JP2009178969A - Liquid ejection head and image forming apparatus - Google Patents

Abstract

When a whole surface is bonded with a conductive adhesive to make electrical connection between a piezoelectric element and a base member, it is difficult to ensure assembly ease and bonding strength.
A piezoelectric element member 2 formed by arranging a plurality of piezoelectric element columns 12 is bonded to a conductive base member 3 via an adhesive layer 4 so that the piezoelectric element member 2 is connected to the base member 3 of the piezoelectric element member 2. A common electrode 23b common to the plurality of piezoelectric element columns 12 is provided on the joint surface, and the adhesive layer 4 on the joint surface contains conductive particles, and a first region that conducts the common electrode 23b and the base member 4 electrically. 41 and a second region 42 that does not contain conductive particles.
[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 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 discharges droplets from a recording head onto a conveyed paper to form an image (recording, printing, printing, and printing are also synonymous). 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 a liquid discharge head, a piezoelectric element member in which a plurality of piezoelectric element columns are arranged is used as an adhesive layer on a base member as pressure generating means (actuator means) for generating pressure to pressurize ink that is liquid in a liquid chamber. There is known a piezoelectric head using a piezoelectric actuator joined via a wire.

  As described above, in the liquid discharge head using a plurality of piezoelectric elements, as a method of taking out the common electrode common to the plurality of piezoelectric elements, the common electrode (COM line) is drawn out to the same surface as the joint surface of the power feeding member such as an FPC. Is generally adopted.

Further, as described in Patent Document 1, it is known to join a piezoelectric element member to a base member made of metal by an anaerobic adhesive that starts polymerization by metal ions.
Japanese Patent Laid-Open No. 2003-21658

In addition, as described in Patent Document 2, it is also known that an anaerobic curable insulating adhesive contains conductive particles to bond a piezoelectric element and a substrate.
JP-A-10-315485

  As described above, according to the configuration in which the common electrode (COM line) is drawn out to the same surface as the joint surface of the power supply member such as the FPC, the length of the piezoelectric element member is longer than the actual driving region or the height is high. This increases the size and cost of the piezoelectric actuator. In order to realize a long head and a compact line, it is clear that it is better to arrange the piezoelectric element members in a straight line rather than arranging a plurality of heads. Since the entire length of the member becomes the drive region, there is a problem that it is difficult to pull out the COM line.

  Also, when a conductive adhesive is used such as a structure in which the piezoelectric element member and the base member for fixing the piezoelectric element member are bonded with a conductive adhesive and the COM line is drawn from the base member, it is necessary to apply heat. Therefore, there is a problem that separation of the joint portion occurs due to the difference in linear expansion coefficient, or it is difficult to maintain the positional relationship between the piezoelectric element member and the base member.

  Furthermore, in the case of an actuator configuration in which a plurality of piezoelectric element members are arranged in a straight line on one base member, the position between the piezoelectric element members needs to be managed with high accuracy. It is preferable that can be cured immediately.

  In the configuration described in Patent Document 1, since conductive particles are contained in the entire bonding surface, even if the adhesive on the portion protruding from the bonding surface (the portion in contact with air) is irradiated with ultraviolet rays. Furthermore, since the conductive particles shield ultraviolet rays and only the outermost surface is cured, there is a problem that temporary bonding cannot be performed.

  The present invention has been made in view of the above-described problems, and an object thereof is to make electrical connection between a piezoelectric element and a base member, easy assembly, and securing of bonding strength.

In order to solve the above problems, the piezoelectric actuator according to the present invention is:
A piezoelectric element member formed by arranging a plurality of piezoelectric element columns is bonded to a conductive base member via an adhesive layer,
A common electrode common to the plurality of piezoelectric element columns is provided on a joint surface of the piezoelectric element member with the base member,
The adhesive layer on the joint surface includes conductive particles, and includes a first region that conducts the common electrode and the base member, and a second region that does not include the conductive particles.

  Here, the first region is surrounded by the second region, and the first region is sandwiched between the second regions at both ends in the direction orthogonal to the arrangement direction of the piezoelectric element columns. Alternatively, the first region may be configured such that both end sides in the arrangement direction of the piezoelectric element columns are sandwiched between the second regions. Moreover, it can be set as the structure by which the said several piezoelectric element member was joined to one said base member. In addition, the conductive particles can be configured to be silver, and the conductive particles can be configured to have a mixture of spherical and flaky particles.

