JP2009233941A - Liquid discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid discharge head can perform a satisfactory printing even when being driven at the frequency of ≥20 kHz. <P>SOLUTION: The liquid discharge head includes: a channel member having a lower-face side manifold in a body, which is a flat plate, a plurality of liquid discharge holes and liquid pressure chambers, wherein the manifold and the liquid pressure chambers are connect by disposing individual supply channels and diaphragms in that order from the manifold side; and a plurality of displacing elements. The individual supply channels are connected to the manifold in the lengthwise direction of the body at pitches the average of which is 170 μm or less. Some of the liquid pressure chambers are superposed on the manifold, as viewed from above. A distance between the manifold and each of the liquid pressure chambers superposed on the manifold is 700 to 1,000 μm. The distance from the lower face of the lquid pressure chamber to the upper face of the manifold is 270 to 600 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid discharge head, and more particularly to a liquid discharge head suitably used for an ink jet printer used for recording characters and images.

  In recent years, recording apparatuses using an inkjet recording method, such as inkjet printers and inkjet plotters, are not only printers for general consumers, but also, for example, formation of electronic circuits, manufacture of color filters for liquid crystal displays, manufacture of organic EL displays It is also widely used for industrial applications.

  In such an ink jet recording apparatus, a liquid discharge head for discharging a liquid is mounted as a print head. This type of print head includes a heater as a pressurizing unit in an ink flow path filled with ink, heats and boiles the ink with the heater, pressurizes the ink with bubbles generated in the ink flow path, A thermal head system that ejects ink as droplets from the ink ejection holes, and a part of the wall of the ink channel filled with ink is bent and displaced by a displacement element, and the ink in the ink channel is mechanically pressurized, and the ink A piezoelectric method for discharging liquid droplets from discharge holes is generally known.

  In addition, such a liquid discharge head includes a serial type that performs recording while moving the head in a direction (main scanning direction) orthogonal to the conveyance direction (sub-scanning direction) of the recording medium, and a recording medium in the main scanning direction. There is a line type in which recording is performed on a recording medium conveyed in the sub-scanning direction with a long head fixed. The line type has the advantage that high-speed recording is possible because there is no need to move the head as in the serial type.

  In order to print droplets at a high density regardless of whether the liquid ejection head is of a serial type or a line type, the density of the liquid ejection holes for ejecting the droplets formed in the liquid ejection head is increased. There is a need.

Therefore, a flow path member having a liquid discharge hole connecting the print output head to the manifold and the plurality of liquid pressurizing chambers respectively, and a plurality of displacement elements provided so as to cover the liquid pressurizing chambers, respectively. A technique is known in which an actuator substrate is stacked and configured (see, for example, Patent Document 1). In this liquid ejection head, the liquid pressurizing chamber connected to each liquid ejection hole is displaced by a displacement element provided so as to cover the chamber, thereby ejecting ink from each liquid ejection hole and 600 dpi in the sub-scanning direction. It is possible to print at a resolution of.
JP 2003-305852 A

  However, in the liquid discharge head described in Patent Document 1, if the drive frequency of the drive signal given to the displacement element is about 20 kHz or less, the liquid discharge characteristics of each liquid discharge hole are small and printing is performed in a good state. Although it is possible, if the drive frequency is further increased in order to increase the printing speed or the like, there is a problem that the variation in the liquid ejection characteristics of the respective liquid ejection holes increases and the printing state deteriorates.

Specifically, when the liquid discharge hole is one end and the flow path connecting the manifold through the liquid pressurizing chamber, the squeezing, and the individual supply flow path in this order is an individual flow path, the manifold has many individual flow paths. When liquid droplets are ejected from many liquid ejection holes, such as when the entire printable range is printed solidly in a liquid ejection device connected at high density, the displacement of each displacement element is the liquid in the flow path, or The liquid in the manifold may be vibrated through the flow path member. Then, this vibration is transmitted to the liquid pressurizing chamber at the position where it overlaps with the manifold, and the liquid discharge characteristics of the liquid discharge holes connected to the liquid pressurizing chamber may fluctuate. Where
This variation in the liquid ejection characteristics is, for example, a variation in the liquid ejection speed, and the position of the droplets that land on the print medium is shifted due to the variation in the liquid ejection speed.

  Accordingly, an object of the present invention is to provide a liquid discharge head that can be printed well even when driven at a driving frequency higher than 20 kHz.

  The liquid discharge head according to the present invention includes a manifold to which liquid is supplied from the outside on a lower surface side in a flat plate-like main body, and includes a plurality of liquid pressurizing chambers on the upper surface in the main body. The liquid pressurizing chamber is connected to the manifold side by arranging individual supply flow paths and throttles in this order, and a plurality of liquid discharge chambers connected to the lower surface of the main body with the plurality of liquid pressurizing chambers, respectively. A liquid discharge head comprising a flow path member having a hole and a plurality of displacement elements that respectively pressurize a plurality of liquids in the liquid pressurizing chamber, wherein the plurality of individual supply flow paths are arranged in a longitudinal direction of the main body. Are connected to the manifold at an average pitch of 170 μm or less, and some liquid pressurizing chambers of the plurality of liquid pressurizing chambers overlap the manifold as viewed from the upper surface side. And the distance from the lower surface of the liquid pressurizing chamber arranged to overlap the manifold to the lower surface of the manifold is 700 to 1000 μm, and from the lower surface of the liquid pressurizing chamber arranged to overlap the manifold. The distance to the upper surface of the manifold is 270 to 600 μm.

  According to the liquid discharge head of the present invention, a flat plate-like lower surface in the main body is provided with a manifold to which liquid is supplied from the outside, and an upper surface in the main body is provided with a plurality of liquid pressurizing chambers. The plurality of liquid pressurizing chambers are connected by arranging individual supply flow paths and squeezes in this order from the manifold side, and a plurality of liquid pressurizing chambers respectively connected to the lower surface of the main body. A liquid discharge head comprising: a flow path member having a liquid discharge hole; and a plurality of displacement elements that pressurize the liquid in each of the plurality of liquid pressurizing chambers, wherein the plurality of individual supply flow paths are longitudinally of the main body. The liquid pressure chambers are connected to the manifold at an average pitch of 170 μm or less along the direction, and some of the plurality of liquid pressure chambers overlap with the manifold as viewed from the upper surface side. And the distance from the lower surface of the liquid pressurizing chamber disposed so as to overlap the manifold to the lower surface of the manifold is 700 to 1000 μm, and the liquid pressurizing chamber disposed so as to overlap the manifold. Since the distance from the lower surface to the upper surface of the manifold is 270 to 600 μm, even when many displacement elements are displaced at high speed, the liquid overlapping the manifold when viewed from the upper surface side with the manifold. Since the propagation of vibration between the pressurizing chamber is reduced, the fluctuation of the liquid discharge characteristic from the liquid discharge hole is reduced due to the difference in the liquid discharge state from other surrounding liquid discharge holes.

