JP4333275B2 - Inkjet head - Google Patents

Description

  The present invention relates to a so-called chopper traverse type inkjet head having an actuator substrate in which a large number of parallel ink channels separated by a partition wall are recessed from a front end to a midway portion on the rear end side.

  Conventionally, the ink jet head described in Patent Document 1 is known. This is shown in FIG.

  In the figure, 100A and 100B are actuator substrates, 101 is a cover substrate, 102 is a connection substrate, 103 is a nozzle plate, and 104A and 104B are LSI chip terminals.

  In each actuator substrate 100A, 100B, the ink channels 105A, 105B are recessed on the opposite surfaces with a length extending from the front end (right end in the drawing) to the middle portion of the rear end side (left end in the drawing) of the actuator substrate 100A, 100B. The cover substrate 101 is bonded to the front end side between the ink channels 105A and 105B so as to leave a part of the rear end side of the ink channels 105A and 105B.

  The connection substrate 102 is bonded to the rear end side between the actuator substrates 100A and 100B. Depending on the space formed by the connection substrate 102, the cover substrate 101 and the actuator substrates 100A and 100B, each ink channel 105A, An ink flow path 106 for distributing ink to 105B is formed.

  Each actuator substrate 100A, 100B is provided with connecting recesses 107A, 107B on the rear end side of the same surface as the ink channels 105A, 105B. The electrodes in the ink channels 105A, 105B Extending from the opposing surfaces of the actuator substrates 100A, 100B to the coupling recesses 107A, 107B, and inserting the chip terminals 104A, 104B into the coupling recesses 107A, 107B, the ink channels 105A, The electrodes in 105B are electrically connected to the drive circuit.

According to the ink jet head described in Patent Document 1, since each ink channel 105A, 105B can be covered with a single cover substrate 101, it is expensive even when a high density is achieved with a multi-row nozzle array. The use amount of the cover substrate 101 can be reduced, and the ink channel 106 can be easily formed by simply sealing the rear end side between the actuator substrates 100A and 100B with the connection substrate 102. is there.
Japanese Patent No. 2961624

  In general, an actuator substrate is deformed by a voltage applied to an electrode, and a piezoelectric material is used to change the pressure of ink in each ink channel and eject the ink from a nozzle. Then, since the entire area from the front end where the nozzle is arranged to the connecting recesses 107A and 107B for electrical connection with the chip terminals 104A and 104B must be formed by the actuator substrates 100A and 100B, the actuator substrate 100A , The length of 100B is increased, and as a result, the amount of piezoelectric material used is increased, resulting in an increase in cost, and an increase in electric capacity leads to an increase in heat generation and an increase in drive power supply. There's a problem.

  Further, in the inkjet head described in Patent Document 1, when the actuator substrates 100A and 100B and the connection substrate 102 are bonded, the adhesive applied to the bonding surface flows into the coupling recesses 107A and 107B. Therefore, the connection with the chip terminals 104A and 104B must be made before the connection substrate 102 is bonded. However, in this case, after connecting the chip terminals 104A and 104B electrically connected to the drive circuit for each actuator substrate 100A and 100B, the actuator substrates 100A and 100B with the chip terminals 104A and 104B are connected to the cover substrate 101. In addition, since both sides of the connection substrate 102 have to be adhered, there is a problem that workability is extremely poor and it is difficult to prepare.

  Accordingly, an object of the present invention is an inkjet head that is densified by providing an actuator substrate with recessed ink channels on both sides of a cover substrate, and can reduce the amount of piezoelectric material used and drive It is an object of the present invention to provide an ink jet head that can be easily electrically connected to a circuit and can be easily formed.

  Other problems of the present invention will become apparent from the following description.

  According to the first aspect of the present invention, the ink channel forming surfaces of the actuator substrate in which a large number of parallel ink channels separated by a partition wall are provided on both surfaces of the cover substrate from the front end to the midway portion on the rear end side. In addition to bonding, a connection substrate is provided on the opposing surface on the rear end side of each actuator substrate and sealed, and ink is applied to each ink channel by a space between the cover substrate, the connection substrate, and each actuator substrate. An ink jet head having an ink flow path to be distributed, wherein the connection substrate protrudes rearward from a rear end of each actuator substrate, and an electrode for applying a voltage to each partition wall From the partition wall in the ink channel through the opposing surface on the rear end side of each actuator substrate and the surface of the connection substrate opposing the surface It has been drawn out to the outside Te is an inkjet head according to claim.

