JPH0288284A - Screen printing method - Google Patents

Abstract

PURPOSE:To print all patterns with the same thickness by moving a squeegee slantly to a pattern to be printed. CONSTITUTION:When a pattern is formed on a screen 1, a pattern 3 is designed so that all the pattern is previously disposed in the diagonal direction. A squeegee 5 is moved in parallel to one edge of the screen 1. Therefore, the squeegee 5 moves at an angle of 45 degrees relatively to the direction of the pattern. Then, a part in parallel to the squeegee 5 is printed boldface and a part vertical thereto is printed lightface. However, these effects are cancelled with each other to make their thickness constant. In this manner, bleeding and blur in printing can be perfectly eliminated all over the pattern. Thus, a printing with a fine pattern is made available.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in a screen printing method used for pattern printing on printed circuit boards and the like.

<Prior Art> Methods for forming patterns on printed circuit boards include a photographic method in which a resist is applied to the board, a cyst is exposed and developed thereon, and a printing method in which a pattern is directly printed on the board. The printing method is suitable for mass production and is economical.

Screen printing is used to form the required pattern on a screen woven from polyester or stainless steel fibers.

The screen printing method is characterized by a thick ink layer and excellent ink coverage. The screen printing method will be explained with reference to FIG. In FIG. 3, a screen 1 made of polyester or stainless steel fibers is fixed to a frame 2. A pattern 3 is formed on this screen 1.

4 is cream solder which is ink, and screen 1
placed on one end of the Further, a printed circuit board (not shown) on which a pattern is printed is fixed on the opposite side of the screen 1 with a slight gap therebetween. The cream solder 4 is raked in the direction of the arrow with a spatula-shaped squeegee 5 made of rubber, and moved over the pattern 3. Therefore, the cream solder 4 passes through the pattern 3 portion of the screen 1 and is fixed to the printed circuit board. In this way, the pattern 3 on the screen 1 is printed on the printed circuit board.

<Problems to be Solved by the Invention> However, such screen printing methods have the following problems. FIG. 4 shows the printed circuit board after printing, where 6 is the printed circuit board and 7 is the pattern printed thereon. That is, in the conventional screen printing method, the part of the pattern parallel to the direction of movement of the squeegee 5 tends to be printed thickly, and the part perpendicular to it tends to be printed thinly.
In particular, when printing fine patterns, short circuits and blurring occur, causing printing defects.

<Object of the Invention> An object of the invention is to provide a screen printing method that can print all patterns with the same thickness.

Means for Solving the Problems> In order to solve the above problems, in the present invention, the squeegee is moved diagonally with respect to the pattern to be printed.

<Example> FIG. 1 shows the configuration of an apparatus used in the screen printing method according to the present invention. The same elements as in FIG. 3 are denoted by the same reference numerals, and their explanation will be omitted. (A) is a view seen from the top, and is basically the same as the conventional example in Figure 3, but when forming a pattern on screen 1, the direction of pattern 3 is all diagonal. Designed to be.

The squeegee 5 is moved parallel to one side of the screen 1. Therefore, the squeegee 5 is 45 mm in the direction of the pattern.
Move to an angle of °. As described above, the portions parallel to the squeegee 5 are printed thicker and the portions perpendicular to the squeegee 5 are printed thinner, but in this embodiment, these effects cancel each other out and the thickness remains constant. (B) is a side view, where 6 represents a printed circuit board and 8 represents support means for supporting this printed circuit board. Further, the support means 8 is capable of rotating the printed circuit board 6 around its axis. The pattern on the screen 1 is formed so that its direction is in the direction of the diagonal line of the screen 1, but the pattern printed on the printed circuit board 6 is not necessarily diagonal to that side. The printed circuit board 6 is rotated by a necessary angle to print a pattern at a predetermined angle. (C
) is an example of a printed pattern, screen 1
Even though the upper pattern 3 is parallel to its diagonal, it can be printed parallel to one side of the printed circuit board 6. By changing the rotation angle of the support means 8, a pattern can be printed in any direction.

FIG. 2 shows another embodiment. Note that the same elements as in FIG. 1 are given the same reference numerals and their explanations will be omitted. In this embodiment, the angle of the moving direction of the squeegee 5 is changed depending on the direction of the pattern 3.

That is, the squeegee 5 is set by a support device (not shown) so that its moving direction is at an angle of 45° with respect to the direction of the pattern 3. Therefore, for the same reason as in the embodiment of FIG. 1, the patterns printed on the printed circuit board have the same thickness. This embodiment has the advantage that the direction of the pattern formed on the screen 1 is not restricted and there is no need to rotate the printed circuit board.

Note that the direction of the pattern on the screen 1 is preferably at an angle of 45° with respect to the moving direction of the squeegee 5, but there is no restriction to this angle as long as it is oblique.

Further, the ink is not limited to cream solder, and resist, printing ink, etc. can be used.

<Effects of the Invention> As described above in detail based on the embodiments, in the present invention, the squeegee is moved diagonally with respect to the direction of the pattern on the screen.

Therefore, the thickness of the printed pattern does not change depending on the direction of the pattern on the screen, and the thickness of the printed pattern does not change depending on the direction of the pattern, so there is no bleeding or blurring of the print over the entire pattern. There is an effect that it can be done. Therefore, it becomes possible to print fine patterns.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the steps of the screen printing method according to the present invention, Fig. 2 is a block diagram showing another embodiment, Fig. 3 is a block diagram showing the conventional screen printing method, and Fig. 4 is a block diagram showing the steps of the screen printing method according to the present invention. This is a printed circuit board. ... Screen, 3... Pattern, 4... Cream solder, ... Squeegee, 6... Printed circuit board, 8... Support device. Figure (B) (C)

Claims (1)

[Scope of Claims] A screen printing method in which ink is placed on a screen and printed by scraping the ink with a squeegee, wherein the squeegee is moved diagonally with respect to the direction of the pattern on the screen. A screen printing method characterized by: