JP5960745B2 - Liquid discharge head and recording apparatus - Google Patents

Description

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

  2. Description of the Related Art Conventionally, as a liquid ejection head, a plurality of ejection holes for ejecting liquid and a plurality of pressure units connected to the plurality of ejection holes, respectively, a head body that is long in the first direction, and a plurality of pressure units There is known a control section that controls the driving of the head, and includes a board that is long in the first direction and a first connection section that connects one end of the head body and one end of the board ( For example, refer to FIG.

  In the liquid discharge head described above, the control unit is disposed in contact with the first connection unit, and heat generated by the control unit is dissipated through the first connection unit, and the control unit has an excessive temperature. It is restrained to become.

Special Table 2002-528301

  However, the liquid discharge head described in Patent Document 1 has a configuration in which the heat generated by the control unit is radiated through the first connection unit, and the heat generated by the control unit is on one side of the liquid discharge head. Will be transmitted. As a result, the heat distribution of the head main body varies, and the viscosity of the liquid flowing inside the head main body may vary. Therefore, the discharge characteristics of the liquid discharge head may vary.

  One embodiment of the liquid ejection head of the present invention includes a plurality of ejection holes for ejecting liquid, and a plurality of pressure units connected to the plurality of ejection holes, respectively, and a head body that is long in the first direction; A control unit that controls driving of the plurality of pressure units, and a first connection unit that connects a substrate that is long in the first direction, and one end of the head body and one end of the substrate; And a second connecting portion for connecting the other end of the head body and the other end of the substrate. The control unit is disposed closer to the first connection unit than the center of the substrate. The substrate has a first part located between the first connection part and the control part, and a second part located between the second connection part and the control part. . Further, the thermal resistance per unit length of the first part is higher than the thermal resistance per unit length of the second part.

  One embodiment of the liquid ejection head of the present invention includes a plurality of ejection holes for ejecting liquid, and a plurality of pressure units connected to the plurality of ejection holes, respectively, and a head body that is long in the first direction; A control unit that controls driving of the plurality of pressure units, and a first connection unit that connects a substrate that is long in the first direction, and one end of the head body and one end of the substrate; And a second connecting portion for connecting the other end of the head body and the other end of the substrate. The control unit is disposed closer to the first connection unit than the center of the substrate. Further, the thermal resistance of the first connection part is higher than the thermal resistance of the second connection part.

One embodiment of the liquid ejection head of the present invention includes a plurality of ejection holes for ejecting liquid, and a plurality of pressure units connected to the plurality of ejection holes, respectively, and a head body that is long in the first direction; A first control unit and a second control unit that control driving of the plurality of pressurizing units, and a substrate that is long in the first direction, one end of the head body, and one end of the substrate A first connecting portion to be connected; and a second connecting portion for connecting the other end of the head body and the other end of the substrate. The substrate includes a first ground electrode disposed so as to overlap the first control unit and a second ground electrode disposed so as to overlap the second control unit. The first ground electrode and the second ground electrode are separated by a separation unit.

  One aspect of the recording apparatus of the present invention includes the liquid discharge head according to the present invention and a transport unit that transports a recording medium to the liquid discharge head.

  According to the liquid ejection head of the present invention, the amount of heat transferred to the first connecting portion and the amount of heat transferred to the second connecting portion can be made closer to each other, thereby reducing the possibility of temperature variations in the head body. can do.

FIG. 2A is a side view illustrating a schematic configuration of a printer according to a first embodiment of the present invention. FIG. 2B is a plan view illustrating a schematic configuration of the printer according to the present embodiment. FIG. 3 is a plan view showing a head main body of the liquid ejection head according to the first embodiment of the present invention. FIG. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. 2 and is a diagram in which a part of the structure is omitted for explanation. FIG. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. 2 and is a diagram in which a part of the structure is omitted for explanation. It is a longitudinal cross-sectional view along the II line | wire of FIG. FIG. 2 schematically shows the head body shown in FIG. 1, (a) is a perspective view, and (b) is a side view. 4A and 4B schematically illustrate a head main body of a liquid ejection head according to a second embodiment of the present invention, where FIG. 5A is a perspective view and FIG. FIG. 10 is a perspective view schematically showing a head main body of a liquid ejection head according to a third embodiment of the present invention, and FIG. 9B is a perspective view showing a modification of FIG. 10A and 10B schematically show a head main body of a liquid discharge head according to a fourth embodiment of the present invention, where FIG. 5A is a perspective view, FIG. 5B is a side view, and FIG. FIG. FIG. 10 schematically illustrates a head main body of a liquid ejection head according to a fifth embodiment of the present invention, where (a) is a perspective view and (b) is a side view. FIG. 10 is a side view schematically showing a head main body of a liquid ejection head according to a sixth embodiment of the present invention, and (b) is a side view showing a modification of (a).

<First Embodiment>
FIG. 1A is a schematic side view of a printer 1 (color ink jet) which is a recording apparatus including a liquid discharge head 2 according to an embodiment of the present invention. FIG. 1B is a schematic plan view of the printer 1. In the drawing, X indicates the first direction, Y in the drawing indicates the sub-scanning direction, and Z in the drawing indicates the thickness direction.

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 device 88 controls the liquid ejection head 2 based on image and character data, ejects liquid from the liquid ejection head 2 toward the recording medium P, and causes droplets to land on the printing paper P. Recording such as printing on the printing paper P is performed.

  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 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. A portion of the liquid discharge head 2 that discharges the liquid faces the printing paper P. 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 may be called a longitudinal direction, and is the first direction X of the present invention. 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, in 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 direction that intersects the conveyance direction of the printing paper P is the sub-scanning direction Y.

  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). If such ink is printed under the control of the control device 88, a color image can be printed.

  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 the printing paper P. 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, 75 m / min. Each roller may be controlled by the control device 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 device 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 or discharge speed) 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, a liquid discharge head 2 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 (a) shows a schematic structure, and FIG. 2 (b) shows regions divided according to the role they play. In FIG. 3, for the sake of explanation, some of the flow paths are omitted. 4 is an enlarged plan view at the same position as that in FIG. 3, and a part of the flow path different from that in FIG. 3 is omitted. In FIGS. 3 and 4, for easy understanding of the drawings, the pressurizing chamber 10, the squeezing 6, the discharge holes 8, and the like that are to be drawn by broken lines below the piezoelectric actuator substrate 21 are drawn by solid lines. In FIG. 6, the signal transmission unit 60 drawn from the head body 2a is not shown.

  As shown in FIG. 6, the liquid ejection head 2 includes a head body 2 a, a wiring board 90, a first connection part 96, a second connection part 98, a control part 92, and a heat conduction plate 94. Yes.

  The head body 2a includes a flow path member 4 and a piezoelectric actuator substrate 21 in which a displacement element 30 is formed. The liquid discharge head 2 may include a reservoir that supplies liquid to the head main body 2a, a cover member that protects the head main body 2, or a metal housing.

