JP5327431B2 - Piezoelectric actuator, liquid discharge head, and image forming apparatus - Google Patents

Description

  The present invention relates to a piezoelectric actuator, 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 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, “image forming apparatus” means an apparatus that forms an image by discharging liquid onto 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). “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 and the like are also included.

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

  Also, some piezoelectric heads include a piezoelectric actuator in which a plurality of piezoelectric element members formed with a plurality of piezoelectric element columns are arranged in a column arrangement direction on a base member in order to cope with an increase in the length of the head. .

  In such a piezoelectric head, an electrode of a flexible wiring board such as an FPC (flexible printed cable) is joined to an external electrode (also referred to as an end face electrode) obtained by pulling an internal electrode to an end face using, for example, a laminated piezoelectric element. A drive signal corresponding to an image signal is given to each piezoelectric element.

Conventionally, regarding the bonding configuration between the actuator of the head and the FPC, in the electrostatic head, Patent Document 1 discloses that there is a defect in the inter-electrode portion of the FPC in order to reduce the occurrence of bonding failure due to expansion during FPC bonding heating. The structure which provides a removal part or a slit is disclosed.
JP 2002-67337 A

Further, in Patent Document 2, when FPCs corresponding to the number of ink cartridges are installed, a space is required, and the assembly work becomes complicated. Therefore, the FPC is branched into a plurality of branch portions, bent in the middle, and each branch is made. The structure which arrange | positions the space | interval of a part to the arrangement space | interval of a contact member group is disclosed.
JP 2006-116793 A

  Note that an electrical connection is made between an electrode (which is also referred to as a “first electrode”) provided on a wiring board such as an FPC and an external electrode (which is also referred to as a “second electrode”) of the piezoelectric element. As a method, for example, a metal is interposed between the first electrode and the second electrode, both the electrodes are brought into close contact with a laser-transmitting rigid member such as glass, and the metal is melted by laser light. A method of welding and joining the second electrode with a metal, and a method of welding the first electrode and the second electrode with a metal by melting the metal by thermocompression bonding such as a heater are known. ing.

  As described above, when a piezoelectric actuator is configured by arranging a plurality of piezoelectric element members formed with a plurality of piezoelectric element columns on the base member in the column arrangement direction, the plurality of piezoelectric element members are arranged on the base member. When shifted in a direction perpendicular to the direction, a step is generated between the plurality of piezoelectric element members.

  Therefore, when the second electrode of one FPC is directly connected to the first electrodes of the piezoelectric element columns of the plurality of piezoelectric element members, there is a problem that poor bonding occurs at a step portion between the piezoelectric element members. In this case, it is conceivable to join a plurality of FPCs. However, when a plurality of FPCs are used, there is a problem that the FPCs may interfere with each other between the piezoelectric element members.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce poor bonding due to a step between a plurality of piezoelectric element members when a single flexible wiring board is directly connected to the plurality of piezoelectric element members. And

In order to solve the above problems, the piezoelectric actuator according to the present invention is:
A plurality of piezoelectric element members formed with a plurality of piezoelectric element columns are arranged side by side along the column arrangement direction on the base member,
One flexible wiring board extending over the plurality of piezoelectric element members is directly connected to the plurality of piezoelectric element columns ,
In the tip portion of the flexible wiring board that is directly connected to the piezoelectric element column, a cut is formed corresponding to the position between the plurality of piezoelectric element members ,
The height of the connecting surface to the piezoelectric element columns on both sides of the incision was different Do that configuration.

  Here, the cut may have a wedge shape or a rectangular shape.

  The liquid discharge head according to the present invention includes the piezoelectric actuator according to the present invention.

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

According to the piezoelectric actuator according to the present invention, it is possible to reduce the defective bonding due to the step between multiple piezoelectric elements members.

  According to the liquid ejection head according to the present invention, since the piezoelectric actuator according to the present invention is provided, the reliability can be improved.

