JP5258600B2 - Liquid discharge head and recording apparatus using the same - Google Patents

Description

  The present invention relates to a recording apparatus that prints an image using a liquid discharge head that discharges droplets.

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

  In order to print droplets at a high density in any of the serial type and line type liquid discharge heads, the density of the liquid discharge holes for discharging the droplets formed in the liquid discharge head must be increased. There is a need to.

  Accordingly, the liquid discharge head includes a manifold and a flow path member having a liquid discharge hole that connects the manifold via a plurality of liquid pressurization chambers, and a plurality of displacement elements provided so as to cover the liquid pressurization chambers. A structure in which the actuator units are stacked is known (see, for example, Patent Document 1). In this liquid ejection head, the liquid pressurizing chambers connected to the plurality of liquid ejection holes are arranged in a matrix, and the displacement elements of the actuator unit provided so as to cover the chambers are displaced so that each liquid ejection chamber Ink is ejected and printing is possible at a resolution of 600 dpi in the main scanning direction.

JP 2003-305852 A

  However, the liquid discharge head described in Patent Document 1 is 600 dpi in the main scanning direction and 600 dpi in the sub-scanning direction (hereinafter, A × Bdpi represents Api in the main scanning direction and Bdpi in the sub-scanning direction). Although it is suitable for printing, the liquid ejection holes are two-dimensionally arranged, so even if the resolution in the sub-scanning direction is lowered and only the printing speed, that is, the relative movement speed of the recording medium is increased, There is a problem that a homogeneous image cannot be obtained.

  For example, in a recording apparatus using a liquid discharge head having the liquid discharge hole arrangement shown in FIG. 12A, an image of 600 × 600 dpi can be obtained as shown in FIG. Even if only the relative movement speed is quadrupled, the landing points of the ejected droplets do not have a uniform distribution as shown in FIG. 11C, so that an image of 600 × 150 dpi is not obtained, and 600 × It is not a good image equivalent to 300 dpi.

  On the other hand, it may be possible to cope with this by increasing the frequency of the drive signal for driving the liquid discharge head by four times, but the time interval of the operation of discharging the liquid in the liquid discharge head may be shortened. In such a case, the influence of the crosstalk of the discharge operation becomes large, the image accuracy may be deteriorated, and the control circuit of the liquid discharge head must be changed to one that can be controlled at a high frequency. There is.

  Therefore, an object of the present invention is to provide a liquid discharge head and a recording apparatus that can print at a pseudo high pixel density and can increase the throughput without increasing the driving frequency.

  The liquid discharge head of the present invention is a liquid discharge head including a plurality of liquid discharge holes located on a straight line of n rows (n is an integer of 4 or more) parallel to one direction, and the liquid discharge holes are: The liquid ejection holes are projected at right angles to an imaginary straight line parallel to the one direction and arranged so as not to overlap with a direction perpendicular to the one direction at equal intervals of the distance D (m) in the one direction. A distance in a direction perpendicular to the one direction between the adjacent liquid discharge holes with one liquid discharge hole in between on the virtual straight line is an integral multiple of a predetermined length L (m), A distance in a direction orthogonal to the one direction between the liquid ejection holes adjacent on the virtual straight line is (integer +1/2) times the predetermined length L (m). .

  The liquid discharge head of the present invention is a liquid discharge head including a plurality of liquid discharge holes positioned on a straight line of n rows (n is an integer of 4 or more) parallel to one direction, and the liquid discharge holes Are arranged at equal intervals of the distance D (m) in the one direction and not to overlap with a direction orthogonal to the one direction, and the liquid discharge hole is perpendicular to a virtual straight line parallel to the one direction. When projected, the distance in the direction perpendicular to the one direction between the liquid ejection hole and the liquid ejection hole adjacent on one side thereof on the virtual straight line is an integral multiple of the predetermined length L (m). The distance in the direction orthogonal to the one direction between the liquid discharge holes adjacent to the liquid discharge hole on the other side on the virtual straight line is (integer +1/2) times the predetermined length L (m). It is characterized by being.

  The recording apparatus of the present invention includes any one of the above-described liquid discharge heads and a transport unit that transports the recording medium relative to the liquid discharge head in a direction perpendicular to the one direction at a speed V (m / s). And a controller for controlling the driving of the liquid discharge head.

  Moreover, it is preferable that the frequency of the drive signal sent from the control unit to the liquid ejection head is V / L (Hz).

  Furthermore, it is preferable that L = 2D or L = 4D.

