JP2011056731A - Method for manufacturing piezoelectric actuator, piezoelectric actuator, liquid delivering head, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a first piezoelectric element pillar particularly is liable to fall down when high density is attempted when a plurality of piezoelectric element pillars are formed by applying channel processing to a piezoelectric member. <P>SOLUTION: The piezoelectric member 1 joined to a base member 8 has a region 1C where internal electrodes 3A and 3B are not present, and the channel processing is started from a region 1C where the internal electrodes 3A and 3B are not present to form a first channel 10a, and while a blade 9 is moved in one direction, the channel 10 is successively processed by an equal pitch to form a plurality of the piezoelectric element pillars 11 by the equal pitch. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. As an apparatus, an ink jet recording apparatus or the like is known. This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

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

  Conventionally, a piezoelectric element as a pressure generating means (actuator means) for generating pressure to pressurize ink that is liquid in a pressure chamber (also referred to as a liquid chamber, an individual liquid chamber, or a pressurizing chamber) as a liquid ejection head In particular, elastic deformation in which a plurality of piezoelectric element columns are formed using a laminated piezoelectric member in which piezoelectric layers and internal electrodes are alternately stacked, and a wall surface of a liquid chamber is formed by displacement of the piezoelectric element columns in the d33 or d31 direction. There is known a piezoelectric head using a so-called piezoelectric actuator that deforms a possible diaphragm and changes a volume in a pressure chamber to discharge a droplet. In this specification, “piezoelectric element” is used as a general term for electromechanical transducer elements.

  As a conventional piezoelectric actuator, for example, a region where an internal electrode does not exist is provided on both sides in the arrangement direction of piezoelectric vibrators (corresponding to columns), the region is formed in a region where the internal electrode does not exist, and is separated by a slit Some include a dummy piezoelectric vibrator including a broken piece in which no internal electrode exists, a region in which the internal electrode exists, and a region in which no internal electrode exists (Patent Document 1).

  Similarly, a piezoelectric actuator having a piezoelectric element column having no internal electrode is also known (Patent Documents 2 and 3).

Japanese Patent No. 3452133 Japanese Patent No. 3381669 JP 2000-177130 A

  By the way, the groove processing for the laminated piezoelectric member is performed by a dicing saw or a wire saw. However, since the displacement amount of the piezoelectric element column can be obtained as the number of layers increases, the groove processing for the piezoelectric member having a larger number of layers is achieved. Then it is necessary to cut deeply. In addition, in order to provide a liquid discharge head using a piezoelectric actuator and perform high image quality and high-speed printing, the nozzle density must be increased, and as a result, the piezoelectric element column density of the piezoelectric actuator is also increased. (It is necessary to grooving at a fine pitch.)

  However, if the piezoelectric element is deeply cut and grooved with a fine pitch, the piezoelectric element columns formed by the grooving become elongated and columnar, so the starting point is the interface between the piezoelectric layer (piezoelectric material) and the internal electrode. There is a problem that so-called column collapse tends to occur.

  Further, when the piezoelectric element columns are processed at an equal pitch, the first processed groove does not have a stress relief field during processing, and therefore the piezoelectric element columns in the vicinity of the blade as the processing means receive a lot of damage. As a result, in the next pitch processing, the damaged part becomes a pillar, and there is a problem that the column collapse is likely to occur. Since the second and subsequent piezoelectric element columns are grooved with the grooves already processed immediately before, the stress in the column collapse direction is easily released during processing, and column collapse hardly occurs.

  In this case, in order to prevent the occurrence of the first column collapse, it is effective to widen the column width or reduce the groove depth. In this case, however, the channel using the first column is used in the head structure. Only the droplet discharge characteristics are different from those of other channels, so that variations in droplet discharge characteristics between channels (between nozzles) occur. Moreover, even if the column width is widened by using the first one as a non-driving part, it is necessary to make the length of the piezoelectric member extra long, which increases the cost.

  The present invention has been made in view of the above problems, and an object thereof is to reduce the column collapse of a piezoelectric element column.

