JP3749329B2 - Method for manufacturing nozzle plate for ink jet printer head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface treatment method for a nozzle plate used in an ink jet printer head.
[0002]
[Prior art]
Conventionally, in an inkjet printer, which is one type of non-impact printer in a computer output application field, Japanese Patent Publication No. 4-48622 and Japanese Patent Application Laid-Open No. 63-247051 have applied a piezoelectric action of a piezoelectric body to an ink ejection driving force. It is proposed in the gazette.
[0003]
In the manufacturing method and structure described in these publications, after processing a fine through groove for an ink flow path on a piezoelectric substrate, an electrode film is formed on the surface, the surface is polished, Leave the electrode film on.
[0004]
Further, a parylene film made of polyparaxylylene resin by a vapor phase synthesis method is formed as an insulating film on the inner surface of the groove. This insulating film is positioned as an important component for preventing the generation of bubbles due to the electrolysis of ink which causes unstable ink discharge and the deterioration of the ink.
[0005]
Bonding the grooves having the grooves of the piezoelectric substrate manufactured as described above, or by bonding a flat lid made of glass, ceramic, metal, or plastic on the grooved surface, Form.
[0006]
Further, an ink jet printer head is constructed by bonding a 0.1 mm thick nozzle plate having an ink discharge hole with a diameter of 30 to 60 microns to one end of the ink flow path and then connecting a drive circuit to the electrode. The At this time, a nozzle plate made of metal, plastic or ceramic is used as the material of the nozzle plate.
[0007]
The drive principle of an inkjet printer head using piezoelectric action is modified so that when a voltage is applied to the electrodes formed in each groove, the partition wall forming the groove increases or decreases the volume of the ink flow path due to the piezoelectric action. To do. Then, the pressure generated by the reduction deformation is propagated to the ink filled in the groove and ejected as ink droplets from the ink ejection holes.
[0008]
In general, in order to eject ink droplets stably, it is necessary to prevent adhesion of residual ink around the ink ejection holes after ejection in the nozzle plate, and to be chemically stable against water-based or non-water-based inks. It is requested.
[0009]
As a means for that, it has been proposed to form a liquid-repellent coating surface on the ink ejection surface. Silicone resin, fluororesin, or Teflon eutectoid plating can be used as a material that exhibits liquid repellency. Films and the like are known.
[0010]
[Problems to be solved by the invention]
However, when forming a liquid repellent film as described above, it is known that the position of the ink meniscus is determined by the position of the liquid repellent film entering the ink discharge hole, which greatly affects the ink discharge characteristics. It has been. Therefore, it is required to precisely control the amount of liquid repellent coating entering the ink ejection holes and to keep the meniscus position constant. In other words, if the amount of liquid repellent coating entering is close to the ink ejection surface, erroneous ejection is likely to occur due to mechanical vibration from the outside, and if the amount of penetration is far from the ink ejection surface, it is easy to entrain bubbles after ejecting ink droplets. The discharge characteristics become unstable. Furthermore, the meniscus position determined by the amount of the liquid-repellent coating penetration greatly depends on parameters such as ink flow path dimensions, nozzle plate thickness, ink ejection hole size, ink type, driving method, and driving force. Therefore, a forming technique capable of changing the position is required.
[0011]
As the method, for example, a photosensitive resin film is pressure-contacted with JP-A-7-125220 from the ink discharge back surface of the nozzle plate, a part of the film enters the ink discharge hole and is cured, and then Teflon eutectoid plating is performed. In this method, since the amount of the photosensitive resin film entering is adjusted by temperature, it is difficult to accurately control the boundary position, and in addition, the diameter of the ink discharge hole is increased to increase the printing resolution. Is reduced, it becomes difficult for the photosensitive resin film to enter the ink discharge holes, and it is difficult to accurately control the amount of the water-repellent coating entering the ink discharge holes.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to accurately control the amount of liquid repellent coating entering the ink ejection holes and to keep the meniscus position constant, a surface treatment method for a nozzle plate for an ink jet printer head. Is to provide.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the following means are employed in the surface treatment method for an ink jet printer head nozzle plate of the present invention.