The liquid discharge head according to the present invention includes:
A flow path member that forms a plurality of liquid chambers each communicating with a plurality of nozzles that discharge droplets;
A diaphragm member forming at least one wall surface of the liquid chamber;
A piezoelectric actuator for deforming the diaphragm member,
The piezoelectric actuator is a piezoelectric actuator according to any one of claims 1 to 7.

  The image forming apparatus according to the present invention includes the liquid discharge head according to the present invention.

  According to the piezoelectric actuator of the present invention, a piezoelectric element member formed by arranging a plurality of piezoelectric element columns is joined to a conductive base member via an adhesive layer, and the piezoelectric element member is connected to the base member of the piezoelectric element member. A common electrode common to the plurality of piezoelectric element columns is provided on the bonding surface, and the adhesive layer on the bonding surface contains conductive particles, a first region for conducting the common electrode and the base member, and conductive particles Since the piezoelectric element and the base member can be electrically connected in the first region, the piezoelectric element member and the base member can be easily joined in the second region. It can be secured and bonded.

  According to the liquid ejection head according to the present invention, since the piezoelectric actuator according to the present invention is provided, a compact and long head can be obtained.

  According to the image forming apparatus of the present invention, since the liquid ejection head according to the present invention is provided, a long head can be provided to achieve high-speed recording.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of a piezoelectric actuator according to the present invention will be described with reference to FIGS. 1 is a schematic front view of the piezoelectric actuator, FIG. 2 is a side view of FIG. 1, FIG. 3 is an enlarged side cross-sectional view of the piezoelectric element member, and FIG. 4 is an enlarged view of portion A of FIG. FIG. 5 and FIG. 5 are plan explanatory views of FIG.

  The piezoelectric actuator 1 is configured by joining two piezoelectric element members 2 and 2 to a conductive base member 3 via an adhesive layer 4. The piezoelectric element member 2 is formed in a comb-like shape (see FIG. 4), but the illustration is simplified in FIG. 1 (the same applies to the following drawings).

  As shown in FIG. 4, the piezoelectric element member 2 is formed with a required number of piezoelectric element columns 12 arranged by grooving by half-cut dicing. As shown in FIG. 3, the piezoelectric element member 2 is formed by alternately laminating piezoelectric material layers 21 such as PZT and internal electrodes 22a and 22b. The internal electrodes 22a and 22b are respectively drawn out to the end faces. The individual end face electrode (external electrode) 23 a and the common end face electrode (external electrode) 23 b formed on the end face are connected to the common end face electrode (external electrode) 23 b, respectively. A sign of “23b1” is attached to the bonding surface portion.), And a voltage is applied between these end face electrodes (external electrodes) 23a and 23b, thereby causing displacement in the stacking direction.

  As shown in FIGS. 2 and 5, the adhesive layer 4 includes a first region 41 made of an ultraviolet (UV) anaerobic adhesive to which conductive particles are added, and a UV anaerobic adhesion to which no conductive particles are added. And a second region 42 made of an agent layer. Here, the second region 42 is a region corresponding to the outside in the direction orthogonal to the arrangement direction of the piezoelectric element columns 12 of the two piezoelectric element members 2, and the first region 41 is the two piezoelectric element members 2. It is provided in each of the regions corresponding to the inside of the direction orthogonal to the arrangement direction of the piezoelectric element columns 12.

  The base member 3 is, for example, a member having a length of about 30 mm, a width of 3 mm, and a height of 7 mm, and the piezoelectric element member 2 is a member having a length of about 30 mm, a width of 1.5 mm, and a height of 1 mm. The piezoelectric elements 2 are joined 0.3 mm apart.

  Therefore, when the piezoelectric element member 2 on the base member 3 is bonded and fixed, the UV anaerobic adhesive layer containing the conductive particles in the first region 41 and the UV anaerobic adhesion not containing the conductive particles in the second region 42. Since the agent is present, positional displacement can be suppressed by ultraviolet curing after joining the piezoelectric element member 2 and the base member 3, and the common electrode 23 b of the piezoelectric element member 2 and the base member 3 can be made conductive.

  Thus, the adhesive layer that joins the piezoelectric element member and the base member contains the conductive particles, the first region that conducts the common electrode and the base member, and the second region that does not contain the conductive particles. Therefore, the piezoelectric element and the base member can be electrically connected in the first region, and the piezoelectric element member and the base member can be easily joined in the second region while securing the bonding strength. be able to.

