JP4506124B2 - Inkjet head, inkjet recording apparatus - Google Patents

Description

The present invention is an inkjet head that prints on a recording medium by ejecting ink, relates to an ink jet recording equipment.

  In an ink jet recording apparatus (ink jet printer), an ink jet head distributes ink supplied from an ink tank to pressure chambers, and selectively applies pulsed pressure to the pressure chambers to eject ink from nozzles. As a pressure generating means for selectively applying pressure to the pressure chamber, an actuator unit in which a plurality of piezoelectric sheets made of ceramic are laminated may be used.

  As an example of such an ink jet head, Patent Document 1 discloses that a first piezoelectric element that deforms by applying voltage and applies pressure to ink in a pressure chamber is bonded to a position facing each pressure chamber. The second piezoelectric element for detecting the vibration is arranged on the opposite side of the first piezoelectric element across the pressure chamber. In the inkjet head, when ink is ejected from the nozzle, a voltage is applied from a driver to deform the first piezoelectric element. Then, the second piezoelectric element detects the vibration of the ink in the pressure chamber and outputs it to the vibration cancellation control circuit. When receiving the vibration detection signal, the vibration cancellation control circuit outputs a pulse generation signal to the driver so as to cause the first piezoelectric element to generate a vibration for canceling the vibration of the ink in the pressure chamber. A voltage is applied to the element from the driver. In this way, since the vibration of the ink in the pressure chamber that occurs when ink is ejected from the nozzle is attenuated, it is possible to obtain an ink jet head that can perform stable ink ejection up to a high frequency range.

JP-A-5-162313 (page 3, FIG. 1)

  However, in the inkjet head described in Patent Document 1, when increasing the amount of ink ejected from the nozzle, it is necessary to apply a high voltage to the first piezoelectric element to obtain a large deformation of the first piezoelectric element. . Therefore, it is necessary to enlarge the driver for applying a voltage to the first piezoelectric element and increase the allowable amount of the applied voltage. As a result, the cost of the inkjet head increases.

Accordingly, the present invention also increase the ink discharge amount, a small, yet inkjet head to be low cost, and to provide an ink jet recording equipment.

Means for Solving the Problems and Effects of the Invention

The ink jet head of the present invention is fixed to one surface of a pressure chamber block composed of one or a plurality of sheet-like members, in which a plurality of pressure chambers communicating with nozzles are arranged along a plane. A main actuator block that changes the volume of the pressure chamber, an auxiliary actuator block that is fixed to a surface opposite to the one surface of the pressure chamber block, and changes the volume of the pressure chamber; and the auxiliary actuator block On the other hand, a nozzle block fixed on the side opposite to the pressure chamber block and having the nozzle formed thereon is provided. The main actuator block includes a plurality of first individual electrodes disposed at positions facing the plurality of pressure chambers, a first common electrode provided across the plurality of pressure chambers, and the first A first piezoelectric sheet sandwiched between a common electrode and the first individual electrode, wherein the auxiliary actuator block has a plurality of second individual electrodes disposed at positions facing the plurality of pressure chambers, respectively. a second common electrode provided over the pressure chamber of the multiple, a plurality of piezoelectric sheets which are stacked together including a second piezoelectric sheet sandwiched between the second common electrode by the second individual electrodes together and a, when an electric field is applied said second piezoelectric sheet which is displaced by the piezoelectric effect, sandwiched lamination direction by the piezoelectric sheet does not spontaneously displaced without affected by the electric field To have.

As a result , the deformation of the two actuator blocks contributes to the volume change of the pressure chamber, so that the level of the signal supplied to each actuator block can be lowered while maintaining the ink discharge amount, and the ink discharge amount is increased. Can be made. Therefore, a device including an inkjet head can have a long life, a small size, and a low cost.

  Further, in the present invention, the main actuator block includes a contact portion that is electrically insulated from the first individual electrode and the first common electrode and disposed adjacent to the first individual electrode, The second individual electrode is preferably electrically connected to the contact portion through a through hole that penetrates the pressure chamber block. As a result, the portion where the first individual electrode is electrically connected and the contact point of the second individual electrode can be connected by a common signal line (FPC: flexible flat cable), which facilitates assembly of the inkjet head. can do. In other words, since the electrically connected portion of the first individual electrode and the contact point of the second individual electrode exist on the same plane, it becomes possible to join them to the FPC almost simultaneously, Easy to assemble.

In the present invention, the pressure chamber has a parallelogram having two acute corners or a planar shape of a parallelogram with rounded corners, and the first individual electrode faces the pressure chamber. A main electrode region having a shape similar to that of the pressure chamber, and an auxiliary electrode region drawn from one acute angle portion in the longitudinal direction of the main electrode region and disposed adjacent to the acute angle portion. The first individual electrodes and the pressure chambers are arranged in a matrix so that the auxiliary electrode region is located between two other main electrode regions, and the contact portion is located with respect to the main electrode region. It is preferable that the auxiliary electrode region is disposed on the opposite side. Thereby, electrical connection to the second individual electrode can be further facilitated.
In the present invention, the second individual electrode is drawn out from the main electrode region having a similar shape to the pressure chamber disposed at a position facing the pressure chamber, and the other acute angle portion with respect to the longitudinal direction of the main electrode region. It is preferable that the leading end portion of the pulling portion and the contact portion are electrically joined. Thereby, electrical connection to the second individual electrode can be further facilitated.
In the present invention, it is preferable that the plurality of adjacent second individual electrodes are electrically connected to each other by a connection electrode. Thereby, since the 2nd separate electrode of an auxiliary actuator block is electrically connected by the connecting electrode, it is not necessary to supply an independent signal to each 2nd separate electrode. Therefore, the wiring structure is simplified.

  In the present invention, the main actuator block is composed of the first individual electrode, the first common electrode, and the first piezoelectric sheet, and an external electric field is applied in the polarization direction of the main actuator block. When the first piezoelectric sheet expands and contracts in a direction crossing the polarization direction, the volume of the pressure chamber is changed, and the first individual electrode is opposite to the first piezoelectric sheet side. It is preferable that there is nothing on the side that restricts the expansion and contraction of the first piezoelectric sheet. As a result, the main actuator block makes a unimorph type displacement, so that a large amount of displacement can be obtained.

In the present invention, the nozzle block has an ink ejection region in which a plurality of the nozzles respectively corresponding to the pressure chambers are arranged on a surface opposite to the pressure block, and the pressure chambers and the nozzles The auxiliary actuator block formed with a hole for connecting the nozzle, the pressure chamber block, and the nozzle block constitute a flow path unit in which an ink flow path having the nozzle is formed at one end. preferable. This makes it possible to arrange the nozzles with high density.

In another aspect, the present invention is an inkjet recording apparatus including an inkjet head that ejects ink droplets, and a drive signal generation device that generates a drive signal supplied to the inkjet head. Is fixed to one surface of the pressure chamber block, and a pressure chamber block made of one or a plurality of sheet-like members, in which a plurality of pressure chambers communicating with the nozzle are arranged along a plane. A main actuator block that changes the volume, and an auxiliary actuator block that is fixed to a surface opposite to the one surface of the pressure chamber block and changes the volume of the pressure chamber. The main actuator block includes a plurality of first individual electrodes arranged at positions facing the plurality of pressure chambers, a first common electrode provided across the plurality of pressure chambers, and the first common electrode. A first piezoelectric sheet sandwiched between an electrode and the first individual electrode, wherein the auxiliary actuator block has a plurality of second individual electrodes disposed at positions facing the plurality of pressure chambers; A second common electrode provided across the pressure chamber, and a second piezoelectric sheet sandwiched between the second common electrode and the second individual electrode. The drive signal generation device is a pulse generation means for generating a pulse train signal supplied to the first individual electrode, and an auxiliary drive signal supplied to the second individual electrode, and independently ejects ink from the nozzle. Auxiliary drive signal generating means for generating an auxiliary drive signal having an amplitude that is not caused by the above and having a frequency higher than that of the pulse train signal, and the first individual electrode related to the nozzle that should eject ink droplets based on image data the pulse supplying means for supplying a pulse train signal, with and an auxiliary drive signal supply means for supplying the auxiliary drive signal to said second individual electrodes related to the nozzle to eject at least ink droplets, the auxiliary Supply of the auxiliary drive signal generated by the drive signal generation means to the second individual electrode, and the pulse train signal generated by the pulse generation means And supply to the individual electrodes, at timing to reduce the volume of the pressure chamber, are synchronized to match.

  Thus, the drive voltage can be lowered by supplying the auxiliary drive signal and the pulse train signal to one pressure chamber. Since an auxiliary drive signal having a frequency higher than that of the pulse train signal is supplied, fluid crosstalk caused by pressure fluctuations in the common ink chamber communicating with the plurality of pressure chambers can be suppressed. Further, when a plurality of types of pulse train signals each having the number of pulses corresponding to the number of ink droplets ejected corresponding to one dot on the medium are used, the second and subsequent pulses and the auxiliary drive signal in one cycle It will be easier to synchronize.

  In the present invention, it is preferable that the frequency of the auxiliary drive signal generated by the auxiliary drive signal generation unit is n times (n is a natural number of 2 or more) the frequency of the pulse train signal generated by the pulse generation unit. As a result, the auxiliary drive signal and the pulse train signal can be synchronized, and the power consumption can be reduced by lowering the level of the pulse train signal.

  In the present invention, it is preferable that the pulse train signal generated by the pulse generator includes a pulse having an amplitude that causes ink ejection from the nozzles alone.

  In the present invention, it is preferable that the second individual electrodes of the auxiliary actuator block are electrically connected to each other. Thereby, it is not necessary to supply an independent signal to each second individual electrode. Therefore, the wiring structure is simplified.

  In the present invention, it is preferable that the second individual electrodes of the auxiliary actuator block are electrically independent from each other. This makes it possible to supply a plurality of types of auxiliary drive signals to the second individual electrode of the auxiliary actuator block. Therefore, the control becomes simple.

