JP2008068555A - Liquid discharge head and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid discharge head which discharges three or more kinds of liquid from one reliable head and an image formation device equipped with this head. <P>SOLUTION: Piezoelectric element members 42A to 42D consisting of integral forms of three or more piezoelectric elements are arranged by junction and formed in one piece in one base member 41. The base member 41 is provided with a through hole 44 between the piezoelectric elements 42B and 42C. FPC cables 43B, 43C which are directly joined to the piezoelectric element 42B, 42C, respectively are pulled out to the side opposite to the piezoelectric element junction side of the base member 41 through the through hole 44. <P>COPYRIGHT: (C)2008,JPO&INPIT

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, and a multifunction machine of these, for example, a liquid ejection apparatus including a recording head composed of a liquid ejection head (droplet ejection head) that ejects liquid droplets of a recording liquid (liquid) As a liquid while transporting a medium (hereinafter also referred to as “paper”, but the material is not limited, and a recording medium, a recording medium, a transfer material, recording paper, etc. are also used synonymously). The recording liquid (hereinafter also referred to as ink) is attached to a sheet to form an image (recording, printing, printing, and printing are also used synonymously).

  The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The term “not only” 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. Further, the liquid is not limited to the recording liquid and ink, and is not particularly limited as long as it is a liquid capable of forming an image. Further, the liquid ejection apparatus means an apparatus that ejects liquid from a liquid ejection head, and is not limited to an apparatus that forms an image.

  A liquid discharge head (droplet discharge head) used in such an image forming apparatus includes a nozzle that discharges droplets, a liquid chamber that communicates with the nozzle, a vibration plate that forms a wall surface of the liquid chamber, and a vibration plate There is a piezoelectric head provided with a piezoelectric element that pressurizes the liquid in the liquid chamber via the. Regarding the piezoelectric head, the following is known.

In Patent Document 1, a laminated piezoelectric element corresponding to a pressurized liquid chamber that communicates with a nozzle that discharges droplets is disposed on a base substrate, and a liquid that discharges droplets from the nozzles by driving the piezoelectric element. In the droplet discharge head, a piezoelectric element having a substantially L-shaped cross-section is bonded onto a base substrate having a comb-like cross-sectional shape, and the comb-teeth portion of the base substrate is inserted into a printed board having a through-hole. A droplet discharge head in which a substrate and a piezoelectric element are electrically connected via connection means is described.
JP 2004-082650 A

In Patent Document 2, in a head that is ejected by piezoelectric elements arranged on a base member corresponding to the arrangement of liquid chambers, the base member is a member made of metal, and an anaerobic adhesive that starts polymerization by metal ions. An ink jet head in which a base member and a piezoelectric element are joined is described.
Japanese Patent Laid-Open No. 2003-21658

Patent Document 3 describes an electrostatic ink jet head in which a plurality of nozzles are integrally arranged on a plane, and the arrangement is a matrix in which three or more nozzle rows arranged in accordance with a certain rule are arranged in parallel.
JP 2002-254635 A

In Patent Document 4, an alignment through-hole is provided for positioning the nozzle plate with respect to the electrostatic actuator, and the substrate electrode for driving the diaphragm and the positioning operation are performed on the electrode substrate of the electrostatic actuator. An alignment head is provided and an inkjet head is described.
JP 2002-210987 A

In Patent Document 5, the cover plate is formed with a protruding portion that protrudes from the surface in contact with the base plate, and each drive electrode is pulled out on the protruding portion and connected to a drive circuit disposed on the protruding portion. In addition, there is described an ink jet head in which a base plate and a cover plate are aligned and alternately stacked in a direction orthogonal to an arrangement direction of ink chambers, and a plurality of actuator units are integrally assembled.
Japanese Patent Laid-Open No. 10-146974

In Patent Document 6, piezoelectric vibrators that vibrate in the d33 mode are fixed to a fixed substrate in a row, and the flow path units are arranged at the same pitch as the arrangement pitch of the pressure generating chambers of the flow path units on both sides of the rows of piezoelectric vibrators. Inkjet recording heads are described in which dummy vibrators for supporting the substrate are fixed to a fixed substrate in rows.
Japanese Patent No. 3578190

