JP2016030367A - Liquid ejection head, and recording device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection head in which damper effect can be improved, and a recording device using the same.SOLUTION: The liquid ejection head comprises: a flow passage member 4 having a plurality of ejection holes 8, a plurality of pressurization chambers 10, a first common flow passage 20, and a second common flow passage 24; and a plurality of pressurizing parts 50. In the pressurization chambers 10, a partial flow passage 10b is included extending from a pressurization chamber surface 4-1 side to an ejection hole surface 4-2 side, and a wall surface position PT of a first common flow passage 20 side on the pressurization chamber surface 4-1 side of the partial flow passage 10b is located more to the first common flow passage 20 side than a wall surface position PB of the first common flow passage 20 side on the ejection hole surface 4-2 side of the partial flow passage 10b, and a width of the ejection hole surface 4-2 side of the first common flow passage 20 is larger than a width of the pressurization chamber surface 4-1 side of the first common flow passage 20, and a damper 28 is disposed in the wall surface of the ejection hole surface 4-2 side of the first common flow passage 20.SELECTED DRAWING: Figure 6

Description

  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 pressure chamber for pressurizing the liquid so that the liquid is discharged from the discharge hole, a first common flow path for supplying the liquid to the pressure chamber, What is provided with the 2nd common flow path which collect | recovers liquids from a pressure chamber is known. The liquid flows from the first common flow path to the second common flow path through the pressurizing chamber even when the discharge is not performed so that the clogging of the flow path is difficult to occur due to the liquid retention. It is known to circulate liquids including the outside (see, for example, Patent Document 1).

JP 2009-143168 A

  In the liquid discharge head as described in Patent Document 1, when pressure is applied to the liquid in the pressurizing chamber in order to discharge the liquid, other pressure is applied via the first common flow path or the second common flow path. The vibration of the liquid is transmitted to the pressure chamber, thereby causing a problem in that the fluid discharge characteristics (discharge amount and discharge speed) of the liquid discharged from other pressurization chambers fluctuate and fluid crosstalk occurs.

  And in order to suppress fluid crosstalk, it is possible to provide a damper in the 1st common channel or the 2nd common channel. However, if the pressurizing chamber, the first common flow path, the second common flow path, and the like are arranged in the limited volume of the liquid ejection head, the widths of the first common flow path and the second common flow path Needs to be narrowed to some extent, and even if a damper is attached to a narrow channel, the effect of the damper is reduced.

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

The liquid discharge head of the present invention includes a plurality of discharge holes, a plurality of pressurizing chambers connected to the plurality of discharge holes, a first common flow path connected to the plurality of pressurizing chambers, and the plurality of pressurizing chambers. A liquid discharge head including a flow path member having a second common flow path connected to a pressure chamber, and a plurality of pressurization units that pressurize the plurality of pressurization chambers, respectively, wherein the plurality of discharge holes Is opened in the discharge hole surface which is one main surface of the flow path member, and the plurality of pressurizing chambers are arranged on the pressure chamber surface side which is the other main surface of the flow path member. A pressurizing chamber main body, and a partial flow path extending from the pressurizing chamber main body toward the discharge hole surface side and connected to the discharge hole, the second common flow path and the pressurizing chamber Is connected to the discharge hole side of the portion where the first common flow path and the pressurizing chamber are connected. And the wall surface on the first common flow path side on the pressure chamber surface side of the partial flow path is closer to the first common flow path than the wall surface on the first common flow path side on the discharge hole surface side of the partial flow path. The width of the first common flow path on the discharge hole surface side is larger than the width of the first common flow path on the pressure chamber surface side, and the first common flow path is located on the road side. A damper having a width wider than a width of the first common flow path on the discharge hole surface side is arranged on a wall surface of the passage on the discharge hole surface side.

  The liquid discharge head of the present invention includes a plurality of discharge holes, a plurality of pressurization chambers connected to the plurality of discharge holes, a first common flow path connected to the plurality of pressurization chambers, and the plurality A liquid discharge head including a flow path member having a second common flow path connected to the pressurizing chamber, and a plurality of pressurizing units that pressurize the plurality of pressurizing chambers, respectively. The discharge hole is opened to a discharge hole surface which is one main surface of the flow path member, and the plurality of pressurizing chambers are arranged on the pressure chamber surface side which is the other main surface of the flow path member. A pressurizing chamber main body, and a partial flow path extending from the pressurizing chamber main body to the discharge hole surface side and connected to the discharge hole. The portion where the pressure chamber is connected is closer to the discharge hole than the portion where the first common flow path and the pressurizing chamber are connected. The wall surface on the second common flow path side on the pressure chamber surface side of the partial flow path is more than the wall surface on the second common flow path side on the discharge hole surface side of the partial flow path. 2, the width of the second common channel on the discharge hole surface side is larger than the width of the second common channel on the pressure chamber surface side, A damper having a width wider than a width of the second common flow path on the discharge hole surface side is disposed on a wall surface of the two common flow paths on the discharge hole surface side.

  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.

  According to the liquid discharge head of the present invention and the recording apparatus using the same, the damper effect is enhanced, so that crosstalk and the like can be reduced and the recording accuracy can be increased.

