JPH05193100A - Circular arc surface screen frame for screen printing - Google Patents

Abstract

PURPOSE:To provide the subject screen frame equipped with a circular arc surface screen printing plate constituted so as to be capable of performing the same beautiful printing as a screen printing plate using an extensible screen composed of nylon or the like and also performing thick film printing suitable for solder printing or repeated printing of twice or more. CONSTITUTION:A screen 2 is provided to the bottom surface of a rectangular frame 1 consisting of parallel front and rear frame woods 1a, 1b whose side surface shapes are formed into a circular arc shape under tension to provide a circular arc surface screen frame A having a circular arc surface-shaped screen and a printing plate of an objective pattern is formed on the circular arc surface screen 2 of the circular arc surface screen frame A. A squeezee block 8 provided with two rollers 5a, 5b and a squeezee holder 7 is provided and two rollers 5a, 5b are placed on the upper surfaces of the front and rear frame woods 1a, 1b of the circular arc surface screen frame A and a squeezee 6a or 6b is provided in parallel to a printing surface 4 in such a state that the leading end thereof is in contact with the screen 2a in a freely reciprocally movable manner to constitute a printer.

Description

Detailed Description of the Invention

[0001]

2. Description of the Related Art Recently, when an electronic component is soldered and mounted on a printed circuit board, solder is printed on the printed circuit board by screen printing means, and the electronic component is mounted and temporarily adhered to heat before the solder dries. It is widely practiced to process and solder. Thus, these solder printing, electronic component mounting, solder heating, etc. are usually performed as each step of a continuous production line.

That is, when performing the above-mentioned screen printing, the solder corresponds to the printing ink, but a paste-like paste having a considerably higher viscosity than the ordinary printing ink is used and the soldering performance is improved. Thick film printing is required in order to increase the printing efficiency, and screen printing means is used for this purpose.For solder printing, stretchable woven screens such as nylon, tetron and silk are usually used for screen printing. Is inappropriate.

A metal screen, which is a woven fabric of steel fine wires, is also not stretchable, but its texture is unsuitable because it causes pinholes in the printing solder. Therefore, at present, etching is mainly performed on a thin metal plate. A metal screen in which fine holes are formed in a mesh shape is used.
However, since the metal screen is also made of a thin metal plate,
Naturally, unlike woven cloth screens such as nylon, it does not have elasticity.

Generally, in screen printing, after a squeegee presses ink through a screen printing plate toward the printing surface to print, the printed portion of the printing surface (the portion immediately after passing the squeegee) is immediately separated from the printing surface. This is the maximum requirement for clean printing, and in the case of stretchable screens such as nylon, there is a clearance from the initial printing surface so that the squeegee tip pushes ink through the screen printing plate during printing. When the screen is stretched, it comes into contact with the printing surface to perform printing, and at the same time when the squeegee passes (the printing of that portion is completed), the screen shrinks and restores immediately, and immediately leaves the printing surface, so that clean printing is possible. It is a thing.

However, since the metal screen has no elasticity, it cannot operate as described above. Therefore, recently, a combi-screen printing plate (see FIG. 3) is being used.
This is because the stretchable screen 2b of the conventional screen frame A'provided by stretching the stretchable screen 2 made of nylon or the like on the bottom surface of the rectangular frame 1'is used as a measure against bitterness for imparting stretchability to the metal screen. A metal screen 2a (provided by etching) is installed in the central portion, that is, a stretchable screen 2b is stretched with a set width between the periphery of the metal screen 2a and the rectangular frame 1. The metal screen printing plate does not have elasticity similar to that of the elastic screen printing plate.

However, the combination screen printing plate has the following problems. That is, since a stretchable screen portion with a set width (for example, 10 cm inside and outside) must be formed around the metal screen, it is necessary to increase the area of the entire screen frame or reduce the size of the metal screen. Since it requires a large installation space, it is difficult to install it on a line for manufacturing printed circuit boards, and the latter has a drawback that the size of the metal screen is limited.

Since the metal screen itself does not have the elasticity even if it has elasticity, the entire surface of the metal screen printing plate comes into close contact with the printing surface when pressed with a squeegee during printing, and the plate separation must be done at the same time. Not get
The finish of printing is poor, it is not suitable for precision pattern printing, and it is difficult to get clearance because thick film printing or repeated printing more than two times cannot be performed. There were a number of problems such as the need to clean the plate after each printing.

