Printing – Stenciling
Reexamination Certificate
1999-12-02
2001-06-05
Hilten, John S. (Department: 2854)
Printing
Stenciling
C101S123000, C101S127100
Reexamination Certificate
active
06240840
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a screen printing apparatus, and more particularly to a screen printing apparatus which is structured such that a printing agent is not left within a screen hole of a mask after printing.
2. Description of the Prior Art
A screen printing apparatus is structured such that a mask is arranged on a plate to be printed such as a printed circuit board and the like, a printing agent such as a creamed solder and the like mounted on the mask is expanded by a squeegee, and a printing is performed at a predetermined position of the plate to be printed via a screen hole provided on the mask.
At a time of printing by the squeegee, a printing agent
103
such as a creamed solder and the like within a screen hole
102
of a mask
101
is taken out from the screen hole
102
only by an own weight of the printing agent
103
itself and an adhesive force as shown in
FIG. 3
when the plate to be printed is peeled out from the mask in accordance with a downward movement of the plate to be printed such as the printed circuit board and the like, so that a power at a time of the printing agent being taken out therefrom is poor and there is a case in which the printing agent is attached to an inner surface of the screen hole
102
and left therein. Further, the printing agent gradually sticks thereto or is expanded around the screen hole at a back side thereof.
Further, there is a case in which the printing agent itself printed on a base plate lacks a sharp property. In this case, reference numeral
104
in the drawing denotes a plate to be printed such as a printed circuit board and the like.
Accordingly, it is necessary to frequently perform a cleaning of the mask while stopping the operation of a machine.
SUMMARY OF THE INVENTION
The present invention is made by taking the points mentioned above into consideration, and an object of the present invention is to provide a screen printing apparatus which is structured such that a printing agent is not left within a screen hole of a mask after printing, thereby dispensing with cleaning of the mask or extending greatly a period required for performing the mask cleaning operation.
In accordance with a gist of the present invention, there is provided a screen printing apparatus comprising the main body of a screen printing apparatus, wherein an upper side within the main body thereof is formed as a chamber which can be sealed by setting a mask supporting table as a boundary, and a pressure within the chamber can be ascended and descended at a desired timing by suitable pressure ascending and descending means.
Further, it is desirable to use an air bag placed at a suitable position within the upper side chamber as the pressure ascending and descending means for the pressure within the upper side chamber of the main body of the screen printing apparatus.
Still further, it is possible to provide a pair of the air bags within the upper side chamber, thereby inflating one of them so as to ascend the pressure and extracting a gas from another air bag after a predetermined time passed so that the pressure may return to the original state. Furthermore, it is possible to use one air bag and repeat an injection and a discharge of the gas.
REFERENCES:
patent: 4519760 (1985-05-01), Norell
patent: 4590854 (1986-05-01), Anderson
patent: 4702165 (1987-10-01), Anderson
patent: 5596925 (1997-01-01), Hasegawa
patent: 5953989 (1999-09-01), Uchiyama et al.
patent: 6138562 (2000-10-01), Hertz et al.
Bacon & Thomas
Grohusky Leslie J.
Hilten John S.
Minami Co. Ltd.
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