JP2014136310A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer which divides multiple individual wiring lines to respectively connect the divided wiring lines with two long sides of a driver IC and inhibits the deterioration of the print quality due to a difference in signal characteristics between the two long sides.SOLUTION: A driver IC 62 includes: a rectangular IC body 70; multiple first terminals disposed along one long side 70a of the IC body 70; and multiple second terminals disposed along the other long side 70b of the IC body 70. Individual wiring lines 63 corresponding to nozzle groups 44k, 44m, from among the multiple individual wiring lines 63 formed on a COF 31, are connected with the first terminals. The individual wiring lines 63 corresponding to nozzle groups 44y, 44c are connected with the second terminals.

Description

  The present invention relates to an inkjet printer.

  The ink jet printer of Patent Document 1 includes an ink jet head including a piezoelectric actuator that ejects ink from a plurality of nozzles, and an FPC (wiring board) connected to the piezoelectric actuator. Two rectangular driver ICs for driving the piezoelectric actuator are mounted on the FPC. The FPC is provided corresponding to each of the plurality of nozzles, and has a plurality of contact portions joined to the piezoelectric actuator, and an input portion to which a signal from the control device is input.

  The driver IC is disposed between the input unit and the plurality of contact units. The rectangular driver IC has a plurality of input terminals arranged along the long side on the input unit side and a plurality of output terminals arranged along the long side on the contact unit side. The plurality of input terminals of the driver IC are connected to the input unit by a plurality of wires. The plurality of output terminals of the driver IC are connected to the plurality of contact portions by a plurality of wires (individual wires), respectively.

  The driver IC generates drive signals for the plurality of nozzles based on input signals from the control device that are input to the plurality of input terminals. Furthermore, the driver IC sends drive signals respectively generated for the plurality of nozzles to the piezoelectric actuator from the plurality of output terminals via the plurality of individual wires. As described above, in Patent Document 1, a plurality of input terminals to which signals are input from the control device are arranged on one long side of the driver IC, and a drive signal is output to the piezoelectric actuator on the other long side. A plurality of output terminals are arranged.

  Patent Document 2 discloses a flexible substrate on which a rectangular semiconductor chip is mounted. In Patent Document 2, wirings connected to output outer leads are drawn from both sides of two long sides of a semiconductor chip. In addition, the electrode of a liquid crystal panel is illustrated as a connection destination of an output outer lead.

Japanese Patent No. 4888475 JP 2008-177402 A (particularly FIG. 1)

  In recent years, for the purpose of improving the printing speed, etc., it has been required to increase the number of nozzles of the inkjet head, but in proportion to the increase in the number of nozzles, the number of individual wirings and contact portions on the wiring board is also increased. Will increase. In this regard, as in Patent Document 1, when a plurality of individual wires are connected only to terminals arranged on one long side of the driver IC, the driver IC becomes longer as the number of individual wires increases. .

  On the other hand, the input wiring connected to the input part of the wiring board is for inputting a common signal to a plurality of nozzles. Unlike the individual wiring, the number of input wirings increases the number of nozzles. However, it does not increase greatly. Therefore, there is a margin in the connection space of the wiring on the long side connected to the input unit. Therefore, as in Patent Document 2, it is preferable that a plurality of individual wirings that are output wirings are separately connected to the two long sides of the driver IC. However, the inventors of the present application differed in signal characteristics when the same drive signal was output between a terminal located on one long side and a terminal located on the other long side in a rectangular driver IC. It has been found that may occur. This is presumably because a difference occurs in the characteristics of the circuit elements in the driver IC between one long side and the other long side.

  This will be described in detail below. FIG. 12 is a diagram for explaining a characteristic difference between circuit elements between two long sides of the driver IC. The driver IC 100 includes a rectangular IC body 101 and circuit elements 102 housed in the IC body 101. FIG. 12 shows a plurality of circuit elements 102 connected to a plurality of terminals 103 arranged along the two long sides 101a and 101b of the IC body 101. In FIG. 12, the hatched portion in each circuit element 102 indicates one circuit pattern 102 a of the circuit element 102.

  A circuit pattern of a general semiconductor chip such as a driver IC is formed by the following process. First, a photoresist is applied to the surface of a silicon wafer. Next, the photoresist is irradiated with ultraviolet rays through a photomask on which a predetermined pattern is formed, and the pattern is transferred to the photoresist. Further, the exposed portion of the photoresist is removed to form a resist pattern, and the wafer surface is etched using this resist pattern as a mask. As a result, a circuit pattern corresponding to the photomask pattern 102a is formed on the wafer.

  In the formation of the circuit pattern described above, when the photomask is placed at the correct position with respect to the wafer, the circuit pattern 102a is located in the circuit element 102 in all the circuit elements 102 as shown in FIG. Are formed at the same position. In this case, the circuit element 102 on the upper long side 101a side in the figure and the circuit element 102 on the lower long side 101b side in the figure are in a point-symmetrical relationship rotated by 180 degrees. The position of the circuit pattern 102a in FIG. 6 (for example, the relative position with respect to the terminal 103) is the same, and the circuit characteristics of all the circuit elements 102 are equal.

  However, it is conceivable that the position of the photomask is slightly shifted with respect to the wafer. FIG. 12B shows a case where the position of the photomask during pattern transfer is shifted in a direction A parallel to the wafer surface with respect to the normal position. At this time, in the upper circuit element 102, the circuit pattern 102 a is shifted in a direction approaching the terminal 103. On the other hand, in the lower circuit element 102, the circuit pattern 102a is shifted in the direction away from the terminal 103. That is, the position of the circuit pattern 102a in the circuit element 102 is different between the circuit element 102 on the long side 101a side and the circuit element 102 on the long side 101b side, and the circuit characteristics are also different.

  As can be seen from FIG. 12, when the photomask is displaced in a direction parallel to the wafer surface, the circuit elements 102 (upper side) arranged along the same long side 101a (or long side 101b) are aligned. Between the circuit elements 102 and between the lower circuit elements 102), the positions of the circuit patterns 102a are equal. However, when the photomask is rotated in a plane parallel to the surface of the wafer, the position of the circuit pattern 102a in the circuit element 102 is shifted between the circuit elements 102 arranged along the same long side. However, the shift due to the rotation of the photomask similarly occurs between the circuit elements 102 having different long sides. From the above, compared with the circuit elements 102 arranged along the same long side, the characteristic difference between the circuit elements 102 tends to be large between the circuit elements 102 arranged on different long sides.

