JP2006297952A - Manufacturing method for ink-jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for an ink-jet head by which machining for a piezoelectric actuator is not required and a head can be miniaturized. <P>SOLUTION: The manufacturing method includes: a process, in which a laminated body is manufactured by alternately superposing a plurality of first unpolarized piezoelectric layers respectively provided with a plurality of individual electrodes corresponding to a plurality of ink chambers for storing ink and a plurality of unpolarized piezoelectric layers respectively provided with a common electrode almost all over the entire face; a process for forming a first external electrode conductive to a plurality of the individual electrodes on a plurality of the first piezoelectric layers; a process for forming a second external electrode conductive to a plurality of the common electrodes on a plurality of second piezoelectric layers; a process for manufacturing one piezoelectric flat plate by calcinating the laminated body; and a process for making a piezoelectric layer region, where the individual electrodes and the common electrode are overlapped, as an actuator part by polarizing it with application of a high voltage to the piezoelectric flat plate via the first/second external electrodes under high temperatures. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an ink jet head that records an image by attaching ink droplets that have been ejected according to image information to a recording sheet.

  2. Description of the Related Art Conventionally, in an ink jet recording apparatus, an ink jet head of a type in which ink droplets are ejected from nozzles by pressurizing ink in an ink chamber by deformation of a piezoelectric member when voltage is applied is known. In this type of inkjet head, there is a type in which a large-diameter nozzle row and a small-diameter nozzle row are formed in parallel on a nozzle plate. In this case, normally, a plurality of independent ink chambers corresponding to the nozzles of each nozzle row are formed in communication with each other, and a plurality of piezoelectric members are provided on the substrate corresponding to each ink chamber. ing. Each piezoelectric member is provided with an individual electrode and a common electrode for applying a voltage according to image information, and the piezoelectric member is deformed when a driving voltage is applied between the electrodes.

  However, in the above inkjet head, when the piezoelectric member corresponding to the ink chamber of each nozzle array is formed, two piezoelectric plates for the large diameter nozzle array and the small diameter nozzle array having different sizes are bonded and fixed on the substrate. Thereafter, separate grooves were formed by dicer processing to form each piezoelectric member in a divided manner, so that it was necessary to prepare two types of piezoelectric plates, and it took time and labor for processing, resulting in poor productivity.

  In addition, it is necessary to separately draw out the common electrode of each piezoelectric member corresponding to the large diameter nozzle row and the common electrode of each piezoelectric member corresponding to the small diameter nozzle row on the substrate, which causes the head size to increase. It was. Furthermore, when the piezoelectric member is a laminated piezoelectric member formed by laminating a plurality of piezoelectric layers, an inactive region that does not deform even when a voltage is applied in order to prevent self-destruction (delamination) during driving. Must be provided at both ends in the longitudinal direction of each piezoelectric member, and the head size is increased due to the presence of the inactive region.

Therefore, in order to solve the above problem, the present invention is provided with a plurality of ink chambers each containing ink, and corresponding to each ink chamber, and pressurizing the ink in the ink chamber by deformation during voltage application. A method for producing an ink jet head comprising a plurality of actuator units for causing ink droplets to fly from nozzles,
An unpolarized first piezoelectric layer in which a plurality of individual electrodes are formed corresponding to the plurality of ink chambers containing ink, and an unpolarized piezoelectric layer in which a common electrode is formed on almost the entire surface are alternately arranged. A step of producing a laminate by stacking a plurality of sheets,
Forming a first external electrode connected to the plurality of individual electrodes on the plurality of first piezoelectric layers;
Forming a second external electrode connected to the plurality of common electrodes on the plurality of second piezoelectric layers;
Firing the laminate to produce one piezoelectric flat plate;
A high voltage is applied to the piezoelectric plate through the first external electrode and the second external electrode at a high temperature to polarize the piezoelectric layer region where the individual electrode and the common electrode overlap. A step of making the actuator part;
It is characterized by including.

