JP2015150881A - Liquid discharge head and recording device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge head in which flow passages can be arranged with high area efficiency and a recording device using the same.SOLUTION: A liquid discharge head comprises: a plate-like passage member 4 that has a plurality of discharge holes 8, a plurality of pressure chambers 10, a plurality of first common supply passages 20 and a plurality of first common collecting passages 24; and a plurality of pressure portions 50. The plurality of first common supply passages 20 and the plurality of first common collecting passages 24 are extended along a first direction, and arranged alternately in a second direction, which is a direction crossing the first direction. On both sides of the first common supply passages 20 and the first common collecting passages 24 are arrayed a plurality of pressure chambers 10. The plurality of pressure chambers 10 are respectively connected to any of the plurality of first common supply passages 22 through a plurality of first passages 12 and respectively connected to any of the plurality of first common collecting passages 24 through a plurality of second passages 14.

Description

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

  Conventionally, as a print head, for example, an ink jet 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. It is known that the liquid is circulated including the gas (see, for example, Patent Document 1). In the liquid discharge head of the cited document 1, the liquid that has entered the pressure chamber from the common flow path returns to the same common flow path.

JP 2008-200902 A

  In the liquid discharge head as described in Patent Document 1, the liquid passing through the pressurizing chamber is supplied from the common flow path and returns to the same common flow path, so that the amount of liquid passing through the pressurizing chamber is difficult to control. There was a problem. On the other hand, if the common flow path for supplying the liquid to the pressurization chamber and the common flow path for discharging the liquid from the pressurization chamber are different flow paths, the number of common flow paths increases. There was a problem that it was difficult to arrange the passage and the pressurizing chamber.

  Accordingly, an object of the present invention is to provide a liquid discharge head capable of arranging flow paths with an area efficiency and a recording apparatus using the same.

  The liquid discharge head of the present invention has a plurality of discharge holes, a plurality of pressurizing chambers connected to the plurality of discharge holes, a plurality of first common supply channels, and a plurality of first common recovery channels. And a plurality of pressurizing units that pressurize the liquid in the plurality of pressurizing chambers, respectively, and when the channel member is viewed in plan view, The plurality of first common supply channels and the plurality of first common recovery channels extend along a first direction and are alternately arranged in a second direction that intersects the first direction. A plurality of pressurizing chambers are arranged along the first common supply channel on both sides of the first common supply channel, the first common supply channel, and the first common supply channel. The plurality of pressurizing chambers arranged along the common supply flow path are each a plurality of first flow paths. A plurality of pressurizing chambers are arranged along the first common recovery channel on both sides of the one first common recovery channel, and the first common recovery channel, The plurality of pressurizing chambers arranged along the first common recovery channel are connected to each other via a plurality of second channels, and the plurality of pressurizing chambers are respectively connected to the plurality of first chambers. And connected to any one of the plurality of first common supply flow paths via the flow path, and each of the plurality of first common recovery flow paths via the plurality of second flow paths. It is connected to either.

The recording apparatus of the 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.

  According to the liquid ejection head of the present invention, the first common supply channel and the second common supply channel are connected to the pressurizing chambers on both sides of the channel, respectively. The number of common supply channels and second common supply channels can be reduced.

(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 VV line of FIG. 4, (b) is a partial longitudinal cross-sectional view of the head main body of FIG. 2 (a).

  FIG. 1A is a schematic side view of a (color inkjet) printer 1 which is a recording apparatus including a liquid discharge head 2 according to an embodiment of the present invention, and FIG. 1B is a schematic plan view. It is. The printer 1 moves the printing paper P relative to the liquid ejection head 2 by transporting the printing paper P that is a recording medium from the transporting roller 80 a to the transporting roller 80 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 the present 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.

  A flat plate (head mounting) frame 70 is fixed to the printer 1 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. Each 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. Liquid (ink) is supplied to each liquid discharge head 2 from a liquid tank (not shown). One head group 7
The liquid discharge heads 2 belonging to 2 are supplied with the same color of ink, and the four head groups can print four colors of ink. 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 ejection 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 ejection head 2 is printed. The number of the liquid ejection heads 2 included in the head group 72 and the number of the head groups 72 can be appropriately changed according to the printing target and printing conditions. For example, the number of head groups 72 may be increased to perform multicolor printing. Also, by arranging a plurality of head groups 72 that print in the same color and printing alternately in the transport direction, the printing speed (transport speed) 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.

