JP2008155620A - Piezoelectric actuator, liquid discharge head, liquid discharge device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low cost and reliable elongate actuator capable of connecting a plurality of energizing member without interfering by using piezoelectric element members of one kind by making one of the piezoelectric element columns in the end portion of the adjacent piezoelectric element members a driving piezoelectric element column and the other a not driving piezoelectric element column. <P>SOLUTION: The piezoelectric actuator includes the plurality of piezoelectric element members 2 and the plurality of energizing members 3 energizing each of the piezoelectric element members 2, the plurality of the piezoelectric element members 2 are connected and arranged lining the same in a line in a common base member 4, one end 3a of the energizing member 3 corresponding to the endmost driving piezoelectric element column 11A connected to the electrode 13 of the piezoelectric element member 2 is located in the outside from the outside end 11a of the driving piezoelectric element column 11A in a lining direction of the piezoelectric element columns 11, the other end 3b corresponding to the endmost not driving piezoelectric element column 11B not connected to the electrode 13 of the piezoelectric element member 2 is located in the inside from the outside end 11b of the not driving piezoelectric element column 11B and arranged so as not to overlap with the adjacent energizing member 3 each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  In general, as a printer / fax / copier or an image forming apparatus combining these functions, for example, a liquid ejection apparatus including a recording head composed of a liquid ejection head that ejects liquid droplets of a recording liquid (liquid) is used. While conveying a medium (hereinafter also referred to as “paper”, the material is not limited, and a recording medium, a recording medium, a transfer material, and recording paper are also used synonymously) In some cases, image formation (recording, printing, printing, and printing are also used synonymously) is made by adhering ink to a sheet.

  The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The term “not only” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium. Further, the liquid ejection apparatus means an apparatus that ejects liquid from a liquid ejection head, and is not limited to an apparatus that performs image formation.

  As the liquid discharge head, a piezoelectric element, particularly a stacked piezoelectric element in which piezoelectric layers and internal electrodes are alternately stacked, is used as pressure generating means (actuator means) for generating pressure to pressurize ink that is liquid in the liquid chamber. Then, a so-called piezoelectric actuator is used that deforms the elastically deformable diaphragm that forms the wall surface of the liquid chamber by the displacement of the laminated piezoelectric element in the direction d33 or d31, and changes the volume / pressure in the liquid chamber to discharge droplets. Known piezoelectric heads are known.

As a liquid discharge head using such a piezoelectric element, for example, Patent Document 1 describes a head in which an FPC having a narrower width than a piezoelectric element member is connected to a piezoelectric element member in which piezoelectric elements that are not driven at both ends are arranged. Yes.
JP-A-10-286951

Further, in Patent Document 2, the plurality of actuator units have a substantially trapezoidal shape, the parallel opposing sides of each actuator unit are along the longitudinal direction of the channel unit, and the oblique sides of the adjacent actuator units are channel units. The head is arranged in a staggered manner so as to overlap in the width direction of the cable, and the joint portion between the extension portion of the flat flexible cable and the flow path unit is disposed in a staggered manner along the longitudinal direction of the flow path unit. Is described.
JP 2006-168036 A

In Patent Document 3, a multilayered piezoelectric element serving as a driving unit and a multilayered piezoelectric element serving as a non-driving unit are alternately arranged, and a flexible printed cable is selectively and directly selected only on an end face electrode of the multilayered piezoelectric element serving as a driving unit. Is described.
JP-A-10-109410

Patent Document 4 describes a long head in which a plurality of piezoelectric element members in which a plurality of piezoelectric elements are formed by grooving are arranged on one base member along the arrangement direction of the plurality of piezoelectric elements. .
JP 2006-175845 A

Patent Document 5 describes a line head in which head cells including a plurality of piezoelectric elements are arranged on a base substrate.
JP 11-348279 A

Patent Document 6 discloses a common liquid chamber for storing ink, a plurality of pressure chambers communicating with the common liquid chamber, a pressure chamber block provided with a plurality of nozzles respectively communicating with each pressure chamber, a piezoelectric element, Inkjet including first and second electrodes for applying a voltage to the piezoelectric element, and a vibration plate, and an actuator arranged in the pressure chamber block so as to cover the pressure chamber of the pressure chamber block by the vibration plate The head is described.
JP 2002-225265 A

  As described above, high-speed printing is required for, for example, an inkjet recording apparatus as an image forming apparatus. In this case, there are means such as increasing the droplet ejection frequency and increasing the number of nozzles. However, if the droplet ejection frequency is increased, the carriage must be moved at a high speed accordingly, and a high-frequency motor that accurately controls a powerful motor is used. Therefore, it is necessary to solve the problem of stably ejecting droplets, so that it is necessary to lengthen a line head or the like that increases the number of nozzles by lengthening the head.