In order to solve the above problems, a method for manufacturing a piezoelectric actuator according to the present invention includes:
Manufacture of a piezoelectric actuator in which a plurality of pillars are formed by performing groove processing in order from the end on a laminated piezoelectric member in which a piezoelectric material and internal electrodes are laminated, and at least a part of the plurality of pillars can be deformed In the method
The plurality of pillars have a region processed at an equal pitch,
The grooving of the region processed at the equal pitch is configured such that the grooving is started from a region where the internal electrode does not exist, and the grooving of the equal pitch is performed in one direction.

  Here, the last groove processing of the region processed at the equal pitch may be performed in the region where the internal electrode exists.

  Moreover, it can be set as the groove | channel process using a dicing saw.

  The piezoelectric actuator according to the present invention is manufactured by the method for manufacturing a piezoelectric actuator according to the present invention.

The piezoelectric actuator according to the present invention is
In the piezoelectric actuator in which a plurality of pillars are formed by performing groove processing in order from the end on a laminated piezoelectric member in which a piezoelectric material and internal electrodes are laminated, and at least a part of the plurality of pillars is deformable.
The internal electrode is not exposed on at least one side surface of a column formed first in a region processed at an equal pitch.

The piezoelectric actuator according to the present invention is
In the piezoelectric actuator in which a plurality of pillars are formed by performing groove processing in order from the end on a laminated piezoelectric member in which a piezoelectric material and internal electrodes are laminated, and at least a part of the plurality of pillars is deformable.
The number of internal electrodes exposed on at least one side surface of the column formed first in a region processed at an equal pitch is equal to the number of internal electrodes exposed on the side surface of the column located in the center. Less configuration.

  Here, the internal electrode exposed on at least one side surface of the column formed first is the inner side of the column base side compared to the internal electrode exposed on the side surface of the column located in the center. A configuration with few electrodes is possible.

  In the piezoelectric actuator according to the present invention, the aspect ratio of the pillars in the region processed at an equal pitch can be 15 or more.

  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 method for manufacturing a piezoelectric actuator according to the present invention, a plurality of pillars have a region processed at an equal pitch, and the groove processing of the region processed at an equal pitch is performed from the region where no internal electrode exists. Since the groove is formed at an equal pitch in one direction, the column collapse of the piezoelectric element column can be reduced.

  Since the piezoelectric actuator according to the present invention is manufactured by the method for manufacturing a piezoelectric actuator according to the present invention, the column collapse of the piezoelectric element column is reduced, and highly reliable operation characteristics can be obtained.

  According to the piezoelectric actuator of the present invention, the internal electrode is not exposed on at least one side surface of the first column formed in the region processed at an equal pitch. Falling is reduced and highly reliable operating characteristics can be obtained.

  According to the piezoelectric actuator according to the present invention, the number of internal electrodes exposed on at least one side surface of a column formed first in a region processed at an equal pitch is equal to that of the column located at the center. Since the configuration is smaller than the number of internal electrodes exposed on the side surfaces, the column collapse of the piezoelectric element column is reduced, and highly reliable operation characteristics can be obtained.

  Since the liquid discharge head according to the present invention includes the piezoelectric actuator according to the present invention, it can be a high-density nozzle.

  Since the image forming apparatus according to the present invention includes the liquid discharge head according to the present invention, a high-quality image can be formed.

