JP2017132200A - Ink jet head and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head which can reduce the influence on the operation of a piezoelectric actuator board given by a flexible wiring board.SOLUTION: An ink jet head includes: a channel member 23 having a compression chamber 35; a piezoelectric actuator board 25 overlapping so as to cover the compression chamber 35; and a flexible wiring board 27 which has a base film 55, wiring 61 provided in the base film 55 and an insulation film 59 covering the wiring 61, and is electrically connected to the piezoelectric actuator board 25 by a connection part 65. In a portion of the insulation film 59 overlapping the compression chamber 35, a thick part 59d extending along a y direction and a thin part 59e extending along the y direction and whose thickness of the insulation film 59 from the base film 55 is thinner than the thick part 59d are arranged alternately in an x direction.SELECTED DRAWING: Figure 6

Description

  The present disclosure relates to an inkjet head and a printer used in an inkjet printer.

  A piezo ink jet head is known (for example, Patent Document 1). Such an inkjet head includes a flow path member in which an ink flow path is formed, a piezoelectric actuator substrate overlaid on the flow path member, and a flexible wiring board that covers a surface of the piezoelectric actuator substrate opposite to the flow path member. And have. The flow path member has a nozzle for ejecting ink, and a pressurizing chamber that communicates with the nozzle and opens on the opposite side of the nozzle opening direction. The piezoelectric actuator substrate closes the pressurizing chamber, and when a voltage is applied, the piezoelectric actuator substrate bends into the pressurizing chamber by a reverse voltage effect and applies pressure to the ink in the pressurizing chamber. As a result, ink is ejected from the nozzles. The flexible wiring board electrically mediates between the piezoelectric actuator board and a driver that drives and controls the piezoelectric actuator board.

JP 2010-105317 A

  An inkjet head according to the present disclosure includes a plurality of nozzles that are open on a first surface, and a plurality of pressurizations that are located on a second surface side that is a surface opposite to the first surface and that are respectively connected to the plurality of nozzles. A channel member having a chamber, a piezoelectric actuator substrate overlying the second surface so as to cover the plurality of pressurizing chambers, a base film, a plurality of wires provided on the base film, and a plurality of the wires A flexible wiring substrate having a covering insulating film and electrically connected to the piezoelectric actuator substrate through a plurality of connecting portions; The flexible wiring board is disposed with the insulating film side facing the piezoelectric actuator substrate. When viewed in a plan view, a plurality of connection portions arranged side by side along the first direction on the piezoelectric actuator substrate are connected in a second direction, which is a direction intersecting the first direction. Several are arranged side by side. When viewed in a plan view, the pressurizing chamber is disposed between the connection portion rows. When viewed in a plan view, a portion of the insulating film that overlaps the pressurizing chamber extends along the first direction and a thick portion that extends along the first direction. Thin portions having a thickness from the base film thinner than the thick portions are alternately arranged in the second direction.

  The printer according to the present disclosure includes the inkjet head, a scanning unit that relatively moves the medium and the inkjet head, and a control unit that controls the inkjet head.

FIG. 3 is a perspective view schematically illustrating a main part of a printer according to an embodiment of the present disclosure. FIG. 2 is an exploded perspective view schematically showing a part of an inkjet head of the printer of FIG. 1. 3A is a plan view in the region IIIa of FIG. 2, and FIG. 3B is a cross-sectional view taken along the line IIIb-IIIb of FIG. FIG. 4 is an enlarged view near a region IV in FIG. 2. The top view which shows the wiring of the flexible wiring board of the inkjet head of FIG. 6A is a cross-sectional view taken along line VI-VI in FIG. 5, and FIG. 6B is an enlarged view of a region VIb in FIG. 6A. Sectional drawing corresponded to Fig.6 (a) which shows the modification of a flexible wiring board. FIG. 8A and FIG. 8B are plan views showing modifications of the conductor pattern of the flexible wiring board.

