WO2015198944A1

WO2015198944A1 - Liquid-discharging head and recording apparatus using same

Info

Publication number: WO2015198944A1
Application number: PCT/JP2015/067480
Authority: WO
Inventors: 小林　直樹
Original assignee: 京セラ株式会社
Priority date: 2014-06-27
Filing date: 2015-06-17
Publication date: 2015-12-30
Also published as: JP6272480B2; JPWO2015198944A1

Abstract

[Problem] To provide a liquid-discharging head capable of increasing recording accuracy and a recording apparatus using same. [Solution] In this liquid-discharging head: multiple discharging holes (8) for discharging a liquid are disposed in n rows (discharging hole rows (9B)) that are roughly parallel to each other; a first discharging hole (8-1) and a third discharging hole (8-3) are located on the first row; a second discharging hole (8-2) and a fourth discharging hole (8-4) are located on the n^th row; the discharging holes (8) belonging to the 2^nd - (n-1)^th rows are disposed on a straight discharging hole line (9A) from the first discharging hole (8-1) toward the fourth discharging hole (8-4); and, in relation to a second direction, the discharging hole line (9A) is obtained from a first array (9A-1) between the first discharging hole (8-1) and the second discharging hole (8-2), a second array (9A-2) between the second discharging hole (8-2) and the third discharging hole (8-3), and a third array (9A-3) between the third discharging hole (8-3) and the fourth discharging hole (8-4).

Description

Liquid discharge head and recording apparatus using the same

The present invention relates to a liquid discharge head and a recording apparatus using the same.

Conventionally, as a print head, for example, a liquid discharge head that performs various types of printing by discharging a liquid onto a recording medium is known. The liquid discharge head includes, for example, a discharge hole for discharging a liquid, a pressurization chamber in which the liquid is pressurized so that the liquid is discharged from the discharge hole, and a common flow path for supplying the liquid to the pressurization chamber. Is known. Further, the liquid in the common flow path and the pressurizing chamber is less likely to be clogged due to the liquid remaining in the common flow path and the pressurizing chamber. A liquid discharge head that circulates the liquid is also known (see, for example, Patent Document 1). The liquid discharge head of Patent Document 1 is long in one direction, the common flow path extends along the short direction of the liquid discharge head, and the discharge holes are arranged along the common flow path.

JP 2008-200902 A

In the arrangement of the ejection holes described in Patent Document 1, when printing on a recording medium, the droplets ejected from the ejection holes located at one end in the short direction and the ejection holes located at the other end The droplets ejected from the ink are printed next to each other on the recording medium. When the liquid ejection head is installed in a state where the installation angle of the liquid ejection head is deviated with respect to the moving direction of the recording medium, the distance between the adjacently printed pixels is deviated from the original distance. End up. The deviation in the distance increases in proportion to the deviation in the installation angle and the distance in the short direction between the ejection holes from which the droplets serving as the pixels printed next to each other are ejected. Therefore, in the arrangement of the discharge holes described in Patent Document 1, the variation in the distance between the pixels increases, and the recording accuracy decreases.

Accordingly, an object of the present invention is to provide a liquid discharge head capable of increasing the recording accuracy and a recording apparatus using the same.

The liquid ejection head of the present invention is a liquid ejection head having a plurality of ejection holes for ejecting liquid. When the liquid ejection head is viewed in plan, the plurality of ejection holes are substantially parallel to each other, n (n is An integer of 5 or more), and the n rows are arranged in a first direction, which is a direction intersecting the n rows, the first row, the second row, ... arranged in the order of the n-th row, one discharge hole belonging to the first row is defined as the first discharge hole, and among the discharge holes belonging to the n-th row, The discharge hole having the second shortest distance from the first discharge hole is the second discharge hole, the fourth discharge hole is the fourth discharge hole, and the direction from the second discharge hole toward the fourth discharge hole is The discharge that is in the second direction and belongs to the first row and is located in the second direction with respect to the first discharge hole Among these, when the discharge hole having the shortest distance from the first discharge hole is the third discharge hole, the first to fourth discharge holes are the first discharge hole and the first discharge hole in the second direction. The two discharge holes, the third discharge hole, and the fourth discharge hole are arranged in this order, and the discharge holes belonging to the 2nd to (n-1) th rows are from the first discharge hole to the fourth discharge hole. The discharge hole array includes one discharge hole belonging to each of the 2 to n-1 lines, and the discharge hole array includes: With respect to the second direction, a first arrangement of the discharge holes arranged between the first discharge holes and the second discharge holes, and a arrangement between the second discharge holes and the third discharge holes. The second arrangement of the discharge holes, and the third arrangement from the third discharge hole to the fourth discharge hole Characterized in that it consists of a third array of said discharge hole being.

Further, the liquid discharge head of the present invention is a liquid discharge head having a plurality of discharge holes for discharging a liquid. When the liquid discharge head is viewed in plan, the plurality of discharge holes are substantially parallel to each other n ( n is an integer greater than or equal to 5). The n rows are arranged in a first direction, which is a direction intersecting the n rows. Are arranged in the order of the rows,..., The n-th row, and one of the discharge holes belonging to the first row is defined as a first discharge hole, and among the discharge holes belonging to the n-th row The third shortest discharge hole from the first discharge hole is the second discharge hole, the fifth shortest discharge hole is the fourth discharge hole, and the second discharge hole is directed to the fourth discharge hole. The direction is the second direction, belongs to the first row, and is located in the second direction with respect to the first discharge hole Among the outlet holes, when the discharge hole having the shortest distance from the first discharge hole is the third discharge hole, the first to fourth discharge holes are the first discharge hole, The third discharge holes, the second discharge holes, and the fourth discharge holes are arranged in this order, and the discharge holes belonging to the 2nd to (n-1) th rows are arranged from the first discharge holes to the fourth discharge holes. The discharge hole array is arranged in a straight line toward the discharge holes, and the discharge hole array includes one discharge hole belonging to each of the 2nd to (n-1) th lines, and the discharge hole array Is a first array of the ejection holes arranged between the first ejection holes and the third ejection holes in the second direction, and between the third ejection holes and the second ejection holes. A second array of the ejection holes arranged in the space between the second ejection hole and the fourth ejection hole. Characterized in that it consists of a third array of said discharge hole being location.

Furthermore, the recording apparatus of the present invention includes the liquid discharge head, a transport unit that transports a recording medium to the liquid discharge head, and a control unit that controls the liquid discharge head.

The nozzle plate, the liquid discharge head, and the recording apparatus using the same according to the present invention can increase the recording accuracy.

(A) is a side view of a recording apparatus including a liquid ejection head according to an embodiment of the present invention, and (b) is a plan view. (A) is a top view of the head main body which is the principal part of the liquid discharge head of FIG. 1, (b) is a top view which remove | excluded the 2nd flow-path member from (a). FIG. 3 is an enlarged plan view of a part of FIG. FIG. 3 is an enlarged plan view of a part of FIG. (A) is a partial longitudinal cross-sectional view along the line VV in FIG. 4, and (b) is a partial vertical cross-sectional view of the head main body in FIG. 2 (a). It is discharge hole arrangement | positioning in one Embodiment of this invention. (A), (b) is discharge hole arrangement | positioning in other embodiment of invention. (A), (b) is discharge hole arrangement | positioning in other embodiment of invention. It is a figure for demonstrating discharge hole arrangement | positioning.

FIG. 1A is a schematic side view of a color inkjet printer 1 (hereinafter sometimes simply referred to as a printer) which is a recording apparatus including a liquid discharge head 2 according to an embodiment of the present invention. (B) is a schematic plan view. The printer 1 moves the print paper P relative to the liquid ejection head 2 by transporting the print paper P as a recording medium from the guide roller 82 </ b> A to the transport roller 82 </ b> B. The control unit 88 controls the liquid ejection head 2 based on image and character data, ejects liquid toward the recording medium P, causes droplets to land on the printing paper P, and prints on the printing paper P. Record such as.

In this embodiment, the liquid discharge head 2 is fixed to the printer 1, and the printer 1 is a so-called line printer. As another embodiment of the recording apparatus of the present invention, the operation of moving the liquid ejection head 2 by reciprocating in the direction intersecting the transport direction of the printing paper P, for example, the direction substantially orthogonal, and the printing paper P There is a so-called serial printer that alternately conveys.

The printer 1 has a flat head mounting frame 70 (hereinafter sometimes simply referred to as a frame) fixed so as to be substantially parallel to the printing paper P. The frame 70 is provided with 20 holes (not shown), and the 20 liquid discharge heads 2 are mounted in the respective hole portions, and the portion of the liquid discharge head 2 that discharges the liquid is the printing paper P. It has come to face. The distance between the liquid ejection head 2 and the printing paper P is, for example, about 0.5 to 20 mm. The five liquid ejection heads 2 constitute one head group 72, and the printer 1 has four head groups 72.

