JP5365553B2 - Liquid ejection head and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: it is necessary to miniaturize a piezoelectric actuator in accordance with achievement of high density and high integration, and also, it is necessary to enhance bonding accuracy with a diaphragm member. <P>SOLUTION: Two piezoelectric members 12 and 12 are bonded and fixed side by side on a base member 13, and at both ends of each of the piezoelectric members 12, level difference formation parts 103A and 103B are disposed on the side of the surface bonded with the diaphragm member 3, and an alignment groove part 106 is disposed in an opposing surface 104 opposing the diaphragm member 3, of the level difference formation part 103A disposed at one end, and an opposing surface 107 opposing the diaphragm member 3, of the level difference formation part 103B disposed at the other end functions as an adhesive applying area for applying a temporary tacking adhesive 108. Between the adjacent piezoelectric members 12 and 12, the alignment groove parts 106 and the adhesive applying areas are arranged with a reverse relationship, and also, the alignment groove part 106 and the adhesive applying area disposed on the same end side are arranged in an overlapped state in a short-side direction of the piezoelectric members 12, 12. <P>COPYRIGHT: (C)2011,JPO&amp;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, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. An apparatus (ink jet recording apparatus) is known. This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

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

  As a liquid discharge head, for example, a groove is formed on a piezoelectric body as pressure generating means for generating pressure by applying ink, which is liquid in a liquid chamber, in particular, a laminated piezoelectric member in which piezoelectric layers and internal electrodes are alternately stacked. A piezoelectric actuator having a plurality of columnar piezoelectric elements (piezoelectric element columns) formed thereon, and deforming an elastically deformable diaphragm that forms a wall surface in the liquid chamber by displacement in the d33 or d31 direction of the laminated piezoelectric element; A so-called piezoelectric head that discharges droplets by changing the volume and pressure of a liquid chamber is known.

  With respect to a conventional liquid discharge head and a method for manufacturing the same, an alignment groove is processed using a channel processing blade on the same surface as the channel processing surface of the piezoelectric substrate, and after the channel substrate is created, A method of manufacturing a head is known in which spot machining is performed so that the alignment groove is exposed from the surface, and the channel substrate is cut from the reference position to a predetermined dimension using the alignment groove exposed by the spot machining as a reference position. (Patent Document 1).

  In addition, a stepped portion that is concave in the joining direction is provided on the joint surface of the two piezoelectric members arranged in parallel with each other, and the stepped portions are opposed to each other when the piezoelectric members are arranged in parallel. As related to the side surface, an alignment mark is provided as a reference for position adjustment with respect to the base member in the direction along the joint surface, and at least one of the piezoelectric members is in surface contact with the piezoelectric member in parallel with the base member. In this state, the outer end wall surface is formed with an opening for communicating the stepped portion to the outside of the piezoelectric member on the outer end wall surface side located in the direction orthogonal to the parallel direction of the piezoelectric member in the direction along the bonding surface. A known head is known (Patent Document 2).

  There is also known a head having a dummy groove for preventing the adhesive from protruding into the dividing groove in a joining region with the diaphragm in which the dividing groove for dividing the piezoelectric member into a plurality of piezoelectric element columns is not formed. (Patent Document 3).

JP 2006-341469 A JP 2009-172778 A JP 2003-226019 A

  By the way, in an image forming apparatus, in order to cope with high image quality, droplets are reduced and nozzle density is increased, and in order to cope with high speed, the driving frequency is increased and the number of nozzles per head is increased. Increasing the length of heads typified by line-type heads is increasing.

  Thus, in order to cope with high integration such as high density nozzles, it is necessary to join the position accuracy of the piezoelectric actuator and the diaphragm member, which have a great influence on the droplet discharge characteristics, with high accuracy.

  In this case, as described above, in the configuration in which the opening of the piezoelectric member is provided to improve the detection accuracy of the alignment groove, the piezoelectric member has to be in a complicated shape, which increases the cost. In order to secure an application region of an adhesive for temporarily fixing the piezoelectric member and the diaphragm member, there arises a problem that the size of the piezoelectric member becomes large.