[0008]

SUMMARY OF THE INVENTION The present invention has been made mainly for the purpose of solving the problems of the conventional metal screen printing frame, and is a screen printing plate using a non-stretchable metal screen. In addition to the same beautiful printing as the screen printing plate using a stretchable screen, such as thick film printing suitable for solder printing and arc-shaped screen printing plate that can be repeated twice or more The present invention effectively solves the above-mentioned conventional problems by providing an arc surface screen frame for screen printing.

[0009]

That is, according to the present invention, in a screen frame for screen printing in which a screen is stretched on the bottom surface of a rectangular frame, a front and rear frame is formed by a side arc-shaped frame. A screen is stretched on the bottom of the frame to provide an arc surface screen frame having an arc surface screen,
The conventional problems are solved by an arc surface screen frame for screen printing, which is a printing plate having a target pattern formed on the arc surface screen.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. In a screen frame for screen printing, which is formed by stretching a screen 2 on the bottom surface of a rectangular frame 1, parallel front and rear frames 1a, 1b are provided. A screen 2 is stretched on the bottom surface of a rectangular frame 1 formed of a frame having an arc-shaped side surface to provide an arc surface screen frame A of the present invention having a screen having an arc surface. A printing plate having a target pattern is formed on the arc surface screen 2 of the screen frame A.

In the arc-shaped screen frame A of the present invention having the above-mentioned structure, the screen stretched on the bottom surface of the rectangular frame 1 having a side arc shape is mainly a stretchable screen 2b made of a woven fabric of nylon, tetron, silk or the like. The non-stretchable metal screen 2a is used, and the metal screen is a metal thin plate with fine holes formed in a mesh shape by etching, or a metal fine wire woven cloth. That is, in the present invention, in addition to the conventional method, the elastic screen 2b made of nylon or the like is used to provide the arc-shaped screen frame. In particular, the non-stretchable metal screen 2a (provided by etching) is used for solder printing. The arc-shaped screen frame is provided. Of course, it is also possible to provide the arc surface screen frame using a metal wire woven cloth depending on the application.

The outline of the construction of the embodiment of the printing apparatus using the arc surface screen frame A of the present invention will be described below. The other end of the belt 3a having one end bonded to the right frame 1c of the arc surface screen frame A is Printing surface 4 along the arc surface of front and rear frame trees 1a, 1b
And the other end of the belt 3b having one end attached to the left frame 1d of the arc-shaped screen frame A along the arc surfaces of the front and rear frame 1a and 1b and crossing the belt 3a. While being tightly bound to the right end of the printing surface, the arc surface screen frame A is arcuated in a seesaw shape at a fixed position on the printing surface 4 by guiding the side surface arc shape front and rear frame trees 1a and 1b in the bottom arc shape. Prepare to rotate freely.

Two rollers 5a and 5b are placed on the upper surfaces of the front and rear frame members 1a and 1b with a space therebetween.
5b is provided so as to reciprocate in parallel with the printing surface 4 together with the squeegee 6, and the tip of the squeegee 6 is always an isosceles 3 formed by the center points of the two rollers 5a and 5b and the three points of the tip of the squeegee. Prepare to be at the top of a polygon.

When a reciprocating printing device is provided, the left and right squeegees 6a and 6b are provided at the lower end of the squeegee holder 7.
Are installed parallel to each other, and the squeegee holder 7 is rotated about the pivot 7a by a set angle to form left and right squeegees 6a and 6b with the respective center points of the two rollers 5a and 5b. Be prepared to switch to the position.

Further, a squeegee block 8 to which both of the two rollers 5a and 5b and the squeegee holder 7 are attached is provided, and the squeegee block 8 is attached to the two rollers 5a and 5b.
a and 5b are front and rear frame trees 1a and 1b of the arc surface screen frame A.
The printing device is configured to be reciprocally movable in parallel to the printing surface 4 with the tip of the squeegee 6a or 6b in contact with the screen 2a.

For convenience of cleaning and managing the arc surface screen frame A, for example, only the squeegee block 8 is
It is provided so as to be separated from the arc surface screen frame A and detached or moved upward or sideways.