The liquid discharge head 2 has a long and narrow shape in the direction from the front to the back in FIG. 1A and in the vertical direction in FIG. This long direction is sometimes called the longitudinal direction. Within one head group 72, the three liquid ejection heads 2 are arranged along a direction that intersects the conveyance direction of the printing paper P, for example, a substantially orthogonal direction, and the other two liquid ejection heads 2 are conveyed. One of the three liquid ejection heads 2 is arranged at a position shifted along the direction. The liquid discharge heads 2 are arranged so that the printable range of each liquid discharge head 2 is connected in the width direction of the print paper P (in the direction intersecting the conveyance direction of the print paper P) or the ends overlap. Thus, printing without gaps in the width direction of the printing paper P is possible.

The four head groups 72 are arranged along the conveyance direction of the recording paper P. A liquid, for example, ink is supplied to each liquid ejection head 2 from a liquid tank (not shown). The liquid discharge heads 2 belonging to one head group 72 are supplied with the same color ink, and the four head groups 72 can print four color inks. The colors of ink ejected from each head group 72 are, for example, magenta (M), yellow (Y), cyan (C), and black (K). A color image can be printed by printing such ink under the control of the control unit 88.

The number of liquid discharge heads 2 mounted on the printer 1 may be one if it is a single color and the range that can be printed by one liquid discharge head 2 is printed. The number of liquid ejection heads 2 included in the head group 72 and the number of head groups 72 can be changed as appropriate according to the printing target and printing conditions. For example, the number of head groups 72 may be increased in order to perform multicolor printing. Also, if a plurality of head groups 72 that print in the same color are arranged and printed alternately in the transport direction, the transport speed can be increased even if the liquid ejection heads 2 having the same performance are used. Thereby, the printing area per time can be increased. Alternatively, a plurality of head groups 72 for printing in the same color may be prepared and arranged so as to be shifted in a direction crossing the transport direction, so that the resolution in the width direction of the print paper P may be increased.

Furthermore, in addition to printing colored inks, a liquid such as a coating agent may be printed for surface treatment of the printing paper P.

The printer 1 performs printing on the printing paper P that is a recording medium. The printing paper P is wound around the paper feed roller 80A, passes between the two guide rollers 82A, passes through the lower side of the liquid ejection head 2 mounted on the frame 70, and thereafter It passes between the two conveying rollers 82B and is finally collected by the collecting roller 80B. When printing, the printing paper P is transported at a constant speed by rotating the transport roller 82 </ b> B and printed by the liquid ejection head 2. The collection roller 80B winds up the printing paper P sent out from the conveyance roller 82B. The conveyance speed is, for example, 50 m / min. Each roller may be controlled by the controller 88 or may be manually operated by a person.

The recording medium may be a roll-like cloth other than the printing paper P. Further, instead of directly transporting the printing paper P, the printer 1 may transport the transport belt directly and transport the recording medium placed on the transport belt. By doing so, sheets, cut cloth, wood, tiles and the like can be used as the recording medium. Furthermore, a wiring pattern of an electronic device may be printed by discharging a liquid containing conductive particles from the liquid discharge head 2. Still further, the chemical may be produced by discharging a predetermined amount of liquid chemical agent or liquid containing the chemical agent from the liquid discharge head 2 toward the reaction container or the like and reacting.

In addition, a position sensor, a speed sensor, a temperature sensor, and the like may be attached to the printer 1, and the control unit 88 may control each part of the printer 1 according to the state of each part of the printer 1 that can be understood from information from each sensor. . For example, the temperature of the liquid discharge head 2, the temperature of the liquid in the liquid tank, the pressure applied by the liquid in the liquid tank to the liquid discharge head 2, etc. affect the discharge characteristics such as the discharge amount and discharge speed of the discharged liquid. In the case of giving, the drive signal for ejecting the liquid may be changed according to the information.

Next, the liquid discharge head 2 according to an embodiment of the present invention will be described. FIG. 2A is a plan view showing a head main body 2a which is a main part of the liquid ejection head 2 shown in FIG. FIG. 2B is a plan view showing a state in which the second flow path member 6 is removed from the head main body 2a. 3 and 4 are enlarged plan views of FIG. 2 (b). FIG. 5A is a longitudinal sectional view taken along the line VV in FIG. FIG. 5B is a partial longitudinal sectional view along the first common flow path 20 in the vicinity of the opening 20 a of the first common flow path 20 of the head main body 2 a.

Each figure is drawn as follows to make it easy to understand. In FIGS. 2 to 4, the flow path and the like that should be drawn with a broken line below other objects are drawn with a solid line. In FIG. 2A, the flow path in the first flow path member 4 is omitted, and only the arrangement of the individual electrode main body 44a is shown.

The liquid discharge head 2 may include a metal casing, a driver IC, a wiring board and the like in addition to the head main body 2a. In addition, the head body 2a includes a first flow path member 4, a second flow path member 6 that supplies liquid to the first flow path member 4, and a piezoelectric actuator in which a displacement element 50 that is a pressurizing unit is built. And a substrate 40. The head body 2a has a flat plate shape that is long in one direction, and this direction is sometimes referred to as a longitudinal direction. Further, the second flow path member 6 serves as a support member, and the head body 2 a is fixed to the frame 70 at both ends in the longitudinal direction of the second flow path member 6.

The first flow path member 4 constituting the head body 2a has a flat plate shape and a thickness of about 0.5 to 2 mm. On the pressurizing chamber surface 4-1, which is the first main surface of the first flow path member 4, a number of pressurizing chambers 10 are arranged side by side in the plane direction. On the discharge hole surface 4-2, which is the second main surface of the first flow path member 4 and on the opposite side of the pressurizing chamber surface 4-1, the discharge holes 8 for discharging the liquid are arranged in the plane direction. Many are arranged side by side. Each discharge hole 8 is connected to the pressurizing chamber 10. In the following description, it is assumed that the pressurizing chamber surface 4-1 is located above the discharge hole surface 4-2.

In the first flow path member 4, a plurality of first common flow paths 20 and a plurality of second common flow paths 24 are arranged so as to extend along the first direction. Moreover, the 1st common flow path 20 and the 2nd common flow path 24 are located in a line in the 2nd direction which is a direction which cross | intersects a 1st direction alternately. The second direction is the same direction as the longitudinal direction of the head body 2a.

The pressurizing chambers 10 are arranged along both sides of the first common flow path 20 and constitute one pressurization chamber row 11A, one row on each side. The first common flow path 20 and the pressurizing chambers 10 arranged on both sides of the first common flow path 20 are connected via a first individual flow path 12.

The pressurizing chambers 10 are arranged along both sides of the second common flow path 24, and the pressurizing chamber row 11A is constituted by one row on each side for a total of two rows. The second common flow path 24 and the pressurizing chambers 10 arranged on both sides thereof are connected via the second individual flow path 14. Hereinafter, the first common channel 20 and the second common channel 24 may be collectively referred to as a common channel.

With the configuration as described above, in the first flow path member 4, the liquid supplied to the first common flow path 20 flows into the pressurizing chambers 10 arranged along the first common flow path 20, and partly The other liquid is discharged from the discharge hole 8, and the other part of the liquid flows into the second common flow path 24 located on the opposite side of the first common flow path 20 with respect to the pressurizing chamber 10. It is discharged from the one flow path member 4 to the outside.

By arranging the second common channel 24 on both sides of the first common channel 20 and the first common channel 20 on both sides of the second common channel 24, one pressurizing chamber row 11A is provided. One first common flow path 20 and one second common flow path 24 are connected, and another first common flow path 20 and another second common flow path with respect to another pressurization chamber row 11A. Compared with the case where 24 is connected, the number of the 1st common flow path 20 and the 2nd common flow path 24 can be made into about half, and it is preferable. Since the number of first common channels 20 and second common channels 24 is small, the number of pressurizing chambers 10 is increased to increase the resolution, or the first common channel 20 and the second common channel 24 are thickened. Thus, the difference in ejection characteristics from the ejection holes 8 can be reduced, and the size of the head body 2a in the planar direction can be reduced.