  When the driver IC as shown in FIG. 12B is used in the ink jet printer, the drive signal output from the terminal on the long side 101a side and the drive signal output from the terminal on the long side 101b side. Thus, a difference occurs in the signal characteristics. The signal characteristic difference of the drive signal appears as, for example, signal waveform distortion or amplitude change. As a result, a difference occurs in the amount of ink droplets to be ejected and the ejection speed of the droplets among the plurality of nozzles, thereby degrading the print quality.

  An object of the present invention is to suppress a decrease in print quality due to a difference in signal characteristics between two long sides of a driver IC while connecting a plurality of individual wires separately to the two long sides of the driver IC. It is to provide an inkjet printer.

An ink jet printer according to a first aspect of the present invention is a wiring member in which a plurality of nozzles, a plurality of driving elements that respectively eject ink from the plurality of nozzles, and a plurality of individual wirings connected to the plurality of driving elements are formed. And an ink-jet head that is provided on the wiring member and outputs a driving signal to each of the plurality of driving elements via the individual wiring, and the plurality of nozzles eject ink. Are divided into multiple nozzle groups according to the type of
The driver IC includes a rectangular IC body, a plurality of first terminals disposed along one long side of the IC body, and a plurality of first terminals disposed along the other long side of the IC body. Of the plurality of individual wirings formed on the wiring member, the individual wiring corresponding to the first nozzle group included in the plurality of nozzle groups is connected to the first terminal, The individual wiring corresponding to the second nozzle group included in the plurality of nozzle groups is connected to the second terminal.

  In the present invention, the individual wirings respectively corresponding to different nozzle groups are divided and connected to the first terminal and the second terminal respectively disposed on the two long sides of the driver IC, thereby increasing the number of individual wirings. Even in this case, the length of the driver IC can be suppressed. Further, in the present invention, the allocation of the connection destination of the plurality of individual wirings to which of the first terminal and the second terminal is performed in units of nozzle groups. Therefore, between nozzles that eject the same type of ink, the connection destination of the individual wiring is a terminal arranged along the same long side of the IC body, and the signal characteristic difference of the drive signal is reduced. It should be noted that, since nozzles that discharge different types of ink have different connection destination terminals, there may be some characteristic differences in drive signals. However, between nozzles that eject different types of ink, compared to between nozzles that eject the same type of ink, even if there is a slight difference in the characteristics of the drive signal, it is less noticeable on the printed image, and the print quality is not reduced. It doesn't matter so much.

An ink jet printer according to a second aspect is the ink jet printer according to the first aspect, wherein the wiring member includes a connection portion connected to a control device that controls the driver IC, the plurality of individual wirings, and the plurality of driving elements. A plurality of drive contact portions connected to each other,
The driver IC is disposed between the connection portion and the plurality of drive contact portions so that the direction in which the connection portion and the plurality of drive contact portions are arranged and the long side of the IC body intersect. The plurality of first terminals are arranged along the long side of the IC body on the connection part side, and the plurality of second terminals are arranged along the long side of the plurality of drive contact parts side,
An individual wiring corresponding to the first nozzle group is connected to a part of the plurality of first terminals, and the connection portion and the driver IC are connected to the first terminal not connected to the individual wiring. A connection wiring to be connected is connected, an individual wiring corresponding to the second nozzle group is connected to a part of the plurality of second terminals, and the second terminal not connected to the individual wiring is connected to the second terminal A wiring different from the individual wiring and the connection wiring is connected.

  In the present invention, the driver IC is disposed between the connection portion with the control device and the plurality of drive contact portions. An individual wiring corresponding to the first nozzle group is connected to the first terminal disposed along the long side on the connection portion side of the driver IC, and the second terminal disposed along the long side on the drive contact portion side. Individual wirings corresponding to the second nozzle group are connected to the terminals. In addition, a connection wiring that connects the driver IC and the connection unit is connected to the first terminal on the connection unit side. On the other hand, in the long side second terminals on the side of the plurality of drive contact portions, there is a margin in the terminals because the connection wiring is not connected. Therefore, another wiring that is neither an individual wiring nor a connection wiring is connected to the second terminal.

  In the ink jet printer according to a third aspect of the present invention, in the second aspect of the present invention, the another wiring connects the constant potential portion of the driver IC and a common electrode provided in common to the plurality of driving elements. This wiring is characterized in that it is a wiring to be used.

  The potential of the common electrode is maintained at a predetermined reference potential by connecting the constant potential portion of the driver IC and the common electrode of the plurality of drive elements by the separate wiring connected to the second terminal.

  In the ink jet printer according to a fourth aspect of the present invention, in the second aspect of the present invention, the two driver ICs are disposed on the wiring member such that the plurality of second terminals face each other across the plurality of driving contact portions. The another wiring provided is a constant potential wiring that connects the constant potential portions of the two driver ICs.

  The constant potential portions connected to the second terminals of the two driver ICs make the constant potential portions of the two driver ICs conductive with each other, thereby stabilizing the reference potential of each driver IC. Since the two driver ICs are arranged so as to sandwich the plurality of drive contact portions, the constant potential wiring connecting the two driver ICs extends from each driver IC to the plurality of drive contact portion sides. . By the way, in the present invention, the individual wiring is also connected to the first terminal on the connection side, and this individual wiring bypasses the side of the driver IC and is located on the side opposite to the driver IC. Connected to. Therefore, when the constant potential wiring is connected to the first terminal on the connection portion side, for example, the surface of the wiring member opposite to the surface on which the individual wiring is formed is not interfered with the individual wiring. It is necessary to devise such as passing through or detouring larger than the individual wiring. In this regard, the constant potential wiring is connected to the second terminal on the drive contact portion side, so that the constant potential wiring can be easily routed.