  Furthermore, there is a demand for highly accurate detection even when the width of the alignment groove is narrowed by high integration.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve the detection accuracy of the alignment groove at the time of alignment while achieving downsizing.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A liquid discharge head having a piezoelectric actuator for discharging a droplet by displacing a deformable diaphragm member,
The piezoelectric actuator is
Having at least two piezoelectric members fixed in parallel on the base member;
Stepped portions are provided at both ends of the two piezoelectric members,
The step processed portion at one end of the piezoelectric member is provided with an alignment groove portion used for alignment with the diaphragm member, and the step processed portion at the other end is used for temporary fixing with the diaphragm member. It is an adhesive application area for temporary fixing,
Between the adjacent piezoelectric members, the alignment groove and the adhesive application region are arranged in reverse relation, and the alignment groove and the adhesive application region are arranged on the same end side. The structure overlapped in the direction.

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

According to the liquid ejection head according to the present invention, while achieving the miniaturization, it is possible to improve the detection accuracy of the alignment groove during positioning.

  According to the image forming apparatus of the present invention, since the liquid ejection head according to the present invention is provided, a high quality image can be formed.

FIG. 3 is a schematic exploded perspective view illustrating an example of an embodiment of a liquid discharge head according to the present invention including a nozzle plate according to the present invention. It is sectional explanatory drawing along the liquid chamber longitudinal direction of the head. It is sectional explanatory drawing of an example along the liquid chamber transversal direction of the head. It is sectional explanatory drawing of an example along the liquid chamber transversal direction of the head. It is a plane explanatory view of the piezoelectric actuator concerning a 1st embodiment of the present invention. It is a side explanatory view similarly. It is a plane explanatory view of a piezoelectric actuator concerning a comparative example. It is a side explanatory view similarly. It is a plane explanatory view of a piezoelectric actuator concerning a 2nd embodiment of the present invention. It is a side explanatory view similarly. It is a plane explanatory view of a piezoelectric actuator concerning a 3rd embodiment of the present invention. It is a side explanatory view similarly. It is a plane explanatory drawing used for description to the joining method of the piezoelectric actuator and diaphragm member concerning the present invention. It is a plane explanatory drawing used for explanation to the joining method of the piezoelectric actuator and diaphragm member concerning a comparative example. It is a plane explanatory view of the piezoelectric actuator concerning a 4th embodiment of the present invention. It is a side explanatory view similarly. 1 is a schematic configuration diagram illustrating an overall configuration of a mechanism unit as an example of an image forming apparatus according to the present invention. It is principal part plane explanatory drawing of the mechanism part. It is a whole block diagram which shows the other example of the image forming apparatus which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of a liquid discharge head 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 plate (also referred to as a flow path substrate or a liquid chamber substrate) 1 formed of a SUS substrate and a vibration plate member that forms a vibration plate bonded to the lower surface of the flow path plate 1. 2 and a nozzle plate 3 joined to the upper surface of the flow channel plate 1, and a plurality of nozzles 4 for discharging droplets (liquid droplets) thereby communicate with each other via a nozzle communication channel 5. A plurality of liquid chambers (also referred to as a pressurized liquid chamber, a pressure chamber, a pressurized chamber, and a flow path) 6, a fluid resistance portion 7 that also serves as a supply path for supplying ink to the liquid chamber 6, and this fluid A communication portion 8 communicating with the liquid chamber 6 is formed through the resistance portion 7, and ink is supplied from the common liquid chamber 10 formed in the frame member 17 described later through the supply port 9 formed in the diaphragm member 2 in the communication portion 8. Supply.

  The flow path plate 1 is configured by bonding a flow path plate 1A and a communication plate 1B. The flow path plate 1 is formed by etching the SUS substrate with 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 is formed of the first layer 2A and the second layer 2B, the first layer 2A forms a thin portion, and the first layer 2A and the second layer 2B form a thick portion. . And this diaphragm member 2 has each vibration field (diaphragm part) 2a formed in the 1st layer 2A which forms the wall surface corresponding to each liquid room 6, and in this vibration field 2a, An island-shaped convex portion 2b formed by the thick portions of the first layer 2A and the second layer 2B is provided on the outer surface (the side opposite to the liquid chamber 6), and the vibration region 2a is deformed into the island-shaped convex portion 2b. A piezoelectric actuator 100 according to the present invention including an electromechanical conversion element as a driving means (actuator means, pressure generating means) is arranged.