  FIG. 1 is a schematic configuration diagram of a color inkjet printer including a liquid discharge head according to an embodiment of the present invention. This color inkjet printer 1 (hereinafter referred to as printer 1) has four liquid ejection heads 2. These liquid discharge heads 2 are arranged along the conveyance direction of the printing paper P and are fixed to the printer 1. The liquid discharge head 2 has an elongated shape in a direction from the front to the back in FIG.

  In the printer 1, a paper feed unit 114, a transport unit 120, and a paper receiver 116 are sequentially provided along the transport path of the printing paper P. In addition, the printer 1 is provided with a control unit 100 for controlling the operation of each unit of the printer 1 such as the liquid discharge head 2 and the paper feeding unit 114.

  The paper supply unit 114 includes a paper storage case 115 that can store a plurality of printing papers P, and a paper supply roller 145. The paper feed roller 145 can send out the uppermost print paper P among the print papers P stacked and stored in the paper storage case 115 one by one.

  Between the paper feed unit 114 and the transport unit 120, two pairs of feed rollers 118a and 118b and 119a and 119b are arranged along the transport path of the printing paper P. The printing paper P sent out from the paper supply unit 114 is guided by these feed rollers and further sent out to the transport unit 120.

  The transport unit 120 includes an endless transport belt 111 and two belt rollers 106 and 107. The conveyor belt 111 is wound around belt rollers 106 and 107. The conveyor belt 111 is adjusted to such a length that it is stretched with a predetermined tension when it is wound around two belt rollers. Thus, the conveyor belt 111 is stretched without slack along two parallel planes each including a common tangent line of the two belt rollers. Of these two planes, the plane closer to the liquid ejection head 2 is a transport surface 127 that transports the printing paper P.

  As shown in FIG. 1, a conveyance motor 174 is connected to the belt roller 106. The transport motor 174 can rotate the belt roller 106 in the direction of arrow A. The belt roller 107 can rotate in conjunction with the transport belt 111. Therefore, the conveyance belt 111 moves along the direction of arrow A by driving the conveyance motor 174 and rotating the belt roller 106.

  In the vicinity of the belt roller 107, a nip roller 138 and a nip receiving roller 139 are arranged so as to sandwich the conveyance belt 111. The nip roller 138 is urged downward by a spring (not shown). A nip receiving roller 139 below the nip roller 138 receives the nip roller 138 biased downward via the conveying belt 111. The two nip rollers are rotatably installed and rotate in conjunction with the conveyance belt 111.

  The printing paper P sent out from the paper supply unit 114 to the transport unit 120 is sandwiched between the nip roller 138 and the transport belt 111. As a result, the printing paper P is pressed against the transport surface 127 of the transport belt 111 and is fixed on the transport surface 127. The printing paper P is transported in the direction in which the liquid ejection head 2 is installed according to the rotation of the transport belt 111. The outer peripheral surface 113 of the conveyor belt 111 may be treated with adhesive silicon rubber. Thereby, the printing paper P can be securely fixed to the transport surface 127.

  The four liquid discharge heads 2 are arranged close to each other along the conveyance direction by the conveyance belt 111. Each liquid discharge head 2 has a head body 13 at the lower end. A large number of liquid discharge ports 8 for discharging liquid are provided on the lower surface of the head body 13 (see FIG. 3).

  A liquid (ink) of the same color is ejected from a liquid ejection port 8 provided in one liquid ejection head 2. The colors of the liquid ejected from each liquid ejection head 2 are magenta (M), yellow (Y), cyan (C), and black (K), respectively. Each liquid ejection head 2 is disposed with a slight gap between the lower surface of the head body 13 and the transport surface 127 of the transport belt 111.

  The printing paper P transported by the transport belt 111 passes through the gap between the liquid ejection head 2 and the transport belt 111. At that time, liquid is discharged from the head main body 13 constituting the liquid discharge head 2 toward the upper surface of the printing paper P. As a result, a color image based on the image data stored by the control unit 100 is formed on the upper surface of the printing paper P.

A separation plate 140 and two pairs of feed rollers 121a and 121b and 122a and 122b are arranged between the transport unit 120 and the paper receiver 116.
The printing paper P on which the color image is printed is conveyed to the peeling plate 140 by the conveying belt 111. At this time, the printing paper P is peeled from the transport surface 127 by the right end of the peeling plate 140. Then, the printing paper P is sent out to the paper receiving unit 116 by the feed rollers 121a to 122b. In this way, the printed printing paper P is sequentially sent to the paper receiving unit 116 and stacked on the paper receiving unit 116.

  Note that a paper surface sensor 133 is installed between the liquid ejection head 2 and the nip roller 138 that are the most upstream in the transport direction of the printing paper P. The paper surface sensor 133 includes a light emitting element and a light receiving element, and can detect the leading end position of the printing paper P on the transport path. The detection result by the paper surface sensor 133 is sent to the control unit 100. The control unit 100 can control the liquid ejection head 2, the conveyance motor 174, and the like so that the conveyance of the printing paper P and the printing of the image are synchronized based on the detection result sent from the paper surface sensor 133.

  Next, the head main body 13 constituting the liquid discharge head of the present invention will be described. FIG. 2 is a top view showing the head main body 13 shown in FIG. FIG. 3 is an enlarged top view of a region surrounded by the alternate long and short dash line in FIG. 2 and is a part of the head main body 13. For convenience of explanation, the piezoelectric actuator substrate 21 is shown by a two-dot chain line in FIG. In addition, the squeezing 12 and the liquid discharge port 8 that are formed inside or on the lower surface of the flow path member 4 that should originally be indicated by a broken line are indicated by solid lines. 4 is a longitudinal sectional view taken along line IV-IV in FIG.