An ink jet printer according to a fifth aspect is the ink jet printer according to the fourth aspect, wherein the ink jet head has an ink ejection surface on which the plurality of nozzles are formed, and the plurality of nozzle groups are parallel to the ink ejection surface. Arranged in a predetermined direction, the plurality of driving elements are arranged corresponding to the plurality of nozzles in a plane parallel to the ink ejection surface,
The wiring member is installed so as to cover the plurality of piezoelectric elements, the plurality of driving contact portions are arranged corresponding to the plurality of driving elements, and the two driver ICs have the long sides Arranged in a posture along the predetermined direction so as to sandwich the plurality of drive contact portions,
A cap member mounted on the ink discharge surface of the inkjet head so as to cover the plurality of nozzles, the cap member including a third nozzle group and the third nozzle of the plurality of nozzle groups; Two cap parts individually covering a fourth nozzle group adjacent to the group, and a partition part separating the two cap parts, and the partition part when the cap member is mounted on the inkjet head Is in contact with a region where the nozzles are not formed between the third nozzle group and the fourth nozzle group on the ink ejection surface,
The constant potential wiring connecting the two driver ICs of the wiring member includes an arrangement region of the driving contact portion corresponding to the third nozzle group and an arrangement region of the driving contact portion corresponding to the fourth nozzle group. It is characterized by passing between.

  In the present invention, as a premise, a plurality of piezoelectric elements are arranged in a plane corresponding to the plurality of nozzles, and a wiring member is installed so as to cover the plurality of piezoelectric elements. The cap member mounted on the ink ejection surface of the inkjet head has two cap portions that individually cover the adjacent third nozzle group and fourth nozzle group, and a partition wall portion that separates the two cap portions. In addition, when the cap member is mounted on the ink ejection surface, the partition wall portion that contacts the ink ejection surface does not interfere with the nozzles, and between the first nozzle group and the second nozzle group on the ink ejection surface, An area where no nozzle is formed is provided.

  On the other hand, in the wiring member, a plurality of driving contact portions are arranged corresponding to a plurality of nozzles (a plurality of piezoelectric elements) on the ink ejection surface. As described above, since there is a region where no nozzle is formed between the first nozzle group and the second nozzle group, the arrangement region of the drive contact portion corresponding to the first nozzle group of the wiring member, and the second There is also an area where the drive contact portion is not arranged between the arrangement areas of the drive contact portions corresponding to the nozzle group. Therefore, in the present invention, a region having no wiring member is effectively used by arranging a constant potential wiring connecting two driver ICs in a region where the driving contact portion is not disposed.

  According to the present invention, the individual wirings corresponding to the different nozzle groups are divided and connected to the first terminal and the second terminal respectively disposed on the two long sides of the driver IC, so that the number of the individual wirings is increased. Even when there are many, it can suppress the lengthening of a driver IC. Further, the distribution of the connection destinations of the plurality of individual wires to the first terminal or the second terminal is performed in units of nozzle groups. Therefore, between nozzles that eject the same type of ink, the connection destination of the individual wiring is a terminal arranged along the same long side of the IC body, and the signal characteristic difference of the drive signal is reduced. Accordingly, a decrease in print quality is suppressed.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment. FIG. 2 is a block diagram schematically illustrating an electrical configuration of a printer. It is the side view seen from the conveyance direction downstream side of the carriage when the inkjet head is in the capping state. It is a perspective view of an inkjet head. It is a top view of a head body. (A) is the A section enlarged view of FIG. 5, (b) is the BB sectional drawing of (a). It is a top view of COF. It is a top view of driver IC. It is a top view of driver IC concerning a change form. It is a top view of driver IC concerning another modification. It is a top view of COF which concerns on another modification. It is a figure explaining the characteristic difference of the circuit element between two long sides of driver IC.

  Next, an embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of an ink jet printer according to the present embodiment. FIG. 2 is a block diagram schematically showing the electrical configuration of the printer. As shown in FIG. 1, an inkjet printer 1 (hereinafter also simply referred to as printer 1) includes a platen 2, a carriage 3, an inkjet head 4, a holder 5, a paper feed roller 6, a paper discharge roller 7, a cap member 8, and a suction pump. 9. A control device 10 (see FIG. 2) is provided. In the following, the front side in FIG. 1 is defined as the upper side, and the other side of the page is defined as the lower side, and the explanation will be made using direction words “up” and “down” as appropriate.

  On the upper surface of the platen 2, a recording paper P that is a recording medium is placed. Above the platen 2, two guide rails 11 and 12 extending in parallel with the left-right direction (scanning direction) in FIG. 1 are provided. The carriage 3 is attached to the two guide rails 11 and 12, and is movable in the scanning direction along the two guide rails 11 and 12 in a region facing the platen 2. An endless drive belt 13 is attached to the carriage 3. When the drive belt 13 is driven by the carriage drive motor 14, the carriage 3 reciprocates in the scanning direction.

  The inkjet head 4 is attached to the lower part of the carriage 3 and moves in the scanning direction together with the carriage 3. A plurality of nozzles 43 are formed on the lower surface of the inkjet head 4 that is the surface on the opposite side of the paper surface of FIG. The plurality of nozzles 43 are divided into four nozzle groups 44 (44k, 44y, 44c, 44m) respectively corresponding to inks of four colors (black, yellow, cyan, magenta). The four nozzle groups 44 are arranged along the scanning direction in the order of black (K), yellow (Y), cyan (C), and magenta (M) from the left side of FIG. In the following description, “k”, “y”, “c”, and “m” after the reference numerals indicating the respective components are components corresponding to black, yellow, cyan, and magenta, respectively. Indicates. The specific configuration of the inkjet head 4 will be described in detail later.

  The holder 5 is mounted with four ink cartridges 15 each storing four color inks. The inkjet head 4 mounted on the carriage 3 and the holder 5 are connected by a tube (not shown). The four colors of ink stored in the four ink cartridges 15 are supplied to the inkjet head 4 through the tubes. The inkjet head 4 ejects four colors of ink from the four nozzle groups 44 to the recording paper P placed on the platen 2.

  The paper feed roller 6 and the paper discharge roller 7 are rotationally driven in synchronization by the conveyance motor 16 shown in FIG. The paper feed roller 6 and the paper discharge roller 7 cooperate to transport the recording paper placed on the platen 2 in the transport direction shown in FIG.

  The cap member 8 is disposed at a position on the one side in the scanning direction (the right side in FIG. 1) from the platen 2. When the carriage 3 moves to the right side of the platen 2, the cap member 8 faces the lower surface of the inkjet head 4. Further, the cap member 8 is driven up and down in the vertical direction (perpendicular to the plane of FIG. 1) by the cap drive motor 17 shown in FIG.