  The liquid discharge head of the present invention is a liquid discharge head including a plurality of liquid discharge holes located on a straight line of n rows (n is an integer of 4 or more) parallel to one direction, and the liquid discharge holes are: The liquid ejection holes are projected at right angles to an imaginary straight line parallel to the one direction and arranged so as not to overlap with a direction perpendicular to the one direction at equal intervals of the distance D (m) in the one direction. A distance in a direction perpendicular to the one direction between the adjacent liquid discharge holes with one liquid discharge hole in between on the virtual straight line is an integral multiple of a predetermined length L (m), The distance in the direction orthogonal to the one direction between the liquid ejection holes adjacent on the virtual straight line is (integer +1/2) times the predetermined length L (m), so that it is perpendicular to the one direction. While moving the recording medium relative to each other When droplets are discharged from the discharge hole, the position of the droplet landing on the recording medium is regularly aligned, good images are acquired.

  The liquid discharge head of the present invention is a liquid discharge head including a plurality of liquid discharge holes positioned on a straight line of n rows (n is an integer of 4 or more) parallel to one direction, and the liquid discharge holes Are arranged at equal intervals of the distance D (m) in the one direction and not to overlap with a direction orthogonal to the one direction, and the liquid discharge hole is perpendicular to a virtual straight line parallel to the one direction. When projected, the distance in the direction perpendicular to the one direction between the liquid ejection hole and the liquid ejection hole adjacent on one side thereof on the virtual straight line is an integral multiple of the predetermined length L (m). The distance in the direction orthogonal to the one direction between the liquid discharge holes adjacent to the liquid discharge hole on the other side on the virtual straight line is (integer +1/2) times the predetermined length L (m). The recording medium in a direction perpendicular to the one direction. While relatively moving, when droplets are discharged from the liquid discharge hole, the position of the droplet landing on the recording medium is regularly aligned, good images are acquired.

  The recording apparatus of the present invention includes any one of the above-described liquid discharge heads and a transport unit that transports the recording medium relative to the liquid discharge head in a direction perpendicular to the one direction at a speed V (m / s). And a controller for controlling the driving of the liquid ejection head, the positions of the droplets that land on the recording medium are regularly aligned, and a good image can be obtained.

  Further, when the frequency of the drive signal sent from the control unit to the liquid ejection head is V / L (Hz), the liquid ejection head having the liquid ejection holes arranged on one straight line parallel to the one direction. A higher resolution image can be obtained than when driving at the same frequency.

  Further, when D = L / 2, an image in which the interval between the landing positions is pseudo D (μm) in the main scanning direction and D (μm) in the sub scanning direction is obtained.

  Furthermore, when D = L / 4, an image is obtained in which the interval between the landing positions is pseudo D (μm) in the main scanning direction and 2 × D (μm) in the sub scanning direction.

1 is a schematic configuration diagram of a printer that is a recording apparatus according to an embodiment of the present invention. FIG. 2 is a plan 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. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. It is a longitudinal cross-sectional view along the VV line of FIG. FIG. 5 is a schematic diagram illustrating an arrangement of liquid discharge holes of a liquid discharge head according to an embodiment of the present invention. (A) is a schematic diagram of the arrangement of the liquid ejection holes shown in FIG. 6, and (b) to (d) are ejected from the liquid ejection head having the arrangement of the liquid ejection holes of (a), and are each 600 × 600 dpi. , 600 × 300 dpi, and a schematic diagram of pixels printed at 600 × 300 dpi. (A) is the schematic diagram of arrangement | positioning of the liquid discharge hole of the liquid discharge head of other this invention, (b), (c) is discharged from the liquid discharge head of arrangement | positioning of the liquid discharge hole of (a), FIG. 5 is a schematic diagram of pixels printed at 600 × 600 dpi and 600 × 600 dpi, respectively. (A) is the schematic diagram of arrangement | positioning of the liquid discharge hole of the liquid discharge head of other this invention, (b), (c) is discharged from the liquid discharge head of arrangement | positioning of the liquid discharge hole of (a), FIG. 5 is a schematic diagram of pixels printed at 600 × 600 dpi and 600 × 600 dpi, respectively. (A)-(d) is a schematic diagram which shows the magnitude | size of the printed pixel. (A) is a schematic diagram of arrangement | positioning of the liquid discharge hole of the conventional liquid discharge head, (b)-(d) is discharged from the liquid discharge head of the arrangement | positioning of the liquid discharge hole of (a), and each is 600 *. FIG. 6 is a schematic diagram of pixels printed at 600 dpi, 600 × 300 dpi, and 600 × 150 dpi. (A) is a schematic diagram of arrangement | positioning of the liquid discharge hole of the conventional liquid discharge head, (b)-(d) is discharged from the liquid discharge head of the arrangement | positioning of the liquid discharge hole of (a), and each is 600 *. FIG. 6 is a schematic diagram of pixels printed at 600 dpi, 600 × 300 dpi, and 600 × 300 dpi.

  FIG. 1 is a schematic configuration diagram of a color ink jet printer which is a recording apparatus 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 ejection holes 8 for ejecting liquid are provided on the lower surface of the head body 13 (see FIG. 3).

