JPH09109400A - Manufacture of jet nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clear boundary between a hydrophilic part and a hydrophobic part and giving sufficient wear resistance in using a fluororesin to obtain a hydrophilic coat. SOLUTION: A resist coat 12 is formed on the surface of a nozzle plate 11 having a jet nozzle 11A, a part of which is inserted into the jet nozzle 11A, the resist coat 12 is exposed to light from the rear side of the nozzle plate 11 through the jet nozzle 11A and developed and removed except for at least a part remaining inside the jet nozzle 11A, and after the second plating 15 which is hydrophobic is formed outside the jet nozzle 11A by treating the nozzle plate 11 by electroless plating, using an electroless nickel plating liquid, the resist coat 12 is removed completely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method suitable for application in manufacturing jet nozzles in, for example, an ink jet printer.

In general, a nozzle for ejecting a liquid has many uses, and various structures are required depending on the use.

For example, an ink jet printing machine is a printing method in which ink is ejected at a high speed for printing, the dye medium is not wasted, the economy is high, and the environmental pollution is small. Has been done.

Generally, the print quality is subject to strict conditions for the hue and lightness of the dye, but in ink jet printing, strict conditions are also required for the uniformity of diameter of ink particles and the geometrical positional accuracy. Is imposed.

In order to satisfy the conditions peculiar to the ink jet printing, there is a large dependence on the ink jet nozzles, and it is necessary to improve it in various aspects. Means are provided.

[0006]

2. Description of the Related Art FIG. 5 is a fragmentary perspective view showing an ink jet head used in an ink jet printing machine.

In the figure, 1 is a nozzle plate, 1A is an ink jet nozzle, 2 is a plating film, 3 is a back plate, 4 is a piezoelectric element,
Reference numeral 5 is an ink supply pipe, and 6 is a pressure chamber.
The pressure chamber 6 in the figure is not yet filled with ink.

In the ink jet head shown in the figure, the displacement of the piezoelectric element 4 is utilized to suck ink from the ink supply tube 5 into the pressure chamber 6 or eject ink from the ink ejection nozzle 1A. There is.

In the ink jet printing machine, a distance is provided between the ink jet nozzle 1A and the paper to prevent the non-dried ink from being rubbed and causing the printing to be disturbed.

Therefore, a slight error in the ejection direction or an error in the ejection speed at the ejection nozzle 1A deviates the ink arrival position on the paper surface and impairs print quality.

One of the causes of the error in the ink jetting direction is the angular error of the shaft in the jetting nozzle 1A. According to the current machining technology, it is necessary to achieve a satisfactory accuracy. You can

However, at the tip of the ejection nozzle 1A on the front surface side, a pullback force due to the surface tension of the ink acts,
Then, the fluctuation of the pullback force becomes a problem.

FIG. 6 is a fragmentary perspective view showing an ink jet head for explaining the surface tension of the ink in the vicinity of the ejection nozzle. The same symbols as those used in FIG. Or have the same meaning.

In the figure, 7 indicates the ink filled in the pressure chamber 6, R indicates the curvature of the concave surface formed by the ink 7 being drawn, and θ indicates the wetting angle of the ink.

In the ink jet head, the ink 7
It is necessary to immediately suck the next ink 7 to be ejected from the supply tank immediately after the ejection of, and the negative pressure generated at that time is
It is carried by the surface tension of the ink 7 present in the ejection nozzle 1A.

As described with reference to FIG. 6, when the curvature of the concave surface of the ink 7 is R, the wetting angle of the ink 7 is θ, and the surface tension of the ink 7 is γ, the negative pressure P is P≈2γ cos θ / Represented by R.

Here, the wetting angle θ is zero if the surface of the ejection nozzle 1A that is in contact with the ink 7 is hydrophilic with good wettability, and at that time, from the above equation, the negative pressure P Is the maximum.

From the above, it is desirable that the inner surface of the ejection nozzle 1A be hydrophilic, and if so, the pullback force due to the surface tension of the ink 7 fluctuates, and in the ejection direction of the ink 7. Phenomena such as disturbance are reduced.

The cause of the disturbance of the ejection direction of the ink 7 in the ink jet head is not only the fluctuation of the pullback force due to the surface tension of the ink 7 in the ejection nozzle 1A.