It is a front explanatory view of the piezoelectric member before grooving used for explanation of the piezoelectric actuator concerning the 1st embodiment of the present invention, and its manufacturing method. (A) is sectional explanatory drawing which follows the AA line of FIG. 1, (b) is sectional explanatory drawing which follows the BB line of FIG. 1, (c) is sectional explanatory drawing which follows the CC line of FIG. It is. It is principal part front explanatory drawing explaining a groove processing process. It is principal part front explanatory drawing with which it uses for description of the piezoelectric member and groove processing process of a comparative example. It is principal part front explanatory drawing of the piezoelectric actuator which concerns on 2nd Embodiment of this invention. It is principal part front explanatory drawing with which it uses for description of the connection of the wiring member with respect to the piezoelectric actuator which concerns on 1st Embodiment. It is a principal part front explanatory drawing similarly used for description of the state which the connection position of the wiring member shifted | deviated. It is front explanatory drawing of the piezoelectric actuator which concerns on 3rd Embodiment of this invention. It is principal part front explanatory drawing of the piezoelectric actuator which concerns on 4th Embodiment of this invention. It is principal part front explanatory drawing of the piezoelectric actuator which concerns on an example of 5th Embodiment of this invention. It is principal part front explanatory drawing of the piezoelectric actuator which concerns on the other example of the same embodiment. It is typical explanatory drawing with which it uses for description of a groove processing means. It is principal part front explanatory drawing with which it uses for description of an aspect ratio. FIG. 4 is an explanatory cross-sectional view along a direction orthogonal to a nozzle arrangement direction showing an example of a liquid discharge head according to the present invention. It is a principal part sectional view similarly along a nozzle arrangement direction. 1 is an overall configuration diagram illustrating an example of an image forming apparatus according to the present invention. Similarly it is principal part plane explanatory drawing. It is a whole block diagram which shows the other example of the image forming apparatus which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A piezoelectric actuator and a manufacturing method thereof according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a front explanatory view of the piezoelectric member before the groove processing, FIG. 2A is a cross-sectional explanatory view taken along line AA in FIG. 1, and FIG. 1B is a cross-sectional explanatory view taken along line BB in FIG. FIG. 3C is a cross-sectional explanatory view taken along the line C-C in FIG. 1, and FIG. 3 is a main part front explanatory view for explaining a groove processing step.

  First, a description will be given with reference to FIGS. The piezoelectric member 1 is made of, for example, a piezoelectric zirconate titanate (PZT) piezoelectric layer (piezoelectric material layer) 2 having a thickness of 10 to 50 μm / layer and a silver / palladium (AgPd) layer having a thickness of several μm / layer. The internal electrodes 3A and 3B are alternately stacked. Then, in the longitudinal direction of the piezoelectric member 1, in the central region 1A, the internal electrodes 3A, 3B are alternately drawn out to the end face and connected to the individual electrode 4 and the first common electrode 5A, which are end face electrodes (external electrodes), respectively. Yes. In the end regions 1B1 and 1B2, the second common electrode 5B and the first common electrode 5B, which are end surface electrodes (external electrodes) formed on the same end surface as the individual electrode 4 by drawing out the internal electrodes 3A and 3B to both end surfaces, respectively. It is connected to the electrode 5A. Further, a region consisting only of the piezoelectric layer 2 where the internal electrodes 3A and 3B are not formed is provided between the central region 1A and the one end region 1B1. The piezoelectric member 1 is joined to the base member 8. In FIG. 1, the external electrodes are not shown.

  When a groove is formed on the piezoelectric member 1 to form a piezoelectric element column that is a column of the present invention, as shown in FIG. 3A, the region 1C without the internal electrodes 3A and 3B of the piezoelectric member 1 is formed. As a first groove processing position, a groove processing means such as a blade 9 of a dicing saw is used, and the first groove 10 (however, the first groove is formed with respect to the piezoelectric member 1 as shown in FIG. 3B). Is then moved to a predetermined pitch in one direction (arrow direction) of the dicing blade 9 to form the second groove 10 to form the first piezoelectric element column 11 (however, The first column is denoted as “11a”). Similarly, by moving the dicing blade 9 in one direction at equal pitches and grooving repeatedly, the second and subsequent grooves 10 are formed at equal pitches. Process with.

  As described above, the position where the first groove 10a is formed is the region 1C where the internal electrodes 3A and 3B are not provided, thereby preventing the first pillar 11a formed by the processing of the second groove 10 from collapsing. Can do. This is because column collapse occurs from the interface between the piezoelectric layer 2 and the internal electrodes 3A and 3B. The first pillar 11a does not have the internal electrodes 3A and 3B on the side surface 21 of the groove, which is greatly damaged by the groove processing. Therefore, there is no interface between the piezoelectric layer 2 and the internal electrodes 3A and 3B. Therefore, it is possible to prevent the first pillar 11a from collapsing. At the time of machining the second and subsequent grooves, since the groove 10a (gap) formed in the first one already exists, the stress at the time of machining becomes a refuge, and the piezoelectric element columns near the blade are less likely to be damaged, The second and subsequent piezoelectric element columns are less likely to collapse.

