb-like shape at a predetermined interval for one piezoelectric member 12. The piezoelectric columns 12A and 12B of the piezoelectric member 12 are the same, but the piezoelectric column that is driven by giving a driving waveform is the driving piezoelectric column 12A, and the piezoelectric column that is used as a simple column without giving the driving waveform is not driven. It is distinguished as the piezoelectric column 12B. Further, the non-driving piezoelectric column 12B at the end of the piezoelectric member 12 is a non-driving piezoelectric column 12Ba formed wide to take out the common electrode to the outside. The upper end surface (joint surface) of the drive piezoelectric column 12 </ b> A is joined to the island-shaped convex portion 2 b of the diaphragm member 2.

  Here, the piezoelectric member 12 is obtained by alternately stacking the piezoelectric material layers 21 and the internal electrodes 22A and 22B. The internal electrodes 22A and 22B are respectively substantially perpendicular to the end face, that is, the diaphragm member 2 of the piezoelectric member 12. By pulling out to the side surface, connecting to the end face electrodes (external electrodes) 23, 24 formed on the side face, and applying a voltage between the end face electrodes (external electrodes) 23, 24, displacement in the stacking direction occurs. Here, the external electrode 23 is used as an individual external electrode (individual electrode), and the external electrode 24 is used as a common external electrode (common electrode). The external electrodes 23 and 24 are formed of a metal film such as Au.

  The piezoelectric member 12 is connected to an FPC 15 as a flexible wiring board for giving a driving signal to the driving piezoelectric column 12A.

  The FPC 15 includes an individual wiring electrode 41 that is a wiring for transmitting a driving signal, which is connected to the individual electrode 23 of the driving piezoelectric column 12A, and a common electrode of the plurality of driving piezoelectric columns 12A taken out to the non-driving piezoelectric column 12Ba at the end. 24 has a common wiring electrode 42 connected to a common common electrode portion 25 connected to 24. The FPC 15 is bonded to the base member 13 in the vicinity of the piezoelectric member 12 with a hot melt adhesive (not shown). The wiring electrodes 41 and 42 of the FPC 15 and the piezoelectric member 12 are soldered. As a heating method, there are a contact heating method using a heater and a non-contact heating method using a laser or the like, but laser bonding is preferable. In this case, the FPC 15 and the piezoelectric member 12 are brought into close contact with a rigid member such as glass. However, it is preferable that the FPC 15 and the piezoelectric member 12 be bonded by a laser while being in close contact by air pressure.

  The nozzle plate 3 is formed from a nickel (Ni) metal plate, and is manufactured by an electroforming method (electroforming). In this nozzle plate 3, nozzles 4 having a diameter of 10 to 35 μm are formed corresponding to the respective liquid chambers 6 and bonded to the flow path plate 1 with an adhesive. A water repellent layer is provided on the droplet discharge side surface (surface in the discharge direction: discharge surface or surface opposite to the liquid chamber 6 side) of the nozzle plate 3.

  Further, a frame member 17 formed by injection molding with an epoxy resin or polyphenylene sulfite is joined to the outer peripheral side of the piezoelectric actuator 100 composed of the piezoelectric member 12, the base member 13, the FPC 15, and the like. The frame member 17 is formed with the common liquid chamber 10 described above, and further, a supply port 19 for supplying a recording liquid from the outside to the common liquid chamber 10 is formed. It is connected to an ink supply source such as an ink cartridge.

  In the liquid ejection head configured as described above, for example, when driven by a pushing method, a drive pulse voltage of 20 to 50 V is selectively applied to the drive piezoelectric column 12A according to an image recorded from a control unit (not shown). As a result, the driving piezoelectric column 12A to which the pulse voltage is applied is displaced to deform the vibration region 2a of the vibration plate member 2 in the direction of the nozzle plate 3, and the liquid chamber 6 changes its volume (volume) in the liquid chamber 6. By pressurizing the liquid, droplets are ejected from the nozzle 4 of the nozzle plate 3. As the liquid droplets are discharged, the pressure in the liquid chamber 6 decreases, and a slight negative pressure is generated in the liquid chamber 6 due to the inertia of the liquid flow at this time. Under this state, the application of voltage to the drive piezoelectric column 12A is turned off, so that the diaphragm 2 returns to the original position and the liquid chamber 6 becomes the original shape, so that further negative pressure is generated. . At this time, ink is filled from the common liquid chamber 10 into the liquid chamber 6, and droplets are ejected from the nozzles 4 in response to the next drive pulse application.

