JPH05286142A - Ink jet head and production thereof - Google Patents

Abstract

PURPOSE:To provide a multi-nozzle ink jet head used in an ink jet printer and injecting ink from nozzles under a stable injection condition without exerting the effect of pressure generating means on respective pressure chambers to perform high-grade recording by a reduced number of processes. CONSTITUTION:An ink jet head has a double-layered structure of a surface plate 10 and a rear plate 20 and grooves 25 are formed on the surface of the rear plate 20 so as to be arranged to the peripheries of the positions corresponding to respective pressure chambers 40 in the arranging surfaces of pressure generating means 70 and, thereafter, a sheet like piezoelectric element 70a is formed on the entire surface of the rear plate 20 so as to cover all of the pressure chambers 40 on a head and cut along the grooves 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-nozzle inkjet head used in an inkjet printer and a method for manufacturing the same.

[0002]

2. Description of the Related Art A multi-nozzle inkjet head used in a drop-on-demand inkjet recording apparatus that uses a piezoelectric element and selectively ejects ink in a pressure chamber by its displacement to record on a recording medium is In recent years, miniaturization has advanced and sophisticated products have been proposed.

For example, there is a multi-nozzle ink jet head shown in FIGS. 5 and 6 proposed in Japanese Patent Laid-Open No. 2-187352. FIG. 5 is a side view of the multi-nozzle inkjet head, and FIG. 6 shows a main part of the AA cross section in FIG. In FIG. 5, 101 is the inkjet head, 102 is a nozzle, 103 is an ink supply port, 10
4 is an ink supply path, 105 is a pressure chamber, and 106 is a nozzle 1.
An ink flow path to 02, and 107 a piezoelectric element.

Further, in FIG. 6, 111 is a substrate and 11
Reference numeral 2 denotes a diaphragm, and 113 denotes a groove formed by cutting. With the miniaturization of the inkjet head, the pressure chamber 10
Since the distance K between the five becomes narrower, the driving of the piezoelectric element 107 affects the adjacent pressure chambers 105, and the stability of ink ejection is impaired.

The above ink jet head has been proposed to solve the above problems. That is, in the inkjet head, after a sheet-shaped piezoelectric element is bonded onto the vibration plate 112, the boundary portion of each pressure chamber 105 is cut with a diamond wheel to form the groove 113, and the vibration plate between the pressure chambers 105 is formed. The thickness of 112 is half that before cutting.

According to the proposal, the thickness of the vibrating plate 112 between the pressure chambers 105 is halved before cutting, and as a result, the influence of the piezoelectric element 107 on the adjacent pressure chambers 105 is ⅛. It is possible to stably eject the ink.

[0007]

However, even the above method still has the following problems to be solved. (1) In addition, in the above inkjet head, when cutting the boundary between the pressure chambers 105 to form a groove,
In order to unify the thickness of the diaphragm 112 between the pressure chambers 105 to a constant value, a very accurate and expensive cutter is required. Alternatively, highly skilled work is required and the man-hours are large.

(2) When a groove is formed at the boundary between the pressure chambers 105, the depth of the groove varies, so that the thickness of the vibrating plate 112 varies at the location where the groove is formed.
Since this variation affects the flight conditions of ejected ink between nozzles, it is difficult to obtain high-quality inkjet recording. (3) Therefore, in order to obtain high quality ink jet recording, the thickness of the diaphragm 112 at the location where each groove is formed for each head is at least within a predetermined specified value. It is necessary. That is, after the head is completed, an inspection for confirming the thickness of the vibrating plate 112 at the place where the groove is formed is indispensable. In addition, the smaller the head, the more accurate inspection is required,
Inspection man-hours increase.

(4) In order to obtain high quality recording with the above ink jet head, it is necessary to adjust the voltage value and pulse width applied to the piezoelectric element 107 for each pressure chamber 105. That is, it is necessary to adjust the applied voltage value and the pulse width each time the head is replaced not only when the inkjet recording apparatus is shipped, but also in the field and the like, which increases the number of adjustment steps.

The present invention has been made to solve the above-mentioned problems, and each pressure chamber ejects ink from a nozzle under stable ejection conditions without being affected by an adjacent pressure generating means. It is an object of the present invention to provide an inkjet head capable of high-quality recording with a small number of steps.