  Also, at this time, the auxiliary drive signal generated by the auxiliary drive signal generating means is applied to the second individual electrode sharing the pressure chamber with the first individual electrode supplied with the pulse train signal generated by the pulse generating means. It may be supplied to at least one of the plurality of adjacent second individual electrodes. Thereby, if the auxiliary drive signal and the pulse train signal are synchronized, structural crosstalk caused by the displacement of the first piezoelectric sheet being transmitted to the first individual electrode can be suppressed.

  Further, at this time, the planar shape of the pressure chamber is a parallelogram having two acute angle portions or a parallelogram shape with rounded corner portions, and the first individual electrode is positioned at a position facing the pressure chamber. The auxiliary electrode region, and the auxiliary electrode region connected to the main electrode region and disposed in a direction from the main electrode region toward one acute angle portion of the pressure chamber. The first individual electrodes and the pressure chambers are arranged in a matrix so that the region is located between the main electrode regions of the other two first individual electrodes, and the auxiliary drive signal generating means generates The auxiliary drive signal is supplied with the first individual electrode adjacent to the acute angle portion or the corner portion opposite to the auxiliary electrode region of the first individual electrode to which the pulse train signal generated by the pulse generation means is supplied, and the Shared pressure chamber The second may be supplied to the individual electrodes. Thereby, structural crosstalk and fluid crosstalk can be effectively suppressed.

  At this time, the auxiliary drive signal generated by the auxiliary drive signal generating means may be supplied to all of the second individual electrodes. Thereby, structural crosstalk and fluidic crosstalk can be more effectively suppressed with low power consumption.

Further, at this time, the nozzle further includes a nozzle block fixed to the side opposite to the pressure chamber block with respect to the auxiliary actuator block and formed with the nozzle, and a hole for connecting the pressure chamber and the nozzle is provided. The formed auxiliary actuator block, the pressure chamber block, and the nozzle block constitute a flow path unit, and in the flow path unit, a common ink chamber communicated with the plurality of pressure chambers , and , the common plurality of individual ink passages from the ink chamber outlet through the pressure chamber leading to said nozzle has been made form, the pressure chamber communicating to the pulse train signal is opposed to the first individual electrode supplied wherein adjacent the outlet of the common ink chamber, the second individual electrode and the outlet from and opposite to the pressure chamber communicating with another outlet, auxiliary drive signal subjected to It may be I present at least one shall be. Thereby, structural crosstalk and fluid crosstalk can be suppressed by simple control.
At this time, the auxiliary drive signal generating means may generate a sine wave signal, and a width of a pulse constituting the pulse train signal may correspond to an odd multiple of a half wavelength of the sine wave signal. Thereby, energy consumption can be suppressed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic view of an ink jet printer having an ink jet head according to a first embodiment of the present invention. An ink jet printer 101 shown in FIG. 1 is a color ink jet printer having four ink jet heads 1. The printer 101 includes a paper feed unit 111 on the left side in the drawing and a paper discharge unit 112 on the right side in the drawing.

  Inside the printer 101, a paper transport path is formed through which paper is transported from the paper feed unit 111 toward the paper discharge unit 112. A pair of feed rollers 105 a and 105 b that sandwich and convey a sheet as an image recording medium are disposed immediately downstream of the sheet feeding unit 111. The paper is fed from the left to the right in the figure by the pair of feed rollers 105a and 105b. Two belt rollers 106 and 107 and an endless conveyance belt 108 wound around the rollers 106 and 107 are disposed in the middle of the sheet conveyance path. The outer peripheral surface of the conveyor belt 108, i.e., the conveyor surface, is subjected to silicon treatment. While the sheet conveyed by the pair of feed rollers 105 a and 105 b is held on the conveyor surface of the conveyor belt 108 by its adhesive force, The belt roller 106 can be conveyed toward the downstream side (right side) by being rotated clockwise (in the direction of the arrow 104) in the drawing.

  Holding members 109a and 109b are disposed at the insertion and discharge positions of the sheet with respect to the belt roller 106, respectively. The holding members 109a and 109b are for pressing the paper against the transport surface of the transport belt 108 so that the paper on the transport belt 108 does not float from the transport surface, and securely sticking the paper onto the transport surface.

  A peeling mechanism 110 is provided immediately downstream of the conveying belt 108 along the sheet conveying path. The peeling mechanism 110 is configured to peel the paper adhered to the conveyance surface of the conveyance belt 108 from the conveyance surface and send it to the right paper discharge unit 112.

  The four inkjet heads 1 have a head body 70 at the lower end. The head main bodies 70 each have a rectangular cross section, and are arranged close to each other so that the longitudinal direction thereof is a direction perpendicular to the paper transport direction (the vertical direction in FIG. 1). That is, the printer 101 is a line printer. The bottom surfaces of the four head bodies 70 are opposed to the sheet conveyance path, and a large number of nozzles 8 (see FIG. 7) having a minute diameter are provided on these bottom surfaces. Magenta, yellow, cyan, and black inks are ejected from each of the four head bodies 70.

  The head main body 70 is disposed so that a small amount of gap is formed between the lower surface of the head main body 70 and the conveyance surface of the conveyance belt 108, and a sheet conveyance path is formed in the gap portion. With this configuration, when the paper transported on the transport belt 108 sequentially passes immediately below the four head bodies 70, each color ink is ejected from the nozzle toward the upper surface of the paper, that is, the printing surface. A desired color image can be formed on the paper.

  The inkjet printer 101 includes a maintenance unit 117 for automatically performing maintenance on the inkjet head 1. The maintenance unit 117 is provided with four caps 116 for covering the lower surfaces of the four head bodies 70, a purge mechanism (not shown), and the like.

  The maintenance unit 117 is located at a position (retracted position) immediately below the sheet feeding unit 111 when printing is performed by the inkjet printer 101. When a predetermined condition is satisfied after the printing is finished (for example, when a state in which no printing operation is performed continues for a predetermined time or when the printer 101 is turned off), the four head bodies It moves to a position immediately below 70, and at this position (cap position), the cap 116 covers the lower surface of the head body 70 to prevent ink from drying at the nozzle portion of the head body 70. .

  The belt rollers 106 and 107 and the conveyor belt 108 are supported by a chassis 113. The chassis 113 is placed on a cylindrical member 115 disposed below the chassis 113. The cylindrical member 115 is rotatable around a shaft 114 attached at a position off the center. Therefore, if the upper end height of the cylindrical member 115 changes with the rotation of the shaft 114, the chassis 113 moves up and down accordingly. When the maintenance unit 117 is moved from the retracted position to the cap position, the cylindrical member 115 is rotated in advance by an appropriate angle so that the chassis 113, the conveyor belt 108, and the belt rollers 106 and 107 are moved by an appropriate distance from the position shown in FIG. It is necessary to secure the space for the maintenance unit 117 to move down.

  In a region surrounded by the conveyor belt 108, a substantially rectangular parallelepiped shape (supporting the conveyor belt 108 and the conveyor belt 108) is supported from the inner peripheral side by contacting the lower surface of the conveyor belt 108 at a position facing the inkjet head 1, that is, the upper side. A guide 121 having the same width is disposed.

  FIG. 2 is an external perspective view of the ink jet head shown in FIG. 3 is a cross-sectional view taken along line III-III in FIG. The inkjet head 1 includes a head main body 70 having a rectangular planar shape extending in the main scanning direction for ejecting ink onto a sheet, and an ink that is disposed above the head main body 70 and supplied to the head main body 70. And a base block 71 on which two ink reservoirs 3 are formed.

  The head body 70 includes a flow path unit 4 in which an ink flow path is formed, and a plurality of actuator units 21 bonded to the upper surface of the flow path unit 4. Both the flow path unit 4 and the actuator unit 21 have a configuration in which a plurality of sheet-like members are stacked and bonded to each other. Further, a flexible printed circuit (FPC: Flexible Printed Circuit) 50, which is a power supply member, is bonded to the upper surface of the actuator unit 21, and the FPC 50 is drawn upward while being bent in FIG. The base block 71 is made of a metal material such as stainless steel. The ink reservoir 3 in the base block 71 is a substantially rectangular parallelepiped hollow region formed along the longitudinal direction of the base block 71.

  The lower surface 73 of the base block 71 protrudes downward from the periphery in the vicinity of the opening 3b. The base block 71 is in contact with the flow path unit 4 only in the portion 73a near the opening 3b of the lower surface 73. Therefore, a region other than the portion 73a near the opening 3b on the lower surface 73 of the base block 71 is separated from the head main body 70, and the actuator unit 21 is disposed in this separated portion.

  The base block 71 is bonded and fixed in a recess formed on the lower surface of the grip portion 72 a of the holder 72. The holder 72 includes a gripping portion 72a and a pair of flat projections 72b extending from the upper surface of the gripping portion 72a at a predetermined interval in a direction orthogonal thereto. The FPC 50 bonded to the actuator unit 21 is disposed along the surface of the protruding portion 72b of the holder 72 via an elastic member 83 such as a sponge. And driver IC80 is installed on FPC50 arrange | positioned on the protrusion part 72b surface of the holder 72. FIG. The FPC 50 is electrically joined to both by soldering so as to transmit the drive signal output from the driver IC 80 to the actuator unit 21 (described later in detail) of the head body 70.

  Since the heat sink 82 having a substantially rectangular parallelepiped shape is closely disposed on the outer surface of the driver IC 80, the heat generated in the driver IC 80 can be efficiently dissipated. A substrate 81 is disposed above the driver IC 80 and the heat sink 82 and outside the FPC 50. Seal members 84 are disposed between the upper surface of the heat sink 82 and the substrate 81, and between the lower surface of the heat sink 82 and the FPC 50, and the seal members 84 are bonded to each other.