In Patent Document 7, among the plurality of plates constituting the flow path unit, the outermost layer plate including one surface of the flow path unit to which the actuator unit that changes the volume of each pressure chamber is fixed is stacked on the outermost layer. Part of the region where the actuator unit of the outermost layer plate is not fixed on one surface is bent toward the actuator unit side, and the flow path passes through a part of the bent outermost layer plate. An ink jet head is described in which a unit and a common electrode are electrically connected.
JP 2006-035571 A

Patent Document 8 includes an ink jet recording head including a plurality of ink passages and a plurality of actuators for ejecting ink in the ink passages, and a carriage on which the recording head is mounted. In addition to providing the connected terminals, the printed circuit board is provided with a wiring pattern having a connection terminal corresponding to the terminal for supplying power to the actuator, and the recording head is mounted on the printed circuit board in correspondence with the connection terminal of the wiring pattern. Inkjet recording apparatus is described.
JP-A-10-278283

Patent Document 9 discloses a frame member in which at least one common liquid chamber and an actuator storage space are formed, an actuator unit having a plurality of actuators that are arranged in the actuator storage space and can be independently driven, and each actuator. The individual liquid chamber having a diaphragm driven by the frame member as a boundary member with the frame member and individually communicating with the common liquid chamber via a supply port formed in the diaphragm has a plurality of discharge holes therein. A liquid chamber provided individually corresponding to the actuator, in which a bubble discharge passage is formed with an opening end on one side in the region in contact with the opening end edge on the diaphragm side of the inner wall of the common liquid chamber and the other side opening to the outside An inkjet head comprising a unit is described.
JP 2003-072065 A

  By the way, in the piezoelectric type liquid ejection head, when there are a plurality of types of liquid ejected from one head, at least the same number of nozzle rows as the type of liquid (nozzles arranged in a row) are required. As for the piezoelectric elements for pressurizing the liquid in the room, it is necessary to arrange the same number of rows of the plurality of piezoelectric elements as the nozzle rows.

  These piezoelectric elements are usually joined to one base member as a set of two at most, for reasons such as winding of an FPC cable for applying a driving voltage, thereby forming an actuator unit. Therefore, when there are three or more types of liquid to be discharged, a plurality of actuator units are required.

  As a result, in joining the actuator unit and the flow path unit, it is necessary to handle each actuator unit and move it to the vicinity of the desired position, and then align and join them, and the joining operation is repeated several times. Time increases and productivity decreases.

  Therefore, as described in Patent Document 1, there is a liquid discharge head in which a plurality of rows of piezoelectric elements are arranged on one base member. However, in order to drive the piezoelectric elements, a signal transmission cable (for example, FPC) for supplying a driving signal must be connected. When a plurality of piezoelectric element rows are arranged on one base member, the piezoelectric element rows are arranged between the rows. It becomes impossible to pull out the cable located in without being bent. However, bending a cable directly bonded to a piezoelectric element has a problem that a load is applied to the bonded portion between the piezoelectric element and the cable, which causes a decrease in connection reliability, a collapse of the piezoelectric element, and the like.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejection head that ejects three or more types of liquids from a highly reliable head and an image forming apparatus including the liquid ejection head.

  In order to solve the above problems, in the liquid discharge head according to the present invention, a plurality of nozzles for discharging droplets and a plurality of liquid chambers communicating with the nozzles are arranged side by side, and each liquid chamber in each row is arranged. A plurality of piezoelectric elements that generate pressure to pressurize the liquid in the liquid chamber are arranged side by side, and the plurality of piezoelectric elements are joined to the same base member, and the base member is interposed between the rows of piezoelectric elements. A through-hole is formed, and a signal transmission cable that transmits a drive signal and is directly joined to the piezoelectric element through the through-hole is drawn out.

  Here, the base member has a configuration in which the cross-sectional shape along the direction orthogonal to the direction in which the piezoelectric elements are arranged is formed in an uneven shape, and the piezoelectric element is arranged on the uppermost surface of the convex portion, the base member is a metal member, The piezoelectric element is bonded to the base member with an ultraviolet curable anaerobic adhesive, and the corner of at least one of the bonding surfaces of the piezoelectric element and the base member is chamfered or formed in an R shape. And can.

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

  According to the liquid ejection head of the present invention, the base member in which a plurality of piezoelectric elements are arranged in three or more rows has through holes formed between the rows of piezoelectric elements, and is directly bonded to the piezoelectric elements through the through holes. Because the signal transmission cable that transmits the drive signal is drawn out, the signal transmission cable arranged between the rows of piezoelectric elements can be pulled out without bending through the through hole, and the reliability Will improve.

  According to the image forming apparatus of the present invention, since the liquid discharge head according to the present invention is provided, the reliability is improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 1 is a schematic exploded perspective view of the head, FIG. 2 is a cross-sectional view of the head along the longitudinal direction of the liquid chamber, FIG. 3 is a perspective view of the actuator unit, and FIG. 4 is a cross-sectional view of the actuator unit. It is.

The liquid discharge head includes a nozzle plate 1, a flow path member 2, a vibration plate member 3, an actuator unit 4, and a frame member 5, and includes the nozzle plate 1, the flow path member 2, and the vibration plate member 3. A liquid chamber (flow path) unit 6 is configured.
ing.

  A plurality of nozzles 11 for discharging droplets are formed on the nozzle plate 1 at a pitch of 150 dpi, for example. Four rows of nozzles 11 (referred to as “nozzle rows”) are arranged in four rows. Although not shown, a fluorine-based water repellent film is formed on the surface of the nozzle plate 1 on the droplet discharge side. The nozzle plate 1 is formed of a resin member, a metal member such as nickel, or a laminated member of a resin member and a metal member. In addition, the nozzle plate 1 can also be set as the structure which arrange | positioned the several sheets side by side instead of making one sheet.

  The flow path member 2 is formed with a pressurized liquid chamber 22 through which the nozzle 11 communicates via the communication path 21. The liquid chambers 22 (including the communication path 21) correspond to each nozzle 11 and are arranged in four rows corresponding to each nozzle row. The flow path member 2 is formed of, for example, a SUS laminated member by etching a silicon substrate, etching a metal member such as SUS, or punching.

  A diaphragm-like diaphragm (diaphragm portion) 31 corresponding to each liquid chamber 22 and forming one surface of each liquid chamber 22 is formed on the diaphragm member 3, and a convex portion 32 is formed on the diaphragm 31. Has been. The diaphragm member 3 is formed of, for example, a multi-layer Ni electroformed member or a laminated member of a resin member and a metal member.

  The actuator unit 4 includes four laminated piezoelectric element members 42A to 42D (hereinafter referred to as “piezoelectric element members” when not distinguished from each other) in which a plurality of piezoelectric elements 42a corresponding to the respective liquid chambers 22 are formed on one base member 41. 42).), Four rows of piezoelectric elements 42a are arranged, and a signal transmission cable for transmitting a drive signal to the piezoelectric elements 42a to the end face electrodes of the piezoelectric elements 42a of each piezoelectric element member 42 is provided. FPC cables 43A to 43D (hereinafter referred to as “FPC cable 43” when not distinguished) are soldered.

  Here, the piezoelectric element member 42 is formed by alternately stacking piezoelectric layers and internal electrodes and subjecting the internal electrodes to alternate end faces to be connected to the end face electrodes by half-cut dicing. Thus, the plurality of piezoelectric elements 42a are integrally divided.

