JP2006082392A - Inkjet recording head and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head without protrusion of an adhesive and an inkjet recording device. <P>SOLUTION: Ink in a pressure chamber is jetted out from a nozzle in the form of droplets after pressurizing the ink by electrostriction action of a plate-like piezoelectric actuator in the inkjet recording head. The inkjet recording head is composed so that an adhesive relieving part for storing the adhesive is formed over the entire periphery of an adhering face on the side adhered to a vibrating plate of the piezoelectric actuator. The inkjet recording device is provided with the inkjet recording head. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inkjet recording head and an inkjet recording apparatus, and in particular, in an inkjet recording head having a plate-like piezoelectric actuator in which a piezoelectric drive unit and an electrode pad unit are formed on the same plane, the piezoelectric actuator is bonded to a diaphragm. The present invention relates to an ink jet recording head capable of suppressing the protrusion of an adhesive when the ink jet recording is performed and an ink jet recording apparatus having the ink jet recording head.

  2. Description of the Related Art As an ink jet recording apparatus, an apparatus that ejects ink by vibrating a diaphragm with a piezoelectric element such as a piezoelectric element is widely used.

  As the piezoelectric element, a columnar element has been generally used so far (Patent Documents 1 to 3).

In recent years, a plate-like ink jet recording head is obtained by bonding a plate-like piezoelectric actuator to a diaphragm provided on the opposite side of the nozzle of a flow path plate unit formed by laminating a diaphragm, a chamber plate, a nozzle plate, etc. It was proposed to form (Patent Document 4).
Japanese Patent No. 3478297 JP 2001-63039 A Japanese Patent No. 2933608 Japanese Patent Laid-Open No. 2002-248608

  However, in the plate-shaped ink jet recording head, when the adhesive protrudes around the piezoelectric actuator, the protruded adhesive adheres to the side surface of the piezoelectric actuator in a fillet shape and solidifies as shown in FIG. Therefore, the constraint condition of the piezoelectric actuator changes. Also, it is almost impossible to control the amount of adhesive protruding.

  Accordingly, when the adhesive protrudes, the vibration characteristics of the piezoelectric actuator and the vibration plate vary, and the ink discharge characteristics from the nozzles are also affected.

  If the amount of protrusion of the adhesive increases, as shown in FIG. 10B, adjacent piezoelectric actuators are connected with the adhesive solidified in a fillet shape, and crosstalk may occur during ink ejection. .

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an ink jet recording head having no protruding adhesive and an ink jet recording apparatus including the ink jet recording head.

  The invention according to claim 1 is an ink jet recording head that pressurizes ink in a pressure chamber by an electrostrictive action of a plate-shaped piezoelectric actuator and ejects the ink from a nozzle in a droplet shape, and is bonded to the diaphragm of the piezoelectric actuator. The present invention relates to an ink jet recording head characterized in that an adhesive escape portion for containing the adhesive is formed over the entire circumference of the adhesive surface on the side to be formed.

  In the ink jet recording head, even when the adhesive is excessively applied to the adhesive surface of the piezoelectric actuator, the adhesive pushed out of the piezoelectric actuator is not removed from the adhesive escape portion provided over the entire circumference of the adhesive surface. It is housed inside and does not protrude outside the piezoelectric actuator.

  Accordingly, it is possible to effectively prevent variations in ink ejection characteristics due to the protruding adhesive and occurrence of crosstalk during ink ejection.

  In the piezoelectric actuator, since the piezoelectric drive unit and the electrode pad unit are connected, it is not necessary to electrically connect the two.

  A second aspect of the present invention relates to the ink jet recording head according to the first aspect, wherein the adhesive escape portion is a step having a certain width.

  A third aspect of the present invention relates to the ink jet recording head according to the first aspect, wherein the adhesive escape portion is a chamfered portion having a constant width.

  In the ink jet recording head, since the adhesive escape portion is a step or chamfered portion having a certain width, an adhesive escape portion can also be formed when the piezoelectric actuator is formed by the sandblast method.

