JPH05193105A - Screen printing machine - Google Patents

Abstract

PURPOSE:To embody easy operation for bringing a squeegee into contact with a screen with an appropriate pressure by a method wherein a device for touching and separating the squeegee is composed of two air cylinders connected to two locations, distant from each other in the longitudinal direction of the squeegee, and control devices which control separately air pressures to be supplied to the air cylinders. CONSTITUTION:In the case where a first squeegee 112 is used in execution of printing, air is supplied to chambers in the upper parts of air cylinders 114 and 116 by operation of control by a control device while chambers in the lower parts are opened to the atmosphere, and thereby the first squeegee 112 is lowered and is brought into contact with a screen. As the weight of an ascending/descending part 117 of the first squeegee is offset by the force of a spring 170 in the course of lowering, the first squeegee member 154 comes into contact with the screen only by air pressure supplied to the cylinders 114 and 116. Since the structure is so constructed that the squeegee member 154 can be brought into contact with the screen with desired pressure regardless of the weight of the ascending/descending part 117, air pressure supplied to the cylinders 114 and 116 is controlled by the control device so that the squeegee member 154 can be brought into contact with the screen by the desired pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing machine, and more particularly to adjustment of contact pressure when a squeegee contacts a screen.

[0002]

2. Description of the Related Art A screen printer is a device for printing a printing agent at a predetermined position on a plate to be printed, such as a case where an adhesive or a cream solder is applied to an electronic component bonding position or a lead connecting position on a printed circuit board. And is known from Japanese Utility Model Laid-Open No. 1-63169. This screen printing machine
Generally, it comprises a printing plate support, a screen support, and a squeegee device. The squeegee device includes a squeegee, a squeegee moving device that moves the squeegee on a screen supported by a screen support, and a squeegee contacting / separating device that moves the squeegee toward and away from the screen. In the contacted state, the printing agent is moved on the screen supported by the screen support base by the squeegee moving device, so that the printing agent passes through the through holes formed in the screen and is supported on the plate support base to be printed. Printed on the printing plate. When a printing agent is printed on a printing plate by such a screen printing machine, the contact pressure with which the squeegee contacts the screen affects the quality of printing. If the contact pressure is insufficient, the printing agent may be excessively printed in a state of being raised from the opening of the through hole of the screen on the side where the squeegee moves, and the printing agents printed adjacent to each other may be connected to each other. If the contact pressure is excessively large, the squeegee scrapes off the printing agent that has entered the through hole, resulting in inconveniences such as a shortage of printing amount and a decrease in durability of the squeegee and the screen. Therefore, conventionally, the squeegee is brought into contact with and separated from the screen by an air cylinder, and the magnitude of the supply air pressure is controlled,
It is practiced to obtain a contact pressure of an appropriate magnitude.

[0003]

However, this conventional screen printer has a problem that it is difficult to obtain an appropriate contact pressure of the squeegee. Since the squeegee is pressed against the screen by a single air cylinder that is connected to the center of the pin so as to be rotatable relative to each other, it is difficult to obtain a proper contact pressure at both ends. For example, to get a precise and even contact pressure across the squeegee,
On the contrary, it is difficult to make the contact pressure at both ends different. In some cases, it may be necessary to intentionally vary the contact pressure depending on the distribution and size of the through holes formed in the screen, but conventionally it was not possible to meet this requirement. Further, when the squeegee is brought into contact with the screen, the weight of the squeegee is added to the screen, so it is possible to bring the squeegee into contact with the screen with a contact pressure larger than the contact pressure obtained by the weight of the squeegee, but The squeegee cannot be brought into contact with the screen with a contact pressure smaller than the contact pressure required, and therefore, it may not be possible to obtain an appropriate contact pressure. Further, the contact pressure is controlled by controlling the air pressure of the air cylinder, but since the contact pressure is determined by both the weight of the squeegee and the air pressure, the weight of the squeegee must always be considered when controlling the air pressure. However, it was difficult to control and it was difficult to obtain an appropriate contact pressure. It is an object of the inventions of claims 1 and 2 to provide a screen printing machine in which it is easier to bring the squeegee into contact with the screen with an appropriate contact pressure.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention of claim 1 provides a squeegee contacting / separating device of a screen printing machine comprising the plate support for printing, a screen support and a squeegee device. , (A) two air cylinders each having a piston connected to two locations separated in the longitudinal direction of the squeegee, and (b) a control device for individually controlling the air pressure supplied to the air cylinders. What is done is the gist. In order to solve the above-mentioned problems, the invention of claim 2 connects a squeegee contacting / separating device of a screen printing machine equipped with the printing plate support, the screen support and a squeegee device to (a) squeegee, A weight reducing device for reducing the weight of the squeegee, (a) at least one air cylinder in which a piston is connected to the squeegee, and (c) a control device for controlling the air pressure supplied to the air cylinder are included. That is the summary.