The pressure applied to the portion of the first individual flow path 12 on the first common flow path 20 side connected to the first common flow path 20 is affected by the pressure loss, so that the first individual flow path 12 is added to the first common flow path 20. Varies depending on the position where the two are connected (mainly the position in the first direction). The pressure applied to the portion on the second individual flow path 14 side connected to the second common flow path 24 is the position where the second individual flow path 14 is connected to the second common flow path 24 due to the effect of pressure loss (main Depending on the position in the first direction. If the opening 20a to the outside of the first common channel 20 is arranged at one end in the first direction, and the opening 24a to the outside of the second common channel 24 is arranged at the other end in the first direction. The pressure difference due to the arrangement of the first individual flow paths 12 and the second individual flow paths 14 is canceled out, and the pressure difference applied to the discharge holes 8 can be reduced. Note that both the opening 20a of the first common channel 20 and the opening 24a of the second common channel 24 open to the pressurizing chamber surface 4-1.

The liquid meniscus is held in the discharge hole 8 in a state where the liquid is not discharged. Since the surface tension of the liquid tries to reduce the surface area of the liquid, the meniscus can be held if the pressure is small even if it is a positive pressure. If the positive pressure increases, the liquid overflows, and if the negative pressure increases, the liquid is drawn into the first flow path member 4, and the liquid cannot be discharged. For this reason, it is necessary to prevent the difference in the pressure of the liquid in the discharge hole 8 from becoming too large when the liquid flows from the first common flow path 20 to the second common flow path 24.

The pressurizing chamber 10 is disposed facing the pressurizing chamber surface 4-1, and includes a pressurizing chamber main body 10a that receives pressure from the displacement element 50, and a discharge hole surface 4- from below the pressurizing chamber main body 10a. 2 is a hollow region including a descender 10b, which is a partial flow path connected to the discharge hole 8 opened in FIG. The pressurizing chamber body 10a has a right circular cylinder shape, and the planar shape is a circular shape. Since the planar shape is circular, the displacement amount when the displacement element 50 is deformed with the same force and the volume change of the pressurizing chamber 10 caused by the displacement can be increased. The descender 10b has a right circular cylinder shape whose diameter is smaller than that of the pressurizing chamber body 10a, and has a circular cross-sectional shape. The descender 10b is housed in the pressurizing chamber body 10a when viewed from the pressurizing chamber surface 4-1. The descender 10b may have a conical shape or a trapezoidal conical shape whose sectional area decreases toward the discharge hole 8 side. Since the cross-sectional shape of the descender 10b is smaller than that of the pressurizing chamber main body 10a, the widths of the first common channel 20 and the second common channel 24 can be increased correspondingly, and the above-described pressure loss difference can be decreased.

The plurality of pressurizing chambers 10 constitute a plurality of pressurizing chamber rows 11A along the first direction, and a plurality of pressurizing chamber rows 11B along the second direction that intersects the first direction. Is configured. Each discharge hole 8 is located at the center of the corresponding pressurizing chamber 10. Similarly to the pressurizing chamber 10, the plurality of discharge holes 8 constitute a plurality of discharge hole rows 9A along the first direction and a plurality of discharge hole rows 9B along the second direction. Yes.

In the present embodiment, the first common flow path 20 has 50 lines, the second common flow path 24 has 51 lines, and the pressurizing chamber line 11A and the discharge hole line 9A have 100 lines. One pressurization chamber row 11A includes 16 pressurization chambers 10, and one discharge hole row 9A includes 16 discharge holes 8. That is, the pressurizing chamber row 11B has 16 rows, and the discharge hole row 9B has 16 rows.

In the adjacent pressurizing chamber row 11A, it is preferable to displace the pressurizing chambers 10 in the first direction in a zigzag manner because the distance between the pressurizing chambers 10 belonging to the adjacent pressurizing chamber row 11A can be increased. In that case, the pressurizing chamber row 11B has 32 rows, and the discharge hole row 9B has 32 rows.

The angle formed by the first direction and the second direction is deviated from a right angle. For this reason, the ejection holes 8 belonging to the ejection hole array 9A arranged along the first direction are displaced in the second direction by an angle shifted from the right angle. And since the discharge hole row | line 9A is arrange | positioned along with the 2nd direction, the discharge hole 8 which belongs to the different discharge hole row | line | column 9A is shifted | deviated and arranged in the 2nd direction by that amount. Together, the discharge holes 8 of the first flow path member 4 are arranged at regular intervals in the second direction, so that a predetermined range is filled with pixels formed by the discharged liquid. Can print.

In FIG. 3, when the discharge holes 8 are projected in a direction orthogonal to the second direction, 32 discharge holes 8 are projected in the range of the virtual straight line R, and the discharge holes 8 are arranged at intervals of 360 dpi in the virtual straight line R. . Accordingly, if the printing paper P is conveyed and printed in a direction orthogonal to the virtual straight line R, printing can be performed with a resolution of 360 dpi. The ejection holes 8 projected in the virtual straight line R belong to all (16) ejection holes 8 belonging to one ejection hole array 9A and to two ejection hole arrays 9A located on both sides of the ejection hole array 9A. Half of the discharge holes 8 (eight). In order to obtain such a configuration, the discharge holes 8 are arranged at intervals of 22.5 dpi in each discharge hole row 9B. This is because 360/16 = 22.5. The first common flow path 20 and the second common flow path 24 are straight in the range where the discharge holes 8 are arranged on a straight line, and are shifted in parallel between the discharge holes 8 where the straight lines are shifted. In the 1st common flow path 20 and the 2nd common flow path 24, since there are few shift parts, flow resistance is small. Further, since the portion that is shifted in parallel is arranged at a position that does not overlap with the pressurizing chamber 10, it is possible to reduce the variation in discharge characteristics for each pressurizing chamber 10.

The pressurizing chambers 10 belonging to the pressurizing chamber row 11B located at both ends in the second direction are dummy pressurizing chambers. The first common channel 20 or the second common channel 24 is provided on the end side in the second direction with respect to the dummy pressurizing chamber. If the second common channel 24 is disposed on the center side in the second direction with respect to the dummy pressurizing chamber, the disposed channel becomes the first common channel 20 and is disposed in the dummy pressurizing chamber. On the other hand, if the first common flow path 20 is disposed on the center side in the second direction, the second common flow path 24 is obtained. Similarly to the normal pressurizing chamber 10, the dummy pressurizing chamber is also connected to the first common channel 20 via the first individual channel 12, and the second common channel via the second individual channel 14. 24 is connected.

The common flow channel located at the end in the second direction is either the first common flow channel 20 or the second common flow channel 24, and the pressurized chamber row 11A to be supplied or recovered becomes one row, and therefore There is a possibility that the discharge characteristics of the discharge from the pressurization chambers 10 belonging to the one pressurization chamber row 11 </ b> A vary with respect to the discharge characteristics from the other pressurization chambers 10. Therefore, the pressurizing chambers 10 belonging to the pressurizing chamber row 11A are dummy pressurizing chambers that are not used for printing. The dummy pressurizing chamber has the same basic shape as the normal pressurizing chamber 10, and the discharge hole 8 may not be disposed on the discharge hole surface 4-2 side, or the discharge hole 8 may be disposed. Good.

As described above, if the pressurizing chamber 10 belonging to the pressurizing chamber row 11A located at both ends in the second direction is a dummy pressurizing chamber, the pressurizing chamber row 11A located second from both ends in the second direction is used. The first common flow path 20 for supplying the liquid to the pressure chamber 10 to which it belongs supplies liquid to the two pressure chamber rows 11A in the same manner as other normal first common flow paths 20. In addition, the second common flow path 24 for recovering the liquid in the pressurization chamber 10 belonging to the pressurization chamber row 11A located second from both ends in the second direction is the same as other normal second common flow paths 24. The liquid in the two rows of pressurizing chambers 11A is collected. For this reason, a difference in ejection characteristics is less likely to occur.

Of the discharge holes 8 belonging to the discharge hole row 9A located second from the end in the second direction, the eight discharge holes 8 close to the end in the second direction are not 360 dpi apart. The discharge hole 8 is not provided at that position, and the pressurizing chamber 10 at the corresponding position may be a dummy pressurizing chamber.

The second flow path member 6 is joined to the pressurizing chamber surface 4-1 of the first flow path member 4, and has a first common flow path 22 for supplying a liquid to the first common flow path 20 and a second common flow path. And a second integrated flow path 26 for recovering the liquid in the flow path 24. The thickness of the second flow path member 6 is thicker than that of the first flow path member 4 and is about 5 to 30 mm.

The second flow path member 6 is joined in a region where the piezoelectric actuator substrate 40 of the pressure chamber surface 4-1 of the first flow path member 4 is not connected. More specifically, the piezoelectric actuator substrate 40 is joined so as to surround it. By doing in this way, it can suppress that a part of discharged liquid adheres to the piezoelectric actuator board | substrate 40 as mist. In addition, since the first flow path member 4 is fixed on the outer periphery, it is possible to suppress the first flow path member 4 from vibrating due to the driving of the displacement element 50 and causing resonance or the like.