  The flow path member 4 constituting the head body 2a includes a manifold 5 which is a common flow path, a plurality of pressurizing chambers 10 connected to the manifold 5, and a plurality of discharge holes respectively connected to the plurality of pressurizing chambers 10. 8 and. The plurality of discharge holes 8 are opened at the lower surface of the flow path member 4, and the upper surface of the flow path member 4 is a discharge hole surface 4-1. The pressurizing chamber 10 opens to the upper surface of the flow path member 4, and the upper surface of the flow path member 4 is a pressurizing chamber surface 4-2. The upper surface of the flow path member 4 has an opening 5a connected to the manifold 5, and the liquid is supplied from the opening 5a.

  In addition, a piezoelectric actuator substrate 21 including a displacement element 30 is bonded to the pressure chamber surface 4-2 of the flow path member 4, and each displacement element 30 is disposed so as to be positioned on the pressure chamber 10. Yes.

The piezoelectric actuator substrate 21 has an FP for supplying a signal to each displacement element 30.
A signal transmission unit 60 such as C (Flexible Printed Circuit) is connected. In FIG. 2, the outline of the vicinity of the signal transmission unit 60 connected to the piezoelectric actuator substrate 21 is indicated by a dotted line so that the two signal transmission units 60 are connected to the piezoelectric actuator substrate 21. The electrodes formed in the signal transmission unit 60 are electrically connected to the piezoelectric actuator substrate 21 and are disposed in a rectangular shape at the end of the signal transmission unit 60. The two signal transmission units 60 are connected so that the respective ends thereof come to the center of the piezoelectric actuator substrate 21 in the sub-scanning direction Y. The two signal transmission parts 60 extend from the central part toward the long side of the piezoelectric actuator substrate 21.

  The signal transmission unit 60 is electrically connected to a wiring board 90 provided outside the head body 2a. In FIG. 6, the signal transmission unit 60 is omitted.

  The head body 2 a has one piezoelectric actuator substrate 21 including a flat plate-like flow path member 4 and a displacement element 30 connected on the flow path member 4. The planar shape of the piezoelectric actuator substrate 21 is rectangular, and the piezoelectric actuator substrate 21 is disposed on the pressurizing chamber surface 4-2 of the flow path member 4 so that the long side of the rectangle is along the first direction X.

  The flow path member 4 includes a manifold 5, a plurality of pressurizing chambers 10, and a plurality of discharge holes 8 connected to the plurality of pressurizing chambers 10. The manifold 5 is connected in common to the plurality of pressurizing chambers 10, and the manifold 5 and the pressurizing chamber 10 are connected by an individual supply channel 14. The pressurizing chamber 10 and the discharge hole 8 are connected by an individual flow path 12.

  The flow path member 4 includes a side wall 15a, a first partition 15b, and a second partition 15c. The side wall 15a is disposed at both ends of the flow path member 4 in the sub-scanning direction Y, and the second partition wall 15c is disposed at the center in the sub-scanning direction Y. A manifold 5 is formed between the side wall 15a and the second partition wall 15c. The manifold 5 has an elongated shape extending from one end side in the first direction X to the other end side, and a manifold opening 5 a that is open on the upper surface of the flow path member 4 is formed at both ends. ing.

  The manifold 5 includes a plurality of sub-manifolds 5 b that are partitioned by the first partition 15 b of the flow path member 4. The sub-manifold 5b is provided so as to extend along the first direction. The first partition 15b has the same height as the manifold 5 in the central portion in the first direction X, which is a region connected to the pressurizing chamber 10, and the manifold 5 is completely partitioned into a plurality of sub-manifolds 5b. Yes. By doing in this way, the partial flow path 12 connected to the pressurization chamber 10 from the discharge hole 8 and the discharge hole 8 can be provided so that it may overlap with the 1st partition 15b when planarly viewed.

  In the present embodiment, two manifolds 5 are provided independently, and openings 5a are provided at both ends. One manifold 5 is provided with seven first partition walls 15b, which are divided into eight sub-manifolds 5b. The width of the sub-manifold 5b is larger than the width of the first partition wall 15b, so that a large amount of liquid can flow through the sub-manifold 5b.

The seven first partitions 15b are longer in length as they are closer to the center in the sub-scanning direction Y, and the first partitions are closer to the center in the sub-scanning direction Y at both ends of the manifold 5 in the sub-scanning direction Y. About 15b, the end of the first partition 15b is closer to the end of the manifold 5. As a result, a balance is established between the channel resistance generated by the outer wall of the manifold 5 and the channel resistance generated by the first partition wall 15b, and each of the sub-manifolds 5b is a part connected to the pressurizing chamber 10. The pressure difference of the liquid at the end of the region where the supply channel 14 is formed can be reduced. Since the pressure difference in the individual supply flow path 14 leads to a pressure difference applied to the liquid in the pressurizing chamber 10, discharge variation can be reduced by reducing the pressure difference in the individual supply flow path 14.

  The plurality of pressurizing chambers 10 are two-dimensionally expanded in the first direction X and the sub-scanning direction Y. The pressurizing chamber 10 is a hollow region having a substantially rhombic or elliptical planar shape with rounded corners.

  As shown in FIGS. 3 to 5, the pressurizing chamber 10 is connected to one sub-manifold 5 b via an individual supply channel 14. Along with one sub-manifold 5b, two pressurizing chamber rows 11, which are rows of pressurizing chambers 10 connected to the sub-manifold 5b, are provided on each side of the sub-manifold 5b, for a total of two rows. Yes. Accordingly, 16 rows of pressurizing chambers 11 are provided for one manifold 5, and 32 heads of pressurizing chambers 11 are provided in the entire head body 2a. The intervals in the first direction X of the pressurizing chambers 10 in the respective pressurizing chamber rows 11 are the same, and can be, for example, 37.5 dpi.

  One column of dummy pressurizing chambers 16 is provided at the end of each pressurizing chamber row 11. The dummy pressurizing chambers 16 in the dummy pressurizing chamber row are connected to the manifold 5 but are not connected to the discharge holes 8. Further, one dummy pressurizing chamber row in which dummy pressurizing chambers 16 are arranged in a straight line is provided outside the 32 pressurizing chamber rows 11. The dummy pressurizing chamber 16 in this dummy pressurizing chamber row is not connected to either the manifold 5 or the discharge hole 8. By these dummy pressurizing chambers 16, the structure (rigidity) around the pressurizing chamber 10 one inner side from the end is close to the structure (rigidity) of the other pressurizing chambers 10, so that the difference in liquid ejection characteristics can be reduced. Less.

  In addition, since the influence of the difference of the surrounding structure has a large influence of the pressurizing chamber 10 adjacent to the first direction X that is close to the distance, dummy pressurizing chambers are provided at both ends in the first direction X. Since the influence of the sub-scanning direction Y is relatively small, it is provided only on the side closer to the end of the head body 2a. Thereby, the width | variety of the head main body 2a can be made small.

  The pressurizing chamber 10 connected to one manifold 5 is arranged on a lattice that forms rows and columns along each outer side of the rectangular piezoelectric actuator substrate 21. As a result, the individual electrodes 25 formed on the pressurizing chamber 10 are arranged at equal distances from the outer side of the piezoelectric actuator substrate 21. Therefore, when forming the individual electrodes 25, the piezoelectric actuator substrate is formed. 21 can be hardly deformed. When the piezoelectric actuator substrate 21 and the flow path member 4 are joined, if this deformation is large, stress may be applied to the displacement element 30 near the outer side, resulting in variations in displacement characteristics. However, by reducing the deformation, The variation can be reduced.