  In addition, since the end electrode on both end faces of the piezoelectric element member 42 is routed to the same end face as the end face electrode on the individual electrode side through an internal electrode that is not cut, one end face of the piezoelectric element member 42 is provided. The FPC cable 43 can be soldered to the side. The piezoelectric element member 42 is also formed with an alignment slit 42b during dicing. In addition, here, a piezoelectric element member in which a plurality of piezoelectric elements 42a are integrated by half-cut dicing is used, but a configuration in which the piezoelectric elements are completely divided into individual piezoelectric elements may be employed.

  The side of the base member 41 where the piezoelectric element members 42 are joined is formed such that the cross-sectional shape in the direction orthogonal to the direction in which the piezoelectric elements 42a are arranged (the direction along the rows of piezoelectric elements) is uneven, A piezoelectric element 42a (piezoelectric element member 42) is bonded to the uppermost surface of 41a. Here, there are four rows of the piezoelectric elements 42a, and two rows can be arranged on each convex portion. Therefore, the cross-sectional shape of the base member 41 is a concave shape. In the case where the number of rows of piezoelectric elements is six, for example, as shown in FIG. 7, the cross-sectional shape may be formed in a concavo-convex shape (a shape in which two concave portions are overlapped). .

  Further, the base member 41 is formed with a through hole 44 between the piezoelectric element members 42B and 42C, and is connected to the FPC cable 43B and the piezoelectric element member 42C connected to the piezoelectric element member 42B not located at the end of the base member 41. The FPC cable 43 </ b> C is led out to the back side of the base member 41 (the side opposite to the side where the piezoelectric element member 42 is joined) through the through hole 44. Thus, by pulling out the FPC cables 43B and 43C through the through hole 44, it is not necessary to bend the FPC cables 43B and 43C in a complicated manner, and the joining portions of the FPC cables 43B and 43C that are directly joined to the piezoelectric element 42a. The load on is no longer applied. The FPC cable 43A connected to the piezoelectric element member 42A located at the end of the base member 41 and the FPC cable 43D connected to the piezoelectric element member 42D are pulled out along the side surface of the base member 41 as they are.

  The base member 41 can be made of, for example, resin, but is preferably a metal material. By adopting a highly rigid metal material, it is possible to suppress the vibration of the piezoelectric element 42a from being transmitted to the main body. In addition, by forming the base member 41 with a metal material, the selection range of the processing method of the base member 41 is widened. For example, by adopting metal injection or drawing processing, the material and processing cost of the base member can be reduced. It becomes like this.

  The frame member 5 forms common liquid chambers 51 </ b> A, 51 </ b> B, 51 </ b> C, and 51 </ b> D that supply the recording liquid to the liquid chambers 22 through the supply ports 33 of the diaphragm member 3. The common liquid chambers 51A, 51B, 51C, and 52D are supplied with a recording liquid from the outside through a supply path (not shown). The frame member 5 is formed with storage portions 52A and 52B for storing the base member 41, and the central portion 53 that forms the common liquid chambers 51B and 51C between the storage portions 52A and 52B penetrates the base member 41. It penetrates the hole 44. The frame member 5 is formed of, for example, a resin member. The frame member 5 can be divided into a plurality of members.

  In the liquid ejection head configured as described above, for example, by lowering the voltage applied to the piezoelectric element 42a from the reference potential, the piezoelectric element 42a contracts, and the diaphragm 31 descends to expand the volume of the liquid chamber 22. Then, the ink flows into the liquid chamber 22, and then the voltage applied to the piezoelectric element 42 a is increased to extend the piezoelectric element 42 a, and the diaphragm 31 is deformed in the direction of the nozzle 11 to contract the volume / volume of the liquid chamber 22. As a result, the ink in the liquid chamber 22 is pressurized, and ink droplets are ejected (ejected) from the nozzle 11.

  Then, by returning the voltage applied to the piezoelectric element 42a to the reference potential, the diaphragm 31 is restored to the initial position, and the liquid chamber 22 expands to generate a negative pressure. 22 is filled with ink. Therefore, after the vibration of the meniscus surface of the nozzle 11 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.