[0011]

As shown in FIG. 2, the ink jet head according to the present invention is characterized in that grooves 25 are formed in advance on the surface of the back layer plate 20 around each pressure chamber 40. To do. Then, as shown in FIG. 4, one sheet-shaped piezoelectric element 70 a covering the entire plurality of pressure chambers 40 is attached to the back layer plate 20 having the groove 25, and then the groove 25 is provided in the groove 25. By cutting the sheet-shaped piezoelectric element 70a along the above, the pressure generating means 70 corresponding to each pressure chamber 40 was formed.

The groove 25 may satisfy the following conditions. (A) The depth of the groove 25 should be a depth at least capable of absorbing the variation in the cutting depth when the sheet-shaped piezoelectric element 70a is cut. (B) The accuracy of the variation in the depth of the groove 25 is a necessary and sufficient numerical value so as to reduce the influence on the adjacent pressure chambers 40.

The structure of the ink jet head according to the present invention may be one sheet or two or more sheets.

[0014]

In the ink jet head according to the present invention, the above-mentioned problem is solved by forming the above-mentioned groove 25 on the surface of the back layer plate 20 around the position corresponding to each pressure chamber 40 in advance. In addition to that, the following effects can be obtained. (A) When the sheet-shaped piezoelectric element 70a is cut, no special precision is required for the cutting depth of the blade.

Therefore, a specially accurate cutter and highly skilled work are not required, and the number of steps can be reduced. (B) As the accuracy of the variation in the thickness of the back layer plate 20 in the portion where the groove 25 is formed, the accuracy at the time of manufacturing the back layer plate 20 can be secured. For example, when the groove is provided by etching or the like, the variation in the depth of the groove 25 can be suppressed to an accuracy of ± 2 μm or less.

Therefore, variations in the jetting speed of the ejected ink between the nozzles due to the adjacent pressure generating means 70 can be suppressed within a narrow range, and high quality ink jet recording can be obtained. (C) The inspection of the depth of each groove can be simplified. (D) Further, it is not necessary to adjust the voltage value or pulse width applied to each pressure generating means 70.

That is, it becomes unnecessary to adjust the voltage value and the pulse width applied to each pressure generating means 70, which is required not only when the ink jet recording apparatus is shipped but also when the head is replaced in the field or the like.

[0018]

EXAMPLE An example of an ink jet head according to the present invention is shown in FIGS. 2 is a sectional view of the inkjet head according to the present invention taken along the line BB in FIG.
It is the conceptual diagram which expanded the principal part. As shown in FIG. 2, in the case of the present embodiment, the head body is composed of the surface layer plate 10 and the back layer plate 20, and the plurality of nozzles 30 are provided through the surface layer plate 10 by etching. In addition, a plurality of pressure chambers 40 and a common ink chamber 5 that supplies ink to the pressure chambers 40.
0 (shown in FIGS. 3 and 4) is formed by etching the back layer plate 20. Further, in the back layer plate 20, a groove 25 is formed by etching at a position corresponding to the periphery of each pressure chamber 40 on the surface opposite to the surface on which the pressure chamber 40, the common ink chamber 50 and the like are formed. ing.

The plurality of pressure generating means 70 are formed by adhering the sheet-shaped piezoelectric element 70a to the back layer plate 20 side and then cutting it along the groove 25. A dicing saw (manufactured by Disco: DAD-2H / 6T) was used for cutting. FIG. 3 is a diagram of the inkjet head according to the present embodiment as viewed from the surface layer plate 10 side. As shown in FIG. 3, a plurality of nozzles 30 are formed on the surface layer plate 10 side. In this embodiment, the head size is 8 mm in length, 20 mm in width, and 0.35 mm in thickness (surface layer plate: 0.2 mm, back layer plate:
Realization of miniaturization of 0.15 mm).

FIG. 4 is a view of the ink jet head according to this embodiment as viewed from the back layer plate 20 side. As shown in FIG. 4, after a sheet-shaped piezoelectric element 70a is adhered to the surface of the back layer plate 20, the sheet-shaped piezoelectric element 70a is cut vertically and horizontally along the groove 25 to form a plurality of pressure generating means 70. Formed. As described above, in the inkjet head according to the present invention, the total pressure generating means 70 for one head can be formed at the correct position with a small number of steps. In this embodiment, the sheet-shaped piezoelectric element 70a is cut vertically and horizontally along the groove 25 to form the pressure generating means 70, and as a result, the positional displacement accuracy of the pressure generating means 70 is about ± 5 μm. It was realized.