  According to the method for manufacturing an ink jet head according to the present invention, since a plurality of active portions formed by partially polarizing one piezoelectric flat plate are actuator portions that pressurize each ink chamber. It is not necessary to divide and form a plurality of piezoelectric members by dicer processing or the like so as to individually correspond to the ink chambers, so that the manufacturing process can be simplified and the productivity is improved.

  In the laminated piezoelectric flat plate formed by laminating a plurality of piezoelectric layers, only the actuator portion corresponding to each ink chamber is an active portion that is polarized, and the other regions are all inactive regions that are not polarized. Therefore, self-destruction during driving can be prevented without taking a large inactive region. Thereby, a head can be reduced in size compared with the case where the piezoelectric member divided | segmented for every ink chamber is used.

  Furthermore, since the second external electrode can be electrically connected to the common electrode of all the actuator parts, each common electrode of the plurality of piezoelectric flat plates can be provided even when a plurality of the piezoelectric flat plates are arranged on the substrate. The space for occupying the lead-out wiring formed on the substrate for connecting to the ground can be saved, and this also makes it possible to reduce the size of the head.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows four inkjet heads corresponding respectively to yellow (Y), magenta (M), cyan (C), and black (K) inks along the paper passing direction (arrow a direction). The state which has arrange | positioned 10, 12, 14, 16 is shown. These inkjet heads 10, 12, 14, and 16 are line-type heads that extend in a direction orthogonal to the paper passing direction and are formed to have a length that covers the entire width of the recording paper P. Since the configuration of each head is the same, the yellow inkjet head 10 will be described below.

  A nozzle plate 18 as shown in FIG. 2 is fixed to the recording paper facing portion of the inkjet head 10. In the nozzle plate 18, large-diameter nozzle rows 22 formed by arranging several large-diameter nozzles 20 (for example, an inner diameter of 32 μm) in a straight line are formed in a staggered pattern along the longitudinal direction of the nozzle plate 18. In addition, the nozzle plate 18 includes a small diameter nozzle row 26 in which several small diameter nozzles 24 (for example, an inner diameter of 23 μm) are arranged in a straight line, and each large diameter nozzle row in the vicinity of both side edges along the longitudinal direction of the nozzle plate 18. 22 are formed in a zigzag pattern corresponding to each.

  As shown in FIG. 3, an ink flow path plate 28 is bonded and fixed to the nozzle plate 18. The ink flow path plate 28 is formed with a plurality of groove-shaped recesses covered with the nozzle plate 18. Of these recesses, a groove-like recess extending in two directions starting from an ink supply port 30 into which ink flows from an ink cartridge (not shown) is an ink supply chamber 32. In addition, a plurality of narrow groove-shaped recesses formed inside the ink supply chamber 32 corresponding to the large-diameter nozzles 20 are large-diameter ink chambers 34. Several large-diameter ink chambers 34 corresponding to the large-diameter nozzle row 22 are arranged in parallel to each other to form a large-diameter ink chamber row (first ink chamber row) 36. Each large-diameter ink chamber 34 communicates with the ink supply chamber 32 via a corresponding inlet groove 38, and is connected to the large-diameter nozzle 20 near the end of the large-diameter ink chamber 34 on the side opposite to the inlet groove 38. Each communicates.

  In addition, a plurality of narrow groove-shaped recesses formed on the outside of the ink supply chamber 32 corresponding to the small diameter nozzles 24 are the small diameter ink chambers 40. Several small-diameter ink chambers 40 corresponding to the small-diameter nozzle row 26 are arranged in parallel with the arrangement direction of the large-diameter ink chamber row 36 to form a small-diameter ink chamber row (second ink chamber row) 42. is doing. The small-diameter ink chamber row 42 is provided adjacent to the large-diameter ink chamber row 36 with the ink supply chamber 32 interposed therebetween. The length of the small-diameter ink chamber 40 is shorter than that of the large-diameter ink chamber 34. Each small-diameter ink chamber 40 communicates with the ink supply chamber 32 via a corresponding inlet groove 38, and is connected to the small-diameter nozzle 24 near the end of the small-diameter ink chamber 40 on the side opposite to the inlet groove 38. Each communicates.