  The driver IC 80 connected thereto via the substrate 81 and the FPC 50 generates a pulse for driving the actuator unit 21 and constitutes a pulse control device 200 for supplying the generated pulse to the actuator unit 21. . The pulse control device 200 is connected to a control unit 113 for controlling the ink jet printer 101, and controls each ink jet head 1 corresponding to magenta, yellow, cyan, and black based on communication with the control unit 113. Do.

  FIG. 4 is a plan view of a head body included in the inkjet head depicted in FIG. In FIG. 4, the ink reservoir 3 formed in the base block 71 is virtually drawn with a broken line. The two ink reservoirs 3 extend in parallel with each other at a predetermined interval along the longitudinal direction of the head body 70. The two ink reservoirs 3 each have an opening 3a at one end, and are always filled with ink by communicating with an ink tank (not shown) through the opening 3a. A large number of openings 3b are provided in each ink reservoir 3 along the longitudinal direction of the head main body 70, and connect each ink reservoir 3 and the flow path unit 4 as described above. A large number of the openings 3 b are arranged close to each other along the longitudinal direction of the head body 70. A pair of openings 3b communicating with one ink reservoir 3 and a pair of openings 3b communicating with the other ink reservoir 3 are arranged in a staggered manner.

  In the area where the openings 3b are not arranged, a plurality of actuator units 21 having a trapezoidal planar shape are arranged in a staggered pattern in a pattern opposite to the pair of the openings 3b. The parallel opposing sides (upper side and lower side) of each actuator unit 21 are parallel to the longitudinal direction of the head body 70. Further, a part of the oblique sides of the adjacent actuator units 21 overlap in the width direction of the head main body 70.

  FIG. 5 is an enlarged view of a region surrounded by a one-dot chain line drawn in FIG. As shown in FIG. 5, the opening 3b provided in each ink reservoir 3 communicates with a manifold 5 which is a common ink chamber, and the tip of each manifold 5 branches into two to form a sub-manifold 5a. Yes. In addition, two sub-manifolds 5a branched from the adjacent openings 3b extend from the two oblique sides of the actuator unit 21 in plan view. That is, below the actuator unit 21, a total of four sub-manifolds 5 a that are separated from each other extend along the parallel opposing sides of the actuator unit 21.

  The lower surface of the flow path unit 4 corresponding to the adhesion area of the actuator unit 21 is an ink ejection area. A large number of nozzles 8 are arranged in a matrix on the surface of the ink discharge area, as will be described later. In order to simplify the drawing, only a few of the nozzles 8 are illustrated in FIG. 5, but in reality, they are arranged over the entire ink discharge region.

  FIG. 6 is an enlarged view of a region surrounded by a dashed line drawn in FIG. 5 and 6 show a state where a plane in which a large number of pressure chambers 10 in the flow path unit 4 are arranged in a matrix is viewed from a direction perpendicular to the ink ejection surface. Each pressure chamber 10 has a parallelogram-shaped planar shape with rounded corners, and the longer diagonal line is parallel to the width direction of the flow path unit 4. One end of each pressure chamber 10 communicates with the nozzle 8, and the other end communicates with the sub-manifold 5 a as a common ink flow path via the aperture 12. A first individual electrode 35 similar to the pressure chamber 10 and having a slightly smaller planar shape than the pressure chamber 10 is formed on the actuator unit 21 at a position overlapping each pressure chamber 10 in plan view. In FIG. 6, only some of the multiple first individual electrodes 35 are depicted for the sake of simplicity. 5 and 6, the pressure chambers 10 and the apertures 12 and the like that are to be drawn with broken lines in the actuator unit 21 or the flow path unit 4 are drawn with solid lines for easy understanding of the drawings.

  In FIG. 6, the plurality of virtual rhombus regions 10x each accommodating the pressure chambers 10x are arranged in a direction A (first direction) and a direction B (second) so as to share each side without overlapping each other. Are arranged adjacently in a matrix in two directions. The arrangement direction A is the longitudinal direction of the inkjet head 1, that is, the extending direction of the sub-manifold 5a, and is parallel to the shorter diagonal line of the rhombic region 10x. The arrangement direction B is an oblique side direction of the rhombus region 10x that forms an obtuse angle θ with the arrangement direction A. The pressure chamber 10 has a common center position with the corresponding rhombus region 10x, and the contour lines of both are separated from each other in plan view.

  The pressure chambers 10 adjacently arranged in a matrix in two directions of the arrangement direction A and the arrangement direction B are separated along the arrangement direction A by a distance corresponding to 37.5 dpi. Further, 16 pressure chambers 10 are arranged in the arrangement direction B in one ink ejection region. The pressure chambers at both ends in the arrangement direction B are dummy and do not contribute to ink ejection.

  A pressure chamber group composed of a plurality of pressure chambers 10 arranged in a matrix has a similar shape to the planar shape of the actuator unit 21. The plurality of pressure chambers 10 form a plurality of pressure chamber rows along the arrangement direction A shown in FIG. The pressure chamber rows are the first pressure chamber row 11a and the second pressure chamber row according to the relative position with respect to the sub-manifold 5a when viewed from the direction (third direction) perpendicular to the paper surface of FIG. 11b, a third pressure chamber row 11c, and a fourth pressure chamber row 11d. Each of the first to fourth pressure chamber rows 11a to 11d is periodically arranged in the order of 11c → 11d → 11a → 11b → 11c → 11d → ... → 11b from the upper side to the lower side of the actuator unit 21. Has been placed.

  In the pressure chambers 10a constituting the first pressure chamber row 11a and the pressure chambers 10b constituting the second pressure chamber row 11b, a direction (fourth direction) orthogonal to the arrangement direction A when viewed from the third direction. ), The nozzle 8 is unevenly distributed on the lower side of the drawing sheet of FIG. And the nozzle 8 is located in the lower end part of the corresponding rhombus area | region 10x. On the other hand, in the pressure chambers 10c constituting the third pressure chamber row 11c and the pressure chambers 10d constituting the fourth pressure chamber row 11d, the nozzle 8 is unevenly distributed on the upper side in FIG. 5 in the fourth direction. Yes. And the nozzle 8 is located in the upper end part of the corresponding rhombus area | region 10x, respectively. In the first and fourth pressure chamber rows 11a and 11d, when viewed from the third direction, more than half of the pressure chambers 10a and 10d overlap the sub-manifold 5a. In the second and third pressure chamber rows 11b and 11c, the entire region of the pressure chambers 10b and 10c does not overlap the sub-manifold 5a when viewed from the third direction. Therefore, for the pressure chambers 10 belonging to any pressure chamber row, the width of the sub-manifold 5a is made as wide as possible while the nozzle 8 communicating therewith does not overlap the sub-manifold 5a, and ink is supplied to each pressure chamber 10. It can be supplied smoothly.

  Next, the cross-sectional structure of the head main body 70 will be further described with reference to FIG. FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6, and the pressure chambers 10a belonging to the first pressure chamber row 11a are depicted in FIG. As can be seen from FIG. 7, each nozzle 8 communicates with the sub-manifold 5a via the pressure chamber 10 (10a) and the aperture 12. In this manner, the individual ink flow paths 32 extending from the outlet 13 of the sub-manifold 5 a to the nozzle 8 through the aperture 12 and the pressure chamber 10 are formed in the head main body 70 for each pressure chamber 10.

  As is clear from FIG. 7, the pressure chamber 10 and the aperture 12 are provided at different levels. As a result, as shown in FIG. 6, in the flow path unit 4 corresponding to the ink discharge area below the actuator unit 21, the aperture 12 communicating with one pressure chamber 10 is moved to a pressure chamber adjacent to the pressure chamber. 10 and the same position in plan view. As a result, the pressure chambers 10 are in close contact with each other and are arranged at high density, so that high-resolution image printing is realized by the inkjet head 1 having a relatively small occupation area.

  The head main body 70 has a total of 11 sheets of the actuator unit 21, the cavity plate 22, the actuator plate 23, the base plate 24, the aperture plate 25, the supply plate 26, the manifold plates 27, 28 and 29, the cover plate 30 and the nozzle plate 31 from the top. The sheet-like member has a laminated structure laminated with an adhesive. Among these, the flow path unit 4 is composed of 10 plates excluding the actuator unit 21.

  The actuator unit 21 is a portion in which three piezoelectric sheets 41 to 43 (see FIG. 8A) are stacked and electrodes are arranged as described later, so that only the uppermost layer becomes an active layer when an electric field is applied. (Hereinafter referred to simply as “layer having an active layer”), and the remaining two layers are inactive layers. The cavity plate 22 is a metal plate provided with a number of substantially diamond-shaped openings corresponding to the pressure chambers 10. As will be described later, the actuator plate 23 is also a portion in which three piezoelectric sheets 45 to 47 (see FIG. 8A) are laminated and electrodes are arranged so that only the central layer becomes an active layer when an electric field is applied. The upper layer and the lower layer of the actuator plate 23 are inactive layers (hereinafter referred to simply as “layers having an active layer”). The actuator plate 23 is provided with a communication hole 14 a between the pressure chamber 10 and the aperture 12 and a communication hole 14 b from the pressure chamber 10 to the nozzle 8 with respect to one pressure chamber 10 of the cavity plate 22. The base plate 24 is a metal plate provided with a communication hole between the pressure chamber 10 and the aperture 12 and a communication hole from the pressure chamber 10 to the nozzle 8 for one pressure chamber 10 of the cavity plate 22. The aperture plate 25 is a metal plate provided with a communication hole from the pressure chamber 10 to the nozzle 8 in addition to the aperture 12 for one pressure chamber 10 of the cavity plate 22. The supply plate 26 is a metal plate provided with a communication hole between the aperture 12 and the sub-manifold 5 a and a communication hole from the pressure chamber 10 to the nozzle 8 for one pressure chamber 10 of the cavity plate 22. The manifold plates 27, 28, and 29 are metal plates each provided with a communication hole from the pressure chamber 10 to the nozzle 8 for one pressure chamber 10 of the cavity plate 22 in addition to the sub-manifold 5 a. The cover plate 30 is a metal plate in which a communication hole from the pressure chamber 10 to the nozzle 8 is provided for one pressure chamber 10 of the cavity plate 22. The nozzle plate 31 is a metal plate in which the nozzles 8 are provided for one pressure chamber 10 of the cavity plate 22.