FIG. 7 is a cutaway side view of an essential part of an ink jet head for explaining the disturbance in the ink jetting direction. The same symbols as those used in FIGS. 5 and 6 are the same parts. Represent or have the same meaning.

In the figure, 7A is an ink particle to be ejected, 8 is a paper powder fiber, P ₁ is a normal ejection direction, P
₂ shows the disturbed injection directions, respectively.

On the surface of the jet nozzle 1A, there are many occasions where fine dusts of paper to be printed adhere to the surface of the jet nozzle 1A. The problem is that the liquid surface on which the surface tension acts is enlarged, and the jetting direction of the ink 7 is inclined due to the force in the side direction thereof as shown by the arrow P ₂ .

As a means for preventing this, it is known that it is effective to make the surface of the nozzle plate 1 hydrophobic so that the ink 7 cannot exist on the side of the jet nozzle 1A.

As is clear from the above, it is desirable that the inner surface of the injection nozzle 1A be hydrophilic, and that the surface be hydrophobic, and the boundary between hydrophilic and hydrophobic is possible. It should be as narrow and clear as possible.

Conventionally, in order to achieve the above-mentioned object, it has been practiced to coat the surface of the nozzle plate 1 which is hydrophilic with a fluororesin, which is a representative of which exhibits hydrophobicity.

[0026]

In order to obtain hydrophobicity, a part of the conventional fluororesin coating applied enters the inner surface of the injection nozzle or sticks out of the necessary area. Have difficulty.

In addition, in the ink jet printer, an automatic cleaning mechanism is usually provided in order to wipe away paper dust and ink residues adhering to the surface of the jet nozzle, and the fluororesin is easy to wipe off at the time of wiping. It has the drawback of being worn out. Incidentally, the fluorine-based resin has a small friction coefficient, but is easily worn.

According to the present invention, a fluororesin is used to obtain a hydrophobic coating. However, a distinct boundary between the hydrophilic portion and the hydrophobic portion can be obtained, and the abrasion resistance is improved. Try to be enough.

[0029]

[Means for Solving the Problems] As a technique for improving the wear resistance of a hydrophobic coating made of a fluororesin, a hydrophobic surface is formed using an electroless nickel plating solution in which fine particles of the fluororesin are suspended. The technology is known.

When this technique is applied, it is possible to make the surface of the nickel-plated film, which is originally hydrophilic, to have a low wettability due to the fine particles of the fluororesin, which is hydrophobic. It is known that when the degree of roughness is rough, it becomes more difficult for a substance that is difficult to wet, and the wetting angle θ becomes significantly large due to the synergistic effect with the fine irregularities of the fluororesin.

By the way, even when the electroless nickel plating solution in which the fine particles of the fluorine-based resin are suspended is used for the plating, the plating film resulting from the plating is stopped only on the surface of the nozzle plate, and is applied to the inside of the injection nozzle. It is necessary to prevent the plating film from being formed.

In the method for producing an injection nozzle according to the present invention, (1) a photosensitive resist film (for example, a nozzle plate 11 made of stainless steel) having a nozzle plate (for example, a nozzle plate 11 made of stainless steel) having an injection nozzle (for example, the injection nozzle 11A) is formed. Forming a resist film 12) so that a part of the resist film is inserted into the spray nozzle, and exposing the photosensitive resist film from the back surface of the nozzle plate through the spray nozzle to develop the resist film, and at least partially developing the photosensitive resist film. Is a step of removing the photosensitive resist film remaining in the injection nozzle and removing the others, and an electroless plating solution exhibiting hydrophobicity (for example, an electroless nickel plating solution in which fine particles of a fluororesin are suspended). Electroless plating is performed on the surface of the nozzle plate using the above to form a hydrophobic plating film (for example, a hydrophobic second plating film 15) other than in the injection nozzle, and then the photosensitive resist. And a step of completely removing the coating film, or

(2) In the above (1), when light travels through the photosensitive resist film defined by the jet nozzle, the light is bent toward the center of the jet nozzle, and the exposed portion, that is, the developed portion. The remaining portion is a frustoconical shape that is slightly inclined toward the surface, or

