JPH0113097B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for improving the precision of solid metal masks used in screen printing. The present invention relates to the structure of a solid metal mask characterized by forming a dissimilar metal layer that cannot be corroded by any etchant and/or an extremely thin alloy layer that cannot be corroded by any etchant.

A solid metal mask is a type of plate printed using a screen printing method. In normal screen printing, an image is drawn on a screen using a photosensitive resin (hereinafter referred to as resist), and ink passes through mesh holes in the screen and adheres to the printing material. A screen in which this plate is entirely made of metal is generally referred to as a suspended metal mask screen. On the other hand, a plate that has no mesh holes at all, that is, the ink is pushed out straight through the mask in accordance with the image, is called a solid metal mask.

[Conventional technology]

The outline of the currently used plate-making method for solid metal masks is as follows.

1 Prepare a metal plate of the required thickness. (Today, stainless steel plates with a thickness of 100μ, 200μ, etc. are commonly used.) 2. Cut the metal plate to the desired size, degrease both sides, wash with water, dry, and then apply resist on both sides. and dry.

3 Place the film on both sides and expose.

4 Remove the film and wash with water.

5. Corrode the metal surface exposed by development using ferric chloride solution as an etchant, either simultaneously on both sides or one side at a time (if corroding one side at a time, attach a protective film to the other side).6. This is the Tsudo metal mask version.

The solid metal mask plate made through the above process is commonly used (for example, registered utility model No. 1343802)
Fix it to the screen frame using the method described below to make a printing board.

A cross-sectional view of this state is shown in FIG. In the figure, a indicates a frame, for example, an aluminum frame, b indicates stretchable gauze made of nylon, Tetron, etc., and a solid metal mask c is fixed to the center thereof with an adhesive d. Then apply the ink f to the printing material g using a squeegee e.
Extrude and print.

Since solid metal masks are used in printing methods that require a large amount of ink to be applied per unit area, the following characteristics are required.

1. Precision (sharpness) of the corrosion shape (shape of the corroded metal image) The sharpness of the corrosion shape is determined by the sharpness of the corrosion shape from the surface of the solid metal mask c that comes into contact with the printing material g from which the ink h is extruded, as shown in Figure 2. There is a particular requirement for c', and the outline must have acute angles (for example, if the outline is a rectangle, each corner must be acute), and the image must be faithfully reproduced on the film.

2. The amount of ink applied can be adjusted.

The amount of ink applied, that is, the amount of ink extruded, changes as the shape of the cross section changes due to corrosion. Third
As shown in figure a, the surface c″ of the solid metal mask c into which the ink is pushed and the surface from which the ink is pushed out.
If c' is the same, for example, when filling ink h into hole g' of printing material g, the amount of ink h is proportional to the thickness of solid metal mask c, but the third b
As shown in the figure, when the surface c'' into which the ink is pushed is larger than the surface c' through which the ink is pushed out, the amount h of the ink pushed out increases regardless of the thickness of the solid metal mask c.

A solid metal mask must be manufactured to have the above-mentioned through-hole cross-sectional characteristics depending on the intended use.

[Problem that the invention seeks to solve]

However, with the above-described process, a solid metal mask with satisfactory through-hole cross-sectional characteristics cannot be produced. This is because it has the following drawbacks.

1 Since it is a single metal (as stainless steel),
Even if a corrosion depth is set, considerable skill is required to stop corrosion at that depth.

(When corroding, the speed of corrosion differs significantly depending on whether the corrosive solution is new or used. Also, in the case of 50μ or 100μ corrosion, it is impossible to measure the depth during corrosion. (You will have to rely on intuition and reprinting will be completely impossible.) 2. When corrosion occurs on one side at a time, apply varnish to the corroded surface, but if the corroded area is small and the corrosion depth is deep, the varnish may not cover the corroded surface sufficiently. If it is not coated, corrosion will progress from one side, and when it penetrates, the corrosive liquid will corrode all the way to the metal surface that is not coated with varnish, making it unusable as a plate.

3. Since stainless steel is an alloy, when it corrodes, corrosion progresses in the vertical direction as well as the side wall direction (referred to as side etch), and as a result, the profile cannot be sharpened.

4 Since it is a single layer, only a uniform corrosion cross section can be produced.

5. When trying to penetrate holes of various sizes on the same plate, it is not possible to make the corrosion cross section the same because the corrosion speed differs depending on the size of the hole.

6. Even if you try to bridge the handle with metal that is 1/2 or 1/3 of its thickness, it is completely impossible.

The object of the present invention is to eliminate all of the above-mentioned drawbacks and provide an ideal solid metal mask.

