JPH0752359A - Squeegee for screen printer - Google Patents

Abstract

PURPOSE:To obtain a squeegee for a screen printer which has corner parts of a necessary curvature correctly and enables execution of excellent printing. CONSTITUTION:A squeegee for a screen printer which is used for spreading ink in the screen printer. The main body 1 of the squeegee is formed by molding, and curved-surface corner parts 1a, 1b, 1c and 1d having a circular-arc- shaped section and provided along the linear edge parts of the main body 1 of the squeegee are formed by a mold for molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeegee which is pressed against a plate of a screen printing machine and is used to spread ink on the plate.

[0002]

2. Description of the Related Art In a screen printing machine, printing is performed while spreading ink thinly on a stretched plate. To spread the ink thinly, a rubber plate-shaped squeegee moves over a plate. The squeegee is pressed against the plate and moved to perform printing while spreading the ink thinly on the plate.

[0003]

A squeegee of such a screen printing machine is attached to a movable body through a holder in an inclined state so that the corners of the straight edges of the lower part of the squeegee are pressed against the plate. Printing is carried out, but the corner of the linear edge to be pressed depends on the viscosity of the ink used or the thickness of the printing film to be printed, and the radius of the arc cross section of the curved corner. That is, it is necessary to change the curvature of the corners of the curved surface.

For this reason, conventionally, a squeegee of a screen printing machine is formed by molding so that all corners of a straight edge of a squeegee body are acute angles (right angles) at the time of manufacturing, and the squeegee is used in the printing machine. At this time, depending on the viscosity of the ink or the thickness of the printed film, the corner of the lower straight edge of the squeegee body is ground with a grinder to form the corner of the squeegee so that the desired curvature is obtained. Was there.

However, when the curved corners of the squeegee are formed by polishing, it is very difficult to form the corners with the required curvature, and the curvature of the curved corners of the straight edges of the squeegee body varies. When printing is performed using the squeegee, there is a problem in that the thickness of the printed film varies and good printing cannot be performed.

The present invention has been made in view of the above points, and provides a squeegee for a screen printing machine capable of accurately attaching curved surface corner portions having a required curvature and performing good printing. With the goal.

[0007]

In order to achieve the above object, in a squeegee for a screen printing machine of the present invention, a squeegee body is molded by molding, and a cross-sectional circle provided along a straight edge of the squeegee body. It is characterized in that the arc-shaped curved surface corner portion is formed by a mold for molding.

[0008]

In the squeegee having such a structure, since the curved corners of the straight edges of the squeegee body are formed by molding,
It is possible to accurately form a curved corner portion having a required curvature, and the variation in curvature of the curved corner portion can be reduced to about 1/10 of that in the conventional case.

When performing printing, the squeegee is attached to a moving body located above the plate through a holder, and is screen-printed while being pressed against the plate and moving so as to spread the ink thinly. Since the squeegee presses the curved corner portion of the accurate curvature onto the plate to perform printing, good printing can be performed with a printing film having a desired thickness.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a perspective view of a squeegee for a screen printing machine. This squeegee is made of urethane rubber, for example, and is formed into a long plate shape having a constant thickness and width.

Reference numeral 1 denotes a squeegee body, and the squeegee body 1
Curved corners 1a, 1b, 1c, 1d having an arcuate cross-section are formed at the four corners provided along the straight edges in the longitudinal direction.

The radius of the arc cross section of these curved corners, that is, the curvature of the curved corners 1a, 1b, 1c, 1d is set to a constant value, and by forming these curved corners in the mold for molding. The squeegee body 1 is molded at the same time as the molding.

That is, the squeegee body 1 is cast-molded using cast-molding dies 2 and 3 as shown in FIG.
A cavity corresponding to the squeegee body 1 is formed in the casting molds 2 and 3, and a curved corner portion 1 of the squeegee body 1 is formed at a corner portion along a straight edge in the cavity.
Curved surface corner portions having an arcuate cross-section corresponding to a, 1b, 1c, and 1d are formed.

Casting is performed by injecting a urethane rubber material into the molds with the molds 2 and 3 clamped.
The squeegee is molded.

As shown in the drawing, the molded squeegee has curved corners 1a, 1b, 1 having a circular arc-shaped cross section at four corners provided along a straight edge in the longitudinal direction of the squeegee body 1.
c and 1d are formed at the same time, and these curved corners 1a and 1d
b, 1c and 1d have a preset curvature, that is, a radius of an arc cross section, and the error of the radius is within 0.1 mm.

Since the error (variation) of the arc cross section when the curved corners were formed by the conventional polishing was about 1 mm, the curvature errors of the curved corners 1a, 1b, 1c, 1d were as follows:
It will be reduced to about 1/10.

As shown in FIG. 3, the squeegee molded in this manner is mounted on the holder 4 of the screen printing machine by using the mounting plate 5 so that the lower linear edge of the squeegee projects downward. , Mounted on the center line of the holder 4.

The holder 4 is attached to a moving body located above the plate of a screen printing machine (not shown),
As shown in FIG. 4, one curved corner (for example, 1b) of the lower linear edge of the squeegee is pressed onto the plate 6. In this state, the moving body moves in the direction of the arrow in FIG. 4, whereby the squeegee acts so as to spread the ink on the plate placed in front, and the printing material placed under the plate 6 Screen printing is done on top.

As described above, since the squeegee presses the curved corners of the accurate curvature to perform printing, it is possible to perform good printing with a printing film having a desired thickness.

When such screen printing is repeatedly performed and the corners of the squeegee are worn,
By turning the squeegee upside down or left and right and replacing it with the holder 4, the corners of the squeegee for pressing the plate 6 can be used by replacing the curved corners 1b to 1c, 1d, 1a. Therefore, the squeegee can be used for a long life.

FIG. 5 is a graph showing the relationship between the ink viscosity and the printed film thickness when the curvature of the curved corners of the straight edge of the squeegee tip, that is, the radius of the arc cross section, is changed.
Is the radius of the arc cross section of the curved corner is 0.7 mm, and the curve B is
The radius of the arc cross section of the curved corner is 0.4 mm, and the curve C is the radius of the arc cross section of the curved corner is 0.25 mm.

From this graph, it can be seen that if the radius of the arc section of the curved corner of the squeegee is increased, the printed film thickness becomes thicker, and conversely, if the radius of the arc section is decreased, the printed film thickness becomes thinner. Therefore, the radius of the arc cross section of the curved corner of the squeegee, that is, the curvature of the curved corner may be changed according to the viscosity of the ink used and the thickness of the printed film.

[Brief description of drawings]

FIG. 1 is a perspective view of a squeegee showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a squeegee forming die.

FIG. 3 is a perspective view of a squeegee attached to a holder 4.

FIG. 4 is a side view showing a state of screen printing.

FIG. 5 is a graph showing the relationship between the printed film thickness and the ink viscosity when the radius of the arc cross section of the curved corner of the squeegee is changed.

[Explanation of symbols]

 1-squeegee body, 1a, 1b, 1c, 1d-curved corners.

Claims (1)

[Claims] 1. A squeegee body is formed by molding, and curved corner portions having an arcuate cross section provided along the straight edge of the squeegee body are formed by the die for molding. Squeegee for screen printing machine.