Next, a second embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 6 is a schematic front view of the piezoelectric actuator, FIG. 7 is a side view of FIG. 6, and FIG. 8 is a plan view of the same.
Here, the 2nd area | region 42 which consists of UV anaerobic adhesive which does not contain electroconductive particle is arrange | positioned around the 1st area | region 41 which consists of UV anaerobic adhesive containing electroconductive particle. Thus, since the second region 42 of the UV anaerobic adhesive surrounds the first region 41 of the UV anaerobic adhesive containing conductive particles, the outer periphery of the joint surface between the piezoelectric element member 2 and the base member 3 is covered. It can be UV cured.

Next, a third embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 9 is a schematic front view of the piezoelectric actuator, FIG. 10 is a side view of FIG. 9, and FIG. 11 is a plan view of the same.
Here, the first region 41 is interspersed in the second region 42, and the UV anaerobic adhesion that does not contain conductive particles around the first region 41 made of the UV anaerobic adhesive containing conductive particles. The 2nd area | region 42 which consists of an agent is arrange | positioned. Thus, since the second region 42 of the UV anaerobic adhesive not containing conductive particles surrounds the first region 41 of the UV anaerobic adhesive containing conductive particles, the piezoelectric element member 2 and the base member 3 can be UV-cured on the outer periphery of the joint surface.

Next, a fourth embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 12 is a schematic front view of the piezoelectric actuator, FIG. 13 is a side view of FIG. 12, and FIG. 14 is a plan view of the same.
Here, by arranging the first region 41 between the second regions 42 and 42 along the piezoelectric element column arrangement direction corresponding to one piezoelectric element member 2, the first region along the piezoelectric element column arrangement direction is arranged. The second regions 42 and 42 are arranged on both sides in the direction orthogonal to the arrangement direction of the piezoelectric element columns with respect to the one region 41. As described above, since the second region 42 of the UV anaerobic adhesive not containing conductive particles sandwiches the first region 41 of the UV anaerobic adhesive containing conductive particles, sufficient bonding strength is ensured. can do.

Next, a fifth embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 15 is a schematic front view of the piezoelectric actuator, FIG. 16 is a side view of FIG. 15, and FIG. 17 is a plan view of the same.
Here, corresponding to one piezoelectric element member 2, a first region 41 is provided along the piezoelectric element column arrangement direction, and second regions 42, 42 are provided at both ends in the arrangement direction. As described above, since the second region 42 of the UV anaerobic adhesive not containing conductive particles sandwiches the first region 41 of the UV anaerobic adhesive containing conductive particles, sufficient bonding strength is ensured. can do.

Next, a sixth embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 18 is a schematic front view of the piezoelectric actuator, FIG. 19 is a side view of FIG. 18, and FIG. 20 is a plan view of the same.
Here, a plurality (six in this example) of piezoelectric element members 2 are arranged side by side on one base member 3 in a row. For example, the length of the base member 3 is about 300 mm, the length of the piezoelectric element member 2 is about 50 mm, and the gap between the piezoelectric element members 2 and 2 connected on a straight line is about 10 μm. Thereby, a long piezoelectric actuator can be obtained.

Next, a UV anaerobic adhesive containing conductive particles forming the first region in each of these embodiments will be described with reference to FIGS. 21 and 22. 21 and 22 are enlarged schematic explanatory views of a portion B in FIG.
In the first region 41, silver (Ag) is used as the conductive particles 41b, and 80% by weight of silver is added to the UV anaerobic adhesive 41a. In this case, spherical silver particles 41b1 may be added as shown in FIG. 21, or spherical silver particles 41b1 and flaky silver particles 42b2 may be mixed and added as shown in FIG. it can.

  By using silver for the conductive particles, the resistance between the piezoelectric element member and the base member can be reduced. Moreover, since spherical silver and flaky silver are mixed and used as the conductive particles, the contact area of the silver is increased, and the joint (connection portion) can be made to have a lower resistance without impairing the stirring property. it can.

  Next, an embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 23 is an explanatory perspective view of the appearance of the liquid discharge head. FIG. 24 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber along the line AA in FIG. 23 (direction perpendicular to the direction in which the liquid chambers are arranged). FIG. 5 is an explanatory cross-sectional view along the liquid chamber short direction (direction in which the liquid chambers are arranged).