Additionally, the present invention is based on the patent application filed in 1983 by the inventors.
-100556 (Japanese Patent Application No. 54-7679) was developed and improved for the plate making of solid metal masks.

[Means to solve the problem]

The present invention will be explained in more detail below.

The solid metal mask of the present invention basically consists of three layers as shown in FIG. Let's assume that the side where the ink enters is m (hereinafter referred to as the m layer),
If the side where the ink comes out is o (hereinafter referred to as the o layer),
A metal layer that can hardly be corroded by a corrosive solution that corrodes the m and o layers, that is, a dissimilar metal layer, is n
(hereinafter referred to as the n-layer).

When the cross-sectional form shown in FIG. 5c is required, the m layer and o layer may be made of nickel, and the n layer may be made of copper or brass. Then, nickel may be made into copper-nickel by a plating method, or nickel may be attached to both sides of a copper plate or a brass plate by a plating method. Next, as shown in FIG. 5a, the resist P, which has substantially symmetrical images aligned with each other on the front and back sides, is left only in optically desired areas and then etched. Forming images symmetrically on the front and back can be easily done using photographic technology. It is also easy to make one image slightly larger by using blurring or other methods. The corrosive liquid corrodes nickel with an acidic corrosive liquid which is a mixture of hydrogen peroxide and nitric acid as shown in Japanese Patent Publication No. 18944/1983 (Japanese Patent Application No. 48419/1982) filed by the inventors. This corrosive liquid can hardly corrode copper. When it is confirmed that the copper surface appears during corrosion and the corrosion is stopped, the result is as shown in Figure 5b. Next, the copper is corroded with an alkaline corrosive solution. This corrosive liquid cannot corrode nickel at all. Next, when the resist is peeled off, a shape as shown in FIG. 5c is obtained. FIG. 6 shows a cross-sectional view of the n-layer made of a metal that cannot be corroded by either acidic or alkaline corrosive liquids, such as a nickel-phosphorous alloy. The thickness of the n-layer in this case should be 0.5-2μ. When corroding from both sides with such a thin layer in between, this film must not be torn by the pressure applied during corrosion, so a hardness of 400 to 700 (Vickers hardness) is required. Furthermore, since this film must ultimately be removed and penetrated by a method other than corrosion, such as water pressure using a spray gun, it is required to be hard and brittle. In Figure 6a, the n layer is made of nickel, the m and o layers are made of nickel, and the nickel is corroded with a similar corrosive liquid to form the structure shown in figure 6b, and then penetrated with water pressure using a spray gun as shown in figure 6c. Remove part of the n layer.

Next, FIG. 7 shows a method for increasing printing accuracy. This type is necessary when attempting to perform thick film printing with high precision by creating a so-called V shape and increasing the precision of the contact surface with the printing medium.

The o layer is further divided into two as shown in Figure 7a.
The o′ layer and o″ layer are almost symmetrical, with the front and back sides aligned with each other as before, but the resist is left only in optically desired areas so that one image is slightly larger than the other. o Nickel was used as the contact layer with the printing material for the 'layer, copper for the o'' layer, nickel for the n layer, and nickel for the m layer.After corroding the nickel to form the layer shown in Figure 7b, It can be manufactured by making it as shown in Fig. 7c and finally removing the n layer using a spray gun to make it as shown in Fig. 7d. As a result, if the thickness of the o′ layer is set to 20 μm, for example, the side etch can be kept to 20 μm based on the relationship between the depth and the side etch described above, and the accuracy will be dramatically improved. Furthermore, if the o' layer is made even thinner, the accuracy will increase proportionally.

Although the cross-sectional shapes of the above-mentioned combinations are only a few examples, the cross-sectional shapes change in various ways depending on the combination, and we expect that the range of applications will further increase in terms of usage. For example, by manufacturing an optical slit plate (encoder), which is currently made of stainless steel, with the structure of the method of the present invention, a slit plate with higher precision can be obtained.

A more detailed explanation will be given below with reference to Examples.