In addition, the second flow path member 6 has a through hole 6c extending vertically. The through hole 6c is passed through a signal transmission unit such as FPC (Flexible Printed Circuit) that transmits a drive signal for driving the piezoelectric actuator substrate 40. The first flow path member 4 side of the through hole 6c is a widened portion 6ca having a wide width in the short direction, and a signal transmission portion extending from the piezoelectric actuator substrate 40 to both sides in the short direction is It is bent by the widened portion 6 ca and goes upward, and passes through the through hole 6. In addition, since the convex part of the part which spreads in the wide part 6ca may damage a signal transmission part, it is preferable to make it R shape.

By disposing the first integrated flow path 22 in the second flow path member 6 which is different from the first flow path member 4 and is thicker than the first flow path member 4, the cross-sectional area of the first integrated flow path 22 is increased. Accordingly, a difference in pressure loss due to a difference in position where the first integrated flow path 22 and the first common flow path 20 are connected can be reduced. The channel resistance of the first integrated channel 22 is preferably 1/100 or less of the first common channel 20. Here, the channel resistance of the first integrated channel 22 is more precisely the channel resistance in the range connected to the first common channel 20 in the first integrated channel 22.

By disposing the second integrated flow path 26 in the second flow path member 6 that is different from the first flow path member 4 and is thicker than the first flow path member 4, the cross-sectional area of the second integrated flow path 26 is increased. Accordingly, the difference in pressure loss due to the difference in the position where the second integrated channel 26 and the second common channel 24 are connected can be reduced. The channel resistance of the second integrated channel 26 is preferably set to 1/100 or less of the second common channel 24. Here, the channel resistance of the second integrated channel 26 is more precisely the channel resistance in the range connected to the first integrated channel 22 in the second integrated channel 26.

The first integrated flow path 22 is disposed at one end of the second flow path member 6 in the short direction, the second integrated flow path 26 is disposed at the other end of the second flow path member 6 in the short direction, Each of the flow paths is directed to the first flow path member 4 side so as to be connected to the first common flow path 20 and the second common flow path 24, respectively. With such a structure, the cross-sectional areas of the first integrated flow path 22 and the second integrated flow path 26 can be increased, and the flow path resistance can be decreased. Moreover, since the outer periphery is fixed by the 2nd flow path member 6 by setting it as such a structure, the 1st flow path member 4 can make rigidity high. Furthermore, with such a structure, the through hole 6c through which the signal transmission unit passes can be provided.

The second flow path member 6 is configured by laminating

plates

6a and 6b of the second flow path member. On the upper surface of the plate 6b, a groove serving as a first integrated flow path body 22a, which is a portion of the first integrated flow path 22 extending in the second direction and having a low flow resistance, and a second integrated flow path 26 A groove serving as a second integrated flow path body 26a, which is a portion having a low flow resistance extending in the second direction, is disposed.

A plurality of first connection flow paths 22b extend downward (in the direction of the first flow path member 4) from the groove serving as the first integrated flow path body 22a, and open on the pressurizing chamber surface 4-1. Connected to the opening 20a of the first common flow path. The first connection flow paths 22b are separated by a partition 6ba (that is, the first common flow path 20 side of the first connection flow paths 22b is branched). Thereby, the rigidity of the connection between the second flow path member 6 and the first flow path member 4 can be increased. Furthermore, in the second direction, the length of the partition 6ba is longer than the length of the first connection channel 22b, so that the rigidity of the connection between the second channel member 6 and the first channel member 4 is further increased. Can be high.

A plurality of second connection flow paths 26b extend downward (in the direction of the first flow path member 4) from the groove serving as the second integrated flow path body 26a, and open on the pressurizing chamber surface 4-1. Connected to the opening 24a of the second common flow path. Each second connection flow path 26b is partitioned by a partition 6bb (that is, the second common flow path 24 side of the second connection flow path 26b is branched). Thereby, the rigidity of the connection between the second flow path member 6 and the first flow path member 4 can be increased. Furthermore, in the second direction, the length of the partition 6bb is longer than the length of the second connecting flow path 26b, so that the rigidity of the connection between the second flow path member 6 and the first flow path member 4 is further increased. Can be high.

The plate 6a is provided with

openings

22c and 22d at both ends in the second direction of the first integrated flow path 22, respectively. The plate 6 a is provided with

openings

26 c and 26 d at both ends in the second direction of the second integrated flow channel 26. When supplying a liquid to the liquid discharge head 2 that does not contain liquid, the liquid is supplied from one opening (for example, the opening 22c) so that the liquid in the first integrated flow path 22 is easily discharged to the outside. While supplying the liquid to the flow path member 4 and discharging the air and the overflowing liquid from another opening (for example, 22d), it is possible to make it difficult for the gas to enter the first flow path member 4. Similarly, the second integrated channel 26 may be configured such that liquid is supplied from one opening (for example, the opening 26c) and liquid is discharged from the other opening (for example, the opening 26d).

There are several methods for supplying and collecting liquid when printing. One is that all of the liquid supplied to the first integrated flow path 22 enters the first flow path member 4 and further enters the second integrated flow path 26 and is discharged to the outside. At this time, no liquid is supplied to the second integrated flow channel 26 from the outside. In this case, the liquid is supplied from the two

openings

22c and 22d and recovered from the two

openings

26c and 26d, the liquid is supplied from one of the

openings

22c and 22d, the other is closed, and the opening 26c is closed. 26d, there is a method in which the liquid is recovered from one of them and the other is closed, and there is a method in which the combination of the two is reversed. In order to reduce the difference in pressure due to pressure loss, it is preferable to supply from two openings and collect from two openings. However, connection of a tube for supplying and discharging liquid and control of pressure become complicated. Supplying from one opening and collecting from one opening simplifies connection and control of pressure. In that case, it is preferable that the supply and the recovery are performed in pairs with the openings at positions opposite to each other in the second direction because the influence of the pressure loss is offset. Specifically, it may be supplied from the opening 22c and recovered from the opening 26d, or supplied from the opening 22d and recovered from the opening 26c.

Another method of supplying and discharging is to supply the liquid from one opening (for example, 22c) of the first integrated flow path 22, collect the liquid from the other opening (for example, 22d), and to open one opening ( For example, liquid is supplied from 26d) and recovered from the other opening (for example, 26c). If the pressure of each supply / discharge is adjusted so that the pressure of the first integrated flow path 22 is higher than the pressure of the second integrated flow path 26, the liquid flows through the first flow path member 4. . In this way, the difference in pressure applied to the meniscus of each discharge hole 8 is the smallest.

The above-described two methods may be combined to supply / discharge the first integrated flow path 22 and only recover from the second integrated flow path 26. Conversely, only the first integrated flow path 22 may be supplied, and the second integrated flow path 26 may be supplied and discharged.

Furthermore, the relationship between supply and recovery described above may be reversed. For example, the liquid may be supplied from both of the two

openings

26 c and 26 d of the second integrated flow path 26, and the liquid may be recovered from both of the two

openings

22 c and 22 d of the second discharge flow path 22.

A damper may be provided in the first integrated flow path 22 and the second integrated flow path 26 so that the supply or discharge of the liquid is stabilized against fluctuations in the discharge amount of the liquid. Further, by providing a filter in the first integrated flow path 22 and the second integrated flow path 26, foreign substances and bubbles may be difficult to enter the first flow path member 4.

A piezoelectric actuator substrate 40 including a displacement element 50 is bonded to the pressurizing chamber surface 4-1, which is the upper surface of the first flow path member 4, so that each displacement element 50 is positioned on the pressurizing chamber 10. Has been placed. The piezoelectric actuator substrate 40 occupies a region having substantially the same shape as the pressurizing chamber group formed by the pressurizing chamber 10. Further, the opening of each pressurizing chamber 10 is closed by bonding the piezoelectric actuator substrate 40 to the pressurizing chamber surface 4-1 of the flow path member 4. The piezoelectric actuator substrate 40 has a rectangular shape that is long in the same direction as the head body 2a. The piezoelectric actuator substrate 40 is connected to a signal transmission unit such as an FPC for supplying a signal to each displacement element 50. The second flow path member 6 is provided with a through hole 6c penetrating vertically at the center, and the signal transmission unit is electrically connected to the control unit 88 through the through hole 6c. The signal transmission unit has a shape extending in the short direction from one long side end of the piezoelectric actuator substrate 40 toward the other long side end, and the wiring disposed in the signal transmission unit extends along the short direction. Extending and arranging in the longitudinal direction is preferable because the distance between the wirings can be easily increased.