The radius (R) of the circular arcs of the front and rear frame trees 1a and 1b is made as large as possible according to the printing accuracy, and is closer to a straight line. However, the smaller the radius is, the better the pattern printing reproducibility and the thicker the printing. 2 in the example
It is 50 to 300 mm.

[0018]

The plate of the target pattern is formed on the metal screen 2a of the arc surface screen frame A of the present invention to provide a screen printing plate having an arc surface.

Ink (solder paste) is put in the frame,
When moving the squeegee block 8 from right to left, the roller 5
a and 5b move together with the squeegee holder 7, and the movement of the rollers 5a and 5b causes the arc-shaped screen frame A to rotate in a seesaw manner from right to left, and the tip of the squeegee 6a is printed on the printing surface 4 through the screen printing plate. Printing is performed by pushing out (solder paste), and at the same time as the end of printing (the tip of the linear squeegee 6a moves), the arc-shaped screen frame rotates and rises by the movement of the rollers 5a and 5b, and the printing plate immediately separates from the printing surface. To do.

When printing (forward) by moving the squeegee block 8 from right to left is completed, the squeegee holder 7 is moved to 7a.
When the squeegee block 6b is positioned at the apex by pivoting around the pivot as a fulcrum, and then the squeegee block 8 is moved from left to right, the rollers 5a and 5b and the squeegee 6b move from left to right, and at the same time, the arc surface screen frame A Rotates in a seesaw fashion from left to right, and printing (backward) is performed on the printing surface 4.

At the time of the above-mentioned reciprocal printing, the arc surface screen frame A
Is crossed from the left and right frame trees 1d and 1c and is tied to the left and right end portions of the printing surface 4 and the like with belts 3b and 3a.
See-saw rotation in right-to-left and left-to-right direction,
The installation position does not deviate and is kept in a fixed position.

When the arc-shaped screen frame A is to be cleaned, repaired, replaced, etc., the squeegee block 8 as a whole may be removed upward or moved laterally by an appropriate means to move the arc-shaped screen frame A upward and upward. Try to open around.

[0023]

[Effect] A screen (particularly a metal screen) is stretched on the bottom of a screen frame in which front and rear frame trees are formed in a side arc shape, and a screen frame with an arc surface is provided, and a printing plate is formed on the arc surface screen. Since printing is performed by rotating the arc surface screen frame in a seesaw manner by a roller or the like in synchronization with the movement of the squeegee, the arc surface screen (printing plate) and the printing surface are aligned on a straight line. As soon as the squeegee tip comes into contact with the squeegee, the ink (solder) is extruded from the tip of the squeegee → The arc surface screen printing plate is separated from the printing surface immediately after the completion of the linear printing. In addition to being able to perform beautiful printing ideal for screen printing, it is also possible to use non-stretchable screen printing plates such as metal screens due to the above immediate plate separation action. There are very soo the features capable of performing as good as printing and over printing with conventional stretch screen printing plate.

Even when a non-stretchable screen such as a metal screen is used, a clearance can be set between the screen and the printing surface, and the plate separation is extremely good as described above. The above thick film printing can be performed, and this is particularly suitable for solder printing in which thick film printing is required.

Further, due to the features described in the preceding paragraph, it is possible to easily perform printing on a printed material having a slight unevenness on the surface, and it is possible to perform printing more than once on a printed material printed once. It is also possible to print another pattern for the second time on the open portion of the print pattern for the first time. Conventionally, it is completely impossible to perform the second solder printing on the open portion of the pattern of the printed circuit board on which the solder printing is performed, because the solder printing is a thick film, but in the present invention, this is also possible. It has become possible.

Since the arcuate screen screen frames are attached by the belts that are cross-bonded to each other, the guides of the arcuate surface rotate left and right in a seesaw fashion, but do not deviate from the set position.
Therefore, accurate printing without misalignment can be performed.

The seesaw type rotary movement of the arc surface screen frame is performed by parallel movement (with respect to the printing surface) of two rollers provided at intervals, and the tip of the squeegee is the center point of each of the two rollers. Since it is positioned at the apex of the isosceles triangle formed by the squeegee tip, the squeegee tip (one straight line) is located on the line of line contact between the arc surface screen frame and the printing surface that make line contact on one straight line. As a result, it is possible to always perform highly accurate printing without any error.

