JPH0462058A - Screen printing machine - Google Patents

Abstract

PURPOSE:To permit a uniform cleaning of a screen without leaving any part of its surface uncleaned by providing a screen cleaning mechanism so constructed as to be slidably movable while the screen surface is being sucked thereby and with a cleaning member held thereagainst with an elastic body. CONSTITUTION:A solvent coating nozzle 19 is provided on the upper surface of a cleaning member 18 such as cloth to impregnate this member 18 with a solvent and, on the lower surface thereof, a cleaning squeegee 20 having a flat plate-like elastic body 20a and a vertically movable suction block 21 are provided in contact therewith in a slidably movable manner. The cleaning squeegee 20 and the suction block 21 have the length almost the same as the width of a screen 13. the cleaning member 18 is about as wide as the screen 13, rolled up on roll 23 and connected at its end to a take-up roll 22. The aforesaid cleaning mechanism thus constructed is located in a position lower than the screen 13 and in a standby position spaced from the lower part thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screen printing machine. The present invention particularly relates to a screen printing machine suitable for screen printing that prints conductive paste, cream solder, etc. on a printed circuit board in an electronic circuit board assembly process.

[Prior Art] In recent years, electronic circuits on printed circuit boards have become smaller and more dense as their products have become lighter, thinner, shorter and smaller. Therefore, screen printing machines used for printing on such printed circuit boards must be equipped with an automatic screen cleaning mechanism to prevent printing defects from occurring even during continuous printing or to improve printing accuracy. is becoming mainstream.

Conventionally, this type of screen printing machine
A configuration as shown in Japanese Patent No. 853 was common. The configuration will be explained below with reference to FIGS. 3 and 4.

FIG. 3 is a schematic sectional view of the main parts of a conventional screen printing machine, showing a state in which printing is performed using a conventional screen printing machine equipped with a cleaning mechanism. Further, FIG. 4 is a schematic cross-sectional view of the main parts of the conventional screen printing machine, showing a state in which the cleaning mechanism is activated to clean the screen in the screen printing machine of FIG.

In FIGS. 3 and 4, 1 is a squeegee, 2 is a screen, 3 is a printing paste, 4 is a substrate to be printed, 5 is a solvent application nozzle of a cleaning device, 6 is a cleaning member such as cleaning paper or cloth, and 7 is the elastic body 7a
8 is a cleaning squeegee equipped with a cleaning squeegee; 8 is a take-up roll for cleaning materials such as cleaning paper;
10 is a cleaning member winding body on the supply side of a cleaning member 6 such as cleaning paper, and 10 is a printing material 4.
This is a stage that can move up and down to just below the screen 2.

As shown in Figure 3, in the printing process, stage 10
holds the printing material 4 and rises to just below the screen 2,
By sliding the squeegee 1 in contact with the screen 2, the printing paste 3 pushed out from the screen 2 is printed on the printing material 4. In this case, a cleaning squeegee 7, a cleaning member take-up roll 8
A cleaning mechanism consisting of a cleaning member winding body 9, and a solvent application nozzle 5 is arranged in a standby position at a position slightly removed from below the screen 2 of the screen printing machine.

After printing a predetermined number of sheets, as shown in FIG. 4, the stage 10 moves downward, and a cleaning member 6, such as cleaning paper, soaked in a solvent for wiping off the printing paste is applied by a solvent application nozzle 5. moves forward while being pressed against the screen 2 by a cleaning squeegee 7 having an elastic body 7a, and wipes off the surface of the screen 2 that comes into contact with the printing material 4. After wiping, the take-up roll 8 of the cleaning member 6 takes up a predetermined amount of the cleaning member 6, such as dirty cleaning paper, and the cleaning mechanism retreats to return to its original position as shown in FIG.

[Problems to be Solved by the Invention] In the configuration of such a conventional screen printing machine, when the elastic body 7a of the cleaning squeegee 7 presses the cleaning member 6 such as cleaning paper against the screen 2, the screen 2 Since it is an extremely thin sheet, the screen 2 will warp and the cleaning squeegee 7 will
There was a problem in that the cleaning member 6 such as cleaning paper did not come into uniform contact with the cleaning member 6 in the longitudinal direction (perpendicular to the paper surface in the drawing). Therefore, some residue was left unwiped, and the cleaning function could not be sufficiently performed.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a screen printing machine equipped with a cleaning mechanism that achieves a uniform wiping effect.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a screen printing machine that prints a printing paste on a screen onto a printing material using a squeegee, in which the screen comes into contact with the printing material. a cleaning member on a side surface, and an elastic body that can slide along the back surface of the cleaning member while pressing the cleaning member against the screen;
A screen printing machine, comprising a suction block that can slide along the back surface of the cleaning member while vacuum suctioning the screen surface downward through the cleaning member, and is movable below the screen. It has a structure.

[Function] With the above-described configuration, the screen printing machine of the present invention can press and slide the cleaning member against the screen surface using an elastic body while vacuum suctioning the screen surface, so that it comes into contact with the printing material on the screen. the side surface,
It can be wiped off while being brought into uniform contact with a cleaning member such as paper or cloth, and can perform a uniform cleaning function without leaving any residue.

[Examples] Examples of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing the entire screen printing machine of the present invention. FIG. 2 is a schematic sectional view of the main parts of the screen printing machine of the present invention, showing the state when the cleaning mechanism is activated. The printing conditions during screen printing using the apparatus of the present invention are almost the same as those shown in FIG. 3, so illustration thereof will be omitted.