  Further, 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 a 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 conveyed at a constant speed by rotating the conveyance roller 82 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.

  In addition to the printing paper P, the recording medium may be a cloth or the like. In addition, the printer 1 is configured to convey a conveyance belt instead of the printing paper P, and the recording medium is not only a roll-shaped one, but also a sheet, cut cloth, wood, It may be a tile. 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. In particular, if the discharge characteristics (discharge amount, discharge speed, etc.) of the liquid discharged from the liquid discharge head 2 are affected by the outside, the temperature of the liquid discharge head 2, the temperature of the liquid in the liquid tank, the liquid tank Depending on the pressure applied by the liquid to the liquid ejection head 2, the drive signal for ejecting the liquid in the liquid ejection head 2 may be changed.

  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. 4, and FIG. 5B shows the first main body 2 in the vicinity of the opening 20 a of the first common supply channel 20. 4 is a partial longitudinal sectional view taken along a common supply channel 20. FIG. 2 to 4, in order to make the drawings easy to understand, a flow path or the like that should be drawn with a broken line below other objects is drawn with a solid line. In FIG. 2A, the flow path in the first flow path member 4 is almost omitted, and only the arrangement of the pressurizing chamber 10 is shown.

  In addition to the head main body 2a, the liquid discharge head 2 may include a metal casing, a driver IC, a wiring board, and the like. 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.

  The first flow path member 4 constituting the head body 2a has a flat plate shape, and the thickness thereof is about 0.5 to 2 mm. A number of pressurizing chambers 10 are arranged in the plane direction on the pressurizing chamber surface 4-1, which is the first main surface of the first flow path member 4. On the discharge hole surface 4-2 that is the second main surface of the first flow path member 4, a large number of discharge holes 8 through which liquid is discharged are arranged in the plane direction. The discharge hole 8 is connected to the pressurizing chamber 10.

  The first channel member 4 includes a plurality of first common supply channels (hereinafter sometimes referred to as first supply channels) 20 and a plurality of first common recovery channels (hereinafter referred to as first recovery channels). 24 are arranged to extend along the first direction. The first supply channel 20 and the first recovery channel 24 are alternately arranged in the second direction, which is a direction intersecting the first direction.

  The pressurizing chambers 10 are arranged along both sides of the first supply flow path 20, and constitute a total of two pressurizing chamber rows 11 </ b> A, one on each side. The first supply channel 20 and the pressurizing chambers 10 arranged on both sides of the first supply channel 20 are connected via a first channel 12 that is an individual supply channel.

  The pressurizing chambers 10 are arranged along both sides of the first recovery flow path 24, and constitute a total of two pressurizing chamber rows 11 </ b> A, one on each side. The first recovery flow path 22 and the pressurizing chambers 10 arranged on both sides thereof are connected via a second flow path 14 that is an individual recovery flow path.

  With the configuration described above, in the first flow path member 4, the liquid supplied to the first supply flow path 20 flows into the pressurizing chambers 10 arranged along the first supply flow path 20, and a part thereof The other liquid is discharged from the discharge hole 8, and another part of the liquid flows into the first recovery flow path 24 located on the opposite side of the first supply 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 first recovery channel 24 on both sides of the first supply channel 20 and the first supply channel 20 on both sides of the first recovery channel 24, one pressurizing chamber row 11A is provided. One first supply flow path 20 and one first recovery flow path 24 are connected, and another first supply flow path 20 and another first recovery flow path with respect to another pressurization chamber row 11A. Compared with the case where 24 is connected, since the number of the 1st supply flow paths 20 and the 1st collection | recovery flow paths 24 can be about a half, it is preferable. Since the number of first supply channels 20 and first recovery channels 24 is small, the number of pressurizing chambers 10 is increased to increase the resolution, or the first supply channel 20 and the first recovery channel 24 are made thicker. 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 flow path 12 on the first supply flow path 20 side connected to the first supply flow path 20 is affected by the pressure loss, and the pressure of the first flow path 12 in the first supply flow path 20 is reduced. It depends on the position. The pressure applied to the portion on the second flow path 14 side connected to the first recovery flow path 24 varies depending on the position of the second flow path 14 in the first recovery flow path 24 due to the effect of pressure loss. If the opening 20a to the outside of the first supply channel 20 is arranged at one end in the first direction and the opening 24a to the outside of the first recovery channel 24 is arranged at the other end in the first direction. The pressure difference due to the arrangement of the first flow paths 12 and the second 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 supply channel 20 and the opening 24a of the first recovery channel 24 open to the pressurizing chamber surface 4-1.

