JPH07102674B2 - Squeegee device for screen printing machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a squeegee device for a screen printing machine, and particularly a squeegee follows fine irregularities on the surface of a substrate when printing a fine electronic circuit. The present invention relates to a squeegee device for a screen printing machine, which enables printing with a uniform film thickness and prevents the occurrence of whiskers or blurring in printing.

[Conventional technology]

In the conventional device, as described in JP-A-53-61419, a squeegee is divided into a plurality of blocks, and only the above-mentioned blocks that cover the convex portion of the surface of the substrate escape and the other blocks. Was closely sliding on the screen. The squeegee is moved up and down by an air cylinder, a hydraulic cylinder, or an electric motor. An example of this type of device using a cam and a cross shaft gear is disclosed in Japanese Patent Laid-Open No. 57-201658.

[Problems to be Solved by the Invention]

In the prior art described above, when a fine electronic circuit is printed on a substrate, the escape of the tip of the squeegee against the irregularities of the substrate or the minute irregularities due to the printed circuit is due to the elastic deformation of the material forming the squeegee or the inside of the cylinder that raises and lowers the squeegee. This is done by lifting and lowering the piston with sliding resistance.
In any case, the pressing down pressure at the tip of the squeegee locally changes, does not follow the unevenness of the substrate, and the film pressure of the printed ink is not uniform. Further, the guide for raising and lowering the squeegee is attached to the squeegee holder, and when the squeegee rises and lowers, the guide also rises and lowers, so that the mass to be raised and lowered becomes large and the followability to the unevenness is further deteriorated. Furthermore, since the guide moves up and down, it is not possible to improve the guide accuracy of the guide, and it is impossible to improve the printing accuracy. Since the squeegee's ascent / descent speed is not controlled to obtain at least a low speed, when the squeegee rises, the pressing pressure of the squeegee suddenly disappears, causing the screen to vibrate due to the elasticity of the tension, causing ink to scatter. There is a problem in that unnecessary ink is attached due to contact between the screen and the screen and the printed substrate, and so-called whiskers and blurring occur.

An object of the present invention is to provide a squeegee device for a screen printing machine capable of obtaining a uniform printed film thickness by following the squeegee well with respect to minute irregularities on the substrate without changing the pressing pressure. Therefore, another object of the present invention is to provide a squeegee device for a screen printing machine, which can prevent unnecessary ink attachment, whiskers, and blurring.

[Means for Solving the Problems]

In order to achieve the above object, the first elevating means is a telescopic body that expands and contracts by supplying or discharging gas into the bellows-shaped cylindrical body, and the second elevating means includes a stepping motor and a ball screw. The block can be raised and lowered,
The elevating block is provided with a first elevating means, a squeegee holder is connected to the tip of the elastic body of the first elevating means with a spherical joint, and a guide for guiding the elevating block and the squeegee holder is fixed to the upper frame, The squeegee holder is guided by a linear cross roller guide provided on the guide, and the squeegee that has finished printing rises at a low speed until the squeegee leaves the surface of the screen. Is controlled by the control valve, or the stepping motor is driven at a low speed.

[Operation] Since the expansion / contraction body of the first elevating / lowering unit is formed of a bellows-shaped cylinder, it is expanded by supplying gas into the cylinder,
During printing, when the squeegee slides through the screen on the surface with unevenness of the substrate or minute unevenness due to the printed circuit, the bellows-shaped cylinder does not cause fluctuations in the pressure of the gas inside and the bellows-shaped Since the expansion and contraction of the squeegee can be expanded and contracted without any resistance, the squeegee follows the unevenness of the substrate with a uniform pressing pressure.

The squeegee holder that holds the squeegee has a structure in which it is guided by a linear cross roller guide provided on a holder guide fixed to a frame arranged at the top, so that the mass that moves up and down following the unevenness of the substrate Becomes smaller,
The sliding resistance associated with lifting and lowering is extremely small, and since it is guided from the frame, the squeegee holder can be guided accurately.

In the rising section until the squeegee that has finished printing leaves the surface of the screen, it is possible to discharge the internal gas of the expandable body of the first elevating means while controlling it with the control valve.
The squeegee rises at a low speed, preventing the screen from wobbling. Further, since the stepping motor is used to drive the second elevating means up and down, it is possible to easily drive at a low speed and prevent the occurrence of screen shake.

〔Example〕

An embodiment of the present invention will be described below. FIG. 1 is a front view of the squeegee device, in which a substrate 2 is placed at a predetermined position on the upper surface of the table 1.
Is detachably arranged by suction, and a screen 4 attached to the plate frame 3 with a predetermined tension is arranged with a distance A from the substrate 2. The tip 5a of the squeegee 5 is the screen 4
And a space B apart from each other. Squeegee mounting part 6
The squeegee 5 is fixed by a plurality of bolts 7, and the central portion is pivotally held by a squeegee holder 9 by a pin 8. Both ends 6a and 6b of the squeegee attaching portion 6 are adjusted and held by the adjusting bolts 10 provided on the side end portions 9a and 9b of the squeegee holder 9 so that the substrate 2 and the squeegee tip 5a are parallel to each other. A spherical joint 11 is fitted in the center of the squeegee holder 9, and the spherical joint 11 is screwed to the lower end portion 13a of the elastic body 13 of the first elevating means 12, and both side portions 9c and 9d of the squeegee holder 9 are straight crossed. It is guided by a holder guide 14 which is a roller guide. The upper end 13b of the telescopic body 13 is screwed and fixed to the lifting block 15, both sides 15a and 15b of the lifting block 15 are guided by the block guide 16, and the ball screw 17 is fitted to the center of the lifting block 15. The female screw 15c is fixed. The holder guide 14 and the block guide 16 are fixed to a guide plate 18, and the guide plate 18 has a frame 22 on which a pneumatic device 19 for supplying gas to the first elevating means 12 and a drive device 21 for the second elevating means 20 are arranged on the upper part. It is fixed with screws. The holder guide 14 and the block guide 16 may be integrated into a guide 14 '(see FIG. 3). The pneumatic device 19 includes a pneumatic part 19a, a control valve part 19b, an exhaust part 19c, and a pipe 19d.
Is connected to the upper end of the expandable body 13 via the flexible hose 19d 'and the elevating block 15. The drive device 21 of the second elevating means 20 comprises a stepping motor 23, a gear transmission 24 and a brake 28, and drives the ball screw 17.

