JP5116491B2 - Liquid ejection head, image forming apparatus, and piezoelectric actuator - Google Patents

Description

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

  As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, and a complex machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording method using a recording head for discharging ink droplets. . This liquid discharge recording type image forming apparatus ejects ink droplets from a recording head onto a conveyed paper to form an image (recording, printing, printing, and printing are also used synonymously). Serial type image forming device that forms an image by ejecting droplets while the recording head moves in the main scanning direction, and a line type that forms images by ejecting droplets without the recording head moving There is a line type image forming apparatus using a head.

  In the present application, “image forming apparatus” means an apparatus for forming an image by landing ink on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. "Image formation" is not only the application of images with meanings such as characters and figures to the medium, but also the addition of images with no meaning such as patterns to the medium (simply applying droplets to the medium) Also means landing). The “ink” is not limited to the ink, but is used as a general term for all liquids that can perform image formation, such as a recording liquid, a fixing processing liquid, and a liquid. 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.

  As the liquid ejection head, at least a part of wall surfaces of a plurality of liquid chambers arranged corresponding to a plurality of nozzles arranged in parallel to eject ink droplets is formed by a diaphragm, and the diaphragm is formed by a piezoelectric element. A piezoelectric head using a piezoelectric actuator that deforms and changes the volume of a liquid chamber to eject ink droplets is known.

  In such a piezoelectric head, for example, a multilayer piezoelectric element is used, and an FPC (flexible print) is applied to each of an external electrode (also referred to as an end face electrode) that serves as a common electrode with internal electrodes drawn to the end face and an external electrode that serves as an individual electrode. Common electrode wirings and individual electrode wirings of wiring members such as cables) are joined, and a drive signal corresponding to an image signal is given to each piezoelectric element.

  In this case, as a method of electrically connecting the wiring electrode provided on the wiring member such as FPC and the external electrode of the piezoelectric element, for example, a metal is interposed between both electrodes, and both electrodes are made of a laser such as glass. A method in which both electrodes are welded and joined together by melting the metal with a laser beam by bonding with a transmission rigid member, and both electrodes are made of metal by melting the metal by thermocompression bonding such as a heater. A method of welding and joining is known.

For example, Patent Document 1 discloses that a common electrode portion that is electrically connected to each other is provided at outer end portions on both sides of an individual electrode terminal connection portion of an inkjet head and a flexible substrate.
JP 2005-153376 A

In Patent Document 2, a plurality of laminated piezoelectric element members having a plurality of piezoelectric elements are arranged on a base member along the longitudinal direction of the laminated piezoelectric element member, and the piezoelectric elements of each laminated piezoelectric element member are Grooves are formed by leaving the bridging portion without being completely divided, and external electrodes serving as common electrodes are formed on the end surfaces of the non-driving portions at both ends of the piezoelectric element member. It is described to do.
JP 2006-175845 A

  By the way, in order to reduce the junction resistance between the common electrode of the head and the FPC side wiring electrode, it is preferable to increase the bonding area between the common electrode and the FPC side wiring electrode. The width of the piezoelectric element provided with the external electrode is made wider than the width of the individual piezoelectric element (see Patent Document 2).

However, since the common electrode at the end portion is wide, it is necessary to apply a large amount of heat, and there is a problem in that many joint failures occur due to the expansion and contraction of the flexible substrate. In addition, since a large amount of heat is applied to the common electrode at both ends, there is a problem that not only the common electrode part but also the entire flexible substrate including the individual electrode part is easily damaged. Further, since the common electrode at both ends is wide, it is necessary to apply a large amount of heat, and there is a problem that the production efficiency is lowered because the heating time is extended.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce the occurrence of defective bonding between electrodes of a piezoelectric element and a wiring member and damage to the wiring member.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A diaphragm that forms at least a part of a wall surface of a liquid chamber that communicates with a nozzle that discharges droplets;
A plurality of piezoelectric elements that deform the diaphragm, arranged at predetermined intervals; and
The piezoelectric element on one end side of the piezoelectric element array is provided with a plurality of common external electrodes which are common electrodes on one end surface in a direction orthogonal to the direction in which the piezoelectric elements are arranged, and the piezoelectric element provided with the common external electrode Individual external electrodes that serve as individual electrodes are provided for piezoelectric elements other than the elements,
Connected to a common electrode wiring connected to a plurality of common external electrodes of the piezoelectric elements on one end side of the piezoelectric element array, and to individual external electrodes of piezoelectric elements other than the piezoelectric elements provided with the common external electrodes A flexible wiring member provided with the individual electrode wiring,
The width of the branched portion of the common external electrode and the width of the individual external electrode in the piezoelectric element column arrangement direction are the same .