  Here, as described in Patent Document 4, a plurality of piezoelectric element members on which a plurality of piezoelectric elements are formed are arranged side by side to increase the length of the actuator or the head and drive the piezoelectric element column (driving piezoelectric element). In the case of adopting a configuration in which piezoelectric element columns that are not driven and non-driven piezoelectric element columns (non-driven piezoelectric element columns) are alternately arranged, a plurality of both end portions having non-driven piezoelectric element columns as described in Patent Document 1 If the piezoelectric element members are arranged side by side, the end portions of the adjacent piezoelectric element members become non-driven piezoelectric element columns at the joints of the piezoelectric element members, and the nozzle pitch will be different. Is required, which raises the problem of high costs.

  Further, when a plurality of piezoelectric element members are arranged side by side, if power is supplied by one power supply member to the drive piezoelectric element columns of all the piezoelectric element members, the positions of the electrodes of the power supply members and the drive piezoelectric element columns The problem that it becomes easy to produce the contact failure by shift | offset | difference arises. Therefore, when power is supplied by a plurality of power supply members, there arises a problem that the power supply members easily interfere with each other.

  Even when one power supply member is connected to one piezoelectric element member, the width in the same direction of the power supply member increases as the width of the piezoelectric element members in the arrangement direction increases, and the accumulation of dimensional tolerances increases. There is also a problem that the error due to the rise increases and the positional deviation between the electrode and the piezoelectric element column tends to occur.

  The present invention has been made in view of the above problems, and is a low-cost, high-reliability piezoelectric actuator that can be lengthened, a liquid discharge head including the piezoelectric actuator, a liquid discharge apparatus including the liquid discharge head, and an image. An object is to provide a forming apparatus.

  In order to solve the above problems, a piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in rows, A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column of the piezoelectric element member, and each power supply member is connected to a piezoelectric element column to which an electrode at one end of the piezoelectric element member is connected. The corresponding one end is located outside the outer end of the piezoelectric element column, and the other end corresponding to the endmost piezoelectric element column to which the electrode at the other end of the piezoelectric element member is not connected is from the outer end of the piezoelectric element column. It was set as the structure arrange | positioned in the state which is located inside and does not overlap with an adjacent electric power feeding member.

  The piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in rows, and one of at least two piezoelectric element members. A plurality of power supply members each having an electrode arranged corresponding to every other piezoelectric element column, and each power supply member is connected to the endmost piezoelectric element column to which the electrode at one end of the row of piezoelectric element members is connected. The corresponding one end is located outside the outer end of the piezoelectric element column, and the other end corresponding to the endmost piezoelectric element column to which the electrode at the other end of the row of piezoelectric element members is not connected is outside the piezoelectric element column. It was set as the structure arrange | positioned in the state which is located inside the edge and does not overlap with an adjacent electric power feeding member.

  In these piezoelectric actuators according to the present invention, it is preferable that the amount of deviation of one end of the power supply member with respect to the outer end of the piezoelectric element column at the extreme end is (1 pitch + 1 groove width) or less. In addition, it is preferable that the amount of deviation inward of the other end of the power feeding member with respect to the outer end of the piezoelectric element column at the extreme end is 1 pitch or less. Moreover, it is preferable that the pitch of the piezoelectric element columns to which the electrodes are connected is the same.

  The piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in a line, and every other piezoelectric element member. A plurality of power supply members having electrodes arranged corresponding to the element columns, and one end of the power supply member is located outside the outer end in the piezoelectric element column alignment direction of the piezoelectric element columns to which the electrodes are connected, The other end portion of the power supply member is positioned inside the outer end of the piezoelectric element columns in which the electrodes are not connected in the direction in which the piezoelectric element columns are arranged, and is arranged so as not to overlap the adjacent power supply members.

  The piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in rows, and every other piezoelectric element member. A plurality of power supply members having electrodes arranged corresponding to the piezoelectric element columns, and one end portion of the power supply member is positioned outside the outer end of the piezoelectric element columns in the direction in which the electrodes are connected. And the other end of the power supply member is positioned inside the outer end of the piezoelectric element column in which the electrodes are not connected and arranged in the piezoelectric element column arrangement direction, and is arranged so as not to overlap with the adjacent power supply member. did.