  In this way, a piezoelectric actuator 100 in which a plurality of piezoelectric element columns 11 (including 11a) are formed on the piezoelectric member 2 is obtained. The piezoelectric actuator 100 can be deformed by applying a driving voltage to a required piezoelectric element column 11.

Here, a comparative example will be described with reference to FIG. However, the same reference numerals as those in the embodiment are used.
As shown in FIG. 4A, the piezoelectric member 12 of this comparative example does not have the region 1C where the internal electrodes 3A and 3B do not exist. Therefore, as shown in FIG. 4 (b), when the first processed groove 10 is formed between the central region 1A and the end region 1B1, the peripheral portion 31 of the processed groove 10 defines the first processed groove 10a. When forming, since there is no escape space for stress during processing such as grooves and gaps, damage is received by receiving the load of the blade over the entire surface.

  After that, as shown in FIG. 4C, when the second groove is processed, the region 32 that should originally be a piezoelectric element column becomes a damaged region at the time of the first processing. It falls down due to the load during processing.

  On the other hand, according to the manufacturing method of the piezoelectric actuator of the present embodiment, a plurality of pillars have a region processed at equal pitch, and the groove processing of the region processed at equal pitch has no internal electrode. Since the groove processing is started from the region and the groove processing is performed at an equal pitch in one direction, the column collapse of the piezoelectric element column can be reduced.

  And the piezoelectric actuator manufactured with this manufacturing method of a piezoelectric actuator does not fall down of a column of a piezoelectric element, and a reliable operation characteristic is obtained.

  Further, according to the above piezoelectric actuator, since the internal electrode is not exposed on at least one side surface of the first column formed in the region processed at an equal pitch, the column collapse of the piezoelectric element column And a highly reliable operation characteristic can be obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. In addition, FIG. 5 is a principal front explanatory view for explaining the embodiment.
Here, the internal electrodes 3A and 3B are not present on both side surfaces 21 and 22 of the first groove 10a. Even if comprised in this way, the effect similar to the said 1st Embodiment can be acquired.

Here, the connection between the piezoelectric actuator manufactured by the manufacturing method described above and the wiring member will be described.
In the piezoelectric actuator of each of the embodiments described above, in the case of the bi-pitch method in which every other column is driven, as shown in FIG. 6, individual wiring electrodes of a wiring member (for example, FPC) 15 that gives a driving waveform to the piezoelectric element column 11 16A and the common wiring electrode 16B are connected to the individual electrode 4 and the common electrode 5B of the piezoelectric member 1. At this time, as shown in FIG. 7, even when the individual wiring electrode 16A is displaced by one column and the wiring member 15 is joined, the piezoelectric element column 11a located at the end has the area of the internal electrode 3A. Since the area is smaller than the area of the internal electrode 3A of the other pillar 11 and the electrostatic capacity is different, it is possible to easily detect a defect by electrical inspection.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 8 is an explanatory front view of the piezoelectric actuator according to the embodiment.
Here, the internal electrodes 3A and 3B are not exposed on the side surface 21 of the first groove 10a, but the processed grooves other than the first one including the last processed groove 10 (hereinafter referred to as “groove 10z”). Internal electrodes 3 </ b> A and 3 </ b> B are exposed on the side surface of 10. As described above, since only the first is susceptible to damage during processing, the second and subsequent grooves are processed by the presence of the previously processed grooves even if the internal electrodes are exposed. I can escape. In addition, by doing so, the last piezoelectric element column formed by the last processed groove 10z can be used as the driving piezoelectric element, preventing the piezoelectric member from being unnecessarily elongated and reducing the cost. Can be made.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 9 is an explanatory front view of a main part of the piezoelectric actuator according to the embodiment.
Here, the internal electrodes are not present on both side surfaces of the first piezoelectric element column 11a formed by the groove processing. In this way, even if high-speed machining with a large load at the time of grooving is performed, the first processed piezoelectric element has no internal electrode, and the interface between the piezoelectric element and the electrode that is the starting point of column collapse is Therefore, column collapse can be reliably prevented and productivity can be improved.