As shown in the figure, the screen printing machine has a print head section 1
1, a screen holder 12, a screen 13, a supply conveyor 14 for supplying the printing material to the lower part of the screen, and a feeding conveyor 14 for moving the printing material supplied from the supply conveyor 14 to just below the screen, and during printing, the printing material is a stage 25 that is movable up and down to hold the substrate directly below the screen 13; a discharge conveyor 15 for discharging the printed material after printing; and a cleaning mechanism 16.
Furthermore, the cleaning mechanism 16 is arranged in a waiting state at a position lower than the height of the screen 13 and at a position removed from the lower part of the screen 13. The cleaning mechanism 16 includes a cleaning member 18, a solvent application nozzle 19, a cleaning squeegee 20 having an elastic body 20a, a vacuum suction block 21, a winding roll 22 for the cleaning member 18, and a winding body for the cleaning member 18. It consists of 23.

Cleaning materials such as cleaning paper and cloth 1
A solvent application nozzle 19 capable of dissolving the printing paste 26 is provided at the upper part of the printing paste 8, and the cleaning member 18, such as cleaning paper or cloth, is impregnated with the solvent. Further, a flat elastic body 20a is provided at the bottom of the cleaning member 18.
A vacuum suction block 21 connected to a cleaning squeegee 20 and a vacuum pump (not shown), etc., is movable up and down, and is arranged so that it can slide in contact with the lower surface of the cleaning member 18. has been done. The cleaning squeegee 20 and the vacuum suction block 21 have a length that is approximately the same as the width of the screen 13, and the width of the cleaning member 18 is also approximately the same as the width of the screen 13. The cleaning member 18 is rolled up on a roll-up body 23. Further, the tip of the cleaning member 18 is connected to a take-up roll 22, and after cleaning, a predetermined amount of the portion used for use is wound up on the take-up roll 22.

To explain the operation of the above configuration, first, the cleaning mechanism 16 is not activated and is kept at a standby position located below the screen 13 as described above. Printing follows the usual screen printing method. The printing material is supplied from the supply conveyor 14 onto the stage 25 below the screen 13. The stage 25 is raised and placed directly below the screen, and the printing paste 26 on the screen 13 is moved with a squeegee. 2
After printing is completed by sliding the stage 25, the printed material is separated from the screen 13 by the lowering of the stage 25, and then discharged by the discharge conveyor 15. After printing a predetermined number of sheets, the winding roll 22 unwinds and stretches the cleaning member 18 such as cleaning paper from the cleaning member roll-up body 23 while impregnating the cleaning member 18 with solvent from the solvent coating nozzle 19, and then the cleaning member 18 is unrolled and stretched by the cleaning squeegee 20 and vacuum suction. It moves forward under the screen 17 together with the block 21. Here, the cleaning squeegee 20 and the vacuum suction block 21 are raised, and the cleaning member 18 is moved up by the cleaning squeegee 20.
The elastic body 20a attached to the tip of the screen 1
Press it to 3.

Since the screen 13 is attracted to the vacuum suction block 21 via the cleaning member 18 and pulled downward, the elastic body 20a of the cleaning squeegee 20 comes into close contact with the cleaning squeegee 20 uniformly in its longitudinal direction. In this state, the screen 13 is cleaned by sliding the cleaning squeegee 20 and the vacuum suction block 21 along the surface of the screen 13 via the cleaning member 18. When cleaning is completed, the take-up roll 22 moves the cleaning squeegee 20 to the initial waiting position while winding up the dirty portion of the cleaning member 18 used for cleaning.
, are returned together with the vacuum suction block 21.

In the present invention, it is preferable that at least the portion of the vacuum suction block 21 that comes into contact with the cleaning member 18 is made of an elastic body. Also, cleaning squeegee 2
0 elastic body 20a, the elastic body of the part of the printing squeegee 24 that contacts the screen 13, and the elastic body of the vacuum suction block 21 are usually made of polyurethane rubber, but the purpose of the present invention can be achieved. Of course, an elastic body made of other appropriate materials may be used.

[Effects of the Invention] According to the present invention, since the surface of the screen that comes into contact with the printed material can be wiped while being brought into uniform contact with the cleaning member, a uniform cleaning function is achieved with no residue left after wiping, and the cleaning function is high. We can provide a screen printing machine that supports precision printing.

Further, since a vacuum suction block is used, an additional effect of removing clogging of the screen is also exhibited.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the entire screen printing machine according to an embodiment of the present invention, FIG. Fig. 3 is a schematic sectional view of the main parts of a conventional screen printing machine showing a state in which printing is performed using a screen printing machine equipped with a conventional cleaning mechanism, and Fig. 4 shows the cleaning mechanism of the screen printing machine of Fig. 3. 1 is a schematic cross-sectional view of a main part of a conventional screen printing machine, showing a state in which a screen is cleaned by applying pressure. DESCRIPTION OF SYMBOLS 13... Screen, 18... Cleaning member, 19... Solvent application nozzle, 20... Cleaning squeegee, 20a... Elastic body, 21... Vacuum suction block, 22... Winding up Roll, 23... Cleaning member winding body, 24... Squeegee, 25...
・Stage, 26...Print paste. Figure 1

Claims (1)

[Claims] In a screen printing machine that prints the printing paste on a screen onto a printing material using a squeegee, a cleaning member is placed on the surface of the screen that comes into contact with the printing material, and while pressing the cleaning member against the screen. A screen includes an elastic body that can slide along the back surface of the cleaning member, and a suction block that can slide along the back surface of the cleaning member while vacuum suctioning the screen surface downward through the cleaning member. A screen printing machine characterized by being movable downward.