(3) In the above (1) or (2), the nozzle plate is made of a material having conductivity and hydrophilicity (for example, stainless steel), or,

(4) In the above (1) or (2), the nozzle plate is characterized in that a hydrophobic material (for example, resin) is previously subjected to hydrophilic treatment, or

(5) In the above (1) or (2), the surface of the nozzle plate is electroless plated using a hydrophilic electroless plating solution to obtain a hydrophilic plating film (eg, hydrophilic A certain first plating film 14) is formed, and then electroless plating is performed using a non-electrolytic plating liquid exhibiting a hydrophobic property, so that a hydrophobic plating film (for example, a hydrophobic second plating film) is provided outside the injection nozzle. Plating film 1
5) is included, or

(6) In any one of the above (1) to (5), the electroless plating solution exhibiting hydrophobicity contains fine particles of a substance exhibiting hydrophobicity (for example, fine particles of fluororesin). It is characterized by

In a liquid jet member such as an ink jet head using the nozzle plate processed as described above, good hydrophilicity is maintained in the jet nozzle, and the wetting angle θ is zero or close to it. , The negative pressure P can be set to a maximum value or a value close to the maximum value, and since the outside of the ejection nozzle is sufficiently hydrophobic, there is no fear that liquid such as ink spreads laterally. As a result, a certain amount of liquid such as ink can be ejected with good directionality.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 are side sectional views showing a main part of a nozzle plate in a process step for explaining one embodiment of the present invention. Will be described with reference to FIG.

Referring to FIG. 1A 1- (1) The ink jet nozzle 11A is formed in the nozzle plate 11 by applying an appropriate technique. There are many techniques applied in this case, such as a mechanical perforation technique and an etching technique.

See FIG. 1B. 1- (2) By applying a resist process in the lithography technique, the resist film 1 is formed on the surface side of the nozzle plate 11.
Form 2 In this case, a part of the resist film 12 is in a state of slightly entering the injection nozzle 11A.

2 (A). 2- (1) When light is irradiated from the back side of the nozzle plate 11, the nozzle plate 1
Since 1 plays the role of a mask, only the portion of the resist film 12 exposed in the jet nozzle 11A is exposed to light, and the photoreaction proceeds from the inside to the outside of the jet nozzle 11A.

In this case, the area of the exposure is reduced from the inside to the outside of the jet nozzle 11A, and when viewed from the side, it is tapered like a truncated cone.

2 (B) 2- (2) The resist film 12 is developed to remove the unexposed portion. 2- (3) A protective film 13 is formed to prevent the back surface of the nozzle plate 11 from being plated.

Referring to FIG. 3 (A) 3- (1) The first electroless plating film 14 which is hydrophilic is formed by applying the electroless plating method using a hydrophilic material plating solution. , Is formed only on the nozzle plate 11, and is not deposited on the resist film 12.

3- (2) By applying the electroless plating method using a hydrophilic material plating solution in which fine particles of a fluororesin are suspended, the second plating film 15 which is hydrophobic is formed. Form. Also in this case, only the first plating film 14 is formed, and the resist film 12 is not deposited.

See FIG. 3B. 3- (3) When the resist film 12 is removed by immersing it in a resist stripping solution, a hydrophilic first plating film 14 and a hydrophobic film are formed in the vicinity of the outlet of the injection nozzle 11A. It is possible to obtain a structure in which the transparent second plating film 15 is laminated while maintaining a clear boundary.
The protective film 13 is also removed in this step.

3- (4) Thereafter, the ink jet head is assembled using the nozzle plate 11 processed as described above.

FIG. 4 is a side sectional view showing a nozzle plate and the like in a process step for explaining another embodiment of the present invention, which is used in FIGS. 1 to 3. The same symbols as those used to represent the same parts or have the same meanings.

In the figure, 16 is a dry film resist, 17 is a flexible body, and 18 is a pressure rigid body.

In this case, the dry film resist 16 is placed on the nozzle plate 11 having the injection nozzle 11A, and the flexible body 17 is pressed by the pressing rigid body 18 facing the dry film resist 16. , Injection nozzle 11A
A part of the dry film resist 16 is pushed into the inside.