  The piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in a line, and every other piezoelectric element member. A plurality of power supply members having electrodes arranged corresponding to the element columns, and the width of one power supply member in the piezoelectric element column arrangement direction is narrower than the width of one piezoelectric element member in the same direction.

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

  The liquid discharge apparatus according to the present invention includes the liquid discharge head 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 of the present invention, a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in a line, and one of each piezoelectric element member A plurality of power supply members having electrodes arranged corresponding to the other piezoelectric element columns, and each power supply member has one end corresponding to the piezoelectric element column to which the electrode at one end of the piezoelectric element member is connected. The other end corresponding to the end of the piezoelectric element column, which is located outside the outer end of the element column and is not connected to the electrode at the other end of the piezoelectric element member, is located inside the outer end of the piezoelectric element column, Since it is arranged so that it does not overlap with the adjacent feeding member, one of the piezoelectric element columns at the end of the adjacent piezoelectric element member is a driven piezoelectric element column, and the other is a non-driven piezoelectric element column. Therefore, one type of piezoelectric element member is used. Bets can be, and can be connected without interfering the plurality of power supply member, it is possible to obtain a high long actuator reliability at low cost.

  According to the piezoelectric actuator according to the present invention, an even number of piezoelectric element columns are formed at a predetermined pitch through grooves, and a plurality of piezoelectric element members arranged in a line and at least two piezoelectric element members are arranged. A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column, and each power supply member is an endmost piezoelectric element to which an electrode at one end of a row of piezoelectric element members is connected One end corresponding to the column is located outside the outer end of the piezoelectric element column, and the other end corresponding to the endmost piezoelectric element column to which the electrode at the other end of the row of piezoelectric element members is not connected is the piezoelectric element column. Since one of the piezoelectric element columns at the end portion of the adjacent piezoelectric element member is driven, the piezoelectric element column is driven so as to be disposed inside the outer end of the piezoelectric element member so as not to overlap with the adjacent feeding member. The other is a non-driven piezoelectric element column Conductive type of element member can be a single type, and can be connected without interfering the plurality of power supply member, it is possible to obtain a high long actuator reliability at low cost.

  According to the piezoelectric actuator of the present invention, a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in rows, and every other piezoelectric element member is arranged. A plurality of power supply members having electrodes arranged corresponding to the piezoelectric element columns, and one end portion of the power supply member is positioned outside the outer end of the piezoelectric element columns in the direction in which the electrodes are connected. And the other end of the power supply member is positioned inside the outer end of the piezoelectric element column in which the electrodes are not connected and arranged in the piezoelectric element column arrangement direction, and is arranged so as not to overlap with the adjacent power supply member. Therefore, one of the piezoelectric element columns at the end of the adjacent piezoelectric element members is a driven piezoelectric element column, and the other is a non-driven piezoelectric element column. Interfering with the power supply member Able to Ku connection, it is possible to obtain a high long actuator reliability at low cost.

  The piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in rows, and every other piezoelectric element member. A plurality of power supply members having electrodes arranged corresponding to the piezoelectric element columns, and one end portion of the power supply member is positioned outside the outer end of the piezoelectric element columns in the direction in which the electrodes are connected. And the other end of the power supply member is positioned inside the outer end of the piezoelectric element column in which the electrodes are not connected and arranged in the piezoelectric element column arrangement direction, and is arranged so as not to overlap with the adjacent power supply member. Therefore, one of the piezoelectric element columns at the end of the adjacent piezoelectric element members is a driven piezoelectric element column, and the other is a non-driven piezoelectric element column. Interfering with the power supply member Able to Ku connection, it is possible to obtain a high long actuator reliability at low cost.

  The piezoelectric actuator according to the present invention includes a plurality of piezoelectric element members in which an even number of piezoelectric element columns are formed at predetermined pitches through grooves and arranged in a line, and every other piezoelectric element member. A plurality of power supply members having electrodes arranged corresponding to the element columns, and the width of one power supply member in the piezoelectric element column arrangement direction is narrower than the width of one piezoelectric element member in the same direction. The piezoelectric element member can be of one type, and a plurality of power supply members can be connected without interfering with each other, and a long actuator with low cost and high reliability can be obtained.

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

  According to the liquid discharge apparatus according to the present invention, since the liquid discharge head according to the present invention is provided, the cost can be reduced.