  When the flexible wiring substrate covers the piezoelectric actuator substrate, the piezoelectric actuator substrate may affect the bending deformation due to the inverse piezoelectric effect. For example, when the flexible wiring substrate is in contact with the piezoelectric actuator substrate on the pressurizing chamber, the load of the flexible wiring substrate is applied to the pressurizing chamber side with respect to the piezoelectric actuator substrate. As a result, the intended operation may not be realized accurately. Therefore, it is desirable to provide an ink jet head that can reduce the influence of the flexible wiring board on the operation of the piezoelectric actuator substrate.

  FIG. 1 is a perspective view schematically illustrating a main part of a printer 1 according to an embodiment of the present disclosure.

  The printer 1 is an ink jet printer. More specifically, for example, the printer 1 is a piezo head type, serial head type, and off-carriage type color printer. The printer 1 may realize a color image with an appropriate number of inks, but in this embodiment, the printer 1 realizes a color image with four colors (black, yellow, magenta, and cyan).

  The printer 1 includes, for example, a transport unit 3 that transports a medium (for example, paper) 101 in a transport direction indicated by an arrow y 1, a head 5 that ejects ink droplets toward the transported medium 101, and the head 5 as a medium 101. Controls the operation of the printer 1 including the scanning unit 7 that reciprocates in the sub-scanning direction (arrow y2) perpendicular to the conveyance direction, the ink cartridge 9 that supplies ink to the head 5, and the ink ejection operation from the head 5. And a control unit 11 that performs.

  In addition, the ejection of ink droplets from the head 5 to the medium 101 is repeatedly performed in a range extending in the main scanning direction, which is a direction orthogonal to the sub-scanning direction, and the head 5 is reciprocated by the scanning unit 7. A belt-like two-dimensional image is formed on the medium 101. Further, the medium 101 is intermittently conveyed by the conveyance unit 3, so that a continuous two-dimensional image is formed on the medium 101 by connecting the band-shaped two-dimensional images.

  For example, the transport unit 3 transports a plurality of media 101 stacked on a supply stack (not shown) one by one to a discharge stack (not shown). The transport unit 3 may have a known appropriate configuration. In FIG. 1, the conveyance path 3 is illustrated as a straight path, and includes a conveyance unit 3 having a roller 13 that contacts the medium 101, a motor 15 that rotates the roller 13, and a driver 17 that applies drive power to the motor 15. Yes.

  The scanning unit 7 may have a known appropriate configuration. For example, the scanning unit 7 includes a guide rail (not shown) that supports a carriage (not shown) on which the head 5 is mounted so that it can be guided in the sub-scanning direction, a belt (not shown) fixed to the carriage, and the belt spans. And a motor 19 that rotates the pulley, and a driver 21 that applies driving power to the motor 19.

  The ink cartridge 9 is installed at a location different from the head 5 (so as not to move with the head 5). The ink cartridge 9 is connected to the head 5 via a flexible tube. A plurality (four in this embodiment) of ink cartridges 9 are provided corresponding to the number of ink colors ejected by the head 5.

  The control unit 11 includes, for example, a CPU, a ROM, a RAM, and an external storage device. The control unit 11 outputs control signals to the driver 17 of the transport unit 3, the driver 21 of the scanning unit 7, and the driver (described later) of the head 5, and controls the operations of the transport unit 3, the scanning unit 7, and the head 5.

  FIG. 2 is an exploded perspective view showing a part of the head 5. Note that the lower side of the sheet of FIG. 2 (the negative side in the z direction) is the medium 101 side.

  The head 5 includes a flow path member 23 constituting an ink flow path, a piezoelectric actuator substrate 25 that generates a driving force for ejecting ink from the flow path member 23, and an FPC electrically connected to the piezoelectric actuator substrate 25. (Flexible wiring board) 27 and a driver IC 29 for driving and controlling the piezoelectric actuator substrate 25 via the FPC 27.

  The flow path member 23 is formed, for example, roughly in a thin rectangular parallelepiped shape, and has a first surface 23 a facing the medium 101 and a second surface 23 b on the back surface thereof. A plurality of nozzles described later are opened on the first surface 23a in order to eject ink droplets. In addition, an ink supply port 31 through which ink is supplied is formed at each end of the second surface 23b for each color.

  The piezoelectric actuator substrate 25 is formed, for example, roughly in a thin rectangular parallelepiped shape, and is superimposed on the second surface 23 b of the flow path member 23. The piezoelectric actuator substrate 25 is formed, for example, in a size that covers most of the second surface 23b (a portion excluding the arrangement region of the plurality of ink supply ports 31).