  Liquid droplets (ink) of the same color are ejected from the liquid ejection holes 8 provided in one liquid ejection head 2. Since the liquid ejection holes 8 of each liquid ejection head 2 are arranged at equal intervals in one direction (a direction parallel to the printing paper P and perpendicular to the conveyance direction of the printing paper P and the longitudinal direction of the liquid ejection head 2), Printing can be performed without gaps in one direction. 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, droplets are ejected from the head main body 13 constituting the liquid ejection 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. FIG. 4 is an enlarged perspective view of the same position as in FIG. 3, in which some of the flow paths are omitted so that the position of the liquid discharge holes 8 can be easily understood. 3 and 4, in order to make the drawings easy to understand, the liquid pressurizing chamber 10 (liquid pressurizing chamber group 9), the squeezing 12, and the liquid discharge holes which are to be drawn by broken lines below the piezoelectric actuator unit 21. 8 is drawn with a solid line. FIG. 5 is a longitudinal sectional view taken along line VV in FIG.

The head body 13 includes a flat plate-like flow path member 4 and a piezoelectric actuator unit 21 that is an actuator unit on the flow path member 4. The piezoelectric actuator unit 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. Further, two piezoelectric actuator units 21 are arranged on the flow path member 4 as a whole in a zigzag manner, two along each of two virtual straight lines parallel to the longitudinal direction of the flow path member 4. Yes. The oblique sides of the piezoelectric actuator units 21 adjacent to each other on the flow path member 4 partially overlap in the short direction of the flow path member 4. In the region printed by driving the overlapping piezoelectric actuator unit 21, the droplets ejected by the two piezoelectric actuator units 21 are mixed and landed.
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 units 21 are disposed. The manifold 5 is supplied with liquid from a liquid tank (not shown) through the opening 5b.

  The manifold 5 formed in the flow path member 4 is branched into a plurality of branches (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 unit 21 and is disposed so as to intersect with the longitudinal direction of the flow path member 4. In a region sandwiched between two piezoelectric actuator units 21, one manifold 5 is shared by adjacent piezoelectric actuator units 21, and the sub-manifold 5 a branches off 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 regions facing the piezoelectric actuator units 21 inside the flow path member 4.

  The flow path member 4 has four liquid pressurizing chamber groups 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 unit 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 unit 21. Further, the opening of each liquid pressurizing chamber 10 is closed by adhering the piezoelectric actuator unit 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 E1-E4 sub-manifolds 5a arranged in parallel with each other in the short direction of the flow path member 4, and each sub-manifold The liquid pressurizing chambers 10 connected to 5a constitute a row of liquid pressurizing chambers 10 arranged in the longitudinal direction of the flow path member 4 at equal intervals, and the four rows are arranged in parallel to each other in the short direction. Yes. Two rows of liquid pressurizing chambers 10 connected to the sub-manifold 5a are arranged on both sides of the sub-manifold 5a.

  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 that is an actuator. ing. 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 intervals corresponding to 150 dpi on average. This is because the individual flow paths 32 connected to the sub-manifolds 5a are not always connected at equal intervals when the 600 dpi liquid discharge holes 8 are divided and connected to the four sub-manifolds 5a. This means that the individual flow paths 32 are formed at intervals of an average of 170 μm (25.4 mm / 150 = 169 μm intervals if 150 dpi) in the extending direction of 5a, that is, the main scanning direction.

  Individual electrodes 35 to be described later are formed at positions facing the liquid pressurizing chambers 10 on the upper surface of the piezoelectric actuator unit 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 unit 21. Is arranged.

  A large number of liquid discharge holes 8 are formed in the liquid discharge surface on the lower surface of the flow path member 4. These liquid discharge holes 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 holes 8 are arranged in a region facing the piezoelectric actuator unit 21 on the lower surface side of the flow path member 4. These liquid discharge hole groups 7 occupy an area having almost the same size and shape as the piezoelectric actuator unit 21, and the liquid discharge holes 8 are made to drop liquid by displacing the displacement element 50 of the corresponding piezoelectric actuator unit 21. Can be discharged. The arrangement of the liquid discharge holes 8 will be described in detail later. The liquid discharge holes 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.

  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. 5, the head main body 13 has a liquid pressurizing chamber 10 on the upper surface of the flow path member 4, the sub-manifold 5a on the inner lower surface side, and the liquid discharge holes 8 on the lower surface. Each portion constituting the path 32 is disposed close to each other at different positions, and the sub manifold 5 a and the liquid discharge hole 8 are connected via the liquid pressurizing chamber 10.

  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 hole 8, and this communication hole is referred to as a descender (partial flow channel) in the following description. . The descender is formed on each plate from the base plate 23 (specifically, the outlet of the liquid pressurizing chamber 10) to the nozzle plate 31 (specifically, the liquid discharge hole 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 from the liquid inflow port (the outlet of the submanifold 5a) from the submanifold 5a to the liquid discharge hole 8. The liquid supplied to the sub manifold 5a is discharged from the liquid discharge hole 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 hole 8 opened on the lower surface.

  As shown in FIG. 5, the piezoelectric actuator unit 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 unit 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 unit 21 includes 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 unit 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 drive signal is supplied to the individual electrode 35 from the control unit 100 through the FPC. The drive signal is supplied in a constant cycle in synchronization with the conveyance speed of the print medium P.

  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 unit 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. 5, the common electrode 34 and the individual electrode 35 are disposed 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 21b is referred to as an active portion, and the piezoelectric ceramic in that portion is polarized. In the piezoelectric actuator unit 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 unit 21 has a so-called unimorph type configuration.

  As will be described later, when a predetermined drive signal 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, droplets are discharged from the corresponding liquid discharge ports 8 through the individual flow paths 32. That is, the portion of the piezoelectric actuator unit 21 that faces 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. 5 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 unit 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).

  A large number of individual electrodes 35 are individually electrically connected to the actuator control means via contacts and wirings on the FPC so that potentials can be individually controlled.

In the piezoelectric actuator unit 21 in the present embodiment, when an electric field is applied in the polarization direction to the piezoelectric ceramic layer 21b by setting the individual electrode 35 to a potential different from that of the common electrode 34, the portion to which this electric field is applied is piezoelectric. It works as an active part that is distorted by the effect. At this time, the piezoelectric ceramic layer 21b expands or contracts in the thickness direction, that is, the stacking direction, and tends to contract or extend in the direction perpendicular to the stacking direction, that is, the plane direction by the piezoelectric lateral effect. On the other hand, since the remaining piezoelectric ceramic layer 21a is an inactive layer that does not have a region sandwiched between the individual electrode 35 and the common electrode 34, it does not spontaneously deform. In other words, the piezoelectric actuator unit 21 uses the upper piezoelectric ceramic layer 21b (that is, the side away from the liquid pressurizing chamber 10) as a layer including the active portion and the lower side (that is, close to the liquid pressurizing chamber 10). In this configuration, the individual electrodes 35 are connected to the common electrode 34 by the actuator controller so that the electric field and the polarization are in the same direction. When the potential is positive or negative, the portion (active portion) sandwiched between the electrodes of the piezoelectric ceramic layer 21b contracts in the plane direction. On the other hand, the piezoelectric ceramic layer 21a, which is an inactive layer, is not affected by an electric field, so that it does not spontaneously shrink and tries to restrict deformation of the active portion. As a result, there is a difference in strain in the polarization direction between the piezoelectric ceramic layer 21b and the piezoelectric ceramic layer 21a, and the piezoelectric ceramic layer 21b is deformed so as to protrude toward the liquid pressurizing chamber 10 (unimorph deformation). .

  In the actual driving procedure in this embodiment, the individual electrode 35 is set to a potential higher than the common electrode 34 (hereinafter referred to as a high potential) in advance, and the individual electrode 35 is temporarily set to the same potential as the common electrode 34 every time there is a discharge request. (Hereinafter referred to as a low potential), and then set to a high potential again at a predetermined timing. As a result, the piezoelectric ceramic layers 21a and 21b return to the original shape at the timing when the individual electrode 35 becomes low potential, and the volume of the liquid pressurizing chamber 10 is compared with the initial state (the state where the potentials of both electrodes are different). To increase. At this time, a negative pressure is applied to the liquid pressurizing chamber 10 and the liquid is sucked into the liquid pressurizing chamber 10 from the manifold 5 side. Thereafter, at the timing when the individual electrode 35 is set to a high potential again, the piezoelectric ceramic layers 21a and 21b are deformed so as to protrude toward the liquid pressurizing chamber 10, and the volume of the liquid pressurizing chamber 10 is reduced so that the inside of the liquid pressurizing chamber 10 Becomes a positive pressure, the pressure on the liquid rises, and droplets are ejected. That is, a drive signal including a pulse based on a high potential is supplied to the individual electrode 35 in order to eject a droplet. The ideal pulse width is AL (Acoustic Length), which is the length of time during which the pressure wave propagates from the manifold 5 to the liquid discharge hole 8 in the liquid pressurizing chamber 10. According to this, when the inside of the liquid pressurizing chamber 10 is reversed from the negative pressure state to the positive pressure state, both pressures are combined, and the liquid droplet can be ejected with a stronger pressure.

  In gradation printing, gradation expression is performed by the number of droplets ejected continuously from the liquid ejection holes 8, that is, the droplet amount (volume) adjusted by the number of droplet ejections. For this reason, the number of droplet discharges corresponding to the specified gradation expression is continuously performed from the liquid discharge hole 8 corresponding to the specified dot region. In general, when liquid ejection is performed continuously, it is preferable that the interval between pulses supplied to eject liquid droplets is AL. As a result, the period of the residual pressure wave of the pressure generated when discharging the previously discharged liquid droplet coincides with the pressure wave of the pressure generated when discharging the liquid droplet discharged later, and these are superimposed. Thus, the pressure for discharging the droplet can be amplified.

  In such a printer 1, by adjusting the period to the conveyance speed and drive signal of the printing paper P, an image having a resolution of 600 dpi in the longitudinal direction and 600 dpi in the conveyance direction can be recorded. For example, if the drive signal is 20 kHz and the transport speed is 0.83 m / sec, the discharged droplets can land on the printing paper P every about 42 μm in the transport direction, and the resolution in the transport direction is 600 dpi. .

  Here, the details of the arrangement of the liquid discharge holes used in the following description are shown in Table 1. In Table 1, the liquid body discharge hole arrangement, which is arranged for each distance D in one direction and is repeated every 16 pieces (distance 16D), is the liquid discharge hole No. that is the liquid discharge hole at the extreme end (the left end in each figure). . The distance in the direction perpendicular to one direction with respect to the liquid discharge hole No. They are listed in order from 1.

  In order to increase the printing throughput, it is only necessary to increase the conveyance speed and the frequency of the drive vibration. However, if the frequency of the drive vibration is made higher than a certain level, the time from the end of one discharge to the next discharge is shortened, so the residual vibration of the liquid increases and the discharge characteristics fluctuate and a good image can be recorded. There is a fear. In addition, when the frequency of the drive vibration is increased, problems such as an increase in the influence of crosstalk and a problem that the control circuit 100 must be capable of handling high frequencies occur.

  Therefore, it is conceivable to increase the printing throughput without increasing the drive frequency by reducing the resolution in the transport direction. For example, in a printer using a liquid discharge head in which liquid discharge holes as shown in FIG. 11A are arranged in a straight line at 600 dpi, if printing is performed at an appropriate driving frequency and conveyance speed, FIG. An image of 600 × 600 dpi as shown in b) can be recorded. If the conveyance speed is doubled without changing the drive frequency, an image of 600 × 300 dpi as shown in FIG. 11C can be recorded, and if the conveyance speed is quadrupled, the image is transferred to FIG. 11D. An image of 600 × 150 dpi as shown can be recorded.

  However, in a printer in which the liquid discharge holes are two-dimensionally distributed as described above, the landing position is limited by the two-dimensional distribution of the liquid discharge holes, so that a good image can be obtained even if the transport speed is simply increased. It is not necessarily obtained. Also, a 600 × 300 dpi image or a 600 × 150 dpi image printed by a printer using a liquid ejection head in which liquid ejection holes as shown in FIG. Since the pixels have landed in a regular arrangement, a good image can be obtained at that point, but the resolution is different between the main scanning direction and the sub-scanning direction, so that the image is not good at that point. In particular, at 600 × 150 dpi, the pixel density varies greatly depending on the direction, so that it cannot be said that the image quality when viewed with human eyes is good.

  FIG. 12A shows an arrangement E of the liquid ejection holes in the liquid ejection head outside the scope of the present invention, which is an example of the liquid ejection holes capable of printing of 600 × 600 dpi as shown in FIG. In the arrangement E, when the liquid discharge holes are projected at right angles to a virtual straight line parallel to one direction, the distances in the direction perpendicular to one direction of the adjacent liquid discharge holes are all distances D ( m) is an integral multiple of m). In such an arrangement, when the printing paper is moved at a speed V (m) and a drive signal having a frequency V / D (Hz) is given to the print head, D (m) in one direction and a direction orthogonal to one direction In addition, pixels with an interval of D (m) can be printed. The image printed in this way is a 600 × 600 dpi image shown in FIG.

  When the liquid ejection holes are projected at right angles to an imaginary straight line parallel to one direction, the arrangement E is a distance in which all the distances in the direction perpendicular to one direction of the adjacent liquid ejection holes are arranged in one direction of the liquid ejection holes. It is an integer multiple of 2D (m). In such an arrangement, when the printing paper is moved at a speed of 2 V (m / s) and a drive signal having a frequency V / D (Hz) is given to the print head, D (m) in one direction and orthogonal to one direction Pixels with an interval of 2D (m) can be printed in the direction to be printed. In this way, a 600 × 300 dpi image shown in FIG. 12C is printed with the conveyance speed doubled. However, when the conveyance speed is increased by a factor of 4, the period of pixel distribution becomes large as shown in FIG. 12D, and the image quality when viewed with the human eye cannot be said to be good.

  FIG. 6 and FIG. 7A show an arrangement A that is an example of the arrangement of the liquid ejection holes of the liquid ejection head of the present application. In the arrangement A, the liquid discharge holes are arranged on 16 straight lines parallel to one direction (only the virtual straight lines L1 and L2 are shown), and the distance between the liquid discharge holes in one direction is equal to the distance D (m). And the liquid discharge holes are arranged so as not to overlap in a direction orthogonal to one direction, and when the liquid discharge holes are projected at right angles to a virtual straight line L parallel to the one direction, The distance in the direction orthogonal to one direction between adjacent liquid discharge holes with one liquid discharge hole in between is an integral multiple of the length 4D (m), and adjacent liquid discharges on the virtual straight line L The distance in the direction perpendicular to one direction between the holes is (integer +1/2) times the length 4D (m).

