JP4240125B2 - Inkjet head manufacturing method, inkjet head inspection method, and inkjet recording apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing an ink jet head that performs printing by discharging ink droplets, a method for inspecting an ink jet head, and an ink jet recording apparatus.

  As an inkjet head for ejecting ink droplets onto a recording medium such as printing paper, a flow path unit having a number of individual ink flow paths including a nozzle for ejecting ink droplets and a pressure chamber communicating with the nozzle, and each pressure chamber And an actuator for applying ejection energy to the ink. This actuator applies pressure to the pressure chamber by changing the volume of the pressure chamber, and is arranged so as to oppose each pressure chamber on the surface of the piezoelectric sheet across the many pressure chambers and the piezoelectric sheet. One having a large number of individual electrodes and a common electrode arranged to face the large number of individual electrodes via a piezoelectric sheet is known (for example, see Patent Document 1). On the surface of this actuator, connection lands for individual electrodes and common electrodes are arranged, and these connection lands are joined to a large number of terminals arranged near one end of a flat cable (flat flexible substrate). . The flat cable supplies a drive signal to the actuator via a terminal connected to the internal wiring. The actuator is supplied with a pulsed drive signal to each individual electrode via a flat cable, so that an electric field is applied in the thickness direction to the portion of the piezoelectric sheet sandwiched between the individual electrode and the common electrode. It acts, and the piezoelectric sheet of this part is extended in the thickness direction. At this time, the volume of the pressure chamber changes and pressure is applied to the ink in the pressure chamber.

Japanese Patent Laid-Open No. 2002-36568 (FIG. 1)

  The flat cable is joined to the surface of the actuator in the vicinity of one end thereof, and is connected to an upper control board or the like at the other end. At this time, due to the handling of the flat cable, stress may be generated at the joint portion of the flat cable with the actuator, and the terminal of the flat cable may be separated from the connection land of the actuator. The occurrence of such poor bonding between the flat cable and the actuator causes a decrease in the yield of the inkjet head. Therefore, in the manufacturing process of the inkjet head and the inspection of the inkjet head, the joining conditions must be adjusted so that the flat cable and the actuator are reliably joined. In order to adjust the joining conditions, it is necessary to grasp how far the flat cable is separated from the actuator under the current joining conditions. However, it is difficult to visually confirm the joining state between the flat cable terminal and the connecting land of the actuator.

  An object of the present invention is to provide an ink jet head manufacturing method, an ink jet head inspection method, and an ink jet recording apparatus capable of easily grasping how far a flat flexible substrate is peeled from an actuator.

  The inkjet head manufacturing method of the present invention includes a flow path unit in which a plurality of individual ink flow paths reaching a nozzle through a pressure chamber, a plurality of individual electrodes, a common electrode, the plurality of individual electrodes, and the common electrode. The plurality of pressure chambers and the plurality of individual electrodes face each other between a piezoelectric layer disposed between the actuator and an actuator having a plurality of individual lands electrically connected to the plurality of individual electrodes. A plurality of output terminals and a flat flexible substrate having a plurality of inspection terminals, the plurality of inspection terminals on a joint surface on the opposite side of the flow path unit in the actuator. A bonding step of bonding to the actuator so that the plurality of output terminals and the plurality of individual lands are bonded to each other. Further, based on the measurement step of measuring the electrical characteristics of the plurality of inspection terminals in the flat flexible substrate bonded to the bonding surface of the actuator, and the measurement result of the measurement step, from the bonding surface of the actuator And a determination step of determining the number of the inspection terminals that have been peeled off.

  The inkjet head inspection method of the present invention includes a flow path unit in which a plurality of individual ink flow paths reaching a nozzle through a pressure chamber are formed, and is fixed to the flow path unit, and the plurality of pressure chambers A plurality of associated individual electrodes, a common electrode, a piezoelectric layer disposed between the plurality of individual electrodes and the common electrode, and a bonding surface opposite to the fixed surface of the flow path unit. While an actuator having a plurality of individual lands electrically connected to the plurality of individual electrodes, a plurality of output terminals joined to the plurality of individual lands, and a plurality of joints joined to the joint surfaces of the actuator An inspection method for an ink jet head having a flat flexible substrate having an inspection terminal. And a measuring step of measuring electrical characteristics of the plurality of inspection terminals, and a determination step of determining the number of the inspection terminals peeled from the joint surface of the actuator based on a measurement result of the measuring step. Yes.

  The inkjet recording apparatus of the present invention includes a flow path unit in which a plurality of individual ink flow paths reaching the nozzles via pressure chambers are formed, and is fixed to the flow path unit and is associated with the plurality of pressure chambers. A plurality of individual electrodes, a common electrode, a piezoelectric layer disposed between the plurality of individual electrodes and the common electrode, and a bonding surface opposite to a fixed surface of the flow path unit An actuator having a plurality of individual lands electrically connected to a plurality of individual electrodes, a plurality of output terminals joined to the plurality of individual lands, and a plurality of inspection terminals joined to the joint surfaces of the actuator And a flat flexible substrate. Furthermore, a measurement unit that measures electrical characteristics of the plurality of inspection terminals, and a determination unit that determines the number of the inspection terminals peeled from the joint surface of the actuator based on a measurement result of the measurement unit. Yes.

  According to these aspects of the present invention, it is possible to easily grasp how much the flat flexible substrate is peeled off from the actuator by judging the number of inspection terminals peeled off from the joint surface of the actuator. Thereby, it becomes easy to adjust the joining conditions in the joining process, and the yield of the inkjet head can be improved. In addition, the inkjet head can be inspected to easily determine whether or not the flat flexible substrate may be peeled off from the actuator and cause a failure.

  In the present invention, it is preferable that the capacitance between the common electrode and each inspection terminal is measured in the measurement step.

  Alternatively, the inspection terminal and an inspection individual electrode that is one of the plurality of individual electrodes are electrically connected, and in the measurement step, between the common electrode and the inspection terminal, and the common electrode It is preferable to measure the total value of each electrostatic capacitance between the inspection individual electrode and the inspection individual electrode.

  Further, the actuator further includes an inspection land that is disposed on the bonding surface and is electrically connected to the common electrode. In the bonding step, the inspection terminal is connected to the inspection land via the inspection land. It is preferable to join the joint surface of the actuator and measure a resistance value between the common electrode and each inspection terminal in the measurement step.

  Alternatively, the flow path unit includes a metal member, and the actuator further includes an inspection land disposed on the joint surface, and the inspection land is electrically connected to the metal member in the fixing step. The actuator is fixed to the flow path unit so as to be connected, and in the joining step, the inspection terminal is joined to the joint surface of the actuator via the inspection land, and in the measurement step, the metal It is preferable to measure a resistance value between the member and each inspection terminal.

  Furthermore, in the measurement step, it is preferable to measure electrical characteristics of the inspection terminal based on current consumption when an inspection signal is output to the inspection terminal.

  According to these, it is possible to easily determine whether or not each inspection terminal has been peeled off from the joint surface of the actuator.

  In the present invention, in the joining step, the flat flexible substrate is joined to the actuator such that the flat flexible substrate extends from the actuator toward one side, and the plurality of flat flexible substrates are arranged. It is preferable that the inspection terminals are arranged along the one side. According to this, by detecting the number of inspection terminals peeled from the joint surface of the actuator, it is possible to accurately grasp how far the flat flexible substrate is peeled from the actuator.

  At this time, it is preferable that at least one of the plurality of inspection terminals of the flat flexible substrate is disposed on the one side of the plurality of output terminals. According to this, it can suppress efficiently that a flat flexible board | substrate peels from an actuator.