  The head body 13 includes a flat plate-like channel member 4 and a piezoelectric actuator substrate 21 stacked on the channel member 4. The piezoelectric actuator substrate 21 has a trapezoidal shape, and is disposed on the upper surface of the flow path member 4 so that a pair of parallel opposing sides of the trapezoid is parallel to the longitudinal direction of the flow path member 4. In addition, two piezoelectric actuator substrates 21 are arranged on the flow path member 4 as a whole in a zigzag manner, two along each of the two virtual straight lines parallel to the longitudinal direction of the flow path member 4. Yes. The oblique sides of the piezoelectric actuator substrates 21 adjacent on the flow path member 4 partially overlap in the width direction of the flow path member 4.

  A manifold 5 that is a part of the liquid flow path is formed inside the flow path member 4. The manifold 5 has an elongated shape extending along the longitudinal direction of the flow path member 4, and an opening 5 b of the manifold 5 is formed on the upper surface of the flow path member 4. A total of ten openings 5 b are formed along each of two straight lines (imaginary lines) parallel to the longitudinal direction of the flow path member 4. The opening 5b is formed at a position that avoids a region where the four piezoelectric actuator substrates 21 are disposed. The manifold 5 is supplied with liquid from a liquid tank (not shown) through the opening 5b.

  A plurality of manifolds 5 formed in the flow path member 4 are branched (the manifold 5 at the branched portion may be referred to as a sub-manifold 5a). The manifold 5 connected to the opening 5 b extends along the oblique side of the piezoelectric actuator substrate 21 and is disposed so as to intersect with the longitudinal direction of the flow path member 4. In the region sandwiched between the two piezoelectric actuator substrates 21, one manifold 5 is shared by the adjacent piezoelectric actuator substrates 21, and the sub-manifold 5 a is branched from both sides of the manifold 5. These sub-manifolds 5 a extend in the longitudinal direction of the head main body 13 adjacent to each other in a region facing the piezoelectric actuator substrates 21 inside the flow path member 4.

  The flow path member 4 has a liquid pressurizing chamber group 9 in which a plurality of liquid pressurizing chambers 10 are formed in a matrix (that is, two-dimensionally and regularly). The liquid pressurizing chamber 10 is a hollow region having a substantially rhombic planar shape with rounded corners. The liquid pressurizing chamber 10 is formed so as to open on the upper surface of the flow path member 4. These liquid pressurizing chambers 10 are arranged over almost the entire surface of the upper surface of the flow path member 4 facing the piezoelectric actuator substrate 21. Accordingly, each liquid pressurizing chamber group 9 formed by these liquid pressurizing chambers 10 occupies a region having almost the same size and shape as the piezoelectric actuator substrate 21. Further, the opening of each liquid pressurizing chamber 10 is closed by adhering the piezoelectric actuator substrate 21 to the upper surface of the flow path member 4.

  In the present embodiment, as shown in FIG. 3, the manifold 5 branches into four rows of sub-manifolds 5a arranged in parallel to each other in the short direction of the flow path member 4, and is connected to each sub-manifold 5a. The liquid pressurizing chambers 10 form a row of the liquid pressurizing chambers 10 arranged at equal intervals in the longitudinal direction of the flow path member 4, and the four rows are arranged in parallel to each other in the short side direction. Two rows of liquid pressurizing chambers 10 connected to the sub-manifold 5a are arranged on both sides of the sub-manifold 5a. The two rows of liquid pressurization chambers 10 in which the liquid pressurization chambers 10 near the submanifold 5a are arranged overlap with the submanifold 5a when viewed from the upper surface side (that is, the liquid pressurization chambers 10 in that row are in the liquid pressurization chamber 10). Pressure chamber 10a). The two rows of liquid pressurization chambers 10 in which the liquid pressurization chambers 10 arranged far from the submanifold 5a are not overlapped with the submanifold 5a when viewed from the upper surface side (that is, the liquid pressurization chambers 10 in that row are not filled with liquid. Pressure chamber 10b).

  As a whole, the liquid pressurizing chambers 10 connected from the manifold 5 constitute rows of the liquid pressurizing chambers 10 arranged in the longitudinal direction of the flow path member 4 at equal intervals, and the rows are 16 rows parallel to each other in the short direction. It is arranged. The number of liquid pressurizing chambers 10 included in each liquid pressurizing chamber row is arranged so as to gradually decrease from the long side toward the short side corresponding to the outer shape of the displacement element 50. The liquid discharge holes 8 are also arranged in the same manner. As a result, it is possible to form an image with a resolution of 600 dpi in the longitudinal direction as a whole. That is, the individual flow paths 32 are connected to each sub-manifold 5a at a pitch corresponding to 150 dpi on average. This is because the individual flow paths 32 connected to the sub-manifolds 5a are not necessarily connected at an equal pitch when the 600 dpi liquid discharge holes 8 are divided and connected to the four sub-manifolds 5a. That is, the individual flow paths 32 are formed at an average pitch of 170 μm (25.4 mm / 150 = 169 μm pitch if 150 dpi) in the extending direction of 5a, that is, the sub-scanning direction.

  The liquid pressurization chamber 10 includes a liquid pressurization chamber 10a that overlaps the sub-manifold 5a and a liquid pressurization chamber 10b that does not overlap the sub-manifold 5a when viewed from the upper surface side of the flow path member 4. By adopting such a structure, the cross-sectional area perpendicular to the liquid moving direction of the sub-manifold 5a can be widened so that a large amount of liquid can be supplied, and the density of the liquid pressurizing chamber 10 can be increased. Can do.

  Individual electrodes 35 as described below are formed at positions facing the respective liquid pressurizing chambers 10 on the upper surface of the piezoelectric actuator substrate 21. The individual electrode 35 is slightly smaller than the liquid pressurizing chamber 10, has a shape substantially similar to the liquid pressurizing chamber 10, and fits in a region facing the liquid pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 21. Is arranged.

  A large number of liquid discharge ports 8 are formed on the lower surface of the flow path member 4. These liquid discharge ports 8 are arranged at a position avoiding a region facing the sub-manifold 5 a arranged on the lower surface side of the flow path member 4. Further, these liquid discharge ports 8 are disposed in a region facing the piezoelectric actuator substrate 21 on the lower surface side of the flow path member 4. The liquid discharge ports 8 in each region are arranged at equal intervals along a plurality of straight lines parallel to the longitudinal direction of the flow path member 4.

  These liquid discharge ports 8 are printed on a virtual straight line parallel to the longitudinal direction of the flow path member 4 by projecting points where the formation positions of the liquid discharge ports 8 are projected from a direction perpendicular to the virtual straight line. They are formed at positions that are arranged at regular intervals at intervals corresponding to the resolution. As a result, the liquid discharge head 2 can print without interruption at intervals corresponding to the print resolution over almost the entire region in the longitudinal direction of the region where the liquid discharge port 8 is formed in the flow path member 4. Yes.