  According to the image forming apparatus according to the present invention, since the liquid ejection head according to the present invention is provided, the reliability can be improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of a piezoelectric actuator of the present invention will be described with reference to FIGS. 1 is an explanatory front view of the actuator, FIG. 2 is an explanatory plan view of the actuator, FIG. 3 is an explanatory side view of the actuator, and FIG. 4 is an explanatory perspective view for explaining the joining of the piezoelectric element member and the FPC of the actuator. 5 is an enlarged front explanatory view of the main part.

  The piezoelectric actuator 1 includes two rows of piezoelectric element members 2 in which a plurality of piezoelectric element columns 12 are formed and arranged side by side with a predetermined gap 10 along a column arrangement direction on a base 3 member. The FPC 4 that is a flexible wiring board is directly connected to each piezoelectric element column 12 of each piezoelectric element member row and has a front end portion (connection portion) of the FPC 4 that is directly connected to the piezoelectric element column 12. ) Is formed with a wedge-shaped cut (slit) 5 corresponding to the space between the plurality of piezoelectric element members 2 and 2 (here, the gap 10).

  Here, as shown in FIG. 3, the piezoelectric element member 2 is formed by alternately laminating piezoelectric material layers 21 and internal electrodes 22a and 22b, and the internal electrodes 22a and 22b are drawn out to the end faces, respectively. Are connected to the end face electrodes (external electrodes) 23a, 23b formed on the substrate, and a voltage is applied to the end face electrodes (external electrodes) 23a, 23b to cause displacement in the stacking direction. As shown in FIGS. 4 and 5, the piezoelectric element member 2 is formed by forming grooves by half-cut dicing to form a required number of piezoelectric element columns 11 for one piezoelectric element member 2. The plurality of piezoelectric element members 2 are arranged with the gap 10 as described above, but may be arranged without the gap 10.

  As shown in FIGS. 4 and 5, the connection electrode (first electrode) of the FPC 4 by the solder member 32 to give a drive signal to the external electrode (second electrode) 23a of the piezoelectric element column 11 of the piezoelectric element member 2. ) 31 is directly joined with a laser or the like, and a driving circuit (driver IC) 6 for selectively applying a driving waveform to the piezoelectric element column 11 of the piezoelectric element member 2 is mounted on the FPC 4. Yes. Note that the external electrodes 23b of all the piezoelectric element columns 12 are electrically connected in common and connected to the common wiring of the FPC 4.

  Here, as shown in FIG. 2, the direction (arrow B direction: piezoelectric element member short direction) orthogonal to the column arrangement direction (arrow A direction: piezoelectric element member longitudinal direction) between the piezoelectric element members 2 in each row. ), The step is absorbed by the notch 5 even if there is a step at the joint surface (the outer surface of the external electrode 23a) between the plurality of piezoelectric element members 2 to which one FPC 4 is directly connected. Thus, each piezoelectric element column 11 of each piezoelectric element member 2 and the FPC 4 can be reliably connected, and the reliability of electrical connection is improved.

  In the above embodiment, the FPC 4 is used. However, the flexible wiring board may be a thin film provided with a plurality of electrodes arranged in parallel with each other. For example, TAB (Tape Automated Bonding) is used. Can also be used.

  Further, the solder member 32 is melted by irradiation of laser light that can pass through each connection electrode 31 (metal member) and the resin member of the FPC 4 body, that is, the connection member 31 (metal member) and the resin member of the FPC 4 body. Any material having a lower melting point than that of the material having conductivity may be used as long as it does not contain lead (Pb). For example, the solder member 32 may be solder containing tin (Sn) and bismuth (Bi) as main components. Since lead is not contained, it is effective from the viewpoint of environmental protection, and the solder member 32 mainly composed of tin (Sn) and bismuth (Bi) has a very low melting point among non-lead members. Therefore, the first electrode and the second electrode can be easily welded without damaging the FPC 4 and the piezoelectric element member 2. Furthermore, the solder does not have to be formed in advance on the FPC or the piezoelectric element.