  In the state of not discharging, a liquid meniscus is held in the discharge hole 8. Since the pressure of the liquid in the discharge hole 8 is a negative pressure (a state where the liquid is about to be drawn into the first flow path member 4), the meniscus can be held in balance with the surface tension of the liquid. 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 supply flow path 20 to the first recovery flow path 24.

  The pressurizing chamber 10 is arranged to face the pressurizing chamber surface 4-1, and the pressurizing chamber main body 10a that receives the pressure from the displacement element 50 and the discharge hole surface 4- from below the pressurizing chamber main body 10a. 2 is a hollow region including a partial flow path (descender) 10b 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 its planar shape is a circular shape. Moreover, the descender 10b is arrange | positioned in the position stored in the pressurization chamber main body 10a, when it sees from the pressurization 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 planar shape of the descender 10b is smaller than that of the pressurizing chamber main body 10a, the widths of the first supply channel 20 and the first recovery 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 1, 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. ing.

  In the present embodiment, there are 50 first supply channels 20 and 51 second supply channels 24, and there are 100 pressurizing chamber rows 11A and discharge hole rows 9A. 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 that the pressurizing chambers 10 are shifted in the first direction and arranged in a staggered 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 (the longitudinal direction of the head body 2a) 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 the amount of deviation 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. Eight half (eight) discharge holes. In each discharge hole row 9B, the discharge holes 8 are arranged at intervals of 22.5 dpi.

  If the discharge holes 8 belonging to one discharge hole row 9A are arranged in a straight line along the first direction, printing can be performed so as to fill the predetermined range as described above. However, in such an arrangement, a shift between the second direction and the transport direction that occurs when the liquid discharge head 2 is installed in the printer 1 has a great influence on the printing accuracy. For this reason, it is preferable that the discharge holes 8 are replaced and arranged between the adjacent discharge hole rows 9A from the arrangement of the discharge holes 8 on the straight line described above. In the present embodiment, the discharge holes 8 are replaced in groups of four. Therefore, in one discharge hole row 9A, four discharge holes 8 are arranged in a straight line from one end side in the first direction, and the following eight discharge holes 8 are arranged side by side. The four subsequent discharge holes 8 are arranged on another straight line that is different from the straight line on which the previous eight discharge holes 8 are arranged.

  The first supply channel 20 and the first recovery channel 24 are straight in a range where the discharge holes 8 are arranged in a straight line, and are shifted in parallel between the discharge holes 8 where the straight lines are shifted. Since there are few such deviations in the first supply channel 20 and the first recovery channel 24, the channel 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 supply channel 20 or the first recovery channel 24 is provided on the end side in the second direction with respect to the dummy pressurizing chamber. If the first recovery flow path 24 is disposed on the center side in the second direction with respect to the dummy pressurizing chamber, the disposed flow path becomes the first supply flow path 20, and the dummy pressurization chamber On the other hand, if the first supply channel 20 is disposed on the center side in the second direction, the first recovery channel 24 is formed. Similarly to the normal pressurizing chamber 10, the dummy pressurizing chamber is connected to the first supply channel 20 via the first channel, and is connected to the first recovery channel 24 via the second channel. Yes.

  The common flow path (either the first common supply flow path 20 or the first common recovery flow path 24) located at the end in the second direction has one row of pressurizing chambers 11A to be supplied or recovered. For this reason, the discharge characteristics of the discharge from the pressurization chambers 10 belonging to the one pressurization chamber array 11 </ b> A may 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 basic shape of the dummy pressurizing chamber is the same as that of the normal pressurizing chamber 10, and the discharge hole 8 may or may not be disposed on the discharge hole surface 4-2 side.

  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 supply flow path 20 for supplying the liquid to the pressure chamber 10 to which it belongs supplies the liquid to the two pressure chamber rows 11A in the same manner as the other normal first supply flow paths 20, and the second As with other normal first recovery channels 24, the first recovery channels 24 that recover the liquid in the pressurization chambers 10 belonging to the pressurization chamber column 11A located at the second position from both ends of the direction are added in two rows. Since the liquid in the pressure chamber row 11A is collected, a difference in ejection characteristics is less likely to occur.

