JP2000033699A - On-demand multinozzle ink jet head and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head of thin plates laminated through adhesive in which an air pocket is not produced between plates and projection of adhesive is regulated not to cause incomplete ejection of ink drop. SOLUTION: At least an orifice plate 11 and a chamber plate 13 are bonded through adhesive 31a while satisfying conditions of d1+2xL1<L2, wherein d1 is the diameter of inlet hole of the orifice plate, L1 is the projecting quantity of adhesive and L2 is the shortest width of chamber of the chamber plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in performance of an ink jet head, and more particularly, to an improvement in landing accuracy of ink ejected from a nozzle.

[0002]

2. Description of the Related Art Inkjet printheads have been formed by laminating thin plates such as stainless steel plates. Nickel bonding has been the mainstream in the past, but the bonding temperature of nickel was 700 ° C. to 900 ° C. Therefore, it was difficult to ensure the positional accuracy of the nozzle.

There is also a method of laminating plates using an adhesive, but there are also problems with the method by adhesion, such as the adhesive being attacked by ink and the bonding technique being incomplete.

[0004]

FIG. 3 and FIG. 4 show examples of defective bonding by the conventional bonding technique.

FIG. 3 shows that the adhesive was not sufficiently applied.
Alternatively, air pockets 33 are generated between the plates due to insufficient pressing force. If air pockets are formed in the pressurized chamber, it becomes extremely difficult to remove residual air in the pressurized chamber even if the nozzle is purged.

FIG. 4 shows the state in which the adhesive between the orifice plate and the chamber plate has protruded and has caught the orifice hole. When ink droplets are generated in this state, the ink droplets are distorted and fly out of the orifice hole,
The print dots are broken or the paper placement position accuracy is extremely poor.

An object of the present invention is to provide a method for solving the above-mentioned problems and enabling lamination of thin plates with an adhesive.

[0008]

To achieve the above object, the present invention provides a chamber plate forming a pressurized chamber,
A restrictor plate forming a pressurized chamber together with the chamber plate, and also forming a restrictor flow path for supplying ink to the pressurized chamber; and a piezoelectric element for generating pressure fluctuation in the pressurized chamber by applying an electric signal. A diaphragm plate that forms at least a part of the wall surface of the pressure chamber and is connected to the piezoelectric element with an elastic material, and a plate that forms a common ink supply path that supplies ink to the restrictor;
In an on-demand type multi-nozzle inkjet head having a plurality of nozzles constituted by orifice plates having orifice holes for ejecting ink droplets from a pressurizing chamber, at least the orifice plate and the chamber plate are bonded with an adhesive, This is achieved by satisfying the following conditions. Here, the diameter of the inlet hole of the orifice plate is d1, the amount of the adhesive protruding is L1, and the shortest width of the pressure chamber of the chamber plate is L2.

[0009]

(Equation 2)

The orifice plate is formed by electroforming, and the opening on the side of the pressurizing chamber is widened in a trumpet shape with respect to the outer opening of the orifice hole.
Alternatively, it may be formed by press working, and the opening on the pressurizing chamber side may be widened in a tapered shape with respect to the outer opening of the orifice hole. Further, the amount of the adhesive protruding between the orifice plate and the chamber plate may be restricted to 10 μm to 100 μm. Then, in order to control the amount of protrusion of the adhesive, the adhesive material is diluted with an organic solvent,
Then, it may be applied to each plate.

[0011]

FIG. 1 is a sectional view showing one nozzle of an ink jet head according to the present invention.

In the drawing, 11 is an orifice plate,
Reference numeral 12 denotes an orifice hole formed in the orifice plate, 13 denotes a chamber plate constituting a pressurizing chamber 16, 1
4 is a restrictor plate constituting the restrictor flow path 17, 15 is a diaphragm plate, 20 is a piezoelectric element,
Reference numeral 21 denotes the displacement of the piezoelectric element 20 for the diaphragm plate 15.
An elastic body for transmitting the pressure to the pressurizing chamber 16 through the air gap, 31a is an adhesive layer generated between the orifice plate 11 and the chamber plate 13, 31b is an adhesive layer between the chamber plate and the restrictor plate 14, and 31c is a restrictor. An adhesive layer 32 between the plate and the diaphragm plate 15 is an adhesive protruding portion which protrudes into the chamber 16 from the adhesive layer 31a.