Individual electrodes 44 are respectively arranged at positions facing the pressurizing chambers 10 on the upper surface of the piezoelectric actuator substrate 40.

The flow path member 4 has a laminated structure in which a plurality of plates are laminated. These plates are a cavity plate 4a, a supply plate 4b, manifold plates 4c to e, a recovery plate 4f and a nozzle plate 4g in this order from the pressurizing chamber surface 4-1 side of the flow path member 4. Many holes and grooves are formed in these plates. For example, the holes and grooves can be formed by etching each plate made of metal. Since the thickness of each plate is about 10 to 300 μm, the formation accuracy of the holes to be formed can be increased. The manifold plates 4c to 4e have the same shape and may be configured by one plate, but are configured by three plates in order to form the holes with high accuracy. Each plate is aligned and stacked such that these holes communicate with each other to form a flow path such as the first common flow path 20.

The pressurizing chamber main body 10a is opened on the pressurizing chamber surface 4-1 of the flat plate-like channel member 4, and the piezoelectric actuator substrate 40 is joined thereto. The pressurizing chamber surface 4-1 has an opening 20 a for supplying a liquid to the first common flow path 20 and an opening 24 a for recovering the liquid from the second common flow path 24. A discharge hole 8 is opened in a discharge hole surface 4-2 on the opposite side of the pressure chamber surface 4-1 of the flow path member 4.

There are a pressurizing chamber 10 and a discharge hole 8 as a structure for discharging the liquid. The pressurizing chamber 10 includes a pressurizing chamber main body 10a facing the displacement element 50 and a descender 10b having a smaller sectional area than the pressurizing chamber main body 10a. The pressurizing chamber main body 10a is formed in the cavity plate 4a, and the descender 10b is overlapped with holes formed in the plates 4b to 4f, and is further blocked by the nozzle plate 4g (parts other than the discharge holes 8). It is made up of.

The first individual channel 12 is connected to the pressurizing chamber body 10 a, and the first individual channel 12 is connected to the first common channel 20. The first individual flow path 12 is a circular hole that penetrates the supply plate 4b, and the liquid flows in the vertical direction. The first common flow path 20 is formed by overlapping holes formed in the plates 4c to 4e, and is further closed by the supply plate 4b on the upper side and the nozzle plate 4g on the lower side.

The descender 10 b is connected to the second individual flow path 14, and the second individual flow path 14 is connected to the second common flow path 24. The second individual flow path 14 is a through groove penetrating the recovery plate 4f, and the liquid flows along the groove. The second common flow path 24 is formed by overlapping holes formed in the plates 4c to 4h, and is further closed by the supply plate 4b on the upper side and the nozzle plate 4g on the lower side.

Regarding the liquid flow, the liquid supplied to the first integrated flow path 22 enters the pressurizing chamber 10 through the first common flow path 20 and the first individual flow path 12 in order, and a part of the liquid flows. It is discharged from the discharge hole 8. The liquid that has not been discharged passes through the second individual flow path 14, enters the second common flow path 24, enters the second integrated flow path 26, and is discharged outside the head body 2.

The piezoelectric actuator substrate 40 has a laminated structure composed of two piezoelectric ceramic layers 40a and 40b that are piezoelectric bodies. Each of these piezoelectric ceramic layers 40a and 40b has a thickness of about 20 μm. That is, the thickness from the upper surface of the piezoelectric ceramic layer 40a of the piezoelectric actuator substrate 40 to the lower surface of the piezoelectric ceramic layer 40b is about 40 μm. The thickness ratio between the piezoelectric ceramic layer 40a and the piezoelectric ceramic layer 40b is set to 3: 7 to 7: 3, preferably 4: 6 to 6: 4. Both of the piezoelectric ceramic layers 40 a and 40 b extend so as to straddle the plurality of pressure chambers 10. The piezoelectric ceramic layers 40a, 40b may, for example, strength with a dielectric, lead zirconate titanate (PZT), NaNbO ₃ system, BaTiO ₃ system, (BiNa) NbO ₃ system, such as BiNaNb ₅ O ₁₅ system Made of ceramic material.

The piezoelectric actuator substrate 40 has a common electrode 42 made of a metal material such as Ag—Pd and an individual electrode 44 made of a metal material such as Au. The common electrode 42 has a thickness of about 2 μm, and the individual electrode 44 has a thickness of about 1 μm.

The individual electrodes 44 are disposed at positions facing the pressurizing chambers 10 on the upper surface of the piezoelectric actuator substrate 40, respectively. The individual electrode 44 has a planar shape slightly smaller than that of the pressurizing chamber main body 10a and has a shape substantially similar to the pressurizing chamber main body 10a, and an extraction electrode drawn from the individual electrode main body 44a. 44b. A connection electrode 46 is formed at a portion of one end of the extraction electrode 44 b that is extracted outside the region facing the pressurizing chamber 10. The connection electrode 46 is a conductive resin containing conductive particles such as silver particles, and is formed with a thickness of about 5 to 200 μm. The connection electrode 46 is electrically joined to an electrode provided in the signal transmission unit.

Although details will be described later, a drive signal is supplied to the individual electrode 44 from the control unit 88 through the signal transmission unit. The drive signal is supplied in a constant cycle in synchronization with the conveyance speed of the print medium P.

The common electrode 42 is formed over substantially the entire surface in the region between the piezoelectric ceramic layer 40a and the piezoelectric ceramic layer 40b. That is, the common electrode 42 extends so as to cover all the pressurizing chambers 10 in the region facing the piezoelectric actuator substrate 40. The common electrode 42 is a through conductor formed by penetrating the piezoelectric ceramic layer 40a on a common electrode surface electrode (not shown) formed on the piezoelectric ceramic layer 40a so as to avoid the electrode group composed of the individual electrodes 44. Are connected through. Further, the common electrode 42 is grounded via the common electrode surface electricity and held at the ground potential. Similar to the individual electrode 44, the common electrode surface electrode is directly or indirectly connected to the controller 88.

A portion sandwiched between the individual electrode 44 and the common electrode 42 of the piezoelectric ceramic layer 40 a is polarized in the thickness direction, and becomes a unimorph-structured displacement element 50 that is displaced when a voltage is applied to the individual electrode 44. Yes. More specifically, when an electric field is applied in the polarization direction to the piezoelectric ceramic layer 40a by setting the individual electrode 44 to a potential different from that of the common electrode 42, an active portion where the electric field is applied is distorted by the piezoelectric effect. Work as. In this configuration, when the individual electrode 44 is set to a predetermined positive or negative potential with respect to the common electrode 42 by the control unit 88 so that the electric field and the polarization are in the same direction, a portion sandwiched between the electrodes of the piezoelectric ceramic layer 40a. (Active part) contracts in the surface direction. On the other hand, the piezoelectric ceramic layer 40b, which is an inactive layer, is not affected by an electric field, so that it does not spontaneously shrink and attempts 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 40a and the piezoelectric ceramic layer 40b, and the piezoelectric ceramic layer 40b is deformed so as to be convex toward the pressurizing chamber 10 (unimorph deformation).

Subsequently, the liquid discharge operation will be described. The displacement element 50 is driven (displaced) by a drive signal supplied to the individual electrode 44 through a driver IC or the like under the control of the control unit 88. In the present embodiment, liquid can be ejected by various driving signals. Here, a so-called strike driving method will be described.

The individual electrode 44 is set to a potential higher than the common electrode 42 (hereinafter referred to as a high potential) in advance, and the individual electrode 44 is once set to the same potential as the common electrode 42 (hereinafter referred to as a low potential) every time there is a discharge request. Thereafter, the potential is set again at a predetermined timing. Thereby, at the timing when the individual electrode 44 becomes low potential, the piezoelectric ceramic layers 40a and 40b return to the original (flat) shape (begin), and the volume of the pressurizing chamber 10 is in the initial state (the potentials of both electrodes are different) Increase compared to the state). As a result, a negative pressure is applied to the liquid in the pressurizing chamber 10. Then, the liquid in the pressurizing chamber 10 starts to vibrate with the natural vibration period. Specifically, first, the volume of the pressurizing chamber 10 begins to increase, and the negative pressure gradually decreases. Next, the volume of the pressurizing chamber 10 becomes maximum and the pressure becomes almost zero. Next, the volume of the pressurizing chamber 10 begins to decrease, and the pressure increases. Thereafter, the individual electrode 44 is set to a high potential at a timing at which the pressure becomes substantially maximum. Then, the first applied vibration overlaps with the next applied vibration, and a larger pressure is applied to the liquid. This pressure propagates through the descender and discharges the liquid from the discharge hole 8.