  FIG. 3 is a side view of the carriage viewed from the downstream side in the transport direction when the inkjet head is in the capping state. In FIG. 3, only the cap member 8 is shown in cross section. The cap member 8 includes a first cap portion 8a corresponding to the black nozzle group 44k and a second cap portion 8b corresponding to the three color (cyan, magenta, yellow) color nozzle groups 44y, 44c, and 44m. . The first cap portion 8a and the second cap portion 8b are separated by a partition wall portion 8c. When the cap member 8 is driven by the cap drive motor 17 and moves upward in a state where the cap member 8 faces the inkjet head 4, the cap member 8 covers the plurality of nozzles 43 so as to cover the plurality of nozzles 43. It is in close contact with the lower surface (ink ejection surface 4a). At this time, the first cap portion 8a covers the black nozzle group 44k, and the second cap portion 8b covers the three color nozzle groups 44y, 44c, and 44m (capping). As described above, the main reason why the cap portions 8a and 8b are divided between the black nozzle group 44k and the color nozzle groups 44y, 44c, and 44m is to eject the black ink nozzle 43 and the three color inks. This is to prevent ink color mixing with the nozzles 43 to be used.

  The suction pump 9 is connected to the cap member 8 via the switching device 18. The switching device 18 switches the connection destination of the suction pump 9 between the first cap portion 8a and the second cap portion 8b. When the suction pump 9 is driven while the cap member 8 is attached to the inkjet head 4, the inside of the cap portion 8 a (8 b) connected to the suction pump 9 is decompressed. At this time, the dust and bubbles in the inkjet head 4 or the ink having increased viscosity is discharged from the nozzle 43 covered with the pressure-reduced cap portion 8a (8b) (suction purge). The switching device 18 switches the connection destination of the suction pump 9 between the first cap portion 8a and the second cap portion 8b, whereby the black ink nozzle group 44k and the color ink three nozzle groups 44y, 44c, It is possible to select which of 44 m is subjected to suction purge.

  The control device 10 shown in FIG. 2 governs overall control of the inkjet head 4. The control device 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit) including various control circuits, and the like. As shown in FIG. 2, the control device 10 is connected to various devices or drive units of the printer 1 such as a driver IC 62 (described later) of the inkjet head 4, a carriage drive motor 14, and a carry motor 16. The control device 10 is connected to an operation panel 19 of the printer 1 and a PC 20 that is an external device.

  The control device 10 executes various processes by the CPU and ASIC according to the program stored in the ROM. That is, the control device 10 controls the driver IC 62 of the inkjet head 4, the carriage drive motor 14, and the like based on the print command transmitted from the PC 20 to print an image or the like on the recording paper P. Specifically, an ink discharge operation for discharging ink while moving the inkjet head 4 in the scanning direction together with the carriage 3, and a transport operation for transporting the recording paper P by a predetermined amount in the transport direction by the paper feed roller 6 and the paper discharge roller 7 And alternately. In addition, the control device 10 controls the switching device 18 and the suction pump 9 to execute the suction purge.

  Next, the configuration of the inkjet head 4 will be described in detail. FIG. 4 is a perspective view of the inkjet head. As shown in FIG. 4, the inkjet head 4 includes a head body 30, a COF (Chip On Film) 31, an FPC (Flexible Printed Circuit) 32, and the like.

  First, the head body 30 will be described. FIG. 5 is a plan view of the head body. 6A is an enlarged view of a portion A in FIG. 5, and FIG. 6B is a cross-sectional view taken along line BB in FIG. As shown in FIGS. 4 to 6, the head body 30 includes a flow path unit 33 and a piezoelectric actuator 34.

  As shown in FIG. 6B, the flow path unit 33 has a structure in which four plates 35 to 38 are stacked. The lowermost plate 38 of the four plates 35 to 38 is a nozzle plate 38 in which a plurality of nozzles 43 are formed. On the other hand, the remaining three plates 35 to 37 on the upper side are formed with flow paths such as a manifold 46 and a pressure chamber 47 communicating with the plurality of nozzles 43.

  As shown in FIGS. 4 and 5, four ink supply holes 45 are formed in the upper surface of the flow path unit 33 side by side in the scanning direction. Further, as shown in FIGS. 5 and 6, the flow path unit 33 has four manifolds 46 extending in the conveyance direction, respectively. The four manifolds 46 are connected to the four ink supply holes 45. The four color inks stored in the four ink cartridges 15 of the holder 5 are respectively supplied from the four ink supply holes 45 to the four manifolds 46.

  The flow path unit 33 includes a plurality of nozzles 43 and a plurality of pressure chambers 47 respectively corresponding to the plurality of nozzles 43. As shown in FIG. 6, the plurality of nozzles 43 are formed in the lowermost nozzle plate 38 so as to open downward. That is, the lower surface of the flow path unit (nozzle plate 38) is an ink ejection surface 4a on which a plurality of nozzles 43 are formed. The plurality of nozzles 43 are divided into four nozzle groups 44k, 44y, 44c, and 44m that respectively eject four colors of ink. Each nozzle group 44 includes two nozzle rows arranged in a staggered manner with the corresponding manifold 46 interposed therebetween. The four nozzle groups 44k, 44y, 44c, and 44m are arranged in the scanning direction parallel to the ink ejection surface 4a in the order of black, yellow, cyan, and magenta from the left side of the drawing.

  The plurality of pressure chambers 47 are formed in the plate 35 located in the uppermost layer of the flow path unit 33 and are arranged in a plane corresponding to the plurality of nozzles 43, respectively. As shown in FIG. 6A, the pressure chambers 47 are arranged in two rows in a staggered manner along the manifold 46 extending in the transport direction corresponding to the two nozzle rows of each nozzle group 44. . As shown in FIG. 6B, each pressure chamber 47 communicates with a corresponding manifold 46. As described above, as indicated by arrows in FIG. 6B, a plurality of individual flow paths are formed in the flow path unit 33, branching from the manifolds 46 and reaching the nozzles 43 via the pressure chambers 47.

  As shown in FIG. 5, on the ink ejection surface 4a of the inkjet head 4, there are three nozzle groups 44y, 44c between the black nozzle group 44k and the three color nozzle groups 44y, 44c, 44m. , 44m is wider than the distance between them. That is, there is a region where the nozzle 43 is not formed between the black nozzle group 44k and the color nozzle groups 44y, 44c, 44m. Accordingly, as shown in FIG. 3, when capping, the partition wall portion 8c of the cap member 8 causes the black ink nozzle group 44k and the three color ink nozzle groups 44y and 44c on the ink discharge surface 4a. , 44m, abuts on a region where the nozzle 43 is not formed. Therefore, the partition wall portion 8 c of the cap member 8 does not interfere with the nozzle 43.