  A large number of apertures 12 are formed inside the flow path member 4. These throttles 12 are arranged in a region facing the liquid pressurizing chamber group 9. The aperture 12 of the present embodiment extends along one direction parallel to the horizontal plane. One end of the squeezing 12 is connected to the sub-manifold 5a via the individual supply channel 6 described later. Further, the other end of the squeezing 12 is connected to the liquid pressurizing chamber 10.

  The flow path member 4 included in the head body 13 has a stacked structure in which a plurality of plates are stacked. These plates are a cavity plate 22, a base plate 23, an aperture (squeezing) plate 24, supply plates 25 and 26, manifold plates 27, 28 and 29, a cover plate 30 and a nozzle plate 31 in order from the upper surface of the flow path member 4. is there. A number of holes are formed in these plates. Each plate is aligned and laminated so that these holes communicate with each other to form the individual flow path 32 and the sub-manifold 5a. As shown in FIG. 4, the head main body 13 has a liquid pressurizing chamber 10a on the upper surface of the flow path member 4, the sub-manifold 5a on the inner lower surface side, and the liquid discharge port 8 on the lower surface. Each part constituting the path 32 is disposed close to each other at different positions, and the sub manifold 5a and the liquid discharge port 8 are connected via the liquid pressurizing chamber 10a.

  The holes formed in each plate will be described. These holes include the following. First, the liquid pressurizing chamber 10 formed in the cavity plate 22. Second, there is a communication hole that forms a flow path that connects from one end of the liquid pressurizing chamber 10 to the sub-manifold 5a. This communication hole is formed in each plate from the base plate 23 (specifically, the inlet of the liquid pressurizing chamber 10) to the supply plate 25 (specifically, the outlet of the sub manifold 5a). The communication hole includes the aperture 12 formed in the aperture plate 24 and the individual supply flow path 6 formed in the supply plates 25 and 26.

  Third, there is a communication hole that constitutes a flow channel that communicates from the other end of the liquid pressurizing chamber 10 to the liquid discharge port 8, and this communication hole is referred to as a descender (partial flow channel) in the following description. . It is formed on each plate from the descender and base plate 23 (specifically, the outlet of the liquid pressurizing chamber 10) to the nozzle plate 31 (specifically, the liquid discharge port 8). Fourthly, there is a communication hole constituting the sub-manifold 5a. The communication holes are formed in the manifold plates 27-30.

  Such communication holes are connected to each other to form an individual flow path 32 extending from the liquid inlet from the sub-manifold 5a (the outlet of the sub-manifold 5a) to the liquid discharge port 8. The liquid supplied to the sub-manifold 5a is discharged from the liquid discharge port 8 through the following path. First, from the sub-manifold 5a, it passes through the individual supply flow path 6 and reaches one end of the aperture 12. Next, it proceeds horizontally along the extending direction of the aperture 12 and reaches the other end of the aperture 12. From there, it reaches one end of the liquid pressurizing chamber 10 upward. Further, the liquid pressurizing chamber 10 proceeds horizontally along the extending direction of the liquid pressurizing chamber 10 and reaches the other end of the liquid pressurizing chamber 10. While moving little by little in the horizontal direction from there, it proceeds mainly downward and proceeds to the liquid discharge port 8 opened on the lower surface.

  In the liquid discharge head having such a cross-sectional structure, when the entire printable range is printed solid, that is, when a large amount of liquid droplets are discharged from the most liquid discharge holes 8 as much as possible (hereinafter, all Most of the pressure wave applied to the liquid in the liquid pressurizing chamber 10 by the displacement element 50 is reflected by the squeeze 12, but a part of the pressure wave is squeezed 12. Over the individual supply flow path 6 and reach the sub-manifold 5a. As described above, since a large number of individual flow paths 32 are connected to the sub-manifold 5a with high density, the liquid in the sub-manifold 5a vibrates in a complicated manner due to pressure waves transmitted from the large number of individual flow paths 32. Will do.

  When the drive frequency is low, the vibration is attenuated while not being driven. Therefore, the influence of the vibration on the discharge characteristics from each liquid discharge hole 8 is relatively small. When the drive frequency increases and exceeds 20 kHz, the liquid is discharged from the liquid discharge hole 8 close to the sub-manifold 5a, that is, the liquid discharge hole 8 connected to the liquid pressurizing chamber 10a overlapping the sub-manifold 5a when viewed from the upper surface side. The phenomenon that the speed becomes faster appears. FIG. 7A shows a liquid discharge head having a structure in which a part of the liquid pressurizing chambers 10 are arranged so as to overlap with the sub-manifold 5a when viewed from the upper surface side, and the liquid in the liquid discharge hole 8 close to the sub-manifold 5a. The discharge speed is measured by changing the drive frequency. Up to a drive frequency of 20 kHz, the discharge speed is almost constant regardless of the drive frequency, but when it exceeds 20 kHz, the discharge speed increases. This is because the vibration of the sub-manifold 5a is transmitted to the liquid pressurizing chamber 10a via the channel member between the sub-manifold 5a and the liquid pressurizing chamber 10a, or the vibration of the sub-manifold 5a is transmitted to the individual supply channel 6 and The cause is considered to be transmitted to the liquid pressurizing chamber 10a through the liquid inside the squeezing 12.

  The effect of increasing the drive frequency is the liquid discharge speed from the liquid discharge hole 8 that is connected to the liquid discharge hole 8 far from the sub manifold 5a, that is, the liquid pressurizing chamber 10b that does not overlap the sub manifold 5a when viewed from the upper surface side. Is less. Since there is a difference in the liquid discharge speed due to the liquid discharge holes 8, the image quality such as an image to be printed may be deteriorated.