Example 1 The surface of a stainless steel plate measuring 300 mm x 300 mm and 2 mm thick was made into a mirror surface, degreased with a 5% caustic soda aqueous solution, and then washed with water. Furthermore, in order to neutralize the remaining caustic soda, a 5% aqueous sulfuric acid solution was applied, followed by washing with water.
Next, while the surface was wet, it was nickel plated to a thickness of 50 μm using a normal sulfamic acid nickel plating bath. Immediately after finishing the plating, wash with water,
Next, use a normal nickel-phosphorus alloy plating bath to
It was plated to a thickness of 0.8μ, washed with water after plating, and plated again to a thickness of 50μ using a normal nickel sulfamic acid plating bath. After completing the above series of plating steps, the plating metal was peeled off from the stainless steel plate to obtain a solid metal mask plate. Next, a photosensitive resin (manufactured by KPR Kodak) was applied using a wheeler and dried using an infrared heater. Next, two films prepared in advance were placed in a vacuum printing frame and brought into close contact with each other, and exposed to ultraviolet light using a xenon lamp. After exposure, the film was peeled off, developed with a prescribed developer, and washed with water. Next, add 10% nitric acid and hydrogen peroxide to a regular paddle etching machine.
20% was added and corrosion was carried out at a liquid temperature of 28°C. After the corrosion on both sides was completed, the exposed nickel-phosphorus layer was removed using a spray gun. Finally, the resist was removed with a remover and washed with water to obtain a solid metal mask plate. As a result, we were able to create an ideal plate without the effects of corrosion from one side affecting the other. Another example of application is its use in vapor deposition masks.

Example 2 A brass plate with a size of 300 mm x 300 mm and a thickness of 100 μ was fixed to a wooden frame, and the surface was treated in the same manner as in Example 1. After that, a nickel plating with a thickness of 30 μ was applied on both sides in the same plating bath. I went. Next, the film was baked in the same manner as in Example 1, and then the nickel layer was etched using the same etching solution. As a result, corrosion stopped with the copper surface becoming slightly rough. Next, the brass was corroded inside the pad using an alkaline caustic solution containing aqueous ammonia. As a result, the brass surface was completely removed by corrosion, but no change was observed on the nickel surface. An example of this application is an optical slit plate.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing a state in which a solid metal mask plate is fixed to a screen frame to form a printing plate. FIG. 2 is a cross-sectional view schematically showing that the contour of the surface c' from which the ink h is extruded from the image hole of the solid metal mask c is required to have an acute angle. Figure 3a is a cross-sectional view schematically showing the situation when the hole diameter of the surface into which ink is pushed is the same as that of the surface from which the ink is pushed out, and Figure 3b is a cross-sectional view schematically showing the situation when the hole diameter of the surface to be pushed is wider than that of the surface from which the ink is pushed out. be. FIG. 4 is a sectional view showing three layers m, n, and o of a solid metal mask. Fig. 5a shows a situation in which a resist P is optically applied to the plate in Fig. 4 to prevent corrosion, Fig. 5b shows a situation in which areas other than the intermediate layer are corroded, and Fig. 5c shows a situation in which the intermediate layer is corroded with a different etchant. Both are schematic cross-sectional views showing the situation where the resist has been corroded and the resist has been removed. Figures 6a, 6b and 6c are examples similar to those in Figures 5a, 5b and 5c, except that the intermediate layer surrounds the metal which is not attacked by any corrosive liquid, e.g. FIG. In Figure 7a, the o layer is divided into two, and the contact layer with the printing material is made of nickel.
This is a cross-sectional view showing a situation in which a resist is applied to a copper layer o', a copper o'' layer above it, a nickel-phosphorus layer that is not corroded by any corrosive liquid, and a nickel layer m above it. Figure 7b shows the situation where nickel is corroded, and Figure 7c shows the situation where copper is further corroded.
The last figure is a cross-sectional view schematically showing the state in which nickel-phosphorus was removed using a spray gun. a: frame, b: stretchable nylon, tetron, etc. gauze, c: solid metal mask, d: adhesive,
e: squeegee, f: ink, g: printing material, c':
The surface of the solid metal mask where the ink is pushed out, c'': The surface where the ink is pushed, g': The hole in the printing material, m: The layer of the solid metal on the side where the ink enters.
o: layer on the side from which ink comes out, n: metal layer different from both m and o, l: three layers of m, n and o.

Claims (1)

[Claims] 1. On the front and back surfaces of a metal plate consisting of at least three layers integrally formed by plating with an intermediate layer made of a metal that can hardly be corroded by a corrosive liquid that corrodes metals in other layers. The through-image holes are formed by etching with different etchants, forming roughly symmetrical image resist removal portions aligned with each other, or by a combination of etchant attack and removal of the thin intermediate layer by physical force. Solid metal mask version. 2. The solid metal mask plate according to claim 1, wherein the intermediate layer is an alkali-soluble metal having a thickness of 10μ to 500μ. 3 The above intermediate layer can hardly be removed by corrosion.
Claim 1: The alloy has a thickness of 0.5 to 2μ.
Solid metal mask version described in section. 4 Claim 1 having an alkali-soluble metal with a thickness of 10μ to 500μ or an alloy that can hardly be removed by corrosion with a thickness of 0.5 to 2μ as the intermediate layer
Solid metal mask version described in section.