FIG. 2 is a side view of the squeegee device, and the frame 22 is a rod.
A rail 27 is guided by a squeegee sliding cylinder 26 via 25 to move.

In printing, the gas is supplied at a predetermined atmospheric pressure by the air pressure device 19 to extend the telescopic body 13 by the dimension C, and then the stepping motor 23 is driven to lower the elevating block 15 by the ball screw 17. , The squeegee tip 5a lowers the screen 4 while lowering the dimension D in which the squeegee tip 5a comes into contact with the upper surface of the substrate 2 with a predetermined pressing pressure, and is stopped and held by the brake 28.
In this state, due to the elasticity of the expandable body 13, the dimension C becomes the dimension C'and the dimension D '(D' =
C ′ + D) to come in contact with the substrate 2 through the screen 4 and a predetermined pressing pressure is applied, and the squeegee sliding cylinder 26 extends to move the squeegee 5 in the direction of arrow E for printing. The tip 5a of the squeegee during printing follows the unevenness of the surface of the substrate 2 and repeats a slight ascending / descending operation, but since the expandable / contractible body 13 has a bellows-like shape during the ascending / descending operation, it does not slide in the case of a cylinder and a piston. There is no equivalent to dynamic resistance, expansion and contraction does not involve resistance, and there is no change in gas pressure, and therefore the pressing pressure of the squeegee tip 5a does not change.
Further, the elevating and lowering guide of the squeegee holder 9 is performed by the holder guide 14 which is a linear cross roller guide with extremely small sliding resistance, and the mass of the guide guide holder 14 is attached to the frame 22 so that the accuracy is high. The squeegee holder 9 that moves up and down can be reduced in mass, and the followability of the squeegee tip 5a to the irregularities of the substrate 2 can be improved and the pressing pressure can be equalized.

When the detector 29 detects that the squeegee tip 5a has slid on the screen 4 and has reached the printing end point at the position F, and stops the extension of the squeegee sliding cylinder 26, the control valve portion 19b becomes exhausted, The gas inside the telescopic body 13 is exhausted gently, the tip 5a of the squeegee rises in the section of dimension G, and then the exhaust part 19c is opened and the second elevating means 20 rapidly raises it. Since the tip 5a of the squeegee rises gently until it separates from the screen 4, the screen 4 does not shake due to the elasticity of the tension. The stepping motor 23 of the second elevating means 20 may be driven at a low speed to raise the section of the dimension G.

〔The invention's effect〕

According to the present invention, the squeegee that follows the irregularities on the substrate can be moved up and down with a small mass in the ascending / descending portion and an extremely small lifting resistance, and it is possible to perform it without fluctuations in the pressing pressure at the tip of the squeegee. The ink film thickness is uniform. Further, since the return of the screen after the printing is finished rises gently, the screen does not shake, and it is possible to prevent the occurrence of whiskers or blurring of the printed ink. Furthermore, since there is no change in the pressing pressure at the tip of the squeegee,
No impact occurs between the screen and the tip of the squeegee,
The life can be extended. As for the guide of the squeegee, it can be firmly fixed by fixing the guide to the upper frame, so that the accuracy is high, the occurrence of play during operation is small, and the accuracy can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a front view when the holder guide and the block guide of FIG. 1 are integrated. 1 ... table, 2 ... substrate, 3 ... plate frame, 4 ... screen, 5 ... squeegee, 8 ... pin, 9 ... squeegee holder, 11 ... spherical joint, 12 ... first lifting means ,13……
Telescopic body, 14 …… Holder guide, 15 …… Lifting block, 16
...... Block guide, 17 ...... Ball screw, 18 ...... Guide plate, 19 ...... Pneumatic device, 20 ...... Second lifting means, 21 ...... Drive device, 22 ...... Frame, 23 ...... Stepping motor, 24
...... Gear transmission, 25 …… Rod, 26 …… Squeegee sliding cylinder, 27 …… Rail, 28 …… Brake.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Kato, Naraumi Ceramics Co., Ltd., No. 3 Denjiyama, Narumi-cho, Midori-ku, Nagoya, Aichi Prefecture No. 3 of Mt. Harima within Narumi Ceramics Co., Ltd. (56) Reference JP-A-1-141739 (JP, A) JP 53-32429 (JP, B2) JP 50-29554 (JP, B2)

Claims (3)

[Claims] 1. A squeegee device of a screen printing machine for printing an electronic circuit on a substrate, a squeegee holder for holding a squeegee, a first elevating means for elevating the squeegee holder, and an elevating block for supporting the first elevating means. A second elevating means for elevating the elevating block, a holder guide for elevating the squeegee holder, and a block guide for elevating the elevating block. A squeegee device for a screen printing machine, which is composed of an elastic body that expands and contracts when supplied and exhausted. 2. The squeegee device for a screen printing machine according to claim 1, wherein the holder guide and the block guide each comprise a linear cross roller guide. 3. The squeegee device for a screen printing machine according to claim 1, wherein the second elevating means comprises a stepping motor.