  Since the image forming apparatus according to the present invention includes the liquid ejection head according to the present invention, high-speed recording can be achieved at low cost.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of a piezoelectric actuator according to the present invention will be described with reference to FIGS. 1 is a schematic explanatory view of the piezoelectric actuator, and FIG. 2 is an enlarged explanatory view of a main part of the piezoelectric actuator. In addition, the power feeding member is shown in a transmissive state except for the electrodes for the sake of clarity (the same applies to the following embodiments).

  The piezoelectric actuator 1 includes a plurality of piezoelectric element members 2 and a plurality of power supply members 3 composed of FPC or the like for supplying power to each piezoelectric element member 2. The plurality of piezoelectric element members 2 are a common base member. 4 are arranged in a row and joined.

  The piezoelectric element member 2 is formed with an even number of piezoelectric element columns 11 at a predetermined pitch Pn via slit grooves 12 having a groove width Sn by performing slit processing (groove processing) without being divided. ing. As shown in FIG. 3, the pitch between the piezoelectric element columns 11 of the two adjacent piezoelectric element members 2 is also defined as the groove width Sn, and the pitch between the piezoelectric element columns 11 of the two adjacent piezoelectric element members 2 is also a pitch. Pn, and all the piezoelectric element columns 11 are arranged at the same pitch Pn.

Each piezoelectric element column 11 of the piezoelectric element member 2 is used as a piezoelectric element column (driving piezoelectric element column) 11A that is driven every other one and a piezoelectric element column (non-driving piezoelectric element column) 11B that is not driven. Thus, by arranging the number of piezoelectric element columns 11 of the piezoelectric element member 2 to be an even number, when arranging a plurality of piezoelectric element members 2, the piezoelectric element columns 11 at the ends of one of the adjacent piezoelectric element members 2 are arranged. The piezoelectric element column 11 at the end of the other piezoelectric element member 2 has a non-driving piezoelectric element column 11B relationship with the driving piezoelectric element column 11A.

  The power supply member 3 has electrodes 13 arranged corresponding to every other piezoelectric element column 11 of the piezoelectric element member 2. The piezoelectric element column 11 corresponding to the electrode 13 becomes the driving piezoelectric element column 11A.

  In the power supply member 3, one end 3a corresponding to the drive piezoelectric element column 11A at the extreme end to which the electrode 13 is connected is positioned outside the outer end 11a of the drive piezoelectric element column 11A in the direction in which the piezoelectric element columns 11 are arranged. The other end 3b corresponding to the endmost non-driving piezoelectric element column 11B to which the electrode 13 is not connected is positioned inside the outer end 11b of the non-driving piezoelectric element column 11B and overlaps with the adjacent power feeding member 3. It is arranged in a state that does not become.

  Here, as shown in FIG. 4, the shift amount X1 of the feeding member 3 to the outside of the one end 3a with respect to the outer end 11a of the drive piezoelectric element column 11A at the end is not more than (1 pitch + 1 groove width), that is, X ≦ (Pn + S1). Further, as shown in FIG. 5, the shift amount X2 to the inside of the other end 3b of the power supply member 3 with respect to the outer end 11b of the endmost non-driving piezoelectric element column 11B is 1 pitch or less, that is, X2 ≦ Pn. Yes. Thereby, the outer dimensional tolerance of the power feeding member 3 can be increased.

  With this configuration, the piezoelectric element member 2 has an even number of piezoelectric element columns 11, so that one of the piezoelectric element columns 11 at the end of the adjacent piezoelectric element member 2 is the driving piezoelectric element column 11A and the other is the driving piezoelectric element column 11A. It becomes the non-driving piezoelectric element column 11B, and it becomes possible to arrange the driving piezoelectric element columns 11A and the non-piezoelectric element columns 11B alternately by arranging one kind of piezoelectric element member 2, thereby reducing the cost. it can.

  Further, since power is supplied to the drive piezoelectric element column 11A of each piezoelectric element member 2 by the plurality of power supply members 3, there is little misalignment between the electrode 13 of the power supply member 3 and the drive piezoelectric element column 11A of the piezoelectric element member 2, and the contact Defects are reduced. At the same time, one end of the power feeding member 3 is located outside the outer end of the driving piezoelectric element 11A, and the other end is located inside the outer end of the non-driving piezoelectric element 11B. Interference is prevented. Thereby, reliability is improved.