Therefore, thereafter, the ink jet head can be completed through the same steps as those described with reference to FIGS.

In the above embodiment, when a hydrophilic material is used as the material of the nozzle plate 11, the formation of the hydrophilic first plating film 14 can be omitted, and the hydrophilicity can be omitted. In order to form the first plating film 14 that has the property of being hydrophobic, the material of the nozzle plate 11 is hydrophobic, for example, the injection nozzle 11A is formed by pressing, or
A resin that can be formed by molding can be selected.

As described above, when resin is used for the nozzle plate 11, immediately after forming the injection nozzle 11A,
Area including the inside of the injection nozzle 11A, or the injection nozzle 1
It is also possible to form a hydrophilic coating on the entire surface including the inside of 1A.

As described with reference to FIG. 4, when a part of the dry film resist 16 is inserted into the jet nozzle 11A of the nozzle plate 11, a small amount of solvent is added to swell the dry film resist 16. It is also possible to make them bite.

[0056]

【Example】

Example 1 (1) A dry film resist (ORD) was formed on the surface of a nozzle plate 11 made of stainless steel having a diameter of 35 [μm] and an injection nozzle 11A of 80 [μm].
YL PR115: made by Tokyo Ohka) 16 at temperature 120
Laminate at [° C].

(2) From the back surface of the nozzle plate 11, ultraviolet rays having main wavelengths of 432 [nm] and 365 [nm] are applied for 15 minutes.
0 [mJ / cm ² ] as a dry film
The resist 16 is selectively exposed.

(3) When the dry film resist 16 was developed using a dedicated developer, the frustoconical dry film resist 16 remained with the jet nozzle 11A blocked.

(4) On the back surface of the nozzle plate 11, PET (p
ollyethylene terephthalate
e) The protective film 13 made of a film is attached at a temperature of 120 [° C.].

(5) A hydrophobic plating film 15 having a thickness of 10 [μm] to 40 [μ] is formed on the surface of the nozzle plate 11 by using an electroless nickel plating solution in which fine particles of fluororesin are suspended.
m] is selected and formed. Needless to say, the plating film is not formed on the dry film resist 16.

(6) The protective film 13 made of PET was peeled off, and the dry film resist 16 was removed using a peeling solution.

According to the first embodiment, the hydrophobic plating film 15 could be formed on the surface of the nozzle plate 11 except inside the injection nozzle 11A.

Example 2 (1) A jet nozzle 11A having a diameter of 35 [μm] is formed, and a protective film 13 made of PET film is formed on the back surface of a nozzle plate 11 made of stainless steel having a thickness of 80 [μm] at a temperature of 120. Attach at [° C].

(2) After applying a rubber photoresist (OMR83: made by Tokyo Ohka) on the surface of the nozzle plate 11, pre-baking is performed for 25 [minutes] in an oven at a temperature of 85 [° C.]. Thus, the resist film 12 is formed.

A part of the resist film 12 is the jet nozzle 1
Protective film 13 made of PET film that penetrates into 1A
Reach

(3) From the rear surface of the nozzle plate 11 to the protective film 1
Main wavelengths are 432 [nm] and 365 [nm]
Of ultraviolet rays of 400 [mJ / cm ² ],
The resist film 12 is selectively exposed to light.

(4) The resist film 12 was developed using an OMR developing solution (manufactured by Tokyo Ohka) and rinsed with an OMR rinse solution (manufactured by Tokyo Ohka), and the frustoconical shape was obtained with the injection nozzle 11A blocked. Resist 12 remained.

(5) The resist film 12 was dried by performing a heat treatment for 25 [minutes] in an oven at 145 [° C.].

(6) A hydrophobic plating film 15 having a thickness of 10 [μm] to 40 [μ] is formed on the surface of the nozzle plate 11 using an electroless nickel plating solution in which fine particles of a fluorine-based resin are suspended.
m] is selected and formed. Of course, the plating film is not formed on the resist film 12.

(7) The protective film 13 made of PET was peeled off, and the resist film 12 was removed using a peeling solution.

According to the second embodiment, the hydrophobic plating film 15 could be formed on the surface of the nozzle plate 11 except inside the spray nozzle 11A.