  According to a fourth aspect of the present invention, there is provided the inkjet recording head according to any one of the first to third aspects, wherein the gap between the piezoelectric actuators on the surface opposite to the surface on which the nozzles of the nozzle assembly are formed. The present invention relates to an ink jet recording head in which a remaining dummy plate to which no voltage is applied is bonded at a position where the voltage is filled.

  When a piezoelectric actuator is bonded to the diaphragm of the flow path forming member in a matrix, a gap is often left between two adjacent piezoelectric actuators. However, in the ink jet recording head, since the remaining dummy plate is bonded to fill the gap between the piezoelectric actuators, stress is prevented from concentrating on the portion of the vibration plate that is not driven by the piezoelectric actuator.

  The remaining dummy plate can be formed together with the piezoelectric actuator from one piezoelectric plate.

  According to a fifth aspect of the present invention, in the ink jet recording head according to any one of the first to fourth aspects, the bonding is performed over the entire circumference of the bonding surface of the remaining dummy plate that is bonded to the vibration plate. The present invention relates to an ink jet recording head in which an adhesive escape portion for containing an agent is formed.

  In the ink jet recording head, the adhesive pushed out of the piezoelectric actuator and the remaining dummy plate not only on the bonding surface of the remaining dummy plate but also on the bonding surface of the remaining dummy plate not only on the piezoelectric actuator, It is accommodated inside the adhesive escape portion that is provided across and does not protrude outside the piezoelectric actuator.

  Therefore, in the ink jet recording head having the remaining dummy plate, it is possible to effectively prevent variations in ink ejection characteristics due to the protruding adhesive and occurrence of crosstalk during ink ejection.

  A sixth aspect of the present invention relates to an ink jet recording head according to the fifth aspect, wherein the piezoelectric actuator and the remaining dummy plate are formed in the same shape.

  In the inkjet recording head, all the piezoelectric actuators are formed in the same shape, and similarly, all the remaining dummy plates are also formed in the same shape. Therefore, the piezoelectric actuators and the remaining dummy plates are alternately arranged in a matrix. In this case, the manufacturing is easy.

  A seventh aspect of the present invention relates to an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to sixth aspects.

  According to the first aspect of the present invention, in the ink jet recording head, since the adhesive is prevented from protruding around the piezoelectric actuator, the variation in the ink ejection characteristics of the nozzles caused by the protrusion of the adhesive and the crosstalk. Can be suppressed.

  As described above, according to the present invention, it is possible to effectively prevent variations in ink discharge characteristics for each nozzle due to the protrusion of the adhesive around the piezoelectric actuator and occurrence of crosstalk during ink discharge.

1. Embodiment 1
An example of the ink jet recording head and the ink jet recording apparatus according to the present invention will be described below.

  The structure of the inkjet recording head 112 of Embodiment 1 is shown in FIGS. 1, 2A, and 2B. 2A shows a configuration of the ink jet recording head 112 viewed from the piezoelectric actuator 42 side, and FIG. 2B shows a cross section cut along a plane AA shown in FIG.

  As shown in FIG. 1 and FIG. 2, the inkjet recording head 112 has nozzles 10 formed in a matrix on one surface, and ink is supplied to the pressure chambers 14 communicating with the nozzles 10 inside and the pressure chambers 14. A flow path plate unit 60 in which a common ink chamber 20 is formed is provided. The flow path plate unit 60 is an example of a flow path forming member in the present invention. The flow path plate unit 60 further includes a nozzle communication chamber 12 that communicates the pressure chamber 14 and the nozzle 10, a thickness direction communication passage 18 that communicates the pressure chamber 14 and the common ink chamber 20, and a planar communication passage 16. And are formed. The flow path plate 60 is formed by laminating the nozzle plate 21, the ink pool plate 22, the ink pool plate 23, the through plate 24, the ink supply path plate 26, and the pressure chamber plate 28 in this order.