  According to a second aspect of the present invention, the ink channel forming surfaces of the actuator substrate in which a large number of parallel ink channels separated by a partition wall are provided on both surfaces of the cover substrate from the front end to the midway portion on the rear end side. In addition to bonding, a connection substrate is provided on the opposing surface on the rear end side of each actuator substrate and sealed, and ink is applied to each ink channel by a space between the cover substrate, the connection substrate, and each actuator substrate. An ink jet head formed with an ink flow path to be distributed, wherein the connection substrate protrudes rearward from one rear end of the actuator substrate, and the other of the actuator substrates Projecting rearward from the rear end of the connection board, voltage is applied to each partition wall of the one actuator board. The electrodes to be pulled out from the partition in each ink channel to the outside through the opposing surface on the rear end side and the surface of the connection substrate facing the surface, and voltage is applied to each partition in the other actuator substrate. The electrode to be applied is an ink jet head characterized in that the electrode is pulled out from the partition wall in each ink channel to the outside on the rear side of the connection substrate through the opposing surface on the rear end side.

  According to a third aspect of the present invention, in the other actuator substrate, ink channels are recessed on both surfaces, and the one actuator substrate is provided on each surface with the cover substrate and the connection substrate interposed therebetween. The inkjet head according to claim 2.

  The invention described in claim 4 is characterized in that each of the electrodes drawn out to the outside is electrically connected to a drive circuit via an FPC (flexible printed circuit board) outside the outside. Or it is an inkjet head of 3 description.

  According to the present invention, it is possible to reduce the amount of piezoelectric material used in a high-density ink-jet head by providing actuator substrates with recessed ink channels on both sides of the cover substrate, and the electrical connection with the drive circuit. It is possible to provide an ink jet head that can be easily connected and can be easily produced.

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

  FIG. 1 is a sectional view showing a first embodiment of an ink jet head according to the present invention, and FIG. 2 is a partial perspective view showing the structure of an actuator.

  The actuator substrate 1 (1A, 1B) is mainly composed of a piezoelectric material in which a large number of ink channels 11 (11A, 11B) are arranged in parallel.

  As the piezoelectric material, a known piezoelectric material that is deformed by applying a voltage can be used, and examples thereof include a substrate made of an organic material and a non-metallic substrate. In particular, a non-metallic piezoelectric material substrate is preferable, and includes a piezoelectric ceramic substrate formed through processes such as molding and firing, or a substrate formed without requiring molding and firing.

In a non-metallic piezoelectric material substrate, lead zirconate titanate (PZT) is preferable as the piezoelectric ceramic substrate formed through processes such as molding and firing. Furthermore, BaTiO ₃ , ZnO, LiNbO ₃ , LiTaO ₃ or the like may be used.

PZT includes PZT (PbZrO ₃ —PbTiO ₃ ) and third component added PZT. As the third component to be added, Pb (Mg _1/2 Nb _2/3 ) O ₃ , Pb (Mn _1/3 Sb _2/3 ) O ₃ , Pb (Co _1/3 Nb _2/3 ) O _3, etc. is there.

  Moreover, as a board | substrate formed without requiring shaping | molding and baking in a nonmetallic piezoelectric material board | substrate, it can form by the sol-gel method, the laminated substrate coating method, etc., for example.

  The plurality of ink channels 11 are formed by cutting grooves in parallel from the upper surface of the actuator substrate 1 with a diamond blade or the like. The individual ink channels 11 are cut into a linear, elongated groove shape extending from the front end (left end in FIG. 1) to the rear end (right end in FIG. 1) of the actuator substrate 1, and the uncut piezoelectric material is left for each ink. A partition wall 12 is formed between the channels 11. Accordingly, the ink channels 11 and the partition walls 12 are alternately arranged in parallel. Each ink channel 11 is recessed from the front end of the actuator substrate 1 to a midway portion on the rear end side, gradually becoming shallower toward the rear end side, and finally disappears.

  Electrodes 13 (13A, 13B) are formed on a part of the inner surface of each ink channel 11 (the surface of the partition wall 12). The metal forming the electrode 13 includes Ni (nickel), Co (cobalt), Cu (copper), Al (aluminum), etc., and Ni and Cu are preferable, and Ni is particularly preferable, and plating, vapor deposition, and the like are preferable. It can be formed by sputtering.

  The electrode 13 in each ink channel 11 is led out to the upper surface 1a on the rear end side of the actuator substrate 1 through the shallow groove portion 11 '(11A', 11B ') on the rear end side of the ink channel 11. Accordingly, the electrodes 13 are arranged in parallel at the same pitch as the ink channels 11 on the upper surface 1 a on the rear end side of the actuator substrate 1.

  The actuator substrate 1 made of a piezoelectric material is polarized, and when a voltage is applied from the direction perpendicular to the polarization direction by applying a voltage to the electrode 13 formed on the surface of the partition wall 12, the partition wall 12 is caused by the piezoelectric sliding effect. The ink channel 11 is deformed by shearing into a square shape, and the volume of the ink channel 11 is changed, and a pressure change is applied to the ink in the ink channel 11.