Next, a different example of the fifth embodiment of the present invention will be described with reference to FIGS. 10 and 11 are explanatory front views of the piezoelectric actuator according to the embodiment.
Here, as shown in FIG. 10, the number of the internal electrodes 3A, 3B exposed on the side surface of the first piezoelectric element column 11a formed by the groove processing is determined as the number of the internal electrodes 3A of the piezoelectric element column 11 at the center. The number of exposures is 3B. Even if configured in this way, when the first groove is processed, the number of interfaces between the piezoelectric layer and the internal electrode that are the starting points of the column collapse is smaller than the central portion, and the occurrence of the column collapse can be reduced. it can.

  In this case, the position where the internal electrode does not partially exist is preferably on the deep position side in the groove depth direction (the base side of the piezoelectric element column) as shown in FIG. This is because the position where the load applied to the pillar during processing is deeper is greater.

  Further, as shown in FIG. 11, the number of internal electrodes less than the central piezoelectric element column is not only the end of the first piezoelectric element column 11a but also the number of internal electrodes of the second piezoelectric element column 11b. You may do it.

Next, the groove processing means will be described with reference to the schematic explanatory view of FIG.
The dicing blade 9 held by the flange 42 is rotating clockwise at a speed of 30000 rpm. The piezoelectric member 1 joined to the base member 8 serving as a workpiece moves from the right to the left in FIG. Since the dicing saw can set the position accuracy in the Y direction (perpendicular to the paper surface) with high accuracy, it is excellent for fine pitch processing. In the case of a wire saw, processing at a pitch of 50 μm or less is impossible because the wire diameter is about 50 μm at the minimum. In the case of a dicing saw, since a blade of 10 to 15 μm can be manufactured, a processing pitch of about 40 μm can be handled. Therefore, a dicing saw is preferable as the groove processing means.

Next, the relationship between the present invention and the aspect ratio of the piezoelectric element column will be described with reference to FIG.
This piezoelectric actuator is a piezoelectric actuator having a processing pitch: 42 μm (piezoelectric element column width: 22 μm, processing groove width: 20 μm) and a processing groove depth of 360 μm. When the aspect ratio of the piezoelectric element column is 15 or more, the first column collapse tends to occur remarkably, and it is extremely effective to apply the present invention to such a piezoelectric actuator.

  Next, an embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 14 is a cross-sectional explanatory view along the liquid chamber longitudinal direction (direction perpendicular to the liquid chamber arrangement direction) of the liquid discharge head, and FIG. 15 is also necessary along the liquid chamber short direction (liquid chamber arrangement direction). FIG.

  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 portion 107 that also serves as a supply path for supplying liquid ink to the pressurized liquid chamber 106, and a common liquid chamber 108 for supplying recording liquid to the plurality of pressurized liquid chambers 106 are formed. is doing. The recording liquid is supplied to the common liquid chamber 108 from a liquid tank (not shown) via a supply path.

  The diaphragm member 102 includes a first layer 121 and a second layer 122, and is adhesively bonded to the chamber plate 101B constituting the flow path substrate 101. The diaphragm member 2 is formed with a deformable portion (diaphragm region) 102A which becomes a wall surface of the liquid chamber 106, and an island-like protrusion (hereinafter referred to as an island-shaped protrusion) on the opposite side of the diaphragm region 102A to the liquid chamber 106. It is also referred to as an “island-shaped convex portion.”) 102B is formed. The diaphragm member 102 is also formed with a thick portion 102D at a position corresponding to the liquid chamber interval wall portion 106A of the flow path substrate 101.

  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.

