JP3084844B2 - Screen printing apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for printing a viscous fluid, such as an adhesive or creamy solder, on an object to be printed such as a printed circuit board, and more particularly to a screen printing apparatus for improving control accuracy of printing conditions.

[0002]

2. Description of the Related Art A cream solder printing apparatus generally has the following configuration. Hereinafter, the configuration of the printing squeegee will be described with reference to FIGS. 4 and 5.
In FIG. 4, after the printed board 1 is positioned and fixed by the stage section 2, the printed board 1 rises to just below the screen plate 5 fixed to the screen frame 4 by the cylinder 3. Thereafter, the squeegee 6 descends and the print head 7 moves to print the cream solder 8 on the printed circuit board 1. Then, the stage unit 2 moves down and printing is completed. In FIG. 5, reference numeral 9 denotes a print head frame of a screen printing machine,
An air cylinder 10 for moving the squeegee 6 up and down is attached. A base plate 11 is fixed to the tip of the air cylinder 10, and a block 12 is attached to the base plate 11. Further, a swing block 14 is fitted so as to be swingable about a pin 13 fixed to the block 12 as a fulcrum. A swing plate 15 is provided on the upper surface of the swing block 14, and a compression spring 16 is held between the swing plate 15 and the base plate 11. At a position opposite to the compression spring 16 with the pin 13 being substantially at the center, a micrometer head 17 whose tip is freely adjustable so that the tip abuts on the swing plate 15 is attached to the base plate 11. Reference numeral 18 denotes a squeegee holder for holding the squeegee 6 therebetween. Reference numeral 19 denotes a guide shaft for moving the squeegee 6 up and down.
1 and slidably fitted to the head frame 9. Reference numeral 20 denotes a double nut screwed into a piston rod 21 of the air cylinder 10, which adjusts a gap between the double nut and the cylinder end 22 by the amount of tightening to adjust the amount of vertical movement of the squeegee 6. When adjusting the parallelism of the squeegee 6 with respect to the screen surface of the screen printing machine, the clamp lever 23 adjusts the amount of protrusion of the tip of the micrometer head 17 with the pin 13 as a fulcrum, thereby moving the swing block 14 via the base plate 11. After adjusting to a desired angle, the swing block 14 is fixed by tightening the clamp lever 23.

[0003]

However, in the above configuration, when the squeegee 6 is pressed against the screen 5 in order to adjust the distance between the squeegee 6 and the screen 5 or the degree of parallelism thereof, the squeegee 6 and the screen 5 are adjusted. Is measured visually or using a workout gauge, and there is much room for individual differences among the measurers. Further, when the squeegee 6 is pressed against the screen 5, the amount of vertical movement of the squeegee 6 cannot be determined quantitatively due to deformation of the squeegee 6 itself. Further, the printing condition is not the adjustment of the pressing force of the squeegee 6 against the screen 5 but the adjustment of the squeegee 6 on the screen 5 by the amount of vertical movement stroke. There is a problem in that setting and adjustment of printing conditions, not adjustment, requires experience and intuition.

SUMMARY OF THE INVENTION In view of the above problems, the present invention automatically adjusts the squeegee swing and vertical movement stroke, and
An object of the present invention is to provide a device capable of adjusting a squeegee by capturing a pressing force of the squeegee against a screen as a printing condition.

In order to solve the above-mentioned problems, the present invention is directed to claim 1, wherein a stage for positioning an object directly below the screen, a squeegee is moved up and down on the screen, and the squeegee is parallel to the screen. A print head that can be swung so as to become, and a screen printing apparatus that prints a viscous fluid on the object by moving the screen over a screen after a squeegee is brought into contact with the screen by a descending operation of the print head. , The lifting of the squeegee comprises a motor, a ball screw that can be raised and lowered by rotation of the motor, and a lifting guide, and the squeegee swings around the center of the squeegee as a fulcrum. The squeegee is operated by a motor and a ball screw that can be moved up and down by rotation of the motor. Ball screw and provided the pressure sensor between said squeegee, based on a measurement result of the pressure sensor,
It is an object of the present invention to provide a screen printing apparatus that can move the squeegee up and down or swing. According to a second aspect of the present invention, in the printing method of the screen printing apparatus according to the first aspect, a step of inputting respective pressing forces against the screen at both ends of the squeegee, and pressing each of the both ends of the squeegee input in the step. Calculating the average value of the force, lowering the squeegee on the screen, obtaining the average value of the values of the respective pressure sensors at both ends of the squeegee, until the average value matches the average value obtained in the step. The step of lowering the squeegee and the step of operating both ends of the squeegee with a motor and a ball screw that can be raised and lowered by rotation of the motor so that both ends of the squeegee have the input pressing force. It is an object of the present invention to provide a screen printing method.