  The piezoelectric actuator 100 includes a plurality of (here, two) laminated piezoelectric members 12 that are bonded to an adhesive on a base member 13, and the piezoelectric member 12 has one groove 31 processed by half-cut dicing. A required number of piezoelectric columns 12A and 12B are formed in a comb-like shape at a predetermined interval with respect to the piezoelectric member 12. The piezoelectric columns 12A and 12B of the piezoelectric member 12 are the same, but the piezoelectric column that is driven by giving a driving waveform is the driving piezoelectric column 12A, and the piezoelectric column that is used as a simple column without giving the driving waveform is not driven. It is distinguished as the piezoelectric column 12B. The upper end surface (joint surface) of the drive piezoelectric column 12 </ b> A is joined to the island-shaped convex portion 2 b of the diaphragm member 2.

  Here, the piezoelectric member 12 is obtained by alternately stacking the piezoelectric material layers 21 and the internal electrodes 22A and 22B. The internal electrodes 22A and 22B are respectively substantially perpendicular to the end face, that is, the diaphragm member 2 of the piezoelectric member 12. Pulled out to the side surface (surface along the laminating direction), connected to the end face electrodes (external electrodes) 23, 24 formed on this side surface, and applied with a voltage between the end face electrodes (external electrodes) 23, 24, thereby laminating direction Cause displacement.

  The piezoelectric member 12 is connected to an FPC 15 that is a flexible wiring board as a flexible power supply member (wiring member) for applying a driving signal to the driving piezoelectric column 12A. Although not shown, the FPC 15 is mounted with a driver IC (drive circuit) that applies a drive waveform to the drive piezoelectric column 12 </ b> A, and is fixed to the base member 13 with a hot melt adhesive 16.

  Here, as described above, the piezoelectric columns 12A and 12B of the piezoelectric member 12 are the same, and the piezoelectric column to be driven by applying a driving waveform is the driving piezoelectric column 12A, and is simply a column without applying the driving waveform. The piezoelectric column to be used is a non-driving piezoelectric column 12B, and as shown in FIG. 3, the driving piezoelectric column 12A and the non-driving piezoelectric column 12B are alternately used. However, as shown in FIG. A normal pitch configuration in which a piezoelectric column is used as the driving piezoelectric column 12A may be employed.

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

  Further, a frame member 17 formed by injection molding with an epoxy resin or polyphenylene sulfite is joined to the outer peripheral side of the actuator portion composed of the piezoelectric element 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 for supplying recording liquid from the outside to the common liquid chamber 10 is formed. It is connected to an ink supply source such as a cartridge.

  In the liquid discharge head configured as described above, for example, when driven by a pushing method, a drive pulse voltage of 20 to 50 V is selectively applied to the driving piezoelectric column 12A according to an image recorded from a control unit (not shown). By applying the voltage, the piezoelectric column 12A to which the pulse voltage is applied is displaced to deform the vibration region 2a of the vibration plate member 2 in the direction of the nozzle plate 3, and the liquid chamber 6 changes its volume (volume) in the liquid chamber 6. By pressurizing the liquid, droplets are ejected from the nozzle 4 of the nozzle plate 3. As the liquid droplets are discharged, the pressure in the liquid chamber 6 decreases, and a slight negative pressure is generated in the liquid chamber 6 due to the inertia of the liquid flow at this time. Under this state, when the voltage application to the piezoelectric column 12A is turned off, the diaphragm member 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 punching, the liquid discharge head is not limited to the pulling method (a method in which the vibrating plate member 2 is released from the pulled state and pressurized with a restoring force), and the pulling-pushing method (the vibrating plate member 2 is fixed). It can also be driven by a method such as a method of holding at an intermediate position, pulling from this position, and then extruding.