  Furthermore, in the present invention, it is more preferable that the plurality of inspection terminals of the flat flexible substrate are arranged on both sides in a direction orthogonal to the one of the plurality of output terminals. According to this, it can suppress more efficiently that a flat flexible board | substrate peels from an actuator.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic side view showing an overall configuration of an ink jet printer according to a first embodiment of the present invention. As shown in FIG. 1, the inkjet printer 101 is a color inkjet printer having four inkjet heads 1. The inkjet printer 101 includes a paper feeding unit 11 on the left side in the drawing and a paper discharge unit 12 on the right side in the drawing.

  Inside the ink jet printer 101, a paper transport path is formed through which paper (recording medium) P is transported from the paper supply unit 11 toward the paper discharge unit 12. A pair of feed rollers 5a and 5b for nipping and conveying the paper are arranged immediately downstream of the paper supply unit 11. The pair of feed rollers 5a and 5b are for feeding the paper P from the paper feeding unit 11 to the right in the drawing. In an intermediate portion of the paper conveyance path, two belt rollers 6 and 7, an endless conveyance belt 8 wound around the rollers 6 and 7, and an area surrounded by the conveyance belt 8 A belt conveyance mechanism 13 including a platen 15 disposed in a position facing the inkjet head 1 is provided. The platen 15 supports the conveyance belt 8 so that the conveyance belt 8 does not bend downward in a region facing the inkjet head 1. A nip roller 4 is disposed at a position facing the belt roller 7. The nip roller 4 presses the sheet P fed from the sheet feeding unit 11 by the feed rollers 5 a and 5 b against the outer peripheral surface 8 a of the transport belt 8.

  The conveyor belt 8 is driven by a conveyor motor (not shown) rotating the belt roller 6. Thereby, the conveyance belt 8 conveys the paper P pressed against the outer peripheral surface 8 a by the nip roller 4 toward the paper discharge unit 12 while being adhesively held.

  A peeling mechanism 14 is provided immediately downstream of the conveying belt 8 along the sheet conveying path. The peeling mechanism 14 is configured to peel the paper P adhered to the outer peripheral surface 8a of the conveyor belt 8 from the outer peripheral surface 8a and send it to the right paper discharge unit 12 on the left side in the drawing. .

  The four inkjet heads 1 are fixed side by side along the transport direction corresponding to four color inks (magenta, yellow, cyan, and black). That is, the ink jet printer 101 is a line printer. Each of the four inkjet heads 1 has a head body 2 at the lower end thereof. The head main body 2 has an elongated rectangular parallelepiped shape that is long in a direction orthogonal to the transport direction. Further, the bottom surface of the head main body 2 is an ink ejection surface 2a that faces the outer peripheral surface 8a. When the paper P transported by the transport belt 8 sequentially passes immediately below the four head bodies 2, ink of each color is ejected from the ink ejection surface 2a toward the upper surface of the paper P, that is, the printing surface. Thus, a desired color image can be formed on the printing surface of the paper P.

  Next, the inkjet head 1 will be described in detail with reference to FIG. FIG. 2 is a cross-sectional view of the inkjet head 1 along the short direction. As shown in FIG. 2, the inkjet head 1 includes a head body 2 including a flow path unit 9 and an actuator unit 21, a reservoir unit 71 that is disposed on the upper surface of the head body 2 and supplies ink to the head body 2, One end is connected to the actuator unit 21, a driver IC 52 is mounted on a COF (Chip On Film: flat flexible substrate) 50, a control board 54 electrically connected to the COF 50, an actuator unit 21, a reservoir unit 71, A side cover 53 and a head cover 55 are provided to cover the COF 50 and the control board 54 and prevent ink and ink mist from entering from the outside.

  The reservoir unit 71 is formed by stacking four plates 91 to 94 that are aligned with each other. Inside the reservoir unit 71, an ink inflow channel (not shown), an ink reservoir 61, and 10 ink outflow flows are provided. The passages 62 are formed so as to communicate with each other. In FIG. 2, only one ink outflow channel 62 appears. The ink inflow channel is a channel into which ink from an ink tank (not shown) flows. The ink reservoir 61 is in communication with the ink inflow channel and the ink outflow channel 62, and temporarily stores ink. The ink outflow channel 62 communicates with the channel unit 9 via an ink supply port 105 b (see FIG. 3) formed on the upper surface of the channel unit 9. Ink from the ink tank flows into the ink reservoir 61 through the ink inflow channel. The ink flowing into the ink reservoir 61 passes through the ink outflow channel 62 and is supplied to the channel unit 9 via the ink supply port 105b.

  Further, the plate 94 has a recess 94a. In the portion of the plate 94 where the concave portion 94a is formed, a gap is formed between the plate unit 94 and the flow path unit 9, and the actuator unit 21 is disposed in this gap.

  One end of the COF 50 is bonded to a joint surface that is the upper surface of the actuator unit 21. Further, the COF 50 extends from the joint surface of the actuator unit 21 in the horizontal direction, and then is bent so as to be bent at a right angle upward, and further passes between the side cover 53 and the reservoir unit 71. It is pulled out upward. The other end of the COF 50 is connected to the connector 54a of the control board 54 via the connector 54a. For this reason, stress concentrates in the direction in which the COF 50 is peeled from the actuator unit 21 in the region located closest to the bent portion of the COF 50 on the joint surface of the actuator unit 21.

  Further, the driver IC 52 of the COF 50 is urged against the side cover 53 by a sponge 82 attached to the side surface of the reservoir unit 71. The driver IC 52 is thermally coupled to the side cover 53 by being in close contact with the inner surface of the side cover 53 via the heat dissipation sheet 81. Thereby, heat from the driver IC 52 is radiated to the outside through the side cover 53.

  The control board 54 controls driving of the actuator unit 21 via the driver IC 52 of the COF 50. The driver IC 52 generates a drive signal that drives the actuator unit 21.

  The side cover 53 is a metal plate member attached so as to extend upward from the vicinity of both ends in the lateral direction on the upper surface of the flow path unit 9. The head cover 55 is attached above the side cover 53 so as to seal the space above the flow path unit 9. As described above, the reservoir unit 71, the COF 50, and the control board 54 are arranged in the space surrounded by the two side covers 53 and the head cover 55.

  Next, the head body 2 will be described with reference to FIGS. FIG. 3 is a plan view of the head body 2. FIG. 4 is an enlarged view of a region surrounded by a one-dot chain line in FIG. In FIG. 4, for convenience of explanation, the pressure chamber 110, the aperture 112, and the nozzle 108 that are to be drawn by broken lines below the actuator unit 21 are drawn by solid lines. FIG. 5 is a partial cross-sectional view taken along line VV shown in FIG. 6A is an enlarged cross-sectional view of the actuator unit 21, and FIG. 6B is a plan view showing individual electrodes arranged on the surface of the actuator unit 21 in FIG. 6A.

  As shown in FIG. 3, the head body 2 includes a flow path unit 9 and four actuator units 21 fixed to the upper surface 9 a of the flow path unit 9. As shown in FIG. 4, the flow path unit 9 has an ink flow path including a pressure chamber 110 and the like formed therein. The actuator unit 21 includes a plurality of actuators corresponding to the pressure chambers 110, and has a function of selectively giving ejection energy to the ink in the pressure chambers 110.

  The flow path unit 9 has a rectangular parallelepiped shape that has substantially the same planar shape as the plate 94 of the reservoir unit 71. A total of ten ink supply ports 105b are opened on the upper surface 9a of the flow path unit 9 corresponding to the ink outflow flow path 62 (see FIG. 2) of the reservoir unit 71. As shown in FIGS. 3 and 4, a manifold channel 105 communicating with the ink supply port 105 b and a sub-manifold channel 105 a branched from the manifold channel 105 are formed inside the channel unit 9. As shown in FIGS. 4 and 5, an ink discharge surface 2 a in which a large number of nozzles 108 are arranged in a matrix is formed on the lower surface of the flow path unit 9. A large number of pressure chambers 110 are also arranged in a matrix like the nozzles 108 on the fixed surface of the actuator unit 21 in the flow path unit 9.

