JP3339121B2 - Squeegee for screen printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeegee pressed against a plate of a screen printing machine and 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. In order to spread the ink thinly, a rubber plate-shaped squeegee moves above the plate. The printing is performed while spreading the ink thinly on the plate by moving the squeegee pressed against the plate.

[0003]

The squeegee of such a screen printing machine is mounted on a moving body via a holder in an inclined state, and the squeegee lower portion is pressed against a plate by pressing a corner portion of a straight edge at a lower portion thereof. The corner of the pressed straight edge is formed according to the viscosity of the ink to be used or the thickness of the printed film to be printed. That is, it is necessary to change the curvature of the corner of the curved surface.

[0004] For this reason, conventionally, a squeegee of a screen printing machine is formed by molding such that all the corners of the straight edges of the squeegee main body become acute angles (right angles) at the time of manufacture, and this is used for 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 polished with a grinder to form the corner of the squeegee so that a desired curvature is obtained. I was

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

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

[0007]

In order to achieve the above object, a squeegee for a screen printing machine according to the present invention comprises a squeegee body formed by molding and having a cross-sectional circle provided along a straight edge of the squeegee body. A plurality of arc-shaped curved surface corners are formed by a mold.

[0008]

In the squeegee having such a structure, since the curved surface corner of the straight edge of the squeegee body is formed by molding,
A curved surface corner having a required curvature can be accurately formed, and the variation in the curvature of the curved surface corner can be reduced to about 1/10 as compared with the related art.

When printing, the squeegee is attached to a moving body located above the plate via a holder, and screen printing is performed while being pressed against the plate and moving so as to spread the ink thinly. Since the squeegee presses a curved surface corner having an accurate curvature onto the plate to perform printing, it is possible to perform good printing having a printing film of a desired thickness. Screw
Printing is repeated, and the corners of the squeegee are worn out.
The squeegee is turned upside down or left or right
By changing to a holder, multiple curved corners
The tip can be replaced with a new curved corner
The squeegee can be used for a longer life.

[0010]

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

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

Reference numeral 1 denotes a squeegee main body.
The curved corners 1a, 1b, 1c, 1d having an arc-shaped cross section are formed at four corners provided along the linear straight edges in the longitudinal direction.

The radii of the arc-shaped cross sections of these curved surface corners, that is, the curvatures of the curved surface corners 1a, 1b, 1c, 1d are set to constant values, and these curved surface corners are formed in a mold for molding. The squeegee body 1 is formed simultaneously with the molding.

That is, as shown in FIG. 2, the squeegee body 1 is cast-molded using the molds 2 and 3 for casting.
A cavity corresponding to the squeegee main body 1 is formed in the casting molds 2 and 3, and a curved corner 1 of the squeegee main body 1 is formed at a corner along a straight edge in the cavity.
A curved surface corner having an arc-shaped cross section corresponding to a, 1b, 1c, 1d is formed.

The casting is performed by injecting a urethane rubber material into the molds while the molds 2 and 3 are clamped.
A squeegee is formed.

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

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

As shown in FIG. 3, the squeegee formed as described above is mounted on the holder 4 of the screen printing machine by using the mounting plate 5 so that the lower straight edge protrudes downward. , Mounted on the center line of the holder 4.

The holder 4 is attached to a moving body located above a plate of a screen printing machine (not shown).
As shown in FIG. 4, one curved surface corner (for example, 1b) of the lower straight 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 to spread the ink on the plate placed in front thinly, and the squeegee moves on the printing material placed under the plate 6. Screen printing is performed on the top.

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

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

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

From this graph, it can be seen that the larger the radius of the circular cross section at the corner of the curved surface of the squeegee, the thicker the printed film thickness, and conversely, the smaller the radius of the circular cross section, the thinner the printed film thickness. Therefore, the squeegee may be formed by changing the radius of the arc-shaped cross section at the curved surface corner, that is, the curvature of the curved surface corner, in accordance with the viscosity of the ink used and the thickness of the printed film.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a mold for a squeegee.

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 printing film thickness and the ink viscosity when the radius of the arc cross section at the curved surface corner of the squeegee is changed.

[Explanation of symbols]

 1-Squeegee body, 1a, 1b, 1c, 1d-curved surface corner.

Claims (2)

(57) [Claims] 1. A squeegee main body is formed by molding, and a plurality of curved corners having an arc-shaped cross section provided along the linear edge of the squeegee main body are formed by the mold. A squeegee for a screen printing machine. 2. The radius of the circular arc cross section of the curved surface corner is 0.4 m.
2. The screen according to claim 1, wherein
Squeegee for printing press.