Next, a first embodiment of a piezoelectric actuator according to the present invention will be described with reference to FIGS. 5 is an explanatory plan view of the actuator, and FIG. 6 is an explanatory front view.
In this piezoelectric actuator, two piezoelectric members 12 and 12 are arranged in parallel on a base member 13 such as SUS430, and are bonded and fixed with an acrylic anaerobic adhesive. In the piezoelectric member 12, a plurality of piezoelectric columns 12 a (used generically for the driving columns 12 </ b> A and 12 </ b> B) are formed by grooves 31.

  At both ends of these piezoelectric members 12, step processed portions 103 </ b> A and 103 </ b> B are provided on the joint surface side with the diaphragm member 3. Here, the facing groove 104 facing the diaphragm member 3 of the step processed portion 103A at one end is provided with an alignment groove portion 106 and facing the diaphragm member 3 of the step processed portion 103B at the other end. The facing surface 107 is provided with an adhesive application region (hereinafter referred to as “adhesive application region 107”) to which a temporary fixing adhesive (temporary adhesive) 108 is applied. Yes.

  Further, between the adjacent piezoelectric members 12 and 12, the alignment groove 106 and the adhesive application region 107 are arranged in the reverse relationship, and the alignment groove 106 and the adhesive application region 107 are disposed on the same end side. The piezoelectric members 12 and 12 are disposed so as to overlap in the arrangement direction (short direction) of the piezoelectric members 12 (the longitudinal positions of the piezoelectric members 12 overlap).

  The temporary adhesive 108 is preferably an acrylic or epoxy ultraviolet curable adhesive, but an acrylic instantaneous adhesive or the like may be used.

Here, a comparative example will be described with reference to FIGS.
In this comparative example, an adhesive application region 107 for applying the alignment groove portion 106 and the temporary adhesive 108 is provided on the step processed portions 103 </ b> A and 103 provided at both ends of the piezoelectric member 12.

  If it is configured as in this comparative example, the length of the piezoelectric member 12 becomes long, and the process becomes more complicated.

  On the other hand, in the above embodiment, since only one of the alignment groove portion 106 and the adhesive application region 107 is provided at one end portion of the piezoelectric member 12, the length of the piezoelectric member 12 is shorter than that of the comparative example. can do. Moreover, since the area of a temporary adhesive application area | region can ensure the area more than equivalent to a comparative example, there is no possibility that adhesive strength may fall.

  Furthermore, since the step processed portion 103A in which the alignment groove 106 is formed is located outside the piezoelectric member 12, it is easy to irradiate the step processed portion 103A from the side when performing alignment. Therefore, a large amount of light in the groove 106 can be secured.

  That is, in the comparative example, when the piezoelectric actuator 100 and the diaphragm member 2 are aligned, it is necessary to provide a gap between the two members so as to secure the light from the side, and then pressurize and bond them. Therefore, there is a problem in that it is impossible to manage the position alignment and the positional deviation amount after joining in a state where both members are in contact with each other.

  On the other hand, in the above embodiment, since a large amount of light from the side of the alignment groove portion 106 can be secured, when the piezoelectric actuator 100 and the diaphragm member 2 are aligned, the contact state Alignment can be performed (for example, in a state where pressure is applied with a weak force), and positional deviation in the final pressure state can be minimized. Furthermore, it becomes possible to manage the amount of positional deviation after joining, thereby improving the yield.

  On the other hand, since the adhesive application region 107 is also provided to be opened to the side as in the comparative example, the workability of curing by irradiating ultraviolet rays or the like from the side is not inferior to that of the comparative example.

  In this way, stepped portions are provided at both ends of the two piezoelectric members, an alignment groove portion is provided at the stepped portion at one end of the piezoelectric member, and the stepped portion at the other end is bonded for temporary fixing. Between the adjacent piezoelectric members, the alignment groove portion and the adhesive application region are arranged in an opposite relationship, and the alignment groove portion and the adhesive application region are located on the same end side of the piezoelectric member. By adopting a configuration that overlaps in the arrangement direction, it is possible to improve the detection accuracy of the alignment groove at the time of alignment while achieving downsizing.