  As shown in FIG. 1 and FIG. 2, the pressure chamber 14 has a ratio of two diagonal lengths of approximately 1, and has a substantially rhombic planar shape in which each vertex is rounded into an arc.

  The diaphragm 30 is bonded to the surface of the flow path plate unit 60 opposite to the side where the nozzles 10 are formed, and the ceiling of the pressure chamber 14 is formed by the diaphragm.

  As shown in FIGS. 3 and 4, a group of piezoelectric actuators 42 and a remaining dummy plate 44 are bonded to the outer surface of the diaphragm 30 in a matrix. The piezoelectric actuator 42 and the remaining dummy plate 44 are formed by forming separation slits 40 with a certain width in the piezoelectric plate 72 as shown in FIG.

  The piezoelectric actuator 42 is divided into a piezoelectric drive part 42A and an electrode pad part 42B as shown in FIGS. The piezoelectric drive unit 42A is a drive unit that is deformed by electrostriction and pressurizes the ink in the pressure chamber 14, and the electrode pad unit 42B is a portion to which an electrode for applying a voltage to the piezoelectric drive unit 42A is connected. It is.

  The piezoelectric drive unit 42A has a substantially rhombic planar shape in which the ratio of the lengths of two diagonal lines that are substantially similar to the planar shape of the pressure chamber 14 is approximately 1, and each vertex is rounded into an arc. Yes.

  The electrode pad portion 42B has a ¼ circular fan shape along the outer periphery of the piezoelectric drive portion 42A, and the apex of the fan shape coincides with the center point of the substantially diamond-shaped piezoelectric drive portion 42A. It is formed so as to be divided into two by the longer diagonal line of the two diagonal lines of the piezoelectric drive unit 42A.

  At both end portions of the electrode pad portion 42B, recessed portions 42C that are recessed inward are formed.

  At the same time, a bent portion 42D that is recessed inward is formed at the connection portion between the piezoelectric drive portion 42A and the electrode pad portion 42B so that the bending deformation due to the electrostrictive action of the piezoelectric drive portion 42A is not hindered. .

  A circuit board 36 is connected to the electrode pad portion 42 </ b> B via a solder ball 34. Therefore, a predetermined voltage is applied from the circuit board 36 to the electrode pad portion 42B via the solder ball 34, and thereby the piezoelectric driving portion 42A is driven to pressurize and depressurize the inside of the pressure chamber 14.

  On the other hand, the remaining dummy plate 44 is formed in a substantially parallelogram shape, and the apex on the side facing the electrode pad portion 42B of the piezoelectric actuator and its vicinity are formed in a concave curve shape corresponding to the shape of the electrode pad portion 42B. In other words, it is formed in a concave curve shape corresponding to the shape of the piezoelectric drive part 42A of the piezoelectric actuator on the side opposite to the apex.

  As shown in FIGS. 2 and 4, an adhesive escape portion 41 is formed on the entire circumference of the peripheral portion of the piezoelectric actuator 42. 5 and 6 show cross sections obtained by cutting the ink jet recording head 112 along the plane BB shown in FIG. The adhesive escape portion 41 may be a recessed portion provided in the peripheral portion of the piezoelectric actuator 42 as shown in FIG. 5, and is a chamfered portion chamfered in a curved shape as shown in FIG. There may be. Further, it may be a chamfered surface that is obliquely chamfered as shown in FIG.

  When an excessive amount of adhesive is applied to the piezoelectric actuator 42, the adhesive is pushed toward the peripheral edge of the piezoelectric actuator 42 by the piezoelectric actuator 42 and the vibration plate 30. As shown in FIGS. 5 and 6, the adhesive pushed out toward the peripheral portion is accommodated in the adhesive escape portion 41, and is not pushed outward further.

  Hereinafter, the manufacturing procedure of the inkjet recording head 112 will be described with reference to FIGS.