  An image forming apparatus according to the present invention includes the liquid ejection head according to the present invention.

The piezoelectric actuator according to the present invention is
A piezoelectric element array in which a plurality of piezoelectric elements are arranged at predetermined intervals;
The piezoelectric element on one end side of the piezoelectric element array is provided with a plurality of common external electrodes which are common electrodes on one end surface in a direction orthogonal to the direction in which the piezoelectric elements are arranged, and the piezoelectric element provided with the common external electrode Individual external electrodes that serve as individual electrodes are provided for piezoelectric elements other than the elements,
Connected to a common electrode wiring connected to a plurality of common external electrodes of the piezoelectric elements on one end side of the piezoelectric element array, and to individual external electrodes of piezoelectric elements other than the piezoelectric elements provided with the common external electrodes A flexible wiring member provided with the individual electrode wiring ,
The width of the branched portion of the common external electrode and the width of the individual external electrode in the piezoelectric element column arrangement direction are the same .

  According to the liquid ejection head according to the present invention and the piezoelectric actuator according to the present invention, the piezoelectric element on one end side of the piezoelectric element array is branched into a plurality of common electrodes on one end surface in a direction orthogonal to the direction in which the piezoelectric elements are arranged. Since the common external electrode is provided, the overall area of the common external electrode can be increased without increasing the width of the common external electrode connected to the wiring member. Occurrence of poor bonding and damage to the wiring member can be reduced.

  According to the image forming apparatus of the present invention, since the liquid discharge head with reduced bonding failure and damage to the wiring member is provided, stable image formation can be performed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of a liquid discharge head including a piezoelectric actuator according to the present invention will be described with reference to FIGS. 1 is an exploded perspective view of the head, FIG. 2 is a cross-sectional explanatory view along a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head, and FIGS. 3 and 4 are nozzle arrangement directions of the head. It is sectional explanatory drawing of the different example along (liquid chamber transversal direction).

  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.

  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, and upper end surfaces (joint surfaces) of the piezoelectric element columns 12A and 12B of the laminated piezoelectric element member 12 as driving means (actuator means, pressure generating means) for deforming the vibration region 2a on the island-shaped convex portions 2b. Are joined. The lower end surface of the multilayer piezoelectric element member 12 is joined to the base member 13.

  Here, the piezoelectric element member 12 is formed by alternately laminating piezoelectric material layers 21 and internal electrodes 22 a and 22 b, and the internal electrodes 22 a and 22 b are respectively substantially perpendicular to the end face, that is, the diaphragm 2 of the piezoelectric element 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. The piezoelectric element member 12 is formed by forming grooves by half-cut dicing and forming a required number of piezoelectric element columns 12A and 12B in a comb-like shape at a predetermined interval with respect to one piezoelectric element member. In this example, each of the piezoelectric element columns 12A and 12B becomes “a plurality of piezoelectric elements”, and the piezoelectric element member 12 forming these corresponds to the “piezoelectric element row”.

  Note that the piezoelectric element columns 12A and 12B of the piezoelectric element member 12 are the same, but the piezoelectric element column that is driven by giving a driving waveform is used as the piezoelectric element column 12A, and a simple column without giving the driving waveform. The columns are distinguished as piezoelectric element columns 12B. In this case, as shown in FIG. 3, the piezoelectric element columns 12A for driving and the piezoelectric element columns 12B for supporting columns are alternately used, or all the piezoelectric element columns are driven piezoelectrically as shown in FIG. Any of the normal pitch configurations used as the element pillars 12A can be adopted.