  This is because, in the arrangement A, when the liquid ejection holes are projected at right angles to a virtual straight line L parallel to one direction, the distances in the direction perpendicular to one direction of the adjacent liquid ejection holes are all arranged in one direction of the liquid ejection holes. It also means that it is an integral multiple of the distance D (m).

  Specifically, this is the following arrangement. The third liquid discharge hole No. 3 from the left in FIG. 3 centered on one liquid discharge hole, one liquid discharge hole is placed on the left side and adjacent liquid discharge holes No. 1 is 72D (72D-0D from Table 1), and is an integral multiple of 4D. One liquid discharge hole is placed on the right side and adjacent liquid discharge holes No. . 5 is 12D (72D-60D from Table 1) in the direction orthogonal to one direction, and is an integral multiple of 4D. 2 is 70D (142D-70D from Table 1) in the direction orthogonal to one direction, and is (integer +1/2) times 4D. The distance in a direction orthogonal to one direction with respect to 4 is 142D (214D-72D from Table 1), so it is (integer +1/2) times 4D.

  In such an arrangement, when the printing paper is moved at a speed V (m) and a drive signal having a frequency V / D (Hz) is given to the print head, D (m) in one direction and a direction orthogonal to one direction In addition, pixels with an interval of D (m) can be printed. A 600 × 600 dpi image shown in FIG. 7B is printed in this way.

  Further, in the arrangement A, when the liquid discharge holes are projected at right angles to a virtual straight line parallel to one direction, the distances in the direction perpendicular to one direction of the adjacent liquid discharge holes are all integral multiples of 2D (m). Yes. In such an arrangement, when the printing paper is moved at a speed of 2 V (m / s) and a drive signal having a frequency V / D (Hz) is given to the print head, D (m) in one direction and orthogonal to one direction Pixels with an interval of 2D (m) can be printed in the direction to be printed. In this way, a 600 × 300 dpi image shown in FIG. 7C is printed with the conveyance speed doubled.

  Furthermore, in the arrangement A, when the liquid ejection holes are projected at right angles to a virtual straight line parallel to one direction, one liquid ejection hole is placed on the virtual straight line in one direction between adjacent liquid ejection holes. The distance in the orthogonal direction is an integral multiple of 4D (m), and the distance in the direction orthogonal to one direction between the liquid ejection holes adjacent on the virtual straight line L is 4D (m) (integer + 1 / 2) Doubled. In such an arrangement, if the printing paper is moved at a speed of 4 V (m / s) and a drive signal having a frequency of V / D (Hz) is given to the print head, one direction as shown in FIG. D (m) can be printed in a pseudo manner, and pixels with a spacing of 2D (m) can be printed in a direction perpendicular to one direction. This is because the displacement of the landing position in the direction perpendicular to one direction due to the two-dimensional arrangement of the liquid discharge holes is the same as the amount of landing at the center of the four adjacent pixels at the landing position. Because it is. By doing so, four times the throughput can be obtained without increasing the driving frequency, and the obtained image is a pseudo 600 × 300 dpi image with little difference between one direction and the direction orthogonal thereto, An image that looks good to the human eye is obtained.

  In this case, the image data may be data at a corresponding position of 600 × 600 dpi data of the original image. If the original image is 300 × 300 dpi, a position that is not in the original data may be calculated from adjacent image data by arithmetic average or the like. Further, the arrangement of the pixels after landing in this case is as shown in FIGS. The lattice is 600 × 600 dpi. If the pixel size is the same as in the case of 600 × 600 dpi, the number of portions where pixels are not formed increases. Therefore, the maximum diameter of pixels to be printed is twice the maximum diameter of pixels at the time of 600 × 600 dpi printing, that is, 300 × 300 dpi. It is preferable that the size of the pixels inscribed in one grid is used.

  In general, the above relationship is such that a distance in a direction perpendicular to one direction between adjacent liquid discharge holes is set to a predetermined length L (m) between the adjacent liquid discharge holes on the virtual straight line L. Liquid discharge is an integral multiple, and the distance in the direction orthogonal to one direction between adjacent liquid discharge holes on the virtual straight line L is (integer + 1/2) times the predetermined length L (m). In the arrangement of holes, when driven by a drive signal having a conveyance speed V (m / s and a frequency of V / L (Hz), the interval between pixels in one direction is D (m) and is orthogonal to one direction. An image having a pixel spacing of L / 2 (m) in the direction is obtained.