[0005]

In the screen printing machine according to the first aspect of the present invention, the squeegee is pressed against the screen by two air cylinders which are connected to each other at two positions separated in the longitudinal direction, and the air pressure supplied to the two air cylinders is high. The contact pressures at the both ends of the squeegee can be controlled arbitrarily because they are individually controlled. For example, the squeegee can be brought into contact with the screen with a uniform pressure, or the contact pressure at both ends can be intentionally made different. In the screen printing machine according to the invention of claim 2, the weight of the squeegee when the squeegee is brought into contact with the screen is reduced by the weight reducing device. The weight of the squeegee may be reduced in part or all, and the weight of the squeegee may not be added to the screen. In any case, by reducing the weight of the squeegee, it becomes easy to bring the squeegee into contact with the screen at an appropriate pressure by controlling the air pressure supplied to the air cylinder. When the total weight of the squeegee is reduced, the contact pressure is determined only by the supply air pressure regardless of the weight of the squeegee, so that it is not necessary to consider the weight of the squeegee when controlling the air pressure, and the control becomes easier. At the same time, an extremely small contact pressure can be realized. Further, even when a part of the pressure is reduced, the feasible range of the contact pressure is widened by the reduced amount, and the contact pressure can be easily controlled by controlling the air pressure because the influence of the weight is reduced.

[0006]

As described above, according to the invention of claim 1, the contact pressure of the squeegee with respect to the screen can be made uniform or can be intentionally made different, and the printing accuracy can be improved. .. According to the second aspect of the invention, the controllable range of the contact pressure of the squeegee on the screen is widened, and the control of the contact pressure is facilitated, so that the printing accuracy is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to a screen printing machine for a printed circuit board will be described in detail with reference to the drawings. The screen printing machine shown in FIGS. 6, 7 and 8 includes a board conveyor 12 that conveys a printed board 10 (see FIG. 7) as a printing plate, and a board positioning support device 1.
4, screen positioning support device 16, squeegee device 1
8, a solder recovery device 20 (see FIG. 6), a screen transfer device 22 shown in FIG. 8, a screen housing device 24, and a screen cleaning device 26.

The board conveyor 12 is, as shown in FIG.
It is provided with a pair of rails 32 and 34 provided on the base 30. A rope (not shown) is annularly arranged on each of the rails 32 and 34, and the printed circuit board 10 is transported by circulating the rope. The distance between the rails 32 and 34 is the printed circuit board 1
It can be adjusted according to the size of 0. Further, the substrate positioning and supporting device 14 includes a substrate supporting base 38 as a printing plate supporting base. The board supporting base 38 is moved up and down by an elevating device (not shown). The board supporting table 38 is conveyed by the board conveyor 12, stopped by a stopper (not shown) and positioned by a positioning pin (not shown) by the vacuum. It is adsorbed and lifted from the substrate conveyor 12 and brought into contact with the screen.

The screen positioning and supporting device 16, the squeegee device 18, and the solder recovery device 20 are supported by a pair of frames 40 and 42 mounted on a base 30 so as to be able to move up and down. As shown in FIGS. 6 and 8, four columns 44 are erected on the base 30, and levers 46 and 47 are attached to each column 44 by a shaft 48 so as to be rotatable about a horizontal axis. As shown in FIG. 8, one of the frames 40 is attached to a pair of levers 46 that are separated from each other in the printed circuit board conveying direction (left and right direction in the drawing) so as to be rotatable about a horizontal axis, and the other frame 40 is attached. The frame 42 is attached to the remaining pair of levers 47 so as to be rotatable around a horizontal axis.