  Also, the external electrodes 24 of all the piezoelectric element columns 12A and 12B are electrically connected in common, and the plurality of piezoelectric element columns 12B on one end side of the piezoelectric element member 12 (piezoelectric element array) are arranged on the external electrode 23 side. A common external electrode 25 (see FIG. 6 described later), which is an external electrode (end surface electrode) serving as a common electrode provided on the end face, is connected via internal electrodes 22a and 22b.

  Then, the individual external electrode 23 of each driving piezoelectric element column 12A of the piezoelectric element member 12 is directly connected to the individual electrode wiring of the FPC 15 as a flexible wiring member with a solder member in order to give a driving signal, The common external electrode 25 provided on the plurality of piezoelectric element columns 12B on the one end side of the piezoelectric element member 12 is connected to the common electrode wiring of the FPC 15. The FPC 15 is bonded to the base member 13 with a hot melt adhesive 16 in the vicinity of the piezoelectric element member 12.

  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.

  This head is configured to pressurize the ink in the liquid chamber 6 by using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element member 12, and the droplet discharge direction is the flow direction of the recording liquid in the liquid chamber 6. The side shooter method is different from that of droplets. By adopting the side shooter system, the size of the piezoelectric element member 12 becomes approximately the size of the head, and the miniaturization of the piezoelectric element member 12 can be directly linked to the miniaturization of the head, and the head can be easily miniaturized.

  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 actuator portion composed of the piezoelectric element 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 discharge head configured as described above, for example, when driven by a punching method, a driving pulse voltage of 20 to 50 V is selectively applied to the driving piezoelectric element column 12A according to an image recorded from a control unit (not shown). Is applied to the piezoelectric element column 12A to which the pulse voltage is applied, and the vibration region 2a of the vibration plate 2 is deformed in the direction of the nozzle plate 3, and the liquid chamber 6 changes its volume (volume). A liquid droplet is discharged from the nozzle 4 of the nozzle plate 3 by pressurizing the liquid. 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, when the voltage application to the piezoelectric element column 12A is turned off, 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, the recording liquid 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 connection structure between the piezoelectric element (column) constituting the piezoelectric actuator according to the present invention and the FPC in the liquid discharge head will be described with reference to FIGS. 5 is a schematic explanatory view along a direction orthogonal to the nozzle arrangement direction of the piezoelectric actuator, FIG. 6 is a perspective illustration of the main part, FIG. 7 is a schematic explanatory view along the nozzle arrangement direction of the piezoelectric actuator, and FIG. FIG. 3 is a schematic explanatory view along the nozzle arrangement direction of the piezoelectric actuator. Here, the piezoelectric element columns of the piezoelectric element member 12 are shown in a normal pitch configuration that is used as the driving piezoelectric element column 12A except for the two piezoelectric element columns 12B at one end.

  Here, in the piezoelectric element member 12, a plurality of (two in this case) piezoelectric element columns on one end side of the piezoelectric element columns are used as the supporting piezoelectric element columns 12 </ b> B, and the other piezoelectric element columns are used as driving piezoelectric elements. The element column 12A is used. The external electrodes (end surface electrodes) provided on one end surface of the support piezoelectric element column 12B in the direction orthogonal to the direction in which the piezoelectric element columns are arranged are common external electrodes 25 and 25 serving as common electrodes, and other driving piezoelectric elements. The individual electrode (end surface electrode) provided on one end surface in the direction orthogonal to the piezoelectric element column arrangement direction of the column 12A is used as the individual external electrode 23 serving as an individual electrode.

  As described above, one common external electrode 25 and individual external electrode 23 are formed simultaneously with the piezoelectric element columns 12A and 12B by groove processing by half-cut dicing, and the width in the direction in which the piezoelectric element columns are arranged is the same.

  The common external electrode (end face electrode) 25 of the two piezoelectric element columns 12B on one end side of the piezoelectric element member 12 and the common electrode wiring (connection electrode) 31B of the FPC 15 are solder provided on the common electrode wiring 31B of the FPC 15. It is electrically connected by being directly joined by the member 32. Further, the individual external electrode (end face electrode) 23 of the other piezoelectric element column 12A of the piezoelectric element member 12 and the individual electrode wiring (connection electrode) 31A of the FPC 15 are directly joined by the solder member 32 provided on the individual electrode wiring 31B of the FPC 15. By being electrically connected.