  Therefore, the distance a from the lower surface of the liquid pressurizing chamber 10a overlapping the manifold 5a when viewed from the upper surface side to the lower surface of the submanifold 5a is set to 700 to 1000 μm, and from the lower surface of the liquid pressurizing chamber 10a to the upper surface of the submanifold 5a. By setting the distance b to 270 to 600 μm, it is possible to reduce variations in the liquid discharge speed even when the driving frequency is as high as 30 kHz. By setting the distance a to 1000 μm or less, the length of the descender can be shortened, and the complicated resonance in the individual flow path generated by the squeezing, the liquid pressurizing chamber, the displacement element, and the descender flow path shape can be prevented. Therefore, the influence on the formation state of the meniscus formed in the vicinity of the liquid discharge hole 8 is reduced, the shape stability of the discharged droplet is increased, and stable discharge can be obtained. When the distance a is 700 μm or more, the distance b can be increased, and the transmission of vibration through the flow path member between the liquid pressurizing chamber 10a and the sub manifold 5a can be suppressed. When the distance b is 270 μm or more, it is possible to suppress the transmission of vibration through the flow path member between the liquid pressurizing chamber 10a and the sub manifold 5a. When the distance b between the liquid pressurizing chamber 10a and the sub-manifold 5a is 600 μm or less, the distance a between the sub-manifold 5a and the inner surface on the lower surface side can be reduced.

  The thickness c (= a−b) of the sub-manifold 5a is preferably 150 to 500 μm. When the thickness c is 150 μm or more, even when the liquid is discharged from all the liquid discharge holes 8, the liquid can be sufficiently supplied, and the amount of liquid in the sub manifold 5a is too small, so that each displacement element It is possible to suppress the vibration of the liquid in the sub-manifold 5a from being increased by the pressure wave generated by 50. When the thickness c is 500 μm or less, the distance a from the lower surface of the liquid pressurizing chamber 10a to the lower surface of the sub manifold 5a can be reduced.

  As shown in FIG. 4, the piezoelectric actuator substrate 21 has a laminated structure including two piezoelectric ceramic layers 21a and 21b. Each of these piezoelectric ceramic layers 21a and 21b has a thickness of about 20 μm. The total thickness of the piezoelectric actuator substrate 21 is about 40 μm. Each of the piezoelectric ceramic layers 21a and 21b extends so as to straddle the plurality of liquid pressurizing chambers 10 (see FIG. 3). The piezoelectric ceramic layers 21a and 21b are made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity.

  The piezoelectric actuator substrate 21 has a common electrode 34 made of a metal material such as Ag—Pd and an individual electrode 35 made of a metal material such as Au. As described above, the individual electrode 35 is disposed at a position facing the liquid pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 21. One end of the individual electrode 35 is drawn out of a region facing the liquid pressurizing chamber 10 to form a connection electrode 36. The connection electrode 36 is made of, for example, gold containing glass frit, and has a convex shape with a thickness of about 15 μm. The connection electrode 36 is electrically joined to an electrode provided in an FPC (Flexible Printed Circuit) (not shown). Although details will be described later, a voltage pulse is supplied to the individual electrode 35 from the control unit 100 through the FPC.

  The common electrode 34 is formed over almost the entire surface in the area between the piezoelectric ceramic layer 21a and the piezoelectric ceramic layer 21b. That is, the common electrode 34 extends so as to cover all the liquid pressurizing chambers 10 in the region facing the piezoelectric actuator substrate 21. The thickness of the common electrode 34 is about 2 μm. The common electrode 34 is grounded in a region not shown, and is held at the ground potential. In the present embodiment, a surface electrode (not shown) different from the individual electrode 35 is formed on the piezoelectric ceramic layer 21b at a position avoiding the electrode group composed of the individual electrodes 35. The surface electrode is electrically connected to the common electrode 34 through a through-hole formed in the piezoelectric ceramic layer 21b, and is connected to another electrode on the FPC in the same manner as many individual electrodes 35. ing.

  As shown in FIG. 4, the common electrode 34 and the individual electrode 35 are arranged so as to sandwich only the uppermost piezoelectric ceramic layer 21b. A region sandwiched between the individual electrode 35 and the common electrode 34 in the piezoelectric ceramic layer is referred to as an active portion, and the piezoelectric ceramic in that portion is polarized. In the piezoelectric actuator substrate 21 of the present embodiment, only the uppermost piezoelectric ceramic layer 21b includes an active portion, and the piezoelectric ceramic 21a does not include an active portion and functions as a diaphragm. The piezoelectric actuator substrate 21 has a so-called unimorph type configuration.

  As will be described later, when a predetermined voltage pulse is selectively supplied to the individual electrode 35, pressure is applied to the liquid in the liquid pressurizing chamber 10 corresponding to the individual electrode 35. As a result, the liquid is discharged from the corresponding liquid discharge port 8 through the individual flow path 32. That is, the portion of the piezoelectric actuator substrate 21 facing each liquid pressurizing chamber 10 corresponds to an individual displacement element 50 (actuator) corresponding to each liquid pressurizing chamber 10 and the liquid discharge port 8. That is, in the laminate composed of two piezoelectric ceramic layers, the displacement element 50 having a unit structure as shown in FIG. 4 is provided immediately above the liquid pressurizing chamber 10 for each liquid pressurizing chamber 10. Are formed by a diaphragm 21a, a common electrode 34, a piezoelectric ceramic layer 21b, and individual electrodes 35, and the piezoelectric actuator substrate 21 includes a plurality of displacement elements 50. In the present embodiment, the amount of liquid ejected from the liquid ejection port 8 by one ejection operation is about 5 to 7 pL (picoliter).

  Next, the control of the piezoelectric actuator substrate 21 will be described. In order to control the piezoelectric actuator substrate 21, the printer 1 has a control unit 100 and a driver IC 80 (see FIG. 5). The printer 1 includes a CPU (Central Processing Unit) which is an arithmetic processing unit, a program executed by the CPU and a ROM (Read Only Memory) in which data used for the program is stored, and data temporarily when the program is executed. A control unit 100 having a RAM (Random Access Memory) for storing data and having the functions described below is constructed by these and other hardware.

  As illustrated in FIG. 5, the control unit 100 includes a print control unit 101 and an operation control unit 105. The print control unit 101 includes an image data storage unit 102, a waveform pattern storage unit 103, and a print signal generation unit 104. The image data storage unit 102 stores image data related to printing transmitted from the PC 133 or the like.

  The waveform pattern storage unit 103 stores waveform data corresponding to a plurality of ejection pulse train waveforms. Each ejection pulse train waveform corresponds to a basic waveform corresponding to the gradation of the image. By supplying a voltage pulse signal corresponding to such a waveform to the individual electrode 35 via the driver IC 80, an amount of liquid corresponding to each gradation or the like is ejected from the liquid ejection head 2.