  First, as shown in FIG. 7A, the thickness of the nozzle plate 21, the ink pool plate 22 and the ink pool plate 23 in which the nozzle communication chamber 12 and the common ink chamber 20 are formed, and the thickness of the common ink chamber 20. A through plate 24 in which the directional communication path 18 and the nozzle communication chamber 12 are formed, an ink supply path plate 26 in which the planar communication path 16 is formed, and a pressure chamber plate 28 in which the pressure chamber 14 is formed. Laminate and join in order.

  Next, as shown in FIG. 7B, the surface of the nozzle plate 21 is covered with a water repellent coating film, and the nozzle 10 is opened on the nozzle plate 21 with the excimer laser 50.

  Then, as shown in FIG. 3C, the diaphragm 30 is bonded to the pressure chamber plate 28.

  The material of the nozzle plate 21 is polyimide, and the material of the ink pool plate 22, the ink pool plate 23, the through plate 24, the ink supply path plate 26, the pressure chamber plate 28, and the vibration plate 30 is SUS.

  Next, separately, a piezoelectric unit 62 including a piezoelectric actuator 42, a remaining dummy plate 44, and a fixed substrate 70 described later is formed.

  As shown in FIG. 8A, lapping is performed on a piezoelectric material block (not shown) to create a piezoelectric plate 72. The thickness of the piezoelectric plate 72 is determined based on the amount of deflection deformation and the driving voltage required for the piezoelectric actuator 42. In this embodiment, it is 35 μm.

  Electrode films are formed on both surfaces of the piezoelectric plate 72 by sputtering or the like. As the electrode film material, chromium, nickel, gold, silver or the like can be used.

  Subsequently, the sputtered piezoelectric plate 72 is temporarily fixed to the fixed substrate 70 through the thermally foamable adhesive film. A marker hole (not shown) is formed in the fixed substrate 70 for aligning the bonding position with the flow path plate unit 60.

  A photosensitive film resist 76 is attached on the temporarily fixed piezoelectric plate 72. In this embodiment, a urethane film resist having a thickness of 50 μm is used. Thereafter, an exposure mask 78 having a pattern through which ultraviolet rays (UV) are transmitted only in the portions to be left as the piezoelectric actuator 42 and the remaining dummy plate 44 is separately prepared and attached to the film resist 76. The exposure mask 78 is patterned with reference to the marker hole of the fixed substrate 70.

  Next, as shown in FIG. 8B, UV irradiation is performed on the film resist 76 through the exposure mask 78, and then etching 84 is performed as shown in FIG. 8C. The etching solution used in the etching 84 has characteristics that do not remove the UV-irradiated portion and can reliably remove other portions, and for example, an aqueous sodium carbonate solution is used.

  After the etching, sand blasting is performed as shown in FIG. In the sandblasting process, the portion exposed by removing the film resist 76, that is, the portion corresponding to the separation slit 40 is surely ground and removed, and the portion (the piezoelectric actuator 42 and the remaining dummy plate 44) where the film resist 76 remains is removed. Is performed under conditions that prevent grinding. After sandblasting, the peripheral edge of the piezoelectric actuator 42 is sandblasted to form an adhesive escape portion 41.

  As shown in FIG. 7D, the piezoelectric unit 62 created in this way is bonded to the flow path plate unit 60 so that the opposite surface to which the fixed substrate 70 is bonded contacts the diaphragm 30. . Note that the piezoelectric unit 62 and the flow path plate unit 60 can be obtained by aligning a mark formed in the flow path plate unit 60 in advance with a marker hole previously opened in the fixed substrate 70 using an optical microscope, for example. Can be bonded with high accuracy. In addition, since the first and second electrode layers are formed as the electrode layers on both surfaces of the piezoelectric plate 72, the piezoelectric plate 72 is bonded to the vibration plate 30 that also serves as the common electrode with an adhesive. The electrode layer is electrically connected to the diaphragm 30, and therefore the piezoelectric actuator 42 and the diaphragm 30 are also electrically connected.