That is, a droplet can be ejected by supplying to the individual electrode 44 a pulse driving signal that is set to a low potential for a certain period of time with reference to a high potential. If this pulse width is AL (Acoustic Length), which is half of the natural vibration period of the liquid in the pressurizing chamber 10, in principle, the liquid discharge speed and amount can be maximized. The natural vibration period of the liquid in the pressurizing chamber 10 is greatly influenced by the physical properties of the liquid and the shape of the pressurizing chamber 10, but besides that, the physical properties of the piezoelectric actuator substrate 40 and the flow path connected to the pressurizing chamber 10 Also affected by the characteristics of.

Note that the pulse width is actually set to a value of about 0.5 AL to 1.5 AL because there are other factors to consider, such as combining the ejected droplets into one. Further, since the discharge amount can be reduced by setting the pulse width to a value outside of AL, the pulse width is set to a value outside of AL in order to reduce the discharge amount.

The arrangement of the discharge holes 8 of the present invention will be described. FIG. 6 shows the arrangement of the discharge holes 8 according to an embodiment of the present invention. In FIG. 6, the positions where the discharge holes 8 exist are filled in the squares divided into rows and columns so that the positions of the discharge holes 8 on the rows and columns can be easily understood. In the following description, the position of the xth column and the yth row may be represented as (x, y). The first direction and the second direction shown in FIG. 6 are the same as the first direction and the second direction shown in FIG. In FIG. 6, since the enlargement ratio is different between the vertical direction and the horizontal direction in the figure, and the enlargement ratio in the horizontal direction is large, the angle formed by the first direction and the second direction is different from FIG. Looks like.

The discharge holes 8 are arranged on 16 rows along the second direction. That is, the discharge holes 8 constitute 16 discharge hole rows 9B. In each discharge hole row 9B, the discharge holes 8 are arranged at the same interval in the second direction. Furthermore, the discharge holes 8 are also arranged at the same interval in the second direction in the entire discharge hole 8, and the interval is 1/16 of the interval in each discharge hole row 9B.

The discharge hole row 9B is a row in which the discharge holes 8 are arranged at equal intervals in the second direction. Actually, the discharge hole row 9B is further connected with discharge holes 8 on the left and right in FIG. There are 16 discharge hole rows 9B, which are arranged in the first direction. Called the first row, the second row,..., The 16th row in the order arranged in the first direction. In the above-described embodiment, the distance between the discharge hole rows 9B is the same, but this is not necessarily required. When the distances between the respective discharge hole rows 9B are different, it is necessary to understand in the following description using a figure reduced in a state where the ratio is maintained.

Recording is performed while moving the recording medium in the short direction of the head body 2a. The liquid that lands on the recording medium adjacent to the second direction is discharged from the discharge holes 8 adjacent to each other in the second direction. That is, the liquid ejected from the ejection holes 8 in the adjacent rows becomes the adjacent pixels on the recording medium.

In order to increase the recording accuracy, the liquid ejection head 2 is installed so that the conveyance direction of the recording medium and the second direction are orthogonal to each other, but in reality, a certain degree of angular deviation occurs. When there is an angle shift, the distance shift between adjacent pixels is proportional to the angle of the shift and the distance in the short direction of the head body 2a of the ejection hole 8 that ejected those pixels. For this reason, when the discharge holes 8 adjacent to each other in the row direction are arranged away from each other in the short side direction, the shift in the distance between the pixels becomes large.

Further, the discharge holes 8 are arranged side by side in the first direction and constitute a discharge hole row 9A. Further, a pressurizing chamber row 11A in which the pressurizing chambers 10 are arranged along the discharge hole row 9A is configured. The first common flow path 20 and the second common flow path 24 are disposed between the pressurizing chamber rows 11A along the pressurizing chamber row 11A. Since the first common flow path 20 and the second common flow path 24 supply the liquid required for ejection and it is necessary to allow the liquid to flow so that the solid content of the ink does not easily settle down. The cross-sectional area is required. Even if the head body 2a does not circulate and does not have the second common flow path 24, it is necessary to supply the liquid to be discharged, and the cross-sectional area of the first common flow path 20 needs to be more than a certain level. is there.

When the angle of the first direction with respect to the second direction becomes small, the first common flow path 20 and the second common flow path 24 obliquely cross the head body 2a, and the cross-sectional area becomes small. In order to increase the cross-sectional area, for example, it is conceivable to arrange the discharge holes 8 at positions (1, 1), (2, 2),... (16, 16). However, in such an arrangement, (16, 16) in the row direction is next to (17, 1), and the arrangement is 15 units away in the short direction. Such an arrangement is the most distant arrangement in the 16-row ejection hole arrangement, and the influence of the installation angle deviation of the head body 2a becomes large.

Therefore, instead of returning directly from the 16th line to the 1st line, the discharge holes 8 are arranged between them. In FIG. 6, the discharge holes belonging to the second array 9A-2 are arranged between the second discharge holes 8-2 (46, 16) and the third discharge holes 8-3 (49, 1) in the second direction. 8 (47, 8) and discharge holes 8 (48, 9) are present. Accordingly, the distance in the short direction between the second discharge hole 8-2 (46, 16) and the discharge hole 8 (47, 8) is 8 units, and the discharge hole 8 (48, 9) and the third discharge hole 8- The distance in the short direction from 3 (49, 1) is 8 units, which is about a half of the distance as compared with the arrangement described above. Thereby, compared with the arrangement described above, the influence on the angle deviation is approximately halved. In addition, since the angle of the first direction with respect to the second direction is not so small, the cross-sectional areas of the first common channel 20 and the second common channel 24 can be increased.

The arrangement of the discharge holes 8 is as follows. Attention is paid to one discharge hole 8 belonging to the first row, which is defined as a first discharge hole 8-1 (33, 1). Among the discharge holes 8 belonging to the 16th line, the discharge hole 8-A (30, 16) has the shortest distance from the first discharge hole 8-1, and the second is the second discharge hole 8-. 2 (46, 16), the third is the discharge hole 8-B (14, 16), and the fourth is the fourth discharge hole 8-4 (62, 16). The direction from the second discharge hole 8-2 toward the fourth discharge hole 8-4 coincides with the second direction. Of the discharge holes 8 belonging to the first line and positioned on the second direction side with respect to the first discharge hole 8-1, the discharge having the shortest distance from the first discharge hole 8-1. The hole 8 is referred to as a third discharge hole 8-3. Then, the first to fourth discharge holes 8-1 to 8-4 are the first discharge hole 8-1, the second discharge hole 8-2, the third discharge hole 8-3, and the fourth discharge hole in the second direction. They are arranged in the order of 8-4.

The discharge holes 8 belonging to the second to fifteenth rows are arranged in a linear discharge hole row 9A from the first discharge hole 8-1 to the fourth discharge hole 8-4. The discharge hole column 9A includes the discharge holes 8 in the 2nd to 15th rows. Further, the discharge hole array 9A has a first array 9A-1, second discharge holes 8 that are located between the first discharge holes 8-1 and the second discharge holes 8-2 in the second direction. A second array 9A-2 composed of the discharge holes 8 located between the discharge holes 8-2 and the third discharge holes 8-3, and from the third discharge holes 8-3 to the fourth discharge holes 8-4. The third array 9A-3 is composed of the discharge holes 8 positioned between them. The first array 9A-1 includes a first discharge hole 8-1, and the third array 9A-3 includes a fourth discharge hole 8-4. Further, the second discharge hole 8-2 and the third discharge hole 8-3 are arranged in a linear discharge hole array 9A from the first discharge hole 8-1 to the fourth discharge hole 8-4, which is the object here. It is not included and is included in the other discharge hole array 9A. Further, the second array 9A-2 may have only one discharge hole 8 belonging to it.

In FIG. 6, it is difficult to understand if the discharge hole array 9A, the first array 9A-1, the second array 9A-2, and the third array 9A-3 are shown with respect to the same array of the discharge holes 8. A different arrangement of the discharge holes 8 is shown.

The discharge hole rows 9A arranged as described above are arranged side by side in the second direction, so that the discharge holes can be arranged at equal intervals in the second direction. The discharge hole array 9A at the end in the second direction and the end in the direction opposite to the second direction is not perfect, but has the same shape as a part of the other discharge hole array 9A.