  The print signal generation unit 104 generates serial print data based on the image data stored in the image data storage unit 102. Such print data is for sequentially supplying one of a plurality of ejection pulse train waveforms stored in the waveform pattern storage unit 103 to the individual electrodes 35, and each ejection electrode 35 is ejected at a predetermined timing. This is data instructing to supply a pulse train waveform. The print signal generation unit 104 generates print data corresponding to the timing, waveform, and individual electrodes corresponding to the image data based on the image data stored in the image data storage unit 102. Then, the print signal generation unit 104 outputs the generated print data to the driver IC 80.

  The driver IC 80 is provided for each piezoelectric actuator substrate 21 and includes a shift register, a multiplexer, and a drive buffer (both not shown).

  The shift register converts serial print data output from the print signal generation unit 104 into parallel data. That is, the shift register outputs individual data for the displacement elements 50 corresponding to the liquid pressurizing chambers 10 and the liquid discharge ports 8 in accordance with the print data instructions.

  The multiplexer selects an appropriate one from a plurality of ejection pulse train waveforms related to the waveform data supplied from the waveform pattern storage unit 103 to the driver IC 80 based on each data output from the shift register. Then, the multiplexer outputs the selected ejection pulse train waveform to the drive buffer.

  The drive buffer generates an ejection voltage pulse train signal having a predetermined level by amplifying the ejection pulse train waveform output from the multiplexer. The drive buffer supplies the ejection voltage pulse train signal to the individual electrode 35 corresponding to the displacement element 50 through the FPC.

  The discharge voltage pulse train signal and the change in potential at the individual electrode 35 that has been supplied with this signal are described.

  The voltage at each time included in the ejection voltage pulse train signal will be described. FIG. 6 shows an example of potential change in the individual electrode 35 to which the ejection voltage pulse train signal is supplied. A waveform 61 of the ejection voltage pulse train signal shown in FIG. 6 is an example of a waveform for ejecting one drop of liquid from the liquid ejection port 8.

Time t ₁ is the time when the ejection voltage pulse train signal starts to be supplied to the individual electrode 35. Time t ₁ is adjusted for a liquid ejection port 8 corresponding to the individual electrode 35 to the timing of ejecting the liquid. In the waveform 61 of the ejection voltage pulse train signal, the voltage is held at U ₀ (> 0) during the period up to time t ₁ and the period after time t ₄ . Then, the period from time t ₂ to time t ₃ the voltage is held at ground potential. Period from time t ₁ to time t _2, the potential of the individual electrode 35 is in a transient period from U ₀ until the ground potential. Further, the period from time t ₃ to time t ₄ is a transient period in which the potential of the individual electrode 35 changes from the ground potential to the U _0. As shown in FIG. 5, the displacement element 50 has the same configuration as the capacitor. Therefore, when the potential of the individual electrode 35 changes, the transient as described above corresponds to the charge / discharge of charges. A period arises.

  The following is a description of how the displacement element 50 is driven when the ejection voltage pulse train signal as described above is supplied to the individual electrode 35.

  In the piezoelectric actuator substrate 21 in the present embodiment, only the uppermost piezoelectric ceramic layer 21 b is polarized in the direction from the individual electrode 35 toward the common electrode 34. Therefore, when an electric field is applied to the piezoelectric ceramic layer 21b in the same direction as the polarization direction, specifically, in the direction from the individual electrode 35 toward the common electrode 34, by setting the individual electrode 35 to a potential different from that of the common electrode 34, The portion to which the electric field is applied, that is, the active portion tends to extend in the thickness direction, that is, the stacking direction. At this time, the active portion tends to shrink in a direction perpendicular to the stacking direction, that is, in the plane direction. In contrast, the diaphragm 21a is not polarized and does not spontaneously deform even when an electric field is applied.

  As described above, since a difference in distortion occurs between the piezoelectric ceramic layer 21b and the vibration plate 21a, the displacement element 50 as a whole is deformed so as to protrude toward the liquid pressurizing chamber 10 side (vibration plate 21a side). Unimorph deformation).

When the voltage pulse signal corresponding to the waveform 61 is supplied to the individual electrode 35, the displacement element 50 operates as follows. Since the potential of the individual electrode 35 is U ₀ during the period up to time t1, the displacement element 50 protrudes into the liquid pressurizing chamber 10 due to the unimorph deformation described above. In other words, the volume V ₁ of the liquid pressurizing chamber 10 at this time is smaller than when the potential of the individual electrode 35 is the ground potential. The state of the displacement element 50 at this time is referred to as a first state.

During the period from time t2 to time t3, since the potential of the individual electrode 35 is the ground potential, the electric field applied to the active portion in the piezoelectric ceramic layer 21b is released, and the unimorph deformation of the displacement element 50 is also released. At this time, the volume V ₂ of the liquid pressurizing chamber 10 is larger than the volume V ₁ . The state of the displacement element 50 at this time is referred to as a second state. As a result of the increase in the volume of the liquid pressurizing chamber 10 as described above, the liquid is sucked into the liquid pressurizing chamber 10 from the sub-manifold 5a.

  Since the potential of the individual electrode 35 is U0 during the period from time t4, the displacement element 50 returns to the first state again. In this manner, the displacement element 50 changes the liquid pressurizing chamber 10 from the second state to the first state, whereby pressure is applied to the liquid in the liquid pressurizing chamber 10. As a result, droplets are discharged from the liquid discharge port 8. The liquid droplets land on the printing surface of the printing paper P and form dots.

  Thus, in driving the displacement element 50 of the present embodiment, first, once the volume of the liquid pressurizing chamber 10 is increased and a negative pressure wave is generated in the liquid in the liquid pressurizing chamber 10, The pressure wave is reflected at the end of the liquid channel in the channel member 4 and returns as a positive pressure wave traveling toward the liquid discharge port 8. The volume of the liquid pressurizing chamber 10 is decreased again in view of the timing at which the positive pressure wave reaches the liquid pressurizing chamber 10. This is a so-called “fill before fire” technique.

As liquid ejection by pulling ejection as described above is performed, the voltage pulse having a waveform 61 of the liquid ejection pulse width T _{o (see} FIG. 6) is adjusted to AL (Acoustic Length). In the present embodiment, the liquid pressurizing chamber 10 is disposed in the vicinity of the center of the entire length of the individual flow path 32, and AL is a pressure wave generated in the liquid pressurizing chamber 10 from the squeezing 12 to the liquid discharge port 8. Is the length of time to propagate. According to this, the positive pressure wave reflected as described above and the positive pressure wave generated by the deformation of the displacement element 50 are superimposed, and a larger pressure is applied to the liquid. Therefore, the driving voltage of the displacement element 50 when discharging the same amount of liquid can be suppressed lower than when the liquid is pushed out by simply reducing the volume of the liquid pressurizing chamber 10 once. Therefore, the pulling method is advantageous in terms of high integration of the liquid pressurizing chamber 10, compactness of the liquid discharge head 2, and running cost when driving the liquid discharge head 2.

