JP2006289643A - Image recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent foreign matter from entering a cavity unit, and to achieve reduction of part costs and simplification of manufacturing processes. <P>SOLUTION: An ink jet head 1 comprises the cavity unit 20 which includes a plurality of nozzles 23, a plurality of pressure chambers 24, a common ink chamber 25 for distributing ink to the plurality of pressure chambers 24, and an ink supply port 40 connected to the side of an ink supply source. The cavity unit 20 is formed by stacking a plurality of plates. The ink supply port 40 and the common ink chamber 25 are connected with each other by an ink supply passage 42 constituted by stacking the plurality of plates. The ink supply passage 42 includes a plurality of through holes 43 bored in each plate, and a rough surface 44 formed in at least one of opposite faces of the plates adjacent to each other in a stacking direction. The through holes 43 adjacent to each other in the stacking direction of the plates are made to communicate with each other via the rough surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inkjet head, and more particularly to a structure of a cavity unit to which ink from an ink supply source is supplied.

  As an ink jet head, there is known a structure in which a cavity unit in which a plurality of plates are formed by laminating a plurality of plates for an ink flow path and a piezoelectric actuator that applies discharge pressure to the ink in the cavity unit are known. Since ink is supplied from a separate ink supply source to such a cavity unit, an ink supply port that opens outward is usually provided on the flat plate surface of the cavity unit. When foreign matter such as dust contained in the ink flows into the cavity unit, a discharge failure is caused. In order to prevent this, a filter is attached to the outside of the ink supply port.

  However, in the form in which the filter is attached to the ink supply port, there is a problem that the number of manufacturing steps increases because a step of bonding the filter is required in addition to the step of bonding the plate constituting the cavity unit. Further, the filter is a minute part, and the bonding area is narrow, so that the bonding work is difficult.

Accordingly, as disclosed in Patent Document 1, the present inventor has developed a technique for providing a filter function in the ink flow path inside the cavity unit without attaching a filter to the outside of the ink supply port. In Patent Document 1, a plurality of communication holes serving as ink flow paths are provided in a plurality of plates of the cavity unit, and the centers of the communication holes adjacent to each other in the stacking direction of the plates are displaced. Or less. Thereby, the overlapping of the communication holes is made to function as a filter for removing foreign matters in the ink.
JP 2001-328264 A (see FIGS. 2 and 3)

  However, in order for the overlapping of communication holes adjacent in the stacking direction to function as a filter, it is necessary to align the overlap so that the overlap is about the size of the filter mesh (about 15 μm in Patent Document 1). When the positions of the opposing surfaces of the plates are displaced, the size of the filter mesh changes, and the filter performance differs for each cavity unit. Therefore, in order to align the opposing surfaces of each plate, a highly accurate operation is required, which causes a problem that the process becomes complicated.

  An object of the present invention is to solve the above-described problems, and to provide an ink jet head that can reliably prevent foreign matters from being mixed into a cavity unit, reduce component costs, and simplify a manufacturing process. It is what.

  In order to achieve the above object, an ink jet head according to a first aspect of the present invention includes a plurality of nozzles for ejecting ink, a plurality of pressure chambers provided corresponding to each nozzle, and ink in a plurality of pressure chambers. In an inkjet head having a common ink chamber for distribution and an ink supply port connected to an ink supply source side and a cavity unit formed by stacking a plurality of plates, the ink supply port and the ink supply port The common ink chamber is connected by an ink supply path configured by laminating a plurality of plates. The ink supply path includes a plurality of through-holes per plate and plates adjacent in the stacking direction. A through-hole adjacent to each other in the laminating direction of the plates through the rough surface. And it is characterized in that it is configured to passing.

  According to a second aspect of the present invention, in the ink jet head according to the first aspect, the plurality of plates forming the cavity unit are at least a cavity plate having the pressure chamber and a manifold plate having the common ink chamber. And a spacer plate having a connection flow path connecting the pressure chamber and the common ink chamber, and the through hole is formed at a position that does not oppose the cavity plate and the spacer plate, and the rough surface Is formed on at least one of the opposing surfaces of the cavity plate and the spacer plate.

  According to a third aspect of the present invention, in the ink jet head according to the second aspect, the spacer plate is formed by laminating a plurality of plates, and the through holes are located at positions that do not face each other. The rough surface is formed on at least one of the opposing surfaces of the plates.