  A plurality of single piezoelectric flat plates 50 are bonded to the back surface of the ink flow path plate 28 so as to correspond to a pair of opposing large-diameter and small-diameter ink chamber rows 36 and 42, respectively. Each piezoelectric flat plate 50 is bonded and fixed on a ceramic substrate 54 held by a holder 52. FIG. 4 shows a state where the piezoelectric flat plate 50 is arranged on the substrate 54. Grooves 56 extending in the longitudinal direction of the substrate 54 are formed at the center of the substrate 54, and the piezoelectric flat plates 50 are arranged in a staggered manner on both sides of the groove 56.

  The piezoelectric flat plate 50 is a laminated piezoelectric flat plate formed by laminating a plurality of piezoelectric layers, and is manufactured as shown in FIG. First, individual electrodes 58a and 58b are formed in advance on the surface of a green sheet 60 of a piezoelectric material (for example, PZT) as a first layer, corresponding to the ink chambers 34 and 40, by sputtering or plating. . The individual electrodes 58 a corresponding to the large-diameter ink chamber 34 are respectively formed in strips extending from one edge of the green sheet 60, and the individual electrode 58 b corresponding to the small-diameter ink chamber 40 is the other edge of the green sheet 60. It is formed in a strip shape extending from each. Corresponding to the difference in length between the ink chambers 34 and 40, the individual electrode 58a is formed longer than the individual electrode 58b. A region 62 where no electrode is formed is left at the substantially central portion of the green sheet 60.

  Next, a second green sheet 64 made of the same piezoelectric material is laminated on the first green sheet 60. On the upper surface of the green sheet 64, a common electrode 66 is formed in advance by sputtering, plating, or the like on almost the entire surface, leaving the band-like portion 65 near both ends. After that, the same green sheet as the first layer is laminated on the second green sheet 64 as the third layer, and the same green sheet as the second layer is laminated thereon as the fourth layer. After repeating a process and laminating | stacking a predetermined number (for example, 20 layers) of green sheets, the green sheet 68 in which the electrode is not formed is laminated | stacked finally, and the green sheet of each layer is closely_contact | adhered by pressing from the upper part.

  After that, as shown in FIG. 6, external electrodes 70 for conducting the individual electrodes 58b of the respective layers are formed by, for example, gold plating. Similarly, an external electrode (not shown) is formed for the other individual electrode 58a. In addition, external electrodes 72 (only one shown) are formed on both side surfaces by conducting gold plating or the like, for example, for conducting the common electrode 66 of each layer provided so as to be exposed on both side surfaces orthogonal to the side surface on which the external electrode 70 is formed. To do. And the piezoelectric flat plate 50 is completed by baking this laminated body.

  Subsequently, a high voltage is applied between the individual electrodes 58 a and 58 b and the common electrode 66 at a high temperature to partially polarize the piezoelectric plate 50. As a result, as shown in FIG. 7, regions where the individual electrodes 58 a and 58 b and the common electrode 66 overlap each other in the piezoelectric flat plate 50 become active portions, and the individual electrodes 58 a and 58 b are connected via the external electrodes 70 and 72. Actuator portions 74 and 76 that are deformed when a drive voltage is applied between the common electrodes 66 are formed. On the other hand, between the actuator parts 74 and 76, it becomes the inactive part 78 of the unpolarized state in which only the common electrode 66 exists.

  In this way, between each piezoelectric layer formed by firing a plurality of laminated green sheets, a plurality of individual electrodes 58a and 58b patterned corresponding to each actuator portion 74 and 76, and all actuator portions A plurality of common electrodes 66 that are formed so as to extend to 74 and 76 and are exposed on the side surfaces of the piezoelectric flat plate 50 are alternately arranged. In the piezoelectric flat plate 50, each actuator section 74 is provided corresponding to each ink chamber 34 of the large-diameter ink chamber row 36, and each actuator section 76 is provided in each ink chamber 40 of the small-diameter ink chamber row 42. Each is provided correspondingly. Note that the length of the actuator portion 74 is longer than that of the actuator portion 76 in accordance with the difference in length between the individual electrodes 58a and 58b.