  In addition, since the dummy pressurizing chamber row of the dummy pressurizing chamber 16 is provided outside the pressurizing chamber row 11 closest to the outer side, the influence of deformation can be made less susceptible. The pressurizing chambers 10 belonging to the pressurizing chamber row 11 are arranged at equal intervals, and the individual electrodes 25 corresponding to the pressurizing chamber rows 11 are also arranged at equal intervals. The pressurizing chamber rows 11 are arranged at equal intervals in the sub-scanning direction Y, and the rows of the individual electrodes 25 corresponding to the pressurizing chamber rows 11 are also arranged at equal intervals in the sub-scanning direction Y. Thereby, it is possible to eliminate a portion where the influence of the crosstalk becomes particularly large.

  In the present embodiment, the pressurizing chambers 10 are arranged in a lattice shape, but the pressurizing chambers 10 in adjacent pressurizing chamber rows 11 may be arranged in a staggered manner so as to be positioned between each other. By doing so, the distance between the pressurizing chambers 10 belonging to the adjacent pressurizing chamber rows 11 becomes longer, so that crosstalk can be further suppressed.

Regardless of how the pressurizing chamber rows 11 are arranged, when the flow path member 4 is viewed in plan, the pressurizing chamber 10 belonging to one pressurizing chamber row 11 is added to the adjacent pressurizing chamber row 11. By disposing the pressure chamber 10 and the liquid ejection head 2 so as not to overlap in the first direction X, crosstalk can be suppressed. On the other hand, when the distance between the pressurizing chamber rows 11 is increased, the width of the liquid discharge head 2 is increased, so that the accuracy of the installation angle of the liquid discharge head 2 relative to the printer 1 and the use of a plurality of liquid discharge heads 2 are increased. The influence of the relative position accuracy of the liquid discharge head 2 on the printing result is increased. Therefore, by making the width of the first partition wall 15b smaller than that of the sub-manifold 5b, the influence of the accuracy on the printing result can be reduced.

  The pressurizing chambers 10 connected to one sub-manifold 5 b form two rows of pressurizing chambers 11, and the discharge holes 8 connected from the pressurizing chambers 10 belonging to one pressurizing chamber row 11 have one discharge hole 8. A discharge hole row 9 is formed. The discharge holes 8 connected to the pressurizing chambers 10 belonging to the two pressurizing chamber rows 11 open to different sides of the sub-manifold 5b. In FIG. 4, two discharge hole rows 9 are provided in the first partition wall 15 b, but the discharge holes 8 belonging to the respective discharge hole rows 9 are pressurized against the sub-manifold 5 b near the discharge holes 8. It is connected via the chamber 10.

  If the discharge hole 8 connected to the adjacent sub-manifold 5b via the pressurizing chamber row 11 and the liquid discharge head 2 are arranged so as not to overlap in the first direction X, the pressurizing chamber 10 and the discharge hole 8 Since crosstalk between the flow paths connecting the two can be suppressed, crosstalk can be further reduced. If the entire flow path connecting the pressurizing chamber 10 and the discharge hole 8 is arranged so as not to overlap in the first direction X of the liquid discharge head 2, crosstalk can be further reduced.

  A plurality of pressurizing chambers (not shown) are constituted by a plurality of pressurizing chambers 10 connected to one manifold 5, and since there are two manifolds 5, two pressurizing chamber groups are formed. The arrangement of the pressurizing chambers 10 related to the discharge in each pressurizing chamber group has the same shape, and is arranged at a position translated in the sub-scanning direction Y. These pressurizing chambers 10 are arranged over substantially the entire surface of the upper surface of the flow path member 4 in a region facing the piezoelectric actuator substrate 21, although there are portions where the gaps are slightly wide, such as between the pressurizing chamber groups. . That is, the pressurizing chamber group formed by these pressurizing chambers 10 occupies a region having substantially the same shape as the piezoelectric actuator substrate 21. Further, the opening of each pressurizing chamber 10 is closed by bonding the piezoelectric actuator substrate 21 to the pressurizing chamber surface 4-2 of the flow path member 4.

  The individual flow path connected to the discharge hole 8 opened on the discharge hole surface 4-1 on the lower surface of the flow path member 4 from the corner facing the corner to which the individual supply flow path 14 of the pressurizing chamber 10 is connected. 12 is growing. The individual flow path 12 extends in a direction away from the pressurizing chamber 10 in plan view. More specifically, the pressurizing chamber 10 extends away from the direction along the long diagonal line while being shifted to the left and right with respect to that direction. As a result, the discharge chambers 8 can be arranged at intervals of 1200 dpi as a whole, while the pressurization chambers 10 are arranged in a lattice pattern in which the intervals within the pressurization chamber rows 11 are 37.5 dpi.

In other words, when the discharge holes 8 are projected so as to be orthogonal to the virtual straight line parallel to the first direction X of the flow path member 4, each of the discharge holes 8 is in the range of R of the virtual straight line shown in FIG. That is, 16 discharge holes 8 connected to the manifold 5 and a total of 32 discharge holes 8 are equally spaced at 1200 dpi. Accordingly, by supplying the same color ink to all the manifolds 5, it is possible to form an image with a resolution of 1200 dpi in the first direction X as a whole. Further, one discharge hole 8 connected to one manifold 5 is equally spaced at 600 dpi within the range of R of the imaginary straight line. As a result, by supplying different colors of ink to the respective manifolds 5, it is possible to form two-color images with a resolution of 600 dpi in the first direction X as a whole. In this case, if two liquid ejection heads 2 are used, an image of four colors can be formed at a resolution of 600 dpi, and printing accuracy is higher and printing settings are easier than using a liquid ejection head capable of printing at 600 dpi. Can be. Note that the range of the imaginary straight line R is covered by the discharge holes 8 connected to the pressurizing chambers 10 belonging to the one pressurizing chamber row aligned in the sub-scanning direction Y of the head body 2a.

  As shown in FIG. 5, the flow path member 4 has a laminated structure in which a plurality of plates are laminated. These plates are a cavity plate 4a, a base plate 4b, an aperture plate 4c, a supply plate 4d, manifold plates 4e to 4j, a cover plate 4k, and a nozzle plate 4l in order from the upper surface of the flow path member 4.

  A number of holes are formed in these plates. Since the thickness of each plate is about 10 to 300 μm, the formation accuracy of the holes to be formed can be increased. The thickness of the flow path member 4 is about 500 μm to 2 mm. Each plate is aligned and laminated so that these holes communicate with each other to form the individual flow path 12 and the manifold 5.

  The holes formed in each plate will be described. These holes include the following. The first is the pressurizing chamber 10 formed in the cavity plate 4a. Second, there is a communication hole that constitutes an individual supply channel 14 that is connected from one end of the pressurizing chamber 10 to the manifold 5. This communication hole is formed in each plate from the base plate 4b (specifically, the inlet of the pressurizing chamber 10) to the supply plate 4c (specifically, the outlet of the manifold 5). The individual supply flow path 14 includes a squeeze 6 that is formed in the aperture plate 4c and is a portion where the cross-sectional area of the flow path is small.