The above relationship is generalized when the number of ejection hole rows 9B is n rows as follows. The ejection holes 8 belonging to the 2nd to (n-1) th rows are arranged in a linear ejection hole array 9A from the first ejection holes 8-1 to the fourth ejection holes 8-4. The discharge hole column 9A includes the discharge holes 8 in the 2nd to (n-1) th rows. The discharge hole array 9A has a first array 9A-1, second discharge holes, which are formed of discharge holes 8 located between the first discharge holes 8-1 and the second discharge holes 8-2 in the second direction. The second array 9A-2 including the discharge holes 8 positioned between 8-2 and the third discharge holes 8-3, and the space between the third discharge holes 8-3 and the fourth discharge holes 8-4. The third array 9A-3 is composed of the discharge holes 8 located at the center.

The number of ejection holes 8 belonging to the 2nd to (n-1) th rows arranged in the first array 9A-1, the second array 9A-2, and the third array 9A-3 is at least one. is there. Therefore, n-1 is 4 at the minimum, and n is 5 or more.

When the position of the first discharge hole 8-1 is (1, 1), the discharge hole column 9A connected to the first discharge hole 8-1 is the m-th column of the n-th row, that is, (m, n). Considering the appropriate range for the value of m in the case where

Since the discharge hole array 9A includes n discharge holes 8, m is n or more. When m = n, the arrangement of the ejection holes 8 is, for example, (1, 1), (2, 2),... (n, n). The influence of will become large.

If the second array 9A-2 is arranged between the second discharge hole 8-2 and the third discharge hole 8-3 by setting the value of m to about 2 × n, the influence of the angular deviation is reduced and the second array 9A-2 is reduced. The cross-sectional areas of the first common channel 20 and the second common channel 24 can be increased.

When the value of m is increased to about 3 × n or more, the cross-sectional areas of the first common channel 20 and the second common channel 24 are decreased. In this case, an array such as the second array 9A-2 is arranged between the discharge holes 8 belonging to the nth discharge hole column and the discharge holes 8 belonging to the first discharge hole column in the second direction. However, in such an arrangement, the position in the short method direction is not near the center in the first direction, but at a position close to the first row discharge hole row or a position near the nth discharge hole row. If such an arrangement is used, the distance from the n-th ejection hole array or the first ejection hole array is increased, and the influence on the angular deviation is increased.

The range of n + 2 to 2 × n−1 as the value of m (n + 1 and 2 × n−1 are not included because these values are adjacent in the row direction to the discharge holes 8 belonging to the first row. Therefore, it is appropriate that it is larger than 1.5 × n and not larger than 2 × n−1. When the value of m approaches n within the range of n + 2 to 2 × n−1, the second array 9A-2 becomes longer in the second direction. When the second array 9A-2 becomes longer in the second direction, the end of the second array 9A-2 on the second discharge hole 8-2 side has a greater distance in the short direction from the second discharge hole 8-2. Then, the influence on the angle deviation gradually increases. In addition, since the angle formed between the first array 9A-1 and the second direction is gradually decreased, the difference in angle with the second array 9A-2 is increased, and the first common flow path 20 and the second common flow are increased. The cross-sectional area of the path 24 will not be constant. If the cross-sectional areas of the portions where the first individual flow path 12 and the second individual flow path 14 are connected are different, the discharge characteristics may vary. Further, if the cross-sectional areas of the first common flow path 20 and the second common flow path 24 are to be made substantially constant, the cross-sectional area must be reduced to the smallest cross section, resulting in a small cross-sectional area. In order to reduce such influence, the value of m is preferably in the range of more than 1.5 × n and 2 × n−1 or less.

In order to make the value of m within this range, the discharge hole array 9A includes the first discharge holes 8-1 among the first discharge holes 8-1 and the discharge holes 8 belonging to the nth discharge hole array 9B. The fourth discharge hole 8 may be arranged so as to be connected to the fourth to fourth, so that the discharge hole 8 is arranged as described above.

The behavior when the value of m is in the range of 2 × n + 2 to 3 × n−1 will be described later.

The entire third array 9A-3 is positioned in the first direction relative to the second array 9A-2, and the entire second array 9A-2 is positioned in the first direction relative to the first array 9A-1 It is preferable in the following points. The distance in the short direction between the second discharge holes 8-2 and the discharge holes 8 in the first array 9A-1 adjacent to the second discharge holes 8-2 in the second direction, and the second discharge holes 8-2. And the distance in the short direction from the discharge holes 8 in the first array 9A-1 adjacent in the second direction of the second discharge holes 8-2. Further, the distance in the short direction between the third discharge holes 8-3 and the discharge holes 8 in the second array 9A-2 adjacent to the second direction of the third discharge holes 8-3 can be shortened. Furthermore, the distance in the short direction between the third discharge holes 8-3 and the discharge holes 8 in the third array 9A-3 adjacent in the second direction of the third discharge holes 8-3 can be shortened.

If n is an even number, it is preferable to set the number of ejection holes 8 belonging to the second array 9A-2 to 2. By doing so, the angle formed between the first array 9A-1 and the second direction can be increased. Furthermore, if the number of discharge holes 8 belonging to the first array 9A-1 and the number of discharge holes 8 belonging to the third array 9A-3 are made the same, the discharge hole array 9A can be arranged close to a straight line. The cross-sectional areas of the first common flow path 20 and the second common flow path 24 can be made large and close to a straight line.

Furthermore, when n is an odd number, it is preferable to set the number of ejection holes 8 belonging to the second array 9A-2 to 1. By doing so, the angle formed between the first array 9A-1 and the second direction can be increased. Furthermore, if the number of discharge holes 8 belonging to the first array 9A-1 and the number of discharge holes 8 belonging to the third array 9A-3 are made the same, the discharge hole array 9A can be arranged close to a straight line. The cross-sectional areas of the first common flow path 20 and the second common flow path 24 can be made large and close to a straight line.

7 (a), 7 (b), 8 (a) and 8 (b) are discharge hole arrangements in another embodiment of the present invention. Parts that have little difference from the embodiment shown in FIG.

FIG. 7A shows an embodiment in which the number of discharge holes 8 belonging to the second array 9A-2 is one when there are 16 discharge hole rows 9B.

FIG. 7B shows an embodiment in which the number of discharge holes 8 belonging to the second array 9A-2 is four when there are 16 discharge hole rows 9B.

FIG. 8 (a) shows that when there are 16 discharge hole rows 9B, the discharge hole row 9A includes the first discharge holes 8-1 and the discharge holes 8 belonging to the 16th discharge hole row. In this embodiment, the first discharge hole 8-1 is connected to the discharge hole 8 that is the fifth closest. In this embodiment, among the discharge holes 8 belonging to the 16th line, the discharge hole 8 having the third shortest distance from the first discharge hole 8-1 is the second discharge hole 8-2, and is fifth. The short discharge hole 8 is the fourth discharge hole 8-4. Further, the first discharge hole 8-1, the third discharge hole 8-3, the second discharge hole 8-2, and the fourth discharge hole 8-4 are arranged in this order in the second direction. The discharge holes 8 located between the first discharge holes 8-1 and the third discharge holes 8-3 are composed of the first array 9A-1 and the third discharge holes 8-3 to the second discharge holes 8. The discharge holes 8 positioned between the second discharge hole 8 and the second discharge hole 8-4 are positioned between the second array 9A-2 and the second discharge hole 8-2. The third array consists of:

In the above description, this is a value in the range of 2 × n + 2 to 3 × n−1 as the value of m. In this range, when the value of m approaches 3 × n, a line connecting the first discharge holes 8-1 and the discharge holes 8 on the first discharge holes 8-1 side of the first array 9A-1; The angle difference between the first array 9A-1 and the line connecting the fourth discharge hole 8-4 and the discharge hole 8 at the end of the third array 9A-3 on the fourth discharge hole 8-4 side is increased. Since the difference in angle between the third array 9A-3 and the third array 9A-3 increases, the cross-sectional areas of the first common channel 20 and the second common channel 24 are not constant. Further, if the cross-sectional areas of the first common flow path 20 and the second common flow path 24 are to be made substantially constant, the cross-sectional area must be reduced to the smallest cross section, resulting in a small cross-sectional area.

In order to reduce such influence, 2 × n + 2 to 2.5 × n is appropriate as the value of m. In order to set the value of m within this range, the discharge hole array 9A includes the first discharge hole 8-1 and the fifth discharge hole 8-1 among the discharge holes 8 belonging to the nth row. What is necessary is just to arrange | position so that the discharge hole 8 close | similar to may be connected. If it arrange | positions in that way, it will become arrangement | positioning of the above-mentioned discharge hole 8.