Here, the opening of the orifice hole 12 on the side of the pressurizing chamber 16 is open like a trumpet, and the diameter thereof is d1, while the diameter of the outer opening of the orifice hole 12 is d2. , D1> d2.

When the orifice plate 11 is manufactured by electroforming (electroforming), a resist diameter for manufacturing the orifice hole 12 is required, and the diameter is d3. Normally, the resist portion has a slightly concave shape at the time of manufacture. Regarding the size of each chamber, the shortest width of the pressurizing chamber 16 is L
2. The shortest width of the restrictor flow path 17 is L3. Normally, the shortest width L2 of the pressurizing chamber 16 is the same as or slightly smaller than the shortest width L3 of the restrictor flow path 17. Further, the amount of the adhesive protruding portion 32 protruding along the orifice plate 11 is set to L1.

FIG. 2 is a perspective view of the ink flow path for explaining the flow of the ink.

Reference numeral 51 denotes an ink manifold which forms a common ink passage, and reference numeral 18 denotes a filter formed on the front surface of the ink manifold and formed on the diaphragm plate 15 for filtering ink foreign matters. The nozzle is a filter 18
Are arranged vertically in contact with. The ink is branched from an ink tank (not shown) to a plurality of arranged ink manifolds 51. Ink manifold 51
Also, the nozzles are branched into individual nozzles through the filter 18. The ink that has passed through the filter is ejected from the restrictor channel 17 to the outside through the pressurizing chamber 16 and the orifice hole 12. Here, in order to stabilize the ink droplets at each nozzle, the voltage applied to the piezoelectric element 20 of each nozzle may be adjusted so that the ink droplet speed becomes the same. However, regarding the decrease in paper deposition accuracy due to the bending of ink droplets, it is the best measure to prevent defects from being produced during production.

The bending of the ink droplet when it is discharged from the orifice hole 12 is caused by the ink film in the orifice hole 12 or by the unevenness of the hole shape inside the orifice hole 12. Among these, the causes of unevenness in the orifice hole 12 include a defect in the orifice hole 12 such as a bump, and a defect due to the flow of the adhesive during the bonding operation.

In order to control the flow of the adhesive, the adhesive is diluted with an organic solvent (for example, acetone, methyl ethyl ketone, ethyl alcohol) or the like, and the thickness is spread from several microns to several tens of microns by spray coating. Then, it is necessary to perform preheating before bonding to suppress the flowability, and then to paste. When the orifice plate 11 and the chamber plate 13 are attached, the adhesive may be applied only to the chamber plate 13 side. Because, in order to apply the adhesive to the orifice plate 11, the mask must be masked so that the adhesive does not enter the orifice hole 12, and the amount of the adhesive applied to the orifice plate and the amount of the adhesive applied to the chamber plate are reduced. , It is necessary to take into account the variation of the amount applied,
Adhesive application work is complicated.

In this example, the diluted adhesive is spray-coated to make a single coating thickness of 2 to 5 μm, and the coating thickness is 4 to 8 μm.
It is applied repeatedly to a thickness of 10 to 40 μm. At the time of bonding, the temperature is about 20 ° C. lower than the curing temperature of the adhesive.
After pre-curing for about 0 minutes, the plates are stuck together, and after applying a load, they are fully cured. At this time, trial production was repeated with the amount of the adhesive protruding from the orifice plate side being 50 μm as a standard, and it was found that the amount of the adhesive protruding varied from 10 μm to 100 μm. It is conceivable that the amount of the adhesive is reduced and the load is increased, but the amount of expansion is increased when the plate is heated. When the thickness of the adhesive was simply reduced, air pockets 33 were generated in portions where the adhesive did not sufficiently flow as shown in FIG. 3 of the conventional example.