  The actuator substrates 1A and 1B having such a structure are formed so that the surfaces on which the ink channels 11A and 11B of the actuator substrates 1A and 1B are formed are opposed to both surfaces of the cover substrate 2 and the front ends of the actuator substrates 11A and 11B. And the actuator substrate 11A, 11B and the cover substrate 2 are bonded together, and the nozzles 3A, 3B corresponding to the ink channels 11A, 11B are provided at the front ends thereof. The one nozzle plate 3 with the opening is bonded. The ink to which the pressure change is applied in the ink channel 11 is ejected to the outside as ink droplets from the nozzles 3A and 3B, and is landed on the recording medium to record an image.

  The cover substrate 2 can be made of, for example, a material containing aluminum nitride as a component, a non-polarized piezoelectric material, a liquid crystal polymer, or the like. Further, the thermal expansion coefficient is equal to the thermal expansion coefficient of the actuator substrate 1. What is +/- 2 ppm / degreeC is preferable. By setting the thermal expansion coefficient within this range, separation or the like due to the difference in thermal expansion coefficient does not occur between the substrates.

  The length of the cover substrate 2 (the length in the left-right direction in FIG. 1) is longer than the length in the extending direction of the ink channels 11A, 11B of each actuator substrate 1A, 1B (the length in the left-right direction in FIG. 1). Accordingly, the cover substrate 2 does not exist in the vicinity of the shallow groove portions 11A ′ and 11B ′ on the rear end side of the ink channels 11A and 11B, and the actuator substrates 1A and 1B face each other directly.

  A single connection substrate 4 is bonded between the rear end sides of the actuator substrates 1A and 1B, and the space on the rear end side of the actuator substrates 1A and 1B is sealed. The connection substrate 4 can be made of the same material as that of the cover substrate 1 and is bonded to the surfaces of the actuator substrates 1A and 1B where the ink channels 11A and 11B are not formed. As a result, spaces surrounded by the actuator substrates 1A and 1B, the cover substrate 2 and the connection substrate 4 are formed, and the ink flow paths 5 for distributing ink to the ink channels 11A and 11B are formed by the spaces. Yes. Note that the cover substrate 2 and the connection substrate 4 may be separate, but may be a single body formed by a single substrate having an opening for the ink flow path 5.

  The rear end of the connection substrate 4 protrudes rearward from the rear ends of the actuator substrates 1A and 1B, and the protruding surface is exposed to the outside. The connection surfaces of the connection substrate 4 to the actuator substrates 1A and 1B are electrically connected to the electrodes 13A and 13B drawn to the upper surface 1a (see FIG. 2) on the rear end side of the actuator substrates 1A and 1B, respectively. The extraction electrodes 4A and 4B are provided in parallel at the same pitch so as to correspond to the electrodes 13A and 13B. Accordingly, the electrodes 13A and 13B in the ink channels 11A and 11B are inverted from the rear ends of the opposing actuator substrates 1A and 1B so as to face opposite directions on the surface of the connection substrate 4 by the extraction electrodes 4A and 4B. The electrodes 13A and 13B in the ink channels 11A and 11B are respectively drawn from the rear end side of the actuator substrates 1A and 1B by using the lead electrodes 4A and 4B drawn to the outside. A voltage can be applied.

  Wiring for electrically connecting to the drive circuit is connected to the extraction electrodes 4A and 4B exposed to the outside of the connection substrate 4. In the present embodiment, FPCs (flexible printed circuit boards) 6A and 6B are joined using anisotropic conductive films, and a drive voltage from a drive circuit (not shown) is supplied to each ink channel 11A via the FPCs 6A and 6B. , 11B are applied to the electrodes 13A, 13B.

  In the present invention, since both sides exposed to the outside of the connection substrate 4 can be electrically connected to the drive circuit in this way, terminals are inserted into the connection recesses as in the prior art. Unlike the connection method, after the inkjet head is manufactured, surface bonding using FPC 6A, 6B, or the like can be performed. In particular, by using the FPCs 6A and 6B, there is an advantage that the wiring drawing direction can be freely taken using the flexibility of the FPC.

  Moreover, since the surface exposed to the outside of the connection substrate 4 can be easily protected with the tape or strippable resist or the like on the surface when the actuator substrates 1A and 1B are bonded, the surface extraction electrodes 4A and 4B can be easily protected. Even if the adhesive flows out, the problem of poor conduction with the FPCs 6A and 6B can be easily solved.

  In the present invention, the actuator substrates 1A and 1B made of a piezoelectric material need only have a space for bonding the connection substrate 4 while leaving a space for the ink flow path 5 on the rear end side. The actuator substrates 1A and 1B can be shortened compared to the conventional one, and the amount of expensive piezoelectric material used can be reduced, the electric capacity can be reduced, the heat generated during driving and the drive power source can be enlarged. It is possible to suppress.