  Then, the piezoelectric actuator 100 according to the present invention is disposed outside the surface of the diaphragm member 102 (on the side opposite to the pressurized liquid chamber 106), and a wiring member 15 such as an FPC is connected thereto. The piezoelectric element column 11 driven by the piezoelectric actuator 110 is adhesively bonded to the island-shaped convex portion 102B of the diaphragm member 102, and the non-driven piezoelectric element column 11 is formed on the thick portion 102D corresponding to the liquid chamber interval wall portion 106A. Adhesive bonding.

  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 configured by the second 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 the liquid discharge head configured as described above, for example, when the voltage applied to the piezoelectric element column 11 for driving the piezoelectric member 1 of the piezoelectric actuator 100 is lowered from the reference potential, the piezoelectric element column 11 contracts, and the diaphragm member When the diaphragm region 102A of 102 is lowered and the volume of the pressurized liquid chamber 106 expands, the ink flows into the pressurized liquid chamber 106, and then the voltage applied to the piezoelectric element pillars 11 is increased in the stacking direction. The ink in the pressurizing liquid chamber 106 is pressurized by expanding and deforming the diaphragm region 102A in the direction of the nozzle 104 and contracting the volume of the pressurizing liquid chamber 106, and droplets of the recording liquid are ejected from the nozzle 104. (Injected).

  Then, by returning the voltage applied to the piezoelectric element column 11 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. At this time, the common liquid chamber Ink is filled into the pressurized liquid chamber 106 from 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.

  Here, the endmost piezoelectric element column 11 a of the piezoelectric actuator 100 exists at the position of the wall portion of the flow path substrate 101. Since the piezoelectric element column 11a is not used as a driving piezoelectric element column, it is not necessary to unnecessarily increase the length of the piezoelectric member 1 regardless of the presence or absence of the internal electrode. As described above, the piezoelectric actuator 100 does not fall down and can stably discharge droplets.

  That is, if the width of the piezoelectric element column 11a is widened in order to prevent column collapse, the length of the piezoelectric member 1 needs to be unnecessarily increased, and the column width supporting the partition wall 51A of the flow path plate 51 is different from other channels. Therefore, there is a channel variation in the ejection characteristics. Therefore, it is preferable that the piezoelectric element columns for supporting the partition walls have the same specifications for all channels.

  As described above, since the liquid discharge head includes the piezoelectric actuator according to the present invention, the liquid discharge head can be a long head that does not collapse and has little variation in droplet discharge characteristics.

Next, an example of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention will be described with reference to FIGS. FIG. 16 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 17 is a plan view for explaining a main portion of the mechanism portion.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in a main scanning direction by main and sub guide rods 231 and 232 which are guide members horizontally mounted on left and right side plates 221A and 221B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

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

  Each of the recording heads 234 has two nozzle rows, one of the two nozzle rows of one head 234a is a black (K) droplet, and the other two nozzle rows are cyan (C) liquid. The two nozzle rows of the other head 234b eject magenta (M) droplets, and the other two nozzle rows eject yellow (Y) droplets. Note that, here, a four-color droplet is ejected with a two-head configuration, but each of the four colors can be ejected with one head in a four-nozzle row arrangement per head.

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

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

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

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

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

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

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

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

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 237 and pressed against the conveying belt 251 by the leading end pressing roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  As described above, since the image forming apparatus includes the liquid discharge head according to the present invention as a recording head, there is no variation in specific droplet discharge and stable droplet discharge characteristics can be obtained, so that a high-quality image can be formed. it can.

Next, another example of the image forming apparatus according to the present invention including the liquid discharge head according to the present invention will be described with reference to FIG. FIG. 18 is a schematic configuration diagram of the entire mechanism unit of the apparatus.
This image forming apparatus is a line type image forming apparatus, has an image forming unit 402 and the like inside the apparatus main body 401, and can supply a large number of recording media (sheets) 403 on the lower side of the apparatus main body 401. A paper tray 404 is provided, a sheet 403 fed from the sheet feeding tray 404 is taken in, a required image is recorded by the image forming unit 402 while the sheet 403 is conveyed by the conveying mechanism 405, and then the side of the apparatus main body 401. The paper 403 is discharged to a paper discharge tray 406 attached to the printer.