  In this liquid ejection head, as described above, a base member in which a plurality of piezoelectric elements are arranged in three or more rows has through holes formed between the rows of piezoelectric elements, and the piezoelectric elements are directly passed through the through holes. Since the joined signal transmission cable for transmitting the drive signal is drawn out, the signal transmission cable arranged between the rows of piezoelectric elements can be pulled out through the through hole without being bent. The bending stress does not act on the joint between the cable and the cable, and the reliability is improved.

Here, the bonding arrangement of the piezoelectric element member 42 to the base member 41 will be described with reference to FIGS.
The piezoelectric element member 42 is bonded to the upper surface of the convex portion 41a of the base member 41 with an ultraviolet curable anaerobic adhesive. By using an ultraviolet curable anaerobic adhesive, it is possible to immediately cure by ultraviolet irradiation to ensure sufficient bonding strength. Moreover, when the base member 41 is a metal member, sufficient adhesive force can be obtained with an anaerobic adhesive.

  In this case, a chamfered portion 41 c is provided at a corner portion of the joint surface of the convex portion 41 a of the base member 41 to which the piezoelectric element member 42 is joined. As a result, as described above, when the piezoelectric element member 42 is bonded and bonded to the base member 41 using the ultraviolet curable anaerobic adhesive, as shown in FIG. 6, it protrudes from the chamfered portion 41c of the base member 41 described above. The adhesives 71a to 71d can be irradiated with ultraviolet rays, and the adhesive strength can be secured immediately. Moreover, since it can irradiate from diagonally, the occupation space of an ultraviolet fiber can be reduced and the space saving of an apparatus is attained. Here, an example in which a corner portion of the joint surface of the convex portion 41a of the base member 41 is chamfered is described, but the corner portion of the joint surface of the convex portion 41a of the base member 41 is formed in an R shape. Even if it is the structure which has, the same effect is obtained. Further, the same effect can be obtained by making the piezoelectric element member 42 side chamfered or rounded.

  In addition, since the through hole 44 is formed in the base member 41, it is difficult to irradiate ultraviolet rays from obliquely above the adhesives 71b and 71c that protrude from the chamfered portion 41c facing the convex portion 42a due to limitations of the joining device and the like. In some cases, ultraviolet rays can be irradiated through the through hole 44.

  Next, the manufacturing process of the liquid discharge head will be described. The frame member 5 is joined to the flow path unit 6 in advance, and the actuator unit 4 is lifted from below to align the alignment groove 42b of the piezoelectric element member 42 and the flow path unit. The alignment holes 6a (see FIG. 1) formed at two locations along the longitudinal direction of the image 6 are aligned by image processing. Thereafter, the adhesive is discharged and supplied to the frame member 5 and the end surface of the base member 41 by a dispenser or the like, and joined.

  Since a plurality of rows of piezoelectric elements are joined to one base member 41, the handling, alignment and joining processes of the actuator unit and the flow path unit can be done only once, improving productivity and operating the joining device. The total cost reduction can be reduced by improving the rate.

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. 8 is a schematic configuration diagram showing a mechanism part of the apparatus, and FIG. 9 is a plan view of a main part of the apparatus.
The carriage 113 is slidably held in the main scanning direction by the main guide rod 111 and the secondary guide rod 112 horizontally mounted on the left and right main side plates 101A and 101B, and the direction indicated by the arrow through the timing belt by a main scanning motor (not shown). Move and scan in the carriage main scanning direction.

  The carriage 113 has a plurality of nozzle rows that eject droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K), and a recording head that includes the liquid ejection head according to the present invention. A plurality of nozzles (ejection ports) 114 are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward. As shown in FIG. 1 described above, the recording head 114 has a plurality of nozzles 11 that eject droplets of yellow (Y), cyan (C), magenta (M), and black (K) on the nozzle plate 1. The nozzle row of each color arranged is provided.

