JPH07309003A - Screen printing machine - Google Patents

Abstract

PURPOSE:To eliminate the generation of the breakage or irregularity of a printing plate by moving a screen printing machine along a printing direction in contact with the printing material placed on the main upper surface of a printed circuit board without rubbing the printing material. CONSTITUTION:A groove is provided to the side part of a P-plate holding stand 1 or the level base stand provided outside the stand 1 along a printing direction and a pi-shape bar of which the leg length is larger than the value obtained by adding the height of the printing material placed on the P-plate to the depth (h) of the groove is fitted in the groove. Subsequently, since the bar always moves from the rear of a squeegee so as to support a screen S with the movement of the squeegee, a part of the screen plate having the opening part corresponding to a printed image pattern is separated from the surface of the P-plate while printing is advanced to float. By this constitution, the main rear surface of the screen is not brought into contact with the printing material placed on the P-plate and plate separation wherein the upper surface 2 of the P-plate and the main rear surface of the screen are separated is smoothly performed.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing apparatus for depositing a solder paste on a predetermined position by a contact type screen printing before mounting an electronic component on an electronic circuit board.

2. Description of the Related Art In recent years, finer conductor lines have been developed, and for screen printing on an electronic circuit board, a screen (hereinafter abbreviated as screen) as a print medium and a printed circuit board (as a printed material) Hereinafter, abbreviated as P-plate)
In addition to contact-type screen printing (hereinafter abbreviated as contact printing) in which the upper surface is closely contacted and printed, a gap-type screen printing (hereinafter, gap) is performed in which a gap is provided between the screen and the P-plate upper surface. Printing and abbreviation)
Is also frequently used. In gap printing, as the squeegee moves slidingly over the upper surface of the screen, the tent effect of the screen causes the main surface and lower surface of the screen to move away from the upper surface of the P-plate. On the other hand, in the contact printing, after the printing is finished, the screen is floated or the P
-The board is lowered to separate the two.

[Problems to be Solved by the Invention] In such contact printing, the screen and the P-plate are separated from each other after the printing material to be mounted on the upper surface of the P-plate is printed. It was liable to be caused by the blemishes and caused "chips" and "unevenness" in the printing plate. It can be said that this, on the contrary, hastened the advent of gap printing.

The present invention has been made in view of the above problems, and the screen behind the squeegee floats away from the upper surface of the P-plate as the squeegee or the squeegee device moves during printing. The present invention provides a screen printing apparatus having the above-mentioned structure.

[Means for Solving the Problems] In order to solve the above problems, in the screen printing apparatus according to the present invention, first, a U-side is formed along the printing direction at the side portion of the P-plate holder.
A horizontal bar that has a groove and has legs that are longer than the depth of the groove.
Is placed behind the squeegee.

Next, the printing apparatus according to the present invention has a P-
On the outside of the side of the plate holder, a kind of flat base is provided, and the same groove and bar as above are provided on the upper surface.

[Operation] In the printing apparatus according to the present invention, P
-A groove is provided along the printing direction either on the side of the plate holder or on a level base provided outside thereof, and the length of the leg of the groove is set to the depth of the groove on the P-plate. Insert a Π-shaped bar larger than the height of the printed printing material, and as the squeegee moves, it always moves from behind it to lift the screen, so that the printing progresses while printing. A portion of the screen plate having openings corresponding to the completed image pattern is floated away from the P-plate upper surface,
The so-called "plate separation" in which the upper surface of the P-plate and the lower surface of the main surface of the screen are separated without the main surface and lower surface of the screen coming into contact with the printing material placed on the P- plate is smoothly performed. Become.

[Embodiment] The gist of the present invention will be described below.
An example will be described with reference to the drawings. Figure 1
[Fig. 3] shows a main part configuration of an embodiment of a printing apparatus according to the present invention, and is a vertical cross-sectional view in the printing surface as viewed from the printing direction (P). In the figure, 1 is P in the central portion in the width direction.
-A holding base of a P-plate having a shallow U-shaped groove having the same depth as the thickness of the plate, a dotted line 2 indicates the upper surface of the main surface of the P-plate mounted on the holding base, and a thick solid line 3 indicates On the upper surface of the side of the holding table in the width direction, the subscripts L and R of the 3 are left and right (hereinafter the same), 4 is a bar having a length narrower than the width of the screen and larger than the occupied width of the image pattern to be printed. And a pedestal having a height (H) larger than the depth (h) of the U-shaped groove (G) provided on the left and right ends of the bar and provided in 3 along the printing direction are integrally configured in a Π shape. It was done. Reference symbols A and B denote cutting lines for removing the bar at the center of the Π-shaped structure, and as a result,
The pair of left and right T-shaped structures can be synchronized with each other to perform the same function as in the case of the above-mentioned Π shape, which is effective when the P-plate is relatively narrow.