Next, a second embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 9 is an explanatory plan view of the actuator, and FIG. 10 is an explanatory front view.
Here, the two piezoelectric members 12 and 12 on the base member 13 are adhesively bonded in a state of being shifted by a shift amount X in the longitudinal direction.

  As described above, the adhesive application region 107 requires a certain area in order to secure the temporary bonding strength. On the other hand, the step processed portion 103A for forming the alignment groove portion 106 only needs to have a length that allows the groove portion 106 to be formed. Therefore, if the groove portion 106 is formed in alignment with the adhesive application region, the total length of the piezoelectric member becomes longer than necessary. End up. Since the piezoelectric member is a high-cost component, and the cost increases in proportion to the volume, the piezoelectric member can be shortened by the amount of shift X by adopting such a configuration, thereby reducing the cost. Can do.

  Further, since the alignment groove portion 106 can be disposed near the edge of the longitudinal end portion of the piezoelectric member 12, illumination for detecting the alignment groove portion 106 is performed when alignment is performed. The position detection accuracy can be increased.

Next, a third embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. 11 is an explanatory plan view of the actuator, and FIG. 12 is an explanatory front view.
Here, an adhesive relief groove 109 is formed in the adhesive application region 107 of the stepped portion 103 </ b> B of the piezoelectric member 12.

  The adhesive releasing groove 109 prevents the excess temporary adhesive 108 from flowing out, and cures the temporary adhesive 108 that has entered the groove 109 (for example, in the case of an ultraviolet curable type, from the vertical direction of FIG. 11). The anchor effect can be obtained by irradiating ultraviolet light and introducing ultraviolet light into the adhesive relief groove 109. Thereby, the application amount of the temporary adhesive 108 can be easily controlled, and the bonding strength of the temporary adhesive 108 can be improved.

  In this case, the adhesive escaping groove 109 can be processed in a common grooving process by making the position in the longitudinal direction of the piezoelectric member equal to that of the alignment groove 106, and the process can be simplified.

Next, a method of joining the piezoelectric actuator according to the present invention to the diaphragm member will be described with reference to FIG. In addition, FIG. 13 is a plane explanatory view shown with an enlarged view of a part enlarged for explaining the joining method.
Here, the piezoelectric actuator according to the first embodiment will be described. In the alignment step with the vibration plate member 2 (nickel electroformed product or SUS / resin film laminate as described above), the vibration member 2 is provided on the vibration plate member 2. An alignment groove 106 (denoted on both sides by 106A and 106B) is aligned with the elongated hole 120.

  At this time, in the X direction (channel pitch direction: nozzle arrangement direction), the edge of the groove 106 is detected and adjusted so as to come to a desired position of the long hole 120. In the Y direction (direction perpendicular to the channel pitch: piezoelectric member arrangement direction), the edge of the piezoelectric member 12 is detected, and adjustment is performed so that the elongated hole 120 is located at a desired position.

  Here, the piezoelectric actuator according to the comparative example will be described. As shown in FIG. 14, in the X and Y directions, the centers of the grooves 106A and 106B and the center positions between the piezoelectric members 12 and 12 are respectively the center positions of the long holes 120. Alignment is performed so that

  In the case of this comparative example, in the alignment in the X direction, since the region 121 that is easily affected by chipping or the like that occurs during the alignment groove processing becomes the detection region, the detection variation increases, and as a result, the misalignment occurs. There is a disadvantage that it occurs.

  On the other hand, in the piezoelectric actuator according to the present invention, the detection variation can be reduced by increasing the edge length A of the groove 106 to be detected. In the case of a highly integrated actuator, the width of the alignment groove 106 is also narrowed. Therefore, in order to reduce detection variation, it is necessary to use a high-magnification camera, but this is detected when a high-magnification camera is used. Since the area is also small, the length of the long hole shown in FIGS. 13 and 14 is also limited. Thus, in the long hole with the limited length, the configuration as shown in FIG. 13 that can ensure the long groove edge length A within the limited length is particularly preferable.