Further, by forming the groove 25 by etching, the accuracy of the depth of the groove 25 could be suppressed to ± 2 μm or less. That is, the accuracy of the thickness of the back layer plate 20 at the boundary between the pressure chambers 40 is also ± 2 μm or less, and it is possible to ignore the variation of the influence from the adjacent pressure generating means 70. As a result, the amount of ink particles ejected from each nozzle and the ejection speed were stable, and an inkjet head capable of high-quality recording was obtained.

By the way, in the ink jet head of this embodiment, the sheet-shaped piezoelectric element 7 is formed without forming the groove 25.
0a was adhered to the back layer plate 20 side, and the experiment of the above cutting work was conducted using the above dicing saw. However, due to the blade setting accuracy of the dicing saw and the abrasion of the blade for each cutting process, It was confirmed that the cutting depth had a variation of ± 10 μm or more. Further, a recording experiment was conducted using the ink jet head, and the flying speed of ink particles between nozzles was varied, the positional accuracy of dots on the recording paper was reduced, or the dot diameter was varied. As compared with the recording result by the ink jet head according to the present invention, which was manufactured by forming the above-mentioned recording medium, the deterioration of the recording quality was recognized.

Next, the manufacturing procedure of the ink jet head according to the present invention will be described. 1a to 1g show a manufacturing procedure of an inkjet head according to the present invention, and correspond to manufacturing procedures (a) to (g) described below, respectively. (A) Preparation of surface layer plate 10. The surface layer plate 10 is a photosensitive glass (made by Hoya Corporation: PEG
3) is used to form a plurality of nozzles by etching. The surface layer plate 10 has a thickness of 200 μm and each nozzle has a diameter of 50.
μm.

The surface layer plate 10 may be manufactured by electroforming. (B) Creation of the back layer plate 20. The back layer plate 20 is also formed by etching the same photosensitive glass as the front layer plate 10 to form pressure chambers 40 at positions corresponding to the nozzles, and a common ink chamber 50 communicating with the pressure chambers 40.
Ink flow paths are formed. The thickness of the back layer plate 20 is 150
μm, and the etching depth was 50 μm.

Further, in the back layer plate 20, grooves 25 are formed around each pressure chamber 40 on the surface opposite to the surface on which the pressure chamber 40 and the common ink chamber 50 are formed. The etching depth was 30 μm. (C) Adhesion between the surface layer plate 10 and the back layer plate 20. The front layer board 10 and the back layer board 20 are adhered by an anaerobic adhesive (LI210 manufactured by Nippon Loctite Co., Ltd.).

(D) Formation of electrode 80. Silver paste (manufactured by Tokuriki Kagaku Kenkyusho: Silvest PS707) is applied to the surface of the back layer plate 20, and the electrode 80 is formed by baking at a temperature of 160 ° C. for 1 hour. The back layer plate 2
When a conductor such as stainless steel (SUS430) is used as the 0 material, it is not necessary to form the main electrode 80.

(E) Adhesion of the sheet-shaped piezoelectric element 70a. A sheet-shaped piezoelectric element 70a (manufactured by Tokin KK: outer shape = 6 × 15 × 0.1 mm) is bonded onto the electrode 80 with an epoxy adhesive (manufactured by Ciba-Geigy: AW106, HV953U) and cured. Environmental temperature is 80 ℃, time required is 3
Time is optimal.

(F) Formation of pressure generating means 70. The sheet-shaped piezoelectric element 70a is cut along the groove 25 with a dicing saw (Disco: DAD-2H / 6T). In this example, cutting was performed using a blade having a thickness of 30 μm. When this work is completed, as shown in FIG. 4, the piezoelectric element 70b, which is the residual portion obtained by cutting the sheet-shaped piezoelectric element 70a, remains, but since the pressure generating means 70 is completely separated by the cutting, the pressure It has no influence on the generating means 70. Therefore, the remaining piezoelectric element 7
0b may or may not be removed. In this embodiment, the piezoelectric element 70b was not removed for the purpose of reducing the number of steps.

In FIGS. 2 and 4 of the present embodiment, the groove width after cutting is intentionally drawn large in order to facilitate understanding of the positional relationship between the pressure generating means 70 and the pressure chamber 40 after cutting. .. (G) Attaching the lead wire 85a. The flexible printed board 85 is attached to the head, and the lead wire 85a from the flexible printed board 85 is connected to each pressure generating means 70 by wire bonding.