  Third, there is a communication hole that forms a partial flow path 12 that communicates with the discharge hole 8 from the other end opposite to the end to which the individual supply path 14 of the pressurizing chamber 10 is connected. The partial flow path 12 is formed in each plate from the base plate 4b (specifically, the outlet of the pressurizing chamber 10) to the nozzle plate 4l (specifically, the discharge hole 8).

  Fourth, there is a communication hole constituting the sub-manifold 5b. The communication holes are arranged at the same positions of the manifold plates 4e to 4j in a plan view, and a space is provided so as to spread in the thickness direction Z, thereby forming a sub-manifold 5b.

  The first to fourth communication holes are connected to each other, and the liquid supplied from the manifold 5 is discharged from the discharge hole 8. The liquid supplied to the manifold 5 is discharged from the discharge hole 8 through the following path. First, from the manifold 5, it enters the individual supply flow path 14 and reaches one end of the throttle 6. Next, it proceeds horizontally along the extending direction of the restriction 6 and reaches the other end of the restriction 6. From there, it reaches one end of the pressurizing chamber 10 upward. Furthermore, it progresses horizontally along the extending direction of the pressurizing chamber 10 and reaches the other end of the pressurizing chamber 10. The liquid that has entered the descender from the pressurizing chamber 10 moves in the horizontal direction and is mainly directed downward and reaches the discharge hole 8 opened in the lower surface, and is discharged to the outside.

  The piezoelectric actuator substrate 21 includes piezoelectric ceramic layers 21a and 21b, a common electrode 24, an individual electrode 25, a connection electrode 26, and a common electrode surface electrode 28. When a voltage is applied from the outside, the piezoelectric ceramic layer 21b sandwiched between the common electrode 24 and the individual electrode 25 is displaced to pressurize the pressurizing chamber 10.

  In the piezoelectric actuator substrate 21, a piezoelectric ceramic layer 21a, a common electrode 24, and a piezoelectric ceramic layer 21b are laminated in this order on the pressure chamber surface 4-2. An individual electrode 25, a connection electrode 26, and a common electrode surface electrode 28 are formed on the piezoelectric ceramic layer 21b.

The common electrode 24 is disposed so as to be sandwiched between the piezoelectric ceramic layers 21a and 21b, and is formed over substantially the entire area of the piezoelectric actuator substrate 21 in the first direction X and the sub-scanning direction Y. The thickness of the common electrode 24 can be about 2 μm. The common electrode 24 is grounded and held at the ground potential.

  The individual electrode 25 is formed at a position facing each pressurizing chamber 10. The individual electrode 25 includes an individual electrode body 25a that is slightly smaller than the pressurizing chamber 10 and has a shape substantially similar to the pressurizing chamber 10, and an extraction electrode 25b that is extracted from the individual electrode body 25a. In the same manner as the pressurizing chamber 10, the individual electrode 25 constitutes an individual electrode row and an individual electrode group.

  The common electrode surface electrode 28 is electrically connected to the common electrode 24 through a via hole (not shown) disposed in the piezoelectric ceramic layer 21b. The common electrode surface electrode 28 is formed in two rows along the first direction X at the center of the piezoelectric actuator substrate 21 in the sub-scanning direction Y, and in the sub-scanning direction Y near the end of the first direction X. One row is formed along the line. Although the illustrated common electrode surface electrode 28 is intermittently formed on a straight line, it may be formed continuously on a straight line.

  The connection electrode 26 is electrically connected to the extraction electrode 25 b of the individual electrode 25, and the signal transmission unit 60 is electrically connected to the piezoelectric actuator substrate 21 via the connection electrode 26. Thereby, the signal transmission part 60 and the piezoelectric actuator board | substrate 21 can be connected easily. The connection electrode 26 has a thickness of about 15 μm and is formed in a convex shape.

  A common electrode connection electrode electrically connected to the common electrode surface electrode 28 may be provided. At this time, if the area of the common electrode surface electrode 28 and the common electrode connection electrode is made larger than the area of the connection electrode 26, the end of the signal transmission unit 60 (the end of the piezoelectric actuator substrate 21 and the end of the piezoelectric actuator substrate 21 in the first direction X). ) Can be made stronger by the connection on the common electrode surface electrode 28, so that the signal transmission part 60 can hardly be peeled off from the end.

  A portion sandwiched between the individual electrode 25 and the common electrode 24 of the piezoelectric ceramic layer 21b is polarized in the thickness direction, and becomes a displacement element 30 having a unimorph structure that is displaced when a voltage is applied to the individual electrode 25. Yes. More specifically, when an electric field is applied in the polarization direction to the piezoelectric ceramic layer 21a by setting the individual electrode 25 to a potential different from that of the common electrode 24, an active portion where the electric field is applied is distorted by the piezoelectric effect. Work as.

  In this configuration, when the control device 88 sets the individual electrode 25 to a predetermined positive or negative potential with respect to the common electrode 24 so that the electric field and the polarization are in the same direction, the 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 30 is driven (displaced) by a drive signal supplied to the individual electrode 25 through the control unit 94 under the control of the control device 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 25 is set to a potential higher than the common electrode 24 (hereinafter referred to as a high potential) in advance, and the individual electrode 25 is once set to the same potential as the common electrode 24 (hereinafter referred to as a low potential) each time there is a discharge request, and then a predetermined potential is set. At this timing, the potential is set again. As a result, the piezoelectric ceramic layers 21a and 21b return to a flat shape at the timing when the individual electrode 25 becomes a low potential, and the volume of the pressurizing chamber 10 increases compared to the initial 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 substantially zero. Next, the volume of the pressurizing chamber 10 begins to decrease, and the pressure increases. Thereafter, the individual electrode 25 is set to a high potential at the timing when 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 driving signal that is a low potential for a certain period with the high potential as a reference to the individual electrode 25. 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.

  As shown in FIG. 6, the liquid ejection head 2 includes a head body 2 a, a wiring board 90, a first connection part 96, and a second connection part 98. The head main body 2a is disposed with the discharge hole surface 4-1 (see FIG. 5) as the lower surface and the pressurizing chamber surface 4-2 (see FIG. 5) as the upper surface. On the head main body 2 a, two wiring boards 90 are arranged in an upright state, and are fixed by a first connection portion 96 and a second connection portion 98.

  The wiring board 90 is long in the first direction X and includes a control unit 92 and a heat conduction plate 94. The wiring board 90 has a rectangular shape. Here, being long in the first direction X means that the long side of the wiring board 90 is longer in the first direction X than the short side. Wiring is patterned inside the wiring board 90, and various electronic components mounted on the wiring board 90 are electrically connected. The control unit 92 is provided on the wiring substrate 90 and is disposed closer to the first connection unit 96 than the central portion of the wiring substrate 90 in the first direction X. The heat conductive plate 94 is provided in contact with the first connection portion 96, the control portion 92, and the second connection portion 98.

  The wiring board 90 includes a first part 90 a located between the first connection part 96 and the control part 92, and a second part 90 b located between the second connection part 98 and the control part 92. Yes. In the liquid discharge head 2, the width in the thickness direction Z of the first portion 90a of the wiring board 90 and the width in the thickness direction Z of the second portion 90b of the wiring board 90 are substantially the same length, and the unit length The thermal resistance per hit is equal.