  In order to join the individual external electrode 23 and the common external electrode 25 of the piezoelectric element member 12 and the connection electrodes (individual electrode wiring and common electrode wiring) 31A and 31B of the FPC 15, the FPC 15 including the connection electrodes 31A and 31B and a resin member. This is performed by melting the solder member 32 by irradiation with a laser beam that can transmit through or thermocompression bonding with a heater.

  The solder member 32 may be any material that has a lower melting point than the connection electrode 31 made of a metal member and the FPC 15 made of a resin material and is made of a conductive material. Pb) is preferably not contained. For example, a solder mainly composed of tin (Sn) and bismuth (Bi) can be used as the solder member 32. Since lead is not contained, it is effective from the viewpoint of environmental protection, and the solder member 32 mainly composed of tin (Sn) and bismuth (Bi) has a very low melting point among non-lead members. Therefore, the electrode 31 and the external electrode 23a can be easily welded without damaging the FPC 15 and the piezoelectric element 12.

  Here, although FPC is used as the wiring member, it may be any film provided with a plurality of electrodes that are thin and parallel to each other. For example, TAB (Tape Automated Bonding) can also be used. .

  Thus, two or more piezoelectric elements (piezoelectric element columns in the above embodiment) on one end side of the piezoelectric element array are provided with a common external electrode serving as a common electrode on one end face in a direction orthogonal to the direction in which the piezoelectric elements are arranged. Therefore, the overall area of the common external electrode can be widened without increasing the width of the common external electrode connected to the wiring member, and the bonding failure between the electrodes of the piezoelectric element and the wiring member can occur. Damage can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS. 9 is a schematic explanatory diagram along the nozzle arrangement direction of the piezoelectric actuator, and FIG. 10 is a schematic explanatory diagram along the nozzle arrangement direction of the piezoelectric actuator.
Here, the piezoelectric element column 12Ba on one end side of the piezoelectric element member 12 is formed wider than the other piezoelectric element columns 12A in the direction in which the piezoelectric element columns are arranged. Here, two common external electrodes 25a and 25b are formed. These common external electrodes 25a and 25b are connected by a bridging portion 25c, and the width of the common external electrodes 25a and 25b in the direction in which the piezoelectric element columns are arranged is the same as the width of the individual external electrodes 23 of the other piezoelectric element columns 12A. ing.

  The two branched common external electrodes (end face electrodes) 25a and 25b on one end side of the piezoelectric element member 12 are electrically connected independently of the common electrode wiring (connection electrode) 31B of the FPC 15.

  As described above, the piezoelectric element on one end side of the piezoelectric element array is provided with a plurality of common external electrodes that are branched into a common electrode on one end surface in a direction orthogonal to the direction in which the piezoelectric elements are arranged. The overall area of the common external electrode can be increased without increasing the width of the common external electrode to be connected, and the occurrence of defective bonding between the electrodes of the piezoelectric element and the wiring member and the damage to the wiring member can be reduced. it can.

Next, an example of a wiring member joining apparatus for joining a wiring means such as an FPC and a piezoelectric element will be described with reference to a schematic configuration diagram of FIG.
This wiring member joining apparatus 100 electrically joins and connects a plurality of parallel first electrodes provided on a thin film-like first wiring member and a plurality of parallel second electrodes provided on a second wiring member. To do. In the following description, FIG. 11 is a height direction Z-axis direction when viewed from the front, a plane orthogonal to the height direction is the XY plane, and a width direction (lateral direction) when FIG. 11 is viewed from the front is the Y-axis direction.

  In the wiring member joining apparatus 10, the base 111 is provided with a first member holding mechanism 112, a second member holding mechanism 113, a laser irradiation mechanism 114, a camera 115, and an air path forming mechanism 116. The drive is controlled centrally by a control mechanism (not shown).