  The arrangement B shown in Table 1 also has the same characteristics as the arrangement A and is an arrangement that can obtain the same effect.

  FIG. 8A shows an arrangement C that is an example of the arrangement of the liquid discharge holes of the liquid discharge head of the present application. In the arrangement C, the liquid discharge holes are arranged on 16 straight lines parallel to one direction (only the imaginary straight line L1 is shown), and the intervals in one direction of the liquid discharge holes are equal to the distance D (m). And the liquid discharge holes are arranged so as not to overlap in a direction orthogonal to one direction, and when the liquid discharge holes are projected at right angles to a virtual straight line parallel to the one direction, one is placed on the virtual straight line. The distance in the direction orthogonal to one direction between the adjacent liquid discharge holes with the liquid discharge hole being an integral multiple of 2D (m), and between the adjacent liquid discharge holes on the virtual straight line L On the other hand, the distance in the direction orthogonal to the direction is (integer +1/2) times 2D (m).

  This is because in the arrangement C, when the liquid ejection holes are projected at right angles to a virtual straight line L parallel to one direction, the distances in the direction perpendicular to one direction of the adjacent liquid ejection holes are all arranged in one direction of the liquid ejection holes. It also means that it is an integral multiple of the distance D (m). In such an arrangement, when the printing paper is moved at a speed V (m) and a drive signal having a frequency V / D (Hz) is given to the print head, D (m) in one direction and a direction orthogonal to one direction In addition, pixels with an interval of D (m) can be printed. The image printed in this way is a 600 × 600 dpi image shown in FIG.

  In the arrangement C, when the liquid ejection holes are projected at right angles to a virtual straight line parallel to one direction, one liquid ejection hole is placed between the adjacent liquid ejection holes on the virtual straight line. The distance in the direction in which the liquid is discharged is an integer multiple of 2D (m), and the distance in the direction perpendicular to one direction between the liquid ejection holes adjacent on the virtual straight line is 2D (m) (integer +1/2) It has doubled. In such an arrangement, when the printing paper is moved at a speed of 2 V (m / s) and a drive signal having a frequency of V / D (Hz) is given to the print head, one direction as shown in FIG. D (m) can be printed in a pseudo manner, and pixels with a spacing of D (m) can be printed in a direction orthogonal to one direction. This is because the displacement of the landing position in the direction perpendicular to one direction due to the two-dimensional arrangement of the liquid discharge holes is the same as the amount of landing at the center of the four adjacent pixels at the landing position. Because it is. This makes it possible to obtain twice the throughput without increasing the driving frequency, and the obtained image is a pseudo 600 × 600 dpi image with the same pixel arrangement in one direction and the direction orthogonal thereto. An image that looks good to the human eye is obtained.

  In this case, the image data may be data at a corresponding position of 600 × 600 dpi data of the original image. If the original image is 300 × 300 dpi, a position that is not in the original data may be calculated from adjacent image data by arithmetic average or the like. Further, the arrangement of the pixels after landing in this case is as shown in FIGS. The lattice is 600 × 600 dpi. If the size of the pixel is the same as that of 600 × 600 dpi, the number of portions where pixels are not formed increases. Therefore, the maximum diameter of the pixel to be printed is a square root of 2 times the maximum diameter of the pixel at 600 × 600 dpi, that is, 450 × The pixel size is preferably inscribed in one grid of 450 dpi.

  FIG. 9A shows an arrangement D that is an example of the arrangement of the liquid discharge holes of the liquid discharge head of the present application. In the arrangement D, the liquid discharge holes are arranged on 16 straight lines parallel to one direction (only the virtual straight line L1 is shown), and the intervals in one direction of the liquid discharge holes are equal to the distance D (m). And the liquid discharge holes are arranged so as not to overlap in a direction orthogonal to one direction, and when the liquid discharge holes are projected perpendicularly to a virtual straight line parallel to the one direction, one liquid discharge is made on the virtual straight line. The distance in the direction orthogonal to one direction between the hole and the liquid discharge hole adjacent on one side thereof is an integral multiple of 2D (m), and is adjacent to the one liquid discharge hole on the other side on the virtual straight line. The distance in the direction orthogonal to the one direction between the matching liquid discharge holes is (integer +1/2) times 2D (m).

  Specifically, this is the following arrangement. The second liquid discharge hole No. 2 from the left in FIG. 2 centering on the liquid discharge hole No. 2, the liquid discharge hole No. Since the distance in the direction orthogonal to one direction is 142D, it is an integral multiple of 2D. 3 is 71D (142D-71D from Table 1) in the direction orthogonal to one direction, and is therefore (integer +1/2) times 2D. In other words, the distance in the direction perpendicular to one direction between the adjacent liquid ejection holes in the imaginary straight line alternately takes a value that is an integer multiple of 2D and a value that is an integer +1/2 times 2D. It is.