  The liquid discharge head includes a flow path substrate (liquid chamber substrate) 101 formed of a SUS substrate, a vibration plate member 102 bonded to the lower surface of the flow path substrate 1, and a nozzle plate 103 bonded to the upper surface of the flow path substrate 101. And a liquid chamber (hereinafter referred to as a “pressurized liquid chamber” as a separate flow path) through which a nozzle 104 that discharges droplets (liquid droplets) communicates with each other. 106, a fluid resistance unit 107 that also serves as a supply path for supplying ink (recording liquid) as a liquid to the pressurized liquid chamber 106, and a common liquid chamber for supplying ink to the plurality of pressurized liquid chambers 106. 108 is formed. The recording liquid is supplied to the common liquid chamber 108 from an ink tank (not shown) via a supply path.

  Here, the flow path substrate 101 is formed by bonding a restrictor plate 101A and a chamber plate 101B. The flow path substrate 101 is formed by etching the SUS substrate using an acidic etchant or machining such as punching (pressing), so that each pressurized liquid chamber 6, fluid resistance portion 7, common liquid chamber 8, etc. Each opening is formed. The fluid resistance portion 107 is formed by opening a portion of the restrictor plate 101A and not opening a portion of the chamber plate 101B.

  The diaphragm member 102 is bonded and bonded to the chamber plate 101 </ b> B constituting the flow path substrate 101. The diaphragm member 2 is, for example, a resin layer (resin member) obtained by directly applying (coating) a resin whose linear expansion coefficient is larger than that of the metal member 21 to a metal member 121 such as a SUS substrate, and heating and solidifying the resin. The resin layer 122 forms a deformable portion (vibrating plate region) 102A which becomes the wall surface of the liquid chamber 106, and the vibrating plate region 102A is opposite to the liquid chamber 106. Is formed with an island-shaped protrusion (hereinafter also referred to as “island-shaped protrusion”) 102 </ b> B made of a metal member 121. In addition, a thick portion 102D made of a metal member 121 is formed (remaining) on the vibration plate member 102 at a position corresponding to the liquid chamber interval wall portion 106A of the flow path substrate 101. In addition, the diaphragm member 102 may be formed by bonding a resin layer and a metal member with an adhesive, or formed by electroforming such as Ni.

  The nozzle plate 103 forms a large number of nozzles 104 having a diameter of 10 to 30 μm corresponding to the pressurized liquid chambers 106 and is adhesively bonded to the restrictor plate 101 </ b> A of the flow path substrate 101. The nozzle plate 103 may be made of a metal such as stainless steel or nickel, a resin such as a polyimide resin film, silicon, or a combination thereof. Further, a water repellent film is formed on the nozzle surface (surface in the ejection direction: ejection surface) by a known method such as a plating film or a water repellent coating in order to ensure water repellency with ink.

  The piezoelectric actuator 110 according to the present invention is arranged on the outer surface of the diaphragm member 102 (on the side opposite to the pressurized liquid chamber 106). In the piezoelectric actuator 110, as in the piezoelectric actuator 1 according to the sixth embodiment described above, a plurality of piezoelectric element members 112 are arranged in a row on a single base member 113 having conductivity made of a metal material. The power supply member 115 is formed of an FPC or the like that is joined via an adhesive layer 4 having a region and a second region and supplies power to each piezoelectric element member 112.

  The piezoelectric element members 112 are formed adjacent to each other by forming slits (grooves) without being divided into an even number of piezoelectric element columns 112A and 112B through the slit grooves 115 at a predetermined pitch. The interval between the two piezoelectric element members 112 is also arranged as the groove width of the slit groove 115. Each piezoelectric element column of the piezoelectric element member 112 is used as a piezoelectric element column (driving piezoelectric element column) 112A that is driven every other one and a piezoelectric element column (non-driving piezoelectric element column) 112B that is not driven.

  The driving piezoelectric element column 112A of the piezoelectric actuator 110 is adhesively bonded to the island-shaped convex portion 102B of the diaphragm member 102, and the non-driving piezoelectric element column 112B is bonded to the thick portion 102D corresponding to the liquid chamber interval wall portion 106A. It is joined.

