screen printing device

Abstract

The invention aims to provide a screen printing device which can stably supply a cleaning solution to cleaning sheets. A cleaning mechanism is arranged on the screen printing device. An air-driven diaphragm type pump (35) is used to intake liquid to be supplied to a cleaning solution (32) of a tank (33). The cleaning solution which is sent to a discharge nozzle via a discharge tube (31) connected with a discharge port (37) of the pump (35) is supplied to a system. The screen printing device has an air supply control part using a magnetic valve (43) to control the supply of drive air to a valve (42) with an air-driven valve mechanism of the discharge tube (31) and the pump (35). When the pump works, the valve (42) is opened to supply the cleaning solution (32) to the discharge tube (31), and when the pump stops, the valve is closed to prevent the cleaning solution (32) from flowing backward in the discharge tube (31). As a result, the screen printing device can prevents faults of the existing device due to poor performances of valve.

Description

technical field [0001] The present invention relates to a screen printing device for printing paste such as solder paste or conductive paste on a substrate. Background technique [0002] As a method of printing a paste such as solder paste or conductive paste on a substrate in an electronic component mounting process, screen printing in which the paste is transferred to the substrate through pattern holes provided in a mask is widely used. During the printing operation, since the solder paste overflowing from the printed part adheres to the substrate under the mask, or the solder paste that has not been completely transferred to the substrate remains in the opening of the mask, Therefore, it is necessary to perform cleaning work for absorbing or wiping off these solder pastes at predetermined intervals. [0003] Therefore, currently, the screen printing apparatus is provided with a cleaning mechanism that wipes and cleans the lower surface of the mask with a cleaning sheet....

AI Technical Summary

Problems solved by technology

[0006] However, in the cleaning mechanism with the above configuration, due to the structure of the cleaning liquid discharge system, there are the following difficulties in stably supplying the cleaning liquid

That is, the diaphragm pump driven by air pressure is prone to liquid leakage due to the unstable operation of the suction valve and discharge valve built in the pump with a simple structure, and in the pump, the diaphragm pressurizes the washing liquid. Air stagnation and the like are likely to occur in the pressure chamber, so it is difficult to stably ensure the correct discharge amount

[0007] In addition, the check valve combined with this pump to prevent the backflow of washing liquid has a structure in which the valve body is pressed against the valve seat by a spring, so that the contact surface between the valve body and the valve seat is washed by the washing liquid. In the case of adhesion of organic components, etc. contained in the valve body, the normal operation of the valve body cannot be performed, and it cannot function as a check valve.

In this way, in the wet cleaning mechanism equipped with the conventional screen printing device, there is a problem that it is difficult to stably supply cleaning liquid to the cleaning sheet.

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