  Subsequently, as shown in FIG. 7E, the fixed substrate 70 is heated to reduce the adhesive strength of the heat-foamable adhesive film, and the fixed substrate 70 is peeled off, as shown in FIG. A solder ball 34 is formed for each piezoelectric actuator 42, and a circuit board 36 is bonded thereon.

  As described above, since the first and second electrode layers are formed on both surfaces of the piezoelectric plate 72, the second electrode layer, that is, the piezoelectric actuator 42 and the circuit board 36 are electrically connected. Further, the circuit board 36 and the diaphragm 30 are connected by a contact (not shown).

  Finally, by attaching an ink supply member or the like, the ink jet recording head 112 of this embodiment is completed.

  An ink jet recording apparatus 102 provided with the ink jet recording head 112 is shown in FIG.

  As shown in FIG. 13, the ink jet recording apparatus 102 includes a carriage 104 on which an ink jet recording head 112 is mounted, a main scanning mechanism 106 that scans the carriage 104 along the main scanning direction M, and a recording paper P in the sub scanning direction. A sub-scanning mechanism 108 that scans along S and a maintenance station 110 are provided.

  The ink jet recording head 112 is mounted on the carriage 104 so that the nozzle plate 21 on which the nozzles 10 are formed faces the recording paper P, and ejects ink droplets while moving in the main scanning direction M by the main scanning mechanism 106. Thus, an image is recorded on a certain band area BE of the recording paper P. When one movement in the main scanning direction is completed, the recording paper P is conveyed along the sub scanning direction S by the sub scanning mechanism 108, and the band 104 is recorded while the carriage 104 moves again in the main scanning direction M. . By repeating such an operation a plurality of times, image recording can be performed over the entire surface of the recording paper P.

  The inkjet recording head 112 may have a length over the entire width of the band region BE, and an image may be printed on the recording paper P without scanning the inkjet recording head 112 along the main scanning direction M. .

  Next, the operation of the ink jet recording head 112 will be described.

  As shown by an arrow Y in FIG. 1B, the ink introduced from the ink supply member into the ink jet recording head 112 is transferred to the common ink chamber 20, the planar communication path 16, the pressure chamber 14, and the nozzle communication chamber 12. Filled. In a state where ink is filled, for example, the piezoelectric actuator 42 is distorted by energizing the vibration plate 30 from the solder ball 34, the ink in the pressure chamber 14 is pressurized via the vibration plate 30, and the ink droplets from the nozzle 10. Is discharged.

  In the ink jet recording head 112, even when an adhesive is excessively applied to the adhesive surface of the piezoelectric actuator 42, the adhesive pushed out of the piezoelectric actuator 42 is accumulated inside the adhesive escape portion 41, and the piezoelectric actuator 42. It doesn't protrude outside. Accordingly, it is possible to effectively prevent variations in ink ejection characteristics due to the protruding adhesive and occurrence of crosstalk during ink ejection.

  Further, the piezoelectric actuator 42 has a shape in which the ratio of two diagonal lines is close to 1, that is, a piezoelectric drive portion 42A having a substantially rhombic planar shape in which the aspect ratio of the drive portion is close to 1, and a substantially fan-shaped electrode pad portion 42B. Are joined via a groove 41, and recessed portions 42C are formed at both ends of the electrode pad portion 42B, and a bent portion 42D is formed at a connection portion with the electrode pad portion 42B. Therefore, as shown in FIG. 3, the piezoelectric actuator 42 and the remaining dummy plate 44 can be arranged in a high-density matrix. In addition, the constriction of the connecting portion 42D makes it difficult to prevent the deformation due to the electrostrictive action of the rhombus-shaped portion 42B, so that high driving efficiency per unit area can be obtained, in other words, good and stable piezoelectric characteristics can be obtained. Can do.