  These ten sheets 21 to 31 are laminated in alignment with each other so that the individual ink flow paths 32 as shown in FIG. 7 are formed. The individual ink flow path 32 first extends upward from the outlet 13 of the sub-manifold 5a, extends horizontally at the aperture 12, then further upwards, extends horizontally again at the pressure chamber 10, and then for a while. From the diagonally downward direction away from the nozzle, the nozzle 8 is directed vertically downward to the nozzle 8.

  Next, the configuration of the actuator unit 21 stacked on the uppermost cavity plate 22 in the flow path unit 4 and the actuator plate 23 stacked between the cavity plate 22 and the base plate 24 will be described. FIG. 8 shows an upper layer portion of the head body 70, and FIG. 8A is an enlarged cross-sectional view showing a state where the actuator unit 21 is laminated on the upper surface of the cavity plate of the flow path unit 4 and the actuator plate 23 is laminated on the lower surface. (B) is a top view which shows the arrangement | positioning condition of a 1st individual electrode, (c) is a top view which shows the arrangement | positioning condition of a 2nd individual electrode.

  The actuator unit 21 shown in FIG. 8A includes three piezoelectric sheets 41 to 43 each having a thickness of about 15 μm and formed to be the same. These piezoelectric sheets 41 to 43 are continuous layered flat plates (continuous flat plate layers) so as to be disposed across a number of pressure chambers 10 formed in one ink discharge region in the head main body 70. . Since the piezoelectric sheets 41 to 43 are arranged as a continuous flat plate layer across a large number of pressure chambers 10, the first individual electrodes 35 can be arranged on the piezoelectric sheet 41 at a high density by using, for example, a screen printing technique. It is possible. Therefore, the pressure chambers 10 formed at positions corresponding to the first individual electrodes 35 can be arranged with high density, and high-resolution images can be printed. The piezoelectric sheets 41 to 43 are made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity.

  A first individual electrode 35 is formed on the uppermost piezoelectric sheet 41. Between the uppermost piezoelectric sheet 41 and the lower piezoelectric sheet 42, a first common electrode 34 having a thickness of about 2 μm formed on the entire surface of the sheet is interposed. Note that no electrode is disposed between the piezoelectric sheet 42 and the piezoelectric sheet 43. Both the first individual electrode 35 and the first common electrode 34 are made of a metal material such as Ag—Pd.

  As shown in FIG. 8B, the first individual electrode 35 has a main electrode region 36 having a substantially rhombic planar shape that is substantially similar to the pressure chamber 10, as shown in FIG. A circular land portion (auxiliary electrode region) 37 having a diameter of approximately 160 μm and electrically connected to the main electrode region 36 is provided at the tip of one of the acute angle portions 36 extending from the tip. The land portion 37 is made of gold including glass frit, for example. The land portion 37 is electrically joined to a contact provided on the FPC 50.

  The first common electrode 34 is grounded in a region not shown. As a result, the first common electrode 34 is kept at the same ground potential in the regions corresponding to all the pressure chambers 10. Further, as shown in FIG. 8A, each land portion 37 of the first individual electrode 35 is controlled so that the potential can be controlled for each of the first individual electrodes 35 corresponding to each pressure chamber 10. Each individual electrode 35 is connected to the driver IC 80 via the FPC 50 including another lead wire independent (see FIGS. 2 and 3).

  As shown in FIG. 8A, the actuator plate 23 includes three piezoelectric sheets 45 to 47 formed to have the same thickness of about 15 μm. These piezoelectric sheets 45 to 47 are continuous layered flat plates (continuous flat plate layers) so as to be disposed across a number of pressure chambers 10 formed in one ink discharge region in the head main body 70. . The piezoelectric sheets 45 to 47 are arranged as a continuous flat plate layer across a large number of pressure chambers 10, so that, for example, by using a screen printing technique, the above-described first on the piezoelectric sheet 47 as shown in FIG. The second individual electrodes 38 having the same shape as the main electrode region 36 of the one individual electrode 35 can be arranged with high density. The second individual electrode 38 has a thickness of approximately 1 μm, and is formed at a position corresponding to each pressure chamber 10 as with the individual electrode 35 described above. Adjacent second individual electrodes 38 are connected by an elongated connection electrode 39. The connection electrode 39 is bridged between the central portions of the mutually opposing sides of the adjacent second individual electrodes 38. Accordingly, the four connection electrodes 39 and the four second individual electrodes 38 connected by the four connection electrodes 39 form a substantially rhombus shape. Note that the piezoelectric sheets 45 to 47 are made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity as in the piezoelectric sheets 41 to 43 described above.

  Between the piezoelectric sheet 45 and the lower piezoelectric sheet 46, a second common electrode 40 having a thickness of about 2 μm formed on the entire surface of the sheet is interposed. Note that no electrode is disposed between the piezoelectric sheet 45 and the cavity plate 22 and between the piezoelectric sheet 47 and the base plate 24. The second individual electrode 38, the connecting electrode 39, and the second common electrode 40 are all made of a metal material such as an Ag—Pd system.

  The actuator unit 21, the cavity plate 22, and the actuator plate 23 have one through hole 61 extending therebetween. The through hole 61 passes through the entire thickness of the actuator unit 21, the entire thickness of the cavity plate 22, and the piezoelectric sheets 45 and 46 of the actuator plate 23. A conductor 62 is embedded in the through hole 61. As shown in FIG. 8C, a diagonal line extends from one acute angle portion of one specific second individual electrode 38 (the acute angle portion where the land portion 37 is not provided in the opposed first individual electrode 35). An elongated drawer portion 38a extends in the direction. The conductor 62 electrically connects the distal end portion of the lead portion 38 a and the contact portion 63 provided on the piezoelectric sheet 41. The contact portion 63 is joined to an independent lead wire of the FPC 50 so that the same potential can be applied to all the second individual electrodes 38 by the driver IC 80. Since the contact portion 63 is thus provided, when the land portion 37 of the first individual electrode 35 and the contact portion 63 of the second individual electrode 38 are connected by the FPC 50, they can be joined on the same plane. As a result, the inkjet head 1 can be easily assembled. Moreover, since the contact part 63 is arrange | positioned on the opposite side to the land part 37 of the 1st individual electrode 35, the electrical connection with respect to the 2nd individual electrode 38 can be made still easier. The connecting electrode 39 may be pulled out to the side surface of the flow path unit 4 and connected to the FPC 50. The second common electrode 40 is grounded in a region (not shown), and is kept at the same ground potential in regions corresponding to all the pressure chambers 10.

  Next, a method for driving the actuator unit 21 and the actuator plate 23 will be described. The polarization direction of the piezoelectric sheet 41 in the actuator unit 21 is the thickness direction. In other words, the actuator unit 21 has one piezoelectric sheet 41 on the upper side (that is, the side away from the pressure chamber 10) as a layer in which the active layer exists and two lower sheets (that is, the side closer to the pressure chamber 10). It has a so-called unimorph type configuration in which the piezoelectric sheets 42 and 43 are inactive layers. There is nothing on the upper surface of the piezoelectric sheet 41 that restricts deformation of the piezoelectric sheets 41 to 44. Therefore, the displacement amount of the piezoelectric sheets 41 to 44 can be increased. When the first individual electrode 35 is set to a positive or negative predetermined potential, for example, if the electric field and polarization are in the same direction, the electric field application portion sandwiched between the electrodes in the piezoelectric sheet 41 functions as an active layer (pressure generation unit), Shrink in the direction perpendicular to the polarization direction due to the piezoelectric transverse effect. On the other hand, the piezoelectric sheets 42 and 43 are not spontaneously displaced because they are not affected by the electric field. Therefore, the piezoelectric sheets 42 and 43 are not displaced in the direction perpendicular to the polarization direction between the upper piezoelectric sheet 41 and the lower piezoelectric sheets 42 and 43. A difference is caused in the distortion, and the entire piezoelectric sheets 41 to 43 try to be deformed so as to be convex on the non-active side (unimorph deformation). At this time, as shown in FIG. 8A, the lower surfaces of the piezoelectric sheets 41 to 43 are fixed to the upper surface of the cavity plate 22 defining the pressure chambers. Deforms so that it is convex to the side. For this reason, the volume of the pressure chamber 10 decreases, and the ink pressure increases. When the electric potential of the first individual electrode 35 is changed so that the electric field and the polarization are in the opposite directions (hereinafter, the electric potential is referred to as the reverse electric potential after the change), the piezoelectric sheets 41 to 43 protrude on the active side. As a result, the ink pressure drops.

  The polarization direction of the piezoelectric sheet 46 in the actuator plate 23 is the thickness direction thereof. That is, the actuator plate 23 has a configuration in which the central piezoelectric sheet 46 is an active layer and the upper and lower piezoelectric sheets 45 and 47 are inactive layers. Therefore, if all the second individual electrodes 38 are set to a predetermined positive or negative potential, for example, if the electric field and the polarization are in the same direction, the electric field application portion sandwiched between the electrodes in the piezoelectric sheet 46 is the active layer (pressure generation Part) and contracts in a direction perpendicular to the polarization direction due to the piezoelectric transverse effect. On the other hand, since the piezoelectric sheets 45 and 47 are not affected by the electric field and are not spontaneously displaced, the direction perpendicular to the polarization direction is between the piezoelectric sheet 46 in the central layer and the piezoelectric sheets 45 and 47 in the upper and lower layers. Therefore, the piezoelectric sheets 45 to 47 as a whole tend to be deformed so as to protrude toward the inactive side. At this time, as shown in FIG. 8A, the upper surfaces of the piezoelectric sheets 45 to 47 (that is, the upper surface of the actuator plate 23) are fixed to the upper surface of the cavity plate 22 that partitions the pressure chamber 10. Specifically, the piezoelectric sheets 45 to 47 are deformed so as to protrude toward the pressure chamber 10. For this reason, the volume of the pressure chamber 10 decreases and the ink pressure increases. When the electric potential of the second individual electrode 38 is changed so that the electric field and the polarization are in the opposite directions, the piezoelectric sheets 45 to 47 are conversely convex on the active side, and the ink pressure drops.