A pair of levers 46 supporting the frame 40
As shown in FIGS. 6 and 8, an arm 54 extends at a right angle from between a portion where the frame 40 is connected and a shaft 48, and each tip of the arm 54 is extended by a rod 56. It is connected. Further, the other end of one lever 46 of the pair of levers 46 is attached to the rotary plate 6 by a rod 58 arranged in the vertical direction.
It is rotatably connected to 0. The rotating plate 60 is a gear 6 that is rotated by a lifting motor 62 (see FIG. 8).
It is fixed to a shaft 68 of a gear 66 meshed with the gear 4. Similarly, as shown in FIG. 8, arms 70 are fixed to the other pair of levers 47 that support the frame 42 and are also connected by rods 72, and one lever 47 has a rod 74 extending in the vertical direction. The rotary plate 75 is rotatably connected to the lower end of the rod and is fixed to the shaft 68. Therefore, when the shaft 68 is rotated by the lifting motor 62, the rotating plates 60 and 75 are rotated, and the four levers 46 and 47 are simultaneously rotated 90 degrees as shown by the two-dot chain line in FIG. The screen positioning support device 1 is rotated.
6, the squeegee device 18 and the solder recovery device 20 are located right above the substrate support 38 as shown by the solid lines in FIGS. 6 and 7, and the descending end position for screen printing and the two-dot chain line are shown. , Higher than the descending end position and moved to the ascending end position that has moved to the downstream side in the printed circuit board transport direction. The devices 16, 18, and 20 are two sets of parallelogram link devices composed of a base 30 on which four columns 44 are erected, levers 46 and 47 and frames 40 and 42, and one lever 46 and 47. Arms 54, 70, rods 56, 72 for transmitting the rotation of the lever to the other levers 46, 47, and a lifting motor 62, gears 64, 6
6 and the rod 58, 74 and the like are lifted and lowered by an elevating device composed of a driving device.

The screen positioning support device 16 is provided below the frames 40 and 42. As shown in FIGS. 6 and 7, a total of four brackets 76 are fixed to the lower surfaces of the frames 40 and 42, and a screen support base 78 is attached to the brackets 76 and fixed to the screen 80 and its periphery. And a screen frame 82 which has a screen. Screen 80
As shown in FIG. 5, through holes 83 opening on both front and back surfaces are formed at positions corresponding to the printing positions of the printed circuit board 10.
And printed on the printed circuit board 10. The screen support base 78 is a rectangular frame, on which the screen frame 8
2 is placed, and the X axis direction parallel to the printed circuit board transport direction and the Y axis direction position orthogonal to the X axis direction in the horizontal plane are positioned by the X axis direction positioning device and the Y axis direction positioning device, respectively. At the same time, it is fixed to the screen support base 78 by a fixing device.

Next, the squeegee device 18 will be described with reference to FIGS. The squeegee device 18 has a slide 84 as shown in FIG. Guide blocks 86 and 87 are fixed to both side surfaces of the slide 84,
Guide rails 88 and 90 fixed to the frames 40 and 42 are movably fitted therein. Slide 84
A nut 92 is fixed to the screw shaft 94, and both ends thereof are screwed into a screw shaft 94 supported by the one frame 42. The screw shaft 94 is moved by the servo motor 96 for moving the squeegee.
The slide 84 is moved in the X-axis direction by being rotated by (see FIG. 11). In the present embodiment, the slide 84, the nut 92, the screw shaft 94, the squeegee moving servo motor 96, etc. constitute a squeegee moving device.

A frame 100 is fixed on the slide 84. As shown in FIGS. 1 and 2, the frame 100 includes a pair of side walls 102, a top wall 104, and a back wall 106.
And slides 84 and frame 100
First squeegee unit 108 and second squeegee unit 110 are provided. These units 108,
The configuration of 110 is the same, and the first squeegee unit 10
8 will be described in detail.