  Among 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 do not have an interval in the second direction of 360 dpi. Therefore, 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 a second common supply flow path (hereinafter referred to as a second flow path) that supplies liquid to the first supply flow path. And a second common recovery channel (hereinafter also referred to as a second recovery channel) 26 for recovering the liquid in the first recovery channel. . The second flow path member 6 is thicker than the first flow path member 4 and has a thickness of 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 40 board | substrate 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.

  Moreover, the through-hole 6c penetrates the 2nd flow path member up and down. The through hole 6c is passed through a wiring member such as an 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 6c-2 which is wide in the short direction, and the wiring member extending from the piezoelectric actuator substrate 40 to both sides in the short direction is widened. It is bent by the part 6c-2 and goes upward, and passes through the through hole 6. In addition, since the convex part of the part extended to the wide part 6c-2 may damage a wiring member, it is preferable to make it R shape.

  By disposing the second supply channel 22 in the second channel member 6 that is different from the first channel member 4 and is thicker than the first channel member 4, the cross-sectional area of the second supply channel 22 is increased. Thus, the difference in pressure loss due to the difference in position where the second supply channel 22 and the first supply channel 20 are connected can be reduced. The flow resistance of the second supply flow path 22 (more precisely, the flow resistance of the second supply flow path 22 in a range connected to the first supply flow path 20) is equal to that of the first supply flow path 20. It is preferable to make it 1/100 or less.

  By disposing the second recovery flow path 26 in a second flow path member 6 that is different from the first flow path member 4 and thicker than the first flow path member 4, the cross-sectional area of the second recovery flow path 26 is increased. Thus, the difference in pressure loss due to the difference in the position where the second recovery channel 26 and the first recovery channel 24 are connected can be reduced. The flow path resistance of the second recovery flow path 26 (more precisely, the flow resistance of the second recovery flow path 26 that is connected to the first recovery flow path 22) is equal to that of the first recovery flow path 24. It is preferable to make it 1/100 or less.

  The second supply channel 22 is arranged at one end of the second channel member 6 in the short direction, the second recovery channel 26 is arranged at the other end of the second channel member 6 in the short direction, Each flow path is directed to the first flow path member 4 side so as to be connected to the first supply flow path 20 and the first recovery flow path 24, respectively. By doing so, the cross-sectional areas of the second supply flow path 22 and the second recovery flow path 26 can be increased (that is, the flow path resistance can be reduced), and the first flow path member 4 can be formed by the second flow path member 6. The outer periphery of the wiring member can be fixed to increase the rigidity, and a through hole 6c through which the wiring member 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 second supply channel body 22a, which is a portion of the second supply channel 22 extending in the second direction and having a low channel resistance, and a second recovery channel 26 A groove serving as a second supply flow path body 26a, which is a portion having a low flow resistance extending in the second direction, is disposed.

A plurality of supply connection channels 22b extend downward (in the direction of the first channel member 4) from the groove serving as the second supply channel main body 22a, and are opened on the pressurizing chamber surface 4-1. It is connected to the opening 20a of the first supply channel. Each supply connection flow path 22b is partitioned by a partition 6ba (that is, the first supply flow path 20 side of the supply connection flow path 22b is branched). Thereby, the rigidity of the connection between the second flow path member 6 and the first flow path member can be increased. Furthermore, in the second direction, the length of the partition 6ba is longer than the length of the supply connection channel 22b, so that the rigidity of the connection between the second channel member 6 and the first channel member can be further increased. .

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

  The plate 6 a is provided with openings 22 c and 22 d at both ends in the second direction of the second supply flow path 22. The plate 6 a is provided with openings 26 c and 26 d at both ends in the second direction of the second recovery flow path 26. When supplying the 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 second supply 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 recovery flow channel 26 may be discharged from one opening (for example, the opening 26c) and from the other opening (for example, the opening 26d).

  When printing, there are several ways to supply and recover the liquid. One is that all of the liquid supplied to the second supply channel 22 enters the first channel member 4 and further enters the second recovery channel 26 and is discharged to the outside. At this time, no liquid is supplied to the second recovery flow path 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 pressure difference due to the pressure loss, it is preferable to supply from two openings and collect from the two openings, but the connection of the tube for supplying and discharging the liquid makes the pressure control 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 second supply flow path 22, collect the liquid from the other opening (for example, 22d), and 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 second supply flow path 22 becomes higher than the pressure of the second recovery 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 two methods may be combined to supply / discharge the second supply flow path 22 and only recover from the second recovery flow path 26. Conversely, only the second supply channel 22 may be supplied and the second recovery channel 26 may be supplied and discharged.