  In the case where ink is ejected from the nozzle 8 with such a configuration of the actuator unit 21 and the actuator plate 23, the actuator unit 21 sets the first individual electrode 35 to the same potential in advance, and each time there is an ejection request, the first The individual electrode 35 is once set to a reverse potential, and then set to the same potential at a predetermined timing. At this time, positive and negative potentials of a sine wave (see FIG. 10) pulse pattern are repeatedly applied to the second individual electrode 38, and the first individual electrode 35 and the second individual electrode 38 cause the inside of the pressure chamber 10. Ink is ejected from the nozzle 8. In this case, at the timing when the first individual electrode 35 becomes a reverse potential, the ink pressure drops and the ink is sucked into the pressure chamber 10 from the manifold 5 side. Thereafter, at the timing when the first individual electrode 35 is set to the same potential again, the pressure on the ink rises and the ink is ejected.

  In this embodiment, in order to eject ink from the nozzle 8, the same potential and the reverse potential to the first individual electrode 35 must have a predetermined potential difference, and a pulse having this potential difference is used. The amplitude of is 10V. Moreover, the amplitude which is applied to the second individual electrode 38 and is a positive and negative potential difference is 10 V or less.

  Next, functions of the pulse control device 200 including the substrate 81 and the driver IC 80 will be described in detail. FIG. 9 is a functional block diagram of the pulse controller 200. Each functional unit shown in FIG. 9 includes a CPU (Central Processing Unit) that is an arithmetic processing device mounted on the substrate 81, and a ROM (Read Only) that stores a program executed by the CPU and data used for the program. Memory), a RAM (Random Access Memory) for temporarily storing data during program execution, and each circuit configured in the driver IC 80 function.

  The pulse control device 200 includes a communication unit 201, a storage unit 202, a signal generation unit 203, and a signal supply unit 204. The communication unit 201 communicates with the control unit 113. The control unit 113 converts the gradation-represented image data to be printed separated into magenta, yellow, cyan, and black and timing data to be printed based on the image data of the inkjet head 1 corresponding to each color. Transmit to the pulse controller 200. The communication unit 201 receives the image data and the timing data, and stores them in the storage unit 202 so that they can be referred to from other functions.

  The storage unit 202 includes a ROM and a RAM, and includes a pulse pattern storage unit 202a and an image data storage unit 202b. The pulse pattern storage unit 202a is configured by a ROM, and when the number of ejected ink droplets is three, the number of ejected ink droplets is two, and the number of the three types of pulse patterns (one pulse rising timing and (Falling timing) is stored. The number of ejected ink droplets corresponds to the density value of the gradation data included in the image data.

  The image data storage unit 202b is constituted by a RAM, and temporarily stores the image data and timing data received from the control unit 113.

  The signal generator 203 includes an ejection pulse generator 203a and an auxiliary drive signal generator 203b. The ejection pulse generation unit 203a generates an ejection pulse signal supplied to the first individual electrode 35 from the pulse pattern stored in the pulse pattern storage unit 202a. The ejection pulse signal is a pulse train signal in which each pulse having the rising timing and the falling timing stored in the pulse pattern storage unit 202a has a predetermined voltage wave height. The auxiliary drive signal generator 203 b generates an auxiliary drive signal supplied to the second individual electrode 38 using a clock signal generated in the pulse control device 200. The auxiliary drive signal is a sine wave signal having a higher frequency than the ejection pulse signal.

  10A, 10B, and 10C show ejection pulse signals generated by the ejection pulse generation unit 203a. In this embodiment, the ejection pulse signal is a pulse train signal including 1 to 3 concave rectangular waves, and a rectangular wave having a width of AL (Acoustic Length) from the falling timing to the rising timing is ejected. According to the number (1 to 3) of ink droplets to be formed, the ink droplets are continuous at intervals of AL. The number of concave rectangular waves corresponds to the number of ejected ink droplets. 10A shows an ejection pulse signal when the number of ejected ink droplets is one, FIG. 10B shows an ejection pulse signal when there are two ink droplets, and FIG. 10C shows three ejection pulse signals. The discharge pulse signal in the case of is shown. The amplitude, that is, the wave height of the ejection pulse signal is determined to a value that does not cause ink to be ejected alone.

  FIG. 10D shows an auxiliary drive signal generated by the auxiliary drive signal generator 203b. The auxiliary drive signal is a sine wave having a frequency 10 times that of the ejection pulse signal shown in FIGS. 10 (a), 10 (b), and 10 (c). That is, if the period of the ejection pulse signal is T1, the period T2 of the auxiliary drive signal is 1/10 of the period T1. The amplitude of the auxiliary drive signal is determined to a value that does not cause ink to be ejected from the nozzles alone.

  As shown in FIGS. 10A to 10D, the falling timing of the concave rectangular wave of the ejection pulse signal coincides with the timing at which the auxiliary drive signal takes the minimum value. Between the falling timing of the concave rectangular wave and the next rising timing, auxiliary driving signals for 1.5 cycles are included. Therefore, the rising timing of the next concave rectangular wave after the ejection pulse signal coincides with the timing at which the auxiliary drive signal takes the maximum value. In this way, the timing at which the actuator unit 21 reduces the volume of the pressure chamber 10 and the timing at which the actuator plate 23 reduces the volume of the pressure chamber 10 are matched, and the actuator unit 21 increases the volume of the pressure chamber 10. Since the timing at which the actuator plate 23 expands the volume of the pressure chamber 10 is matched, the voltage amplitudes of the ejection pulse signal and the auxiliary drive signal cannot be individually ejected, and are extremely small. As a value, ink can be ejected from the nozzle. Therefore, the cost of the driver IC 80 can be reduced and greatly reduced, and the energy consumption can be minimized.

  The signal supply unit 204 includes an ejection pulse supply unit 204a and an auxiliary drive signal supply unit 204b. The ejection pulse supply unit 204a applies the three types of ejection pulse signals generated by the ejection pulse generation unit 203a to the first individual electrode 35 based on the gradation data included in the image data stored in the image data storage unit 202b. Supply. In other words, the discharge pulse signal shown in FIG. 10A is supplied to a pixel having a low density, and the discharge pulse signal shown in FIG. 10C is supplied to a pixel having a high density, and the pixel having an intermediate density. Is supplied with an ejection pulse signal shown in FIG.

  The auxiliary drive signal supply unit 204b transmits the auxiliary drive signal generated by the auxiliary drive signal generation unit 203b to all the actuator plates 23 from the contact unit 63 via the conductors 62 in the through holes 61 regardless of the contents of the image data. This is supplied to the second individual electrode 38.

  Next, the operation procedure of the pulse control device 200 will be described. FIG. 11 is a flowchart showing an operation procedure of the pulse control device 200. The pulse control device 200 is on standby for receiving image data and timing data transmitted from the control unit 113 when the ink jet printer 101 is turned on.

  When the image data and timing data are transmitted from the control unit 113, the process proceeds to step S101 (hereinafter abbreviated as S101, the same applies to other steps), and the communication unit 201 receives the transmitted image data and timing data. . The communication unit 201 that has received the image data receives the image data and the timing data, and stores them in the image data storage unit 202b so that they can be referred to from other functions.

  After that, the process proceeds to S102, where the discharge pulse generation unit 203a generates three types of discharge pulse signals, and the auxiliary drive signal generation unit 203b generates auxiliary drive signals. In step S103, the ejection pulse supply unit 204a supplies the ejection pulse signal to the first individual electrode 35 related to one nozzle based on the gradation data included in the image data stored in the image data storage unit 202b. It is determined whether or not to be supplied, and if it is to be supplied, which of the three types of ejection pulse signals shown in FIGS. 10A, 10B, and 10C is to be supplied is determined. Next, in S104, it is determined whether or not there is a nozzle (next nozzle) that has not been determined in S103. If it is determined that there is the next nozzle 8 (S104: YES), the process returns to S103 and the same processing is performed. If it is determined that there is no next nozzle 8 (S104: NO), the process proceeds to S105.

  In S105, the ejection pulse supply unit 204a supplies an ejection pulse signal conforming to the determination in S103 to each first individual electrode 35 at a predetermined timing. At this time, the ejection pulse signal is not supplied to the first individual electrode determined in S103 that the ejection pulse signal should not be supplied. At the same time, the auxiliary drive signal supply unit 204b supplies the auxiliary drive signal generated by the auxiliary drive signal generation unit 203b in S102 to the second individual electrode. Thereafter, the flowchart of FIG. 11 ends.

  In the inkjet head 1 according to the first embodiment as described above, since the second individual electrode 38 of the actuator plate 23 is electrically connected by the connecting electrode 39, the contact 63 and the FPC 50 are connected. It is not necessary to supply an independent signal to each second individual electrode 38. Therefore, the wiring structure of the inkjet head 1 is simplified. Further, since the deformation of the actuator unit 21 and the actuator plate 23 both contribute to the volume change of the pressure chamber 10, the pulse amplitude of the pulse train signal supplied to the actuator unit 21 is reduced while maintaining the ink discharge amount from the nozzle 8. In addition, the ink discharge amount can be increased. For this reason, it is not necessary to make the driver IC 80 large enough to generate a high voltage signal as the amount of ink discharged from the nozzles 8 increases, and a small driver IC can be used. The rise can be suppressed. In addition, since the volume of the pressure chamber 10 is changed by deformation caused by both the actuator unit 21 and the actuator plate 23, the deformation amount of the actuator unit 21 can be reduced while maintaining the ink discharge amount. Can be lengthened.