FIG. 2 shows another embodiment of the printing apparatus according to the present invention. The difference from FIG. 1 is that the groove for guiding the Π-shaped pedestal is different from the upper surface of the P-plate holding base. Instead, it is only formed on the upper surface of the leveling base (6) provided outside the side of the holding base. That is, the thick solid line (6 _L ,
6 _R ) means the upper surface of the base. In order to clarify this difference, each reference numeral corresponding to FIG. 1 is primed. However, the wavy line (W) in the figure is
It is meant that the structure of the lower part of the base is omitted because it is essentially unrelated to the present invention.

In both figures, the relationship between the depth of the U-shaped groove and the height of the pedestal satisfies the following equation. That is, H (H ')-h (h') = D (D ') (1) D (D')> d (d ') (2) where H is the pedestal height and h is the groove depth. Here, D represents the difference, and d represents the maximum value of the height of the printing material placed on the P- plate as a guide. The prime in both formulas is shown in Figure 2.
It corresponds to the case of. According to the formula (2), when the above-mentioned Π-shaped structures move along with the printing direction while supporting the screen from the rear of the squeegee, the printing material just placed on the front of the Π-shaped structures is moved to the front. It is guaranteed that contact and abrasion do not occur.

In contact printing, as a matter of course,
Before printing, the lower surface of the main surface of the screen and the upper surface of the P-plate are in close contact with each other. Therefore, it is necessary for the structure to lift the screen plate at the same time when the squeegee is started by the start of printing. This mechanism is shown in FIG. In the position of the mark a, the structure b corresponds to just before the start and after printing, screen (S), each S _a which is支揚to the structure in this _position, in S _b, of course they squeegee or squeegee This is the part behind the device (5). The curved dotted line (G) is the bottom surface of the groove described above, and is parallel to the tangent plane with the screen plate and the P-plate after the position of b.
w has the same meaning as W in FIG.

In addition to the above embodiments, various configurations and structures are allowed without departing from the scope of the present invention, and are not particularly limited to the drawings of the above embodiments. . For example, the drive device for the above structure may be an ordinary motor, and its illustration is omitted because it does not directly relate to the spirit of the present invention, including the synchronous circuit with the squeegee device.

[Effects of the Invention] As can be easily understood from the above description, the present invention has the following effects in contact type screen printing.

A groove is formed along the printing direction into which the pedestal of the Π-shaped structure straddling the widthwise direction is inserted, either on the side portion of the P-plate holding base or on the leveling base provided on the outside thereof, and printing is performed. At the start, since the above structure raises the screen behind the squeegee, the plate separation is smoothly performed, and as a result, a good printing plate without "chips" or "unevenness" is obtained.

Instead of the Π shape, a pair of left and right T-shaped structures with the central bar removed can achieve the same effect as in the preceding paragraph.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part configuration showing an embodiment of a printing apparatus.

FIG. 2 is a vertical cross-sectional view of a main part configuration showing an embodiment of a printing apparatus.

FIG. 3 is a lateral cross-sectional view of the main configuration showing the functions of the embodiment of the printing apparatus.

[Explanation of symbols]

1,1 'Printed circuit board holder 2,2' Printed circuit board main surface upper surface 3 _L , 3 _R Printed board holding table side edge surface upper surface 4,4 'Lifting bar 5 Squeegee (squeegee device) 6 _L , 6 _R Leveling base table top P printing direction S screen _{G, G L, G R,} G'L, G'R grooves (guide) H, the height h of h'pedestals, h'groove depth a, b section line

Claims (2)

[Claims] 1. A shallow U-shaped groove-shaped holding base of the printed board having a depth equal to the thickness of the printed board as a material to be printed and a width equal to the width of the board, along the printing direction on the widthwise side upper surface. U-shaped groove is provided, and a bar having a length narrower than the width of the screen as a print medium and larger than the width occupied by the image pattern and a height larger than the depth of the left and right grooves of the holding table are provided at the left and right ends of the bar. The Π-shaped structure integrally attached with the pedestal has the pedestal moving in the printing direction as a lifting bar capable of lifting the screen behind the squeegee along the printing direction. It is fitted into the groove as a guide for printing and is synchronized with the movement of the squeegee device along the printing direction, and the printing material placed on the upper surface of the main surface of the printed circuit board does not come into contact with the printing material and is printed without rubbing. Can move along a direction Cormorant configured contact printing apparatus in a screen printing 2. A shallow U-shaped groove having the same depth as the thickness of a printed circuit board as a material to be printed and the same width as the width of the substrate, and is approximately flush with the upper surface of the main printed surface of the printed circuit board. A U-shaped groove is provided along the printing direction on the upper surface of the side in the width direction of the pair of left and right rail-shaped leveling bases whose vertical position is variable, and is narrower than the width of the screen as a print medium and smaller than the image pattern occupied width. A bar having a long length and pedestals having heights larger than the depths of the left and right grooves of the leveling base are attached to the left and right ends of the bar, and a Π-shaped structure integrally formed is formed in a printing direction. The pedestal is inserted into the groove as a guide for moving in the printing direction as a lifting bar capable of lifting the screen behind the squeegee, and is synchronized with the movement of the squeegee device along the printing direction. Shitsu, the above print base Primary table in contact with the printing material to be placed on the upper surface without scraping, the printing device in configured contact type screen printing to be movable along the printing direction of the