  The FPC 27 has, for example, a facing portion 27 a that covers the piezoelectric actuator substrate 25, and an extending portion 27 b that extends from the portion to the outside of the piezoelectric actuator substrate 25. The extending portion 27b may be provided in any direction of the main scanning direction and the sub-scanning direction.

  The driver IC 29 is mounted, for example, on the same surface as the surface of the extending portion 27 b where the facing portion 27 a faces the piezoelectric actuator substrate 25. The driver IC 29 may be arranged at an appropriate position by bending the FPC 27. Further, two extending portions may be provided in the FPC 27, and driver ICs 29 (two driver ICs 29 in total) may be provided in each of the two extending portions.

3A is an enlarged plan view showing the flow path member 23 and the piezoelectric actuator substrate 25 in a region corresponding to the region IIIa in FIG. 2, and FIG. 3B is a IIIb-IIIb line in FIG. 3A. FIG.

  As already described, the flow path member 23 has a plurality of nozzles 33 that open to the first surface 23a. Further, the flow path member 23 communicates with the plurality of nozzles 33 and opens to the second surface 23b side, and a plurality of pressurizing chambers 35 (see also FIG. 2), and the ink from the ink supply port 31 has a plurality of pressurizing chambers. 35 and a common flow path 37 (FIG. 3B) for supplying to 35.

  Note that these specific shapes may be set as appropriate. For example, as shown in the present embodiment, the planar shape of the pressurizing chamber 35 may be a substantially rectangular shape in which the nozzle 33 is connected to the center of the short side. Further, for example, the planar shape of the pressurizing chamber 35 may be a rhombus in which the nozzle 33 is connected to a corner, or an ellipse or an ellipse in which the nozzle 33 is connected to a semicircular end. May be.

  The flow path member 23 is configured, for example, by laminating a plurality of plate-like members 39 formed with through holes or grooves serving as flow paths in the z direction. The plurality of plate-like members 39 are made of metal, for example. The plate-like member 39 constituting the first surface 23a may be made of resin, and the other plate-like member 39 may be made of metal.

  The piezoelectric actuator substrate 25 is constituted by, for example, a unimorph type piezoelectric actuator substrate, and in order from the flow path member 23 side, an elastic body 41, a common electrode 43, a piezoelectric body 45, and a plurality of individual electrodes 47 (see also FIG. 2). ) Are stacked. In addition, these are all formed in layered form (plate shape).

  The elastic body 41 constitutes the upper surface of the plurality of pressurizing chambers 35. When a voltage is applied between the individual electrode 47 and the common electrode 43, the piezoelectric body 45 contracts in the plane direction due to the inverse piezoelectric effect. Thereby, the elastic body 41 bends to the pressurizing chamber 35 side. Using this operation, pressure is applied to the ink in the pressurizing chamber 35 and ink droplets are ejected from the nozzle 33.

  The elastic body 41, the common electrode 43 and the piezoelectric body 45 are provided over the plurality of pressurizing chambers 35. On the other hand, the individual electrode 47 is provided for each pressurizing chamber 35. For example, a reference potential is applied to the common electrode 43. A potential (drive signal) different from that of the common electrode 43 is selectively applied to the plurality of individual electrodes 47. Thereby, ink droplets are selectively ejected from the plurality of nozzles 33.

  The plurality of individual electrodes 47 overlaps the entire pressurizing chamber 35 and includes an electrode body 47 a for applying a voltage to the piezoelectric body 45 and an extraction electrode 47 b for connection to the FPC 27. For example, the electrode body 47 a has a shape substantially similar to (similar to) the planar shape of the pressurizing chamber 35, and is rectangular and smaller than the pressurizing chamber 35 in the present embodiment. The extraction electrode 47b extends from the electrode body 47a in an appropriate direction. For example, the extraction electrode 47b extends to the opposite side of the nozzle body 33 from the electrode body 47a to a position where it does not overlap the pressurizing chamber 35. When the piezoelectric body 45 sandwiched between the individual electrode 47 and the common electrode 43 is contracted in the plane direction and the elastic body 41 bends toward the pressurizing chamber 35, the piezoelectric body 45 at the peripheral portion of the pressurizing chamber 35. Will be stretched in the planar direction. Therefore, when the piezoelectric body 45 at the peripheral edge of the pressurizing chamber 35 is reduced in the planar direction by the inverse piezoelectric effect, the amount of bending is rather reduced. Therefore, no electrode other than the extraction electrode 47b that transmits the drive signal is provided on the peripheral edge of the pressurizing chamber 35.