  FIG. 3 is a cross-sectional view showing a second embodiment of the inkjet head according to the present invention. The same reference numerals as those in FIG. 1 denote the same components, and a description thereof will be omitted unless there is a particular difference.

  As shown in the figure, the connection substrate 4 protrudes rearward from the rear end of one of the actuator substrates 1A and 1B (upper side in the drawing) of the actuator substrate 1A, but the other (lower side in the drawing) actuator. The rear end of the substrate 1 </ b> B protrudes rearward from the rear end of the connection substrate 4. Accordingly, the electrode 13A of one actuator substrate 1A is drawn to the outside by the lead electrode 4A formed on the surface of the connection substrate 4, and is electrically connected to the drive circuit by the FPC 6A as in the first embodiment. In the other actuator substrate 1B, each electrode 13B drawn to the upper surface 1a (see FIG. 2) on the rear end side is exposed as it is behind the connection substrate 4 and is electrically connected to the drive circuit by the FPC 6A. .

  According to the ink jet head according to the second embodiment, the joining operation with the FPCs 6A, 6B and the like can be easily performed after the head is manufactured as in the first embodiment, and the direction of the joining operation can be changed. Since both can be in the same direction (one direction from the top to the bottom in the figure), the work for joining the FPCs 6A and 6B using a jig or the like is facilitated. In this case, the joining work may be performed in the order of FPC 6B and FPC 6A.

  In this case as well, since one actuator substrate 1A can be made shorter than the conventional one, it is a matter of course that the amount of piezoelectric material used can be reduced accordingly.

  As a modification of the ink jet head shown in the second embodiment, as shown in FIG. 4, ink channels 11B are respectively provided on both surfaces of the lower actuator substrate 1B in FIG. An inkjet head in which the inkjet head shown in FIG.

  Here, four nozzles 3A, 3B, 3C, and 3D corresponding to the ink channels 11A, 11B, 11B, and 11A, respectively, are opened on one nozzle plate 3 in the drawing. According to this ink jet head, the same effect as that of the ink jet head shown in FIG. 3 can be obtained, and the density can be further increased.

Sectional drawing which shows 1st Embodiment of the inkjet head which concerns on this invention. Partial perspective view showing the structure of the actuator Sectional drawing which shows 2nd Embodiment of the inkjet head which concerns on this invention. Sectional drawing which shows the modification of 2nd Embodiment Sectional view showing a conventional inkjet head

Explanation of symbols

1, 1A, 1B: Actuator substrate 11, 11A, 11B: Ink channel 12: Partition wall 13, 13A, 13B: Electrode 2: Cover substrate 3: Nozzle plates 3A to 3D: Nozzle 4: Connection substrate 4A, 4B: Lead electrode 5 : Ink channel 6A, 6B: FPC

Claims (4)

  Adhering the ink channel forming surfaces of the actuator substrate in which a large number of parallel ink channels separated by a partition wall are recessed from the front end to the middle of the rear end on both sides of the cover substrate, and each actuator substrate A connection substrate is provided on the opposite surface on the rear end side and sealed, and an ink flow path for distributing ink to each ink channel is formed by a space between the cover substrate, the connection substrate, and each actuator substrate. The connection substrate protrudes rearward from the rear end of each actuator substrate, and an electrode for applying a voltage to each partition wall is connected to each actuator from the partition wall in each ink channel. Pulled out to the outside through the opposing surface on the rear end side of the substrate and the surface of the connection substrate opposing the surface Ink jet head, characterized in that there.   Adhering the ink channel forming surfaces of the actuator substrate in which a large number of parallel ink channels separated by a partition wall are recessed from the front end to the middle of the rear end on both sides of the cover substrate, and each actuator substrate A connection substrate is provided on the opposite surface on the rear end side and sealed, and an ink flow path for distributing ink to each ink channel is formed by a space between the cover substrate, the connection substrate, and each actuator substrate. The connection board protrudes rearward from the rear end of one of the actuator boards, and the other of the actuator boards is rearward of the rear end of the connection board. The electrodes for applying a voltage to each of the partition walls of the one actuator substrate are An electrode for applying a voltage to each partition wall in the other actuator substrate, which is drawn out from the partition wall in the channel to the outside through the opposing surface on the rear end side and the surface of the connection substrate facing the surface, An ink-jet head, wherein the ink-jet head is pulled out from the partition wall in each ink channel to the outside on the rear side of the connection substrate through a facing surface on the rear end side.   3. The other actuator substrate according to claim 2, wherein ink channels are recessed on both surfaces, and the one actuator substrate is provided on each surface with the cover substrate and the connection substrate interposed therebetween. Inkjet head.   4. The ink jet head according to claim 1, wherein each of the electrodes drawn out to the outside is electrically connected to a driving circuit through an FPC (flexible printed circuit board) outside the electrode.

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