  In addition, since the second individual electrode 38 is supplied with an auxiliary drive signal having a frequency higher than that of the pulse train signal, fluid crosstalk caused by pressure fluctuations in the sub-manifold 5a communicating with the plurality of pressure chambers 10 is suppressed. can do. The fluid crosstalk is a change in ink pressure that occurs when ink in the pressure chamber 10 is ejected from the nozzle 8 in accordance with a change in volume of the pressure chamber 10, and is transmitted to the ink in the sub-manifold 5a. The ink in the chamber 10 is affected. Therefore, by giving a small pressure change to the ink in the pressure chamber 10 by the volume change of the pressure chamber 10 of the second individual electrode 38 by the auxiliary drive signal, it is possible to make the fluid crosstalk occur in all the pressure chambers 10. Thus, the same state as that in which the fluid crosstalk is suppressed can be obtained. That is, since a pressure change that is not fluid crosstalk is given in the pressure chamber 10, a desired ink discharge can be achieved by applying pressure to the ink in the pressure chamber 10 by a change in the volume of the pressure chamber 10 corresponding to the pressure change. The speed and ink discharge amount can be adjusted.

  Further, when ink is ejected onto the recording medium, when a plurality of types of pulse train signals each having a pulse number corresponding to the number of ink droplets ejected corresponding to one dot on the medium are used, within one cycle It becomes easier to synchronize the second and subsequent pulses with the auxiliary drive signal. Moreover, since the flow path unit 4 is configured as described above, the nozzles 8 can be arranged with high density.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 12 shows an upper layer portion of the head main body 170 of the ink jet head 301 according to the second embodiment of the present invention. FIG. 12 (a) shows the actuator unit 21 on the upper surface of the cavity plate 22 of the flow path unit 4 and the lower surface thereof. FIG. 5 is an enlarged cross-sectional view showing a state in which actuator plates 223 are stacked, (b) is a plan view showing an arrangement state of first individual electrodes 35, and (c) is a plane showing an arrangement state of second individual electrodes 238. FIG. The inkjet head 301 of the present embodiment is different from the inkjet head 1 of the first embodiment in that the second individual electrodes 238 are not connected to each other.

  As shown in FIGS. 12A, 12 </ b> B, and 12 </ b> C, the second individual electrode 238 is formed at the same location as the second individual electrode 38 described above. The second individual electrode 238 is not connected by the connecting electrode 39 described above. The second individual electrode 238 has substantially the same shape as the main electrode region 36 of the first individual electrode 35. From one acute angle portion of each of the second individual electrodes 238 (the acute angle portion where the land portion 37 is not provided in the opposing first individual electrode 35), an elongated lead portion 238a is extended in the diagonal direction. The leading end portion of the lead portion 238a and the contact portion 63 provided on the piezoelectric sheet 41 are electrically connected by a conductor 62 embedded in a through hole 261 formed for each contact portion 63. ing. The through hole 261 passes through the entire thickness of the actuator unit 21, the entire thickness of the cavity plate 22, and the piezoelectric sheets 45 and 46 of the actuator plate 223 in the same manner as the through hole 61 described above.

  The contact portions 63 are respectively joined to independent lead wires of the FPC 50 so that the driver IC 80 can control the potentials independent of the second individual electrodes 38. Thus, since the contact part 63 is provided, the effect similar to the above can be acquired. The second common electrode 40 is grounded in a region (not shown), and is kept at the same ground potential in the regions corresponding to all the pressure chambers 10.

  Next, functions of the pulse control device 200 in the present embodiment will be described. In the present embodiment, the pulse control device 200 functions in the same manner as in the first embodiment except that the function of the auxiliary drive signal supply unit 204b is different. In the present embodiment, the auxiliary drive signal supply unit 204b is independently connected to each of the second individual electrodes 238 and faces the first individual electrode 35 to which the ejection pulse signal is given (the pressure chamber is shared). Auxiliary drive signal is supplied to the second individual electrode 238. Hereinafter, details of this point will be described with reference to FIG.

  FIG. 13 is a flowchart showing an operation procedure of the pulse control device 200 in the present embodiment. S201 to S203 are the same as the operations from S101 to S103 described in FIG.

  In S204, the auxiliary drive signal supply unit 204b supplies the auxiliary drive signal shown in FIG. 10D to the second individual electrode 238 related to one nozzle based on the image data stored in the image data storage unit 202b. Decide if you should. Specifically, when an ejection pulse signal is supplied to the first individual electrode 35 sharing the pressure chamber 10, it is determined that an auxiliary drive signal should be supplied to the second individual electrode 238.

  As a modification, in addition to the second individual electrode 238 when the ejection pulse signal is supplied to the first individual electrode 35 sharing the pressure chamber 10 with the second individual electrode 238, the second individual electrode 238 is adjacent to the second individual electrode 238. An auxiliary drive signal may be supplied to at least one of the plurality of second individual electrodes 238. In this way, if the auxiliary drive signal and the pulse train signal are synchronized, structural crosstalk caused by the displacement of the piezoelectric sheet 41 being transmitted to the first individual electrode 35 can be suppressed.

  As another modification, in addition to the second individual electrode 238 when the ejection pulse signal is supplied to the first individual electrode 35 sharing the pressure chamber 10 with the second individual electrode 238, the first individual electrode The auxiliary drive signal may be supplied to the second individual electrode 238 sharing the pressure chamber 10 with the two first individual electrodes 35 adjacent to the acute angle portion opposite to the land portion 37 of the 35. By doing so, the above-described structural crosstalk can be effectively suppressed.

  As yet another modification, the auxiliary drive signal may be supplied to all the second individual electrodes. By doing so, the same effect as in the first embodiment can be obtained.

  As another modification, in addition to the second individual electrode 238 when the discharge pulse signal is supplied to the first individual electrode 35 sharing the pressure chamber 10 with the second individual electrode 238, An auxiliary drive signal may be supplied to the second individual electrode 238 facing the pressure chamber communicating with another outlet 13 adjacent to the outlet 13 of the sub-manifold 5a communicating with the opposing pressure chamber 10.

  Next, in S205, it is determined whether or not there is a nozzle (next nozzle) that has not yet been determined in S203 and S204. If it is determined that there is the next nozzle 8 (S205: YES), the process returns to S203 and the same processing is performed. If it is determined that there is no next nozzle 8 (S205: NO), the process proceeds to S206.

  In S206, the ejection pulse supply unit 204a supplies an ejection pulse signal conforming to the determination in S203 to each first individual electrode 35 at a predetermined timing. At this time, the ejection pulse signal is not supplied to the first individual electrode 35 determined in step S203 that the ejection pulse signal should not be supplied. At the same time, the auxiliary drive signal supply unit 204b supplies the auxiliary drive signal generated by the auxiliary drive signal generation unit 203b in S202 only to the second individual electrode 238 to which the auxiliary drive signal should be supplied in S204. Thereafter, the flowchart of FIG. 13 ends.

  The ink jet head 301 according to the second embodiment as described above is almost the same except that the configuration related to the second individual electrode 238 is different, and thus the same effect as the ink jet head 1 according to the first embodiment can be obtained. it can. The effect that is caused by the difference in the configuration related to the second individual electrode 238 makes it possible to supply a plurality of types of auxiliary drive signals to the second individual electrode 238 of the actuator plate 223 individually, thereby simplifying the control. That is, since the second individual electrode 38 of the inkjet head 1 described above is connected by the connection electrode 39, when the auxiliary drive signal is supplied to the second individual electrode 38, all the second individual electrodes 38 are driven in the same manner. In the inkjet head 301 in the present embodiment, the auxiliary drive signal can be supplied only to the minimum necessary number of the second individual electrodes 238, so that the control becomes simple. In addition, power consumption for driving the second individual electrode 238 can be efficiently reduced.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. The ink jet head according to the present embodiment has the same structure as that of the ink jet head 1 according to the first embodiment, and is different from the first embodiment only in the function of the pulse control device 200. Therefore, in the following, description of the structure of the inkjet head is omitted, and the function of the pulse control device 200A will be described with reference to FIG. In FIG. 14, the same members as those in FIG.

  A pulse control device 200A illustrated in FIG. 14 includes a communication unit 201, a storage unit 202, a pulse pattern determination unit 211, and a signal generation unit 212. Whether the pulse pattern determination unit 211 should supply the ejection pulse signal to each first individual electrode 35 based on the gradation data and timing data included in the image data stored in the image data storage unit 202b. If it is to be supplied, it is determined which of the three types of ejection pulse signals shown in FIGS. 10A, 10B, and 10C is to be supplied.

  The signal generator 212 includes an ejection pulse generator 212a and an auxiliary drive signal generator 212b. In the present embodiment, the ejection pulse generator 212a is provided independently for each first individual electrode. Based on the determination by the pulse pattern determination unit 211, the ejection pulse generation unit 212a uses the pulse patterns stored in the pulse pattern storage unit 202a for each nozzle, as shown in FIGS. 10 (a), 10 (b), and 10 (c). One of the three types of ejection pulse signals shown in FIG. The auxiliary drive signal generator 212b generates an auxiliary drive signal supplied to the second individual electrode 38 using a clock signal generated in the pulse control device 200A.

  FIG. 15 is a flowchart showing an operation procedure of the pulse control device 200A in the present embodiment. The pulse control device 200 </ b> A waits for reception of image data and timing data transmitted from the control unit 113 when the ink jet printer 101 is turned on.

  When image data and timing data are transmitted from the control unit 113, the process proceeds to S301, and the communication unit 201 receives the transmitted image data and timing data. The communication unit 201 that has received the image data receives the image data and the timing data, and stores them in the image data storage unit 202b so that they can be referred to from other functions.