In the above description, the waveform 61 of the ejection voltage pulse train signal of the droplet forming one dot is a waveform that changes from U ₀ to the ground potential and returns to U _0. However, the waveform for forming one dot is as follows. , so as to eject a plurality of droplets may be a waveform the waveform back to U ₀ changes from U ₀ at the ground potential is included more. In this case, for example, by increasing the discharge speed of the liquid droplets discharged later than the discharge speed of the liquid droplets discharged first, a plurality of liquid droplets are combined during the flight, or the printing paper P approaches One dot is formed by landing on the portion. Further, in order to eject one droplet, the waveform back to U ₀ changes from U ₀ to the ground potential may be a plurality included waveform.

After forming one dot by a voltage pulse of waveform 61, to form the next dot after the predetermined time T _A has elapsed, given a voltage pulse waveform 62 in order to form the next dot, a droplet Discharge. Alternatively, if the portion corresponding to the next dot in the image to be printed is blank and it is not necessary to land the droplet, the droplet is not ejected by not applying a voltage pulse. Then, the shorter the predetermined time T _A, by increasing the relative moving speed of the print paper P and the liquid discharge head 2, increasing the amount of dots that can be formed per unit time, i.e., can be printed per unit time The area of the printing paper P can be increased. Reciprocal of the predetermined time T _A is the driving frequency.

  The above is a description of a preferred embodiment of the present invention. However, the present invention is not limited to the above-described embodiment, and various modifications can be made as long as the contents are described in the means for solving the problem. It can be changed. For example, the structure of the actuator and the shape of the individual flow path 3 can be changed as appropriate.

  The liquid discharge head 2 as described above is manufactured as follows, for example.

  A tape composed of a piezoelectric ceramic powder and an organic composition is formed by a general tape forming method such as a roll coater method or a slit coater method, and a plurality of green sheets that become piezoelectric ceramic layers 21a and 21b after firing are produced. . An electrode paste to be the common electrode 34 is formed on a part of the green sheet by a printing method or the like. Further, if necessary, a via hole is formed in a part of the green sheet, and a via conductor is inserted into the via hole.

  Next, each green sheet is laminated to produce a laminate, and pressure adhesion is performed. The laminated body after pressure contact is fired in a high-concentration oxygen atmosphere, and then the individual electrodes 25 are printed on the fired body surface using an organic gold paste, fired, and then the connection electrode 36 is printed using an Ag paste. And the piezoelectric actuator board | substrate 21 is produced by baking.

  Next, the flow path member 4 is produced by laminating plates 22 to 31 obtained by a rolling method or the like. Holes to be the manifold 5, the individual supply flow path 6, the liquid pressurizing chamber 10, the descender, and the like are processed in the plates 22 to 31 into a predetermined shape by etching.

  These plates 22 to 31 are preferably formed of at least one metal selected from the group consisting of Fe—Cr, Fe—Ni, and WC—TiC, particularly when ink is used as a liquid. Since it is desired to be made of a material having excellent corrosion resistance against ink, Fe-Cr is more preferable.

  The piezoelectric actuator 21 and the flow path member 4 can be laminated and bonded via an adhesive layer, for example. A well-known adhesive layer can be used as the adhesive layer. However, in order not to affect the piezoelectric actuator 21 and the flow path member 4, an epoxy resin, a phenol resin, or a polyphenylene ether having a thermosetting temperature of 100 to 150 ° C. It is preferable to use at least one thermosetting resin adhesive selected from the group of resins. By heating to the thermosetting temperature using such an adhesive layer, the piezoelectric actuator 21 and the flow path member 4 can be heat-bonded.

  Thereafter, in order to electrically connect the piezoelectric actuator upper 21 and an external circuit as necessary, an electrode such as FPC is joined to the connection electrode 63 to obtain the liquid ejection head 2.

  A liquid discharge head 2 having a changed flow path dimension in the flow path member 4 shown in FIGS. 2 to 4 is manufactured, and the liquid discharge head 2 is driven by changing a drive cycle to discharge liquid droplets. The effect on speed was investigated.

  The dimensions of the produced flow path are as follows. The sub-manifold 5a was 1.25 mm wide when viewed from the top. The individual supply channel 6 was a circular one having a diameter of 180 μm as viewed from the upper surface. The sub-manifold 5a is connected with individual supply channels 6 at a pitch of 169 μm (= 25.4 mm / 150) on the average in the sub-scanning direction, which is the longitudinal direction of the channel member, and the liquid discharge connected to this. The holes 8 are also formed at an average pitch of 169 μm in the sub-scanning direction, and an image having a resolution of 600 dpi can be printed in the sub-scanning direction by the entire liquid discharge head 2.

The squeezing 12 is a rectangle having a width of 43 μm and a length of 302 μm as viewed from above, and the thickness of the aperture plate 24 is 30 μm. A hole in the base plate 23 connecting one end of the squeezing 12 and one end of the liquid pressurizing chamber 10 was a circular shape having a diameter of 200 μm when viewed from above, and the thickness of the base plate 23 was 100 μm. The liquid pressurizing chamber 10 has an approximately rhombus shape with a rounded corner at an area of 0.31 mm ² as viewed from above, and the thickness of the cavity plate 22 is 50 μm. The descender has a circular shape with a diameter of 180 μm when viewed from the upper surface, and the length is a distance a + cover from the lower surface of the liquid pressurizing chamber 10a overlapping the manifold 5a when viewed from the upper surface side to be described later to the lower surface of the sub-manifold 5a. The thickness of the plate 30 was set to 30 μm.

The liquid discharge hole 8 has the vertical cross-sectional shape shown in FIG. The thickness L1 of the nozzle plate 31 is 50 μm, the opening on the lower surface is a circle with a diameter D = 20 μm, and a straight portion having a diameter unchanged from the lower surface is provided with a length of L2 = 5 μm. The distance a between the bottom surface of the sub-manifold 5a and the distance b from the bottom surface of the liquid pressurizing chamber 10a to the top surface of the sub-manifold 5a is as follows. It was shown in 1. The printed image was obtained by visual observation and reading the printed barcode.

  As can be seen in Table 1, sample no. For 2-4, 6 and 7, good printing results were obtained even when driven at 30 kHz.