  In this way, a plurality of piezoelectric element members formed with a plurality of piezoelectric element columns are arranged side by side along the column arrangement direction on the base member, and one flexible wiring board is directly connected to the piezoelectric element columns. The front end portion of the flexible wiring board directly connected to the substrate has cuts correspondingly between the plurality of piezoelectric element members, so that it is possible to reduce poor bonding due to a step between the plurality of piezoelectric element members. .

Next, a second embodiment of the piezoelectric actuator of the present invention will be described with reference to FIG. FIG. 6 is an explanatory front view of the actuator.
Here, a rectangular notch (slit) 5 is formed between the plurality of piezoelectric element members 2 and 2 at the front end portion (connection portion) of the FPC 4. Even if comprised in this way, the effect similar to the said 1st Embodiment can be acquired.

Next, an example of a wiring member joining apparatus for connecting the piezoelectric element member of the piezoelectric actuator and the FPC will be described with reference to FIG. In addition, the figure is the typical block diagram seen from the side for demonstrating the structure of the same wiring member joining apparatus.
The wiring member joining apparatus 10 electrically joins a plurality of parallel connection electrodes 31 (first electrodes) provided on the FPC 4 and a plurality of parallel second electrodes (external electrodes 23a) of the piezoelectric element member 2. It is. 7 is the height direction Z-axis direction when viewed from the front, the plane orthogonal to this is the XY plane, and the width direction (lateral direction) when FIG. 7 is viewed from the front is the Y-axis direction.

  In this wiring member joining apparatus 310, a base 311 is provided with a first member holding mechanism 312, a second member holding mechanism 313, a laser irradiation mechanism 314, a camera 315, and an air path forming mechanism 316. The drive control is centralized by a control mechanism (not shown).

  The first member holding mechanism 312 includes a bonded XY direction adjusting unit 317 provided on the base 311, a bonded Z axis direction adjusting unit 318 mounted on the bonded XY direction adjusting unit 317, and the bonded Z axis direction. And an adjustment stage 319 mounted on the adjustment unit 318.

  Although not shown in the drawings, the bonding XY direction adjusting unit 317 is supported by an X-axis driving unit that is supported by a guide shaft extending in the X-axis direction and a guide shaft that is driven by the Y-axis direction. The Y-axis drive unit is configured to be movable along the XY plane. A joining Z-axis direction adjusting part 318 is attached to the joining XY direction adjusting part 317 so as to be movable together with the joining XY direction adjusting part 317.

  Although not shown in the drawing, the bonding Z-axis direction adjusting unit 318 is configured to be freely movable along the Z-axis direction with respect to the bonding XY direction adjusting unit 317. It is possible to move together with the bonded Z-axis direction adjusting unit 318, that is, to move to a desired position on the base 311 by the bonded XY direction adjusting unit 317 and the bonded Z-axis direction adjusting unit 318. The adjustment stage 319 is attached to the bonding Z-axis direction adjustment unit 318.

  The adjustment stage 319 is a plate-like member provided so as to extend along the XY plane at the upper end position of the bonding Z-axis direction adjustment unit 318. An upper surface of the adjustment stage 319 along the XY plane serves as a mounting surface 319a of the FPC 4 that is the first wiring member, and a plurality of positioning pins 320 (only one is shown in the figure) projecting from the mounting surface 319. In addition, the FPC 4 placed on the placement surface 319a can be sucked and held. Each positioning pin 320 roughly determines the placement position of the FPC 4 placed on the placement surface 319a of the adjustment stage 319.

  With the above-described configuration, the first member holding mechanism 312 can adjust the FPC 4 sucked and held on the mounting surface 319a of the adjustment stage 319 to a desired position while extending along the XY plane. .

  A second member holding mechanism 213 is provided to fix and hold the piezoelectric element member 2 joined to the FPC 4.