The first squeegee unit 108 has a first squeegee 112 and is moved up and down by a pair of first squeegee lifting air cylinders 114 and 116 (see FIG. 2) so that the first squeegee 112 approaches the screen 80. It is provided with a first squeegee elevating part 117 which is separated. These air cylinders 114 and 116 are fixed downward on the ceiling wall 104 and at a distance in the Y-axis direction, and their piston rods 118 and 120 (see FIG. 2) are mounted on the ceiling wall 1.
The rods 122 and 124 (see FIG. 1) inserted through the shaft No. 04 and fixed to the lower ends thereof are fitted to the pair of guide tubes 126 and 128 erected on the slide 84 so as to be slidable in the axial direction. And the squeegee holder 1 at the lower end
30 is rotatably connected.

As shown in FIG. 3, the squeegee holder 130 has a square bar 132, brackets 134 and 136 fixed to both ends of the square bar 132 in the longitudinal direction, and a support having both ends fixed to the brackets 134 and 136. Member 1
38 has a fixed mounting plate 140. As shown in FIG. 3, elongated holes 142 and 144 are formed at two positions spaced apart in the longitudinal direction of the square bar 132, respectively.
The lower ends of 22, and 124 are respectively fitted,
Pins 146 and 148 parallel to the moving direction of the slide 84 are rotatably connected to the square bar 132. Rod 1
The inner diameters of the pin holes 150 and 152 into which the pins 146 and 148 of the rods 22 and 124 are fitted are slightly large, and the squeegee holder 130 can rotate a small angle in a vertical plane including the rods 122 and 124. ..

Further, the first squeegee 112 is mounted on the mounting plate 140 as shown in FIG. The first squeegee 112 has a long plate shape, and a first squeegee member 154 made of rubber is held by a squeegee holder 156. The lower end of the first squeegee member 154 is inclined and held in a direction away from the second squeegee unit 110. The first squeegee 112 is the squeegee holder 15
6 is fixed to the mounting plate 140 and rotates together with the squeegee holder 130 in a vertical plane. 1 in FIG.
Reference numerals 58 are shield plates attached to both ends of the squeegee holder 156 in the longitudinal direction, respectively, to prevent the creamy solder from protruding during printing. When the size of the printed circuit board 10 changes, the first squeegee 112 is attached to and detached from the squeegee holder 130, and the first squeegee member 154 is attached.
Are exchanged with those having a length corresponding to the dimensions of the printed circuit board 10.

As shown in FIG. 1, a rectangular hole 160 is formed in the square bar 132 at the center in the longitudinal direction thereof, and a lower end portion of an elevating rod 162 is fitted into the rectangular bar 132 and a pin 164.
Is rotatably connected to the square bar 132. The lifting rod 162 has a through hole 165 formed in the slide 84.
Through the spring 84, and is urged upward by a spring 170 arranged between a spring bearing 166 attached to the projecting end and a spring bearing 168 fixed to the lower surface of the slide 84. Accordingly, the first squeegee 112, the squeegee holder 130, the piston rods 118 and 120, the rod 1
22, 124, lifting rod 162 and spring receiver 166
And the like, and the lifting air cylinders 114, 116.
The weight of the first squeegee elevating / lowering unit 117 that is moved up and down by the is reduced. The spring 170 constitutes the weight reducing device. In the present embodiment, the spring load of the spring 170 is such that when the first squeegee 112 just descends until it comes into contact with the screen 80, its weight is reduced to 0 and no weight is added to the screen 80. Therefore, the first squeegee member 15
When the pressure of the air supplied to the upper air chambers of the air cylinders 114 and 116 is 0, the nozzle No. 4 contacts the screen 80 with a force of 0, and the contact force increases as the pressure of the air increases. During non-printing, the upper chambers of the air cylinders 114 and 116 are released to the atmosphere, while air is supplied to the lower chamber, and the first squeegee 112 is raised to the rising end position and separated from the screen 80. .. In addition, the spring receiver 16
A dog 172 is attached to the upper part of the squeegee 6, and the lower end of the first squeegee member 112 has a lower end sensor 174.
To be detected by.