  A damper may be provided in the second supply channel 22 and the second recovery channel 26 so that the supply or discharge of the liquid is stable with respect to fluctuations in the discharge amount of the liquid. Further, by providing a filter in the second supply flow path 22 and the second recovery 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 upper surface of the first flow path member 4, and each displacement element 50 is disposed so as to be positioned on the pressurizing chamber 10. 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 joining 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 has 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 so as to extend from one long side end of the piezoelectric actuator substrate to the other long side end, and the wiring disposed in the signal transmission unit extends along the short direction. If it is arranged in the longitudinal direction, the distance between the wirings can be easily increased.

  Individual electrodes 44 are arranged at positions facing the pressurizing chambers 10 on the upper surface of the piezoelectric actuator substrate 40. 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. In addition, a common electrode surface electrode (not shown) electrically connected to the common electrode 42 via a via hole is formed on the upper surface of the piezoelectric actuator substrate 40. The common electrode surface electrode and the common electrode 42 are electrically connected through a conductor in a via hole (not shown) disposed on the piezoelectric ceramic layer 21b.

  The first flow path member 4 included in the head main body 2a is configured by laminating a flow path member main body 4a and a nozzle plate 4b. A discharge hole 8 is opened in the nozzle plate 4b.

  A pressurization chamber body 10a is formed on the first main surface 4a-1 (the same surface as the pressurization chamber surface 4-1) of the flat channel member body 4a, and the piezoelectric actuator substrate 40 is joined thereto. . The nozzle plate 4b is joined to the second main surface 4a-2 opposite to the first main surface 4-1 of the flow path member main body 4a.

  A first through hole 10, a second through hole 12, a first groove 22, a second groove 24, and a third groove 14 are formed in the flow path member main body 4a.

  The through-hole 10 becomes the pressurizing chamber 10 and penetrates from the first main surface 4a-1 to the second main surface 4a-2 and is directed from the second main surface 4a-2 to the first main surface. Thus, the cross-sectional shape is increased. The 1st groove | channel 20 becomes the 1st supply flow path 20, and is opened to the 2nd main surface 4a-2. The 2nd groove | channel 24 becomes the 1st collection | recovery flow path 24, and is opened to 2nd main surface 4a-2.

  When the flow path member main body 4a is viewed in plan, there are a plurality of overlapping portions 4aa (shaded portions in FIG. 3) in which the first through hole 10 and the first groove overlap each other. The overlapping portion 4aa includes a second through hole (first flow path) 12 that penetrates from the first main surface 4a-1 side to the second main surface 4a-2 side.

  A third groove 14 having a depth smaller than that of the second groove 24, which connects the first through hole 10 and the second groove 24, is disposed on the second main surface 4 a-2. The third groove 14 becomes a second flow path 14 that connects the pressurizing chamber 10 and the first recovery flow path 24 by being blocked by the nozzle plate 4 b that is the second plate.

The above through-holes and grooves are all shaped so that the cross-sectional shape is constant toward the first main surface 4a-1, or the cross-sectional shape becomes larger toward the first main surface 4a-1. Either the shape of the cross section is constant toward the second main surface 4a-2, or the shape of the cross section is increasing toward the second main surface 4a-2. Since it has such a structure, the flow path member main body 4a can be integrally formed by a mold that can be divided vertically. Moreover, even when it is formed by grinding or the like, it is easy to process because it has a shape that can be easily processed from the first main surface 4a-1 or the second main surface 4a-2.

  The thickness of the first flow path member main body 4a is about 500 μm to 2 mm. A nozzle plate 4b having a thickness of about 10 to 100 μm, which is a second plate, is joined to the second main surface 4a-2 side of the first flow path member main body 4a. A piezoelectric actuator substrate 40, which is a first plate, is bonded to the first main surface 4a-1 side of the first flow path member main body 4a. In this way, it is possible to configure a liquid discharge head that can discharge liquid by supplying liquid from the opening 20a and collecting liquid from the opening 24a. As described above, the second flow path member 6 may be further laminated on the liquid discharge head.