  As shown in FIGS. 5 and 6, the piezoelectric actuator 34 includes a diaphragm 50, piezoelectric layers 54 and 55, a plurality of individual electrodes 52, and a common electrode 56. The vibration plate 50 is a plate made of a metal material such as stainless steel, for example, and is joined to the upper surface of the flow path unit 33 so as to cover the plurality of pressure chambers 47 in common. The two piezoelectric layers 54 and 55 are made of a piezoelectric material mainly composed of lead zirconate titanate (PZT), which is a solid solution of lead titanate and lead zirconate and is a ferroelectric substance. Are stacked.

  The plurality of individual electrodes 52 are disposed on the upper surface of the upper piezoelectric layer 55 so as to face the central portions of the plurality of pressure chambers 47, respectively. A plurality of connection terminals 57 are drawn from both ends of the manifold 46 along the longitudinal direction of the individual electrodes 52 from the end portions of the plurality of individual electrodes 52. The plurality of connection terminals 57 are respectively connected to the plurality of drive contact portions 60 of the COF 31 (see also FIG. 7). The common electrode 56 is formed almost entirely between the two piezoelectric layers 54 and 55 and faces the plurality of pressure chambers 47 in common. Although not shown, a connection terminal (not shown) is drawn from the common electrode 56 to the upper surface of the piezoelectric layer 55, and the connection terminal for the common electrode 56 is connected to the ground electrode pattern 64 of the COF 31 (see FIG. 7). The Thereby, the potential of the common electrode 56 is always held at the ground potential.

  The portion of the upper piezoelectric layer 55 sandwiched between the individual electrode 52 and the common electrode 56 is previously polarized in the thickness direction of the piezoelectric layer 55. This portion is a portion where piezoelectric deformation occurs when a potential difference is generated between the individual electrode 52 and the common electrode 56. Hereinafter, this portion is referred to as a “piezoelectric element 58”, and this piezoelectric element 58 is the driving element of the present invention. Equivalent to. In the present embodiment, a plurality of piezoelectric elements 58 respectively corresponding to the plurality of pressure chambers 47 are arranged in a plane along a plane parallel to the ink ejection surface 4a.

  FIG. 7 is a plan view of the COF. The COF 31 (wiring member) is made of a flexible material such as polyimide, and has an elongated shape in one direction (vertical direction in FIG. 7). The COF 31 has a plurality of drive contact portions 60 disposed at the center in the longitudinal direction, and two connection portions 61 provided at both ends in the longitudinal direction. Two driver ICs 62a and 62b are mounted at positions where the plurality of drive contact portions 60 are sandwiched in the longitudinal direction of the COF 31, respectively. Each driver IC 62 is connected to approximately half of the drive contact portions 60 associated in advance among the plurality of drive contact portions 60 by individual wiring 63.

  With the central portion of the COF 31 in the longitudinal direction covering the plurality of piezoelectric elements 58 of the piezoelectric actuator 34, the plurality of drive contact portions 60 and the connection terminals 57 of the plurality of piezoelectric elements 58 are joined. Further, as shown in FIG. 3, both end portions in the longitudinal direction of the COF 31 are folded upward, so that the COF 31 is formed in a substantially ring shape (C-shape opened upward). Note that both ends of the folded back COF 31 in the longitudinal direction are supported from below by support members 59 installed inside the ring-shaped COF 31. In addition, the FPC 32 is connected to the two connection portions 61 of the COF 31. The FPC 32 is connected to the control device 10 (see FIG. 2).

  The two driver ICs 62 generate and output a predetermined drive signal to each of the plurality of piezoelectric elements 58 based on the signal input from the control device 10. When a drive signal is output to a certain piezoelectric element 58, a potential difference is generated between the individual electrode 52 and the common electrode 56, an electric field acts on the piezoelectric element 58, and the direction thereof coincides with the polarization direction. Then, the piezoelectric element 58 contracts in the surface direction, and accordingly, the diaphragm 50 is bent. At this time, the volume of the pressure chamber 47 changes and a pressure wave is generated in the individual flow path including the pressure chamber 47, and ink is ejected from the nozzle 43.

  Two ground electrode patterns 64 are formed over the entire length of the COF 31 at both edges in the width direction of the COF 31. These two ground electrode patterns 64 are connected to the control device 10 via the FPC 32 and are always maintained at the ground potential. Further, when the COF 31 is joined to the piezoelectric actuator 34, the two ground electrode patterns 64 and the common electrode 56 of the piezoelectric actuator 34 are brought into conduction, whereby the common electrode 56 is held at the ground potential.

  The configurations of the COF 31 and the driver IC 62 will be described in more detail. As shown in FIG. 7, the two connection portions 61 of the COF 31 are connected to adjacent driver ICs 62 via a plurality of connection wirings 65. Thereby, the control device 10 and each driver IC 62 are connected via the FPC 32, the connection unit 61, and the connection wiring 65.

  As described above, the plurality of pressure chambers 47 are arranged corresponding to the plurality of nozzles 43, and the plurality of piezoelectric elements 58 facing the plurality of pressure chambers 47 are also arranged corresponding to the plurality of nozzles 43. Yes. Therefore, the plurality of driving contact portions 60 connected to the plurality of piezoelectric elements 58 (individual electrodes 52) are arranged in four contact groups 66 corresponding to the four nozzle groups 44, respectively. That is, as shown in FIG. 7, the plurality of drive contact portions 60 are arranged in the scanning direction from the left side in the drawing in the black contact group 66k, yellow contact group 66y, cyan contact group 66c, magenta. The contact group 66m is divided into four contact groups 66. Corresponding to the gap between the black nozzle group 44k and the three color nozzle groups 44y, 44c, 44m, the COF 31 has a black contact group 66k and a three color contact group 66y. , 66c, 66m, there is a vacant region where the drive contact portion 60 is not disposed.

  The plurality of drive contact portions 60 constituting each contact group 66 are connected to the driver IC 62 associated in advance among the two driver ICs 62 a and 62 b by the individual wiring 63. For example, half of the drive contact portions 60 in the black contact group 66 are assigned to one driver IC 62a, and the remaining half are assigned to the other driver IC 62b. A bundle of a plurality of individual wires 63 that connect one driver IC 62 and a plurality of drive contact portions 60 of one contact group 66 is referred to as an individual wire group 67. That is, one driver IC 62a (62b) and four contact groups 66 are connected by four individual wiring groups 67 (67k, 67y, 67c, 67m), respectively. In FIG. 7, for the sake of simplicity, the connection between the drive contact portion 60 and the corresponding individual wiring 63 in each contact group 66 is omitted except for a part thereof.