  In addition to the above-described pushing, the liquid ejection head is not limited to the pulling method (a method of releasing the diaphragm 2 from the pulled state and pressurizing it with a restoring force), and the pulling-pushing method (the diaphragm 2 at the intermediate position). It is also possible to drive by pulling from this position and then extruding.

  Next, a first embodiment of the present invention applied to this liquid discharge head will be described with reference to FIGS. 5 is a front explanatory view for explaining the embodiment, and FIG. 6 is a cross-sectional explanatory view taken along the line AA of FIG.

  The FPC 15 which is a wiring board is different from the first metal wiring 151 and the first electric wiring 151 on the base material 150 made of polyimide or the like, apart from the wiring electrodes 41 and 42 which are wirings for transmitting drive signals. A second metal wiring 152 made of metal is formed.

  Examples of the metal forming the first and second metal wirings 151 and 152 include chromel, alumel, iron, copper, nicro, nicrosyl, platinum, platinum rhodium, tungsten rhenium alloy, iridium, iridium rhodium alloy, nichrome, and gold iron. Alloy, gold-cobalt alloy. In this case, the first metal wiring 151 can be formed of the same metal as that of the individual wiring electrode 41 so that the first metal wiring 151 and the individual wiring electrode 41 can be formed in the same process.

  The first and second metal wires 151 and 152 are bonded to the surface of the piezoelectric member 12 serving as the actuator means by a solder 156 and a metal film 154 provided via an insulating film 153. By using the insulating film 153, it is possible to prevent a current for driving the actuator means from flowing through the first and second metal wirings 151 and 152.

  As described above, the first and second metal wirings 151 and 152 are joined to the Au electrode (metal film 154) by the solder 156, so that the two first and second metal wirings 151 and 152 are connected. A thermoelectromotive force due to the Seebeck effect is generated at a portion where the electrical wiring is joined to the metal film 154. Therefore, the difference between the thermoelectromotive force between the first metal wiring 151 and the second metal wiring 152 measures the thermoelectromotive force between the first metal wiring 151 and the second metal wiring 152 through the metal film 154. Therefore, the temperature of the joint portion between the piezoelectric member 12 and the FPC 15 serving as the actuator means can be measured.

  As described above, on the wiring board, apart from the wiring for transmitting the drive signal, the first metal wiring and the second metal wiring formed of a metal different from the first electric wiring are provided. And the second metal wiring is joined to a metal film provided on the surface of the actuator means, and the thermoelectromotive force between the first metal wiring 151 and the second metal wiring 152 is measured via the metal film 154. By adopting a configuration in which the temperature of the actuator means can be measured, the temperature of the joint portion between the wiring board and the actuator means can be accurately measured. As a result, the management of the bonding temperature in the head manufacturing process is facilitated, and the yield can be improved.

Next, a second embodiment of the present invention will be described with reference to FIGS. 7 is an explanatory front view of the main part of the piezoelectric actuator used for the description of the example, and FIG. 8 is an explanatory top view as seen from the distal end side of the piezoelectric column.
In the first embodiment, the configuration in which the first metal wiring 151 is provided separately from the individual wiring electrode 41 has been described. However, as described above, the individual wiring electrode 41 and the first metal wiring 151 can be formed of the same material. Also, the individual wiring electrode 41 and the first metal wiring 151 can be used together. In this case, as shown in FIG. 8, the insulating film 153 in the configuration of FIG. 6 is eliminated, and the external electrode 23 provided for electrical connection on the surface of the piezoelectric column 12A is used as the metal film 154.

  At this time, the second metal wiring 152 formed of a different metal may be provided anywhere as long as it is connected to the first metal wiring 151 via the external electrode 23, but is preferably in the vicinity of the first metal wiring 151. It is preferable to be connected to the metal film. This is because the resistance value of the metal film itself affects the measurement of the thermoelectromotive force as the separation distance increases.

  In view of this, it is preferable to provide the second metal wiring 152 at the position of the adjacent non-driving piezoelectric column 12B as shown in FIG. At this time, since the external electrode 23 provided on the non-driving column piezoelectric column 12B and the external electrode 23 provided on the driving piezoelectric column 12A are not electrically connected to each other, the second metal wiring 152 bends in the vicinity of the tip to form the first metal The wiring 151 is connected to the external electrode 23 of the adjacent driving piezoelectric column 12A to which the wiring 151 is connected. Here, the second metal wiring 152 and the tip of the first metal wiring 151 are connected side by side in the horizontal direction, but the tip of the first metal wiring 151 may be retracted and the tips may be arranged vertically.