In the above embodiment, the ink jet
Although the case of forming the jet nozzle in the head has been described, the present invention is not limited to this, and can be widely applied to a field requiring a jet nozzle that needs to jet a predetermined amount of liquid in a directional manner. You can

[0073]

In the method of manufacturing an injection nozzle according to the present invention, a photosensitive resist film is formed on the surface of a nozzle plate having an injection nozzle, and a part of the photosensitive resist film is inserted into the injection nozzle to form a back surface of the nozzle plate. The photosensitive resist film is exposed through the spray nozzle and then developed to remove the photosensitive resist film, at least a part of which is present in the spray nozzle, and the others are removed to form a hydrophobic electroless plating solution. Electroless plating is performed on the surface of the nozzle plate using the above to form a hydrophobic plating film except in the injection nozzle, and then the photosensitive resist film is completely removed.

In a liquid ejecting member such as an ink jet head using the nozzle plate processed as described above, good hydrophilicity is maintained in the ejecting nozzle, and the wetting angle θ is zero or close to it, The negative pressure P can be set to a maximum value or a value close to the maximum value, and since the outer side of the ejection nozzle is sufficiently hydrophobic, there is no possibility that the liquid such as ink spreads laterally. As a result, liquid such as ink can be ejected with good directionality.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a main part of a nozzle plate at a process step for explaining an embodiment of the present invention.

FIG. 2 is a side sectional view showing a main part of a nozzle plate at a process step for explaining an embodiment of the present invention.

FIG. 3 is a cutaway side view of a main part showing a nozzle plate in a process key point for explaining an embodiment of the present invention.

FIG. 4 is a side sectional view showing a main part of a nozzle plate and the like in process steps for explaining another embodiment of the present invention.

FIG. 5 is a fragmentary perspective view showing an ink jet head used in an ink jet printing machine.

FIG. 6 is a fragmentary perspective view showing an ink jet head for explaining the surface tension of ink in the vicinity of an ejection nozzle.

FIG. 7 is a cutaway side view of a main part of an ink jet head for explaining the disturbance in the ink ejection direction.

[Explanation of symbols]

 11 Nozzle Plate 11A Ink Jet Nozzle 12 Resist Film 13 Protective Film 14 First Hydrophilic Plating Film 15 Second Hydrophobic Plating Film 16 Dry Film Resist 17 Flexible Body 18 Pressurized Rigid Body

Claims (6)

[Claims] 1. A step of forming a photosensitive resist film on a surface of a nozzle plate having an injection nozzle to allow a part of the photosensitive resist film to enter the inside of the injection nozzle, and the photosensitive material from the back surface of the nozzle plate through the injection nozzle. Exposing the resist film and then developing it to remove the photosensitive resist film, at least a part of which is present in the injection nozzle, and remove the others; and the nozzle using an electroless plating solution exhibiting hydrophobicity. A step of performing electroless plating on the surface of the plate to form a hydrophobic plating film other than in the injection nozzle, and then completely removing the photosensitive resist film. Manufacturing method. 2. When the light travels through a photosensitive resist film defined by the spray nozzle, the light is bent toward the center of the spray nozzle, and the exposed portion, that is, the portion left undeveloped, is slightly moved toward the surface. The method for manufacturing an injection nozzle according to claim 1, wherein the injection nozzle has a truncated cone shape inclined to the front. 3. The method for manufacturing an injection nozzle according to claim 1, wherein the nozzle plate is made of a material having a conductive and hydrophilic surface. 4. The nozzle plate is made of a hydrophobic material which has been previously subjected to hydrophilic treatment.
A method for manufacturing the jet nozzle described. 5. A hydrophilic plating film is formed by performing electroless plating on the surface of a nozzle plate using an electroless plating solution that exhibits hydrophilicity, and then using an electroless plating solution that exhibits hydrophobicity. The method for producing an injection nozzle according to claim 1 or 2, further comprising a step of performing electrolytic plating to form a hydrophobic plating film in addition to the inside of the injection nozzle. 6. The method for manufacturing an injection nozzle according to claim 1, wherein the electroless plating solution exhibiting hydrophobicity contains fine particles of a substance exhibiting hydrophobicity.