  Specifically, a piezoelectric element member (PZT unit) 2 having a piezoelectric element column (PZT column) 11 made of an even number of PZTs is fixed on a metal base member 4 having a length of about 300 mm, and the PZT unit is fixed. Two PZT pillars 11 were connected to every other electrode 13 of the power feeding member 3. Here, the width of the PZT column 11 is about 50 μm, and the pitch P1 of the PZT column 11 is about 80 μm (the groove width S1 is about 30 μm). The power supply member 3 was FPC (Flexible Printed Circuit Board), and the PZT column 11 and the electrode 13 were connected by solder joint.

  In this way, an even number of piezoelectric element columns are formed at predetermined pitches through the grooves, and are arranged in a plurality of piezoelectric element members arranged in rows and every other piezoelectric element column of each piezoelectric element member. A plurality of power supply members having correspondingly arranged electrodes, and each power supply member has one end corresponding to the piezoelectric element column to which the electrode at one end of the piezoelectric element member is connected from the outer end of the piezoelectric element column. The other end corresponding to the end of the piezoelectric element column that is located outside and not connected to the electrode at the other end of the piezoelectric element member is positioned inside the outer end of the piezoelectric element column, and is adjacent to the adjacent feeding member. With the configuration in which the piezoelectric element members are arranged so as not to overlap each other, one of the piezoelectric element columns at the end of the adjacent piezoelectric element member becomes a driven piezoelectric element column, and the other becomes a non-driven piezoelectric element column. One type can be used, and multiple power supply members And can be connected without interference, it is possible to obtain a high long actuator reliability at low cost.

  Further, an even number of piezoelectric element columns are formed at a predetermined pitch through grooves, and correspond to a plurality of piezoelectric element members arranged in a line and every other piezoelectric element column of the piezoelectric element members. A plurality of power supply members having electrodes arranged, and one end portion of the power supply member is located outside the outer end of the piezoelectric element column to which the electrodes are connected in the direction in which the piezoelectric element columns are arranged, and the other end portion of the power supply member Is located inside the outer end of the piezoelectric element columns in which the electrodes are not connected in the direction in which the piezoelectric element columns are arranged, and is arranged so as not to overlap with the adjacent power supply member. One of the piezoelectric element columns at the end of the member is a driven piezoelectric element column, and the other is a non-driven piezoelectric element column, so that one type of piezoelectric element member can be used without interfering with a plurality of power feeding members. Can be connected, low cost In it is possible to obtain a highly reliable long actuator.

Next, a second embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIG. FIG. 6 is an enlarged explanatory view of a main part of the piezoelectric actuator.
Here, the base member on which the plurality of piezoelectric element members 2 are arranged is divided into a plurality of base members 14, and each base member 14 has a predetermined width (same as the groove width S <b> 1) between the adjacent base members 14. The spacers 5 are preferably arranged side by side.

  According to this configuration, when a problem occurs in the manufacturing process due to slit groove processing or the like in one piezoelectric element member 12, it is sufficient to replace only the piezoelectric element member 12 together with the base member 14.

Next, a third embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. FIG. 7 is a schematic explanatory view of the piezoelectric actuator, and FIG. 8 is an enlarged explanatory view of a main part of the piezoelectric actuator.
Here, one power supply member 23 is shared by the two piezoelectric element members 2 and 2. In this case, the power supply member 23 is driven in the direction in which the piezoelectric element columns 11 are arranged at the one end 3a corresponding to the drive piezoelectric element column 11A at the end of the two piezoelectric element members 2 to which the electrode 13 is connected. The other end 3b corresponding to the most non-driven piezoelectric element column 11B in the state where the two piezoelectric element members 2 to which the electrode 13 is not connected is located outside the outer end 11a of the piezoelectric element column 11A is the non-driven piezoelectric element. It is located inside the outer end 11b of the element column 11B, and is arranged in a state where it does not overlap with the adjacent power feeding member 3.

  As described above, by configuring one power supply member to be connected to two or more piezoelectric element members, the effects described in the first embodiment can be obtained, and the number of parts of the power supply member can be reduced. can do. Here, power is supplied to two piezoelectric element members with one power supply member. However, if a plurality of power supply members are used, power is supplied to three or more piezoelectric element members with one power supply member. It is also possible.

Next, a third embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIGS. FIG. 9 is a schematic explanatory view of the piezoelectric actuator, and FIG. 10 is an enlarged explanatory view of a main part of the piezoelectric actuator.
Here, a plurality (two in this example) of power supply members 23 and 23 are connected to one piezoelectric element member 2 in association with each other. Here, one end of one power supply member 23 is positioned outside the outer end in the piezoelectric element column arrangement direction of the drive piezoelectric element column 11A to which the electrode 13 is connected, and the electrode 13 is connected to the other end of the power supply member 23. The non-driving piezoelectric element column 11B that is not connected is located inside the outer end in the direction in which the piezoelectric element columns are arranged, and is disposed so as not to overlap with the adjacent feeding member 23.

  In other words, the pitch of the piezoelectric element columns 11 is determined by the processing accuracy of a slit (groove) processing device (for example, a dicer), and an accuracy of, for example, ± 3 μm per 500 mm length can be ensured. On the other hand, as for the arrangement pitch of the electrodes 13 of the power supply member 23, the cumulative pitch tolerance increases as the width of the power supply member 23 in the piezoelectric element column arrangement direction becomes longer. Therefore, when the length of one piezoelectric element member 2 is increased, when one power supply member 23 is connected to one or a plurality of piezoelectric element members 2, the arrangement pitch of the electrodes 13 and the driving piezoelectric element column 11A There is a possibility that a connection error may occur due to a large deviation from the arrangement pitch. Therefore, such a problem can be avoided by connecting a plurality of power feeding members to one piezoelectric element member.

  In this way, an even number of piezoelectric element columns are formed at a predetermined pitch through the grooves, and a plurality of piezoelectric element members arranged in a row and every other piezoelectric element column of one piezoelectric element member are arranged. A plurality of power supply members each having an electrode disposed corresponding to the first power supply member, wherein one end of the power supply member is positioned outside the outer end of the piezoelectric element column in the direction in which the piezoelectric element columns are connected, The other end of the piezoelectric element column is not connected to the electrode, and is located inside the outer end in the piezoelectric element column alignment direction, and is arranged in a state where it does not overlap with the adjacent feeding member, One of the piezoelectric element columns at the end of the adjacent piezoelectric element member is a driven piezoelectric element column, and the other is a non-driven piezoelectric element column, so that one type of piezoelectric element member can be used. It can be connected without interference Te, it is possible to obtain a high long actuator reliability at low cost.

Next, a fourth embodiment of the piezoelectric actuator according to the present invention will be described with reference to FIG. FIG. 11 is an enlarged explanatory view of the main part of the piezoelectric actuator.
Here, the width L2 of one power supply member 23 in the direction in which the piezoelectric element columns are arranged is narrower than the width L1 of one piezoelectric element member 2 in the same direction. As a result, it is possible to arrange the adjacent two power supply members 23 so as not to overlap with each other, and it is not required to have high accuracy as the positional accuracy of the two power supply members 23, 23, thereby improving the connection workability of the power supply members 23. To do.

  In this way, an even number of piezoelectric element columns are formed at a predetermined pitch through grooves, and correspond to a plurality of piezoelectric element members arranged in a row and every other piezoelectric element column of the piezoelectric element members. A plurality of power supply members each having an electrode disposed in a manner such that the width of one power supply member in the direction of arranging piezoelectric element columns is narrower than the width of one piezoelectric element member in the same direction. One type of member can be used, a plurality of power supply members can be connected without interfering with each other, and a long actuator with low cost and high reliability can be obtained.

  In this case, a configuration in which one power supply member is connected across a plurality of piezoelectric element members, a configuration in which a plurality of power supply members are connected to one piezoelectric element member, and the like can also be employed.

  Next, an embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 12 is a perspective explanatory view of the appearance of the liquid discharge head, FIG. 13 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber along the line AA in FIG. FIG. 5 is an explanatory cross-sectional view along the liquid chamber short direction (direction in which the liquid chambers are arranged).

  The liquid discharge head includes a flow path substrate (liquid chamber substrate) 101 formed of a SUS substrate, a vibration plate member 102 bonded to the lower surface of the flow path substrate 1, and a nozzle plate 103 bonded to the upper surface of the flow path substrate 101. And a liquid chamber (hereinafter referred to as a “pressurized liquid chamber” as a separate flow path) through which a nozzle 104 that discharges droplets (liquid droplets) communicates with each other. 106, a fluid resistance unit 107 that also serves as a supply path for supplying ink (recording liquid) 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 surface 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 plurality of power supply members 113 configured by an FPC or the like that supplies power to each piezoelectric element member 112. 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 between the piezoelectric element columns 111 of the piezoelectric element member 112 is also set 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 power supply member 113 is made of FPC and has electrodes (not shown) arranged corresponding to every other drive piezoelectric element column 111A of the piezoelectric element member 112. The power supply member 113 has one end corresponding to the drive piezoelectric element column 111A at the extreme end to which the electrode is connected positioned outside the outer end of the drive piezoelectric element column 111A in the arrangement direction of the piezoelectric element columns 111. The other end corresponding to the endmost non-driving piezoelectric element column 111B that is not connected is positioned inside the outer end of the non-driving piezoelectric element column 111B and arranged so as not to overlap with the adjacent feeding member 113. Yes.