(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 the fragmentary longitudinal cross-sectional view along the VV line of FIG. 4, (b) is a fragmentary longitudinal cross-sectional view of the head main body of Fig.2 (a). It is a fragmentary longitudinal cross-sectional view along the XX line of FIG. It is a fragmentary longitudinal cross-sectional view of the head main body of other embodiment of this invention. It is a fragmentary longitudinal cross-sectional view of the head main body of other embodiment of this invention. It is a fragmentary longitudinal cross-sectional view of the head main body of other embodiment of this invention.

  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). The liquid ejection heads 2 belonging to one head group 72 are supplied with the same color ink, and four color inks can be printed by the four head groups. 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 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, 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 is a diagram illustrating the first common in the vicinity of the opening 20 a of the first common flow path 20 of the head body 2. 2 is a partial longitudinal sectional view along a flow path 20. FIG. 6 is a longitudinal sectional view taken along line XX in FIG.

  Each figure is drawn as follows for easy understanding of the drawing. 2-4, the flow path etc. which should be drawn with a broken line under other things are drawn with the continuous 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. 3 and 4, the first common flow path 20 indicates the position of the wall surface on the pressurizing chamber surface 4-1 side.

  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. The head main body 2a has a first flow path member 4 as a support member, a second flow path member 6 for supplying a liquid to the first flow path member 4, and a displacement element 50 as a pressure unit. A piezoelectric actuator 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. 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.

  A plurality of first common channels 20 and a plurality of second common channels 24 are arranged in the first channel member 4 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 pressurizing chambers 10 are arranged along both sides of the first common flow path 20, and constitute a total of two pressurizing chamber rows 11 </ b> A, one 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 constitute one total of two pressurizing chamber rows 11A. The first integrated flow path 22 and the pressurizing chambers 10 arranged on both sides of the first integrated flow path 22 are connected via a second individual flow path 14 that is an individual discharge flow path.

  In other words, the pressurizing chambers 10 are arranged side by side on a virtual line, the first common flow path 20 extends along one side of the virtual line, and along the other side of the virtual line. The second common flow path 24 extends. In the head main body 2, the virtual line in which the pressurizing chambers 10 are arranged is a straight line, but may be a curved line or a broken line.

  With the configuration as described above, in the first flow path member 4, the liquid supplied to the second common flow path 24 flows into the pressurizing chambers 10 arranged along the second common flow path 24, and partly The other liquid is discharged from the discharge hole 8, and the other part of the liquid flows into the first common channel 20 located on the opposite side of the second common channel 24 with respect to the pressurizing chamber 10. The fluid is discharged from the 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 a 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 channel 12 on the first common flow channel 20 side connected to the first common flow channel 20 is affected by the pressure loss, and thus the first individual flow channel in the first common flow channel 20. Varies with 12 positions. The pressure applied to the portion on the second individual flow path 14 side connected to the second common flow path 24 varies depending on the position of the second individual flow path 14 in the second common flow path 24 due to the effect of pressure loss. 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.

  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. Therefore, it is necessary to prevent the difference in the pressure of the liquid in the discharge holes 8 from becoming too large when the liquid flows from the second common flow path 24 to the first common flow path 20.

  A wall surface on the discharge hole surface 4-2 side of the first common flow path 20 is a damper 28. One surface of the damper 28 faces the first common flow path 20, and the other surface faces the damper chamber 29. Due to the presence of the damper chamber 29, the damper 28 can be deformed, and the volume of the first common flow path 20 can be changed by the deformation. When the liquid in the pressurizing chamber 10 is pressurized to discharge the liquid, a part of the pressure is transmitted to the first common channel 20 through the liquid. As a result, the liquid in the first common flow path 20 vibrates, and the vibration is transmitted to the original pressurizing chamber 10 and the other pressurizing chambers 10 to cause fluid crosstalk that fluctuates the discharge characteristics of the liquid. May occur. If the damper 28 exists, the vibration of the liquid transmitted to the first common flow path 20 vibrates and further attenuates, so that the vibration of the liquid in the first common flow path 20 becomes difficult to be sustained. The influence of fluid crosstalk can be reduced.

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 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 substantially cylindrical shape whose diameter is smaller than that of the pressurizing chamber body 10a, and has a circular cross-sectional 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 has a small cross-sectional area on the discharge hole surface 4-2 side. Thereby, the width | variety by the side of the discharge hole 4-2 of the 1st common flow path 20 can be enlarged, and the effect of the damper 28 arrange | positioned at the part can be made high. These will be described in detail later.

  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. Yes.

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

  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 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. 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, the influence on the printing accuracy is increased due to the deviation between the second direction and the transport direction that occurs when the liquid ejection head 2 is installed in the printer 1. 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 common flow path 20 and the second common flow path 24 are straight in a 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. Since there are few such shifted locations in the first common flow path 20 and the second common flow path 24, the flow path 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 path (either the first common flow path 20 or the first common discharge flow path 24) located at the end in the second direction has a single pressurization chamber line 11A to be supplied or recovered, For this reason, the liquid discharge characteristics from the pressurization chambers 10 belonging to the one pressurization chamber array 11 </ b> A may vary with respect to the liquid 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 second common flow path 24 for supplying the liquid to the pressurizing chamber 10 to which it belongs is configured to supply the liquid to the two pressurization chamber arrays 11A in the same manner as other normal second common flow paths 24. The first common flow path 20 for recovering the liquid in the pressurization chamber 10 belonging to the pressurization chamber row 11A located second from both ends in the direction is the same as other normal first common flow paths 20 in two rows. Since the liquid in the pressure chamber row 11A is collected, 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 pressure chamber surface 4-1 of the first flow path member 4, and the second common flow path 26 that supplies the liquid to the second common flow path 24 and the first common flow path member 4. And a first integrated flow path 22 for collecting the liquid in the flow path 20. The thickness of the 2nd flow path member 6 is thicker than the 1st flow path member 4, and is about 5-30 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.