  The piezoelectric element member 112 is composed of a lead zirconate titanate (PZT) piezoelectric layer having a thickness of 10 to 50 μm / layer, and an internal electrode layer made of silver and palladium (AgPd) having a thickness of several μm / layer. In the same manner as the piezoelectric element member 2 described above, the internal electrodes are alternately electrically connected to the individual electrodes and common electrodes (not shown) that are the end face electrodes (external electrodes) of the end faces, respectively. The electrodes are formed up to the joint surface side with the base member 113.

  The diaphragm region 102A is displaced by the expansion and contraction of the driving piezoelectric element column 112A of the piezoelectric element member 112 whose piezoelectric constant is d33 (d33 indicates expansion / contraction perpendicular to the internal electrode surface (thickness direction)), and the liquid chamber 106 is displaced. It is designed to contract and expand. When the drive signal is applied to the piezoelectric element column 112A and charging is performed, the piezoelectric element column 112A expands. When the electric charge charged to the piezoelectric element column 112A is discharged, the piezoelectric element column 112A contracts in the opposite direction.

  It should be noted that a configuration in which the ink in the pressurized liquid chamber 106 is pressurized using a displacement in the d33 direction as the piezoelectric direction of the piezoelectric element member 112 (drive piezoelectric element column 112A) may be configured as the piezoelectric direction of the piezoelectric element member 112 in the d31 direction. The ink in the pressurizing liquid chamber 106 may be pressurized using the above displacement. In the present embodiment, a configuration using displacement in the d33 direction is adopted.

  Further, a frame member 117 is joined around the diaphragm member 102 with an adhesive. A buffer chamber 118 adjacent to the common liquid chamber 108 is formed in the frame member 117 via a diaphragm portion 102 </ b> C as a deformable portion constituted by the resin layer 122 of the diaphragm member 102. The diaphragm portion 102 </ b> C forms wall surfaces of the common liquid chamber 108 and the buffer chamber 118. Note that the buffer chamber 118 communicates with the atmosphere via the communication path 120.

  In this liquid discharge head, the piezoelectric element columns 112A and 112B of the piezoelectric element member 112 are formed at an interval of 300 dpi and are arranged in two rows facing each other. Further, the pressurized liquid chamber 106 and the nozzle 104 are arranged in a staggered manner with two rows arranged at intervals of 150 dpi, and a resolution of 300 dpi can be obtained in one scan.

  In the liquid ejection head configured in this way, for example, the drive piezoelectric element column 112A contracts by lowering the voltage applied to the drive piezoelectric element column 112A of the piezoelectric element member 112 from the reference potential, and the diaphragm region of the diaphragm member 102 102A descends and the volume of the pressurized liquid chamber 106 expands, so that ink flows into the pressurized liquid chamber 106, and then the voltage applied to the driving piezoelectric element column 112A is increased to stack the driving piezoelectric element columns 112A. The recording liquid in the pressurizing liquid chamber 106 is pressurized and is recorded from the nozzle 104 by contracting the volume / volume of the pressurizing liquid chamber 106 by extending in the direction and deforming the diaphragm region 102A in the direction of the nozzle 104. Liquid droplets are ejected (jetted).

  Then, by returning the voltage applied to the drive piezoelectric element column 112A to the reference potential, the diaphragm region 102A is restored to the initial position, and the pressurized liquid chamber 106 expands to generate a negative pressure. The recording liquid is filled into the pressurized liquid chamber 106 from the chamber 108. Therefore, after the vibration of the meniscus surface of the nozzle 104 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and striking or pushing can be performed depending on the direction of the drive waveform.

  As described above, since the liquid ejection head includes the piezoelectric actuator according to the present invention, a compact and long head can be obtained, and the common electrode line can be easily taken out.

Next, an example of the image forming apparatus according to the present invention including the liquid ejection apparatus according to the present invention will be described with reference to FIG. FIG. 26 is a schematic configuration diagram of the entire mechanism unit of the apparatus.
This image forming apparatus includes an image forming unit 202 and the like inside the apparatus main body 201, and includes a paper feed tray 204 on the lower side of the apparatus main body 201 on which a large number of recording media (sheets) 203 can be stacked. The paper 203 fed from the paper tray 204 is taken in, a required image is recorded by the image forming unit 202 while the paper 203 is transported by the transport mechanism 205, and then a paper discharge tray 206 mounted on the side of the apparatus main body 201. The sheet 203 is discharged.