[0014]
The surface treatment method for a nozzle plate for an ink jet printer head according to the present invention comprises a flat plate member having an ink discharge surface on one side, and an ink jet printer head having a penetrating ink discharge hole through which ink is discharged at a predetermined position of the flat plate member. A step of covering and curing a positive photosensitive resin from the ink discharge surface to the inside of the ink discharge surface and the inside of the ink discharge hole, and a step of covering and curing the back side of the ink discharge surface with a positive photosensitive resin; And a step of developing the positive photosensitive resin by exposing the ink discharge surface to ultraviolet rays, a step of coating the liquid repellent film, and a step of removing the positive photosensitive resin.
[0015]
The surface treatment method for a nozzle plate for an ink jet printer head according to the present invention is characterized in that the amount of the positive photosensitive resin entering the ink ejection holes is controlled by the exposure amount and the exposure time.
[0016]
In the surface treatment method for an ink jet printer head nozzle plate according to the present invention, the positive photosensitive resin has a viscosity of 100 centipoise or less.
[0017]
(Function)
In the nozzle plate surface treatment method of the present invention, first, the ink discharge surface and the inside of the ink discharge hole are covered and filled with a positive photosensitive resin, specifically, a liquid positive photosensitive resist, and cured. At this time, since the positive photosensitive resin needs to be filled in the ink ejection holes, a liquid resist having a low viscosity, specifically, 100 centipoise or less is used.
[0018]
A positive photosensitive resin is applied from the ink discharge surface with a spinner, and the ink discharge surface and the inside of the ink discharge hole are filled and coated and cured. Subsequently, a positive photosensitive resin is coated with a spinner on the back surface of the ink discharge and cured. Since the ink discharge surface is coated with positive photosensitive, contamination of the surface caused by touching the spinner base when the positive photosensitive resin is coated on the ink discharge back surface is prevented.
[0019]
Next, ultraviolet rays are exposed from the ink ejection surface. At this time, by controlling the exposure intensity and the exposure time, the amount of dissolution of the positive photosensitive resin by development can be controlled. That is, since the positive photosensitive resin serves as a masking material for the liquid-repellent coating to be formed, the amount of positive photosensitive resin entering the ink ejection holes is controlled by the exposure amount and the exposure time. It becomes possible to control the amount of wraparound of the coating.
[0020]
In order to form a liquid repellent coating, it is important to keep the ink ejection surface clean in advance. When cleaning is performed after masking, the positive photosensitive resin as a masking material is destroyed depending on the cleaning agent. For this reason, it is desirable to clean the ink discharge surface strongly before masking and keep the ink discharge surface clean without contamination until the liquid repellent coating is formed. According to the present invention, when the ink discharge back surface is coated with the positive photosensitive resin, the ink discharge surface does not touch the base of the spinner and can be kept clean without being contaminated. it can.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a surface treatment method for an ink jet printer head nozzle plate according to an embodiment of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is a schematic sectional view showing the structure of a nozzle plate for an ink jet printer head in an embodiment of the present invention. In the nozzle plate for the ink jet printer head, the ink discharge surface 30 is coated with a liquid repellent film 50, and a part of the liquid repellent film 50 enters the ink discharge hole interior 70. This structure stabilizes the meniscus position during ink ejection. 2 to 6 are process cross-sectional views showing a surface treatment method for an ink jet printer head nozzle plate in an embodiment of the present invention.
[0023]
First, as shown in FIG. 2, a positive type is formed on the ink ejection surface 30 of the nozzle plate 10 having a circular through hole for ink ejection having a length of 50 mm, a width of 15 mm, and a thickness of 0.1 mm, and the ink ejection hole inside 70. The photosensitive resin 40 is coated and filled and cured.