  The invention according to claim 4 is the inkjet head according to any one of claims 1 to 3, wherein the rough surface has a surface roughness Rz of 0.01 to 0.02 mm. To do.

  According to a fifth aspect of the present invention, in the ink jet head according to any one of the first to fourth aspects, the rough surface is formed by blasting, pressing or etching.

  According to a sixth aspect of the present invention, in the ink jet head according to any one of the first to fifth aspects, the plate constituting the ink supply path is made of metal, and the through hole is formed by etching. It is characterized by this.

  According to the first aspect of the present invention, since the rough surface is formed on at least one of the opposing surfaces of the plates in the ink supply path, the surfaces adjacent to each other in the stacking direction do not adhere to each other. A gap corresponding to the unevenness of the rough surface is formed at the interface. Therefore, the ink flowing from the ink supply port to the common ink chamber moves from the through hole to the through hole of the next plate through the rough surface gap. As a result, foreign matters contained in the ink are removed when passing through the rough surface, and the rough surface functions as a filter.

  Since the performance of the filter is defined by the surface roughness of the rough surface, even if the opposing surfaces of the plates are slightly displaced in the step of bonding the plates constituting the cavity unit, the filter performance is not affected. Therefore, it is possible to eliminate manufacturing variations in filter performance for each cavity unit.

  Further, since the filter function is provided inside the cavity unit, a conventional process for separately bonding the filter to the outer surface of the cavity unit is not required.

  According to the second aspect of the present invention, since the through holes are formed in the cavity plate and the spacer plate at positions that do not face each other, the ink that has exited the through holes of the cavity plate has not yet reached the through holes of the spacer plate. In addition, since it always passes through the rough surface of the cavity plate and the spacer plate, the filter function by the rough surface is reliably exhibited.

  According to the invention described in claim 3, since the spacer plate is formed by laminating a plurality of plates, the rough surface is provided between the cavity plate and the spacer plate and between the spacer plates. It will be. Thereby, since the rough surface which exhibits a filter function is formed in a multilayer structure, filter performance can be improved.

  According to the fourth aspect of the present invention, the rough surface has a surface roughness within a specified range, so that a filter effect suitable for removing foreign matters in the ink can be surely exhibited.

  According to the invention described in claim 5, since the blasting, pressing or etching process is used, the rough surface can be easily processed. In the case of blasting, the rough surface is defined by the abrasive grains used. It can be surely finished.

  According to the sixth aspect of the present invention, the other etching processes for each plate and the etching process for the through holes can be performed in the same process, and there is no need to add a process for forming the ink supply path. .

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view of an inkjet head according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the inkjet head, and FIG. 3A is a cross-sectional view taken along line IIIa-IIIa in FIG. 3B is a cross-sectional view taken along the line IIIb-IIIb in FIG. 1, and FIG. 4 is a schematic enlarged view of the ink supply path.

  FIG. 1 is a perspective view of a cavity unit 20, a piezoelectric actuator 21, and a flexible flat cable 22 in a piezoelectric inkjet head 1 according to an embodiment of the present invention. The cavity unit 20 is composed of a plurality of metal plates. A plate type piezoelectric actuator 21 is joined, and a flexible flat cable 22 for connection to an external device is overlapped and joined to the upper surface of the plate type piezoelectric actuator 21. Then, it is assumed that ink is ejected downward from the nozzle 23 opened on the lower surface side of the cavity unit 20 (see FIG. 3B).

  As shown in FIG. 2, the cavity unit 20 is composed of a total of seven thin plates including a nozzle plate 31, a base plate 32, a manifold plate 33, three spacer plates 35a, 35b, 35c, and a cavity plate 36, respectively. It has a structure of lap joint.

  In the embodiment, each of the plates 31 to 36 has a thickness of about 50 to 150 μm, the nozzle plate 31 is made of synthetic resin such as polyimide, and the other plates 32 to 36 are made of 42% nickel alloy steel plate. The nozzle plate 31 has a plurality of nozzles 23 for discharging ink having a minute diameter (about 20 to 23 μm) at minute intervals. The nozzles 23 are arranged in two rows parallel to the long side direction (X direction) of the nozzle plate 31.

  In the cavity plate 36, as shown in FIGS. 2 and 3B, a plurality of pressure chambers 24 are arranged in two rows parallel to the long side of the cavity plate 36 (the X direction). In the embodiment, each of the pressure chambers 24 is formed in an elongated shape in plan view, and the longitudinal direction thereof is bored along the short side direction (Y direction) of the cavity plate 36, and one end portion in the longitudinal direction is a nozzle. The other end communicates with a common ink chamber 25 described later.