  The second member holding mechanism 313 has a second member mounting table 322 attached to a fixed base 321 provided on the base 311, and a plurality of piezoelectric element members 2 are placed on the second member mounting table 322. The joined base member 3 is fixed. The second member holding mechanism 313 is located above the joint portion of the piezoelectric element member 2 of the base member 3 that has been sucked and held, and the joint portion of the FPC 4 that is sucked and held in a state of being approximately positioned by the first member holding mechanism 312. As described above, the relative positional relationship with the first member holding mechanism 312 is set.

  A laser irradiation mechanism 314 is provided in order to irradiate the joint with laser light. The laser irradiation mechanism 314 is attached to the base 311 so as to be always fixed at a fixed position via the mounting arm 323, and includes a laser XY direction adjustment unit 324, a laser Z axis direction adjustment unit 325, and a laser irradiation unit. 326.

  Although not shown, the laser XY direction adjusting unit 324 is supported by an X-axis drive unit that is supported by a guide shaft extending in the X-axis direction and a guide shaft that is driven by the Y-axis direction. The Y-axis driving unit is movable along the XY plane. A laser Z-axis direction adjusting unit 325 is attached to the laser XY direction adjusting unit 324 so as to be movable together with the laser XY direction adjusting unit 324.

  Although not shown, the laser Z-axis direction adjustment unit 325 is configured so as to be freely movable along the Z-axis direction with respect to the laser XY direction adjustment unit 324. It is possible to move together with the laser Z-axis direction adjusting unit 325, that is, to move to a desired position on the base 311 by the laser XY direction adjusting unit 324 and the laser Z-axis direction adjusting unit 325. The laser irradiation unit 326 is attached to the laser Z-axis direction adjustment unit 325.

  The laser irradiation unit 326 can emit laser light L, and a semiconductor laser is employed. The laser irradiation unit 326 can emit the laser light L along the Z-axis direction regardless of the position moved by the laser XY direction adjustment unit 324 and the laser Z-axis direction adjustment unit 325. Is attached. A camera 315 is provided so as to be positioned between the laser irradiation unit 326 and the piezoelectric element member 2 of the base member 3 that is sucked and held by the second member holding mechanism 313.

  Although not shown, the camera 315 has its optical axis positioned on the optical axis of the laser light L emitted from the laser irradiation unit 326 regardless of the movement of the laser irradiation unit 326 (for example, the laser irradiation unit 326). Is fixed to the laser Z-axis direction adjusting portion 325 so as to be interlocked with each other. For this reason, the camera 315 can image the vicinity of the irradiation region of the laser light L without hindering the irradiation of the laser light L by the laser irradiation unit 326.

  The air path forming mechanism 316 holds the air path forming plate 327 between the camera 315 and the piezoelectric element member 2 of the base member 56 held by suction by the second member holding mechanism 313.

  The air path forming mechanism 316 includes an air path XY direction adjusting unit 328 and an air path forming plate 327. Although not shown, the air passage XY direction adjusting unit 328 is driven by an X-axis drive unit that is supported by a guide shaft extending in the X-axis direction and a guide shaft that extends in the Y-axis direction. It is comprised by the supported Y-axis drive part, and is movable along an XY plane.

  An air passage forming plate 327 is detachably fixed and held on the air passage XY direction adjusting portion 328 so as to be movable together with the air passage XY direction adjusting portion 328. The air path XY direction adjusting unit 328 includes a laser beam L emitted from the laser irradiation unit 326 and a camera 315 corresponding to the air path forming plate 327 having a plate shape as a whole extending along the XY plane. The air path forming plate 327 is fixedly held so that the optical axis of the laser beam passes through the inside of the laser transmission plate portion 341 and the air path forming notch 343 provided on the air path forming plate 327.

  Further, the air path XY direction adjusting unit 328 moves the air path forming plate with respect to the laser beam L and the optical axis of the camera 315 when the laser irradiation unit 326 is moved by the laser XY direction adjusting unit 324 and the laser Z axis direction adjusting unit 325. It is configured to be interlocked with the position of the laser irradiation unit 326 so that the positional relationship of 327 is maintained.