  In the present embodiment, 16 rows of pressure chambers 110 arranged at equal intervals in the longitudinal direction of the flow path unit 9 are arranged in parallel to each other in the short direction. The number of pressure chambers 110 included in each pressure chamber row corresponds to the outer shape (trapezoidal shape) of an actuator unit 21 described later, from the long side (lower base side) to the short side (upper base side). It arrange | positions so that it may decrease gradually toward it. The nozzle 108 is also arranged in the same manner.

  As shown in FIG. 5, the flow path unit 9 includes a cavity plate 122, a base plate 123, an aperture plate 124, a supply plate 125, manifold plates 126, 127, and 128, a cover plate 129, and a nozzle plate 130 in order from the top. It consists of nine metal plates such as stainless steel. These plates 122 to 130 have a rectangular plane elongated in the main scanning direction. By laminating these plates 122 to 130 while being aligned with each other, the nozzle 108 in the flow path unit 9 passes from the manifold flow path 105 to the sub manifold flow path 105a and from the outlet of the sub manifold flow path 105a through the pressure chamber 110. A large number of individual ink channels 132 are formed.

  The ink flow in the flow path unit 9 will be described. As shown in FIGS. 3 to 5, the ink supplied from the reservoir unit 71 into the flow path unit 9 through the ink supply port 105 b is branched from the manifold flow path 105 to the sub-manifold flow path 105 a. The ink in the sub-manifold channel 105a flows into each individual ink channel 132 and reaches the nozzle 108 through the aperture 112 and the pressure chamber 110 functioning as a throttle.

  Next, the actuator unit 21 will be described. As shown in FIG. 3, each of the four actuator units 21 has a trapezoidal planar shape, and is arranged in a staggered manner so as to avoid the ink supply ports 105b. Furthermore, the parallel opposing sides of each actuator unit 21 are along the longitudinal direction of the flow path unit 9, and the oblique sides of the adjacent actuator units 21 overlap each other in the width direction (sub-scanning direction) of the flow path unit 9. Yes.

  As shown in FIG. 6A, the actuator unit 21 includes three piezoelectric sheets 141 to 143 made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity. An individual electrode 135 is formed at a position facing the pressure chamber 110 on the surface of the uppermost piezoelectric sheet 141 (joint surface of the actuator unit 21). A common electrode 134 formed on the entire surface of the sheet is interposed between the uppermost piezoelectric sheet 141 and the lower piezoelectric sheet 142. As shown in FIG. 6B, the individual electrode 135 has a substantially rhombic planar shape similar to the pressure chamber 110. In plan view, most of the individual electrodes 135 are in the region of the pressure chamber 110. One of the acute angle portions of the substantially rhomboid individual electrode 135 extends out of the pressure chamber 110, and a circular individual land 136 electrically connected to the individual electrode 135 is provided at the tip thereof. Further, on the surface of the piezoelectric sheet 141, a COM land (not shown) and an inspection land 137 (see FIGS. 7 and 9) electrically connected to the common electrode 134 are formed. Note that four inspection lands 137 are arranged in the vicinity of each end portion with respect to the long side (the bottom of the trapezoid) of the piezoelectric sheet 141 along the direction orthogonal to the long side of the actuator unit 21. Further, two of the four inspection lands 137 arranged in the vicinity of each end are disposed at positions closer to the end on the longer side than the large number of individual electrodes 135. Further, the surface of the piezoelectric sheet 141 is a bonding surface to which the COF 50 is bonded as described later.

  The common electrode 134 is equally grounded in the region corresponding to all the pressure chambers 110. On the other hand, the individual electrode 135 is electrically connected to each output terminal of the driver IC 52 via the COF 50, and a drive signal from the driver IC 52 is selectively supplied.

  Here, a driving method of the actuator unit 21 will be described. The piezoelectric sheet 141 is polarized in the thickness direction. When an electric field is applied to the piezoelectric sheet 141 by setting the individual electrode 135 to a potential different from that of the common electrode 134, the electric field application portion of the piezoelectric sheet 141 has a piezoelectric effect. Acts as an active part that is distorted by That is, in the actuator unit 21, a portion sandwiched between the individual electrode 135 and the pressure chamber 110 functions as an individual actuator, and a plurality of actuators corresponding to the number of pressure chambers 110 are formed. For example, if the polarization direction is the same as the electric field application direction, the active portion contracts in a direction (plane direction) perpendicular to the polarization direction. That is, the actuator unit 21 uses the upper one piezoelectric sheet 141 away from the pressure chamber 110 as a layer including an active portion, and the lower two piezoelectric sheets 142 and 143 close to the pressure chamber 110 as inactive layers. This is a so-called unimorph type actuator. As shown in FIG. 6A, since the piezoelectric sheets 141 to 143 are fixed to the upper surface of the cavity plate 122 that partitions the pressure chamber 110, the electric field application portion of the piezoelectric sheet 141 and the piezoelectric sheets 142 and 143 below the electric field application portion. If there is a difference in distortion in the plane direction between the piezoelectric sheets 141 and 143, the entire piezoelectric sheets 141 to 143 are deformed so as to be convex toward the pressure chamber 110 (unimorph deformation). As a result, pressure (discharge energy) is applied to the ink in the pressure chamber 110, and an ink droplet is discharged from the nozzle 108.

  In the present embodiment, a predetermined potential is applied to the individual electrode 135 in advance, and the individual electrode 135 is once set to the ground potential every time there is an ejection request, and then the individual electrode 135 is again set to the predetermined potential at a predetermined timing. A drive signal for applying a potential is output from the driver IC 52. In this case, the piezoelectric sheets 141 to 143 return to the original state at the timing when the individual electrode 135 becomes the ground potential, and the volume of the pressure chamber 110 increases as compared with the initial state (a state in which a voltage is applied in advance). Ink is sucked from the manifold channel 105 a into the individual ink channel 132. After that, at the timing when a predetermined potential is applied to the individual electrode 135 again, the piezoelectric sheets 141 to 143 are deformed so that the portions facing the active region protrude toward the pressure chamber 110, and the ink is reduced due to the volume reduction of the pressure chamber 110. The pressure increases, and ink is ejected from the nozzle 108.

  Next, the COF 50 will be described in detail with reference to FIG. FIG. 7 is a plan view of the COF 50. In FIG. 7, the length of the COF 50 in the longitudinal direction is shortened for convenience of explanation. As shown in FIG. 7, the COF 50 includes a terminal arrangement region 50 a having a trapezoidal planar outline substantially the same as that of the actuator unit 21, and a wiring region 50 b extending outward from the long side of the terminal arrangement region 50 a. And a terminal 50c disposed at the end of the wiring region 50b connected to the connector 54a of the control board 54.

  The terminal arrangement region 50 a is a region bonded to the bonding surface of the actuator unit 21. In the terminal arrangement region 50a, a number of output terminals 58 joined to the individual lands 136 of the individual electrodes 135, and a ground terminal 60 joined to a COM land (not shown) electrically connected to the common electrode 134, The eight inspection terminals 59a to 59d joined to the inspection land 137 (see FIG. 9) are arranged. In the vicinity of each end portion with respect to the long side of the terminal arrangement region 50a (the bottom of the trapezoidal shape), the four inspection terminals 59a to 59d extend in the COF 50 extending direction from the long side in the terminal arrangement region 50a, that is, from the wiring region 50b side. The test terminals are arranged in the order of inspection terminal 59a → inspection terminal 59b → inspection terminal 59c → inspection terminal 59d. These four inspection terminals 59a to 59d are electrically connected to each other. Of the four test terminals 59a to 59d arranged in the vicinity of each end, two test terminals 59a and 59b positioned on the long side of the terminal arrangement region 50a are longer than the many output terminals 58. Is arranged. Therefore, in a state where the COF 50 is bonded to the bonding surface of the actuator unit 21, the inspection terminals 59a to 59d are in the vicinity of each end portion with respect to the long side (the lower bottom of the trapezoidal shape) of the piezoelectric sheet 141, and the COF 50 is pulled out. 4 are arranged along each. Further, a total of four inspection terminals 59a and 59b are arranged near both ends of the long side of the actuator unit 21 and at positions closer to the end of the COF 50 in the lead-out direction side of the joint surface than the large number of individual electrodes 135. .

  A driver IC 52 is mounted at the center of the wiring region 50b (center in the width direction). The wiring area 50b includes an output wiring 57a that connects an output terminal (not shown) of the driver IC 52 and the output terminal 58, a control wiring 57b that connects a control terminal (not shown) of the driver IC 52 and the terminal 50c, and a terminal arrangement area. Inspection wirings 73 are formed which are electrically connected to four inspection terminals 59a to 59d arranged in the vicinity of the respective end portions relating to the long side of 50a. In the vicinity of both ends of the COF 50 in the lateral direction, COM patterns 72 extending along the outer edges of the terminal arrangement region 50a and the wiring region 50b are formed. The ground terminal 60 is arranged in the COM pattern 72 in the terminal arrangement region 50a.

  The terminal 50 c is connected to the connector 54 a of the control board 54, and has a large number of terminals (not shown) connected to the control wiring 57 b and the COM pattern 72.

  Next, the driver IC 52 will be described in detail with reference to FIGS. FIG. 8 is a functional block diagram of the driver IC 52. FIG. 9 is a diagram for explaining the positional relationship between the inspection terminals 59 a to 59 d and the common electrode 134. 9A is a partially enlarged plan view of the COF 50 and the actuator unit 21, and FIG. 9B is a partial cross-sectional view of the COF 50 and the actuator unit 21 when the COF 50 is not peeled from the actuator unit 21. FIG. 9C is a partial cross-sectional view of the COF 50 and the actuator unit 21 when the COF 50 is peeled from the actuator unit 21. 9B and 9C, only the inspection terminal 59a among the four inspection terminals 59a to 59d appears. FIG. 10 is a partial cross-sectional view taken along the line XX shown in FIG. 9A when the COF 50 is peeled from the actuator unit 21.

  As shown in FIG. 8, the driver IC 52 includes a drive signal output unit (drive signal output member) 81, an electrical characteristic measurement unit (measurement unit) 82, a peeling determination unit (determination unit) 83, and a communication unit 84. Have. The drive signal output unit 81 outputs a drive signal for driving the actuator unit 21 based on a command from a host device (not shown) (for example, a host computer). The drive signal output from the drive signal output unit 81 is supplied from the output terminal of the driver IC 52 to the corresponding individual electrode 135 via the output wiring 57 a and the output terminal 58.

  As shown in FIGS. 9A and 9B, when the COF 50 is not peeled from the actuator unit 21, the inspection terminal 59a and the common electrode 134 are close to each other via the piezoelectric sheet 141. The capacitance between the inspection terminal 59a and the common electrode 134 is about 10 pF. Further, as shown in FIG. 9C, when the inspection terminal 59a is peeled from the inspection land 137, the inspection terminal 59a and the common electrode 134 do not come close to each other. The capacitance becomes 0 pF.

  As shown in FIG. 10, when the COF 50 is peeled off from the actuator unit 21, the four inspection terminals 59a to 59d are in order from the wiring region 50b side, specifically, the inspection terminal 59a → the inspection terminal 59b → the inspection terminal 59c → It peels from the inspection land 137 in the order of the inspection terminal 59d. Thus, the number of inspection terminals 59a to 59d peeled from the inspection land 137 varies depending on the degree to which the COF 50 peels from the actuator unit 21. Therefore, the total value of the capacitance between the four inspection terminals 59a to 59d and the common electrode 134 varies depending on the degree to which the COF 50 is peeled from the actuator unit 21. That is, when the four inspection terminals 59a to 59d are not peeled from the inspection land 137, the total value of the capacitance is about 10 × 4 = 40 pF. When only the inspection terminal 59a is peeled from the inspection land 137, the total value of the capacitance is about 3 × 10 = 30 pF. Further, when the inspection terminals 59a and 59b are separated from the inspection land 137, the total value of the capacitance is about 2 × 10 = 20 pF. Further, when the inspection terminals 59a to 59c are peeled off from the inspection land 137, the total value of the capacitance is about 1 × 10 = 10 pF. Finally, when all the inspection terminals 59a to 59d are peeled off from the inspection land 137, the total value of the capacitance becomes 0 pF.

  The electrical characteristic measurement unit 82 measures electrical characteristics of the inspection terminals 59a to 59d, and includes a capacitance measurement circuit 82a. The electrostatic capacitance measuring circuit 82a has, as electrical characteristics of the inspection terminals 59a to 59d, electrostatic capacitances between the four inspection terminals 59a to 59d and the common electrode 134 disposed in the vicinity of each end portion of the long side of the actuator unit 21. Measure the total capacity.

  The capacitance measuring circuit 82a will be described with further reference to FIG. FIG. 11 is a schematic circuit diagram showing the internal configuration of the capacitance measuring circuit 82a. The capacitance measuring circuit 82 a has a pair of inverters 96 and 97 and an A / D converter 98. The inverter 96 outputs the inspection pulse signal to the inspection terminal 59a via the drive resistor R1 when the pulse signal is input. The inverter 97 outputs the inspection pulse signal from the inverter 96 to the A / D converter 98. The A / D converter 98 outputs the output potential from the inverter 97 as a digital signal. As described above, when the COF 50 is not peeled off from the actuator unit 21, the total value of the capacitance between the four inspection terminals 59 a to 59 d and the common electrode 134 is about 40 pF, and the inspection pulse from the inverter 96 is obtained. The rise time and fall time of the signal are longer than the input pulse signal. When the COF 50 is peeled from the actuator unit 21 and peeled from the inspection land 137 in the order of the inspection terminal 59a → the inspection terminal 59b → the inspection terminal 59c → the inspection terminal 59d, the four inspection terminals 59a to 59d and the common electrode 134 The total value of the capacitance during the period changes in the order of 30 pF → 20 pF → 10 pF → 0 pF. Along with this change, when the rising time and falling time of the inspection pulse signal from the inverter 96 are reduced stepwise, and finally when the total capacitance becomes 0 pF, the rising time and the inspection pulse signal The fall time almost coincides with the input pulse signal.

  The A / D converter 98 samples the output potential from the inverter 97 at a timing when a predetermined time elapses after the pulse signal input to the inverter 96 rises. At this time, the smaller the total capacitance between the inspection terminals 59a to 59d and the common electrode 134, the faster the rise time of the pulse and the higher the sampled output potential. The capacitance measuring circuit 82a outputs a digital signal indicating the sampled output potential to the peeling determining unit 83 as a measurement result corresponding to the total value of the capacitance.

  Returning to FIG. 8 and FIG. 9, the peeling determination unit 83 determines how much the COF 50 is peeled from the actuator unit 21 based on the measurement result from the capacitance measuring circuit 82 a. Specifically, based on the measurement result from the capacitance measuring circuit 82a (total value of the capacitance between the inspection terminals 59a to 59d and the common electrode 134), the inspection terminals 59a to 59a peeled from the inspection land 137. The number 59d is determined. This determination is made for each of the four inspection terminals 59a to 59d arranged in the vicinity of each end portion with respect to the long side of the terminal arrangement region 50a. Specifically, when the total value of the capacitance between the four inspection terminals 59a to 59d and the common electrode 134 is 40 pF, the number of inspection terminals 59a to 59d peeled from the inspection land 137 is determined as 0, When the total capacitance value is 30 pF, it is determined that the number of the inspection terminals 59a to 59d peeled from the inspection land 137 is 1 (only the inspection terminal 59a is peeled). When the total capacitance value is 20 pF, the inspection land It is determined that the number of inspection terminals 59a to 59d peeled from 137 is 2 (only the inspection terminals 59a and 59a are peeled), and when the total capacitance is 10 pF, the number of inspection terminals 59a to 59d peeled from the inspection land 137 Is 3 (only the inspection terminals 59a to 59c are peeled), and when the total capacitance is 0 pF, the number of the inspection terminals 59a to 59d peeled from the inspection land 137 is 4 (all the inspection terminals). Determining terminal 59a~59c peeling) and.

  The communication unit 84 transmits the determination result of the peeling determination unit 83 to the control board 54. The communication destination of the communication unit 84 may be an inspection apparatus that inspects the inkjet head 1 in the manufacturing process of the inkjet head 1 described later.

  Next, the inspection process of the inkjet head 1 included in the manufacturing process of the inkjet head 1 will be described with reference to FIG. FIG. 12 is a process diagram showing an inspection process of the inkjet head 1. As shown in FIG. 12, the inspection process of the inkjet head 1 includes a fixing process, a joining process, a load test process, a measurement process, a determination process, and a management process. In the fixing step, the flow path unit 9 and the actuator unit 21 are fixed so that each pressure chamber 110 and the corresponding individual electrode 135 face each other (see FIG. 6). Thereafter, in the joining step, the output terminal 58 and the individual land 136 are joined on the joining surface of the actuator unit 21, the ground terminal 60 and the COM land are joined, and the inspection terminal 59a. The COF 50 is joined to the actuator unit 21 so that .about.59d and the inspection land 137 are joined (see FIG. 9). In this joining step, when joining the COF 50 to the actuator unit 21, various joining conditions such as a heating temperature, a heating time, and a pressing force determined in advance are applied.

  In the load test process, one inkjet head 1 that has completed the fixing process and the joining process is selected for each predetermined rod, and a load test is performed on the selected inkjet head 1. This load test is a thermal shock test in which the ambient temperature of the inkjet head 1 is rapidly changed, and a load is applied to the joint portion between the COF 50 and the actuator unit 21. In the thermal shock test, the temperature in the test layer is changed in a state where the inkjet head 1 is disposed in the gas phase test layer. For example, the temperature in the test layer is alternately changed between −40 ° C. and 100 ° C. for 30 minutes each. This is repeated for about 200 cycles. Note that a liquid test layer may be used instead of the gas phase test layer. According to this, the thermal shock test can be completed in a shorter time than the case where a gas phase test layer is used.

  At this time, an acceleration test in which the actuator unit 21 is driven at a high speed may be performed. In the acceleration test, the actuator unit 21 is driven with a voltage higher than the voltage when the actuator unit 21 is normally driven. The reliability of the joint between the COF 50 and the actuator unit 21 follows the Arrhenius rule, and the drive voltage of the actuator unit 21 increases, so that the amount of displacement of the actuator unit 21 increases. Thereby, the load concerning a junction part becomes larger. Further, the actuator unit 21 may be driven with a drive cycle shorter than the drive cycle when the actuator unit 21 is normally driven. Thereby, the frequency | count of the load per time given to a junction part can be increased. Furthermore, the time required for the accelerated test can be further shortened by setting the inside of the test layer to a high temperature and high humidity condition, for example, a temperature of 85 ° C. and a humidity of 85%. These conditions may be set by selecting the optimum one based on the life specified in the inkjet head 1 and the conditions for use.

  In the measurement process, the COF 50 of the inkjet head 1 that has undergone the load test process is connected to the connector 54a of the control board 54, and the capacitance measurement circuit 82a of the electrical characteristic measurement unit 82 includes the electrical characteristics of the inspection terminals 59a to 59d, That is, in this embodiment, as described above, the total value of the capacitance between the four test terminals 59a to 59d and the common electrode 134 is measured. Finally, in the determination step, the peeling determination unit 83 determines the number of inspection terminals 59a to 59d that have peeled from the inspection land 137 based on the measurement result from the capacitance measurement circuit 82a. Thereby, it can be grasped how much the COF 50 is peeled off from the actuator unit 21.

  In the management process, various bonding conditions applied in the above-described bonding process and the degree of peeling of the COF 50 from the actuator unit 21 are verified, and various bonding conditions in the bonding process related to the inkjet head 1 determined to be abnormal based on the verification result. Review.

  The measurement process and the determination process described above can be executed not only on the manufacturing process of the ink jet head 1 but also after being shipped as the ink jet head 1 or the ink jet printer 101 periodically or according to a user instruction. In this case, at the time of shipment, even if the COF 50 is completely joined to the actuator unit 21, it is detected that the COF 50 is gradually separated from the actuator unit 21 due to a change in temperature over time. be able to. Thus, the user can take measures such as requesting the manufacturer to repair before the ink droplets are no longer ejected from the inkjet head 1 when the COF 50 is completely separated from the actuator unit 21. In addition, in the manufacturing process of the inkjet head 1, an inspection apparatus including the above-described electrical characteristic measurement unit 82 and the peeling determination unit 83 may be separately prepared, and the measurement process and the determination process may be performed using this inspection apparatus. . In this case, the inkjet printer itself may be configured not to include the electrical characteristic measurement unit and the peeling determination unit.

  As described above, according to the present embodiment described above, the inspection terminals 59a to 59d separated from the inspection land 137 can be measured by a simple method of measuring the total capacitance between the inspection terminals 59a to 59d and the common electrode 134. By determining the number, it is possible to easily determine how much the COF 50 is separated from the actuator unit 21. Thereby, it becomes easy to adjust the joining conditions in the joining process when manufacturing the inkjet head 1, and the yield of the inkjet head 1 can be improved. In addition, even after the inkjet head 1 is manufactured, the inkjet head 1 can be inspected to easily determine whether or not the COF 50 may be detached from the actuator unit 21 and cause a failure. As a result, it is possible to take precautions such as replacement of the inkjet head 1 that may cause a failure.

  Moreover, since the electrical characteristic measurement part 82 should just measure the total value of the electrostatic capacitance between the test | inspection terminals 59a-59d and the common electrode 134, it can implement | achieve the electrical characteristic measurement part 82 with a simple circuit structure. it can.

  Four inspection terminals 59a to 59d are arranged in the order of inspection terminal 59a → inspection terminal 59b → inspection terminal 59c → inspection terminal 59d from the long side of the terminal arrangement region 50a along the direction opposite to the COF 50 drawing direction. Therefore, when the COF 50 is peeled from the actuator unit 21, the inspection terminals 59a to 59d are peeled from the inspection land 137 in the order of the inspection terminal 59a → the inspection terminal 59b → the inspection terminal 59c → the inspection terminal 59d. For this reason, by determining the number of inspection terminals 59a to 59d peeled from the inspection land 137, it is possible to accurately determine how much the COF 50 is peeled from the actuator unit 21.

  Further, a total of four inspection terminals 59a and 59b are arranged near both ends of the long side of the actuator unit 21 and at positions closer to the end of the COF 50 in the lead-out direction on the joint surface than the large number of individual electrodes 135. Therefore, the separation of the COF 50 from the actuator unit 21 can be efficiently suppressed.

  In this embodiment, the inspection land 137 is electrically connected to the common electrode 134, but the inspection land 137 is electrically connected to the flow path unit 9 that is a metal member. There may be. In this case, it is preferable that the ground potential is applied to the flow path unit 9 via a frame (not shown).

  In the present embodiment, the electrical characteristic measuring unit 82 is configured to measure the total value of the capacitance between the inspection terminals 59a to 59d and the common electrode 134. The structure which measures the electrostatic capacitance between the test | inspection terminals 59a-59d and the common electrode 134 separately may be sufficient. In this case, in the COF, the inspection terminals 59a to 59d need to be electrically independent from each other.

<Modification>
A modification according to the present embodiment will be described with reference to FIG. FIG. 13 is a partially enlarged plan view of the COF 50 in the present modification. As shown in FIG. 13, in the COF 50, the inspection wiring 73a connected to the inspection terminals 59a to 59d is connected to the output wiring 57a connected to the inspection individual electrode 135a that is the individual electrode 135 adjacent to the inspection terminals 59a to 59d. Has been. Thus, the inspection terminals 59a to 59d and the inspection individual electrode 135a are electrically connected. The capacitance measuring circuit 82a measures the total value of each capacitance between the common electrode 134 and the inspection terminals 59a to 59d and between the common electrode 134 and the inspection individual electrode 135a. The inverter 96 of the capacitance measuring circuit 82a uses a part of the drive circuit for outputting a drive signal to the inspection individual electrode 135a.

  According to this modification, a part of the drive circuit for outputting a drive signal to the inspection individual electrode 135a is used, so that the circuit scale of the driver IC 52 can be suppressed from increasing.

  In this modification, the drive circuit for outputting the drive signal to the inspection individual electrode 135a has the same driving characteristics of the actuator unit 21 corresponding to each individual electrode 135 including the inspection individual electrode 135a. The current value of the drive signal output to the individual electrode 135a is preferably configured to be larger than the current value of the drive signal output to the other individual electrode 135 excluding the inspection individual electrode 135a. Specifically, in order to output a drive signal to the inspection individual electrode 135a, the ON resistance of the transistor of the drive circuit is made smaller than those of other drive circuits. According to this, variation in the drive characteristics of the actuator unit 21 can be suppressed.

Second Embodiment
Next, an ink jet printer according to a second embodiment of the present invention will be described with reference to FIGS. In addition, about the member and function part which are substantially the same as 1st Embodiment, the code | symbol same as 1st Embodiment is attached | subjected and description is abbreviate | omitted. FIG. 14 is a functional block diagram of the driver IC 152 included in the inkjet printer according to the second embodiment. FIG. 15 is a diagram for explaining the positional relationship between the inspection terminal 59a and the common electrode 134. FIG. FIG. 15A is a partially enlarged plan view of the COF 150 and the actuator unit 21. FIG. 15B is a partial cross-sectional view of the COF 150 and the actuator unit 21 when the COF 150 is not peeled from the actuator unit 21. FIG. 15C is a partial cross-sectional view of the COF 150 and the actuator unit 21 when the COF 150 is peeled from the actuator unit 21. In FIG. 15B and FIG. 15C, only the inspection terminal 59a among the four inspection terminals 59a to 59d appears. As illustrated in FIG. 14, the driver IC 152 includes a drive signal output unit 81, an electrical characteristic measurement unit (measurement unit) 182, a peeling determination unit (determination unit) 183, and a communication unit 84.

  As shown in FIGS. 14 and 15A, the COF 150 is formed with inspection wirings 173 connected to the corresponding inspection terminals 59a to 59d. Each inspection wiring 173 is independently connected to the driver IC 152.

  As shown in FIGS. 15A and 15B, the piezoelectric sheet 141 is formed with an internal wiring 134a that connects the common electrode 134 and the inspection land 137 while penetrating the piezoelectric sheet 141 in the thickness direction. Yes. Therefore, when the COF 150 is not separated from the actuator unit 21, the inspection terminal 59a and the common electrode 134 are electrically connected via the inspection land 137 and the internal wiring 134a, and the inspection terminal 59a and the common electrode 134 are connected. The resistance value between is about 0.1Ω. As shown in FIG. 15C, when the inspection terminal 59a is peeled from the inspection land 137, the resistance value between the inspection terminal 59a and the common electrode 134 becomes ∞Ω. When the COF 150 is peeled off from the actuator unit 21, the four inspection terminals 59a to 59d are arranged in order from the wiring region 50b side, specifically, in the order of the inspection terminal 59a → the inspection terminal 59b → the inspection terminal 59c → the inspection terminal 59d. It is peeled from the inspection land 137. As described above, the number of test terminals 59a to 59d having a resistance value of ∞Ω with respect to the common electrode 134 varies depending on the degree of separation of the COF 50 from the actuator unit 21 (see FIG. 10).

  The electrical characteristic measurement unit 182 measures electrical characteristics of the inspection terminals 59a to 59d, and includes a resistance measurement circuit 182a. The resistance measurement circuit 182a measures the resistance value between the test terminals 59a to 59d and the common electrode 134 as the electrical characteristics of the test terminals 59a to 59d. The resistance measurement circuit 182a will be described with further reference to FIG.

  FIG. 16 is a schematic circuit diagram showing the internal configuration of the resistance measurement circuit 182a. In FIG. 16, only the circuit configuration for measuring the resistance value between the inspection terminal 59a and the common electrode 134 is shown. The circuit configuration for measuring the resistance value between the other inspection terminals 59b to 59d and the common electrode 134 is substantially the same as the circuit configuration shown in FIG. The resistance measurement circuit 182 a includes a pair of inverters 96 and 97 and a comparator 198. The inverter 96 outputs a test signal to the test terminal 59a via the drive resistor R1 when a continuous pulse signal is input. The inverter 97 outputs the inspection signal from the inverter 96 to the comparator 198. The comparator 198 compares the output potential from the inverter 97 with a high level reference voltage. As described above, when the COF 150 is not peeled from the actuator unit 21, that is, when the inspection terminal 59a is not peeled from the inspection land 137, the resistance value between the inspection terminal 59a and the common electrode 134 is 0. Since it is about 1Ω, the output potential of the inverter 96 is always low and the output potential of the inverter 97 is always high. On the other hand, when the inspection terminal 59a is peeled off from the inspection land 137, the resistance value between the inspection terminal 59a and the common electrode 134 is ∞Ω, so that the output potential of the inverter 96 is converted into a continuous pulse signal. In combination, the output potential of the inverter 97 changes between the high level and the low level.

  Therefore, the comparator 198 has a measurement result that the resistance value between the inspection terminal 59a and the common electrode 134 is about 0.1Ω when the output potential of the inverter 97 matches the reference voltage (both are high level). Is output to the peeling determination unit 183, and when the output of the inverter 97 does not coincide with the reference voltage, that is, when the output of the inverter 97 is at a low level even once, between the inspection terminal 59a and the common electrode 134 A measurement result with a resistance value of ∞Ω is output to the peeling determination unit 183. The electrical characteristic measuring unit 182 also measures the resistance value between each of the inspection terminals 59b to 59d with the common electrode 134 with the same configuration, and outputs the measurement result to the peeling determination unit 183.

  14 and 15, the peeling determination unit 183 determines how much the COF 50 is peeled from the actuator unit 21 based on the measurement result from the resistance measurement circuit 182a. Specifically, the number of inspection terminals 59a to 59d peeled from the inspection land 137 is determined based on the measurement result (resistance value) from the resistance measurement circuit 182a. That is, if the resistance value, which is the measurement result from the resistance measurement circuit 182a, is about 0.1Ω in each of the inspection terminals 59a to 59d, the separation determination unit 183 has separated the inspection terminals 59a to 59d from the inspection land 137. If the resistance value is ∞Ω, it is determined that the inspection terminals 59a to 59d are separated from the inspection land 137. Thereby, the number of inspection terminals 59a to 59d peeled from the inspection land 137 is determined.

  As described above, the case where the resistance value is ∞Ω has been described as the peeled state. However, when an external force is applied to the joint portion of the COF 150, the joint portion may be damaged to be in a partially peeled state. In this case, the resistance value becomes a high resistance state corresponding to the damaged state.

  The peeling determination unit 183 determines that the COF 150 has been peeled even when the joint is in such a high resistance state. As an example, it is assumed that the drive resistance R1 is 100Ω and the inverter 96 can pass a current of 10 mA at 24V. In this case, the threshold value of the inverter 97 is set to 2.5 V, and the presence or absence of peeling is determined. When the junction is in a good connection state (resistance value: about 0.1Ω), the output voltage of the inverter 97 is 1.001V. Since the threshold value of the inverter 97 is 2.5 V, the output of the inverter 97 is at a high level, and the separation determining unit 183 determines that the joint is not separated. On the other hand, when the junction is damaged and has a resistance value of 1 kΩ, the output voltage of the inverter 97 is 10V, which is higher than the threshold value of 2.5V. At this time, the output of the inverter 97 is at a low level, and the peeling determination unit 183 determines that the joint has been peeled off. In the case of this example, when the resistance of the joint becomes 150Ω or more, the peel determination unit 183 determines that the joint has peeled.

  Thus, the drive capability and drive resistance of the inverter 96 are determined by the drive characteristics of the actuator unit 21. By setting the resistance value corresponding to the operating voltage range and the peeled state, and determining the threshold value as described above, in addition to the complete peeled state, even in the middle of reaching that state, a bonding abnormality is detected. be able to.

  In addition, since the manufacturing method of the inkjet head which concerns on this embodiment is substantially the same as 1st Embodiment, description is abbreviate | omitted.

  As described above, according to the present embodiment, the number of inspection terminals 59a to 59d peeled from the inspection land 137 is determined by a simple method of measuring the resistance value between the inspection terminals 59a to 59d and the common electrode 134. By doing so, it is possible to easily determine how much the COF 150 is separated from the actuator unit 21. Thereby, it becomes easy to adjust the joining conditions in the joining process when manufacturing the inkjet head, and the yield of the inkjet head can be improved. Further, even after the ink jet head is manufactured, the ink jet head can be inspected to easily determine whether or not the COF 50 may be detached from the actuator unit 21 and cause a failure. As a result, it is possible to take precautions such as replacement of an inkjet head that may cause a failure.

<Third Embodiment>
Next, an ink jet printer according to a third embodiment of the present invention will be described with reference to FIG. In addition, about the member and function part which are substantially the same as 1st Embodiment, the code | symbol same as 1st Embodiment is attached | subjected and description is abbreviate | omitted. FIG. 17 is a functional block diagram of the driver IC 252 and the control board 254 included in the ink jet printer according to the third embodiment. As illustrated in FIG. 17, the driver IC 252 includes a drive signal output unit 81 and an inspection signal output unit 285. In addition, the control board 254 includes an electrical characteristic measurement unit (electrical characteristic measurement unit) 282 and a peeling determination unit (determination unit) 283.

  The inspection signal output unit 285 and the electrical characteristic measurement unit 282 will be described with reference to FIG. FIG. 18 is a schematic circuit diagram showing the internal configuration of the inspection signal output unit 285 and the electrical characteristic measurement unit 282. As shown in FIG. 18, the inspection signal output unit 285 has an inverter 296 that outputs an inspection pulse signal for each of the four inspection terminals 59a to 59d in the COF 50 through the drive resistor R1 when a pulse signal is input. is doing. The electrical characteristic measuring unit 282 measures electrical characteristics of the inspection terminals 59a to 59d, and measures the power consumption of the inverter 296 when the inspection pulse signal (frequency F, voltage V) is output to the inspection terminals 59a to 59d. To do. In addition, the electrical characteristic measurement unit 282 outputs the measurement result to the peeling determination unit 283.

Returning to FIG. 17, the peeling determination unit 283 determines how much the COF 50 is peeled from the actuator unit 21 based on the measurement result (power consumption i of the inverter 296) from the electrical characteristic measurement unit 282, that is, the inspection land. The number of inspection terminals 59a to 59d peeled from 137 is determined. This determination is made for each of the four inspection terminals 59a to 59d arranged in the vicinity of each end portion with respect to the long side of the terminal arrangement region 50a. Inverter 296, the inspection terminals 59a to 59d, the frequency F, when outputting the test pulse signal of the voltage V, the power consumption i of the inverter 296 becomes i = FCV ^2. The peeling determination unit 283 calculates the capacitance C between the four inspection terminals 59a to 59d and the common electrode 134 from the power consumption i based on this equation. As described above, when the COF 50 is separated from the actuator unit 21 and the inspection terminals 59a to 59d are separated from the inspection land 137 in the order of the inspection terminal 59a → the inspection terminal 59b → the inspection terminal 59c → the inspection terminal 59d, The total value of the capacitance between the inspection terminals 59a to 59d and the common electrode 134 changes in the order of 30 pF → 20 pF → 10 pF → 0 pF (see FIGS. 9 and 10). Thereby, the peeling determination unit 283 can determine the number of inspection terminals 59a to 59d peeled from the inspection land 137 based on the calculated capacitance C.

  Also in this embodiment, in the same way as in the second embodiment described above, by setting a threshold value for the power consumption of the inverter 296 measured by the electrical characteristic measuring unit 282, in addition to the complete peeling state, the state Even in the middle of the process, it is possible to detect a bonding abnormality.

  In addition, since the manufacturing method of the inkjet head which concerns on this embodiment is substantially the same as 1st Embodiment, description is abbreviate | omitted.

  As described above, according to the present embodiment described above, by determining the number of inspection terminals 59a to 59d peeled from the inspection land 137 by a simple method of measuring the power consumption of the inverter 296, the COF 150 can be detected from the actuator unit 21. It is possible to easily determine whether or not the peeling has occurred. Thereby, it becomes easy to adjust the joining conditions in the joining process when manufacturing the inkjet head, and the yield of the inkjet head can be improved. Further, even after the ink jet head is manufactured, the ink jet head can be inspected to easily determine whether or not the COF 50 may be detached from the actuator unit 21 and cause a failure. As a result, it is possible to take precautions such as replacement of an inkjet head that may cause a failure.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, in the first and second embodiments described above, the four inspection terminals 59a to 59d are arranged along the direction opposite to the drawing direction of the COFs 50 and 150 from the long side of the terminal arrangement region 50a. The terminals 59b, the inspection terminals 59c, and the inspection terminals 59d are arranged in this order. However, the inspection terminals may be arranged at arbitrary positions as long as they are within the bonding region with the actuator unit 21 in the COFs 50 and 150. The number of inspection terminals may be any number as long as it is two or more.

  Further, in the first and second embodiments described above, the four inspection terminals 59a and 59b are in the vicinity of both ends of the long side of the actuator unit 21, and the COF 50 lead-out direction on the joint surface more than the large number of individual electrodes 135. Although it is the structure arrange | positioned in the position near the edge part of the side, as above-mentioned, each test | inspection terminal may be arrange | positioned in arbitrary positions.

  In addition, in the first embodiment described above, the inspection land 137 is formed on the surface of the piezoelectric sheet 141 of the actuator unit 21, and the inspection terminals 59a to 59d of the COF 50 are joined to the inspection land 137. However, the inspection terminals 59a to 59d may be directly bonded to the surface of the piezoelectric sheet 141 with an adhesive or the like.

  In the first embodiment described above, the electrical characteristic measuring unit 82 is configured to measure the total capacitance between the inspection terminals 59a to 59d and the common electrode 134, and the second embodiment described above. In the embodiment, the electrical characteristic measuring unit 182 is configured to measure the resistance value between each of the inspection terminals 59 a to 59 d and the common electrode 134, but the electrical characteristic measuring unit is configured to peel off from the inspection land 137. The configuration may be such that other electrical characteristics of the inspection terminals 59a to 59d that change depending on the presence or absence are measured.

  In the second embodiment described above, the state of the junction is determined from the resistance value between each of the inspection terminals 59a to 59d and the common electrode 134 by the combination of the two inverters 96 and 97. As in the embodiment, the state of the junction may be determined from the power consumption of the inverter. For example, as shown in FIG. 19, the inverter 296 is driven to output a high level to the inspection terminal 59 connected to the common electrode 134 via the internal wiring 134a. If the bonded portion is in a good bonded state, a direct current corresponding to the high level output also flows through the electrical characteristic measuring unit 282. If the bonded portion is in the peeled state, no current flows through the electrical property measuring unit 282. Further, if the joint is damaged, a current corresponding to the resistance value at each of the inspection terminals 59a to 59d flows. Even in this case, in the same way as in the above-described embodiment, by setting a threshold value for the power consumption of the inverter 296 measured by the electrical characteristic measuring unit 282, in addition to the complete peeling state, Even if it exists, abnormality of joining can be detected.

  In the first and second embodiments described above, an inkjet recording apparatus is configured as the inkjet printer 101. However, the inkjet recording apparatus may be configured as a single inkjet head 1.

1 is an external side view of an inkjet head according to a first embodiment of the present invention. It is sectional drawing along the transversal direction of the inkjet head shown in FIG. FIG. 3 is a plan view of the head main body shown in FIG. 2. It is an enlarged view of the area | region enclosed with the dashed-dotted line shown in FIG. It is the VV sectional view taken on the line shown in FIG. It is a figure for demonstrating the actuator unit shown in FIG. FIG. 3 is a plan view of the COF shown in FIG. 2. FIG. 3 is a functional block diagram of the driver IC shown in FIG. 2. It is a figure for demonstrating the positional relationship of the test | inspection terminal shown in FIG. 2, and a common electrode. It is a fragmentary sectional view regarding the XX line shown to Fig.9 (a) when COF peels from the actuator unit. It is a schematic circuit diagram which shows the internal structure of the electrostatic capacitance measurement circuit shown in FIG. It is process drawing which shows the test | inspection process of the inkjet head shown in FIG. It is the elements on larger scale of COF which is a modification. It is a functional block diagram of a driver IC according to a second embodiment of the present invention. It is a figure for demonstrating the positional relationship of the test | inspection terminal shown in FIG. 14, and a common electrode. It is a schematic circuit diagram which shows the internal structure of the resistance measurement circuit shown in FIG. FIG. 10 is a functional block diagram of a driver IC according to a third embodiment of the present invention. It is a schematic circuit diagram which shows the internal structure of the test | inspection signal output part shown in FIG. 17, and an electrical property measurement part. It is a schematic circuit diagram which shows the internal structure of the electrical property measurement part which is a modification of 3rd Embodiment of this invention.

Explanation of symbols

1 Inkjet head 21 Actuator unit 50, 150 COF
50a Terminal arrangement area 50b Wiring area 50c Terminal 54, 254 Control board 54a Connector 55 Head cover 57a Output wiring 57b Control wiring 58 Output terminals 59a-59d Inspection terminal 60 Ground terminal 72 COM pattern 73, 173 Inspection wiring 81 Drive signal output unit 82, 182, 282 Electrical characteristic measurement unit 82 a Capacitance measurement circuit 182 a Resistance measurement circuit 83, 183, 283 Separation determination unit 84 Communication unit 96, 97 Inverter 98 A / D converter 101 Inkjet printer 134 Common electrode 134 a Internal wiring 135 Individual electrode 136 Individual land 137 Inspection land 141-143 Piezoelectric sheet 198 Comparator 285 Inspection signal output unit 52, 152 Driver IC
R1 Drive resistance

Claims (11)

A flow path unit in which a plurality of individual ink flow paths reaching a nozzle through a pressure chamber are formed, a plurality of individual electrodes, a common electrode, a piezoelectric layer disposed between the plurality of individual electrodes and the common electrode, And a fixing step of fixing the actuator having a plurality of individual lands electrically connected to the plurality of individual electrodes so that the plurality of pressure chambers and the plurality of individual electrodes face each other,
A flat flexible substrate having a plurality of output terminals and a plurality of inspection terminals, so that the plurality of inspection terminals are bonded to a bonding surface on the opposite side of the flow path unit in the actuator, and A bonding step of bonding to the actuator such that the plurality of output terminals and the plurality of individual lands are bonded to each other;
A measuring step of measuring electrical characteristics of the plurality of inspection terminals in the flat flexible substrate bonded to the bonding surface of the actuator;
And a determination step of determining the number of inspection terminals peeled from the joint surface of the actuator based on the measurement result of the measurement step.   2. The method of manufacturing an ink jet head according to claim 1, wherein in the measuring step, capacitances between the common electrode and each inspection terminal are respectively measured. The inspection terminal and an inspection individual electrode that is one of the plurality of individual electrodes are electrically connected,
The total value of each electrostatic capacitance between the common electrode and the inspection terminal and between the common electrode and the inspection individual electrode is measured in the measurement step. Manufacturing method of the inkjet head. The actuator further includes an inspection land that is disposed on the joint surface and electrically connected to the common electrode;
In the joining step, the inspection terminal is joined to the joint surface of the actuator via the inspection land,
The method of manufacturing an ink jet head according to claim 1, wherein in the measuring step, a resistance value between the common electrode and each inspection terminal is measured. The flow path unit includes a metal member;
The actuator further includes an inspection land disposed on the joint surface;
In the fixing step, the actuator is fixed to the flow path unit so that the inspection land is electrically connected to the metal member,
In the joining step, the inspection terminal is joined to the joint surface of the actuator via the inspection land,
The method of manufacturing an ink jet head according to claim 1, wherein in the measuring step, a resistance value between the metal member and each inspection terminal is measured.   2. The method of manufacturing an ink jet head according to claim 1, wherein in the measuring step, electrical characteristics of the inspection terminal are measured based on a current consumption when an inspection signal is output to the inspection terminal. In the bonding step, the flat flexible substrate is bonded to the actuator such that the flat flexible substrate extends from the actuator toward one side,
The method of manufacturing an ink jet head according to claim 1, wherein the plurality of inspection terminals of the flat flexible substrate are arranged along the one side.   8. The method of manufacturing an inkjet head according to claim 7, wherein at least one of the plurality of inspection terminals of the flat flexible substrate is arranged on the one side of the plurality of output terminals.   The method of manufacturing an ink jet head according to claim 7, wherein the plurality of inspection terminals of the flat flexible substrate are arranged on both sides in a direction orthogonal to the one of the plurality of output terminals. . A flow path unit in which a plurality of individual ink flow paths reaching the nozzles via the pressure chambers are formed, and a plurality of individual electrodes and a common electrode fixed to the flow path unit and associated with the plurality of pressure chambers The piezoelectric layer disposed between the plurality of individual electrodes and the common electrode, and the plurality of individual electrodes are electrically connected to the bonding surface opposite to the fixed surface of the flow path unit. An actuator having a plurality of connected individual lands, a plurality of output terminals joined to the plurality of individual lands, and a flat flexible substrate having a plurality of inspection terminals joined to the joining surface of the actuator. An inkjet head inspection method comprising:
A measuring step for measuring electrical characteristics of the plurality of inspection terminals;
An inspection method for an ink jet head, comprising: a determination step of determining the number of the inspection terminals peeled from the joint surface of the actuator based on a measurement result of the measurement step. A flow path unit in which a plurality of individual ink flow paths reaching the nozzles via the pressure chambers are formed;
A plurality of individual electrodes fixed to the flow path unit and associated with the plurality of pressure chambers, a common electrode, a piezoelectric layer disposed between the plurality of individual electrodes and the common electrode, and An actuator having a plurality of individual lands electrically connected to the plurality of individual electrodes while being arranged on a joint surface opposite to the fixed surface with the flow path unit;
A flat flexible substrate having a plurality of output terminals bonded to the plurality of individual lands, and a plurality of inspection terminals bonded to the bonding surface of the actuator;
Measuring means for measuring electrical characteristics of the plurality of inspection terminals;
An inkjet recording apparatus comprising: a determination unit that determines the number of the inspection terminals peeled from the joint surface of the actuator based on a measurement result of the measurement unit.

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