  The control unit 92 is mounted on the wiring board 90 in order to control the driving of the head main body 2a. The control unit 92 includes a digital circuit unit that performs signal processing of print data and the like, and an analog circuit unit that drives the displacement element 30 (see FIG. 5). As the digital circuit portion, a driver IC such as a microcomputer can be exemplified, and as the analog circuit portion, a linear regulator for adjusting a voltage can be exemplified. When the head main body 2a is driven, the control unit 92 generates heat as it is driven.

  The heat conducting plate 94 is provided so as to contact the first connecting portion 96, the control portion 92, and the second connecting portion 98, and is provided so as to extend in the first direction X. The heat conduction plate 94 has a function of transferring heat generated by the control unit 92 to the first connection unit 96 and the second connection unit 98. And it has the 1st site | part 94a located between the 1st connection part 96 and the control part 92, and the 2nd site | part 94b located between the 2nd connection part 98 and the control part 92. The heat conductive plate 94 can be formed of, for example, a metal or an alloy.

  In the present embodiment, in the cross section along the sub-scanning direction Y, the heat conducting plate 94 has a configuration in which the cross-sectional area of the first part 94a is smaller than the cross-sectional area of the second part 94b. Thereby, the thermal resistance of the 1st site | part 94a can be made higher than the thermal resistance of the 2nd site | part 94b.

  The first connection part 96 is arranged in a standing state on the head main body 2 a and is provided so as to extend in the thickness direction Z. The first connection portion 96 is provided so as to be in contact with one main surface of the wiring board 90 and protrudes upward from the wiring board 90. The first connection portion 96 connects one end portion of the head main body 2 a and one end portion of the wiring board 90 in the first direction X. Therefore, heat generated in the wiring board 90 can be conducted to the head body 2a.

  The second connection part 98 is arranged in a state of being erected on the head main body 2a, and is provided so as to extend in the thickness direction Z. The second connection part 98 is provided so as to be in contact with one main surface of the wiring board 90, and protrudes upward from the wiring board 90. The second connection portion 98 connects the other end of the head body 2 a and the other end of the wiring substrate 90 in the first direction X. Therefore, heat generated in the wiring board 90 can be conducted to the head body 2a.

  The first connection portion 96 and the second connection portion 98 are formed with a certain width in the thickness direction Z. Therefore, the thermal resistance per unit length of the 1st connection part 96 and the 2nd connection part 98 is constant.

  The 1st connection part 96 and the 2nd connection part 98 can be formed with a metal or an alloy, for example. Moreover, the 1st connection part 96 and the 1st site | part 94a are connected by the 1st connection part 95a. Moreover, the 2nd connection part 98 and the 2nd site | part 94b are connected by the 2nd connection part 95b. Although not shown, the first connection portion 96 and the second connection portion 98 are connected to the head main body 2a and the wiring board 90 by screwing. The 1st connection part 95a and the 2nd connection part 95b can be connected by welding, for example. These members may be connected not by screwing but by welding or an adhesive.

  Since the wiring board 90 includes the heat conduction plate 94 that contacts the first connection portion 96, the control portion 92, and the second connection portion 98, the heat generated in the control portion 92 is first connected by the heat conduction plate 94. Heat can be efficiently transferred to the portion 96 and the second connection portion 98.

  Here, the control unit 92 may not be arranged at the center portion in the first direction X of the wiring board 90 due to the routing of the wiring board 90 or the problem of the arrangement space. For example, in the first direction X, when the control unit 92 is disposed on the first connection unit 96 side with respect to the central portion of the wiring board 90, the amount of heat conducted through the first connection unit 96 to the head body 2a is increased. There is a possibility that the amount of heat transmitted through the second connection portion 98 to the head main body 2a is larger than that. Thereby, the temperature on one side of the head main body 2a becomes higher than the temperature on the other side of the head main body 2a, and the temperature distribution of the head main body 2a may vary in the first direction X. As a result, the viscosity of the liquid flowing in the head main body 2a varies, and the ejection characteristics of the head main body 2a may vary.

  On the other hand, in the liquid discharge head 2, the heat conducting plate 94 has a configuration in which the cross-sectional area of the first portion 94a is smaller than the cross-sectional area of the second portion 94b in the cross section along the sub-scanning direction Y. Yes. That is, the heat resistance per unit length of the first portion 94a of the heat conducting plate 94 is higher than the heat resistance per unit length of the second portion 94b of the heat conducting plate 94. For this reason, it becomes difficult for the heat of the control part 92 to conduct heat through the first portion 94a. As a result, the amount of heat conducted through the heat conducting plate 94 to the head main body 2a can be made uniform, and the possibility of variations in the temperature distribution of the head main body 2a can be reduced.

  That is, the heat generated in the control unit 92 is transmitted to one side of the head body 2a through the first part 94a and the first connection part 96 (hereinafter referred to as the first path), the second part 94b and the second part 94b. The second path (hereinafter referred to as the second path) transmitted to the other side of the head main body 2a through the two connection portions 98 is thermally conducted and supplied to the head main body 2a. Since the heat resistance per unit length of the first portion 94a of the conductive plate 94 is higher than the heat resistance per unit length of the second portion 94b of the heat conductive plate 94, the first path and The amount of heat conducted through the second path can be made close to uniform, and the possibility of variations in the temperature distribution of the head body 2a can be reduced.

  The thermal resistance per unit length indicates the thermal resistance per unit length of the first path and the second path. For example, the thermal resistance per unit length of the heat conducting plate 94 is the first direction. The thermal resistance per unit length of X is shown.

  The control unit 92 includes an analog circuit unit and a digital circuit unit, and a plurality of the control units 92 may be provided on the wiring board 90. The analog circuit portion is higher in applied voltage and more likely to generate noise than the digital circuit portion. Further, the digital circuit unit is arranged at a position away from the arrangement region of the analog circuit unit. Therefore, for example, the analog circuit part is disposed in the first part 90 a on one side of the wiring board 90, and the digital circuit part is disposed in the second part 90 b on the other side of the wiring board 90.

  And the linear regulator which comprises an analog circuit part lowers the voltage input with the power supply voltage to the predetermined voltage, and supplies it to the displacement element 30. FIG. Therefore, the difference in voltage is consumed by generating heat. As a result, the heat generated by the control unit 92 is concentrated at the first portion 90 a of the wiring board 90.

  Also in this case, in the liquid discharge head 2, the thermal resistance per unit length of the first portion 94a of the heat conducting plate 94 is higher than the thermal resistance per unit length of the second portion 94b of the heat conducting plate 94. Since it has a configuration, the amount of heat conducted to the head main body 2a can be made uniform.

  In the cross section along the sub-scanning direction Y, the heat conducting plate 94 has a configuration in which the cross-sectional area of the first part 94a is smaller than the cross-sectional area of the second part 94b. Thereby, the thermal resistance of the 1st site | part 94a can be made higher than the thermal resistance of the 2nd site | part 94b. That is, since the first portion 94a and the second portion 94b of the heat conducting plate 94 are formed of the same material, the first portion 94a having a small mass has a higher thermal resistance than the second portion 94b having a large mass. It will be. As a result, the possibility of variations in the temperature distribution of the head main body 2a can be reduced.