FIG. 8B shows an embodiment in which the number of discharge holes 8 belonging to the second array 9A-2 is one when there are 15 discharge hole rows 9B.

Subsequently, the arrangement range of the discharge holes 8 when the discharge hole array 9A is arranged linearly will be described. FIG. 9 shows the first to fourth discharge holes 8-1 to 8-4. A straight line connecting the first discharge hole 8-1 and the fourth discharge hole 8-4 is a virtual straight line 9AA. If the position in the row direction is represented by x and the position in the column direction is represented by y, the virtual straight line 9AA is represented by y = (((15 ÷ 29) × (x−1)) mod 16) +1. However, mod represents the calculation of the remainder, 15 is the difference in the column direction between the first discharge hole 8-1 and the fourth discharge hole 8-4, and 29 is the first discharge hole 8-1 and the fourth discharge hole. This is the difference in the row direction from the discharge hole 8-4.

In each row, the position closest to the virtual straight line 9AA among the positions where the discharge holes 8 can be arranged is a range A1 hatched with a diagonal line. The discharge holes 8 are most preferably arranged in this range A1. In FIG. 9, a range A2 hatched by a horizontal line is within a range of ± 2 rows with respect to the range A1. The discharge holes 8 may be arranged in the range A2. Here, the reason why it is within ± 2 rows, that is, within the width of 4 rows is to make it within 1/4 of 16 rows of the total number of rows. Even when the total number of rows is other than 16, it is preferable to arrange in the region A2, which is a region within 1/4 of the total number of rows. However, when the number of rows is 7 or less, the region A2 is within ± 1 rows of the region A1. This is because even in the case of seven rows or less, the region A2 becomes the same as the region A1 and is difficult to arrange if it is within ¼ of the total number of rows. Further, when the distance between the rows is not the same, it may be within ¼ of the distance between the farthest rows.

DESCRIPTION OF SYMBOLS 1 ... Color inkjet printer 2 ... Liquid discharge head 2a ... Head main body 4 ... (1st) Channel member 4a-g
4-1 ... Pressure chamber surface 4-2 ... Discharge hole surface 6 ... Second

flow path member

6a, 6b ... (second flow path member) plate 6ba, 6bb ... Partition 6c ... (through hole of second flow path member) 6c-2 ... Widened portion of through hole 8 ... Discharge hole 8-1 ... First discharge hole 8-2 ... Second discharge Hole 8-3 ... third discharge hole 8-4 ... fourth discharge hole 9A ... discharge hole array 9A-1 ... first array 9A-2 ... second array 9A-3 .. 3rd array 9B ... discharge hole row 10 ... pressurizing chamber 10a ... pressurizing chamber body 10b ... partial flow path (decender)
11A ... pressurization chamber row 11B ... pressurization chamber row 12 ... first individual flow path (individual supply flow path)
14 ... Second individual flow path (individual discharge flow path)
20 ... 1st common flow path (common supply flow path)
20a ... (first common flow path) opening 22 ... first integrated flow path (integrated supply flow path)
22a ... 1st integrated flow path main body 22b ... 1st connection flow path (supply connection flow path)
22c, 22d ... (first integrated flow path) opening 24 ... second common flow path (common discharge flow path)
24a ... (second common flow path) opening 26 ... second integrated flow path (integrated discharge flow path)
26a, second integrated flow channel body 26b, second

connection flow channel

26c, 26d, opening (of second integrated flow channel) 40, piezoelectric actuator substrate 40a, piezoelectric ceramic layer 40b, ..Piezoelectric ceramic layer (diaphragm)
42 ... Common electrode 44 ... Individual electrode 44a ... Individual electrode body 44b ... Extraction electrode 46 ... Connection electrode 50 ... Displacement element (pressure part)
DESCRIPTION OF SYMBOLS 70 ... Head mounting frame 72 ... Head group 80A ... Paper feed roller 80B ... Collection roller 82A ... Guide roller 82B ... Conveyance roller 88 ... Control part P ... Printing paper

Claims

A liquid discharge head having a plurality of discharge holes for discharging liquid,
When the liquid discharge head is viewed in plan view,
The plurality of ejection holes are arranged on n (n is an integer greater than or equal to 5) rows substantially parallel to each other, and the n rows are in a direction intersecting the n rows. In the direction, the first row, the second row,... The nth row are arranged in this order.
The one discharge hole belonging to the first row is defined as a first discharge hole, and the discharge hole having the second shortest distance from the first discharge hole among the discharge holes belonging to the n-th row. The second discharge hole, the fourth shortest discharge hole is the fourth discharge hole,
A direction from the second discharge hole toward the fourth discharge hole is a second direction,
Among the discharge holes belonging to the first row and positioned in the second direction with respect to the first discharge hole, the discharge hole having the shortest distance from the first discharge hole is When setting the third discharge hole,
The first to fourth discharge holes are arranged in the order of the first discharge hole, the second discharge hole, the third discharge hole, and the fourth discharge hole in the second direction.
The discharge holes belonging to the 2nd to (n-1) th rows are arranged in a linear discharge hole row from the first discharge holes to the fourth discharge holes,
The discharge hole row includes one discharge hole belonging to each of the 2nd to (n-1) th rows, and the discharge hole row extends from the first discharge hole to the first in the second direction. A first array of the discharge holes arranged between two discharge holes, a second array of the discharge holes arranged from the second discharge holes to the third discharge holes, and the A liquid discharge head comprising a third arrangement of the discharge holes arranged between the third discharge holes and the fourth discharge holes.
A liquid discharge head having a plurality of discharge holes for discharging liquid,
When the liquid discharge head is viewed in plan view,
The plurality of ejection holes are arranged on n (n is an integer greater than or equal to 5) rows substantially parallel to each other, and the n rows are in a direction intersecting the n rows. In the direction, the first row, the second row,... The nth row are arranged in this order.
The one discharge hole belonging to the first row is defined as a first discharge hole, and the discharge hole having the third shortest distance from the first discharge hole among the discharge holes belonging to the n-th row. The second discharge hole, the fifth shortest discharge hole as the fourth discharge hole,
A direction from the second discharge hole toward the fourth discharge hole is a second direction,
Among the discharge holes belonging to the first row and positioned in the second direction with respect to the first discharge hole, the discharge hole having the shortest distance from the first discharge hole is When setting the third discharge hole,
The first to fourth discharge holes are arranged in the order of the first discharge hole, the third discharge hole, the second discharge hole, and the fourth discharge hole in the second direction.
The discharge holes belonging to the 2nd to (n-1) th rows are arranged in a linear discharge hole row from the first discharge holes to the fourth discharge holes,
The discharge hole row includes one discharge hole belonging to each of the 2nd to (n-1) th rows, and the discharge hole row extends from the first discharge hole to the first in the second direction. A first array of the discharge holes disposed between up to three discharge holes, a second array of the discharge holes disposed between the third discharge holes and the second discharge hole, and the A liquid discharge head comprising a third array of the discharge holes disposed between the second discharge holes and the fourth discharge holes.
The entire third array is positioned in the first direction with respect to the second array, and the entire second array is positioned in the first direction with respect to the first array. The liquid discharge head according to 1 or 2.
When n is an even number, the number of the discharge holes belonging to the second array is 2, and when n is an odd number, the number of the discharge holes belonging to the second array is 1.
4. The liquid discharge head according to claim 1, wherein the number of the discharge holes belonging to the first array is equal to the number of the discharge holes belonging to the third array.
A plurality of pressurizing chambers, a plurality of first common flow paths, and a plurality of pressurizing units that pressurize each of the plurality of pressurizing chambers;
The plurality of discharge holes are respectively connected to the plurality of pressurizing chambers,
When the liquid discharge head is viewed in plan view,
The plurality of first common flow paths extend along the discharge hole row,
The plurality of pressurizing chambers are arranged on the plurality of pressurizing chamber rows in which the pressurizing chambers are arranged along the discharge hole row, and are aligned with the pressurizing chamber row to which the pressurizing chamber belongs. 5. The liquid discharge head according to claim 1, wherein the liquid discharge head is connected to the first common flow path arranged in the above.
A plurality of second common flow paths extending along the first direction;
When the liquid discharge head is viewed in plan view,
The second common flow path belongs to the pressurization chamber row arranged side by side with the second common flow path, and the pressurization chamber connected to the first common flow path, or the first common flow path The liquid discharge head according to claim 6, wherein the liquid discharge head is connected to a partial flow path connecting the pressure chamber connected to the flow path and the discharge hole.
7. A recording apparatus comprising: the liquid discharge head according to claim 1; a transport unit that transports a recording medium to the liquid discharge head; and a control unit that controls the liquid discharge head.