Further, a through hole 6 c penetrates up and down at the center of the second flow path member 6. The through hole 6c is
A wiring member such as an FPC (Flexible Printed Circuit) that transmits a drive signal for driving the piezoelectric actuator substrate 40 is passed therethrough. 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 the wiring member extending from the piezoelectric actuator substrate 40 to both sides in the short direction is widened. It is bent at the 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 wiring member, 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 flow resistance of the first integrated flow path 22 (more precisely, the flow resistance of the first integrated flow path 22 that is connected to the first common flow path 20) is It is preferable to make it 1/100 or less.

  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 flow resistance of the second integrated flow path 26 (more precisely, the flow resistance of the second integrated flow path 26 that is connected to the first integrated flow path 22) is that of the second common flow path 24. It is preferable to make it 1/100 or less.

  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. By doing so, the cross-sectional areas of the first integrated flow path 22 and the second integrated 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 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 main body 22a, and open on the pressure 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. Further, in the second direction, the length of the partition 6bb is longer than the length of the second connection 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 6 a has openings 22 c and 22 at both ends in the second direction of the first integrated flow path 22.
d is provided. 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 liquid to the liquid discharge head 2 that does not contain liquid, the liquid is supplied from one opening (for example, the opening 26c) so that the liquid in the second integrated flow path 26 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, 26d), it is possible to prevent the gas from entering the first flow path member 4. Similarly, the first integrated flow path 22 may be supplied from one opening (for example, the opening 22c) and discharged from the other opening (for example, the opening 22d).

  There are several ways to supply and collect liquids when printing. One is that all of the liquid supplied to the second integrated flow path 26 enters the first flow path member 4 and further enters the first integrated flow path 22 and is discharged to the outside. At this time, the liquid from the outside is not supplied to the first integrated flow path 22. In this case, the liquid is supplied from the two openings 26c and 26d and recovered from the two openings 22c and 22d, and the liquid is supplied from one of the openings 26c and 26d, the other is closed, and the opening 22c is closed. , 22d, the liquid is recovered from one of them, and the other is closed. Since which opening is used can be combined, there are a total of four methods. 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 26c and recovered from the opening 22d, or supplied from the opening 26d and recovered from the opening 22c.

  In another method of supplying and discharging, liquid is supplied from one opening (for example, 26c) of the second integrated flow path 26, recovered from the other opening (for example, 26d), and one opening ( For example, liquid is supplied from 22d) and recovered from the other opening (for example, 22c). If the pressure of each supply / discharge is adjusted so that the pressure of the second integrated flow path 26 becomes higher than the pressure of the first integrated flow path 22, 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 among the methods described so far.

  By combining the above-described methods, the second integrated flow path 26 may be supplied and discharged, and only the recovery from the first integrated flow path 22 may be performed. Conversely, only the second integrated flow path 26 may be supplied, and the first integrated flow path 22 may be supplied and discharged.

  Furthermore, the relationship between supply and recovery described above may be reversed. For example, the opening 22d of the first integrated flow path 22 may be closed and liquid may be supplied from the opening 22c, and the opening 22c of the second discharge flow path 26 may be closed and the liquid may be recovered from the opening 26d.

  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 that 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 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 6 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 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 obtained.

  Individual electrodes 44 are 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, an upper cover plate 4b, manifold plates 4c to f, a lower cover plate 4g, a cover space plate 4h, and a nozzle plate 4i in order from the upper surface 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. Among the manifold plates 4c to f, there are plates having the same shape, which may be constituted by one plate, but are constituted by four plates in order to form 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.

  A pressurizing chamber body 10a is opened on the pressurizing chamber surface 4-1 of the flat channel member 4, and the piezoelectric actuator substrate 40 is joined thereto. The pressurizing chamber surface 4-1 has an opening 24 a for supplying a liquid to the second common channel 24 and an opening 20 a for recovering the liquid from the first common channel 20. A discharge hole 8 is opened in the discharge hole surface 4-2 on the opposite side of the pressure chamber surface 4-1 of the flow path member 4. In addition, a plate may be further laminated on the pressurizing chamber surface 4-1, and the opening of the pressurizing chamber main body 10a may be closed, and the piezoelectric actuator substrate 40 may be bonded thereon. By doing so, the reliability can be further improved when the liquid to be ejected affects the reliability of the piezoelectric actuator substrate 40.

  As a structure for discharging the liquid, there are a pressurizing chamber 10 and a discharge hole 8. 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 4h and further blocked by the nozzle plate 4i (parts other than the discharge holes 8). It is made up of.