  FIG. 8 is a plan view of two driver ICs. Each driver IC 62 has a rectangular IC body 70. As shown in FIG. 7, each driver IC 62 includes four long contacts 70a and 70b of the IC body 70 between the connecting portion 61 and the plurality of driving contact portions 60 (four contact groups 66). The groups 66 are arranged in a posture along the width direction (scanning direction) of the COF 31 in which the groups 66 are arranged. The long sides 70a and 70b of the IC main body 70 do not have to be completely parallel to the width direction of the COF 31, and are slightly inclined with respect to the width direction (that is, at an angle other than 90 degrees with respect to the longitudinal direction of the COF 31). May be arranged).

  Each driver IC 62 includes a plurality of first terminals 71 arranged along the long side 70 a on the connection portion 61 side of the IC body 70 and a plurality of pieces arranged along the long side 70 b on the side of the plurality of driving contact portions 60. A second terminal 72 is provided. The shape and size of the IC body 70 are the same between the two driver ICs 62a and 62b, and the number of the first terminals 71 and the second terminals 72 is also the same. However, the two driver ICs 62a and 62b are mounted such that one of them is rotated 180 degrees in the plane of the COF 31 with respect to the other. Accordingly, as shown in FIG. 7, the two driver ICs 62a and 62b are arranged so that the second terminals 72 face each other across the plurality of drive contact portions 60.

  Each driver IC 62 is connected to the connection portion 61 and the plurality of drive contact portions 60 arranged so as to sandwich the driver IC 62 by wiring. As shown in FIG. 8, the plurality of connection wirings 65 extending from the connection part 61 are a group of first terminals (first terminals) located at the center of the long side 70a among the plurality of first terminals 71 on the connection part 61 side. 1 terminal group 73c). The connection wiring 65 includes a signal input line for inputting various control signals for causing the driver IC 62 to generate a drive signal, a voltage input line for a low voltage power source for control (for example, 3.3 V), and a drive for driving the piezoelectric actuator 34. A voltage input line of a high voltage power source (for example, 20V) and a ground input line are included. Each driver IC 62 generates a drive signal based on various signals input from the signal input line.

  Of the four individual wiring groups 67 respectively connected to the four contact groups 66, the black individual wiring group 67k and the magenta individual wiring group 67m bypass the side of the driver IC 62, respectively. It is connected to the first terminal 71 located on the connection part 61 side. More specifically, in the upper driver IC 62 of FIG. 7, the individual wiring 63k of the black individual wiring group 67k is a group of first terminals 71 located on the left end side of the first terminal 71 along the long side 70a. The individual wiring 63m of the magenta individual wiring group 67m is connected to a group of first terminals 71 (first terminal group 73b) located on the right end side in the drawing. . Further, in the driver IC 62b on the lower side of FIG. 7 arranged in a posture rotated 180 degrees with respect to the driver IC 62a, the assignment of black and magenta is reversed. That is, the individual wiring 63k of the black individual wiring group 67k is connected to the first terminal group 73b, and the individual wiring 63m of the magenta individual wiring group 67m is connected to the first terminal group 73a. The black nozzle group 44k and the magenta nozzle group 44m corresponding to the individual wiring groups 67k and 67m connected to the first terminal 71 correspond to the “first nozzle group” of the present invention.

  On the other hand, among the four individual wiring groups 67, the yellow individual wiring group 67y and the cyan individual wiring group 67c are connected to the second terminal 72 of the driver IC 62 located on the drive contact portion 60 side. More specifically, in the upper driver IC 62a of FIG. 7, the individual wiring 63y of the yellow individual wiring group 67y is a group of second terminals located on the left end side of the second terminal 72 along the long side 70b. The individual wiring 63c of the cyan individual wiring group 67c is connected to the terminal 72 (second terminal group 74a), and is connected to a group of second terminals 72 (second terminal group 74b) located on the right end side in the drawing. In the lower driver IC 62b of FIG. 7, the assignment of yellow and cyan is reversed, and the individual wiring 63y of the yellow individual wiring group 67y is connected to the second terminal group 74b, and the individual wiring group 67c of cyan is individually connected. The wiring 63c is connected to the second terminal group 74a. The yellow nozzle group 44y and the cyan nozzle group 44c corresponding to the individual wiring groups 67y and 67c connected to the second terminal 72 correspond to the “second nozzle group” of the present invention.

  As described above, the four individual wiring groups 67 respectively corresponding to the four nozzle groups 44 are the four terminal groups 73 a, 73 b, 74 a, and 74 b that are arranged firmly at the four corners of the rectangular IC body 70. Connected to each. Strictly speaking, in the present embodiment, the second terminal 72 connected to the yellow individual wiring group 67y is not located at the leftmost end (closest to the corner of the IC body 70). Of the plurality of second terminals 72, the second terminal 72d (72e) located at the leftmost end is connected to a constant potential wiring 68, which will be described later, different from the individual wiring 63, and connected to the yellow individual wiring group 67y. The second terminal group 74 is located on the right side of the leftmost second terminal 72d (72e).

  The driver IC 62 outputs a drive signal to each piezoelectric element 58 via the individual wiring 63. Here, as described above, the four individual wiring groups 67 respectively corresponding to the four nozzle groups 44 of different ink types are all arranged along the long side 70b on the drive contact portion 60 side. The first terminals 71 arranged along the long side 70a on the connection portion 61 side are also connected separately. Therefore, even when the number of the individual wirings 63 (that is, the number of nozzles 43) is large, the increase in the length of the driver IC 62 can be suppressed.

  In addition, the distribution of the connection destination of the plurality of individual wirings 63 to which of the first terminal 71 and the second terminal 72 is performed in units of individual wiring groups 66 corresponding to the nozzle group 44. Therefore, between the nozzles 43 that eject the same type of ink, the connection destination of the individual wiring 63 becomes a terminal arranged along the same long side 70a (70b) of the IC body 70, and the signal characteristic difference of the drive signal is different. Get smaller. In addition, between nozzles 43 that eject inks of different colors, the connection destination terminals of the individual wiring 63 are different, so that a slight characteristic difference may occur in the drive signal. However, between nozzles 43 that eject inks of different colors, compared to the nozzles 43 that eject inks of the same color, even if there is a slight difference in the characteristics of the drive signal, the print quality is not noticeable. The decline of is not a problem.