The second squeegee unit 110 has the same structure, and the second squeegee lifting portion 178 is lifted and lowered by a pair of second squeegee lifting air cylinders 180 (only one of which is shown in FIG. 3). The rod 184 is connected to the lower end of the piston rod 182 of the second squeegee lifting air cylinder 180, and the rod 184
Squeegee holder 1 rotatably attached to the lower end of the
A second squeegee 188 is attached to 86. The second squeegee 188 is formed by holding a long plate-shaped rubber second squeegee member 190 by a squeegee holder 192, and the second squeegee member 190 has its lower end inclined in a direction away from the first squeegee member 154. Has been retained. Further, the lifting rod connected to the square member of the squeegee holder 186 is urged upward by a spring, and these second squeegee 188 and squeegee holder 18 are
6, the piston rod 182, the rod 184, and an elevating rod (not shown) and the like constitute a second squeegee elevating part 178, and the weight of the second squeegee elevating part 178 is reduced by a spring. The spring load of this spring is set such that the weight applied to the screen 80 when the second squeegee 188 just touches the screen 80 becomes zero, and the first air pressure is controlled by the air pressure supplied to the air cylinder 180. The contact pressure of the squeegee member 190 to the screen 80 can be adjusted. Further, the descending end of the second squeegee member 188 is detected by the dog 194 and the second squeegee descending end sensor 196.

The first squeegee 112 and the second squeegee 188 are used alternatively. The screen printing is performed by moving the squeegee from one side of the printed board 10 to the other side, and the squeegee located on the upstream side in the moving direction is used for printing. When two sets of squeegees are provided, reciprocal printing can be performed by selectively using the squeegee depending on the printing direction.

Next, the solder recovery device 20 will be described. As shown in FIG. 3, a pair of guide rails 200 (only one of which is shown in the drawing) extending in the vertical direction are provided on the back wall 106 of the frame 100 at a distance in the Y-axis direction. 202 is a guide block 204, 20
It is fitted so that it can move up and down. This lift plate 20
2, a plate 207 is fixed in a direction in which the plate 207 extends upward, and a piston rod 210 of an air cylinder 208 for raising and lowering the scooping member provided on the ceiling wall 104 is connected by a bracket 211. The elevating plate 202 is moved up and down by the expansion and contraction of.

The lower end of the elevating plate 202 is defined by a bolt 212 screwed on the lower surface of the elevating plate 202 abutting a stopper bolt 214 fixed to the slide 84. A mechanical valve 216 is attached to the side wall 102 of the frame 100 as shown in FIG. 1, and the lift plate 2 is adjusted by adjusting the amount of air supplied to the air cylinder 208.
The ascending / descending speed of 02 is switched between high and low stages. As shown in FIG. 4, a switching plate 218 is fixed to the elevating plate 202, and when elevating, the first switching surface 220 protruding toward the mechanical valve 216 side and the second switching surface 222 retracted from the mechanical valve 216 side are mechanical valve sequentially. 216 of the switching lever 224 in contact with the switching lever 2
24, and the switching lever 224 moves the first switching surface 2
The amount of air supplied to the air cylinder 208 is reduced and the ascending / descending speed is lowered in the state of being in contact with 20, while the amount of air supply is being increased and the ascending / descending rate is increased in the state of being in contact with the second switching surface 222.

From both ends of the lower end of the elevating plate 202 in the width direction, as shown in FIGS.
Is extended forward. Each of these support plates 232 has a substantially L-shape, is fitted into a notch 236 formed in the slide 84, and an arm portion 234 extending in the vertical direction faces a side surface of the squeegee holder 130 of the first squeegee unit 108. Has been made. A scooping device 237 is rotatably attached to these support plates 232. The scooping device 237 includes a pair of L-shaped brackets 238, a mounting plate 242 mounted on one of the L-shaped arm portions 240 of the brackets 238, and a scooping device fixed to the tip of the mounting plate 242. It has a member 244, is fitted in an elongated hole 248 (see FIG. 1) formed in the support plate 232 in the other arm portion 246 of the bracket 238, and is rotatably attached by a pin 250.