In the liquid ejection head 2, an example in which the width in the thickness direction Z of the first portion 94a is smaller than the width in the thickness direction Z of the second portion 94b is shown, but the present invention is not limited to this. For example, the thickness of the first part 94a in the sub-scanning direction Y may be smaller than the thickness of the second part 94b in the sub-scanning direction Y. Even in this case, the cross-sectional area of the first part 94a can be made smaller than the cross-sectional area of the second part 94b.

  Further, the width of the first portion 94a in the thickness direction Z is smaller than the width of the second portion 94b in the thickness direction Z, and the thickness of the first portion 94a in the sub-scanning direction Y is sub-scanned in the second portion 94b. The thickness may be smaller than the thickness in the direction Y. In that case, the thermal resistance of the first part 94a can be made higher than the thermal resistance of the second part 94b, and the possibility of variation in temperature distribution in the head body 2a can be reduced.

  The liquid ejection head 2 has a configuration in which the heat conductive plate 94 is connected to the first connection part 96 by the first connection part 95a and is connected to the second connection part 98 by the second connection part 95b. . The distance between the first connecting portion 95a and the head main body 2a is longer than the distance between the second connecting portion 95b and the head main body 2a.

  Therefore, the length of the first connection part 96 located between the first connection part 95a and the head body 2a is larger than the length of the second connection part 98 located between the second connection part 95b and the head body 2a. The thermal resistance per unit length of the first path is higher than the thermal resistance per unit length of the second path. As a result, the amount of heat transmitted through the first connection portion 96 can be made smaller than the amount of heat transmitted through the second connection portion 98, and the possibility of variations in the temperature distribution of the head body 2a can be reduced.

  The distance between the first connecting portion 95a and the head main body 2a indicates the distance from the lower end of the first connecting portion 95a to the head main body 2a, and the distance between the second connecting portion 95b and the head main body 2a is also shown. It is the same.

<Second Embodiment>
The liquid discharge head 102 will be described with reference to FIG. The liquid discharge head 102 does not include the heat conductive plate 94 (see FIG. 6), and the shape of the wiring board 190 is different from the shape of the wiring board 90. The same members as those of the liquid discharge head 2 are denoted by the same reference numerals, and so on.

  The wiring board 190 includes a first part 190a and a second part 190b, and the length of the first part 190a in the thickness direction Z is shorter than the length of the second part 190b in the thickness direction Z. ing. The wiring board 190 can be formed by cutting out a part of a rectangular wiring board.

  The liquid discharge head 102 has a configuration in which the thermal resistance per unit length of the first portion 190 a of the wiring board 190 is higher than the thermal resistance per unit length of the second portion 190 b of the wiring board 190. For this reason, the first portion 190a of the wiring board 190 is configured not to conduct heat. As a result, the heat generated in the control unit 92 is less likely to conduct heat through the first portion 190a, and the amount of heat transmitted through the first path and the amount of heat transmitted through the second path can be made closer to each other. Therefore, it is possible to reduce the possibility of temperature variations in the head main body 2a. Thus, it is not always necessary to provide the heat conductive plate 94.

  Further, the wiring board 190 has a configuration in which the cross-sectional area of the first part 190a is smaller than the cross-sectional area of the second part 190b in the cross section along the sub-scanning direction Y. As a result, the amount of heat transmitted through the first part 190a and the amount of heat transmitted through the second part 190b can be made closer to each other. This can reduce the possibility of variations in temperature distribution in the head body 2a.

Note that the cross-sectional area of the first portion 190a in the cross section along the sub-scanning direction Y is set by making the thickness of the first portion 190a in the sub-scanning direction Y smaller than the thickness of the second portion 190b in the sub-scanning direction Y. However, it may be smaller than the cross-sectional area of the second portion 190b. In that case, the same effect can be obtained.

<Third Embodiment>
The liquid discharge head 202 will be described with reference to FIG. In the liquid discharge head 202, the shape of the second connection portion 298 is different from the second connection portion 98 of the liquid discharge head 2, and the shape of the heat conduction plate 294 is different from the heat conduction plate 94 of the liquid discharge head 2. Yes.

  The length of the first connection portion 96 in the first direction X is shorter than the length of the second connection portion 298 in the first direction X. For this reason, the thermal resistance per unit length of the first connection portion 96 is higher than the thermal resistance per unit length of the second connection portion 298. As a result, out of the heat generated by the control unit 92, the amount of heat transmitted through the first connection unit 96 can be reduced, and the amount of heat transmitted through the first path and the amount of heat transmitted through the second path can be made closer to each other. . Therefore, it is possible to reduce the possibility of variations in temperature distribution in the head body 2a.

  The thermal resistance per unit length of the first connection portion 96 is a thermal resistance along the first path, and can be a thermal resistance per unit length in the thickness direction Z. The same applies to the thermal resistance per unit length of the second connection portion 298.

  In the sub-scanning direction Y, the cross-sectional area of the first connection portion 96 is higher than the cross-sectional area of the second connection portion 298. As a result, out of the heat generated by the control unit 92, the amount of heat transmitted through the first connection unit 96 can be reduced, and the amount of heat transmitted through the first path and the amount of heat transmitted through the second path can be made closer to each other. . Therefore, it is possible to reduce the possibility of variations in temperature distribution in the head body 2a.

  The heat conductive plate 294 is provided so as to extend along the first direction X while maintaining a constant width in the thickness direction Z. The 1st connection part 96 and the heat conductive board 294 are connected via the 1st connection part 95a. Moreover, the 2nd connection part 298 and the heat conductive board 294 are connected via the 2nd connection part 295b. The 1st connection part 95a and the 2nd connection part 295b are connected by welding.

  The liquid ejection head 202 has a configuration in which the length of the first connection portion 96 in the first direction X is shorter than the length of the second connection portion 298 in the first direction X. The length in the first direction X is shorter than the length in the first direction X of the second connecting portion 295b.

  Therefore, the thermal resistance per unit length of the first connecting part 95a can be made higher than the thermal resistance per unit length of the second connecting part 295b. As a result, the amount of heat transmitted through the first path and the amount of heat transmitted through the second path can be made closer to each other. Therefore, it is possible to reduce the possibility of variations in temperature distribution in the head body 2a.

  FIG. 8B shows a liquid ejection head 302 which is a modified example. The liquid discharge head 302 is different from the liquid discharge head 202 in that the shape of the second connection portion 398 is different and the heat conduction plate 294 is not provided.

  As described above, the thickness of the first connection portion 96 in the sub-scanning direction Y may be smaller than the thickness of the second connection portion 398 in the sub-scanning direction Y. Even in such a case, the thermal resistance of the first connection part 96 can be made higher than the thermal resistance of the second connection part 398. Even if the heat conduction plate 294 is not provided, the amount of heat transmitted through the first path and the amount of heat transmitted through the second path can be made closer to each other.

  The liquid ejection head 402 will be described with reference to FIG. In the liquid discharge head 402, the wiring board 490 includes a ground electrode 491 inside. In FIG. 9, the ground electrode 491 is indicated by a long chain line, and in FIG. 9B, the region where the ground electrode 491 is disposed is indicated by oblique lines.

