JPH0133344Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing screen used for screen printing.

BACKGROUND ART Screen printing has conventionally been used when coating a limited area to a certain thickness, such as when applying molybdenum paste to an alumina substrate.

This screen printing, as shown in Figure 1,
This is carried out in the following manner using a printing screen 3 made up of a screen 1 formed by forming a mesh of threads perpendicular to each other and held by a screen holding frame 2 formed in a rectangular shape by, for example, four frame plates. .

That is, a base paper 4 with character shapes to be printed, etc. cut out is held by the screen holding frame 2 so as to be in contact with the screen 1, and printing is performed so that this base paper 4 is in contact with the printing surface of the print target 5 made of an alumina substrate. At the same time, a rubber squeegee 6 coated with printing ink is placed in contact with the screen 1 and slid on the screen 1, so that the shape cut on the base paper 4 is aligned with the printing surface. It is mimeographed.

However, as I continued this screen printing,
The wires constituting the mesh of the screen 1 are extended, causing errors in the screen printed dimensions.

In particular, the printed pattern provided on the surface of the alumina substrate is often a circuit pattern for integrated circuits, and errors in printed dimensions result in product defects. In the case of screen printing of circuit patterns, in order to improve printing accuracy, the printing screen is placed slightly away from the alumina substrate surface, and printing is performed by linear contact between the printing screen and the alumina substrate using a squeegee 6. However, in this case, the printing screen is more likely to stretch, often resulting in errors in printing dimensions.

Therefore, with this type of printing screen, it is necessary to replace the screen with a new one every time it is used for a certain period of time.

The inventor of the present invention has conducted extensive research to extend the usable life of such conventional printing screens and has discovered the following facts.

That is, as shown in FIG. 2, the conventional printing screen is attached to the screen holding frame 2 so that both warp and warp threads constituting the mesh are inclined at 45 degrees with respect to the printing direction X. The usable life is the longest when the screen 1 is tilted from the position and one of the warp and warp yarns forming the mesh is tilted at 20 to 30 degrees with respect to the printing direction.

The present invention has been made based on this knowledge, and includes a printing screen in which a screen is held in a screen holding frame by a mesh made up of mutually orthogonal threads, and one of the orthogonal threads is printed on the screen. It is an object of the present invention to provide a printing screen characterized in that it is held by the holding frame so as to be inclined at 20 to 30 degrees with respect to the printing screen.

Hereinafter, details of the present invention will be described with reference to an embodiment shown in the drawings.

As shown in FIG. 3, the printing screen of the present invention has a screen 7 whose mesh is made up of weft and warp yarns (stainless steel wires) that are orthogonal to each other.
and a screen holding frame 8 formed in a rectangular shape with four frame plates that hold this screen 7, and one of the weft and warp yarns that are orthogonal to each other that make up the mesh of the screen 7 is printed. The screen 7 is held by a screen holding frame 8 so as to be inclined at α=20° to 30° with respect to the direction.

The threads forming the screen 7 are as follows:
Wires made of silk, synthetic fibers, etc., or stainless steel wires depending on the purpose, are used.

As shown in FIG. 4, the printing screen of the present invention constructed in this way has a smaller elongation of the mesh per unit number of prints than when α=0° or α=45°. It can be seen that the number of prints n until the screen reaches the dotted line indicating the life span of the screen shown by the dotted line in the figure is significantly extended.

Note that the screen holding frame is not limited to a rectangular shape.

As explained above, according to the present invention, the life of the printing screen can be significantly extended simply by changing the mounting direction of the screen, and is extremely economically effective.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the method of screen printing;
Figure 2 is an explanatory diagram showing a conventional printing screen;
FIG. 3 is an explanatory diagram showing the printing screen of the present invention, and FIG. 4 is a graph showing the relationship between the number of prints n and the elongation of the mesh, depending on the relationship between the threads constituting the mesh and the printing direction. 1, 7... Screen, 2, 8... Screen holding frame, 6... Squeegee.

Claims (1)

[Scope of utility model registration request] In a printing screen in which a screen is held by a screen holding frame, the screen is made up of a mesh made of mutually orthogonal threads, and the screen is held such that one of the orthogonal threads is inclined at an angle of 20 to 30 degrees with respect to the printing direction. A printing screen for applying paste to an alumina substrate, characterized in that it is held in a frame.