  In a general printer, the number of nozzles 43 is approximately equal among the four nozzle groups 44. FIG. 5 of the present embodiment shows a form in which the number of nozzles is all equal. Accordingly, the number of individual wirings 63 among the four individual wiring groups 67 corresponding to these four nozzle groups 44 is substantially equal. On the other hand, in addition to the individual wiring 63, a plurality of connection wirings 65 that connect the driver IC 62 and the connection part 61 are connected to the first terminal 71 on the connection part 61 side of the driver IC 62. Therefore, conversely, in the second terminal 72 on the driving contact portion 60 side, there is a margin in the terminal because the connection wiring 65 is not connected. Therefore, in the present embodiment, another wiring that is neither the individual wiring 63 nor the connection wiring 65 is connected to the second terminal 72 of the driver IC 62.

  As an example of the another wiring, in the present embodiment, a constant potential wiring 68 that connects the constant potential portions 75a and 75b of the two driver ICs 62 is cited. A ground input line 65 a, which is one of the connection wires 65 extending from the connection portion 61, is connected to one first terminal 71 of each driver IC 62. Each driver IC 62 has a constant potential portion 75 (75a, 75b) connected to the one first terminal 71 and maintaining a reference potential serving as a reference for the operation of the driver IC 62 at a ground potential. Have inside. The constant potential wirings 68 formed in the COF 31 cause the constant potential portions 75a and 75b of the two driver ICs 62 to conduct with each other, thereby stabilizing the reference potential (here, the ground potential) of each driver IC 62. Here, the constant potential wiring 68 connects the two driver ICs 62 by being connected to the second terminals 72 (72d, 72e) of the two driver ICs 62 on the drive contact portion 60 side.

  Further, as shown in FIG. 7, since the two driver ICs 62 are arranged so as to sandwich the plurality of drive contact portions 60, the constant potential wiring 68 that connects the two driver ICs 62 is connected to each of the driver ICs 62. It extends to the drive contact portion 60 side. Here, two individual wiring groups 67k and 67m are connected to the first terminal 71 on the connection portion 61 side of the driver IC 62, and these two individual wiring groups 67k and 67m bypass the side of the driver IC 62, respectively. The drive contact portion 60 located on the opposite side of the driver IC 62 is connected. Therefore, if the constant potential wiring 68 is connected to the first terminal 71 on the connection portion 61 side, for example, the individual wiring 63 of the COF 31 is formed so as not to interfere with the individual wiring 63 bypassing the driver IC 62. It is necessary to devise measures such as passing the surface opposite to the opposite surface (the surface on the back side in FIG. 7), or detouring larger than the individual wiring 63 if routing is performed within the same surface. In this respect, the constant potential wiring 68 is connected to the second terminal 72 on the drive contact portion 60 side, whereby the constant potential wiring 68 can be easily routed.

  In the present embodiment, the constant potential wiring 68 is connected to the second terminal 72 d (72 e) located at the leftmost end among the plurality of second terminals 72 of each driver IC 62. Further, as described above, the black contact point of the COF 31 corresponds to the gap between the black nozzle group 44k and the three color nozzle groups 44y, 44c, and 44m on the ink ejection surface 4a. Between the group 66k and the contact groups 66y, 66c, and 66m of the three colors, there is a vacant area where the drive contact portion 60 is not disposed. Therefore, the constant potential wiring 68 that connects the two driver ICs 62 is a driving contact portion between the arrangement region of the black contact group 66k and the arrangement region of the three color contact groups 66y, 66c, and 66m in the COF 31. It is formed so as to pass through a region where 60 is not disposed. Thereby, the vacant area of the COF 31 is effectively used. The black nozzle group 44k corresponds to the “third nozzle group” of the present invention, and the yellow nozzle group 44y adjacent to the black nozzle group 44k corresponds to the “fourth nozzle group” of the present invention.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] The connection configuration of the plurality of individual wirings 63 to the driver IC 62 is not limited to the configuration of the above embodiment.

  The individual wiring group 67 connected to the first terminal 71 of the driver IC 62 does not need to be divided on both sides of the driver IC 62 as shown in FIG. 7, and only one side of the driver IC 62 may be bypassed. .

  Further, it is not always necessary that the four individual wiring groups 67 are equally allocated between the first terminal 71 and the second terminal 72 of the driver IC 62. For example, in FIG. 9, only the connection wiring 65 to the connection portion 61 and the plurality of individual wirings 63k belonging to the black individual wiring group 67k are connected to the first terminal 71 on the long side 70a side of the driver IC 62. . On the other hand, the second terminal 72 on the long side 70b side of the driver IC 62 is connected to a plurality of individual wirings 63y, 63c, 63m belonging to the three color individual wiring groups 67y, 67c, 67m.

  Further, as shown in FIG. 7, the individual wiring 63 corresponding to one nozzle group 44 is not connected to the driver IC 62 as one bundle (one individual wiring group 67), but two or more bundles. And may be connected to the driver IC 62. For example, in FIG. 10, a plurality of individual wirings 63 corresponding to one nozzle group 44 are divided into two wiring groups and connected to the first terminal 71 or the second terminal 72 of the driver IC 62. However, even when the individual wirings 63 corresponding to one color ink are divided into two or more groups in this way, all the individual wirings 63 corresponding to the same color ink are all connected to the first terminal 71 and the second terminal. It is connected to either one of the terminals 72 and is not divided into the first terminal 71 and the second terminal 72. In the example of FIG. 10, the black individual wiring 63k1 located on the left side and the black individual wiring 63k2 located on the right side are both connected to the first terminal 71.

2] In the above embodiment, the black nozzle group 44k and the three color nozzle groups 44y, 44c, 44m are covered with the separate cap portions 8a, 8b of the cap member 8, and therefore, the COF 31 Between the black contact group 66k and the three color contact groups 66y, 66c and 66m, there is a region where the drive contact portion 60 is not formed. However, the number of cap portions of the cap member 8 and which cap portion covers which nozzle group 44 can be arbitrarily set according to the type of ink.