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

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

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

  Here, the recording head 411 is arranged to eject droplets of each color in the order of black, cyan, magenta, and yellow from the upstream side in the paper conveyance direction, but the arrangement and the number of colors are not limited to this. Further, as the line-type head, one or a plurality of heads provided with a plurality of nozzle rows for discharging droplets of each color at 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 paper 403 in the paper feed tray 404 is separated one by one by a paper feed roller (half-moon roller) 421 and a separation pad (not shown) and fed into the apparatus main body 401, and is registered along the guide surface 423 a of the transport guide member 423. It is sent between 425 and the conveyor belt 433, and is sent to the conveyor belt 433 of the conveyor mechanism 405 via the guide member 426 at a predetermined timing.

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

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

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

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

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

  As described above, since the image forming apparatus includes the recording head including the liquid ejection head according to the present invention, there is no variation in specific droplet ejection, and stable droplet ejection characteristics can be obtained, thereby forming a high-quality image. can do.

  In the above embodiment, the present invention has been described with reference to an example in which the present invention is applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this, and as described above, for example, an image forming apparatus such as a printer / fax / copier multifunction machine. In addition, the present invention can also be applied to an image forming apparatus using a liquid other than the narrowly defined ink or a fixing processing liquid.

DESCRIPTION OF SYMBOLS 1 Piezoelectric member 1C Area | region without an internal electrode 2 Piezoelectric layer 3A, 3B Internal electrode 10 Groove 10a First groove 11 Piezoelectric element column 11a First piezoelectric element column 100 Piezoelectric actuator 101 Flow path substrate 102 Vibration plate member 103 Nozzle plate 106 Pressurized liquid chamber 233 Carriage 234a, 234b Recording head (liquid ejection head)
411k, 411c, 411m, 411y Recording head (liquid ejection head)

Claims (10)

Manufacture of a piezoelectric actuator in which a plurality of pillars are formed by performing groove processing in order from the end on a laminated piezoelectric member in which a piezoelectric material and internal electrodes are laminated, and at least a part of the plurality of pillars can be deformed In the method
The plurality of pillars have a region processed at an equal pitch,
The method for manufacturing a piezoelectric actuator is characterized in that the grooving of the region processed at an equal pitch starts the grooving from a region where the internal electrode does not exist and performs the grooving of the equal pitch in one direction.   2. The method of manufacturing a piezoelectric actuator according to claim 1, wherein the last groove processing of the region processed at the equal pitch is performed in a region where the internal electrode exists.   The method for manufacturing a piezoelectric actuator according to claim 1, wherein a groove is formed using a dicing saw.   A piezoelectric actuator manufactured by the manufacturing method according to claim 1. In the piezoelectric actuator in which a plurality of pillars are formed by performing groove processing in order from the end on a laminated piezoelectric member in which a piezoelectric material and internal electrodes are laminated, and at least a part of the plurality of pillars is deformable.
A piezoelectric actuator characterized in that an internal electrode is not exposed on at least one side surface of a column formed first in a region processed at an equal pitch. In the piezoelectric actuator in which a plurality of pillars are formed by performing groove processing in order from the end on a laminated piezoelectric member in which a piezoelectric material and internal electrodes are laminated, and at least a part of the plurality of pillars is deformable.
The number of internal electrodes exposed on at least one side surface of the column formed first in a region processed at an equal pitch is equal to the number of internal electrodes exposed on the side surface of the column located in the center. Piezoelectric actuator characterized by less than.   The internal electrode exposed on at least one side surface of the column formed first has fewer internal electrodes on the base side of the column than the internal electrode exposed on the side surface of the column located in the center. The piezoelectric actuator according to claim 6.   The piezoelectric actuator according to any one of claims 4 to 7, wherein the aspect ratio of the pillars in the region processed at an equal pitch is 15 or more.   A liquid discharge head comprising the piezoelectric actuator according to claim 4.   An image forming apparatus comprising the liquid discharge head according to claim 9.

Images