  The first member holding mechanism 112 includes a joining XY direction adjusting unit 117 provided on the base 111, a joining Z-axis direction adjusting unit 118 attached thereto, and an adjusting stage 119 attached thereto. The joining XY direction adjusting unit 117 includes an X-axis drive unit that is supported by a guide shaft that extends in the X-axis direction (not shown) and a Y-axis that is supported by a guide shaft that extends in the Y-axis direction. The driving unit is configured to be movable along the XY plane. A joining Z-axis direction adjusting unit 118 is attached to the joining XY direction adjusting unit 117 so as to be movable together with the joining XY direction adjusting unit 117.

  The bonded Z-axis direction adjusting unit 118 is configured to be freely movable along the Z-axis direction with respect to the bonded XY direction adjusting unit 117. In other words, the joint XY direction adjusting unit 117 and the joint Z axis direction adjusting unit 118 can be moved to a desired position so as to be movable together with the joint Z axis direction adjusting unit 118. In addition, an adjustment stage 119 is attached to the bonding Z-axis direction adjustment unit 118.

  The adjustment stage 119 is a plate-like member provided so as to extend along the XY plane at the upper end position of the bonding Z-axis direction adjustment unit 118. An upper surface (119a) along the XY plane of the adjustment stage 119 serves as a mounting surface 119a for the first wiring member (the FPC 15 described above), and a plurality of positioning pins 120 (only one is shown in FIG. 11) protruding from this surface. And the first wiring member (FPC 15) placed on the placement surface 119a can be sucked and held. Each positioning pin 120 roughly determines the mounting position of the first wiring member (FPC 15) mounted on the mounting surface 119a of the adjustment stage 119.

  With the configuration described above, the first member holding mechanism 112 has a desired position in a state in which the first wiring member (FPC 15) sucked and held on the mounting surface 119a of the adjustment stage 119 extends along the XY plane. Can be adjusted. A second member holding mechanism 113 is provided to fix and hold the second wiring member (piezoelectric element member 12) joined to the first wiring member (FPC 15).

  The second member holding mechanism 113 has a second member mounting table 122 attached to a fixed table 121 provided on the base 111, and a second wiring member mounted on the second member mounting table 122. Can be adsorbed and held (here, the piezoelectric element member 12 as the second wiring member attached thereto is fixed via the base member 13). The second member holding mechanism 113 is a first wiring member (which is sucked and held in a state of being approximately positioned by the first member holding mechanism 112 above the joint portion of the second wiring member (piezoelectric element member 12) sucked and held. The relative positional relationship with the first member holding mechanism 112 is set so that the joint portion of the FPC 15) is located. A laser irradiation mechanism 14 is provided in order to irradiate the joint with laser light.

  The laser irradiation mechanism 114 is attached to the base 111 so as to be always fixed at a fixed position via the mounting arm 123, and includes a laser XY direction adjustment unit 124, a laser Z axis direction adjustment unit 125, and a laser irradiation unit. 126.

  Although not shown, the laser XY direction adjusting unit 124 is supported by an X-axis driving unit supported to be driven by a guide shaft extending in the X-axis direction and a guide shaft extending by the Y-axis direction. It is comprised by the Y-axis drive part, and is movable along an XY plane. A laser Z-axis direction adjusting unit 125 is attached to the laser XY direction adjusting unit 124 so as to be movable together with the laser XY direction adjusting unit 124.

  Although not shown, the laser Z-axis direction adjustment unit 125 is configured so as to be freely accessible along the Z-axis direction with respect to the laser XY direction adjustment unit 124. It is possible to move together with the laser Z-axis direction adjusting unit 125, that is, to move to a desired position on the base 111 by the laser XY direction adjusting unit 124 and the laser Z-axis direction adjusting unit 125. The laser irradiation unit 126 is attached to the laser Z-axis direction adjustment unit 125.

  The laser irradiation unit 126 can emit laser light L, and a semiconductor laser is employed. The laser irradiation unit 126 is capable of emitting the laser beam L along the Z-axis direction regardless of the position moved by the laser XY direction adjusting unit 124 and the laser Z-axis direction adjusting unit 125. Is attached. For this reason, the laser irradiation mechanism 114 functions as an irradiation unit.