  The driving piezoelectric element column 111A of the piezoelectric actuator 110 is 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. It is joined.

  The piezoelectric element member 112 is composed of a lead zirconate titanate (PZT) piezoelectric layer having a thickness of 10 to 50 μm / layer, and an internal electrode layer made of silver and palladium (AgPd) having a thickness of several μm / layer. 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.

  The base member 114 is preferably formed of a metal material. If the material (material) of the base member 114 is a metal, heat storage due to self-heating of the piezoelectric element member 112 can be prevented. Further, when the linear expansion coefficient of the base member 114 is large, the adhesive may be peeled off at the bonding interface between the base member 114 and the piezoelectric element member 112 at a high temperature or a low temperature. That is, when the total length of the piezoelectric element is not long, there was almost no problem of peeling between the piezoelectric element and the base member due to a temperature difference due to environmental fluctuations, but when there are about 400 nozzles at 300 dpi per piezoelectric element, When the length per one became 30-40 mm or more, this problem became remarkable. Therefore, it is preferable to use a material having a linear expansion coefficient of 10E-6 / ° C. or less as the material of the base member 13. In particular, it has been confirmed that if all the parts having thermal expansion coefficients of 10E-6 / ° C. or less are bonded and bonded to the piezoelectric element member 112, it is very effective against peeling of the bonding interface. As a specific example, it is possible to arrange the material with a stainless steel plate.

  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 addition, as described above, since this liquid discharge head is made of SUS and has the same thermal expansion coefficient, various problems due to thermal expansion during the assembly or use of the head are avoided. Can do.

  In the liquid discharge head configured in this way, 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 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.

  As described above, since the liquid discharge head includes the piezoelectric actuator according to the present invention, it can be a low-cost and highly reliable head.

Next, an example of the image forming apparatus according to the present invention including the liquid ejection apparatus according to the present invention will be described with reference to FIG. FIG. 15 is a schematic configuration diagram of the entire mechanism unit of the apparatus.
The image forming apparatus includes an image forming unit 202 and the like inside the apparatus main body 201, and includes a paper feed tray 204 on the lower side of the apparatus main body 201 on which a large number of recording media (sheets) 203 can be stacked. The paper 203 fed from the paper tray 204 is taken in, a required image is recorded by the image forming unit 202 while the paper 203 is transported by the transport mechanism 205, and then a paper discharge tray 206 mounted on the side of the apparatus main body 201. The sheet 203 is discharged.

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

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

  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 embodiment, the liquid ejection apparatus according to the present invention has been described as an example applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this. For example, an image forming apparatus such as a printer / fax / copier multifunction machine is used. Can be applied to. 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.

It is a typical explanatory view of a 1st embodiment of a piezoelectric actuator concerning the present invention. It is a principal part expansion explanatory drawing similarly. It is a typical explanatory view similarly used for description of a piezoelectric element member. It is explanatory drawing with which it uses for description of the deviation | shift amount of the piezoelectric element column outer end of a piezoelectric element member, and the end of an electric power feeding member. It is explanatory drawing with which it uses for description of the deviation | shift amount of the piezoelectric element column outer end of a piezoelectric element member, and the other end of an electric power feeding member. It is principal part expansion explanatory drawing of 2nd Embodiment of the piezoelectric actuator which concerns on this invention. It is a typical explanatory view of a 3rd embodiment of a piezoelectric actuator concerning the present invention. It is a principal part expansion explanatory drawing similarly. It is typical explanatory drawing of 4th Embodiment of the piezoelectric actuator which concerns on this invention. It is a principal part expansion explanatory drawing similarly. It is principal part expansion explanatory drawing of 5th Embodiment of the piezoelectric actuator which concerns on this invention. FIG. 2 is an external perspective view illustrating an example of a liquid discharge head according to the present invention. FIG. 13 is an explanatory cross-sectional view along the liquid chamber longitudinal direction (a direction orthogonal to the liquid chamber arrangement direction) along the line AA in FIG. 12. FIG. 6 is a cross-sectional explanatory view along the liquid chamber short direction (liquid chamber arrangement direction). 1 is an overall configuration explanatory view showing an example of an image forming apparatus according to the present invention including a liquid ejection apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator 2 ... Piezoelectric element member 3 ... Feeding member 4 ... Base member 11 ... Piezoelectric element column 11A ... Drive piezoelectric element column 11B ... Non-drive piezoelectric element column 12 ... Slit groove 13 ... Electrode 101 ... Channel substrate 102 ... Vibration Plate member 103 ... Nozzle plate 104 ... Nozzle 106 ... Pressurized liquid chamber 110 ... Piezoelectric actuator 211k, 211c, 211m, 211y ... Recording head (liquid ejection head)