  The front end of each pressure chamber 24 communicates with each nozzle 23 in the nozzle plate 30 through a small-diameter communication hole 26 formed in three spacer plates, a manifold plate 33, and a base plate 32. Yes.

  In each of the spacer plates 35c, 35b, 35a adjacent to the lower surface of the cavity plate 36, a connection channel 28 connected to the other end of each pressure chamber 24 is formed through each plate. Of the three spacer plates 35c, 35b, 35a, the connection channel 28 of the spacer plate 35a adjacent to the manifold plate 33 has a smaller diameter (cross-sectional area) than the connection channel 28 of the other two spacer plates 35b, 35c. ), And functions as a narrowed portion 28a having a larger flow path resistance between a common ink chamber 25 and a pressure chamber 24, which will be described later.

  The manifold plate 33 is formed with two common ink chambers 25 penetrating the plate thickness so as to extend along each row of the nozzles 23 along the long side direction (X direction). That is, as shown in FIGS. 2 and 3, by covering the upper surface of the manifold plate 33 with the spacer plate 35a and covering the lower surface with the base plate 32, a total of two common ink chambers (manifold chambers) 25 are hermetically sealed. It is formed. Each common ink chamber 25 overlaps with a part of the pressure chamber 24 and extends in the row direction of the pressure chambers 24 (row direction of the nozzles 23) when viewed in plan from the stacking direction of the plates.

  As shown in FIGS. 2 and 3 (a), the cavity plate 36 and the three spacer plates 35a to 35c are respectively provided at two locations corresponding to the upper and lower positions on one end of the short side. Ink supply port 40 is provided. Ink from an ink supply source (not shown) is supplied into the cavity unit 20 via a joint member 41 attached to these ink supply ports 40.

  The ink supply port 40 and one end of the common ink chamber 25 are connected by an ink supply path 42, and the ink supply path 42 is a total of four plates including a cavity plate 36 and three spacer plates 35 a to 35 c. It is formed across. The ink supply path 42 has a plurality of through-holes 43 formed for each plate and a rough surface 44 formed on at least one of the opposing surfaces of the plates adjacent in the stacking direction. In this embodiment, only the region of the ink supply path 42 on the upper side of the opposing surfaces of the plates, that is, the lower surfaces of the cavity plate 36 and the spacer plates 35a and 35b, is rougher than other regions on the same plane. A rough surface 44 having a large thickness is formed. The surface roughness of the rough surface 44 is sufficiently smaller than the diameter of the nozzle 23, for example, Rz is preferably 0.01 to 0.02 mm, and the hole diameter of the through hole 43 is 50 μm or more and 500 μm or less. desirable. The rough surface 44 may be provided on the lower side of the opposing surfaces of the plates or may be provided on both the upper and lower sides by blasting, pressing, or etching.

  Since each plate is made of metal as described above, the processing of the through hole 43 is performed together with the processing of the pressure chamber 24 in the cavity plate 36 and the processing of the communication hole 26 and the connection channel 28 in the spacer plates 35a to 35c. They can be formed simultaneously in the etching process.

  The through holes 43 are provided at positions where the through holes 43 adjacent to each other in the stacking direction do not face each other, in other words, at positions where they do not overlap in a plan view from the stacking direction. Thus, the ink supplied from the ink supply port 40 always passes through the rough surface 44 on the way from the through hole 43 to the next (closer to the common ink chamber 25) through the through hole 43 (ink supply path 42). One path of ink passing through is indicated by arrow A in FIG. The rough surface 44 functions as a filter, and foreign matters such as dust contained in the ink are filtered when passing through the irregularities of the rough surface 44 as shown in FIG. Removed before reaching. The ink from which the foreign matter has been removed is supplied to the common ink chamber 25, and then, as shown in FIG. 3B, each pressure of the cavity plate 36 via the connection flow path 28 of the spacer plates 35a, 35b, and 35c. It is distributed and supplied to the chamber 24. Then, the ink passes through the communication hole 26 from each pressure chamber 24 and reaches the nozzle 23 corresponding to the pressure chamber 24.