  A first individual flow path 12 is connected to the pressurizing chamber body 10 a, and the first individual flow path 12 is connected to the first common flow path 20. The first individual flow path 12 is a circular hole that penetrates the upper cover 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 4f, and is further closed by the upper cover plate 4b on the upper side and the lower cover 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 lower cover plate 4g, and the liquid flows along the groove. The second common flow path 24 is formed by overlapping holes formed in the plates 4c to 4g, and is further closed by the upper cover plate 4b on the upper side and the cover space plate 4h on the lower side.

As for the liquid flow, the liquid supplied to the second integrated flow path 26 enters the pressurizing chamber 10 through the second common flow path 24 and the second individual flow path 14 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 first individual flow path 12 and passes through the first common flow path 20.
After entering, it enters the first integrated flow path 22 and is discharged to the outside of 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 respectively 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. 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 made of, for example, silver-palladium containing glass frit, and has a convex shape with a thickness of about 15 μm. The connection electrode 46 is electrically joined to an electrode provided in the signal transmission unit.

  A common electrode surface electrode (not shown) 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 through conductor (not shown) disposed in the piezoelectric ceramic layer 40a.

  As will be described in detail later, a drive signal is supplied from the control unit 88 to the individual electrode 44 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 almost 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 connected to the common electrode surface electrode formed on the piezoelectric ceramic layer 40a so as to avoid the electrode group composed of the individual electrodes 44 through via holes formed through the piezoelectric ceramic layer 40a. 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 plurality of individual electrodes 44.

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).

  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) 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.

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 time of the natural vibration period of the liquid in the pressurizing 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 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.

  In the present embodiment, the first common flow path 20 and the second common flow path 24 (hereinafter, both may be referred to as a common flow path) extend substantially along the short side direction of the head body 2a. Yes. By doing in this way, compared with the case where the common flow path is extended along the longitudinal direction of the head body 2a, the pressure difference between the discharge holes 8 caused by the pressure loss due to the flow path resistance can be reduced. The liquid can be easily circulated without destroying the meniscus. On the other hand, when the common flow path is extended in the short direction, the number of pressurizing chambers 10 supplied and discharged by one common flow path is relatively reduced, and the amount of liquid flowing in the common flow path is also Relatively less. In addition, the number of common channels increases. Therefore, the width (cross-sectional area) of the common flow path is reduced as compared with the case where the common flow path is extended in the longitudinal direction.

  The damper 28 is provided so as to face the common flow path. However, if the damper 28 is disposed on the side wall, the head main body 2a becomes larger in a plan view. Therefore, the damper 28 is preferably disposed on the upper or lower surface of the common flow path. In particular, when the first flow path member 4 is manufactured by plate lamination, the damper 28 can be easily formed if it is disposed on the upper surface or the lower surface of the common flow path.

The pressurizing chamber 10 extends over a relatively wide area on the upper surface side of the common flow path. Therefore, when the damper 28 is arranged on the upper surface of the common flow path, the design is such that the restriction is increased by arranging the damper 28 so as to avoid the pressurizing chamber 10, or the pressurizing chamber is increased by increasing the number of stacked plates. Instead of reducing the need to avoid 10, it is necessary to design at a higher manufacturing cost. Since neither of them is very preferable, the lower surface of the common flow path is preferable to dispose the damper 28 rather than the upper surface of the common flow path. The damper 28 may be disposed on both the lower surface and the upper surface of the common flow path.

  Since the damper 28 has a larger area, the effect becomes larger. Therefore, the damper chamber 29 is arranged so that the entire lower surface of the common flow path becomes the damper 28. Specifically, the damper chamber 29 has a width equal to or greater than the width of the common flow path, and in the longitudinal direction of the common flow path, there is at least an opening of the flow path connected to the pressurizing chamber 10. A damper chamber 29 is arranged over the entire area.

  The effect of the damper 28 increases as the volume change due to deformation increases. Since the common channel has a shape that is long in one direction, the influence of the width of the common channel is large on the amount of volume change. Therefore, in the present invention, by increasing the width of the damper 28 as follows, the volume change of the damper 28 is increased and the damper effect is enhanced. As described above, the common channel extending in the short direction of the head main body 2a is designed to have a narrow width, and the effect of the damper 28 is reduced. Therefore, the present invention is particularly effective in such a case.

  The details of the invention will be described with reference to FIG. 6 is a partial longitudinal sectional view taken along line XX of FIG. This is a longitudinal section along a direction orthogonal to the first direction, which is the direction in which the first common channel 20 and the second common channel 24 extend. 5 (a) and FIG. 6 appear to have different dimensions. This is because FIG. 5 (a) is a sectional view taken along the bent line VV shown in FIG. Is due to.

  The descender 10b which is a part of the pressurizing chamber 10 includes a columnar descender upper portion 10ba disposed on the pressurizing chamber surface 4-1 side and a columnar descender disposed on the discharge hole surface 4-2 side. It consists of a lower part 10bb. The diameter of descender lower part 10bb is smaller than the diameter of descender upper part 10ba. Further, the center (area center of gravity) of the descender lower part 10bb is arranged on the second common flow path 24 side than the center (area center of gravity) of the descender upper part 10ba, and the wall surface of the descender lower part 10bb on the second common flow path 24 side. Further, the distance from the second common flow path 24 is the same as the wall surface of the descender upper part 10ba on the second common flow path 24 side.

  The shape of the descender upper part 10ba and the descender lower part 10bb may be a conical shape or a trapezoidal conical shape whose cross-sectional area decreases in the direction in which the discharge holes 8 exist. Further, the cross-sectional shape may be a polygonal shape such as a square.

  The position PT of the wall surface on the first common flow path 20 side on the pressurizing chamber surface 4-1 side of the descender 10b is from the position PB of the wall surface on the first common flow path 20 side on the discharge hole surface 4-2 side of the descender 10b. Is also arranged on the first common flow path 20 side. In other words, the position PB is farther than the position PT with respect to the first common flow path 20. Thereby, the first common flow path 20 has a width on the pressure chamber surface 4-1 side of W1T [μm] (the unit may be omitted below), whereas the discharge hole surface 4-2. The width on the side can be made larger than W1T, W1B [μm]. And since the width | variety of the damper 28 can be made larger than W1T, the effect of the damper 28 can be made high.

The first common flow path 20 includes a hole opened in the plates 4c to 4f, a lower surface of the plate 4b that closes the upper side, and an upper surface of the plate 4g that closes the lower side. The planar shape of the holes of the plates 4c to 4e is a rectangular shape having a width of W1T, and the three plates overlap to constitute the second common flow path upper portion 20b. The planar shape of the hole of the plate 4f is a rectangular shape having a width of W1B, and constitutes the second common flow path lower portion 20c. The second common flow path lower part 20c is a wide part wider than the second common flow path upper part 20b, and the second common flow path upper part 20b is a narrow part. The damper chamber 29 is configured by combining a portion where the lower surface of the plate 4g is recessed and a portion where the upper surface of the plate 4h is recessed. The planar shape of each recess is a rectangular shape having a width that is substantially the same as W1B. That is, the damper chamber 29 is formed with the same width as the width W <b> 1 </ b> B on the discharge hole surface 4-2 side of the first common channel 20 over the longitudinal direction of the first common channel 20. Each recess can be formed by half-etching the plates 4g and h.

  In the longitudinal direction of the first common flow path 20, the width of the first common flow path 20 and the damper chamber 29 is set to W1B in a portion where there is no descender 10b or the second individual flow path 14 connected to the descender 10b. It may be further expanded. By doing so, the effect of the damper 28 can be further enhanced.

  More specifically, the width of the first common channel 20 on the pressurizing chamber surface 4-1 side is more specifically the width of the upper surface that is the surface of the first common channel 20 on the pressurizing chamber surface 4-1 side. More specifically, the width of the first common flow path 20 on the discharge hole surface 4-2 side is more specifically the width of the lower surface that is the surface of the first common flow path 20 on the discharge hole surface 4-2 side. That is. Further, the position PT of the wall surface on the first common flow path 20 side on the pressurization chamber surface 4-1 side of the descender 10b is more specifically, on the pressurization chamber surface 4-1 side of the first common flow path 20. It is the position of the wall surface of the descender 10b that goes downward from the same height as the upper surface that is a surface, and the position PB of the wall surface on the first common flow path 20 side on the discharge hole surface 4-2 side of the descender 10b is more Specifically, it is the position of the wall surface of the descender 10b that goes upward from the same height as the lower surface that is the surface on the discharge hole surface 4-2 side of the first common flow path 20.

In order to set the wall surface position PT to the first common flow path 20 side from the wall surface position PB, for example, as follows. The sectional area SB [μm ² ] on the discharge hole surface 4-2 side of the descender 10b is made smaller than the sectional area ST [μm ² ] on the pressurizing chamber surface 4-1 side of the descender 10b. The area centroid of the section on the discharge hole surface 4-2 side of the descender 10b is arranged closer to the second common flow path 24 than the area centroid on the pressurizing chamber surface 4-1 side of the descender 10b. The cross-sectional shape of the descender 10b on the discharge hole surface 4-2 side is made smaller in the width direction of the first common flow path 20 than the cross-sectional shape of the descender 10b on the pressurizing chamber surface 4-1 side. As for this, for example, the cross-sectional area of the descender 10b may not be changed by increasing the shape of the cross-section of the descender 10b on the discharge hole surface 4-2 side in the longitudinal direction of the first common flow path 20. it can. The above methods can also be used in combination.

  If the width of the damper 28 is simply widened, it is possible to reduce the cross-sectional area of the descender 10b as a whole, but this is not preferable because of the following effects. One is that if the cross-sectional area of the whole descender 10b is reduced, the discharge amount of the liquid is reduced and the discharge speed is reduced. The other is that the natural vibration period of the entire pressurizing chamber 10 becomes longer and AL becomes longer. As AL becomes longer, the drive signal becomes longer in proportion to it, so that it becomes difficult to increase the drive frequency, which is the reciprocal of the cycle for sending the drive signal, and it becomes difficult to cope with high-speed printing. In addition, when a single pixel is formed by discharging the liquid in a plurality of times, the length of the drive signal is increased in proportion to AL, and the time interval for discharging each liquid is increased. It becomes difficult for the liquid to be collected in one pixel. It is preferable to reduce the sectional area SB on the discharge hole surface 4-2 side of the descender 10b without changing the sectional area ST on the pressure chamber surface 4-1 side of the descender 10b so that these effects are less likely to occur. . SB is preferably 3/4 or less of ST, more preferably 1/2 or less. However, it is preferable to set SB to be 1/8 or more, more preferably 1/4 or more of ST, so that the effects of the above-described reduction in discharge amount, decrease in discharge speed, and increase in AL value do not increase. The length of the descender lower part 10bb whose cross-sectional area is as small as SB is preferably ½ of the entire length of the descender 10b, more preferably ¼ or less.