  Further, since the groove width 40 is a constant width, the side etching amount is the same in any piezoelectric actuator 42 and the remaining dummy plate 44. Accordingly, high-precision processing is possible, and the dimensions of the piezoelectric actuator 42 and the remaining dummy plate 44 can be made uniform.

  As described above, since the inkjet recording head 112 has a shape in which the piezoelectric actuators 42 can be arranged in a matrix at a high density, the nozzles 10 can be formed in the nozzle plate 21 at a high density, and a high-quality image can be obtained. It is done.

  In addition, the shape of the piezoelectric actuator 42 is a good and stable shape that can obtain piezoelectric characteristics with little variation, so that a good and stable image can be obtained.

  Therefore, according to the ink jet recording apparatus 102, good and stable image formation can be performed at high speed.

  Inkjet recording in the present invention is not limited to recording characters and images on recording paper, and the liquid to be ejected is not limited to ink. Therefore, for example, an ink is discharged onto a polymer film or glass to create a color filter for display, or a welded solder is discharged onto a substrate to form a bump for mounting a component. The present invention can be applied to general droplet ejecting apparatuses used in general.

FIG. 1 is a cross-sectional perspective view showing the configuration of the ink jet recording head of the first embodiment. FIG. 2 is an enlarged plan view showing the configuration of the piezoelectric actuator and its vicinity in the ink jet recording head of Embodiment 1, and a sectional view showing a section of the piezoelectric actuator and its periphery cut along the plane AA in the enlarged plan view. It is. FIG. 3 is a plan view of the ink jet recording head of Embodiment 1 as viewed from the side where the piezoelectric actuator and the remaining dummy plate are bonded. FIG. 4 is an enlarged view of a part of the ink jet recording head shown in FIG. FIG. 5 is a cross-sectional view showing an example of an adhesive escape portion formed on the piezoelectric actuator. FIG. 6 is a cross-sectional view showing another example of the adhesive escape portion formed in the piezoelectric actuator. FIG. 7 is a process diagram illustrating a manufacturing process of the ink jet recording head of the first embodiment. FIG. 8 is a process diagram showing a manufacturing process of a piezoelectric actuator used in the ink jet recording head. FIG. 9 is a perspective view showing the configuration of an example of the ink jet recording apparatus of the present invention. FIG. 10 is a cross-sectional view showing a cross section when no adhesive escape portion is provided in the piezoelectric actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nozzle 12 Nozzle communication chamber 14 Pressure chamber 14A Wall surface 16 Planar direction communication path 18 Thickness direction communication path 20 Common ink chamber 30 Diaphragm 34 Solder ball 36 Circuit board 40 Separation slit 41 Adhesive goods escape part 42 Piezoelectric actuator 42A Piezoelectric drive part 44 Residual dummy plate 102 Inkjet recording device 112 Inkjet recording head

Claims (7)

An ink jet recording head that pressurizes ink in a pressure chamber by an electrostrictive action of a plate-like piezoelectric actuator and ejects the ink in droplets from a nozzle,
An ink jet recording head comprising: an adhesive escape portion that accommodates an adhesive over the entire circumference of an adhesive surface of the piezoelectric actuator that is bonded to the vibration plate.   The inkjet recording head according to claim 1, wherein the adhesive escape portion is a step having a certain width.   The inkjet recording head according to claim 1, wherein the adhesive escape portion is a chamfered portion having a constant width.   The inkjet recording head according to claim 1, wherein a remaining dummy plate to which no voltage is applied is bonded to the diaphragm between the piezoelectric actuators.   The inkjet according to any one of claims 1 to 4, wherein an adhesive escape portion is formed over the entire circumference of an adhesive surface of the remaining dummy plate that is bonded to the vibration plate. Recording head.   The inkjet recording head according to claim 5, wherein the piezoelectric actuator and the remaining dummy plate are formed in the same shape.   An ink jet recording apparatus comprising the ink jet recording head according to claim 1.

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