  As shown in FIG. 9C, the wiring substrate 490 includes an insulating layer 491c, a ground electrode 491 (second ground electrode 491b), a via hole 491e, and a wiring pattern 491d. The ground electrode 491 and the wiring pattern 491d are sandwiched by an insulating layer 491c, and a via hole 491e is formed in a portion where conduction is required. The wiring board 490 is formed of a hard printed wiring board or flexible FPC.

  The ground electrode 491 includes a first ground electrode 491 a disposed in the first part 490 a of the substrate 490 and a second ground electrode 491 b disposed in the second part 490 b of the substrate 490. The first ground electrode 491a and the second ground electrode 491b are electrically connected. A control unit 92 is provided on the second ground electrode 491b, and the ground pad of the control unit 92 and the second ground electrode 491b are electrically connected. Note that the controller 92 is not necessarily connected to the ground electrode 491.

  The ground electrode 491 can be formed of, for example, a metal such as Cu, Al, Au, or an alloy.

  The first ground electrode 491a has a smaller width in the thickness direction Z than the second ground electrode 491b. Then, one side of the wiring board 490 is screwed with a screw 493a at the center of the first connecting portion 96 in the thickness direction Z. Further, the other side of the wiring board 490 is screwed by screws 493 b at both ends in the thickness direction Z of the second connection portion 98. The screws 493a and 493b are provided so as to penetrate the insulating layer 491c adjacent to the ground electrode 491 so as to be electrically connected to the ground electrode 491. Therefore, the screw 493a serves as the first connecting portion 495a, and the screw 493b serves as the second connecting portion 495b.

  The first ground electrode 491a forms a first portion 490a of the wiring board 490. The second ground electrode 491b forms a second part 490b of the wiring board 490. Then, due to the difference in the width in the thickness direction Z between the first ground electrode 491a and the second ground electrode 491b, the thermal resistance per unit length of the first ground electrode 491a is reduced per unit length of the second ground electrode 491b. It is higher than the thermal resistance.

  Therefore, the thermal resistance per unit length of the first part 490a of the wiring board 490 is higher than the thermal resistance per unit length of the second part 490b of the wiring board 490. As a result, of the heat generated by the controller 92, the amount of heat transmitted through the first portion 490a of the wiring board 490 and the amount of heat transmitted through the second portion 490b of the wiring substrate 490 can be made close to each other. It is possible to reduce the possibility of variations in the temperature distribution.

  In the cross section along the sub-scanning direction Y, the cross-sectional area of the first ground electrode 491a is smaller than the cross-sectional area of the second ground electrode 491b. Therefore, the thermal resistance per unit length of the first ground electrode 491a itself can be higher than the thermal resistance per unit length of the second ground electrode 491b itself. As a result, the possibility of variations in the temperature distribution of the head main body 2a can be reduced.

In the cross section along the sub-scanning direction Y, the example in which the width in the thickness direction Z of the ground electrode 491 is changed is shown. However, the length of the ground electrode 491 in the sub-scanning direction Y is changed to change to the sub-scanning direction Y. The cross-sectional area along may be changed.

<Fourth Embodiment>
The liquid discharge head 502 will be described with reference to FIG. The liquid discharge head 502 includes two controllers 592, and the configuration of the ground electrode 591 is different from the liquid discharge head 402.

  The control unit 592 includes a first control unit 592a and a second control unit 592b. The first control unit 592a and the second control unit 592b may be components having the same function or may be components having different functions. Further, the first control unit 592a may be an analog circuit unit, and the second control unit 592b may be a digital circuit unit.

  The ground electrode 591 includes a first ground electrode 591a and a second ground electrode 591b. The first ground electrode 591a and the second ground electrode 591b are separated from each other by a separation portion 591f with a predetermined distance. The first ground electrode 591a is connected to the first connection part 96 via the first connection part 595a. The second ground electrode 591b is connected to the second connection part 98 via the second connection part 595b.

  A first control unit 592a is provided on the second ground electrode 591b, and a second control unit 592b is provided on the first ground electrode 591a. The first ground electrode 591a and the second ground electrode 591b are separated from each other by the separation portion 591f and are electrically insulated. Further, the first ground electrode 591a and the second ground electrode 591b are also thermally separated by the separation portion 591f.

  Accordingly, the liquid discharge head 502 has a configuration in which heat is transmitted to one side of the head body 2a as the first path via the second control unit 592b, the first ground electrode 591a, and the first connection unit 96. ing. Further, the liquid discharge head 502 has a configuration in which heat is transmitted to the other side of the head main body 2a through the first control unit 592a, the second ground electrode 591b, and the second connection unit 98 as the second path. Yes.

  Therefore, the heat of the second controller 592b is supplied to one side of the head body 2a via the first path, and the heat of the first controller 592a is supplied to the other side of the head body 2a via the second path. Will be. As a result, it is possible to suppress the heat of the first control unit 592a from being transmitted to the first connection unit 96. Therefore, it is possible to reduce the possibility that the first connection unit 96 transfers the heat of the first control unit 592a, and it is possible to suppress the possibility that excessive heat is supplied to the first connection unit 96.

  That is, the separation part 591f arranged between the first control part 592a and the first connection part 96 functions as a part having a high thermal resistance, so that the heat of the first control part 592a is transferred to the first connection part 96. The possibility of transmission can be reduced. Similarly, the separation part 591f disposed between the second control part 592b and the second connection part 98 functions as a part having a high thermal resistance, so that the heat of the second control part 592b is transmitted to the second connection part 98. It is possible to reduce the possibility of being transmitted to. As a result, it is possible to reduce the possibility of variations in temperature distribution in the head main body 2a.

  In addition, the distance between the first ground electrode 591a and the second ground electrode 591b in the first direction X is preferably longer than the distance between the first ground electrode 591a and the second ground electrode 591b in the thickness direction Z. As a result, the separation portion 591f functions as a high thermal resistance portion.

  Further, the first ground electrode 591a and the second ground electrode 591b are completely separated by the separation portion 591f. Therefore, the first ground electrode 591a and the second ground electrode 591b are thermally independent from each other. As a result, the heat of the second controller 592b provided on the first ground electrode 591a is less likely to affect the second ground electrode 519b, and the heat of the first controller 592a provided on the second ground electrode 591b is reduced. Heat hardly affects the first ground electrode 591a. Therefore, the heat of the second control unit 592b is hardly transmitted to the second connection unit 98, and the heat of the first control unit 592a is not easily transmitted to the first connection unit 96, resulting in variations in the temperature distribution of the head body 2a. The possibility can be reduced.

  Note that the separation portion 591f does not have to completely separate the first ground electrode 591a and the second ground electrode 591b. The first ground electrode 591a and the second ground electrode 591b may be partially connected. In this case, the connecting portion is preferably 20% or less of the region where the separating portion 591f is provided.

<Fifth Embodiment>
The liquid discharge head 602 will be described with reference to FIG. The liquid discharge head 602 differs from the liquid discharge head 502 in the shape of the ground electrode 691 and is otherwise the same.