  Accordingly, the laser light L emitted from the laser irradiation unit 326 is transmitted through the air path forming plate 327 regardless of the position of the laser irradiation unit 326 to be moved, and between the FPC 4 and the piezoelectric element member 2 of the base member 3. The junction can be irradiated.

  Here, a semiconductor laser is used as the laser irradiation unit, but the absorption ratio to the portion to be irradiated (solder member 32 in each of the above embodiments) is good and the transmittance of the flexible wiring board is good. In this case, for example, a continuously emitted YAG (Yttrium / Aluminum / Garnet) laser may be used.

  However, since a semiconductor laser is used as the laser light, it is inexpensive and easy to control, so that the joining work can be performed inexpensively and appropriately. Further, since the semiconductor laser has a high transmittance to the resin material, the electrodes can be bonded without damaging the bonding member (flexible wiring board, piezoelectric element member).

  In addition, if the width of the common electrode and the individual electrode of the flexible wiring board is the same, there is no need to change the laser irradiation output and speed in joining the piezoelectric element member and the flexible wiring board, and the amount of heat given at the time of joining. Therefore, it is possible to reduce the expansion and contraction of FPC, reduce the occurrence of bonding failure, and reduce the heating time because the FPC is not damaged at the common electrode at the end and the applied heat is small. Can improve production efficiency.

Next, a comparative example with the present invention will be described with reference to FIGS. 8 is an explanatory front view of the actuator of the comparative example, and FIG. 9 is an explanatory plan view.
In the present invention, as described above, the cuts 5 are formed in the FPC (flexible wiring board) corresponding to the plurality of piezoelectric element members. In this comparative example, a plurality of steps are formed without forming the cuts in the FPC 4. The connection electrode 31 of the FPC 4 is joined and connected to the external electrode 23 a of the piezoelectric element column of the piezoelectric element member 2.

  When there is a step at the joint between the piezoelectric element members in which a plurality of piezoelectric element members formed with a plurality of piezoelectric element columns are arranged in the column alignment direction, the electrodes 31 and 23a of the FPC 4 and the piezoelectric element member 2 are connected to each other. When joining, as a heating method of the solder member 32, in the case of a contact heating method using a heater or the like, there is a possibility that a joining failure may occur at the joint of the piezoelectric element, and a non-contact heating method such as a laser is used. Is suitable. In addition, the FPC 4 and the piezoelectric element member 2 may be bonded to each other with a member such as glass, but it is preferable that the FPC 4 and the piezoelectric element member 2 are bonded with a laser while the FPC 4 and the piezoelectric element member 2 are bonded to each other by air pressure.

  An example of a wiring member bonding apparatus that performs such bonding will be described with reference to FIGS. 10 is a schematic configuration diagram viewed from the side for explaining the configuration of the wiring member joining apparatus, FIG. 11 is an enlarged explanatory diagram of the main part, and FIG. 12 is a perspective explanatory diagram of the air suppression mechanism. .

  The wiring member bonding apparatus 410 has a structure in which a laser irradiation mechanism 345 and an air suppression mechanism 370 are integrated. As shown in FIGS. 11 and 12, the air suppression mechanism 370 is configured by a cylindrical body in which one end 370 a side is tapered and the other end 370 b side is cylindrical. The air suppression mechanism 370 has one end 370a having a diameter capable of locally blowing gas, and an introduction port 370c provided in the vicinity of the other end 370b. Compressed air forming means 363 is connected to the introduction port 370c.

  The air suppression mechanism 370 has the other end 370b on the bottom surface of the laser irradiator 326 so that its central axis (including the center of the opening of the one end 370a) is coaxial with the laser light L emitted from the laser irradiator 326. The surface of the laser beam L is hermetically attached to the laser beam L and cooperates with the laser irradiation unit 326 to define a local pressure air passage 371 that leads from the introduction port 370c to the one end 370a.

  In this local pressing air path 371, when gas is introduced from the compressed air forming means 363 through the inlet 370 c, the gas is blown out from the one end 370 a, and is coaxial with the laser light L and Z axis direction lower side (FPC 4 side). A gas flow toward the can be formed. For this reason, the air suppression mechanism 370 constitutes a fluid pressure local close contact means in cooperation with the compressed air forming means 363 and the laser irradiation unit 326 connected to the introduction port 370c.