Next, a fourth embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. FIG. 15 is an explanatory plan view of the actuator, and FIG. 16 is an explanatory front view.
Here, the shape of the adhesive relief groove 109 is different from that of the alignment groove 106. In consideration of the workability of the groove processing, the alignment groove portion 106 may be formed to extend to the adjacent adhesive application region 107, or conversely, the adhesive relief groove portion 109 is adjacent to the opposite surface. It may be extended to 104.

  Needless to say, the configuration (width, depth, etc.) and process (processing speed, etc.) required for the alignment groove 106 and the adhesive relief groove 109 are different, and they may not be formed in the same processing process. Specifically, the alignment groove portion 106 needs to be processed at a low speed in order to suppress the occurrence of the above-described chipping as much as possible. In addition, a certain amount of depth is required to ensure the contrast of edge detection. On the other hand, the adhesive relief groove 109 needs a width or number rather than a depth in order to increase the volume for holding the adhesive. In order to process a plurality of pieces, it is necessary to increase the processing speed in consideration of the longer processing time.

  Therefore, it is preferable that both the groove portions are provided independently, and this makes it possible to surely achieve both the suppression of the flow of the adhesive and the securing of the joining position accuracy. Further, by extending both grooves to other arranged piezoelectric members, groove processing can be formed in a lump and the process can be simplified.

  Since the liquid discharge head described above includes the piezoelectric actuator according to the present invention as the piezoelectric actuator 100, variations in droplet discharge characteristics are reduced.

  Note that a head-integrated liquid cartridge (cartridge-integrated head) can be obtained by integrating the above-described liquid discharge head and a tank that supplies liquid to the liquid discharge head.

Next, an example of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention will be described with reference to FIGS. FIG. 17 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 18 is a plan view for explaining a main portion of the mechanism portion.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and slave guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 221A and 221B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

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

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

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

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

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

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

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

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

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

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

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 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 discharge head according to the present invention, there is little variation in the droplet discharge characteristics, and a high-quality image can be formed.

Next, another example of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 19 is a schematic configuration diagram of the entire mechanism unit of the apparatus.
This image forming apparatus is a line type image forming apparatus, has an image forming unit 402 and the like inside the apparatus main body 401, and can supply a large number of recording media (sheets) 403 on the lower side of the apparatus main body 401. A paper tray 404 is provided, a sheet 403 fed from the sheet feeding tray 404 is taken in, a required image is recorded by the image forming unit 402 while the sheet 403 is conveyed by the conveying mechanism 405, and then the side of the apparatus main body 401. The paper 403 is discharged to a paper discharge tray 406 attached to the printer.

  Also, a duplex unit 407 that can be attached to and detached from the apparatus main body 401 is provided, and when performing duplex printing, the sheet 403 is conveyed into the duplex unit 407 while being transported in the reverse direction by the transport mechanism 405 after one-side (front) printing is completed. Then, the other side (back side) is sent back to the transport mechanism 405 as the printable side, and the paper 403 is discharged to the paper discharge tray 406 after the other side (back side) printing is completed.

  Here, the image forming unit 402 is, for example, four full-line liquids according to the present invention that discharge droplets of each color of black (K), cyan (C), magenta (M), and yellow (Y). The recording heads 411k, 411c, 411m, and 411y (which are referred to as “recording heads 411” when the colors are not distinguished) are configured with ejection heads, and each recording head 411 has a nozzle surface on which nozzles for ejecting droplets are formed downward. The head holder 413 is attached.

  In addition, a maintenance / recovery mechanism 412k, 412c, 412m, 412y (referred to as “maintenance / recovery mechanism 412” when colors are not distinguished) is provided to maintain and recover the performance of the head corresponding to each recording head 411. During the head performance maintenance operation such as wiping processing, the recording head 411 and the maintenance / recovery mechanism 412 are relatively moved so that the capping member constituting the maintenance / recovery mechanism 412 faces the nozzle surface of the recording head 411.

  Here, the recording head 411 is arranged to eject droplets of each color in the order of blank, cyan, magenta, and yellow 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 a predetermined interval can be used, or a head and a liquid cartridge for supplying ink to the head are integrated. Or a separate body.