  As shown in FIG. 4, lead wires 73 are formed on the substrate 54 so as to be electrically connected to the external electrodes 72 of the respective piezoelectric flat plates 50, and the common electrodes 66 of the respective piezoelectric flat plates 50 are connected via the lead wires 73. Connected to ground. On the other hand, on the side surface of the substrate 54, lead wires 71 are formed which are respectively connected to the external electrodes 70 formed on the side surfaces of the respective piezoelectric flat plates 50, and each piezoelectric flat plate is connected via a flexible wire connected to the lead wires 71. 50 individual electrodes 58a and 58b are connected to a drive voltage application driver (not shown).

  In the inkjet head 10 configured as described above, ink supplied from an ink cartridge (not shown) to the ink supply chamber 32 is accommodated in each of the large-diameter and small-diameter ink chambers 34 and 40 via the corresponding inlet grooves 38. . In this state, when a driving voltage is applied between the individual electrodes 58a and 58b and the common electrode 66 of the piezoelectric flat plate 50 from the driver according to the image information, the actuator portions 74 and 76 are instantly deformed in the thickness direction. The ink in each of the ink chambers 34 and 40 is pressurized, whereby ink droplets having different sizes fly from the large diameter nozzle 20 and the small diameter nozzle 24. These ink droplets adhere to the recording paper to form dots of different sizes, and an image is recorded by a set of these dots.

As described above, in the ink jet head 10 manufactured in the present embodiment, an actuator unit in which a plurality of active units formed by partially polarizing one piezoelectric flat plate 50 pressurizes the ink chambers 34 and 40, respectively. 74 and 76, it is not necessary to divide and form the piezoelectric member by dicer processing or the like so as to correspond to the ink chambers 34 and 40, respectively, and the manufacturing process can be simplified and the productivity is improved. In addition, since one piezoelectric flat plate 50 can cover the actuator portions 74 and 76 corresponding to the ink chambers 34 and 40 of the large-diameter and small-diameter ink chamber rows 36 and 42, respectively, it can be used for a large diameter as in the past. In addition, there is no need to prepare two types of piezoelectric plates of different sizes for the small-diameter ink chamber row, so that the type and cost of parts can be reduced, and the positioning of the two piezoelectric plates is not required during assembly. Becomes easier.
These effects can be obtained even if the piezoelectric flat plate 50 is not a laminated type but a single layer.

  Further, in the laminated piezoelectric flat plate 50 formed by laminating a plurality of piezoelectric layers, only the actuator portions 74 and 76 corresponding to the ink chambers 34 and 40 are the active portions that are polarized, and all other regions are the same. Since it is a non-polarized inactive region, the inactive portion 78 between the actuator portion 74 corresponding to the large diameter ink chamber row 36 and the actuator portion 76 corresponding to the small diameter ink chamber row 42 is not so large. However, self-destruction (delamination) during driving can be prevented. Thereby, the head can be reduced in size as compared with the case where the piezoelectric member divided for each ink chamber 34, 40 of each ink chamber row 36, 42 is provided.

  Furthermore, it is formed between each piezoelectric layer of the laminated piezoelectric flat plate 50 so as to extend to each of the plurality of individual electrodes 58a, 58b and all the actuator portions 74, 76 corresponding to the actuator portions 74, 76, respectively. In addition, since the plurality of common electrodes 66 provided so as to be exposed on the side surface of the piezoelectric flat plate 50 are alternately arranged, by providing an external electrode 72 such as gold plating on the side surface where the common electrode 66 is exposed. The electrical connection of the common electrode 66 of all the actuator portions 74 and 76 can be established from the external electrode 72. This is necessary when the common electrode wiring is separately drawn on the substrate from each piezoelectric member corresponding to the large-diameter ink chamber row 36 and each piezoelectric member corresponding to the small-diameter ink chamber row 42. Space can be saved, and this also reduces the size of the head.