  A camera 115 is provided so as to be positioned between the laser irradiation unit 126 and the second wiring member (piezoelectric element member 12) held by suction by the second member holding mechanism 113. Although not shown, the camera 115 is positioned on the optical axis of the laser light L emitted from the laser irradiation unit 126 regardless of the movement of the laser irradiation unit 126 (for example, interlocked with the laser irradiation unit 126). So as to be fixed to the laser Z-axis direction adjusting portion 125). For this reason, the camera 115 can image the vicinity of the irradiation region of the laser light L without obstructing the irradiation of the laser light L by the laser irradiation unit 126. The air path forming mechanism 116 holds the air path forming plate 127 between the camera 115 and the second wiring member (piezoelectric element 12) sucked and held by the second member holding mechanism 113.

  The air path forming mechanism 116 includes an air path XY direction adjusting unit 128 and an air path forming plate 127. Although not shown, the air passage XY direction adjusting unit 128 is supported by an X-axis driving unit supported to be driven by a guide shaft extending in the X-axis direction and a guide shaft extending by the Y-axis direction. The Y-axis driving unit is movable along the XY plane. An air path forming plate 127 is detachably fixed and held on the air path XY direction adjusting unit 128 so as to be movable together with the air path XY direction adjusting unit 128.

  As will be described later, the air path XY direction adjusting unit 128 includes an air path forming plate 127 having a plate shape as a whole extending along the XY plane, and the laser beam L emitted from the laser irradiation unit 126 and the laser beam L The air path forming plate 127 is fixedly held so that the optical axis of the coincident camera 115 vertically cuts the inside of the laser transmitting plate portion 141 and the air path forming notch portion 143 provided on the air path forming plate 127. . Further, the air path XY direction adjusting unit 128 moves the air path forming plate with respect to the laser beam L and the optical axis of the camera 115 when the laser irradiation unit 126 is moved by the laser XY direction adjusting unit 124 and the laser Z axis direction adjusting unit 125. 127 is configured to be interlocked with the position of the laser irradiation unit 126 so that the positional relationship of 127 is maintained. Accordingly, the laser light L emitted from the laser irradiation unit 126 passes through the air path forming plate 127 regardless of the position of the laser irradiation unit 126 to be moved, and the first wiring member (FPC15) and the second wiring member. A joint portion with the (piezoelectric element member 12) can be irradiated.

  Here, a semiconductor laser is used as the laser beam, but since it is inexpensive and easy to control, the joining operation can be performed inexpensively and appropriately. Further, since the semiconductor laser has a high transmittance to the resin material, the connection electrodes 31A and 31B and the outside are not damaged without damaging the FPC 15 (first wiring member) and the piezoelectric element member 12 (second wiring member). The electrodes 23 and 25 can be appropriately joined.

  In addition, although a semiconductor laser is used as the laser irradiation unit 126, the absorption rate to the portion (the solder member 32 described above) irradiated for bonding is good, and the transmittance of the first wiring member (FPC 15) is good. For example, a YAG (Yttrium / Aluminum / Garnet) laser emitted continuously may be used, and the present invention is not limited to the above-described embodiments.

  Here, the bonding is performed using a laser. However, this bonding may be performed using a thermocompression bonding tool such as a heater chip, and in this case, the same effect on bonding failure can be expected.

Next, an example of an image forming apparatus equipped with the liquid ejection head according to the present invention will be described with reference to FIGS.
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 sub guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 201A and 201B. 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 has recording heads 234a and 234b (which are composed of liquid ejection heads according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). When not distinguished, it is referred to as “recording head 234”). A nozzle row composed of a plurality of nozzles is arranged in the sub-scanning direction orthogonal to the main scanning direction, and is mounted with the ink droplet ejection direction facing downward.

  Each of the recording heads 234 has two nozzle rows. One nozzle row of the recording head 234a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 234b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. In this example, four-color droplets are ejected in a two-head configuration. However, a recording head for each color can be provided, and a nozzle row in which a plurality of nozzles ejecting four-color droplets are arranged. It is also possible to have a single recording head configuration.

  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 that is a head maintenance / recovery device according to the present invention includes a recovery means for maintaining and recovering the nozzle state of the recording head 234 in the non-printing area on one side of the carriage 233 in the scanning direction. Is arranged. 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 for discharging the liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing.