  Thereafter, the process proceeds to S302, and the pulse pattern determination unit 211 determines whether each nozzle 8 is a nozzle (ejection nozzle) 8 that ejects ink based on the image data and timing data stored in the image data storage unit 202b. Judgment in order. If it is determined that the nozzle 8 is not a discharge nozzle (S302: NO), the process proceeds to S305. If it is determined that the nozzle 8 is a discharge nozzle (S302: YES), the process proceeds to S303.

  In step S <b> 303, the pulse pattern determination unit 211 causes the nozzle 8 to select one of the three types of pulse patterns stored in the pulse pattern storage unit 202 based on the pixel gradation data in the image data corresponding to the nozzle 8. The pulse pattern of the ejection pulse signal supplied to the corresponding first individual electrode 35 is determined. Thereafter, the process proceeds to S304, where the pulse pattern data determined in S303 is stored in the register of the ejection pulse generation unit 212a, and the preparation for pulse generation is completed. Thereafter, the process proceeds to S305.

  Next, in S305, it is determined whether there is a nozzle (next nozzle) for which the pulse pattern determination in S303 has not yet been performed. If it is determined that there is the next nozzle 8 (S305: YES), the process returns to S302 and the same processing is performed. If it is determined that there is no next nozzle 8 (S305: NO), the process proceeds to S306.

  In S306, each ejection pulse generation unit 212a generates one of the three types of ejection pulse signals shown in FIGS. 10A, 10B, and 10C in accordance with the determination in S303 at a predetermined timing. The generated ejection pulse signal is supplied to the corresponding first individual electrode 35. At this time, the ejection pulse signal is not generated in the corresponding ejection pulse generation unit 212a for the nozzle determined not to be the ejection nozzle in S302. At the same time, the auxiliary drive signal generation unit 212b generates an auxiliary drive signal and supplies the generated auxiliary drive signal to all the second individual electrodes. Thereafter, the flowchart of FIG. 15 is terminated.

  Since the ink jet head according to the third embodiment as described above has the same configuration as the ink jet head 1 of the first embodiment described above, the same effect can be obtained. That is, since the second individual electrode 38 is connected by the connection electrode 39, it is not necessary to supply an independent signal to each second individual electrode 38. Further, since the first individual electrode 35 and the second individual electrode 38 are driven by the pulse train signal and the auxiliary drive signal, which contributes to the change in volume of the pressure chamber, the actuator 8 while maintaining the ink discharge amount from the nozzle 8 The amplitude of the pulse of the pulse train signal supplied to the unit 21 can be reduced and the ink discharge amount can be increased. Further, since the second individual electrode 35 is supplied with an auxiliary drive signal having a frequency higher than that of the pulse train signal, fluidic crosstalk caused by pressure fluctuations in the sub-manifold 5a communicating with the plurality of pressure chambers 10 is suppressed. can do.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. The ink jet head according to the present embodiment has the same structure as the ink jet head 301 according to the second embodiment, and the pulse control device 200A has functions of the pulse pattern determination unit 211 and the auxiliary drive signal generation unit 212b. Except for the difference, the third embodiment is the same as the third embodiment. Therefore, in the following, description of the structure of the inkjet head and the pulse control device 200A will be omitted, and the operation of the pulse pattern determination unit 211 and the auxiliary drive signal generation unit 212b will be described based on the flowchart of FIG. In the present embodiment, the ejection pulse generator 212a and the auxiliary drive signal generator 212b are provided independently for each first individual electrode and each second individual electrode. In FIG. 16, S401 to S404 are the same as the operations from S301 to S304 described in FIG.

  In S405, the pulse pattern determination unit 211 prepares to generate an auxiliary drive signal to be supplied to the second individual electrode 35 corresponding to the nozzle 8 determined to be a discharge nozzle in S402. The preparation here may be, for example, setting a flag provided for the nozzle so that the auxiliary drive signal generation unit 212b generates an auxiliary drive signal.

  Next, in S406, it is determined whether there is a nozzle (next nozzle) for which the pulse pattern determination in S403 has not yet been performed. If it is determined that there is the next nozzle 8 (S406: YES), the process returns to S402 and the same processing is performed. If it is determined that there is no next nozzle 8 (S406: NO), the process proceeds to S408.

  On the other hand, if it is determined in S402 that the nozzle 8 is not a discharge nozzle (S402: NO), the process proceeds to S407. In S407, the pulse pattern determination unit 211 determines whether or not there is a discharge nozzle around the nozzle. If there is no discharge nozzle in the vicinity (S407: NO), the process proceeds to S406. When there are discharge nozzles in the periphery (S407: YES), the process proceeds to S405, and preparations are made for generating an auxiliary drive signal to be supplied to the second individual electrode 238 corresponding to the nozzle.

  For example, when at least one of the plurality of first individual electrodes 35 adjacent to the first individual electrode 35 corresponding to the nozzle is a discharge nozzle, it is determined that there is a discharge nozzle around the nozzle. When at least one of the two first individual electrodes 35 adjacent to the acute angle portion on the opposite side to the land portion 37 of the first individual electrode 35 corresponding to the discharge nozzle is a first individual electrode corresponding to the nozzle 8 This is a case where the first individual electrode 35 facing the pressure chamber 10 communicating with another outlet 13 adjacent to the outlet 13 of the sub-manifold 5a communicating with the pressure chamber 10 facing the electrode 35 is a discharge nozzle.

  In S <b> 408, each ejection pulse generation unit 212 a generates an ejection pulse signal conforming to the determination in S <b> 403 at a predetermined timing, and supplies the generated ejection pulse signal to the corresponding first individual electrode 35. At this time, with respect to the nozzle 8 determined not to be a discharge nozzle in S402, a discharge pulse signal is not generated in the corresponding discharge pulse generation unit 212a. At the same time, each auxiliary drive signal generator 212b generates an auxiliary drive signal, and supplies the generated auxiliary drive signal to the corresponding second individual electrode 238. Thereafter, the flowchart of FIG. 16 ends.

  The ink jet head according to the fourth embodiment as described above has the same configuration as that of the ink jet head 301 of the second embodiment described above, and therefore the same effect can be obtained. That is, a plurality of types of auxiliary drive signals can be individually supplied to the second individual electrode 238 of the actuator plate 223, so that control is simplified and power consumption for driving the second individual electrode 238 is also efficient. Can be reduced.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims. For example, the embodiment described above is configured to generate a pulse using the pulse pattern stored in the pulse pattern storage unit, but is not limited to such a configuration, and includes a pulse pattern storage unit. Instead, a configuration may be used in which all pulse patterns are formed each time a pulse is generated.

  Further, the frequency of the auxiliary drive signal may not be a natural number multiple of the frequency of the ejection pulse signal. In the embodiment described above, ink is ejected from the nozzle in the direction from the pressure chamber toward the actuator plate, but the direction perpendicular to the direction from the pressure chamber toward the actuator plate (for example, perpendicular to the paper surface of FIG. 8). The ink may be ejected from the nozzles in the direction).

  In the first embodiment, the connection electrodes are provided between the adjacent second individual electrodes, but the connection electrodes are not necessarily adjacent if the second individual electrodes can be electrically connected to each other. It is not necessary to provide each between the second individual electrodes. Further, in the first embodiment, only one through hole is provided, but two or more through holes may be provided. Further, the waveform of the ejection pulse signal is not limited to that described above, and can be changed as appropriate. Further, the auxiliary drive signal and the ejection pulse signal may not be synchronized so as to coincide with each other at the timing of decreasing the volume of the pressure chamber. The ejection pulse signal may include a pulse having an amplitude that causes ink ejection from the nozzles alone.

  In the above-described embodiment, the pressure chamber, the first individual electrode, and the second individual electrode have a parallelogram plane shape and are arranged in a matrix shape, but the configuration is limited to such a configuration. The shape of the pressure chamber, the first individual electrode, and the second individual electrode may be arbitrarily set.

1 is a schematic view of an ink jet printer having an ink jet head according to a first embodiment of the present invention. It is an external appearance perspective view of the inkjet head shown in FIG. It is sectional drawing in the III-III line of FIG. FIG. 3 is a plan view of a head body included in the inkjet head depicted in FIG. 2. It is an enlarged view of the area | region enclosed with the dashed-dotted line drawn in FIG. FIG. 6 is an enlarged view of a region surrounded by an alternate long and short dash line depicted in FIG. 5. It is sectional drawing in the VII-VII line of FIG. The upper layer part of the head body is shown, (a) is an enlarged cross-sectional view showing a situation where the actuator unit is laminated on the upper surface of the cavity plate of the flow path unit and the actuator plate is laminated on the lower surface, and (b) is a first individual It is a top view which shows the arrangement | positioning condition of an electrode, (c) is a top view which shows the arrangement | positioning condition of a 2nd separate electrode. It is a functional block diagram of the pulse control device in a 1st embodiment. The ejection pulse signal and auxiliary drive signal which an ejection pulse generation part and an auxiliary drive signal generation part generate | occur | produce are shown, (a) is a figure which shows the ejection pulse signal in case the number of the ink droplets ejected is one. (B) is a figure which shows the discharge pulse signal in case the number of the ink droplets discharged is two, (c) is a figure which shows the discharge pulse signal in case the three ink droplets are discharged. (D) is a figure which shows the auxiliary drive signal which an auxiliary drive signal generation part produces | generates. It is a flowchart which shows the operation | movement procedure of a pulse control apparatus. The upper layer part of the head main body 70 of the inkjet head 301 by the 2nd Embodiment of this invention is shown, (a) is the actuator unit 21 on the upper surface of the cavity plate 22 of the flow path unit 4, and the actuator plate 223 on the lower surface. FIG. 4 is an enlarged cross-sectional view showing a stacked state, (b) is a plan view showing an arrangement state of first individual electrodes 35, and (c) is a plan view showing an arrangement state of second individual electrodes 238. FIG. It is a flowchart which shows the operation | movement procedure of the pulse control apparatus in 2nd Embodiment. It is a functional block diagram of the pulse control device in the third embodiment. It is a flowchart which shows the operation | movement procedure of the pulse control apparatus in 3rd Embodiment. It is a flowchart which shows the operation | movement procedure of the pulse control apparatus in 4th Embodiment.