The measurement of the pressing force of the pressed printing squeegee and the change of the printing condition for changing the pressing force of the printing squeegee can be performed either automatically or manually.

[0007]

According to the present invention, the printing squeegee is automatically pressed against the printing screen, the pressing force of the pressed printing squeegee is measured, and the printing squeegee is measured based on the measurement result of the measuring means. Since the pressing force of the squeegee is changed, there is no room for individual differences among the measurers to adjust the distance between the squeegee and the screen or the parallelism thereof. Further, when the squeegee is pressed against the screen, the amount of vertical movement of the squeegee is quantitatively determined. Further, the printing condition is a direct adjustment of the printing condition of adjusting the pressing force of the squeegee against the screen, which facilitates setting and adjustment of the printing condition.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A screen printing apparatus according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall view of a screen printing apparatus according to an embodiment of the present invention. In FIG. 1, 9
Is a print head frame of a screen printing machine. The squeegee 6 is moved up and down, and a ball screw 31 is rotated by a pressing means for automatically pressing the screen, for example, a stepping motor 30, and the bracket 32 is moved to move the lot 33 up and down. Let it. The base plate 11 is fixed to the tip of the lot 33, and the block 12 is attached to the base plate 11. Further block 12
A swing block 14 is fitted so as to be swingable with the pin 13 fixed to the fulcrum as a fulcrum. A swing plate 15 is provided on the upper surface of the swing block 14.

Means for changing the pressing force of the printing squeegee, for example, the ball screw 35 is rotated by the stepping motor 34 to move the bracket 36 so that the tip of the base plate 11 contacts the swinging plate 15. The head 37 whose tip can be freely adjusted is moved up and down. Measuring means for measuring the pressing force of the pressed printing squeegee, for example, a pressure sensor 38 is provided on the upper surface of the oscillating plate 15 with which the head tip contacts.

Reference numeral 18 denotes a squeegee holder for holding the squeegee 6 therebetween. Reference numeral 19 denotes a guide shaft for vertically moving the squeegee, one end of which is fixed to the base plate 11 and slidably fitted to the head frame 9. The degree of parallelism of the squeegee 6 to the screen surface of the screen printing machine is determined by the right and left heads 37 with the pin 13 as a fulcrum.
The base plate 1
The swing block 14 is adjusted to a desired angle via 1.

The screen printing apparatus configured as described above is controlled by a computer (not shown). The computer stores a program shown in the flowcharts of FIGS. 2 and 3, and the computer controls the vertical stroke of the squeegee and the pressing force of the squeegee on the screen according to the program. Hereinafter, FIGS. 2 and 3
The vertical stroke adjustment of the squeegee and the adjustment of the pressing force of the squeegee on the screen will be described with reference to the flowchart of FIG. When the squeegee adjustment program is started, initial settings are made in step S1 (hereinafter abbreviated as S1; the same applies to other steps). In step S2, the squeegee is parallelized to the screen surface.
At 3, the origin of the vertical stroke of the squeegee is extracted. If the origin extraction is completed, the determination result of S4 is YE
At S, the squeegee adjustment is performed in S5 and below. In S5, the vertical stroke of the squeegee is adjusted,
Alternatively, adjustment of the pressing force of the squeegee against the screen is selected.

When the vertical stroke adjustment of the squeegee is selected in S5, the vertical stroke from the origin of the vertical stroke of the left and right heads is input in S6. The left and right heads referred to here are both ends of the squeegee 6
Parts, that is, at the left and right positions of the squeegee 6,
A motor 34 and a boom which can be raised and lowered by rotation of the motor 34;
Of the left and right heads
Actuation raises and lowers both ends of the squeegee, that is,
Can move. When this input is completed and the input completion data is input, the determination result in S7 becomes YES and the process proceeds to S8 and subsequent steps. In S8, the average value of the vertical strokes of the left and right heads from the origin is calculated, and in S9, the lot 33 moves by the average of the vertical strokes calculated in S8. In S10, the average value of the vertical movement stroke amounts calculated in S8 is subtracted from the vertical movement stroke amounts of the left and right heads, and the left and right heads move up and down by the calculated amounts.

