JPH0512038Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a squeegee drive device in a screen printing machine.

(Prior Art) Generally, when a screen printing machine is used to print a printed wiring board with solder resist ink, the wiring pattern on the surface of the board becomes uneven. However, when the orientation of the squeegee is parallel to the linear pattern of the wiring pattern, ink often does not enter the recesses on the substrate surface. Therefore, it is necessary to run the squeegee so that the handle of the wiring pattern and the squeegee are not parallel to each other.

However, with current screen printing machines,
As shown in FIG. 3, the rotation of one motor 23 provided on the machine stand 22 of the printing press is transmitted to the squeegee tuning shaft 25 via the chain 24, and the rotation of this tuning shaft 25 is further transmitted to the chain 24. 26
The force is transmitted to the squeegee 21 via the squeegee 21 and converted into a horizontal reciprocating motion. That is, since the squeegee 21 is pulled and driven by the chain 26 with both ends thereof being in synchronization with each other, the squeegee 21 always travels while maintaining the same posture.

Therefore, in order to avoid the squeegee 21 from being parallel to the horizontal line pattern that frequently appears in the wiring pattern of the circuit board, in the conventional apparatus, the squeegee 21 is mounted obliquely as necessary. However, when the wiring pattern has a diagonal linear pattern, the squeegee 21 and the pattern may become parallel. Therefore, there is a problem that ink is not imprinted into the recessed portions of the substrate, and printing cannot be performed reliably.

(Problem that the invention attempts to solve) As mentioned above, this invention attempts to solve the problem that printing is not performed reliably even when printing a linear pattern that extends diagonally on a printed wiring board. The purpose is to provide a squeegee drive device for a screen printing machine that can reliably print on printed wiring boards.

Structure of the invention (means to solve the problem) In order to solve the above problems, this invention
A pair of motors for separately driving both ends of the squeegee and a plurality of sensors for detecting passage of both ends of the squeegee are provided on each squeegee running rail, and the rotational speed of the motor is changed based on the detection signal of the sensor. We adopted the method of letting

(Function) By adopting the above-described means, this invention can arbitrarily change the attitude of the running squeegee according to the directionality of the linear pattern.

(Example) Hereinafter, an example of this invention will be described in detail with reference to FIGS. 1 and 2.

A pair of squeegee running rails 2a, 2b are provided on both sides of a machine stand 1 of a screen printing machine, and motors 3a, 3b are attached to one ends of these running rails 2a, 2b, respectively. These motors 3
The output shafts 4a and 4b of a and 3b are respectively connected to both ends of a squeegee 5 disposed between the running rails 2a and 2b via chains 6a and 6b, and both ends of the squeegee 5 each have their own running speed independent of the others. It is now possible to run on it. In addition, each traveling rail 2a,
A plurality of sensors 7a, 8a are installed at any location of 2b.
and 7b, 8b are provided, and these sensors 7a,
8a, 7b, and 8b define the passage area of the squeegee 5 as 5.
It is divided into two parts.

As shown in FIG. 2, the sensors 7a, 8a and 7b, 8b are electrically connected to controllers 9a and 9b, respectively, and the controllers 9a, 9b drive the motors via motor drive circuits 10a, 10b, respectively. 3a and 3b.

Incidentally, although not shown, a printed wiring board having a large number of linear patterns and in which the direction of inclination of the linear patterns changes halfway is arranged on the machine stand of the printing press.
The back surface of the screen that has been pressurized by the squeegee 5 is pressed against the front surface of the wiring board.

Now, the operation of the squeegee drive device configured as described above will be explained below.

First, considering the printing start point on the wiring board and the linear pattern in the first area in the vicinity, this first
The attitude of the squeegee 5 is maintained so that it is not parallel to the linear pattern of the area. After this, both motors 3a,
3b is rotated at a constant speed to advance the squeegee 5 and move it from the first area to the second area.

In this second area, the linear pattern on the wiring board is different from the pattern in the first area. Therefore, it is necessary to change the attitude of the squeegee 5 to prevent the linear pattern and the squeegee 5 from becoming parallel. That is, when the squeegee 5 passes through the first area and reaches the second area, the sensor 7a of one running rail 2a
detects passage of one end of the squeegee 5 and outputs a passage signal to the control section 9a. Then, the control section 9a
outputs a high-speed drive signal based on the passing signal to the motor 3a via the motor drive circuit 10a to increase the rotational speed of the motor 3a. Therefore, as shown by the two-dot chain line, one end of the squeegee 5 leads, the other end follows, and the squeegee 5 advances obliquely between the two running rails 2a and 2b. Therefore, the squeegee 5 is prevented from being parallel to the linear pattern on the wiring board, and the ink is imprinted on the linear pattern.

When the squeegee 5 reaches the third area from the second area, the sensor 7b of the other running rail 2b detects this and outputs a passage signal to the control unit 9b. The control unit 9b outputs a high-speed drive signal based on this passing signal to the motor 3b via the other motor drive circuit 10b, thereby increasing the rotational speed of the motor 3b. Then, the other end of the squeegee 5 leads, one end follows, and the squeegee 5 moves forward in a diagonal shape different from the second region. Therefore, the squeegee 5 is prevented from being parallel to the linear pattern on the wiring board, and the ink is imprinted on the linear pattern.

Similarly, in the fourth region and the fifth region, the sensors 8a and 8b respectively detect the passing of the squeegee 5, and change the rotational speed of the motors 3a, 3b as appropriate to change the attitude of the squeegee 5. This prevents the line pattern of the wiring board from becoming parallel to the line pattern of the wiring board.

Effects of the invention As detailed above, this invention has one motor installed on each side of the machine base to drive both ends of the squeegee separately, and detects the passing of both ends of the squeegee to drive the motor. Since the rotational speed is changed appropriately, even if the inclination direction of the linear pattern changes midway, printing can be reliably performed on the printed wiring board, which is a desirable idea in practical terms.

[Brief explanation of drawings]

Figure 1 is a plan view embodying this invention, Figure 2 is a block diagram showing the control system of this invention, and Figure 3 is a diagram showing the control system of this invention.
The figure is a plan view showing a conventional technique. Motor...3a, 3b, squeegee...5.

Claims (1)

[Claims for Utility Model Registration] 1. A pair of motors 3a, 3b for separately driving both ends of the squeegee 5, and a plurality of sensors 7a, 8 for detecting passage of both ends of the squeegee 5.
a, 7b, 8b are provided on the squeegee running rails 2a, 2b, respectively, and the sensors 7a, 8a,
The motor 3 is activated by the detection signals 7b and 8b.
A squeegee drive device for a screen printing machine, characterized in that the rotational speeds of a and 3b are changed. 2 The sensors 7a, 8a, 7b, 8b detect the passage of both ends of the squeegee 5, output an electric signal, and operate the motors 3a, 3 based on this signal.
a control unit 9a for changing the rotational speed of b;
9b. The squeegee drive device for a screen printing machine according to claim 1, wherein the squeegee drive device is electrically connected to the respective terminals 9b.