DESCRIPTION OF SYMBOLS 1 Inkjet head 4 Flow path unit 8 Nozzle 10, 10a, 10b, 10c, 10d Pressure chamber 21 Actuator unit (main actuator block)
22 Cavity plate 23 Actuator plate (auxiliary actuator block)
34 First common electrode 35 First individual electrode 36 Main electrode region 37 Land (auxiliary electrode region)
38, 238 Second individual electrode 39 Connecting electrode 40 Second common electrode 41 Piezoelectric sheet (first piezoelectric sheet)
50 FPC (flexible flat cable)
61 Through-hole 62 Conductor 63, 263 Contact point 70 Head body 71 Base block 72 Holder 80 Driver IC
101 Inkjet printer (inkjet recording device)
200 Pulse control device (drive signal generator)
203 Signal generator 203a Discharge pulse generator (pulse generator)
203b Auxiliary drive signal generator (auxiliary drive signal generator)
204a Discharge pulse supply unit (pulse supply means)
204b Auxiliary drive signal supply unit (auxiliary drive signal supply means)

Claims (17)

A pressure chamber block composed of one or a plurality of sheet-like members, wherein a plurality of pressure chambers communicating with the nozzle are arranged along a plane;
A main actuator block fixed to one surface of the pressure chamber block to change the volume of the pressure chamber;
An auxiliary actuator block that is fixed to a surface opposite to the one surface of the pressure chamber block and changes a volume of the pressure chamber ;
A nozzle block fixed to the side opposite to the pressure chamber block with respect to the auxiliary actuator block and having the nozzle formed thereon,
The main actuator block is
A plurality of first individual electrodes arranged at positions respectively facing the plurality of pressure chambers;
A first common electrode provided across the plurality of pressure chambers;
A first piezoelectric sheet sandwiched between the first common electrode and the first individual electrode;
The auxiliary actuator block is
A plurality of second individual electrodes disposed at positions respectively facing the plurality of pressure chambers ;
A second common electrode provided over the pressure chamber of the multiple,
A plurality of piezoelectric sheets stacked together including a second piezoelectric sheet sandwiched between the second common electrode and the second individual electrode ;
An ink-jet head, wherein the second piezoelectric sheet that is displaced by a piezoelectric effect when an electric field is applied is sandwiched between the piezoelectric sheets that are not affected by the electric field and that do not spontaneously displace . The main actuator block includes a contact portion that is electrically insulated from the first individual electrode and the first common electrode and disposed adjacent to the first individual electrode;
2. The inkjet head according to claim 1, wherein the second individual electrode is electrically connected to the contact portion through a through-hole penetrating the pressure chamber block. The pressure chamber has a plane shape of a parallelogram having two acute corners or a parallelogram with rounded corners;
The first individual electrode is drawn from a main electrode region having a similar shape to the pressure chamber disposed at a position facing the pressure chamber, and one acute angle portion in the longitudinal direction of the main electrode region, and is adjacent to the acute angle portion. And an auxiliary electrode region arranged as
The first individual electrode and the pressure chamber are arranged in a matrix so that the auxiliary electrode region is located between two other main electrode regions,
The inkjet head according to claim 2, wherein the contact portion is disposed on the opposite side of the auxiliary electrode region with respect to the main electrode region. The second individual electrode is
A main electrode region having a shape similar to that of the pressure chamber disposed at a position facing the pressure chamber;
It is composed of a lead portion drawn from the other acute angle portion with respect to the longitudinal direction of the main electrode region,
The inkjet head according to claim 3, wherein the leading end portion of the drawer portion and the contact portion are electrically joined. The inkjet head according to claim 1, wherein the plurality of adjacent second individual electrodes are electrically connected to each other by a connection electrode. The main actuator block is composed of the first individual electrode, the first common electrode, and the first piezoelectric sheet, and the polarization is applied when an external electric field is applied in the polarization direction of the main actuator block. The volume of the pressure chamber is changed by utilizing the expansion and contraction of the first piezoelectric sheet in a direction crossing the direction, and the first piezoelectric sheet side is opposite to the first piezoelectric sheet side with respect to the first individual electrode. inkjet head according to any one of claims 1 to 5 is intended to restrict the expansion and contraction of the first piezoelectric sheet, characterized by the absence. The nozzle block has an ink ejection region in which a plurality of the nozzles respectively corresponding to the pressure chambers are arranged on a surface opposite to the pressure block.
The auxiliary actuator block in which a hole connecting the pressure chamber and the nozzle is formed, the pressure chamber block, and the nozzle block, a flow path unit in which an ink flow path having the nozzle at one end is formed. The inkjet head according to any one of claims 1 to 6 , wherein the inkjet head is configured. An inkjet head that ejects ink drops;
An inkjet recording apparatus comprising: a drive signal generation device configured to generate a drive signal supplied to the inkjet head;
The inkjet head is
A pressure chamber block composed of one or a plurality of sheet-like members, wherein a plurality of pressure chambers communicating with the nozzle are arranged along a plane;
A main actuator block fixed to one surface of the pressure chamber block to change the volume of the pressure chamber;
An auxiliary actuator block that is fixed to a surface opposite to the one surface of the pressure chamber block and changes a volume of the pressure chamber;
The main actuator block is
A plurality of first individual electrodes arranged at positions facing the plurality of pressure chambers;
A first common electrode provided across the plurality of pressure chambers;
A first piezoelectric sheet sandwiched between the first common electrode and the first individual electrode;
The auxiliary actuator block is
A plurality of second individual electrodes disposed at positions facing the plurality of pressure chambers;
A second common electrode provided across the plurality of pressure chambers;
A second piezoelectric sheet sandwiched between the second common electrode and the second individual electrode;
The drive signal generator is
Pulse generating means for generating a pulse train signal supplied to the first individual electrode;
Auxiliary drive signal generation that generates an auxiliary drive signal that is supplied to the second individual electrode, has an amplitude that does not cause ink ejection from the nozzles alone, and has a higher frequency than the pulse train signal. Means,
Pulse supply means for supplying the pulse train signal to the first individual electrodes related to the nozzles to eject ink droplets based on image data;
An auxiliary drive signal supply means for supplying the auxiliary drive signal to at least the second individual electrode related to the nozzle that should eject ink droplets ;
The supply of the auxiliary drive signal generated by the auxiliary drive signal generation unit to the second individual electrode and the supply of the pulse train signal generated by the pulse generation unit to the first individual electrode reduce the volume of the pressure chamber. An ink jet recording apparatus characterized by being synchronized so as to coincide with each other at a decrease timing . Wherein the frequency of the auxiliary drive signal auxiliary driving signal generating means generates is claimed in claim 8, wherein the n times the frequency of the pulse train signal pulse generating means generates (n is a natural number of 2 or more) is Inkjet recording apparatus. 10. The ink jet recording apparatus according to claim 8 , wherein the pulse train signal generated by the pulse generation unit includes a pulse having an amplitude that causes ink ejection from the nozzle independently. The inkjet recording apparatus according to any one of claims 8 to 10, wherein the second individual electrodes of the auxiliary actuator block are electrically connected to each other. The inkjet recording apparatus according to claim 8 , wherein the second individual electrodes of the auxiliary actuator block are electrically independent from each other.   The auxiliary drive signal generated by the auxiliary drive signal generating means includes a plurality of the adjacent adjacent second electrodes that share the pressure chamber with the first individual electrode supplied with the pulse train signal generated by the pulse generating means. The inkjet recording apparatus according to claim 12, wherein the inkjet recording apparatus is supplied to at least one of the second individual electrodes. The planar shape of the pressure chamber is a parallelogram having two acute angles or a parallelogram with rounded corners,
The first individual electrode is disposed in a direction facing the pressure chamber, and a main electrode region that is connected to the main electrode region and is directed from the main electrode region toward one acute angle portion of the pressure chamber. An auxiliary electrode region, and
The first individual electrode and the pressure chamber are arranged in a matrix so that the auxiliary electrode region is located between the main electrode regions of the other two first individual electrodes,
The auxiliary drive signal generated by the auxiliary drive signal generation unit is adjacent to an acute angle portion or a corner portion on the opposite side of the auxiliary electrode region of the first individual electrode to which the pulse train signal generated by the pulse generation unit is supplied. The inkjet recording apparatus according to claim 13, wherein the inkjet recording apparatus is supplied to the second individual electrode sharing the pressure chamber with the two first individual electrodes. The auxiliary drive signal auxiliary driving signal generating means generates the ink jet recording apparatus according to any one of claims 12 to 14, characterized in that it is supplied to all of the second individual electrodes. A nozzle block fixed to the side opposite to the pressure chamber block with respect to the auxiliary actuator block and having the nozzle formed thereon;
The auxiliary actuator block formed with a hole connecting the pressure chamber and the nozzle, the pressure chamber block, and the nozzle block constitute a flow path unit,
The said flow path unit, a common ink chamber communicating with a plurality of the pressure chambers, and a plurality of individual ink flow passages leading to the nozzle from an outlet of the common ink chamber through the pressure chamber has been made form ,
It said pulse said column signal is supplied first the pressure chamber facing the individual electrodes adjacent the outlet of the common ink chamber communicating with said second opposed to the pressure chamber communicating with a different outlet with the outlet The ink jet recording apparatus according to claim 12, wherein at least one individual electrode is supplied with an auxiliary drive signal. The auxiliary drive signal generating means generates a sine wave signal,
17. The inkjet recording apparatus according to claim 12, wherein a width of a pulse constituting the pulse train signal corresponds to an odd multiple of a half wavelength of the sine wave signal.

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