Claims (11)

A plurality of piezoelectric element members, each having an even number of piezoelectric element columns formed at a predetermined pitch through grooves and arranged in a line;
A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column of each piezoelectric element member;
Each power supply member has one end corresponding to the piezoelectric element column to which the electrode at one end of the piezoelectric element member is connected positioned outside the outer end of the piezoelectric element column, and the other end of the piezoelectric element member The other end corresponding to the endmost piezoelectric element column to which no electrode is connected is located inside the outer end of the piezoelectric element column, and is arranged in a state where it does not overlap with the adjacent feeding member. A piezoelectric actuator. A plurality of piezoelectric element members, each having an even number of piezoelectric element columns formed at a predetermined pitch through grooves and arranged in a line;
A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column of at least two piezoelectric element members;
Each feeding member has one end corresponding to the endmost piezoelectric element column to which the electrode at one end of the row of the piezoelectric element members is connected positioned outside the outer end of the piezoelectric element column, and the piezoelectric element member The other end corresponding to the endmost piezoelectric element column to which the electrode at the other end of the row is not connected is located on the inner side from the outer end of the piezoelectric element column and does not overlap with the adjacent feeding member A piezoelectric actuator characterized by being arranged in the above.   3. The piezoelectric actuator according to claim 1, wherein an amount of deviation of one end of the power feeding member with respect to an outer end of the endmost piezoelectric element column is equal to or less than (1 pitch + 1 groove width). Piezoelectric actuator.   4. The piezoelectric actuator according to claim 1, wherein an amount of deviation of the outermost end of the piezoelectric element column toward the inner side of the other end of the power supply member is one pitch or less. Piezoelectric actuator.   5. The piezoelectric actuator according to claim 1, wherein the pitches of the piezoelectric element columns to which the electrodes are connected are the same. A plurality of piezoelectric element members, each having an even number of piezoelectric element columns formed at a predetermined pitch through grooves and arranged in a line;
A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column of the piezoelectric element member;
One end portion of the power supply member is located outside the outer end of the piezoelectric element column to which the electrode is connected in the direction in which the piezoelectric element columns are arranged, and the other end portion of the power supply member is the piezoelectric device to which the electrode is not connected. A piezoelectric actuator, wherein the piezoelectric element is located inside an outer end of the element column in the direction in which the piezoelectric element columns are arranged, and is arranged so as not to overlap with the adjacent feeding member. A plurality of piezoelectric element members, each having an even number of piezoelectric element columns formed at a predetermined pitch through grooves and arranged in a line;
A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column of the one piezoelectric element member;
One end portion of the power supply member is located outside the outer end of the piezoelectric element column to which the electrode is connected in the direction in which the piezoelectric element columns are arranged, and the other end portion of the power supply member is the piezoelectric device to which the electrode is not connected. A piezoelectric actuator, wherein the piezoelectric element is located inside an outer end of the element column in the direction in which the piezoelectric element columns are arranged, and is arranged so as not to overlap with the adjacent feeding member. A plurality of piezoelectric element members, each having an even number of piezoelectric element columns formed at a predetermined pitch through grooves and arranged in a line;
A plurality of power supply members having electrodes arranged corresponding to every other piezoelectric element column of the piezoelectric element member;
A piezoelectric actuator characterized in that a width of one power feeding member in the direction of arranging piezoelectric element columns is narrower than a width of one piezoelectric element member in the same direction.   A liquid discharge head that discharges liquid droplets from the nozzles by displacing a diaphragm that forms a wall surface of a liquid chamber that communicates with a nozzle that discharges liquid droplets with the piezoelectric actuator. A liquid discharge head, which is the piezoelectric actuator according to any one of the above.   A liquid discharge apparatus comprising a liquid discharge head for discharging droplets, wherein the liquid discharge head is the liquid discharge head according to claim 9.   An image forming apparatus comprising a liquid discharge head for discharging liquid droplets to form an image, wherein the liquid discharge head is the liquid discharge head according to claim 9.

Images