JP6640582B2 - Inkjet head and printer - Google Patents

Description

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

  A piezo-type inkjet head is known (for example, Patent Document 1). Such an ink jet head includes a flow path member in which a flow path of ink 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 The flow path member has a nozzle for discharging ink, and a pressurizing chamber communicating with the nozzle and opening on the side opposite to the opening direction of the nozzle. The piezoelectric actuator substrate closes the pressurizing chamber, and when a voltage is applied, the piezoelectric actuator substrate bends into the pressurizing chamber due to a reverse voltage effect, and applies pressure to the ink in the pressurizing chamber. Thus, ink is ejected from the nozzle. The flexible wiring board electrically mediates between the piezoelectric actuator substrate and a driver that drives and controls the piezoelectric actuator substrate.

JP 2010-105317 A

  An inkjet head according to an embodiment of the present disclosure includes a plurality of nozzles that open on a first surface, and a pressurizing chamber that is located on a second surface side opposite to the first surface and is connected to the plurality of nozzles. A flow path member, a piezoelectric actuator substrate overlapping the second surface so as to cover the plurality of pressurizing chambers, a base film, a plurality of wirings provided on the base film, and a part of the plurality of wirings And a flexible wiring board electrically connected to the piezoelectric actuator substrate. The flexible wiring board is arranged with the insulating film side facing the piezoelectric actuator substrate. The wiring has an exposed portion that is not covered with the insulating film and a covered portion that is covered with the insulating film. The insulating film has a recess in which an outer edge of the insulating film on the wiring is recessed in a planar shape with respect to an outer edge of the insulating film on a surrounding base film.

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

FIG. 1 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 illustrating a part of the inkjet head of the printer in FIG. 1. 3A is a plan view in a region IIIa in FIG. 2, and FIG. 3B is a cross-sectional view along a line IIIb-IIIb in FIG. 3A. FIG. 4 is an enlarged view near a region IV in FIG. 2. FIG. 3A is a plan view illustrating wiring of a flexible wiring board of the inkjet head of FIG. 2, and FIG. 3B is a plan view of a pattern of an insulating film in the same place. 6A is a cross-sectional view taken along the line VI-VI of FIG. 5, and FIG. 6B is an enlarged view of a region VIb of FIG. FIG. 7 is a cross-sectional view illustrating a modification of the flexible wiring board and corresponding to FIG. FIGS. 8A and 8B are plan views showing modified examples of the conductor pattern of the flexible wiring board.

  When the flexible wiring board covers the piezoelectric actuator substrate, there is a possibility that the flexible actuator substrate may affect the bending deformation due to the inverse piezoelectric effect in the piezoelectric actuator substrate. 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 piezoelectric actuator substrate toward the pressing chamber. As a result, the intended operation may not be accurately realized. Therefore, it is desirable to provide an inkjet head that can reduce the influence of the flexible wiring substrate 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. Note that the printer 1 may realize a color image using an appropriate number of color inks. In the present embodiment, the printer 1 realizes a color image using four color (black, yellow, magenta, and cyan) inks.

  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 y1, a head 5 that discharges ink droplets toward the transported medium 101, and The scanning unit 7 reciprocates in the sub-scanning direction (arrow y2) orthogonal to the transport direction of the printer, the ink cartridge 9 for supplying ink to the head 5, and the operation of the printer 1 including the operation of discharging ink from the head 5. And a control unit 11 that performs the control.

  In addition, the reciprocating movement of the head 5 by the scanning unit 7 is performed while the ejection of the ink droplets from the head 5 to the medium 101 is repeatedly performed in a range spread in the main scanning direction which is a direction orthogonal to the sub-scanning direction. On the medium 101, a band-shaped two-dimensional image is formed. 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 belt-shaped two-dimensional images.

  The transport unit 3 transports, for example, 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 transport path is a straight path, and the transport unit 3 includes a roller 13 that contacts the medium 101, a motor 15 that rotates the roller 13, and a driver 17 that applies driving power to the motor 15. I have.

  The scanning unit 7 may have a known appropriate configuration. For example, the scanning unit 7 includes a guide rail (not shown) for supporting a carriage (not shown) on which the head 5 is mounted in the sub-scanning direction, a belt (not shown) fixed to the carriage, and a belt Pulley (not shown), a motor 19 for rotating the pulley, and a driver 21 for applying driving power to the motor 19.

  The ink cartridge 9 is installed at a location different from the head 5 (to prevent it from moving together with the head 5). The ink cartridge 9 is connected to the head 5 via a flexible tube. A plurality (four in the present 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. The lower side of the paper of FIG. 2 (negative side in the z direction) is the medium 101 side.

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

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

  The piezoelectric actuator substrate 25 is, for example, formed in a substantially thin rectangular parallelepiped shape, and is overlaid 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 a region where the plurality of ink supply ports 31 are arranged).

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

  The driver IC 29 is mounted on, for example, the same surface of the extension portion 27 b as the surface on which 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 the 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 line IIIb-IIIb in FIG. FIG.

  As described above, the flow path member 23 has a plurality of nozzles 33 that open on the first surface 23a. The flow path member 23 communicates with the plurality of nozzles 33 and opens a plurality of pressurizing chambers 35 (see also FIG. 2) on the second surface 23b side. And a common flow channel 37 (FIG. 3B) for supplying the air to the power supply 35.

  In addition, these specific shapes may be appropriately set. For example, as shown in the present embodiment, the planar shape of the pressure 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 pressure 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. You may.

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

  The piezoelectric actuator substrate 25 is formed of, for example, a unimorph-type piezoelectric actuator substrate, and sequentially includes an elastic body 41, a common electrode 43, a piezoelectric body 45, and a plurality of individual electrodes 47 (see also FIG. 2) from the flow path member 23 side. ) Are stacked. These are all formed in layers (plates).

  The elastic body 41 forms the upper surface of the plurality of pressure 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 toward the pressure chamber 35 side. By utilizing this operation, a pressure is applied to the ink in the pressure chamber 35, and the ink droplet is ejected from the nozzle 33.

  The elastic body 41, the common electrode 43, and the piezoelectric body 45 are provided over the entire plurality of pressure chambers 35. On the other hand, the individual electrodes 47 are 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. Thus, ink droplets are selectively ejected from the plurality of nozzles 33.

  The plurality of individual electrodes 47 substantially overlap the entire pressure chamber 35, and have an electrode body 47a for applying a voltage to the piezoelectric body 45 and an extraction electrode 47b for connection to the FPC 27. The electrode main body 47a has, for example, a shape substantially similar to (similar to) the planar shape of the pressurizing chamber 35. In the present embodiment, the electrode main body 47a is rectangular and smaller than the pressurizing chamber 35. The extraction electrode 47b extends in an appropriate direction from the electrode main body 47a. For example, the extraction electrode 47b extends to the side opposite to the nozzle 33 with respect to the electrode main body 47a to a position that does not overlap with the pressure chamber 35. When the elastic body 41 bends toward the pressurizing chamber 35 due to the piezoelectric body 45 sandwiched between the individual electrode 47 and the common electrode 43 contracting in the plane direction, the piezoelectric body 45 on the periphery of the pressurizing chamber 35 Will be elongated in the plane 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 reduced. Therefore, no electrodes other than the extraction electrode 47b for transmitting the drive signal are provided on the peripheral portion of the pressurizing chamber 35.

  In the following, a portion corresponding to one nozzle 33 (arranged region of the pressurizing chamber 35 and the individual electrode 47 in a plan view) of the flow path member 23 and the piezoelectric actuator substrate 25 shown in FIG. It may be referred to as the 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 that are arranged in a first direction substantially coincident with the main scanning direction. A plurality of ejection element rows 51 exist and are arranged in a second direction that is a direction intersecting the first direction. The second direction substantially coincides with the sub-scanning direction. 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 and the direction in which the extraction electrode 47b extends with respect to the electrode main body 47a is in the sub-scanning direction (x direction, second direction). They are arranged to match.

In a 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. Have been. The directions of the nozzles 33 (leading electrodes 47b) of the adjacent ejection element rows 51 are opposite to each other, and the ejection element rows 51 are half the size of the ejection elements 49 in the main scanning direction and are offset from each other. .

  The two ejection element rows 51 whose nozzles 33 face each other correspond to one ink. In the present embodiment, a total of eight ejection element rows 51 are provided corresponding to four colors. . The number of ejection element rows 51 may be different for each color, such as increasing the number of ejection element rows 51 for black ink.

  As is apparent from the fact that the plurality of ejection elements 49 constitute the plurality of ejection element rows 51, the plurality of pressurizing chambers 35 are arranged in the main scanning direction (the y direction, the 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 channel 37 is connected to the ink supply port 31, and branches along the number of the ejection element rows 51 and extends along the ejection element rows 51.

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

  As shown in FIG. 6A, the FPC 27 includes an insulating base film 55, a conductive pattern 57 formed on the base film 55, and an insulating film 59 covering the conductive pattern 57. The opposing 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, for example, a metal. 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.

  The plurality of wirings 61 extend in parallel with each other (for example, in parallel) along the ejection element rows 51 so as to overlap the ejection element rows 51 (the pressure chamber rows 53). However, the plurality of wirings 61 (the bundle or the arrangement region) extend at a position shifted from the ejection element row 51 to the side opposite to the extraction electrode 47b side. For example, the plurality of wirings 61 do not overlap with the extraction electrode 47b of the pressure chamber 35, but overlap with the other side of the pressure chamber 35 opposite to the extraction electrode 47b. From another viewpoint, the plurality of wirings 61 overlap and extend on the two ejection element rows 51 facing the side opposite to the extraction electrode 47b.

  In FIG. 5, for example, the upper side of the paper (the negative side in the y direction) of the plurality of wirings 61 is the side connected to the driver IC 29. As shown in FIG. 5, the plurality of wirings 61 are formed by bending a lead portion 47b from a first portion extending from the driver IC 29 side along the ejection element row 51 and a wiring portion 61 located outside the first portion. 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) as a connection portion. Thus, the driver IC 29 is electrically connected to the individual electrode 47 via the wiring 61. The FPC 27 is fixed to the piezoelectric actuator substrate 25. The bump 65 may be formed of an appropriate conductive material. For example, the bump 65 is made of a resin (for example, a thermosetting resin) containing particles made of metal (for example, Ag).

  As shown in FIGS. 5 and 6A, the insulating film 59 covers the plurality of wirings 61 by exposing the pad 63. Thereby, the short-circuit between the plurality of wirings 61 due to the adhesion of the conductive material is reduced. In FIG. 5, the range AR indicates the width of the insulating film 59. As described later, a part of the insulating film 59 is formed in a range narrower than the range AR. The insulating film 59 has a width overlapping at least a part of the pressure chamber 35.

  As shown in FIG. 6A, the interposition of the bump 65 between the extraction electrode 47b and the pad 63 allows the individual electrode 47 and the insulating film 59 to be in contact at a relatively low pressure. Alternatively, they face each other with a minute gap (for example, 10 μm or less).

  Note that such a state is realized by, for example, joining the FPC 27 to the piezoelectric actuator substrate 25 as described below. First, an uncured material that becomes the bump 65 is applied on the extraction electrode 47b. Next, the FPC 27 is put on the piezoelectric actuator substrate 25, and the FPC 27 is pressed against the piezoelectric actuator substrate 25. At this time, the material that becomes the bump 65 is crushed (deformed), and the insulating film 59 contacts or approaches the piezoelectric actuator substrate 25. After that, the material that becomes the bump 65 is cured by heating.

  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 smaller on the end side than on the plurality of wirings 61 side. That is, the insulating film 59 has the thick region 59a and the thin region 59b. This change in thickness occurs on the pressure chamber 35. That is, on the pressurizing chamber 35, the thickness T is smaller on the opposite side than on the side of the plurality of wirings 61. In other words, the thickness T is a height from the base film 55 to the surface of the insulating film 59.

  Further, as shown in FIGS. 6A and 6B, the thickness T2 of the insulating film 59 from the base film 55 is reduced in a plurality of portions in the thick region 59a. The thin region extends between the wirings 61 along the y direction in which the wirings 61 extend. That is, the thick portion 59d extending in the y-direction and the thick portion 59d extending in the y-direction have a thickness greater than that of the thick portion 59d. The thin portions 59e are arranged alternately in the x direction. The portion where the thick portions 59d and the thin portions 59e are alternately arranged may be arranged so as to extend 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, depending on the method of forming the insulating film 59, the thickness T of the region where the plurality of wirings 61 are arranged tends to be larger than that of the non-arranged 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 region where the plurality of wirings 61 are arranged, and becomes thinner in the end portion which is the non-arranged region.

  Instead of or in addition to this method, for example, after a material such as a solder resist is applied to the entire region where the insulating film 59 is formed, the material may be applied again only to the region where the thickness T is to be increased. Further, 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 to be reduced is pressed by 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 specifically shown, the piezoelectric actuator substrate 25 is provided with a pad connected to the common electrode 43, and the wiring and the pad of the FPC 27 are joined to the pad, so that the driver IC 29 electrically connects the common electrode 43 to the common electrode 43. Connected.

  For example, data of the amount of ink to be ejected from all the nozzles 33 is input from the control unit 11 to the driver IC 29 at every predetermined drive cycle. The driver IC 29 applies, for example, 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. The driver IC 29 sets, for example, the number of times a drive signal is output within a drive cycle based on input data.

  As described above, in the present embodiment, the head 5 has 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 pressure 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-shaped member 39 is further laminated on the side where the pressurizing chamber 35 is open may be used so as to close the pressurizing chamber 35. By disposing the pressure 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 pressure chamber 35 is stacked on the pressure chamber 35. The pressure is transmitted to the pressurizing chamber 35 through the plate member 39 thus formed. By doing so, for example, the possibility that the solvent of the ink or the like affects the reliability of the piezoelectric actuator substrate 25 can be reduced. The piezoelectric actuator substrate 25 is overlaid on the second surface 23b and closes 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 disposed so as to face the opposite side of the piezoelectric actuator 23 and 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 depends 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 thick portion of the insulating film 59 serves as a spacer, and the thin portion of the insulating film 59 is suppressed from contacting the piezoelectric actuator substrate 25 (the individual electrode 47). As a result, the effect of the FPC 27 on the operation of the piezoelectric actuator substrate 25 can be reduced. Specifically, for example, the load of the FPC 27 is suppressed from being applied to the piezoelectric actuator substrate 25 on the pressure chamber 35. Further, for example, since the FPC 27 is suppressed from being in close contact with the individual electrode 47 in at least a part of the pressurized chamber 35, when the individual electrode 47 separates from the FPC 27, air easily enters between them, and 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 connection portions. The plurality of connection portions (bumps 65) are arranged side by side in the y direction to form a connection portion row 66. The plurality of connection 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 flexed in the x direction, so that the piezoelectric actuator The effect on the operation of the substrate 25 can be further reduced.

Further, by disposing the thin portion 59e between the adjacent wires 61, the wires 61 are disposed on the thick portions 59d, so that the wires 61 are exposed, and the occurrence of disconnection or the like is suppressed. it can.

  Further, in the present embodiment, the plurality of wirings 61 are located on one side on the pressure 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 easily increased on the pressurizing chamber 35 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 47b is drawn out of the pressure chamber 35 on the side where the thickness T of the insulating film 59 from the base film 55 is thin. The portion where the extraction electrode 47b exists is a portion where the vibration generated by the application of the drive signal is large in the peripheral portion of the pressurizing chamber 35, and is a portion which is greatly affected by the proximity of the insulating film 59. Since the thickness T of the insulating film 59 on the side from which the extraction electrode 47b is extended is small, this effect can be suppressed.

  In addition, since a portion where the insulating film 59 is formed on the wiring 61 has a high possibility of affecting the operation of the piezoelectric actuator substrate 25, such a portion is preferably reduced. When the insulating film 59 has a planar shape, a concave portion 59f in which the outer edge of the insulating film 59 on the wiring 60 is concave with respect to the outer edge of the insulating film 59 on the surrounding base film 55 is arranged on the wiring 60 when the planar shape. Is less likely to affect the operation of the piezoelectric actuator substrate 25. The concave portion 59f can be formed by patterning and applying a solder resist to be the insulating film 59. Further, if a solder resist having poor wettability is used for the insulating film 59, the solder resist escapes from the wiring 60 at the outer edge of the insulating film 59 without forming a pattern, and the recess 59f is formed. it can.

  If the concave portion 59f is arranged at a second portion where the wiring 60 is bent toward the bump 65 from the first portion where the wiring 60 extends in the y direction, the possibility of affecting the operation of the piezoelectric actuator substrate 25 can be reduced. In addition, since the second portion has a large portion facing the individual electrode 47 to which the wiring 60 is electrically connected, even if the second portion is in contact with the individual electrode 47, the individual electrode which is not electrically connected is not designed. It is possible to reduce the possibility of supplying a voltage to the 47.

  Further, it is preferable that the concave portion 59f is disposed so as to overlap with a region between the individual electrodes 47 adjacent in the y direction. Thereby, the portion where the insulating film 59 overlaps the wiring 60 existing adjacent to the concave portion 59f in the first place becomes less likely to overlap the pressurizing chamber 35, and the possibility of affecting the operation of the piezoelectric actuator substrate 25 can be reduced. .

  In addition, it is preferable that the concave portion 59f has a shape that does not extend to the first portion where the plurality of wirings 60 are arranged side by side and extend in the y direction. By doing so, a short circuit or the like can be made less likely to occur in the first portion where the wiring 60 is disposed close to the first portion.

  FIG. 7 is a cross-sectional view illustrating a modification of the FPC 27 and corresponding to FIG.

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

  The second thick region 59c may be formed by the same method as forming the thick region 59a on the thin region 59b. For example, in the second thick region 59c, the density of the wiring 61 is made higher than that in the thick region 59a, and the material that becomes 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 contact of the insulating film 59 with the piezoelectric actuator substrate 25 (individual electrode 47) on the pressurizing chamber 35 is further suppressed, 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. Therefore, 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 FPC 27 (the base film 55) is suppressed from being in contact with the piezoelectric actuator substrate 25 in a part of the region on the pressurizing chamber 35 by the insulating film 59 serving as a spacer. As a result, the effect of the FPC 27 on the operation of the piezoelectric actuator substrate 25 can be further reduced.

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

  In the embodiment, as described with reference to FIG. 5, the plurality of wirings 61 are bent outward in order from the outer wiring and extended to the extraction electrode 47b. As a result, the width of the arrangement region of the plurality of wirings 61 gradually narrowed. 8A and 8B, the conductor pattern 57 is formed such that the width of the arrangement region of the plurality of wirings is kept constant over the plurality of pressure 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 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, as the plurality of wirings 61 extend from the driver IC 29 side along the pressurizing chamber row 53, the width of the remaining wirings 61 gradually increases. In FIG. 8B, the entire width of the remaining wiring 61 is gradually increased, but the width of a specific wiring 61 may be increased.

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

  Here, the term “the width of the wiring arrangement area is constant” means that the change in the width of the wiring arrangement area is smaller than that in the embodiment described with reference to FIG. Therefore, for example, if the change in the width of the arrangement area of the plurality of wirings over the plurality of pressurization chambers 35 is smaller than the width of the single wiring 61, the width of the arrangement area of the plurality of wirings becomes the plurality of pressure chambers. It is constant 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. A 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%, except for the above-mentioned local change.

  The present disclosure is not limited to the above embodiments or modified examples, and may be implemented 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 ink jet head (for example, a medium transport unit) in the printer may be an appropriate configuration other than the illustrated configuration. The media is not limited to paper, but may be metal or resin.

Reference Signs List 5 Head 23 Flow path member 23a First surface 23b Second surface 33 Nozzle 35 Pressurizing chamber 25 Piezoelectric actuator substrate 27 FPC (Flexible wiring board)
55 base film 59 insulating film 59a thick film region 59b thin film region 59c second thick film region 59d thick film portion 59e thin film portion 59f・ Concave part 61 ・ ・ ・ Wiring 65 ・ ・ ・ Bump (connection part)
66 ・ ・ ・ Connection part line

Claims (5)

A plurality of nozzles opening to the first surface, and a flow path member having a pressurized chamber located on the second surface side opposite to the first surface and connected to the plurality of nozzles,
A piezoelectric actuator substrate overlapping the second surface so as to cover the plurality of pressure chambers;
A base film, a plurality of wirings provided on the base film, and a flexible wiring board having an insulating film covering a part of the plurality of wirings, and being electrically connected to the piezoelectric actuator substrate;
Has,
The flexible wiring board is arranged with the insulating film side facing the piezoelectric actuator substrate,
The wiring has an exposed portion that is not covered with the insulating film, and a covering portion that is covered with the insulating film,
The insulating film, the outer edge of the insulating film on the wiring, has a concave portion is recessed in a planar shape with respect to the outer edge of the insulating film on the surrounding base film ,
The piezoelectric actuator substrate and the flexible wiring substrate are electrically connected at a plurality of connection portions,
When viewed from above,
On the piezoelectric actuator substrate, a plurality of connection portion rows in which a plurality of the connection portions are arranged along a first direction are arranged in a second direction that is a direction intersecting with the first direction. And
The ink jet head, wherein the concave portion and the pressurizing chamber are arranged between the connecting portion rows . When viewed from above,
The wiring has a first portion extending in the first direction between the connection portion rows, and a second portion bent from the first portion and connected to the connection portion,
Said recess, said together is disposed in the second portion, inkjet Tsu collector head according to claim 1, characterized in that does not extend up to the first site. The piezoelectric actuator substrate is electrically connected to each of the plurality of connection portions, and a plurality of individual electrodes that can respectively press the plurality of pressurization chambers are arranged,
When viewed from above,
The plurality of individual electrodes are arranged along the first direction between the connection section rows,
Inkjet Tsu collector head according to claim 2, characterized in that said second portion, and the region between the individual electrodes that are adjacent overlap. A thick portion extending along the first direction and a thick portion extending along the first direction at a portion of the insulating film overlapping with the pressurizing chamber, and extending from the base film of the insulating film. wherein the thickness as thin walled portion than the thick section, inkjet Tsu collector head according to any one of claims 1 to 3, characterized in that are arranged alternately in the second direction. Printer, characterized in that it comprises an inkjet head according to any one of claims 1-4, a scanning unit for relatively moving the medium and the inkjet head, and a control unit that controls the inkjet head .

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