The above results are summarized as follows. That is, the shortest width L2 of the pressurizing chamber 16 of the chamber plate 13 is equal to the orifice hole 1 of the orifice plate 11.
The outer diameter d1 and the adhesive amount L1 may be larger than the sum of twice the protrusion amount L1, and can be expressed by the following equation.

[0021]

(Equation 3)

When the orifice plate 11 is manufactured by electroforming (electroforming), the orifice hole has a trumpet shape and it is difficult to define the opening of the hole. There is a depression on the exit side, and it has been confirmed that the hole diameter almost matches this. That is, d1 = d3. Therefore, the conditions at the time of electroforming are as follows.

[0023]

(Equation 4)

The orifice plate can be formed with a tapered hole by press working other than electroforming. As a processing method, a method is generally used in which a straight hole is formed, and then a predetermined amount is tapered by counterboring.

[0025]

As described above, according to the present invention, the amount of the adhesive protruding is regulated so that no air pocket is generated between the plates and the ejection of the ink droplets due to the protruding of the adhesive does not occur. As a result, a thin plate laminated inkjet head using an adhesive can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a nozzle of an inkjet head according to the present invention.

FIG. 2 is a perspective view of an ink flow path.

FIG. 3 is a sectional view of a nozzle according to a conventional technique.

FIG. 4 is a cross-sectional view of a nozzle according to a conventional technique.

[Explanation of symbols]

11 is an orifice plate, 12 is an orifice hole, 13
Is a chamber plate, 16 is a pressure chamber, 31 is an adhesive layer, 3
Reference numeral 2 denotes an adhesive protruding portion.

Claims (5)

[Claims] A chamber plate forming a pressurized chamber, a restrictor plate forming a pressurized chamber together with the chamber plate, and also forming a restrictor flow path for supplying ink to the pressurized chamber; A piezoelectric element that generates pressure fluctuations in the pressurized chamber by applying pressure, a diaphragm plate that forms at least a part of a wall surface of the pressurized chamber and is connected to the piezoelectric element with an elastic material, and supplies ink to the restrictor. An on-demand type multi-nozzle inkjet head having a plurality of nozzles constituted by a plate forming a common ink supply path and an orifice plate having an orifice hole for ejecting ink droplets from a pressurized chamber, at least an orifice plate And the chamber plate are bonded with an adhesive, and the following conditions are satisfied. On-demand type multi-nozzle inkjet head. Here, the diameter of the orifice hole of the orifice plate on the pressurizing chamber side is d1, the amount of adhesive protruding is L1, and the shortest width of the pressurizing chamber of the chamber plate is L2. (Equation 1) 2. The on-demand type multi-nozzle ink jet head according to claim 1, wherein the orifice plate is formed by electroforming, and the opening on the pressurizing chamber side is widened in a trumpet shape with respect to the outer opening of the orifice hole. A method for manufacturing an on-demand type multi-nozzle inkjet head, characterized by processing. 3. The on-demand type multi-nozzle ink jet head according to claim 1, wherein the orifice plate is formed by press working, and the opening on the pressurizing chamber side is widened in a tapered shape with respect to the outer opening of the orifice hole. A method for manufacturing an on-demand type multi-nozzle inkjet head, characterized by processing. 4. A method for manufacturing an on-demand type multi-nozzle ink jet head according to claim 2, wherein the amount of adhesive protruding between the orifice plate and the chamber plate is regulated to 10 μm to 100 μm. A method for manufacturing a demand type multi-nozzle inkjet head. 5. A method for manufacturing an on-demand type multi-nozzle ink jet head according to claim 4, wherein the adhesive material is diluted with an organic solvent to form a plate on each of the plates so that the amount of the adhesive protruding can be controlled. A method for producing an on-demand type multi-nozzle ink jet head, which comprises applying.