  The carriage 113 is also equipped with a head tank 115 for each color for supplying ink of each color to the recording head 114. Each color head tank 115 is replenished and supplied with each color ink from each color ink cartridge 120 mounted on the cartridge loading section 117 via a flexible supply tube 116 for each color. The cartridge loading section 117 is provided with a supply pump unit 118 that is a liquid feeding means for feeding ink in the ink cartridge 120. The supply tube 116 is held on the front stay 121 by a holding member 122 in the middle.

  On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feeding tray 140, a half-moon roller (feeding) that separates and feeds the paper 142 one by one from the paper stacking unit 141. A separation pad 144 made of a material having a large friction coefficient is provided facing the paper roller 143 and the paper feed roller 143, and the separation pad 144 is urged toward the paper feed roller 143 side.

  A guide member 145 for guiding the paper 142, a counter roller 146, a transport guide member 147, and a tip pressure roller for feeding the paper 142 fed from the paper feeding unit to the lower side of the recording head 114. And a holding belt 148 that is a conveying means for electrostatically attracting the fed paper 142 and conveying it at a position facing the recording head 114.

  The conveyor belt 151 is an endless belt, and is configured to wrap around the conveyor roller 152 and the tension roller 153 and circulate in the belt conveyance direction (sub-scanning direction). Further, a charging roller 156 that is a charging unit for charging the surface of the transport belt 151 is provided. The charging roller 156 is disposed so as to come into contact with the surface layer of the conveyor belt 151 and to rotate following the rotation of the conveyor belt 151. Further, a guide member 157 serving as a platen portion is disposed on the back side of the conveyance belt 151 corresponding to the printing area by the recording head 114. The transport belt 151 rotates in the belt transport direction when the transport roller 152 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 142 recorded by the recording head 114, a separation claw 161 for separating the paper 142 from the conveying belt 151, a paper discharge roller 162, and a paper discharge roller (spur roller). 163, and a paper discharge tray 163 below the paper discharge roller 162.

  A double-sided unit 171 is detachably attached to the back surface of the apparatus main body. The duplex unit 171 takes in the paper 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds it again between the counter roller 146 and the transport belt 151. The upper surface of the duplex unit 171 is a manual feed tray 172.

  Further, a maintenance / recovery mechanism 181 including a recovery means for maintaining and recovering the nozzle state of the recording head 114 is disposed in a non-printing area on one side in the scanning direction of the carriage 113. The maintenance / recovery mechanism 181 includes a cap member 182 for collectively capping the nozzles 11 of the recording head 114, a wiper blade 183 that is a blade member for wiping the nozzle surface, and a thickened recording liquid. An empty discharge receptacle 84 for receiving droplets when performing empty discharge for discharging droplets that do not contribute to recording in order to be discharged is provided.

  Then, the waste liquid of the recording liquid generated by the maintenance / recovery operation by the maintenance / recovery mechanism 181, the ink discharged to the cap 182, the ink attached to the wiper blade 183 and removed by the wiper cleaner 185, and the idle ejection to the idle ejection receptacle 194 The discharged ink is discharged and stored in a waste liquid tank (not shown).

  In addition, in the non-printing area on the other side of the carriage 113 in the scanning direction, there is an empty space for receiving liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. A discharge receiver 188 is disposed, and the idle discharge receiver 188 includes an opening 189 along the nozzle row direction of the recording head 114.

  In the ink jet recording apparatus configured as described above, the paper 142 is separated and fed one by one from the paper feed tray 140, and the paper 142 fed substantially vertically upward is guided by the guide 145, and the conveyance belt 151 and the counter roller 146, and the leading end is guided by the conveying guide 147 and pressed against the conveying belt 151 by the leading end pressing roller 149, and the conveying direction is changed by approximately 90 °.

  At this time, a charging voltage pattern in which a positive output and a negative output are alternately repeated from the AC bias supply unit of the control unit (not shown) to the charging roller 156, that is, an alternating voltage is applied and the conveying belt 151 is alternating, That is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction which is the circumferential direction. When the sheet 142 is fed onto the conveying belt 151 that is alternately charged with plus and minus, the sheet 142 is attracted to the conveying belt 151, and the sheet 142 is conveyed in the sub-scanning direction by the circumferential movement of the conveying belt 151.