  On the other hand, the piezoelectric actuator 21 is a plurality of piezoelectric sheets each having a thickness of about 30 μm as shown in FIG. 3B, similarly to the known one disclosed in JP-A-4-341853. In the structure in which 51 to 53 are laminated, the upper surface (wide surface) of a predetermined number of even-numbered piezoelectric sheets 52 from the bottom of each piezoelectric sheet is provided for each location corresponding to each pressure chamber 24 in the cavity unit 20. Narrow individual electrodes 54 are formed in a row along the long side direction (X direction). A common electrode 55 common to the plurality of pressure chambers 24 is formed on the upper surface (wide surface) of a predetermined number of odd-numbered piezoelectric sheets 51 from below, and the upper surface of the uppermost sheet is As the surface electrode 56 (see FIG. 1), a surface electrode electrically connected to each of the individual electrodes corresponding to the stacking direction and a surface electrode electrically connected to the common electrode are provided. It has been.

  As is well known, by applying a high voltage between the individual electrode 54 and the common electrode 55, the portion of the piezoelectric sheet positioned between both electrodes is polarized and formed as an active portion.

  In the above configuration, since the ink supply path 42 itself connecting the ink supply port 40 and the common ink chamber 25 in the cavity unit 20 functions as a filter, the filter is purposely stuck to the outer surface of the cavity unit 20 as in the past. There is no need, and the cavity unit 20 can be provided with a filter function by simply laminating and bonding the plates constituting the cavity unit 20.

  The ink supply path 42 uses the surface roughness of the rough surface 44 formed on the opposed surfaces of the plates instead of the through-holes 43 to remove foreign matters. Even if a slight displacement occurs in the surface direction, the removal performance of the rough surface 44 against foreign matters is not affected. Therefore, manufacturing variations in filter performance for each cavity unit 20 can be eliminated.

  In the above embodiment, the ink supply path 42 is provided in the cavity plate 36 and the three spacer plates 35a to 35c. However, the number of spacer plates is not limited to this, but the ink supply path is not limited to this. The filter performance can be improved by increasing the number of plates to be formed and multilayering the rough surface 44.

1 is a perspective view of an inkjet head according to an embodiment of the present invention. It is a disassembled perspective view of an inkjet head. (A) Cross-sectional view taken along line IIIa-IIIa in FIG. 1 with the joint member attached, (b) is a cross-sectional view taken along line IIIb-IIIb in FIG. FIG. 3 is a schematic enlarged view of an ink supply path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 20 Cavity unit 21 Piezoelectric actuator 22 Flexible flat cable 23 Nozzle 24 Pressure chamber 25 Common ink chamber 26 Communication hole 28 Connection flow path 31 Nozzle plate 32 Base plate 33 Manifold plate 35a, 35b, 35c Spacer plate 36 Cavity plate 40 Ink supply Port 42 Ink supply path 43 Through hole 44 Rough surface

Claims (6)

A plurality of nozzles for discharging ink, a plurality of pressure chambers provided corresponding to each nozzle, a common ink chamber for distributing ink to the plurality of pressure chambers, and an ink supply port connected to the ink supply source side In an inkjet head provided with a cavity unit formed by laminating a plurality of plates
The ink supply port and the common ink chamber are connected by an ink supply path configured by stacking a plurality of plates,
The ink supply path includes a plurality of through-holes per plate and a rough surface formed on at least one of opposing surfaces of the plates adjacent in the stacking direction,
An inkjet head characterized in that through holes adjacent in the stacking direction of the plates communicate with each other through the rough surface. The plurality of plates forming the cavity unit include a cavity plate having at least the pressure chamber, a manifold plate having the common ink chamber, and a spacer plate having a connection flow path connecting the pressure chamber and the common ink chamber. And
The through hole is formed at a position where the cavity plate and the spacer plate are not opposed to each other, and the rough surface is formed on at least one of the opposed surfaces of the cavity plate and the spacer plate. The inkjet head according to claim 1.   The spacer plate is formed by laminating a plurality of plates, the through hole is formed at a position that does not face each other, and the rough surface is formed on at least one of the facing surfaces of each plate. The inkjet head according to claim 2, wherein the inkjet head is provided.   The inkjet head according to any one of claims 1 to 3, wherein the rough surface has a surface roughness Rz of 0.01 to 0.02 mm.   The inkjet head according to claim 1, wherein the rough surface is formed by blasting, pressing, or etching.   The ink jet head according to claim 1, wherein the plate constituting the ink supply path is made of metal, and the through hole is formed by etching.

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