  In the following, the portion corresponding to one nozzle 33 (outline, arrangement region of the pressurizing chamber 35 and the individual electrode 47 in plan view) of the flow path member 23 and the piezoelectric actuator substrate 25 shown in FIG. Sometimes referred to as an ejection element 49.

  FIG. 4 is a plan view showing the flow path member 23 and the piezoelectric actuator substrate 25 in a region substantially corresponding to the region IV in FIG.

  As shown in FIGS. 2 and 4, the plurality of ejection elements 49 constitute ejection element rows 51 arranged in a first direction substantially coincident with the main scanning direction. A plurality of ejection element rows 51 exist and are arranged in the second direction, which is a direction intersecting the first direction. The second direction and the sub-scanning direction substantially coincide. Specifically, for example, it is as follows.

  In each of the plurality of ejection elements 49, the direction in which the nozzle 33 is disposed with respect to the pressurizing chamber 35 or the extraction electrode 47b extends with respect to the electrode body 47a is the sub-scanning direction (x direction, second direction). It is arranged to match.

In the row of ejection elements 49 (ejection element row 51) configured by arranging a plurality of ejection elements 49 in the main scanning direction (y direction, first direction), the plurality of ejection elements 49 have the same orientation. Has been. Adjacent ejection element rows 51 are arranged so that the nozzles 33 (extraction electrodes 47b) are opposite to each other and are half the size of the ejection elements 49 in the main scanning direction and are shifted from each other. .

  The two ejection element rows 51 facing each other on the nozzle 33 side correspond to one ink, and in the present embodiment, a total of eight ejection element rows 51 are provided corresponding to the four colors. . For black ink, the number of ejection element rows 51 may be different for each color, such as increasing the number of ejection element rows 51.

  As is clear from the fact that the plurality of ejection elements 49 constitutes the plurality of ejection element rows 51, the plurality of pressurizing chambers 35 are arranged in the main scanning direction (y direction, first direction). A pressure chamber row 53 (FIG. 2) is configured, and a plurality of pressure chamber rows 53 are arranged in the sub-scanning direction (x direction, second direction).

  As shown in FIG. 4, the common flow path 37 is connected to the ink supply port 31, branches according to the number of ejection element rows 51, and extends along the ejection element rows 51.

  FIG. 5 is a plan view illustrating a wiring pattern of the FPC 27 with respect to a region having the same size as the region illustrated in FIG. 4. FIG. 6A is a cross-sectional view of the uppermost plate-like member 39, the piezoelectric actuator substrate 25, and the FPC 27 of the flow path member 23 taken along the line VIa-VIa of FIG.

  As shown in FIG. 6A, the FPC 27 includes an insulating base film 55, a conductor pattern 57 formed on the base film 55, and an insulating film 59 that covers the conductor pattern 57. The facing portion 27a of the FPC 27 is disposed with the insulating film 59 side facing the piezoelectric actuator substrate 25 side.

  The base film 55 is made of, for example, a flexible resin film. The conductor pattern 57 is made of metal, for example. The insulating film 59 is made of, for example, a solder resist. The solder resist is made of, for example, a thermosetting epoxy resin containing a pigment or the like.

  As shown in FIGS. 5 and 6A, the conductor pattern 57 includes a plurality of wirings 61 and a plurality of pads 63 provided at the tips of the plurality of wirings 61.

  For example, the plurality of wirings 61 extend in parallel (for example, in parallel) with each other along the ejection element row 51 so as to overlap the ejection element row 51 (pressure chamber row 53). However, the plurality of wirings 61 (bundles or arrangement regions thereof) extend at positions shifted to the opposite side to the extraction electrode 47 b side with respect to the ejection element row 51. For example, the plurality of wirings 61 do not overlap the extraction electrode 47b side of the pressurization chamber 35, but overlap the opposite side of the pressurization chamber 35 from the extraction electrode 47b. From another point of view, the plurality of wirings 61 extend in an overlapping manner between the two ejection element rows 51 facing the opposite side to the extraction electrode 47b side.

  In FIG. 5, the plurality of wirings 61 are, for example, the side where the upper side (the negative side in the y direction) is connected to the driver IC 29. As shown in FIG. 5, the plurality of wirings 61 are bent in order from the first part extending along the ejection element row 51 from the driver IC 29 side and the wiring 61 located outside that is the first part, and the extraction electrode 47b. And a second portion provided with a pad 63 at the tip thereof.

The pad 63 and the extraction electrode 47b face each other and are joined by a bump 65 (FIG. 6A) which is a connection portion. As a result, the driver IC 29 is electrically connected to the individual electrode 47 via the wiring 61. Further, the FPC 27 is fixed to the piezoelectric actuator substrate 25. The bump 65 may be formed of an appropriate material having conductivity. For example, the bump 65 is made of a resin (for example, thermosetting resin) including particles made of metal (for example, Ag).

  As shown in FIGS. 5 and 6A, the insulating film 59 covers the plurality of wirings 61 with the pads 63 exposed. Thereby, the short circuit between the plurality of wirings 61 due to the adhesion of the conductive material is reduced. In FIG. 5, a range AR indicates the width of the insulating film 59. The insulating film 59 has a width that overlaps at least a part of the pressurizing chamber 35.

  As shown in FIG. 6A, the bumps 65 are interposed between the extraction electrodes 47b and the pads 63, so that the individual electrodes 47 and the insulating film 59 are in contact with each other at a relatively low pressure. Alternatively, they face each other with a minute gap (for example, 10 μm or less).

  Such a state is realized, for example, by bonding the FPC 27 to the piezoelectric actuator substrate 25 as follows. First, an uncured material to be the bump 65 is applied on the extraction electrode 47b. Next, the FPC 27 is placed on the piezoelectric actuator substrate 25, and the FPC 27 is pressed against the piezoelectric actuator substrate 25. At this time, the material to be the bump 65 is crushed (deformed), and the insulating film 59 contacts or approaches the piezoelectric actuator substrate 25. Thereafter, the material to be the bump 65 is heat-cured.

  FIG. 6B is an enlarged view of a region VIb in FIG.

  As shown in FIGS. 6A and 6B, the thickness T of the insulating film 59 from the base film 55 is thinner on the end side than the plurality of wirings 61 side. That is, the insulating film 59 has a thick region 59a and a thin region 59b. Further, this change in thickness occurs on the pressurizing chamber 35. That is, on the pressurizing chamber 35, the thickness T is thinner on the opposite side than the plurality of wirings 61 side. In other words, the thickness T is a height from the base film 55 to the surface of the insulating film 59.

  As shown in FIGS. 6A and 6B, the thickness T2 of the insulating film 59 from the base film 55 is thin at a plurality of portions in the thick region 59a. This thin region extends between the wirings 61 along the y direction, which is the direction in which the wirings 61 extend. In other words, the insulating film 59 in the portion overlapping the pressurizing chamber 35 has a thick portion 59d extending along the y direction and a thickness portion extending along the y direction and having a thickness larger than that of the thick portion 59d. Thin thin portions 59e are alternately arranged in the x direction. The portions where the thick portions 59d and the thin portions 59e are alternately arranged may be extended to a region where the wiring 61 is not arranged.

  Such a change in the thickness of the insulating film 59 can be appropriately generated. For example, although depending on the formation method of the insulating film 59, the arrangement region of the plurality of wirings 61 tends to be thicker than the non-arrangement region. For example, when a solder resist is applied by screen printing to form the insulating film 59, the insulating film 59 becomes thicker in the arrangement region of the plurality of wirings 61 and becomes thinner at the end portion which is a non-arrangement region.

  Note that instead of or in addition to this method, for example, a material such as a solder resist may be applied to the entire region where the insulating film 59 is formed, and then the material may be applied again only to the region where the thickness T is desired to be increased. In addition, after applying a solder resist to be the insulating film 59, before drying or curing, or in a semi-dried or semi-cured state, a portion where the thickness T is desired to be reduced is pressed with a mold or the like, and deformed. A thick portion and a thin portion may be formed in the insulating film 59.

  The driver IC 29 shown in FIG. 2 is electrically connected to the plurality of individual electrodes 47 via the FPC 27 as described. Although not particularly illustrated, the piezoelectric actuator substrate 25 is provided with a pad connected to the common electrode 43, and the wiring of the FPC 27 and the pad are joined to the pad, so that the driver IC 29 is electrically connected to the common electrode 43. Connected.

  For example, data on the amount of ink to be ejected for all the nozzles 33 is input from the control unit 11 to the driver IC 29 at every predetermined driving cycle. For example, the driver IC 29 applies a reference potential to the common electrode 43 and selectively outputs a drive signal having a predetermined waveform to the plurality of individual electrodes 47 based on the input data. Further, the driver IC 29 sets the number of times that the drive signal is output within the drive cycle based on the input data, for example.

  As described above, in the present embodiment, the head 5 includes the flow path member 23, the piezoelectric actuator substrate 25, and the FPC 27. The flow path member 23 has a nozzle 33 that opens to the first surface 23a, and a pressurizing chamber 35 that communicates with the nozzle 33 and opens to the second surface 23b that is the back surface of the first surface 23a. As the flow path member 23, a member in which a plate member 39 is further laminated on the side where the pressurizing chamber 35 is opened so as to close the pressurizing chamber 35 may be used. By disposing the pressurizing chamber 35 on the second surface 23 b side in the flow path member 23, the pressure generated in the piezoelectric actuator substrate 25 disposed so as to cover the pressurizing chamber 35 is laminated on the pressurizing chamber 35. The pressure is transmitted to the pressurizing chamber 35 via the plate-shaped member 39 thus formed. By doing so, for example, the possibility that an ink solvent or the like affects the reliability of the piezoelectric actuator substrate 25 can be reduced. The piezoelectric actuator substrate 25 is stacked on the second surface 23b to close the pressurizing chamber 35. The FPC 27 has an insulating base film 55, a wiring 61 provided on one surface of the base film 55, and an insulating film 59 covering the wiring 61, and the insulating film 59 side is a flow path member of the piezoelectric actuator substrate 25. The piezoelectric actuator substrate 25 is electrically connected to the piezoelectric actuator substrate 25. On the pressurizing chamber 35, the thickness T of the insulating film 59 from the base film 55 is on one side (wiring 61 side) and the other side in a predetermined direction (x direction, second direction) along the second surface 23b. Is different.

  Therefore, on the pressurizing chamber 35, the insulating film 59 is suppressed from contacting the piezoelectric actuator substrate 25 (individual electrode 47) with the thin portion serving as a spacer. As a result, the influence of the FPC 27 on the operation of the piezoelectric actuator substrate 25 can be reduced. Specifically, for example, it is suppressed that the load of the FPC 27 is applied to the piezoelectric actuator substrate 25 on the pressurizing chamber 35. In addition, for example, since the FPC 27 is prevented from coming into close contact with the individual electrode 47 in at least a part on the pressurizing chamber 35, when the individual electrode 47 is separated from the FPC 27, air easily enters between the two. The resistance due to the negative pressure is reduced.

  Since the thick portion 59d and the thin portion 59e are arranged in the thick region 59a at a position overlapping the pressurizing chamber 35, the influence on the operation of the piezoelectric actuator substrate 25 can be reduced. Further, the flexible wiring board 27 and the piezoelectric actuator board 25 are electrically and physically joined by bumps 65 which are connecting portions. The plurality of connecting portions (bumps 65) are arranged side by side in the y direction to form a connecting portion row 66. The plurality of connection portion rows 66 are arranged in the x direction. That is, the flexible wiring board 27 is easily bent in the x direction in which the interval between the connection portions (bumps 65) is larger than the y direction. Therefore, by arranging the thick portions 59d extending in the y direction and the thin portions 59e extending in the y direction alternately in the x direction, the flexible wiring board 27 can be more easily bent in the x direction, thereby providing a piezoelectric actuator. The influence on the operation of the substrate 25 can be further reduced.