[0024]
The nozzle plate 10 is a nickel plate produced by an electroforming method, but may be another material, for example, a stainless steel plate in which the ink discharge holes 20 are formed by plastic working, or a nozzle plate made of a plastic material produced by an injection molding method.
[0025]
The diameter of the ink discharge hole 20 on the ink discharge surface 30 is 35 microns, and the diameter of the back surface is 100 microns. In order to supply ink smoothly and discharge it straight, its cross section is tapered, and this embodiment Thirty ink ejection holes 20 are opened in the nozzle plate used in the example.
[0026]
Since the positive photosensitive resin 40 needs to be filled up to the inside 70 of the ink ejection holes, a liquid resist having a low viscosity, specifically, 100 centipoise or less is used.
[0027]
In this embodiment, a positive photosensitive resist of OFPR-800 manufactured by Tokyo Ohka Co., Ltd. having a viscosity of 30 centipoise was used, and the resist was dropped from the ink ejection surface 30 in a state where the ink ejection back surface 60 was pressure-bonded to a silicon rubber sheet. Thereafter, coating and filling were performed by a spin coating method. It hardens | cures at the temperature of 60 to 100 degreeC in this state.
[0028]
Next, when pressure is applied to the silicon rubber sheet with the ink discharge back surface 60 facing up, and a positive photosensitive resist is dropped onto the ink discharge back surface 60 and coated by spin coating, the state shown in FIG. 3 is obtained. It hardens | cures at the temperature of 60 to 100 degreeC in this state.
[0029]
Next, ultraviolet light (wavelength 365 nm) is irradiated from the ink discharge surface 30. Thereafter, by immersing in an alkaline developer, the portion exposed by ultraviolet rays is dissolved, and the state shown in FIG. 4 is obtained.
[0030]
The exposure intensity of ultraviolet rays used in this example is 10 mW / cm ² , and the distance L from the ink ejection surface 30 to the photosensitive resin 40 is increased by increasing the exposure time to 5 seconds, 10 seconds, and 20 seconds, respectively. It was confirmed to be 5 μm, 8 μm, and 15 μm. In this embodiment, the exposure time is set to 5 seconds, and the distance L from the ink discharge surface 30 to the photosensitive resin 40 is set to 5 μm.
[0031]
Next, as shown in FIG. 5, Teflon eutectoid plating is performed to form a water-repellent coating 50 on the nozzle plate 10.
[0032]
This plating process can be performed by any plating method such as electroplating or electroless plating. In this example, electroless plating called trade name Kaniflon (Nihon Kanisen Co., Ltd.) was employed.
[0033]
The plating thickness of the Teflon eutectoid plating can be controlled by the immersion time in the plating solution, and is 3 μm in the examples of the present invention.
[0034]
It was confirmed by electron microscope observation that fluororesin fine particles having a diameter of 0.2 μm were uniformly dispersed in the Teflon eutectoid plating film in the range of 20 to 30 vol%.
[0035]
Next, the positive photosensitive resin 40 is dissolved and removed using a solvent. In this example, acetone was used.
[0036]
In this way, as shown in FIG. 1, the liquid repellent coating 50 enters the ink ejection hole interior 70, and the nozzle plate for an ink jet printer head having a constant entry position is completed.
[0037]
Further, in order to increase the hardness of the Teflon eutectoid plating surface and increase the wear resistance, it is preferable to heat-treat at 350 to 400 ° C. after dissolving and removing the positive photosensitive resin 40.