  In addition, a duplex unit 207 that can be attached to and detached from the apparatus main body 201 is provided, and when performing duplex printing, the sheet 203 is taken into the duplex unit 207 while being transported in the reverse direction by the transport mechanism 205 after one-side (front) printing is completed. Then, the other side (back side) is sent to the transport mechanism 205 again as the printable side, and the sheet 203 is discharged to the discharge tray 206 after the other side (back side) printing is completed.

  Here, the image forming unit 202, for example, ejects liquid droplets of each color of black (K), cyan (C), magenta (M), and yellow (Y), and is a full line type of four liquids according to the present invention. The recording heads 211k, 211c, 211m, and 211y (which are referred to as “recording heads 211” when the colors are not distinguished) are configured by ejection heads, and each recording head 211 has a nozzle surface on which nozzles for ejecting droplets are formed downward. The head holder 213 is attached.

  In addition, maintenance and recovery mechanisms 212k, 212c, 212m, and 212y for maintaining and recovering the head performance corresponding to each recording head 211 (referred to as “maintenance and recovery mechanism 212” when colors are not distinguished) are provided. During the head performance maintenance operation such as wiping processing, the recording head 211 and the maintenance / recovery mechanism 212 are relatively moved so that the capping member constituting the maintenance / recovery mechanism 212 faces the nozzle surface of the recording head 211.

  Here, the recording head 211 is arranged to eject droplets of each color in the order of yellow, magenta, cyan, and black from the upstream side in the paper conveyance direction, but the arrangement and the number of colors are not limited to this. Further, as the line-type head, one or a plurality of heads provided with a plurality of nozzle rows for discharging droplets of each color at predetermined intervals can be used, and a recording liquid cartridge for supplying a recording liquid to the head and the head. Can be integrated or separated.

  The sheets 203 in the sheet feeding tray 204 are separated one by one by a sheet feeding roller (half-moon roller) 221 and a separation pad (not shown) and fed into the apparatus main body 201, and are registered along the guide surface 223 a of the conveyance guide member 223. 225 and the conveying belt 233, and are sent to the conveying belt 233 of the conveying mechanism 205 via the guide member 226 at a predetermined timing.

  In addition, a guide surface 223 b that guides the sheet 203 sent out from the duplex unit 207 is also formed on the transport guide member 223. Further, a guide member 227 for guiding the sheet 203 returned from the transport mechanism 205 during duplex printing to the duplex unit 207 is also provided.

  The transport mechanism 205 includes an endless transport belt 233 that is stretched between a transport roller 231 that is a driving roller and a driven roller 232, a charging roller 234 that charges the transport belt 233, and an image forming unit 202. A platen member 235 that maintains the flatness of the conveying belt 233 at the opposite portion, a pressing roller 236 that presses the paper 203 fed from the conveying belt 233 against the conveying roller 231, and other recording liquid that is not shown, but adheres to the conveying belt 233. It has a cleaning roller made of a porous material or the like, which is a cleaning means for removing (ink).

  A paper discharge roller 238 and a spur 239 for sending the paper 203 on which an image is recorded to the paper discharge tray 206 are provided on the downstream side of the transport mechanism 205.

  In the image forming apparatus configured as described above, the transport belt 233 rotates in the direction indicated by the arrow, and is positively charged by coming into contact with the charging roller 334 to which a high potential applied voltage is applied. In this case, the charging belt 233 is charged at a predetermined charging pitch by switching the polarity of the charging voltage of the charging roller 234 at a predetermined time interval.

  Here, when the sheet 203 is fed onto the conveying belt 233 charged to this high potential, the inside of the sheet 203 is in a polarized state, and the charge opposite in polarity to the charge on the conveying belt 233 is conveyed to the conveying belt 233 of the sheet 203. The charge on the transport belt 233 and the charge on the transported sheet 203 are electrostatically attracted to each other, and the sheet 203 is electrostatically attracted to the transport belt 233. Is done. In this way, the sheet 203 strongly adsorbed to the conveyor belt 233 is calibrated for warpage and unevenness, and a highly flat surface is formed.

  Then, the paper 203 is moved around the conveyor belt 233 and droplets are ejected from the recording head 211, whereby a required image is formed on the paper 203, and the paper 203 on which the image is recorded is discharged to the paper discharge roller 238. Is discharged to the discharge tray 206.

  As described above, since the image forming apparatus includes the recording head including the liquid discharge head according to the present invention, high-speed recording with a long head can be achieved.