  Further, by arranging the thin part 59e between the adjacent wirings 61, the wiring 61 is arranged in the thick part 59d, so that the wiring 61 is exposed and the disconnection or the like is suppressed. it can.

  In the present embodiment, the plurality of wirings 61 are positioned on one side on the pressurizing chamber 35, and the thickness T of the insulating film 59 from the base film 55 is such that the one side (the plurality of wirings 61 side) is the other side. It is thicker than the side.

  Therefore, depending on the method of forming the insulating film 59, the thickness T is simply set on the one side and the other side on the pressurizing chamber 35 by utilizing the phenomenon that the thickness T tends to increase in the arrangement region of the plurality of wirings 61. And can be different.

  In the present embodiment, the extraction electrode 47 b is extracted from the pressurizing chamber 35 on the side where the thickness T of the insulating film 59 from the base film 55 is reduced. The portion where the extraction electrode 47b exists is a portion having a large vibration caused by the addition of a drive signal in the peripheral portion of the pressurizing chamber 35, and is a portion that is greatly affected by the proximity of the insulating film 59. This influence can be made difficult to occur because the thickness T of the insulating film 59 on the side from which the extraction electrode 47b is extracted is thin.

  FIG. 7 is a cross-sectional view corresponding to FIG. 6A showing a modification of the FPC 27.

  In this modification, the insulating film 59 has a thickness T (see FIG. 6B) from the base film 55 located on the pressurizing chamber 35 between the pressurizing chamber rows 53 (see FIG. 2). The portion (second thick region 59c) is thicker than the portion (thick region 59a and thin region 59b). For example, the second thick region 59 c extends along the pressurizing chamber row 53 and has a length extending over the plurality of pressurizing chambers 35 in each pressurizing chamber row 53.

  The second thick region 59c may be formed by the same method as the thick region 59a is formed with respect to the thin region 59b. For example, in the second thick region 59 c, the density of the wiring 61 is made higher than that in the thick region 59 a, and the material that forms the insulating film 59 between the pressurizing chamber rows 53 is made higher than that on the pressurizing chamber 35. It may be formed by applying a large number of times.

  According to such a configuration, the insulating film 59 is further prevented from contacting the piezoelectric actuator substrate 25 (individual electrode 47) on the pressurizing chamber 35, and the influence of the FPC 27 on the operation of the piezoelectric actuator substrate 25 is further reduced. it can.

  In this modification, the end of the insulating film 59 is located on the pressurizing chamber 35. Accordingly, the insulating film 59 does not contact the piezoelectric actuator substrate 25 outside the end of the insulating film 59 in the region on the pressurizing chamber 35. From another viewpoint, the insulating film 59 serves as a spacer, so that the FPC 27 (base film 55) is prevented from coming into contact with the piezoelectric actuator substrate 25 in a partial region on the pressurizing chamber 35. As a result, the influence of the FPC 27 on the operation of the piezoelectric actuator substrate 25 can be further reduced.

  FIG. 8A and FIG. 8B are plan views showing modifications of the conductor pattern 57 of the FPC 27.

In the embodiment, as described with reference to FIG. 5, the plurality of wirings 61 bend outward in order from the outer wiring and extend onto the extraction electrode 47 b. As a result, the width of the arrangement area of the plurality of wirings 61 gradually decreased. In the modification of FIGS. 8A and 8B, the conductor pattern 57 is formed so that the width of the arrangement area of the plurality of wirings is kept constant over the plurality of pressurizing chambers 35.

  In the example of FIG. 8A, as the plurality of wirings 61 extend from the driver IC 29 side along the pressurizing chamber row 53, the plurality of wirings 61 are gradually shifted to the outside, and inside the plurality of wirings 61. The number of dummy wirings 67 extending in parallel with the plurality of wirings 61 is gradually increased. The dummy wiring 67 may be in an electrically floating state or may be connected to a reference potential.

  In the example of FIG. 8B, the plurality of wirings 61 gradually increase the width of the remaining wiring 61 as the plurality of wirings 61 extend along the pressurizing chamber row 53 from the driver IC 29 side. In FIG. 8B, the entire width of the remaining wiring 61 is gradually increased, but the width of the specific wiring 61 may be increased.

  As already described, depending on the method of forming the insulating film 59, the thickness of the insulating film 59 from the base film 55 becomes thicker in the arrangement region of the plurality of wirings 61. Therefore, as shown in FIGS. 8A and 8B, the insulating film 59 is maintained by keeping the width of the arrangement region of the plurality of wirings 61 (and the dummy wirings 67) constant over the plurality of pressurizing chambers 35. The width of the thick portion (thick region 59a) can be made constant for the plurality of pressurizing chambers 35. As a result, the influence of the FPC 27 on the plurality of pressurizing chambers 35 can be made uniform.

  Here, the constant width of the wiring arrangement region means that the change in the width of the wiring arrangement region is small as compared with the embodiment described with reference to FIG. Therefore, for example, if the change in the width of the plurality of wiring arrangement regions across the plurality of pressurizing chambers 35 is smaller than the width of one wiring 61, the width of the plurality of wiring arrangement regions is equal to the plurality of pressurizing chambers. Over 35. When the width of one wiring 61 changes as shown in FIG. 8B, for example, the determination may be made based on the minimum value of the width of one wiring 61. The local change in the arrangement area at the position where the wiring 61 branches may be ignored. The width of the wiring arrangement region is preferably within a range of ± 20%, and more preferably within a range of ± 10%, excluding the above-described local change.

  This indication is not limited to the above embodiment or modification, and may be carried out in various modes.

  For example, the printer (inkjet head) is not limited to a serial head type and an off-carriage type. For example, the printer may be a line head type and / or an on-carriage type. The configuration of a portion other than the inkjet head in the printer (for example, a media transport unit) may be an appropriate configuration other than the illustrated configuration. The medium is not limited to paper, and may be made of metal or resin.

DESCRIPTION OF SYMBOLS 5 ... Head 23 ... Flow path member 23a ... 1st surface 23b ... 2nd surface 33 ... Nozzle 35 ... Pressurization chamber 25 ... Piezoelectric actuator substrate 27 ... FPC (Flexible wiring board)
55 ... Base film 59 ... Insulating film 59a ... Thick film region 59b ... Thin wall region 59c ... Second thick film region 59d ... Thick film portion 59e ... Thin wall portion 61 ...・ Wiring 65 ... Bump (connection part)
66 ... Connection section line

Claims (4)

A plurality of nozzles opening in the first surface, and a flow path member having a plurality of pressurizing chambers that are respectively connected to the plurality of nozzles and located on the second surface side opposite to the first surface. ,
A piezoelectric actuator substrate overlying the second surface so as to cover the plurality of pressurizing chambers;
A flexible wiring board having a base film, a plurality of wirings provided on the base film, and an insulating film covering the plurality of wirings, and electrically connected to the piezoelectric actuator substrate at a plurality of connecting portions; ,
Have
The flexible wiring board is disposed with the insulating film side facing the piezoelectric actuator substrate,
When viewed in plan
On the piezoelectric actuator substrate, a plurality of connection portion rows in which a plurality of the connection portions are arranged along the first direction are arranged side by side in a second direction that intersects the first direction. And
The pressurizing chamber is disposed between the connection portion rows,
A portion of the insulating film overlapping the pressurizing chamber, a thick portion extending along the first direction, and extending along the first direction, from the base film of the insulating film An inkjet head characterized in that thin-walled portions whose thickness is thinner than the thick-walled portion are alternately arranged in the second direction.   The plurality of wirings extend along the first direction between the connection portion rows, and the thin portion is disposed between the adjacent wirings. 2. An ink jet head according to 1. Between the connection part rows, a plurality of the pressurizing chambers are arranged in the first direction, and at least two or more pressurizing chamber rows are provided,
The inkjet head according to claim 1, wherein the insulating film has a thicker portion between adjacent pressurizing chamber rows than a portion overlapping the pressurizing chamber.   A printer comprising: the inkjet head according to claim 1; a scanning unit that relatively moves a medium and the inkjet head; and a control unit that controls the inkjet head. .

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