  In this case, when the actual piezoelectric pillar 12A is driven, the connection to the thermoelectromotive force measurement circuit on the second metal wiring 152 side is disconnected, and the conductive characteristic of the first metal wiring 151 functioning as the individual wiring electrode 41 is different from that of the individual individual. The difference from the wiring electrode 41 is avoided.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9 is a front explanatory view for explaining the embodiment, and FIG. 10 is a cross-sectional explanatory view taken along the line BB of FIG.
The FPC 15 which is a wiring board is different from the first metal wiring 151 and the first electric wiring 151 on the base material 150 made of polyimide or the like, apart from the wiring electrodes 41 and 42 which are wirings for transmitting drive signals. A second metal wiring 152 made of metal is formed.

  The first metal wiring 151 and the second metal wiring 152 are partially stacked and bonded to each other, and the first metal wiring 151 side is bonded to the metal film 154 with solder 156. An insulating film 153 is interposed between the metal film 154 and the piezoelectric member 12 that is an actuator means.

  As described above, the first and second metal wires 151 and 152 made of different metals are joined to each other, so that a thermoelectromotive force due to the Seebeck effect is generated at the joined portion. Therefore, by measuring the thermoelectromotive force between the first metal wiring 151 and the second metal wiring 152, the temperature of the joint portion between the piezoelectric member 12 that is the actuator means and the FPC 15 can be measured.

  As described above, on the wiring board, apart from the wiring for transmitting the drive signal, the first metal wiring and the second metal wiring formed of a metal different from the first electric wiring are provided. The second metal wiring and the second metal wiring are partly laminated and bonded to each other, and the temperature of the actuator means can be measured by measuring the thermoelectromotive force between the first metal wiring and the second metal wiring. Thereby, the temperature of the junction part of a wiring board and an actuator means can be measured correctly. As a result, the management of the bonding temperature in the head manufacturing process is facilitated, and the yield can be improved.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is an explanatory front view of a main part of a piezoelectric actuator used for explaining the example.
In the above-described third embodiment, the configuration in which the first metal wiring 151 is provided separately from the individual wiring electrode 41 is shown. However, as in the second embodiment, the individual wiring electrode 41 and the first metal wiring 151 are made of the same material. Therefore, the individual wiring electrode 41 and the first metal wiring 151 can also be used together. In this case, the insulating film 153 is eliminated in the configuration of FIG. 10, and the external electrode 23 provided for electrical connection on the surface of the piezoelectric column 12 is used as the metal film 154.

  At this time, the second metal wiring 152 is disposed in the space between the individual wiring electrodes 41 (between the first metal wiring 151 and the individual wiring electrode 41), and the first metal wiring 151 and the second metal wiring are measured at the temperature measurement site. 152 is connected. By doing so, it is not necessary to separately provide a connection space for the second metal wiring 152, and the space is saved.

  In this case, the side connected to the piezoelectric element column 12A is the first metal wiring 151 so that there is no difference in conductive characteristics from the other individual wiring electrodes 41 when the piezoelectric column 12A is actually driven. it can. At this time, it is necessary to disconnect the connection to the thermoelectromotive force measurement circuit on the second metal wiring 152 side, as in the first embodiment.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In addition, FIG. 12 is a principal front explanatory view of a piezoelectric actuator for explaining the example.
In the present embodiment, the fourth embodiment is applied to a plurality of locations of the actuator means. As a result, more accurate management of the bonding temperature can be performed. The second embodiment can be applied to a plurality of locations of the actuator means.

Next, an example of the image forming apparatus according to the present invention including the liquid discharge head according to the present invention will be described with reference to FIGS. FIG. 13 is a schematic configuration diagram for explaining the overall configuration of the mechanism section of the apparatus, and FIG. 14 is an explanatory plan view of the main part of the mechanism section.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and slave guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 221A and 221B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 includes a plurality of recording heads 234 including the liquid ejection head according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). Nozzle rows composed of nozzles are arranged in the sub-scanning direction orthogonal to the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

  The recording head 234 is configured by attaching liquid ejection heads 234a and 234b each having two nozzle rows to one base member, and one nozzle row of one head 234a has a black (K) droplet. The other nozzle row ejects cyan (C) droplets, the other nozzle row of the other head 234b ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. . Note that, here, a two-head configuration is used to eject four color droplets, but a liquid ejection head for each color may be provided.