In this laser irradiation mechanism 345, when the laser light L is emitted from the laser irradiation unit 326 while the gas is sent from the compressed air forming means 363 into the local pressing air path 371, the gas blown out from one end 370a of the air suppression mechanism 370 However, it hits the upper surface of the FPC 4 locally at a position coinciding with the axis of the laser beam L from above the FPC 4, and the periphery of the portion irradiated with the laser beam L in the FPC 4 is locally pressed toward the piezoelectric element member 2. Is done.

  From this, the local gas flow referred to here means at least irradiation for joining the laser beam L emitted from the laser irradiation unit 326 (when irradiating the solder member 32 to melt). The FPC 4 can be locally pressed toward the piezoelectric element member 2 in order to bring the first electrode 31 and the second electrode 23a into close contact with each other in the irradiation region (size and size of the irradiation spot).

  In this wiring member joining apparatus 410, first, as shown by a two-dot chain line in FIG. 10, the camera 355 is positioned above each connection electrode 31 of the FPC 4 (the external electrode 23a of the piezoelectric element member 2) to connect the FPC 4. The position of the adjustment stage 319 of the first member holding mechanism 312 is adjusted based on the image from the camera 355 so that the electrode 31 and the external electrode 23a of the piezoelectric element member 2 face each other in an appropriate state.

  After this position adjustment, as shown by a solid line in FIG. 10, the laser irradiation unit 326 is moved to a position where the laser light L can be irradiated so as to join each connection electrode 31 and each external electrode 23a that are appropriately opposed to each other. . The position adjustment of the laser irradiation unit 326 at this time may be performed by, for example, a mechanical setting by the laser XY direction adjustment unit 324 and the laser Z axis direction adjustment unit 325. You may perform based on an image | video.

  Thus, after setting each position, in the state which emitted laser beam L from the laser irradiation part 326, sending the gas from the compressed air formation means 363 into the local pressing air path 371, the joining location (solder member 32) (scanning of the irradiation position along the X-axis direction) is performed by irradiation with the laser beam L. As a result, each connection electrode 31 and each external electrode 23a are irradiated with the laser beam L at a location where gas is locally blown from the compressed air forming means 363 and is in close contact with the laser light L. Since the portions are moved in the X-axis direction in which the connection electrodes 31 and the external electrodes 23a are arranged in parallel, they are joined by the laser light L in a state of being in close contact with each other.

  Thereby, the FPC 4 and the piezoelectric element member 2 are electrically joined in a stable state with each connection electrode 31 and each external electrode 23a facing each other appropriately. At this time, in the wiring member bonding apparatus 410, since the suction means 364 is provided, the flow of the gas blown out from the one end 370a of the air suppression mechanism 370 and locally blown onto the upper surface of the FPC 4 is made smoother. can do.

  As described above, the wiring member bonding apparatus 410 has a configuration in which the connection electrode 31 and the external electrode 23a are bonded in close contact with a gas flow that blows locally on the upper surface of the FPC 4, and thus the FPC 4 and the piezoelectric element member 2 are bonded. The connection electrodes 31 and the external electrodes 23a can be joined in a stable and appropriate state in a state in which contamination due to fume is prevented while preventing unintended thermal deformation.

  In particular, since only the periphery of the irradiation region of the laser beam L from the laser irradiation mechanism 345 in the FPC 4 is locally pressed and joined to the connection electrode 31 and the external electrode 23a, each connection electrode 31 is surely secured with a small air volume. And each external electrode 23a can be joined. Further, since only the vicinity of the joint portion is brought into close contact, the gas existing between the FPC 4 and the piezoelectric element member 2 can be efficiently released to the vicinity of the close portion between the FPC 4 and the piezoelectric element member 2. So it can be more closely in close contact. Further, since the local gas is blown from the same direction as the laser light L on the axis of the laser light L, the local gas can be reliably blown to the irradiation region of the laser light L. In particular, for example, even when the interval between the laser irradiation unit 426 and the aiming position of the laser beam L is changed in accordance with the change of the bonding target, without changing the spray position by the fluid pressing local close-in means, A local gas can be reliably blown to the irradiation region of the laser beam L.