  The first flow path member main body 4a may be configured by laminating a plurality of plates made of metal or the like. In that case, each flow path is configured by combining holes and grooves processed by etching or the like. For example, the first flow path member main body 4a may be configured by stacking the following six plates. The first plate from the top (pressurizing chamber surface 4a-1) has a hole serving as the pressurizing chamber body 10a. The second plate has a hole serving as a part of the descender 10b and a hole serving as a first flow path. The third to fifth plates each have a hole that becomes a part of the descender 10b, a hole that becomes a part of the first supply flow path 20, and a hole that becomes a part of the first recovery flow path 24. Yes. The 3rd to 5th plates have holes of the same shape in design and may be composed of a single plate, but since the depth of the holes is deep, the accuracy of the cross-sectional shape of etching deteriorates, It consists of three plates. The sixth plate has a hole that becomes the second flow path 14, a hole that becomes a part of the first supply flow path 20, and a hole that becomes a part of the first recovery flow path 24.

  To summarize the liquid flow, the liquid supplied to the second supply flow path 22 passes through the first supply flow path 20 and the first flow path 12 in order. A part of the liquid enters the pressurizing chamber 10 and is discharged from the discharge hole 8. The liquid that has not been discharged passes through the second flow path 14, enters the first recovery flow path 24, enters the second recovery flow path, and is discharged outside the head body 2.

The piezoelectric actuator substrate 40 has a laminated structure including two piezoelectric ceramic layers 21a and 21b which are piezoelectric bodies. Each of these piezoelectric ceramic layers 21a and 21b has a thickness of about 20 μm. The thickness from the lower surface of the piezoelectric ceramic layer 21a of the piezoelectric actuator substrate 40 to the upper surface of the piezoelectric ceramic layer 21b is about 40 μm. Both of the piezoelectric ceramic layers 21 a and 21 b extend so as to straddle the plurality of pressure chambers 10. The piezoelectric ceramic layers 21a, 21b 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 ceramic layer 21b functions as a vibration plate and does not necessarily need to be a piezoelectric body. Instead, another ceramic layer or metal plate that is not a piezoelectric body may be used.

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 individual electrode 44 includes the individual electrode main body 44a disposed at a position facing the pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 40 as described above, and the extraction electrode 44b extracted therefrom. A connection electrode 26 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 26 is made of, for example, silver-palladium containing glass frit, and has a convex shape with a thickness of about 15 μm. Further, the connection electrode 26 is electrically joined to an electrode provided in the signal transmission unit 60. Although details will be described later, the individual electrode 44 includes:
A drive signal is supplied 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 21a and the piezoelectric ceramic layer 21b. That is, the common electrode 42 extends so as to cover all the pressurizing chambers 10 in the region facing the actuator substrate 21. The thickness of the common electrode 42 is about 2 μm. The common electrode 42 is connected to the common electrode surface electrode formed on the piezoelectric ceramic layer 21a so as to avoid the electrode group composed of the individual electrodes 44 through a via hole formed through the piezoelectric ceramic layer 21a. Are grounded and held at the ground potential. The common electrode surface electrode is directly or indirectly connected to the control unit 88 in the same manner as the large number of individual electrodes 44.

  A portion sandwiched between the individual electrode 44 and the common electrode 42 of the piezoelectric ceramic layer 21 a is polarized in the thickness direction, and becomes a displacement element 50 having a unimorph structure 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 21a 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 control unit 88 sets the individual electrode 44 to a predetermined positive or negative potential with respect to the common electrode 42 so that the electric field and the polarization are in the same direction, a portion sandwiched between the electrodes of the piezoelectric ceramic layer 21a. (Active part) contracts in the surface direction. On the other hand, the piezoelectric ceramic layer 21b, which is an inactive layer, is not affected by an electric field, and therefore 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 21a and the piezoelectric ceramic layer 21b, and the piezoelectric ceramic layer 21b is deformed so as to be convex toward the pressurizing chamber 10 (unimorph deformation).

  Next, 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) each time there is a discharge request, and then predetermined. At this timing, the potential is set again. Thereby, the piezoelectric ceramic layers 21a and 21b return to the original (flat) shape at the timing when the individual electrode 44 becomes low potential (beginning), 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.