  The carriage 233 is equipped with sub tanks 235a and 235b (referred to as “sub tank 235” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 234. The sub tank 235 is supplied with ink of each color from the ink cartridge 210 of each color by the supply unit 224 via the supply tube 236 of each color.

  On the other hand, as a paper feeding unit for feeding the paper 242 stacked on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feeding) that separates and feeds the paper 242 one by one from the paper stacking unit 241. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the transport belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 for maintaining and recovering the nozzle state of the recording head 234 is disposed in a non-printing area on one side in the scanning direction of the carriage 233. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge thickened ink. Yes.

  In addition, in the non-printing area on the other side of the carriage 233 in the scanning direction, idle ejection that receives droplets when performing idle ejection that ejects droplets that do not contribute to recording in order to discharge ink that has been thickened during recording or the like. A receiver 288 is disposed, and the idle discharge receiver 288 is provided with an opening 289 along the nozzle row direction of the recording head 234 and the like.

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 247 and pressed against the conveying belt 251 by the leading end pressure roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  Thus, since the image forming apparatus includes the liquid discharge head according to the present invention as a recording head, stable droplet discharge characteristics can be obtained, and a high-quality image can be stably formed.

Next, the temperature detection unit in this image forming apparatus will be described with reference to the block explanatory diagram of FIG.
The thermoelectromotive force measuring unit 601 measures the thermoelectromotive force generated in the thermocouple 600 configured by the first and second metal wirings 151 and 152 described above. The temperature conversion unit 602 converts the thermoelectromotive force measured by the thermoelectromotive force measurement unit 601 into a temperature and outputs the temperature to the main control unit 500 that controls the entire apparatus.

  Here, since the thermoelectromotive force generated in the thermocouple 600 during use of the apparatus corresponds to the temperature of the actuator means, the temperature of the actuator means of the recording head 234 is determined by measuring the thermoelectromotive force and converting the temperature. Can be detected. Therefore, the main control unit 500 can perform more stable droplet discharge by performing control such as changing the voltage of the driving waveform in accordance with the temperature of the actuator means of the head, thereby forming a high-quality image. Will be able to.

  In the above embodiment, a serial type image forming apparatus is described as an example of the image forming apparatus of the present invention. However, the present invention can be similarly applied to a line type image forming apparatus. Further, the present invention can be applied to an image forming apparatus using a liquid other than the narrowly defined ink, a fixing processing liquid, or the like.

DESCRIPTION OF SYMBOLS 1 Flow path plate 2 Vibration plate member 3 Nozzle plate 4 Nozzle 6 Individual liquid chamber 10 Common liquid chamber 12 Piezoelectric member 12A, 12B Piezoelectric column 12Ba Piezoelectric column 13 Base member 15 FPC (wiring board)
DESCRIPTION OF SYMBOLS 23 Individual electrode 24 Common electrode 41 Individual wiring electrode 42 Common wiring electrode 50 Adhesive agent 151 1st metal electrode 152 2nd metal electrode 154 Metal film 233 ... Carriage 234 ... Recording head

Claims (5)

Actuator means for generating a pressure for discharging the droplets;
A wiring board on which wiring for transmitting a drive signal to the actuator means is formed,
On the wiring board, apart from the wiring for transmitting the drive signal, a first metal wiring and a second metal wiring formed of a metal different from the first electric wiring are provided,
The first metal wiring and the second metal wiring are joined to a metal film provided on the surface of the actuator means,
A liquid discharge head characterized in that the temperature of the actuator means can be measured by measuring a thermoelectromotive force between the first metal wiring and the second metal wiring connected via the metal film. . Actuator means for generating a pressure for discharging the droplets;
A wiring board on which wiring for transmitting a drive signal to the actuator means is formed,
On the wiring board, apart from the wiring for transmitting the drive signal, a first metal wiring and a second metal wiring formed of a metal different from the first electric wiring are provided,
The first metal wiring and the second metal wiring are partially laminated and bonded to each other,
The liquid discharge head according to claim 1, wherein the temperature of the actuator unit can be measured by measuring a thermoelectromotive force between the first metal wiring and the second metal wiring.   3. The liquid ejection head according to claim 1, wherein the first metal wiring is formed of the same metal as the wiring that transmits the drive signal. 4.   4. The liquid ejection head according to claim 1, wherein the first metal wiring and the second metal wiring are provided at a plurality of locations with respect to the actuator means. A liquid discharge head according to any one of claims 1 to 4,
Means for measuring the thermoelectromotive force;
An image forming apparatus comprising: a detecting unit configured to detect a temperature of the actuator unit from the measured thermoelectromotive force.

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