  Further, from the measurement results, the liquid discharge speed at the time of 30 kHz driving and at the time of 20 kHz driving of the liquid discharge hole group including the liquid discharge holes 8 connected to the liquid pressurizing chamber 10a overlapping with the sub manifold 5a when viewed from the upper surface side. As a ratio of (average of liquid discharge speed of liquid discharge holes when driven at a drive frequency of 30 kHz) / (average of liquid discharge speed of liquid discharge holes when driven at a drive frequency of 20 kHz) In the body discharge head, it was in the range of 0.9 to 1.1. Similarly, for the liquid discharge hole group composed of the liquid discharge holes 8 connected to the liquid pressurizing chamber 10a overlapping with the sub manifold 5a when viewed from the upper surface side, the liquid discharge speed ratio between 30 kHz driving and 20 kHz driving is calculated. As a result, the above-described body discharge head was in the range of 0.9 to 1.1.

  Sample No. outside the scope of the present invention. With the liquid discharge heads 1, 5, and 8, good printing results were obtained when driven at 20 kHz, but good printing results were not obtained when driven at 30 kHz.

  FIG. 6 is a measurement result of the liquid discharge speed of one liquid discharge hole among the liquid discharge holes 8 connected to the liquid pressurizing chamber 10a overlapping the sub-manifold 5a in one liquid discharge head. When the drive frequency was up to about 20 kHz, the liquid discharge speed was almost constant. However, when the drive frequency exceeded 20 kHz, the liquid discharge speed increased, and the liquid discharge speed ratio between 30 kHz driving and 20 kHz driving was 1.13. . FIG. This is a result of performing the same measurement in the liquid discharge head of No. 3. The ratio of the liquid discharge speed at the time of 30 kHz driving to 20 kHz driving was 1.06.

  FIG. 2 is a measurement result of a ratio of a liquid discharge speed at the time of 30 kHz driving and 20 kHz driving in one liquid discharge head. Of the rows of liquid discharge holes 8 arranged in 16 rows in the main scanning direction, 2, 3, 6, 7, 10, 11, 14, and 15 rows are connected to the liquid pressurizing chamber 10a overlapping the sub manifold 5a. FIG. 8A shows the liquid discharge speed ratio in the columns of 2 and 3 rows. Since the liquid in the sub-manifold 5a vibrates, the difference in the liquid discharge speed ratio depending on the position in the sub-scanning direction becomes large. FIG. 8B shows sample No. This is a result of performing the same measurement in the liquid discharge head of No. 3. The difference depending on the position in the sub-scanning direction is the sample No. 1 liquid discharge head.

  FIG. FIG. 6 is a measurement result of a liquid discharge speed when one liquid discharge head is driven at 30 kHz, and shows an average of the liquid discharge speed of each column for 16 columns of liquid discharge holes 8 arranged in the main scanning direction. is there. Of the rows arranged in 16 rows in the main scanning direction, the liquid ejection holes 8 in which 2, 3, 6, 7, 10, 11, 14 and 15 rows are connected to the liquid pressurizing chamber 10a overlapping the sub manifold 5a. The liquid discharge speed of these rows tended to be faster than the liquid discharge speed of the liquid discharge holes 8 connected to the liquid pressurizing chamber 10b not overlapping the sub-manifold 5a. FIG. This is a result of performing the same measurement in the liquid discharge head of No. 3. The difference due to the line is the sample No. The number of the liquid discharge heads was smaller than that of the first liquid discharge head.

1 is a schematic configuration diagram of a printer including a liquid ejection head according to an embodiment of the present invention. FIG. 2 is a top view showing a head body that constitutes the liquid ejection head of FIG. 1. FIG. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. 2. FIG. 4 is a longitudinal sectional view taken along line IV-IV in FIG. 3. It is a figure explaining the control part which the printer shown in FIG. 1 has. FIG. 5 is a diagram showing a waveform of a voltage pulse supplied to the individual electrode shown in FIG. 4 during liquid ejection. (A) Sample No. 3 is a measurement result of a liquid discharge speed of one liquid discharge head. (B) Sample No. 3 is a measurement result of the liquid discharge speed of the liquid discharge head of No. 3. (A) Sample No. 3 is a measurement result of a liquid discharge speed of one liquid discharge head. (B) Sample No. 3 is a measurement result of the liquid discharge speed of the liquid discharge head of No. 3. (A) Sample No. 3 is a measurement result of a liquid discharge speed of one liquid discharge head. (B) Sample No. 3 is a measurement result of the liquid discharge speed of the liquid discharge head of No. 3. It is a longitudinal cross-sectional view of a liquid discharge hole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer 2 ... Liquid discharge head 4 ... Flow path member 5 ... Manifold 5a ... Sub manifold 5b ... Opening 6 ... Individual supply flow path 8 ... Liquid discharge hole DESCRIPTION OF SYMBOLS 10 ... Liquid pressurization chamber 10a ... Liquid pressurization chamber which has overlapped with manifold 10b ... Liquid pressurization chamber which has not overlapped with manifold 12 Squeeze 21 Piezoelectric actuator substrate 21a ... Piezoelectric ceramic layer (vibration plate )
21b ... Piezoelectric ceramic layer 22-31 ... Plate 32 ... Individual flow path 34 ... Common electrode 35 ... Individual electrode 36 ... Connection electrode 50 ... Displacement element

Claims (1)

  A flat plate-like body is provided with a manifold to which liquid is supplied from the outside on the lower surface side, and a plurality of liquid pressurizing chambers are provided on the upper surface within the main body. A flow path member provided with a plurality of liquid discharge holes respectively connected to the lower surface of the main body and connected to the plurality of liquid pressurizing chambers, and connected to the individual supply flow path and the throttle from the manifold side in this order; A plurality of displacement elements that respectively pressurize the liquid in the plurality of liquid pressurizing chambers, wherein the plurality of individual supply flow paths have an average of 170 μm or less in the manifold along the longitudinal direction of the main body The liquid pressurizing chambers of the plurality of liquid pressurizing chambers are overlapped with the manifold when viewed from the upper surface side, and the manifold The distance from the lower surface of the liquid pressurizing chamber arranged so as to overlap with the lower surface of the manifold to the lower surface of the manifold is 700 to 1000 μm, and from the lower surface of the liquid pressurizing chamber arranged so as to overlap with the manifold to the upper surface of the manifold A liquid discharge head characterized in that the distance up to 270 to 600 μm.

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