  In the arrangement D, when the liquid ejection holes are projected at right angles to the virtual straight line L parallel to one direction, the distances in the direction perpendicular to one direction of the adjacent liquid ejection holes are all arranged in one direction of the liquid ejection holes. It also means that it is an integral multiple of the distance D (m). In such an arrangement, when the printing paper is moved at a speed V (m) and a drive signal having a frequency V / D (Hz) is given to the print head, D (m) in one direction and a direction orthogonal to one direction In addition, pixels with an interval of D (m) can be printed. The image printed in this way is a 600 × 600 dpi image shown in FIG.

  In the arrangement D, when the liquid discharge holes are projected at right angles to a virtual straight line parallel to one direction, it is orthogonal to one direction between one liquid discharge hole and one adjacent liquid discharge hole on the virtual straight line. And the distance in the direction orthogonal to one direction between the one liquid discharge hole and the liquid discharge hole adjacent on the other side on the virtual straight line is 2D (m). ) (Integer + 1/2) times. In such an arrangement, when the printing paper is moved at a speed of 2 V (m / s) and a drive signal having a frequency V / D (Hz) is given to the print head, one direction as shown in FIG. D (m) can be printed in a pseudo manner, and pixels with a spacing of D (m) can be printed in a direction orthogonal to one direction. This is because the displacement of the landing position in the direction orthogonal to one direction due to the two-dimensional arrangement of the liquid discharge holes is the same as the amount of landing in a regular arrangement with respect to adjacent pixels at the landing position. It is because of. In this way, twice the throughput can be obtained without increasing the drive frequency, and the obtained image has a regular pixel arrangement in one direction and a direction orthogonal thereto, and a pseudo 600 × 600 dpi. It becomes an image, and an image that looks good to human eyes is obtained.

  In this case, the image data may be data at a corresponding position of 600 × 600 dpi data of the original image. If the original image is 300 × 300 dpi, a position that is not in the original data may be calculated from adjacent image data by arithmetic average or the like.

  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 modifications can be made as long as they are described in the claims. For example, the number of liquid ejection holes may be any number as long as the number is 4 or more.

  Note that the number of liquid ejection hole rows is set to 4 or more in order to prevent crosstalk from being simultaneously ejected from adjacent liquid ejection holes when projected vertically onto a virtual straight line. This is because the number of columns is four or more.

  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 unit 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 unit 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, but in order not to affect the piezoelectric actuator unit 21 and the flow path member 4, an epoxy resin, phenol resin, polyphenylene 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 ether resins. By heating to the thermosetting temperature using such an adhesive layer, the piezoelectric actuator unit 21 and the flow path member 4 can be heated and joined to obtain the liquid ejection head 2.

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 9 ... Liquid pressurization chamber group 10 ... Liquid pressurization chamber 11a, b, c, d ... Liquid pressurization chamber row | line | column 12 ... Squeeze 15a, b, c, d ... Liquid discharge hole Row 21 ... Piezoelectric actuator unit 21a ... Piezoelectric ceramic layer (vibrating 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 (6)

  A liquid discharge head including a plurality of liquid discharge holes positioned on a straight line of n rows (n is an integer of 4 or more) parallel to one direction, wherein the liquid discharge hole is a distance D (m ) At equal intervals and so as not to overlap in the direction orthogonal to the one direction, and when the liquid discharge holes are projected perpendicularly to a virtual straight line parallel to the one direction, The distance in the direction perpendicular to the one direction between the adjacent liquid discharge holes is one integer multiple of a predetermined length L (m), and the adjacent liquid discharge holes are adjacent to each other on the virtual straight line. A liquid discharge head, wherein a distance between the liquid discharge holes in a direction orthogonal to the one direction is (integer +1/2) times the predetermined length L (m).   A liquid discharge head including a plurality of liquid discharge holes positioned on a straight line of n rows (n is an integer of 4 or more) parallel to one direction, wherein the liquid discharge hole is a distance D (m ) At equal intervals and so as not to overlap in a direction orthogonal to the one direction, and when the liquid ejection holes are projected perpendicularly to a virtual straight line parallel to the one direction, A distance in a direction orthogonal to the one direction between the liquid discharge hole and the liquid discharge hole adjacent on one side thereof is an integral multiple of a predetermined length L (m), and the liquid discharge hole on the virtual straight line And a distance in a direction orthogonal to the one direction between the liquid discharge holes adjacent to each other on the other side is (integer +1/2) times the predetermined length L (m). .   The liquid discharge head according to claim 1, a transport unit that transports a recording medium relative to the liquid discharge head in a direction perpendicular to the one direction at a speed V (m / s), and the liquid discharge And a control unit that controls driving of the head. The recording apparatus according to claim 3, wherein a frequency of a drive signal sent from the control unit to the liquid ejection head is V / L (Hz).   The recording apparatus according to claim 4, wherein D = L / 2.   5. A recording apparatus according to claim 4, wherein D = L / 4.

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