Patent ID: 8191472
Filing Date: 2012-06-05
Classification: B41M,H05K

Abstract:
1. A screen-printing method in which a circuit board transferred below a screen mask of a screen-printing apparatus is raised to be retained in contact with an underside of the screen mask, and a squeegee brought into contact with an upper surface of the screen mask is moved so that the circuit board is screen-printed, wherein the screen-printing apparatus is switchable between a normal screen-printing mode which is a control mode for a first screen-printing and a re-printing mode which is a control mode for a second or subsequent screen-printing in which a new print pattern is formed so as to overlap a previous print pattern, the method comprising: in execution of re-printing in which the control mode of the screen-printing apparatus is switched from the normal screen-printing mode to the re-printing mode so that the second or subsequent screen-printing is executed, photographing predetermined portions of a previously printed circuit board (hereinafter referred to as “printed board”) and the screen mask respectively by a camera, recognizing positions of both portions by an image processing technique, compensating a relative positional displacement between the screen mask and the printed board and subsequently, and raising the printed board thereby to bring the printed board into contact with the underside of the screen mask, wherein a raising speed of the printed board at a final stage of the printed board raising operation is rendered lower than a raising speed at a final stage of a circuit board raising operation in the first screen printing so that the printed board is brought into contact with the underside of the screen mask more slowly.