In the head body 2 a, a damper 28 is provided on the lower surface of the first common flow path 20. In such a configuration, the channel resistance of the first individual channel 12 that connects the first common channel 20 and the pressurizing chamber 10 connects the second common channel 24 and the pressurizing chamber 10. This is particularly effective when the flow resistance of the second individual flow path 14 is smaller. In such a configuration, the pressure applied by the displacement element 50 leaks more into the first common flow path 20 than the second common flow path 24. Therefore, the first common flow path leaked more than that. By damping the pressure on the 20 side, fluid crosstalk can be suppressed.

  As will be described later, a damper may be provided on the lower surface of the second common flow channel 24, but the width W1B of the lower surface of the first common flow channel 20 which is the common flow channel that is connected by a low flow resistance, With the above configuration, the width W1T of the upper surface of the first common flow path 20 is made larger, and the width W2 of the second common flow path 24, which is the common flow path connected by high flow resistance, is made larger. Thus, the damping effect by changing the shape of the descender lower portion 10bb becomes more effective.

  Note that if the flow resistance of the first individual flow path 12 and the flow resistance of the second individual flow path 14 are approximately the same, the difference in pressure generated in each discharge hole 8 when the liquid is circulated increases. For this reason, it is preferable that the flow path resistances are set to values different by a factor of two or more, and the widened damper 28 is disposed in the common flow path on the lower value side as described above.

  In the head main body 2a, the first individual flow path 12 connected from the first common flow path 20 is connected to the pressurizing chamber main body 10a, and the second individual flow path 14 connected from the second common flow path 24 is , Connected to the descender 10b. That is, in the pressurizing chamber 10, the second common channel 24 is connected to the discharge hole 8 side from the first common channel 20. If it does in this way, it can control that the liquid which circulates through pressurization room 10, and sedimentation of the solid content in a liquid arises. If the part of the pressurizing chamber 10 to which the second common flow path 24 is connected (via the second individual flow path 14) is the descender lower part 10bb, that is, the part where the sectional area of the descender 10b is reduced, the descender lower part 10bb is Including the liquid circulation. By doing so, the flow velocity of the liquid flowing through the descender lower portion 10bb, which is a portion near the discharge hole 8, is increased because the cross-sectional area of the descender lower portion 10bb is small, and sedimentation and the like are less likely to occur.

  Subsequently, another embodiment of the present invention will be described. 7, FIG. 8, and FIG. 9 are partial longitudinal sectional views of head bodies 102a, 202a, and 302a according to other embodiments of the present invention, respectively. The basic configuration of the head main bodies 102a, 202a, 302a is almost the same as that of the head main body 2a shown in FIGS. 7, 8, and 9 are partial vertical cross-sectional views of the same portion as FIG. 6.

  In the head main body 102a of FIG. 7, the descender 110b, which is a part of the pressurizing chamber 110, is arranged on the columnar descender upper portion 110ba disposed on the pressurizing chamber surface 4-1 side and on the discharge hole surface 4-2 side. It consists of a cylindrical descender lower part 110bb arranged. The diameter of descender lower part 110bb is smaller than the diameter of descender upper part 110ba. The center (area center of gravity) of the descender lower part 110bb is arranged on the first common flow path 120 side with respect to the center (area center of gravity) of the descender upper part 110ba, and the wall surface of the descender lower part 110bb on the first common flow path 120 side. Further, the distance from the first common channel 120 is the same as the wall surface of the descender upper part 110ba on the first common channel 120 side.

Accordingly, the position of the wall surface on the second common flow path 124 side on the pressurizing chamber surface 4-1 side of the descender 110b is the position of the wall surface on the second common flow path 124 side on the discharge hole surface 4-2 side of the descender 110b. Further, the second common flow path 124 is disposed. In other words, the wall surface on the second common channel 124 side on the discharge hole surface 4-2 side of the descender 110b with respect to the second common channel 124 is the second wall surface on the pressure chamber surface 4-1 side of the descender 110b. 2 is located farther from the wall surface on the common flow path 124 side. Thus, the second common flow path 124 has a width on the pressure chamber surface 4-1 side of W2T [μm], whereas the width on the discharge hole surface 4-2 side is set to W2B [μm]. Can be bigger. And since the width | variety of the damper 128 can be made larger than W2T, the effect of the damper 128 can be made high. The damper chamber 129 extends over the longitudinal direction of the second common flow path 124.
The second common channel 124 is formed to have the same width as the width W2B on the discharge hole surface 4-2 side.

Also in the head main body 102a, as in the case of the head main body 2a, the damper 128 can be widened and the damper effect can be enhanced by performing the following. The sectional area SB [μm ² ] on the discharge hole surface 4-2 side of the descender 110b is made smaller than the sectional area ST [μm ² ] on the pressurizing chamber surface 4-1 side of the descender 110b. The area centroid of the section on the discharge hole surface 4-2 side of the descender 110b is arranged closer to the first common flow path 120 than the area centroid on the pressurizing chamber surface 4-1 side of the descender 110b. The cross-sectional shape of the descender 110b on the discharge hole surface 4-2 side is made smaller in the width direction of the first common flow path 120 than the cross-sectional shape of the descender 110b on the pressurizing chamber surface 4-1 side. The above methods can also be used in combination.

  In the above-described configuration in which the width of the second common flow path 24 on the discharge hole surface 4-2 side is increased and the width of the damper 128 is increased, the flow resistance of the second individual flow path 14 is the first. This is more effective when it is lower than the channel resistance of the individual channel 12.

  In the head main body 202a of FIG. 8, the descender 210b, which is a part of the pressurizing chamber 210, is arranged on the columnar descender upper portion 210ba disposed on the pressurizing chamber surface 4-1 side and on the discharge hole surface 4-2 side. It consists of a columnar descender lower part 210bb arranged. The diameter of descender lower part 210bb is substantially the same as the diameter of descender upper part 210ba. Further, the center (area center of gravity) of the descender lower part 210bb is arranged closer to the first common flow path 220 than the center (area center of gravity) of the descender upper part 210ba. Further, in order to arrange the descender 10b in this way, the width of the first common flow path 220 on the discharge hole surface 4-2 side is larger than the width of the first common flow path 220 on the pressure chamber surface 4-1 side. It is narrower. That is, the wall surface on the second common flow path 224 side on the discharge hole surface 4-2 side of the first common flow path 220 is arranged at a position farther than the second common flow path 24.

  By adopting such a configuration, the second common flow path has a shape in which the cross-sectional area of the descender 210b is substantially constant (the cross-sectional area becomes narrow within a very short distance between the boundaries of the descender upper part 210ba and the descender lower part 210bb). The width on the discharge hole surface 4-2 side of 224 can be made wider than the width on the pressure chamber surface 4-1 side of the second common flow path 224, and the width of the damper 228 can also be made wider.

  In the head main body 202a, the lower surface of the first common flow path 220 is a damper 328, and the lower surface of the damper 328 is a damper chamber 329. Since the width of the damper 328 is narrower than the width of the damper 228, the effect is lower than that of the damper 328, but the damper effect is obtained.

  Further, the discharge hole 8 is located not at the center of the descender upper part 210ba but at the center of the descender lower part 210bb. By doing so, the liquid discharge amount can be increased and the discharge speed can be increased. In addition, due to manufacturing variations, the influence of the displacement of the discharge hole 8 and the descender lower portion 210bb is less likely to affect the discharge characteristics.

In the head main body 302a of FIG. 9, the descender 310b, which is a part of the pressurizing chamber 310, is arranged on the columnar descender upper portion 310ba disposed on the pressurizing chamber surface 4-1 side and on the discharge hole surface 4-2 side. It consists of a columnar descender lower part 310bb arranged and a columnar descender intermediate part between them. The diameter of descender lower part 310bb is smaller than the diameter of descender upper part 310ba. The diameter of the descender middle part is a value between the diameter of the descender lower part 310bb and the diameter of the descender upper part 310ba. Further, the center (area center of gravity) of the descender lower part 210bb is arranged closer to the first common flow path 220 than the center (area center of gravity) of the descender upper part 210ba. The center (area centroid) of the descender middle part is a position between the center (area centroid) of the descender lower part 310bb and the center (area centroid) of the descender upper part 310ba.

  The position of the wall on the first common flow path 220 side on the discharge hole surface 4-2 side of the descender 310b is greater than the position of the wall on the first common flow path 220 side on the pressurizing chamber surface 4-1 side of the descender 310b. Further, the cross-sectional area of the descender 310b on the discharge hole surface 4-2 side is smaller than the cross-sectional area of the descender 310b on the pressurizing chamber surface 4-1 side. By combining these, in the head main body 302a, the width of the second common channel 324 on the pressure chamber surface 4-1 side is larger than the width of the second common channel 324 on the discharge hole surface 4-2 side. Can be bigger. Specifically, with such a configuration, the width of the damper 428 of the head body 302a can be made wider than the width of the damper 228 of the head body 202a.

DESCRIPTION OF SYMBOLS 1 ... Printer 2 ... Liquid discharge head 2a ... Head main body 4 ... (1st) Channel member 4a-g
4-1 ... pressurizing 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 9A ... Discharge hole row 9B ... Discharge hole row 10, 110, 210 , 310... Pressurizing chambers 10a, 110a, 210a, 310a... Pressurizing chamber bodies 10b, 110b, 210b, 310b.
10ba, 110ba, 210ba, 310ba ... upper part of partial flow path (decender) 10bb, 110bb, 210bb, 310bb ... lower part of partial flow path (decender) 11A ... pressure chamber row 11B ... pressure chamber row DESCRIPTION OF SYMBOLS 12 ... 1st separate flow path 14 ... 2nd separate flow path 20, 120, 220 ... 1st common flow path 20a ... (1st common flow path) Opening 20b, 220d ... 1st 1 Upper common channel 20c, 220c ... Lower first common channel 22 ... First integrated channel 22a ... First integrated channel body 22b ... First connection channel 22c, 22d ... Openings 24, 124, 224, 324 ... (second integrated flow path) 24a ... Openings (of the second common flow path) 124b, 224b, 324b ... Second common flow Road upper part 124c, 224c, 324 ... Lower second common flow path 26 ... Second integrated flow path 26a ... Second integrated flow path body 26b ... Second connection flow path 26c, 26d ... (of the second integrated flow path ) Opening 28, 128, 228, 328, 428 ... Damper 29, 129, 229, 329, 429 ... Damper chamber 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)
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 (13)