The above process sequence is an example.
For example, the procedure and order may be changed appropriately in consideration of the convenience and efficiency of the work, such as performing the bonding work of (c) last.

[0031]

The ink jet head according to the present invention is
A method in which a groove 25 is formed in advance around the position corresponding to each pressure chamber 40 on the surface of the back layer plate 20, a sheet-shaped piezoelectric element 70a is attached, and then cut out along the groove 25. By forming the pressure generating means 70 at
The following effects can be obtained.

(1) When the sheet-shaped piezoelectric element 70a is cut, no special precision with respect to the cutting depth is required, so that a particularly precise cutter and highly skilled work are not required, and the number of steps can be reduced. .. (2) When the groove 25 is formed by etching or the like, the groove 25
Since the variation of the depth of the ink can be suppressed to an accuracy of ± 2 μm or less, the ink flying conditions for each nozzle are stable,
High quality ink jet recording can be obtained.

(3) The inspection of the depth of each groove can be simplified. (4) It is not necessary to adjust the voltage value or pulse width applied to each pressure generating means 70, which is required not only when the inkjet recording apparatus is shipped but also when the head is replaced in the field or the like.

[Brief description of drawings]

FIG. 1 is a procedure for manufacturing an inkjet head according to the present invention.

FIG. 2 is a sectional view of an inkjet head according to the present invention (main part of BB section in FIG. 3).

FIG. 3 is a diagram of an inkjet head according to the present invention viewed from the surface layer side.

FIG. 4 is a view of an inkjet head according to the present invention as viewed from the back layer side.

FIG. 5 is a side view of a conventional inkjet head.

FIG. 6 is a cross-sectional view of a conventional inkjet head (main part of cross section AA in FIG. 5).

[Explanation of symbols]

 10 surface layer plate 20 back layer plate 25 groove provided on back layer plate 30 nozzle 40 pressure chamber 70 pressure generating means 70a sheet-shaped piezoelectric element 70b piezoelectric element left after cutting 85 flexible printed board

Claims (3)

[Claims] 1. A plurality of nozzles (3) for ejecting ink.
0), a plurality of pressure chambers (40) communicating with the respective nozzles (30), substrates (10, 20) forming a part of the respective pressure chambers (40), and the substrates (10, 20). A multi-nozzle inkjet head that is disposed on the surface of the substrate and has a pressure generating means (70) for applying a pressure to each of the pressure chambers (40). 70) After forming a groove (25) around the position corresponding to each pressure chamber (40) on the arrangement surface, the substrate (10,
20) the material (71) on the pressure chambers (40)
The material (71) over the entire surface so as to cover the groove (2
5) A method for manufacturing a multi-nozzle inkjet head, characterized by being cut along the line 5). 2. A plurality of nozzles (3) for ejecting ink.
0), a plurality of pressure chambers (40) communicating with the respective nozzles (30), substrates (10, 20) forming a part of the respective pressure chambers (40), and the substrates (10, 20). A multi-nozzle inkjet head that is disposed on the surface of the substrate and has a pressure generating means (70) for applying a pressure to each of the pressure chambers (40), the surface of the substrate (10, 20) being the pressure generating means (70). 70) After forming a groove (25) around the position corresponding to each pressure chamber (40) on the arrangement surface, the substrate (10,
20), a sheet-shaped piezoelectric element (70a) is formed on the entire surface so as to cover the plurality of pressure chambers (40), and the sheet-shaped piezoelectric element (70a) is formed along the groove (25). A method for manufacturing a multi-nozzle inkjet head, characterized by being cut. 3. A plurality of nozzles (3) for ejecting ink.
0), a plurality of pressure chambers (40) communicating with the respective nozzles (30), substrates (10, 20) forming a part of the respective pressure chambers (40), and the substrates (10, 20). A multi-nozzle inkjet head that is disposed on the surface of the substrate and has a pressure generating means (70) for applying a pressure to each of the pressure chambers (40), the surface of the substrate (10, 20) being the pressure generating means (70). 70) After forming a groove (25) around the position corresponding to each pressure chamber (40) on the arrangement surface, the substrate (10,
20), a sheet-shaped piezoelectric element (70a) is formed on the entire surface so as to cover the plurality of pressure chambers (40), and the sheet-shaped piezoelectric element (70a) is formed along the groove (25). A multi-nozzle inkjet head characterized by being cut.