  Incidentally, in the ink jet head 10, a piezoelectric flat plate 80 shown in FIG. 8 may be used instead of the piezoelectric flat plate 50. In the piezoelectric flat plate 80, grooves 82 for dividing each common electrode 66 are formed in a non-active portion where only the common electrode 66 exists in the piezoelectric flat plate 50 by dicer processing or the like, and a conductive adhesive is formed in the groove 82. 84. When this piezoelectric flat plate 80 is used, the presence of the groove 82 causes mutual vibration between the actuator portion 74 on the large diameter ink chamber row 36 side and the actuator portion 76 on the small diameter ink chamber row 42 side. In combination, it is possible to suppress the interlocking displacement. In addition, the common electrode 66 extending from the conductive adhesive 84 filled in the groove 82 to all the actuator portions 74 and 76 can be electrically connected, and space saving is achieved as in the case of the piezoelectric flat plate 50. The size of the head can be reduced, and self-destruction (delamination) of the piezoelectric flat plate 80 in the groove 82 can be prevented by the adhesive force of the adhesive 84. In the piezoelectric flat plate 80, since the common electrode 66 can be electrically connected from the conductive adhesive 84, it is not necessary to provide the external electrode 72 by gold plating or the like on the side surface unlike the piezoelectric flat plate 50.

  In the inkjet head 10 described above, the diameters of the nozzles 20 and 24, the lengths of the ink chambers 34 and 40, and the lengths of the actuator portions 74 and 76 are made different to discharge large and small ink droplets. The present invention can also be applied to the case where the nozzle diameter, the ink chamber length, and the actuator portion length are formed to be the same.

  The ink jet head 10 has been described as a line type head, but the present invention can also be applied to the production of an ink jet head that is attached to a carriage and scans a recording sheet.

FIG. 3 is a perspective view showing a state in which four line-type ink jet heads are arranged along the sheet passing direction of recording paper. The top view which shows the nozzle surface of a line type inkjet head. FIG. 2 is a partially cutaway perspective view showing the internal configuration of the inkjet head. The partial perspective view which shows the state which has arrange | positioned the several piezoelectric flat plate on a board | substrate. The perspective view for demonstrating the lamination | stacking state of a piezoelectric flat plate. The perspective view of a piezoelectric flat plate. FIG. 7 is a sectional view taken along line VII-VII of the piezoelectric flat plate of FIG. 6. The perspective view which shows the piezoelectric flat plate of another form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inkjet head 34 ... Large diameter ink chamber 36 ... Large diameter ink chamber row 40 ... Small diameter ink chamber 42 ... Small diameter ink chamber row 50 ... Piezoelectric flat plates 74, 76 ... Actuator section.

Claims (1)

A plurality of ink chambers that respectively store ink, and a plurality of actuator units that are provided corresponding to the respective ink chambers and pressurize the ink in the ink chamber by deformation when a voltage is applied to eject ink droplets from the nozzles. A method for producing an inkjet head comprising:
An unpolarized first piezoelectric layer in which a plurality of individual electrodes are formed corresponding to the plurality of ink chambers containing ink, and an unpolarized piezoelectric layer in which a common electrode is formed on almost the entire surface are alternately arranged. A step of producing a laminate by stacking a plurality of sheets,
Forming a first external electrode connected to the plurality of individual electrodes on the plurality of first piezoelectric layers;
Forming a second external electrode connected to the plurality of common electrodes on the plurality of second piezoelectric layers;
Firing the laminate to produce one piezoelectric flat plate;
A high voltage is applied to the piezoelectric plate through the first external electrode and the second external electrode at a high temperature to polarize the piezoelectric layer region where the individual electrode and the common electrode overlap. A step of making the actuator part;
A method for manufacturing an ink-jet head, comprising:

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