  In addition, since the fluid pressing local close contact means provided in the laser irradiation unit 326 forms a local gas flow to be sprayed to the irradiation region of the laser light L, the local spraying position is set to the laser irradiation unit 326. It is possible to reliably follow the movement. In addition, since the irradiation region of the laser beam L, that is, only the vicinity of the joining portion is brought into close contact with each other, local gas is used as the irradiation region of the laser beam L regardless of changes in the size and the like of the FPC 4 and the piezoelectric element member 2. Can spray reliably.

  Even in such a comparative example, the level difference can be absorbed to some extent. However, according to the present invention, since the notch is formed in the portion corresponding to the level difference, it is possible to prevent the bonding failure due to the level difference more reliably.

  Next, an embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 13 is an external perspective view of the liquid discharge head, FIG. 14 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber along the line AA in FIG. FIG. 3 is a cross-sectional explanatory view along the shorter direction of the liquid chamber (the 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) that is liquid to the pressurized liquid chamber 106, and a common liquid that supplies recording liquid to the plurality of pressurized liquid chambers 106. A chamber 108 is formed. The recording liquid is supplied to the common liquid chamber 108 from a liquid 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 side of the diaphragm member 102 (on the side opposite to the pressurized liquid chamber 106). Similar to the piezoelectric actuator 1 described above, the piezoelectric actuator 110 includes a plurality of piezoelectric element members 112 and a single flexible wiring board, for example, an FPC 113, that supplies power to each piezoelectric element member 112 in a row. The piezoelectric element members 112 are joined and arranged in a row on a common base member 114.

  The piezoelectric element member 112 forms an even number of piezoelectric element pillars 111 at a predetermined pitch via the slit grooves 115 by performing slit processing (groove processing) without being divided. The interval 120 between the piezoelectric element columns 111 of the piezoelectric element member 112 is also arranged as the groove width of the slit groove 115. Each piezoelectric element column 111 of the piezoelectric element member 112 is used as a piezoelectric element column (driving piezoelectric element column) 111A that drives every other piezoelectric element column and a non-driven piezoelectric element column (non-driving piezoelectric element column) 111B.

  The FPC 113 has the same configuration as the FPC 4 of the piezoelectric actuator 1 described above, and has connection electrodes (not shown) arranged corresponding to every other driving piezoelectric element column 111A of the piezoelectric element member 112, and the driving piezoelectric element A notch is formed between the piezoelectric element members 112 and 112 on the tip end side connected to the external electrode of the column 111A.

  The driving piezoelectric element column 111A 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 111B is bonded to the thick portion 102D corresponding to the liquid chamber interval wall portion 106A. The agent 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. The internal electrodes are alternately electrically connected to the individual electrodes and the common electrodes (not shown) which are the end electrodes (external electrodes) on the end faces, respectively, and the power supply described above is applied to these individual electrodes and the common electrodes. The member 113 is soldered. The diaphragm region 102A is displaced by the expansion and contraction of the driving piezoelectric element column 111A 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 111A and charging is performed, the piezoelectric element column 111A expands. When the electric charge charged to the piezoelectric element column 111A is discharged, the piezoelectric element column 111A contracts in the opposite direction.

  It should be noted that the ink in the pressurized liquid chamber 106 may be pressurized using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element member 112 (drive piezoelectric element column 111A), or the d31 direction as the piezoelectric direction of the piezoelectric element member 112. 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 111 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 as described above, for example, the drive piezoelectric element column 111A contracts by lowering the voltage applied to the drive piezoelectric element column 111A 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 111A is increased to stack the driving piezoelectric element columns 111A. 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 driving piezoelectric element column 111A 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.