[0038]
In order to confirm the effect of the example of the present invention, a photosensitive resin film was pressed from the ink discharge back surface 60 of the nozzle plate 10 instead of the positive photosensitive resin 40 used in the example as the comparative sample 1, and the film A part of the ink was penetrated into the ink discharge hole 70 and cured, Teflon eutectoid plating was performed, the film was removed, a heat-treated nozzle plate was produced, and a cross-sectional SEM observation of the ink discharge hole internal 70 was performed. As a result, in the nozzle plate according to the present invention, the distance from the ink discharge surface 30 of the Teflon eutectoid plating that entered the inside 70 of the ink discharge holes was 5 μm in all the ink discharge holes 20. However, it was confirmed that the distance from the Teflon eutectoid plating ink discharge surface 30 that entered the ink discharge hole interior 70 irregularly varied in the range of 5 μm to 20 μm in the nozzle plate of Comparative Sample 1.
[0039]
In order to confirm the effect of the embodiment of the present invention, the positive photosensitive resin 40 is applied from the ink discharge back surface 60 without covering the ink discharge surface 30 as the comparative sample 2 on the ink discharge surface 30. The ink discharge back surface 60 and the ink discharge hole interior 70 were filled and covered and cured, and the other processes were the same as in the example. As a result of SEM observation of the surface of the Teflon eutectoid plated surface, generation of plating spots was observed.
[0040]
In addition, as a result of assembling the head using the nozzle plate according to the present invention and the nozzle plate of Comparative Sample 1 and injecting pigment-based ink and conducting a continuous discharge test, the head using the nozzle plate according to the present invention stably discharges. However, the head using the nozzle plate of the comparative sample has a phenomenon that the ink ejection direction is bent or the ink is not ejected at all.
[0041]
As can be seen from the above results, the nozzle plate for an ink jet printer head according to the present invention has a precise control of the position where the liquid repellent coating 50 enters the ink discharge hole 70, the meniscus position is constant, and stable ink discharge. Confirmed to be possible.
[0042]
【The invention's effect】
As is clear from the above embodiments, the nozzle plate for an inkjet printer head according to the present invention coats and fills the ink discharge surface and the inside of the ink discharge hole with a positive photosensitive resin from the ink discharge surface, and cures the ink discharge back surface positively. It is coated and cured with a mold-type photosensitive resin, exposed and developed from the ink ejection surface, coated with a liquid-repellent film, and then removed into the ink ejection holes of the liquid-repellent film by removing the positive-type photosensitive resin. The intrusion position is precisely controlled, and the meniscus position is constant. As a result, ink can be stably ejected, and the reliability of the ink jet printer can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a nozzle plate for an inkjet printer head and a surface treatment method in an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a surface treatment method for an ink jet printer head nozzle plate in an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a surface treatment method for an ink jet printer head nozzle plate in an embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a surface treatment method for an ink jet printer head nozzle plate in an embodiment of the present invention.
FIG. 5 is a cross-sectional view illustrating a surface treatment method for an ink jet printer head nozzle plate according to an embodiment of the present invention.
[Explanation of symbols]
10 Nozzle plate 20 Ink discharge hole 30 Ink discharge surface 40 Positive photosensitive resin 50 Liquid repellent coating 60 Ink discharge back surface 70 Inside of ink discharge hole

Claims (3)

A step of the positive photosensitive resin from the ink discharge surface of the plate-like member having a through-nozzle discharge hole ink is ejected filled coating inside the ink ejection surface and the ink discharge hole cured in place, the ink discharge surface a step of back side was coated with the positive photosensitive resin curing, a step of developing the enter and exposed to ultraviolet rays to a position positive photosensitive resin inside the ink discharge holes than ink ejection surface, the liquid repellent film ink ejection A method for manufacturing a nozzle plate for an ink jet printer head, comprising: a step of covering from the surface to a position where the ink discharge hole enters, and a step of removing the positive photosensitive resin. 2. The method for producing a nozzle plate for an ink jet printer head according to claim 1, wherein the amount of the positive photosensitive resin entering the ink ejection hole is controlled by exposure intensity and exposure time. The method for producing a nozzle plate for an ink jet printer head according to claim 1, wherein the viscosity of the positive photosensitive resin is 100 centipoises or less.

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