  In the above embodiment, the line type image forming apparatus is described as the image forming apparatus according to the present invention, but the present invention can be similarly applied to a serial type image forming apparatus in which a recording head is mounted on a carriage.

It is typical front explanatory drawing which shows 1st Embodiment of the piezoelectric actuator which concerns on this invention. It is side surface explanatory drawing of FIG. It is an expansion side sectional explanatory view of a piezoelectric element member similarly. FIG. 2 is an enlarged explanatory view of a part A in FIG. 1. FIG. 2 is an explanatory plan view of FIG. 1. It is typical front explanatory drawing which shows 2nd Embodiment of the piezoelectric actuator which concerns on this invention. It is side surface explanatory drawing of FIG. It is a plane explanatory drawing similarly. It is typical front explanatory drawing which shows 3rd Embodiment of the piezoelectric actuator which concerns on this invention. It is side surface explanatory drawing of FIG. It is a plane explanatory drawing similarly. It is typical front explanatory drawing which shows 4th Embodiment of the piezoelectric actuator which concerns on this invention. It is side surface explanatory drawing of FIG. It is a plane explanatory drawing similarly. It is typical front explanatory drawing which shows 5th Embodiment of the piezoelectric actuator which concerns on this invention. It is side surface explanatory drawing of FIG. It is a plane explanatory drawing similarly. It is typical front explanatory drawing which shows 6th Embodiment of the piezoelectric actuator which concerns on this invention. It is side surface explanatory drawing of FIG. It is a plane explanatory drawing similarly. It is an expansion typical explanatory drawing of the B section of Drawing 1 used for explanation of an adhesive layer of the 2nd field containing conductive particles. It is an expansion typical explanatory view of the B section of Drawing 1 used for explanation of other examples of the adhesive layer of the 2nd field similarly containing conductive particles. FIG. 2 is an external perspective view illustrating an example of a liquid discharge head according to the present invention. FIG. 24 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber (a direction orthogonal to the direction in which the liquid chambers are arranged) along the line AA in FIG. FIG. 5 is a cross-sectional explanatory view along the liquid chamber short direction (liquid chamber arrangement direction). 1 is an overall configuration explanatory view showing an example of an image forming apparatus according to the present invention including a liquid ejection apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator 2 ... Piezoelectric element member 3 ... Base member 4 ... Adhesive layer 12 ... Piezoelectric element pillar 23b ... Common electrode 41 ... 1st area | region 41a ... UV anaerobic adhesive 41b ... Conductive particle (silver)
42 ... second region 101 ... channel substrate 102 ... vibrating plate member 103 ... nozzle plate 104 ... nozzle 106 ... pressurized liquid chamber 110 ... piezoelectric actuators 211k, 211c, 211m, 211y ... recording head (liquid ejection head)

Claims (9)

A piezoelectric element member formed by arranging a plurality of piezoelectric element columns is bonded to a conductive base member via an adhesive layer,
A common electrode common to the plurality of piezoelectric element columns is provided on a joint surface of the piezoelectric element member with the base member,
The adhesive layer on the bonding surface includes conductive particles, and includes a first region that conducts the common electrode and the base member, and a second region that does not include the conductive particles. Piezoelectric actuator.   2. The piezoelectric actuator according to claim 1, wherein the first region is surrounded by the second region. 3.   2. The piezoelectric actuator according to claim 1, wherein both ends of the first region in a direction orthogonal to the arrangement direction of the piezoelectric element columns are sandwiched between the second regions.   2. The piezoelectric actuator according to claim 1, wherein both ends of the first region in the arrangement direction of the piezoelectric element columns are sandwiched between the second regions.   5. The piezoelectric actuator according to claim 1, wherein a plurality of the piezoelectric element members are joined to one base member. 6.   6. The piezoelectric actuator according to claim 1, wherein the conductive particles are silver.   The piezoelectric actuator according to claim 6, wherein the conductive particles are a mixture of spherical and flaky particles. A flow path member that forms a plurality of liquid chambers each communicating with a plurality of nozzles that discharge droplets;
A diaphragm member forming at least one wall surface of the liquid chamber;
A piezoelectric actuator for deforming the diaphragm member,
The liquid ejecting head according to claim 1, wherein the piezoelectric actuator is the piezoelectric actuator according to claim 1.   An image forming apparatus comprising the liquid discharge head according to claim 8.

Images