  The paper 403 in the paper feed tray 404 is separated one by one by a paper feed roller (half-moon roller) 421 and a separation pad (not shown) and fed into the apparatus main body 401, and is registered along the guide surface 423 a of the transport guide member 423. It is sent between 425 and the conveyor belt 433, and is sent to the conveyor belt 433 of the conveyor mechanism 405 via the guide member 426 at a predetermined timing.

  In addition, the conveyance guide member 423 is also formed with a guide surface 423 b for guiding the paper 403 sent out from the duplex unit 407. Further, a guide member 427 for guiding the sheet 403 returned from the transport mechanism 405 to the duplex unit 407 during duplex printing is also provided.

  The conveyance mechanism 405 includes an endless conveyance belt 433 that is stretched between a conveyance roller 431 that is a driving roller and a driven roller 432, a charging roller 434 that charges the conveyance belt 433, and an image forming unit 402. A platen member 435 that maintains the flatness of the conveying belt 433 at the opposite portion, a pressing roller 436 that presses the paper 403 fed from the conveying belt 433 against the conveying roller 431 side, and other ink (not shown) that adheres to the conveying belt 433. It has a cleaning roller made of a porous body or the like as a cleaning means for removing.

  On the downstream side of the transport mechanism 405, a paper discharge roller 438 and a spur 439 for sending the paper 403 on which an image is recorded to the paper discharge tray 406 are provided.

  In the image forming apparatus configured as described above, the conveyance belt 433 moves in the direction indicated by the arrow, and is charged by contact with the charging roller 434 to which a high potential application voltage is applied. The conveyance belt is charged to this high potential. When the sheet 403 is fed onto the sheet 433, the sheet 403 is electrostatically attracted to the conveyance belt 433. In this way, the sheet 403 that is strongly adsorbed to the transport belt 433 is calibrated for warpage and unevenness, and forms a highly flat surface.

  Then, the paper 403 is moved around the conveyor belt 433 and droplets are ejected from the recording head 411, whereby a required image is formed on the paper 403, and the paper 403 on which the image has been recorded is the paper discharge roller 438. As a result, the paper is discharged to the paper discharge tray 406.

  As described above, since the image forming apparatus includes the liquid discharge head according to the present invention, there is little variation in the droplet discharge characteristics, and a high-quality image can be formed at high speed.

  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.

1 Channel plate (channel substrate)
2 Vibration plate member 3 Nozzle plate 4 Nozzle 6 Liquid chamber 10 Common liquid chamber 12 Piezoelectric member 12A Driving column 12B Non-driving column 12a Piezoelectric column 13 Base member 103A, 103B Stepped portion 104 Opposing surface 106 Positioning groove portion 107 Adhesive application Area (opposite surface)
108 Temporary adhesive 109 Adhesive relief groove

233 Carriage 234a, 234b Recording head 411k, 411c, 411m, 411y Recording head

Claims (5)

A liquid discharge head having a piezoelectric actuator for discharging a droplet by displacing a deformable diaphragm member,
The piezoelectric actuator is
Having at least two piezoelectric members fixed in parallel on the base member;
Stepped portions are provided at both ends of the two piezoelectric members,
The step processed portion at one end of the piezoelectric member is provided with an alignment groove portion used for alignment with the diaphragm member, and the step processed portion at the other end is used for temporary fixing with the diaphragm member. It is an adhesive application area for temporary fixing,
Between the adjacent piezoelectric members, the alignment groove and the adhesive application region are arranged in reverse relation, and the alignment groove and the adhesive application region are arranged on the same end side. A liquid discharge head characterized by overlapping in a direction. The liquid ejection head according to claim 1, wherein the adjacent piezoelectric members are fixed while being displaced in a longitudinal direction. The liquid discharge head according to claim 1, wherein a groove portion is also provided in a step processed portion serving as the adhesive application region. 4. The liquid discharge head according to claim 3, wherein a shape of a groove formed in the step processed portion serving as the adhesive application region is different from a shape of the alignment groove. 5. An image forming apparatus comprising the liquid discharge head according to claim 1 .

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