When the adjustment of the pressing force of the squeegee on the screen is selected in S5, the pressing force of the left and right heads on the screen is input in S12. When this input is completed and the input completion data is input, the determination result of S13 becomes YES and the process proceeds to S14 and thereafter. In S14, the average value of the pressing force of the left and right heads against the screen of the squeegee is obtained. In S15, the lot moves until the average value of the pressing force of the right and left heads against the screen becomes the average value of the pressing force obtained in S14. I do.

In S16, the left and right heads move so that the pressing force of the squeegee on the screen becomes the pressing force of the left and right heads on the screen input in S12. In S11, a determination is made as to whether or not resetting is required by the operator, and Y is input.
In the case of ES, the squeegee adjustment is completed, and the program ends.

As described above, according to the present embodiment, the squeegee 6 can be set to the vertical movement stroke arbitrarily set by the stepping motors 30 and 34, and the pressing force of the squeegee measured by the pressure sensor 38 is used. By feeding back to the vertical stroke amount of No. 6, the printing conditions can be set reliably.

In this embodiment, the squeegee adjustment is performed only at the beginning of printing. However, the adjustment may be performed for each printed board or for each fixed number of sheets. You may go. Also, the squeegee may be adjusted by determining the printing situation. Although not illustrated in many other ways, various modifications, elevating devices, etc., based on the knowledge of those skilled in the
The invention can be implemented in improved form.

[0018]

As described above, according to the present invention, the pressing force of the squeegee against the screen is measured, and if necessary, the vertical movement stroke of the squeegee is corrected based on the measurement result. Setting and adjustment can be facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a main part of a screen printing apparatus according to an embodiment of the present invention.

FIG. 2 is an overall flowchart of the same embodiment.

FIGS. 3A and 3B are partial flowcharts of the same embodiment.

FIG. 4 is a schematic front view of the present invention and a conventional screen printing apparatus.

FIG. 5 is a schematic front view of a main part of a conventional screen printing apparatus.

[Explanation of symbols]

Reference Signs List 6 squeegee 30 stepping motor 31 ball screw 32 bracket 33 lot 34 stepping motor (means for changing pressing force) 35 ball screw (means for changing pressing force) 36 bracket (means for changing pressing force) 37 head (means for pressing force) Means for changing) 38 Pressure sensor (means for measuring pressing force)

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Miyake 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (56) References JP-A-61-124191 (JP, A) JP-A-61-138545 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41F 15/40 B41F 15/08 H05K 3/12

Claims (2)

(57) [Claims] 1. A stage for positioning an object directly below a screen, and a squeegee is raised and lowered on the screen.
And, a print head capable of swinging the squeegee so as to be parallel to the screen, and after the squeegee is brought into contact with the screen by the lowering operation of the print head, the viscous fluid is moved by moving the screen on the screen. In a screen printing apparatus for printing on an object, the lifting and lowering of the squeegee includes a motor, a ball screw that can be raised and lowered by rotation of the motor, and a lifting guide, and the swinging of the squeegee takes a fulcrum around a central portion of the squeegee. And operating both ends of the squeegee with a motor and a ball screw that can move up and down by rotation of the motor.A pressure sensor is provided between the ball screw that swings the squeegee and the squeegee, A screen printing device capable of raising and lowering or swinging the squeegee based on a measurement result of a pressure sensor. 2. The printing method of a screen printing apparatus according to claim 1, wherein the pressing force of each end of the squeegee against the screen is input, and the pressing force of both ends of the squeegee input in the step is input. And lowering the squeegee on the screen to determine the average value of the pressure sensors at both ends of the squeegee, and until the average value matches the average value determined in the step. And actuating both ends of the squeegee with a motor and a ball screw that can be raised and lowered by rotation of the motor so that both ends of the squeegee have the input pressing force. Screen printing method.