  For example, the cap member 8 may be provided with four cap portions that individually cover the four nozzle groups 44. In this case, a region for the partition wall portion 8c to contact is provided between the four nozzle groups 44 on the ink discharge surface 4a, and correspondingly, the drive contact portion is provided between the four contact groups 66 of the COF 31. Each vacant area where 60 is not formed is provided. In this case, the constant potential wiring 68 connecting the two driver ICs 62 can be arranged in an arbitrary region among the three regions existing between the four contact groups 66.

  Alternatively, the configuration may be such that the four nozzle groups 44 are commonly covered with one cap portion. However, in this case, since it is not necessary to secure a vacant area between the four nozzle groups 44, no vacant area is provided between the four contact groups 66. Therefore, when it is difficult to pass the constant potential wiring 68 across the arrangement region of the plurality of drive contact portions 60, it is necessary to devise such as passing the constant potential wiring 68 through the surface opposite to the COF 31.

3] In the above embodiment, an example in which two driver ICs 62 are mounted on the COF 31 is shown. However, the number of driver ICs 62 to be mounted is not limited to two, and may be one. There may be three or more.

4] In the above embodiment, the constant potential wiring 68 is exemplified as another wiring that is connected to the second terminal 72 of the driver IC 62 and is not the individual wiring 63 or the connection wiring 65. However, this other wiring is the constant potential wiring 68. It is not limited to. For example, in FIG. 11, the ground electrode pattern 64 connected to the common electrode 56 of the piezoelectric actuator 34 is formed between the black contact group 66k and the three color contact groups 66y, 66c, 66m. In addition, a wiring 69 that connects the ground electrode pattern 64 and the constant potential portion 75 in each driver IC 62 may be connected to the second terminal 72 of each driver IC 62. As a result, the potential of the common electrode 56 is held at a predetermined reference potential (the potential of the constant potential portion 75, here the ground potential). FIG. 11 shows an example in which two driver ICs 62 are mounted on the COF 31, but the present invention can be applied even if there is only one driver IC 62.

  In addition, wiring for transmitting and receiving signals other than the drive signal may be connected to the second terminal 72 of the driver IC 62. Examples of such wiring include wiring for receiving signals from various sensors provided in the piezoelectric actuator 34, wiring used for continuity inspection of the piezoelectric actuator 34, and the like.

5] In the above embodiment, an example in which the drive element that is a target for outputting a drive signal from the driver IC 62 via the individual wiring 63 is a piezoelectric element, but the drive element is not limited to a piezoelectric element. For example, a heating element that discharges droplets from the nozzles 43 by applying thermal energy to the ink may be used.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 4 Inkjet head 4a Ink discharge surface 8 Cap member 8a 1st cap part 8b 2nd cap part 8c Partition part 10 Control apparatus 31 COF
43 Nozzle 44 Nozzle group 56 Common electrode 58 Piezoelectric element 59 Support member 60 Driving contact portion 61 Connection portion 62 Driver IC
63 Individual wiring 65 Connection wiring 68 Constant potential wiring 69 Wiring 70 IC body 70a, 70b Long side 75a, 75b Constant potential section

Claims (5)

A plurality of nozzles, a plurality of drive elements that respectively eject ink from the plurality of nozzles, a wiring member that is formed with a plurality of individual wirings that are respectively connected to the plurality of drive elements, and provided in the previous wiring member, A driver IC that outputs a driving signal to each of the plurality of driving elements via the individual wiring;
The plurality of nozzles are divided into a plurality of nozzle groups according to the type of ink to be ejected,
The driver IC is
A rectangular IC body;
A plurality of first terminals arranged along one long side of the IC body;
A plurality of second terminals arranged along the other long side of the IC body,
Of the plurality of individual wires formed on the wiring member, an individual wire corresponding to a first nozzle group included in the plurality of nozzle groups is connected to the first terminal and included in the plurality of nozzle groups. An inkjet printer, wherein individual wirings corresponding to two nozzle groups are connected to the second terminal. The wiring member is
A connection unit connected to a control device for controlling the driver IC;
A plurality of driving contact portions respectively connecting the plurality of individual wirings and the plurality of driving elements;
The driver IC is disposed between the connection portion and the plurality of drive contact portions so that the direction in which the connection portion and the plurality of drive contact portions are arranged and the long side of the IC body intersect.
The plurality of first terminals are arranged along the long side of the IC body on the connection part side, and the plurality of second terminals are arranged along the long side of the plurality of drive contact parts side,
An individual wiring corresponding to the first nozzle group is connected to a part of the plurality of first terminals, and the connection portion and the driver IC are connected to the first terminal not connected to the individual wiring. Connection wiring to be connected is connected,
An individual wiring corresponding to the second nozzle group is connected to a part of the plurality of second terminals, and the second terminal that is not connected to the individual wiring includes the individual wiring and the connection wiring. The inkjet printer according to claim 1, wherein another wiring is connected.   The inkjet according to claim 2, wherein the another wiring is a wiring that connects a constant potential portion of the driver IC and a common electrode provided in common to the plurality of driving elements. Printer. The wiring member is provided with two driver ICs such that the plurality of second terminals face each other across the plurality of driving contact portions,
The inkjet printer according to claim 2, wherein the another wiring is a constant potential wiring that connects the constant potential portions of the two driver ICs. The inkjet head has an ink ejection surface on which the plurality of nozzles are formed,
The plurality of nozzle groups are arranged side by side in a predetermined direction parallel to the ink ejection surface,
The plurality of driving elements are respectively arranged corresponding to the plurality of nozzles in a plane parallel to the ink ejection surface,
The wiring member is installed so as to cover the plurality of piezoelectric elements, and the plurality of driving contact portions are arranged corresponding to the plurality of driving elements,
Further, the two driver ICs are arranged so that the long side is sandwiched between the plurality of driving contact portions in a posture along the predetermined direction.
A cap member mounted on the ink discharge surface of the inkjet head so as to cover the plurality of nozzles;
The cap member includes two cap portions that individually cover a third nozzle group of the plurality of nozzle groups and a fourth nozzle group adjacent to the third nozzle group, and a partition wall that separates the two cap portions. Part
When the cap member is attached to the inkjet head, the partition wall abuts on a region between the third nozzle group and the fourth nozzle group on the ink ejection surface where the nozzle is not formed. ,
The constant potential wiring connecting the two driver ICs of the wiring member includes an arrangement region of the driving contact portion corresponding to the third nozzle group and an arrangement region of the driving contact portion corresponding to the fourth nozzle group. The inkjet printer according to claim 4, wherein the inkjet printer passes between the two.

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