Unlike the conventional combi-screen frame, it is not necessary to form a composite structure of a stretchable screen and a non-stretchable screen, so that the manufacturing is easy and the cost can be remarkably reduced, and in the case of the arc-shaped screen frame of the present invention. Since the entire surface of the arc surface screen can be used as a printing plate, it is easy to increase the size of the screen printing plate, and in particular, it is possible to miniaturize it for solder printing. There is a great advantage that it can be easily installed and installed on the line.

Since the plate separation is performed almost at the same time as the printing is completed, the ink stain on the printing plate, especially the ink stain on the back surface of the plate can be reduced to several tenths, which is different from the conventional case. Could be improved significantly.

Since the squeegee holder having the two squeegees and the two rollers are both mounted on the squeegee block so that the squeegee block can be removed or moved, the arc surface screen frame is completely opened above and around the screen frame. In that state, cleaning and other maintenance management can be performed,
In this respect as well, work efficiency could be improved.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of an arc surface screen frame of the present invention,
FIG.

FIG. 2 is a front view showing a schematic configuration of an embodiment of a printing apparatus having an arc surface screen frame according to the present invention.

FIG. 3 is a front view, a plan view and a cross-sectional view of a conventional combination screen frame.

[Explanation of symbols]

A present invention arc surface screen frame A'conventional combination screen frame 1 present invention rectangular frame 1'conventional rectangular frame 1a front frame tree 1b rear frame tree 1c right frame tree 1d left frame tree 2 screen 2a metal screen (non-stretchable) Screen, metal screen made by etching) 2b Elastic screen such as nylon woven cloth 3a, 3b Belt 4 Printing surface 5a, 5b Rollers 6, 6a, 6b Squeegee 7 Squeegee holder 7a Pivot 8 Squeegee block

Claims (7)

[Claims] 1. A screen frame for screen printing, comprising a rectangular frame and a screen stretched on the bottom of the rectangular frame. An arc surface screen frame for screen printing, wherein an arc surface screen frame having an arc surface screen is provided, and a printing plate having a target pattern is formed on the arc surface screen. 2. A screen stretched on the bottom surface of a rectangular frame having an arcuate side surface is mainly a non-stretchable metal screen in addition to a stretchable screen made of a woven fabric of nylon, tetron, silk or the like. The arc-shaped screen frame for screen printing according to claim 1, wherein the metal screen is a thin metal plate having fine holes formed in a mesh shape by etching or a woven cloth of fine metal wires. 3. The other end of the belt, one end of which is attached to the right end of the arc surface screen frame, is tightly attached to the left end of the printing surface along the arc surface of the front and rear frame trees, and at the left end of the arc surface screen frame. The other end of the belt having one end tied is tightly tied to the right end of the printing surface along the arc surface of the front and rear frame trees and while intersecting with the belt, and the arc surface screen frame is placed at a fixed position on the printing surface. The arc-shaped screen frame for screen printing according to claim 1, wherein the arc-shaped screen frame for sideways printing is provided in a seesaw-like arc shape by means of guides of the bottom surface arc shape of the front and rear frame wood. 4. Two rollers are placed on the upper surface of the front and rear frame at intervals, and the rollers are provided so as to reciprocate in parallel with the printing surface together with the squeegee, and two squeegee tips are always provided. The arc-shaped screen frame for screen printing according to claim 1, which is provided at the apex of an isosceles triangle formed by the center points of the rollers and the three points of the squeegee tip. 5. Two squeegees, left and right, are set parallel to each other at the lower end of the squeegee holder, and the squeegee holder is rotated about the pivot point by the constant angle, so that the left and right squeegees are located at respective center points of the two rollers. The arc surface screen frame for screen printing according to claim 1, which is provided so as to be switched to a vertex position of an isosceles triangle to be formed. 6. A squeegee block equipped with two rollers and a squeegee holder is provided, and the squeegee block is
The two rollers are placed on the upper surface of the front and rear parallel frame of the arc-shaped screen frame, and are reciprocally movable in parallel to the printing surface with the squeegee tip in contact with the screen. A circular screen screen frame for screen printing. 7. The arc surface screen frame for screen printing according to claim 1, wherein the squeegee block is provided so as to be separated from the arc surface screen frame and detached or moved upward or sideways.