  The ground electrode 691 includes a first ground electrode 691a and a second ground electrode 691b. The length of the first ground electrode 691a in the thickness direction Z is longer than the length of the second ground electrode 691b in the thickness direction Z. It has a short configuration.

  Therefore, the thermal resistance per unit length of the first ground electrode 691a is higher than the thermal resistance per unit length of the second ground electrode 691b. As a result, the amount of heat transmitted through the first ground electrode 691a can be reduced, and the possibility of variations in the temperature distribution of the head body 2a can be reduced.

  Further, the wiring board 690 is connected to the first connection portion 96 by screws 631a1 and 631a2, and is connected to the second connection portion 98 by screws 631b1 and 631b2. The first ground electrode 691a is connected to the first connection portion 96 only by the first coupling portion 695a2. Therefore, the possibility that heat is transferred from the first ground electrode 691a to the first connection portion 96 can be further reduced.

  As shown in FIG. 11B, the first ground electrode 791a is drawn out to a screw 693a1 provided at the upper end of the first connecting portion 96 in the thickness direction Z, and the first ground electrode 791a and the first connecting portion are drawn. 695a1 may be connected.

  In this case, the first ground electrode 791a is connected to the first connection portion 96 at the first connection portion 695a1, and the second ground electrode 791b is connected to the second connection portion 98 at the second connection portions 695b1 and 695b2. Will be connected.

  In such a case, the distance between the first connection portion 695a1 and the head body 2a is longer than the distance between the second connection portion 695b2 and the head body 2a, and the first connection portion 96 is heated in the first path. The distance to conduct can be made longer than the distance to conduct heat through the second connection part 98 in the second path. As a result, the thermal resistance of the first path can be made higher than the thermal resistance of the second path, and the possibility that variations in temperature distribution occur in the head body 2a can be further reduced. As a result, the possibility of variations in ejection characteristics in the head body 702 can be further reduced.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although the printer 1 using the liquid discharge head 2 according to the first embodiment is shown, the present invention is not limited to this, and the liquid discharge heads 102, 202, 302, 402, 502 according to other embodiments are shown. , 602, 702 may be used for the printer 1. In addition, the liquid discharge heads 2, 102, 202, 302, 402, 502, 602, and 702 that are a plurality of embodiments may be combined.

  That is, the liquid ejection heads 502, 602, and 702 may be provided with the heat conduction plate 94, and the liquid ejection heads 2, 102, 202, and 302 may be screwed using screws 493.

1 Printer (recording device)
2, 102, 202, 302, 402, 502, 602, 702 Liquid discharge head 4 Flow path member 5 Manifold 8 Discharge hole 10 Pressurizing chamber 21 Piezoelectric actuator substrate (pressurizing section)
80 Conveying part 90 Wiring board 90a 1st part 90b 2nd part 92 Control part 94 Heat conduction board 94a 1st part 94b 2nd part 96 1st connection part 98 2nd connection part

Claims (16)

A head body having a plurality of ejection holes for ejecting liquid, and a plurality of pressure units respectively connected to the plurality of ejection holes;
A substrate having a control unit that controls driving of the plurality of pressurizing units;
A first connecting portion for connecting one end of the head body and the substrate;
A second connecting portion for connecting the other end of the head body and the substrate;
Have
The distance from the control unit to the first connection unit is smaller than the distance from the control unit to the second connection unit,
The substrate has a notch at an edge of the substrate so that the width is narrow only on the first connection portion side of the portion of the region adjacent to the portion where the control unit is disposed. A liquid discharge head characterized by the above. Claim 1, wherein the heat generated by the control unit, characterized in that the conductive hard structure to the first connecting portion through a site where the incision is provided from the site where the control unit is arranged The liquid discharge head described in 1. 3. The liquid ejection head according to claim 1, wherein the portion where the cut is provided has a reduced cross-sectional area due to a decrease in width. 4. The liquid ejection head according to claim 1, wherein the portion provided with the cut is narrowed from both sides. 5.   5. The liquid ejection head according to claim 1, wherein a thermal resistance of the first connection portion is higher than a thermal resistance of the second connection portion.   The liquid ejection head according to claim 5, wherein a cross-sectional area of the first connection portion is smaller than a cross-sectional area of the second connection portion. A first connecting portion connecting the substrate and the front Symbol first connecting portion further includes a second connecting portion connecting the substrate and the second connecting portion,
7. The liquid ejection head according to claim 1, wherein a distance between the first connecting portion and the head main body is longer than a distance between the second connecting portion and the head main body.   8. The liquid ejection head according to claim 1, wherein the substrate includes a heat conductive plate that contacts the control unit, the first connection unit, and the second connection unit. 9. A plurality of ejection holes for ejecting a liquid, and a plurality of pressure units connected to the plurality of ejection holes, respectively, and a head body that is long in the first direction;
A control unit that controls driving of the plurality of pressurizing units, and a substrate that is long in the first direction;
A first connecting portion that connects one end of the head body and one end of the substrate;
A second connecting portion for connecting the other end of the head body and the other end of the substrate;
The control unit is disposed closer to the first connection unit than the center of the substrate;
The liquid discharge head according to claim 1, wherein a thermal resistance of the first connection portion is higher than a thermal resistance of the second connection portion.   The liquid discharge head according to claim 9, wherein a cross-sectional area of the first connection portion is smaller than a cross-sectional area of the second connection portion. A first connecting portion that connects the first connecting portion and the substrate; and a second connecting portion that connects the second connecting portion and the substrate;
11. The liquid ejection head according to claim 9, wherein a distance between the first connecting portion and the head main body is longer than a distance between the second connecting portion and the head main body. A plurality of ejection holes for ejecting a liquid, and a plurality of pressure units connected to the plurality of ejection holes, respectively, and a head body that is long in the first direction;
A first control unit and a second control unit that control driving of the plurality of pressurizing units, and a substrate that is long in the first direction;
A first connecting portion that connects one end of the head body and one end of the substrate;
A second connecting portion for connecting the other end of the head body and the other end of the substrate;
A first ground electrode disposed from the second control unit to the first connection unit so as to overlap the second control unit and the first connection unit; and the first control unit and the second control unit. A second ground electrode disposed from the first control unit to the second connection unit so as to overlap the connection unit,
The first ground electrode and the second ground electrode are separated by a separation unit, and a distance from the second control unit to the first connection unit is determined from the first control unit to the second connection unit. Smaller than the distance to
The liquid discharge head according to claim 1, wherein a thermal resistance per unit length of the first ground electrode is higher than a thermal resistance per unit length of the second ground electrode.   The liquid ejection head according to claim 12, wherein a cross-sectional area of the first ground electrode is smaller than a cross-sectional area of the second ground electrode.   14. The liquid ejection head according to claim 12, wherein a thermal resistance of the first connection portion is higher than a thermal resistance of the second connection portion. A first connecting part that connects the first connecting part and the first ground electrode; and a second connecting part that connects the second connecting part and the second ground electrode;
15. The liquid ejection head according to claim 12, wherein a distance between the first connecting portion and the head main body is longer than a distance between the second connecting portion and the head main body. A liquid discharge head according to any one of claims 1 to 15,
And a transport unit that transports a recording medium to the liquid discharge head.

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