  Thus, since the liquid discharge head includes the piezoelectric actuator according to the present invention, the bonding reliability between the flexible wiring board and the piezoelectric element member is improved, and a highly reliable head can be obtained.

Next, an example of an image forming apparatus according to the present invention will be described with reference to FIG. FIG. 16 is a schematic configuration diagram of the entire mechanism 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. The head holder 213 is attached.

  Further, maintenance recovery mechanisms 212k, 212c, 212m, and 212y for maintaining and recovering the head performance corresponding to each recording head 211 are provided (referred to as “maintenance recovery mechanism 212” when colors are not distinguished), and purge processing, 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, it is possible to form an image at high speed using a recording head that can be obtained at low cost and high reliability. it can. In addition, since the recording head in the image forming apparatus and the liquid ejection apparatus constituted by the portion for driving the recording head are provided with the recording head comprising the liquid ejection head according to the present invention, the cost is low and the reliability is high. It is possible to perform liquid discharge with which the property can be obtained.

  In the above-described embodiment, an example in which the present invention is applied to an image forming apparatus having a printer configuration has been described. 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 be applied to an image forming apparatus using a recording liquid or a fixing processing liquid that is a liquid other than ink. In the above-described embodiment, the line type liquid discharge head and the line type image forming apparatus are described. However, the serial type image forming apparatus and the liquid discharge head used therefor can also be configured.

It is front explanatory drawing of 1st Embodiment of the piezoelectric actuator of this invention. It is a plane explanatory drawing similarly. It is a side explanatory view similarly. FIG. 6 is a perspective explanatory view for explaining the joining of the piezoelectric element member of the actuator and the FPC. It is the principal part expansion front explanatory drawing similarly. It is front explanatory drawing of 2nd Embodiment of the piezoelectric actuator of this invention. It is the typical block diagram seen from the side for demonstrating the structure of the wiring member joining apparatus which the piezoelectric element member of a piezoelectric actuator and FPC connect. It is front explanatory drawing of the actuator of a comparative example. It is a plane explanatory drawing similarly. It is the typical block diagram seen from the side for demonstrating the structure of an example of the wiring member joining apparatus which joins a comparative example. It is a principal part expansion explanatory drawing similarly. It is an isometric view explanatory drawing of an air suppression mechanism similarly. FIG. 3 is an explanatory perspective view of an external appearance of an embodiment of a liquid discharge head according to the present invention. FIG. 14 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber along the line AA in FIG. FIG. 3 is a cross-sectional explanatory view along the shorter direction of the liquid chamber (the direction in which the liquid chambers are arranged). 1 is a schematic configuration diagram of an entire mechanism unit of an example of an image forming apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator 2 ... Piezoelectric element member 3 ... FPC (flexible wiring board)
DESCRIPTION OF SYMBOLS 4 ... Base member 11 ... Piezoelectric element column 23a ... External electrode 31 ... Connection electrode 101 ... Flow path board 102 ... Vibration plate member 103 ... Nozzle plate 104 ... Nozzle 106 ... Pressurizing liquid chamber 110 ... Piezoelectric actuator 211k, 211c, 211m , 211y... Recording head (liquid ejection head)

Claims (4)

A plurality of piezoelectric element members formed with a plurality of piezoelectric element columns are arranged side by side along the column arrangement direction on the base member,
One flexible wiring board extending over the plurality of piezoelectric element members is directly connected to the plurality of piezoelectric element columns ,
In the tip portion of the flexible wiring board that is directly connected to the piezoelectric element column, a cut is formed corresponding to the position between the plurality of piezoelectric element members ,
Piezoelectric actuator height of the connecting surface to the piezoelectric element columns on both sides of the notch is characterized by different of Rukoto.   2. The piezoelectric actuator according to claim 1, wherein the shape of the cut is a wedge shape or a rectangular shape.   A liquid discharge head comprising the piezoelectric actuator according to claim 1.   An image forming apparatus comprising the liquid discharge head according to claim 3.

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