In other words, a droplet can be ejected by supplying a pulse drive signal that is a low potential for a certain period with the high potential as a reference to the individual electrode 44. If this pulse width is AL (Acoustic Length), which is half the natural vibration period of the liquid in the pressure chamber 10, in principle, the discharge speed and discharge amount of the liquid can be maximized. The natural vibration period of the liquid in the pressure chamber 10 is greatly influenced by the physical properties of the liquid and the shape of the pressure chamber 10, but besides that, from the physical properties of the actuator substrate 21 and the characteristics of the flow path connected to the pressurizing chamber 10. Also affected by.

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.

DESCRIPTION OF SYMBOLS 1 ... Printer 2 ... Liquid discharge head 2a ... Head main body 4 ... (1st) Channel member 4a ... Channel member main body 4aa ... Duplicate part 4a-1, ... Upper surface (of the channel member main body), first main surface 4a-2,... (Lower surface of the channel member main body), second main surface 4b ... Nozzle plate (second plate)
4-1 ... pressurization chamber surface, first main surface 4-2 ... discharge hole surface 6 ... second flow path member 6a, 6b ... (second flow path member) plate 6ba, 6 bb... Partition 6 c... Through hole (of second flow path member) 6 c-2. Widened portion of through hole 8... Discharge hole 9 B. DESCRIPTION OF SYMBOLS 10 ... Pressurization chamber, 1st through-hole 10a ... Pressurization chamber main body 10b ... Partial flow path (decender)
11B: Pressurizing chamber row 11A: Pressurizing chamber row 12: First flow path (individual supply flow path), second through hole 14: Second flow path (individual discharge flow path), 3rd groove 20 ... 1st (common) supply flow path, 1st groove 20a ... (opening of 1st common supply flow path) 22 ... 2nd (common) supply flow path 22a ... 1st 2 Common supply flow path body 22b ... Supply connection flow path 22c, 22d ... Opening of (second common supply flow path) 24 ... First (common) discharge flow path, second groove 24a ... (First common recovery channel) opening 26... Second (common) discharge channel 26 a... Second common recovery channel body 26 b... Recovery connection channel 26 c, 26 d. Opening of common recovery flow path 40 ... Piezoelectric actuator substrate (first plate)
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)
60 ... Signal transmission unit 70 ... (head mounting) frame 72 ... head group 80a ... feed roller 80b ... collection roller 82a ... guide roller 82b ... conveying roller 88 ...・ Control part P ・ ・ ・ Printing paper

Claims (6)

A flat channel member having a plurality of discharge holes, a plurality of pressure chambers connected to the plurality of discharge holes, a plurality of first common supply channels, and a plurality of first common recovery channels And a plurality of pressurizing units that pressurize the liquid in the plurality of pressurizing chambers, respectively,
When the flow path member is viewed in plan view,
The plurality of first common supply channels and the plurality of first common recovery channels extend along a first direction and are alternately arranged in a second direction that is a direction intersecting the first direction. Has been
A plurality of the pressure chambers are arranged along the first common supply channel on both sides of one first common supply channel, and the first common supply channel and the first common supply flow The plurality of pressurizing chambers arranged along the path are connected to each other via a plurality of first flow paths,
A plurality of the pressure chambers are arranged along the first common recovery channel on both sides of one first common recovery channel, and the first common recovery channel and the first common recovery channel A plurality of the pressurizing chambers arranged along the path are respectively connected via a plurality of second flow paths,
The plurality of pressurizing chambers are connected to any one of the plurality of first common supply channels through the plurality of first channels, respectively, and each through the plurality of second channels, A liquid discharge head connected to any one of the plurality of first common recovery flow paths.   The plurality of first common supply channels are open to the outside at one end in the first direction, and the plurality of first common recovery channels are external at the other end in the first direction. The liquid discharge head according to claim 1, wherein the liquid discharge head is open.   The liquid discharge head according to claim 1, wherein the liquid discharge head is long in the second direction.   The liquid is supplied to the plurality of first common supply channels, the second common supply channel extending in the second direction, and the liquid is recovered from the plurality of first common recovery channels, extending in the second direction. The liquid discharge head according to claim 3, further comprising a second common recovery channel. A second common supply channel for supplying liquid to the plurality of first common supply channels, and a second common recovery channel for recovering liquid from the plurality of first common recovery channels,
The flow resistance of the second common supply flow path is 1/100 or less of the flow resistance of the first common supply flow path;
5. The liquid discharge head according to claim 1, wherein a flow path resistance of the second common recovery flow path is 1/100 or less of a flow path resistance of the first common recovery flow path.   A 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. Recording device.

Images