  Therefore, by driving the recording head 114 according to the image signal while moving the carriage 113, ink droplets are ejected onto the stopped sheet 142 to record one line, and after the sheet 142 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 142 reaches the recording area, the recording operation is finished, and the paper 142 is discharged onto the paper discharge tray 163.

  During printing (recording) standby, the carriage 113 is moved to the maintenance / recovery mechanism 181 side, and the ejection surface (nozzle surface) of the recording head 114 is capped by the cap member 182 to keep the nozzle in a wet state. Prevents ejection failure due to recording liquid drying. Further, the recording liquid is sucked from the nozzle by a suction pump (not shown) with the cap member 182 capping the ejection surface of the recording head 114 (referred to as “nozzle suction” or “head suction”) to increase the viscosity. Perform recovery operation to discharge liquid and bubbles. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. Thereby, the stable ejection performance of the recording head 114 is maintained.

  As described above, since the image forming apparatus includes the recording head 114 including the liquid ejection head according to the present invention with high reliability, the reliability is improved.

  In each of the above embodiments, the printer configuration has been described as the image forming apparatus according to the present invention. However, the present invention is not limited to this, and can be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. Further, the present invention can also be applied to an image forming apparatus using a recording liquid other than ink, a fixing processing liquid, a DNA sample, a resist or the like, and other apparatuses for ejecting liquid droplets.

FIG. 3 is a schematic exploded perspective view illustrating an example of an embodiment of a liquid discharge head according to the present invention. It is sectional explanatory drawing along the liquid chamber longitudinal direction of the head. It is a perspective explanatory view of the actuator unit of the head. It is a cross-sectional explanatory view of the actuator unit. It is a perspective explanatory view of the base member of the head. It is explanatory drawing with which it uses for description of joining of the base member and piezoelectric element member of the head. It is an isometric view explanatory drawing used for description of the other example of a base member. FIG. 2 is a configuration diagram showing an outline of a mechanism portion of an image forming apparatus according to the present invention including a liquid ejection head according to the present invention. It is principal part plane explanatory drawing of the mechanism part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Nozzle plate 2 ... Channel member (channel plate)
DESCRIPTION OF SYMBOLS 3 ... Vibration plate member 4 ... Actuator unit 5 ... Frame member 11 ... Nozzle 22 ... Liquid chamber 31 ... Vibration plate 41 ... Base member 42A, 42B, 42C, 42D ... Piezoelectric element member 42a ... Piezoelectric element 43 ... FPC cable 44 ... Penetration Hole 113 ... carriage 114 ... recording head (liquid ejection head)

Claims (6)

A plurality of nozzles that discharge droplets and a plurality of liquid chambers that communicate with each nozzle are arranged in at least three rows,
A plurality of piezoelectric elements that generate pressure to pressurize the liquid in the liquid chamber corresponding to each liquid chamber in each row are arranged side by side,
The plurality of piezoelectric elements are bonded to the same base member,
In this base member, a through hole is formed between the rows of the piezoelectric elements,
A liquid ejection head, wherein a signal transmission cable for transmitting a drive signal, which is directly bonded to the piezoelectric element through the through hole, is drawn out.   2. The liquid ejection head according to claim 1, wherein the base member is formed to have a concave-convex shape in a cross-section along a direction orthogonal to the arrangement direction of the piezoelectric elements, and the piezoelectric element is disposed on an uppermost surface of the convex portion. A liquid discharge head.   The liquid discharge head according to claim 1, wherein the base member is a metal member.   4. The liquid discharge head according to claim 1, wherein the piezoelectric element is joined to the base member with an ultraviolet curable anaerobic adhesive.   5. The liquid discharge head according to claim 4, wherein a corner portion of at least one joint surface of the piezoelectric element and the base member is chamfered or formed in an R shape. .   6. An image forming apparatus for forming an image by discharging liquid droplets from a liquid discharge head, comprising the liquid discharge head of the head according to claim 1.

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