  In addition, in the non-printing area on the other side in the scanning direction of the carriage 233, the liquid that receives liquid droplets when performing idle ejection that ejects liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An ink recovery unit (empty discharge receiver) 288 that is a recovery container is disposed, and the ink recovery unit 288 includes 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 237 and pressed against the conveying belt 251 by the leading end pressing 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.

  As described above, since the image forming apparatus includes the liquid ejection head according to the present invention, there is no bonding failure, the reliability of the recording head is improved, and stable recording can be performed.

  In the above embodiment, the present invention has been described with reference to an example in which the present invention is applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this. For example, the present invention may be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. it can. 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.

FIG. 3 is an exploded perspective view illustrating an example of a liquid discharge head according to the first embodiment of the present invention. It is sectional explanatory drawing along the liquid chamber longitudinal direction of the head. It is sectional explanatory drawing of the bipitch structure along the liquid chamber transversal direction of the head. It is sectional explanatory drawing of the normal pitch structure along the liquid chamber transversal direction of the head. It is a typical explanatory view along the direction orthogonal to the nozzle arrangement direction of the piezoelectric actuator. Is a perspective view of the main part. It is typical explanatory drawing which follows the nozzle arrangement direction of a piezoelectric actuator. It is a typical explanatory view which follows the nozzle arrangement direction of a piezoelectric actuator similarly. FIG. 6 is a schematic explanatory diagram along a nozzle arrangement direction of piezoelectric actuators in a liquid ejection head according to a second embodiment of the present invention. It is a typical explanatory view which follows the nozzle arrangement direction of a piezoelectric actuator similarly. It is a typical block diagram explaining an example of a wiring member joining apparatus. 1 is an overall configuration diagram illustrating an example of an image forming apparatus according to the present invention. Similarly it is principal part plane explanatory drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Channel plate 2 ... Nozzle plate 3 ... Vibration plate 4 ... Nozzle 6 ... Individual liquid chamber 10 ... Common liquid chamber 12 ... Piezoelectric element member 12A, 12B ... Piezoelectric element column 13 ... Base member 15 ... FPC (wiring member)
23 ... Individual external electrode 25 ... Common external electrode 31A ... Individual electrode wiring (connection electrode)
31B ... Common electrode wiring (connection electrode)
32 ... Solder member 234 ... Carriage 235 ... Recording head

Claims (3)

A diaphragm that forms at least a part of a wall surface of a liquid chamber that communicates with a nozzle that discharges droplets;
A plurality of piezoelectric elements that deform the diaphragm, arranged at predetermined intervals; and
The piezoelectric element on one end side of the piezoelectric element array is provided with a plurality of common external electrodes which are common electrodes on one end surface in a direction orthogonal to the direction in which the piezoelectric elements are arranged, and the piezoelectric element provided with the common external electrode Individual external electrodes that serve as individual electrodes are provided for piezoelectric elements other than the elements,
Connected to a common electrode wiring connected to a plurality of common external electrodes of the piezoelectric elements on one end side of the piezoelectric element array, and to individual external electrodes of piezoelectric elements other than the piezoelectric elements provided with the common external electrodes A flexible wiring member provided with the individual electrode wiring,
The liquid discharge head according to claim 1 , wherein a width of the branched portion of the common external electrode and the width of the individual external electrode in the piezoelectric element column arrangement direction are the same . An image forming apparatus comprising the liquid discharge head according to claim 1 . A piezoelectric element array in which a plurality of piezoelectric elements are arranged at predetermined intervals;
The piezoelectric element on one end side of the piezoelectric element array is provided with a plurality of common external electrodes which are common electrodes on one end surface in a direction orthogonal to the direction in which the piezoelectric elements are arranged, and the piezoelectric element provided with the common external electrode Individual external electrodes that serve as individual electrodes are provided for piezoelectric elements other than the elements,
Connected to a common electrode wiring connected to a plurality of common external electrodes of the piezoelectric elements on one end side of the piezoelectric element array, and to individual external electrodes of piezoelectric elements other than the piezoelectric elements provided with the common external electrodes A flexible wiring member provided with the individual electrode wiring ,
The piezoelectric actuator characterized in that the branched portion of the common external electrode and the width of the individual external electrode in the direction of arranging the piezoelectric element columns are the same .

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