A plurality of discharge holes, a plurality of pressure chambers connected to the plurality of discharge holes, a first common channel connected to the plurality of pressure chambers, and a second connected to the plurality of pressure chambers A liquid discharge head including a flow path member having a common flow path and a plurality of pressurization units that pressurize the plurality of pressurization chambers,
The plurality of discharge holes are open to a discharge hole surface which is one main surface of the flow path member,
The plurality of pressurizing chambers are disposed on the pressurizing chamber main surface side that is the other main surface of the flow path member, and extend from the pressurizing chamber main body to the discharge hole surface side. And a partial flow path connected to the discharge hole,
The part where the second common flow path and the pressurizing chamber are connected is located closer to the discharge hole than the part where the first common flow path and the pressurizing chamber are connected,
The wall surface on the first common channel side on the pressure chamber surface side of the partial channel is closer to the first common channel side than the wall surface on the first common channel side on the discharge hole surface side of the partial channel. Located
The discharge hole surface side width of the first common flow path is larger than the pressure chamber surface side width of the first common flow path,
A liquid discharge head, wherein a damper having a width wider than a width of the first common flow path on the pressure chamber surface side is disposed on a wall surface on the discharge hole surface side of the first common flow path. .   2. The liquid discharge head according to claim 1, wherein a cross-sectional area of the partial flow path on the discharge hole surface side is smaller than a cross-sectional area of the partial flow path on the pressure chamber surface side.   The said 2nd common flow path is connected by the site | part by which cross-sectional area is smaller than the said pressurization chamber surface side in the said discharge hole surface side of the said partial flow path. Liquid discharge head. When the flow path member is viewed in plan view,
The plurality of pressurizing chambers are arranged side by side on a virtual line,
The first common flow path is disposed on one side of the imaginary line and extends along the imaginary line,
The said 2nd common flow path is arrange | positioned along the said virtual line while being arrange | positioned on the opposite side to the said 1st common flow path with respect to the said virtual line. The liquid discharge head according to any one of the above.   When the flow path member is viewed in plan, the area centroid of the section of the partial channel on the discharge hole surface side is larger than the area centroid of the section of the partial channel on the pressure chamber surface side. The liquid discharge head according to claim 4, wherein the liquid discharge head is located on a road side.   The flow path member connects a first individual flow path connecting the first common flow path and the pressurizing chamber, and a second individual flow path connecting the second common flow path and the pressurizing chamber. 6. The liquid discharge head according to claim 1, wherein a flow path resistance of the first individual flow path is smaller than a flow path resistance of the second individual flow path. . A plurality of discharge holes, a plurality of pressure chambers connected to the plurality of discharge holes, a first common channel connected to the plurality of pressure chambers, and a second connected to the plurality of pressure chambers A liquid discharge head including a flow path member having a common flow path and a plurality of pressurization units that pressurize the plurality of pressurization chambers,
The plurality of discharge holes are open to a discharge hole surface which is one main surface of the flow path member,
The plurality of pressurizing chambers are disposed on the pressurizing chamber main surface side that is the other main surface of the flow path member, and extend from the pressurizing chamber main body to the discharge hole surface side. And a partial flow path connected to the discharge hole,
The part where the second common flow path and the pressurizing chamber are connected is located closer to the discharge hole than the part where the first common flow path and the pressurizing chamber are connected,
The wall surface on the second common channel side on the pressure chamber surface side of the partial channel is closer to the second common channel side than the wall surface on the second common channel side on the discharge hole surface side of the partial channel. Located
The width of the second common flow path on the discharge hole surface side is larger than the width of the second common flow path on the pressure chamber surface side,
A liquid ejection head characterized in that a damper having a width wider than the width of the second common channel on the pressure chamber surface side is disposed on the wall surface on the ejection hole surface side of the second common channel. .   The liquid discharge head according to claim 7, wherein a cross-sectional area of the partial flow path on the discharge hole surface side is smaller than a cross-sectional area of the partial flow path on the pressure chamber surface side.   9. The second common flow path is connected to a portion of the partial flow path that has a smaller cross-sectional area on the discharge hole surface side than on the pressurization chamber surface side. Liquid discharge head. When the flow path member is viewed in plan view,
The plurality of pressurizing chambers are arranged side by side on a virtual line,
The first common flow path is disposed on one side of the imaginary line and extends along the imaginary line,
The second common flow path is disposed on the opposite side of the imaginary line from the first common flow path, and extends along the imaginary line. The liquid discharge head according to any one of the above.   When the flow path member is viewed in plan, the area centroid of the section of the partial channel on the discharge hole surface side is larger than the area centroid of the section of the partial channel on the pressure chamber surface side. The liquid discharge head according to claim 10, wherein the liquid discharge head is located on a road side.   The flow path member connects a first individual flow path connecting the first common flow path and the pressurizing chamber, and a second individual flow path connecting the second common flow path and the pressurizing chamber. 12. The liquid ejection head according to claim 7, wherein a flow path resistance of the second individual flow path is smaller than a flow path resistance of the first individual 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.

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