The arm portion 240 is formed with a notch 252 opening to the lower surface and the tip end surface, and the mounting plate 242 is fitted into the notch 252 at one end thereof and
It is rotatably supported by a pin 253 about an axis parallel to the Y-axis direction. The mounting plate 242 is used for the arm portion 2
The other end is biased toward the screen 80 by a spring 256 arranged between the plate 254 fixed to the lower surface of 40. 258 is a bolt that regulates the urging force of the spring 256. The scooping member 244 is longer than the first squeegee member 154 and
And a pair of side walls 262 at both ends are located on both sides of the first squeegee member 154 in the longitudinal direction, as indicated by a chain double-dashed line in FIG. Scooping member 244
Are exchanged according to the size of the first squeegee member 154, and the side walls 262 are always long enough to sandwich the first squeegee member 154 from both sides in the longitudinal direction. The bottom wall of the scooping member 244 is curved along an arc centered on the axial center of the pin 250, and the upper surface thereof is a scooping surface 266 having a partially cylindrical surface. A knife edge 268 is formed at the tip of the scooping member 244.

The pair of brackets 238 are connected by a horizontally arranged rod 270, and the piston rod 274 of the scooping member rotating air cylinder 272 is connected to the joint member 276 at the longitudinal center of the rod 270. It is rotatably connected by. The air cylinder 272 is rotatably connected to the plate 207 attached to the elevating plate 202 by a pin 280, and the bracket 2 is expanded and contracted by expanding and contracting the piston rod 274.
38 is rotated and the scooping member 244 is moved along the screen 80.

As shown in FIG. 1, pins 284 are movably fitted to the lower ends of the arm portions 234 of the support plate 232 in the Y-axis direction, and are moved by a pin driving cylinder 286. ing. At the upper end portions of the brackets 134 and 136 of the squeegee holder 130, the first squeegee 112 descends to the lower end, and the fitting holes that are substantially concentric with the pin 284 when the elevating plate 202 descends to the lower end. 288 is formed, and the lift plate 202 and the first squeegee 112 are connected by fitting the pin 284 into the fitting hole 288.

Screen 8 used for screen printing
0 is replaced with another screen 80 when necessary, such as when a predetermined number of prints are made or when the type of the printed circuit board 10 is changed. The screen transport device 22 is
The screen 80 is conveyed between the screen positioning and supporting device 16 and the screen accommodating device 24 to automatically replace the screen. However, the screen conveying device 22 and the screen accommodating device 24 are disclosed in Japanese Patent Laid-Open No.
It is the same as the device described in Japanese Patent No. 317768, and will be briefly described.

As shown in FIGS. 6 and 7, the screen transfer device 22 has an X-axis slide 29 that moves in the X-axis direction.
0 and a Y-axis slide 292 provided on the X-axis slide 290 and moving in the Y-axis direction. Each of the X-axis slide 290 and the Y-axis slide 292 is provided with an engaging member that engages with the screen frame 82, and pulls out the screen frame 82 from the screen support base 78 and conveys it to the screen housing device 24. The screen accommodating device 24 has upper and lower two-stage screen accommodating portions that can be moved up and down by an elevating device, and the screen accommodating portions are selectively positioned at the screen transfer position and removed from the screen support base 78. 80 is accommodated and provides a new screen 80, which is the screen transport device 22.
Then, it is conveyed to the screen support base 78, and positioned and fixed. In addition, the screen storage device 24 may transfer the screen 80 by raising and lowering a stocker capable of storing 10 screens 80 vertically by an elevator.

Next, the screen cleaning device 26 will be described. As shown in FIGS. 7 and 8, the screen cleaning device 26 is located at a position adjacent to the screen housing device 24 of the frame 300 fixed on the base 30, above the screen transport device 22, and at the rising end position. It is provided at a height corresponding to the moved screen 80. The screen cleaning device 26, as shown in FIG.
When the ball screw 301 is rotated by the X-axis drive motor 302, the X-axis slide 306 is guided by the guide rail 304 and moved in the X-axis direction, and the ball screw 307 is provided on the X-axis slide 306.
Is rotated by the Y-axis drive motor 308, and is guided by the guide rail 310 to be moved in the Y-axis direction.

A long air ejector 316 and a solder suction device 318 are provided on the Y-axis slide 312 so as to be rotatable around an axis parallel to the X-axis direction. The bracket 320 is fixed on the Y-axis slide 312,
U-shaped brackets 324 and 326 are fixed to the upper and lower surfaces of the support member 323 fixed between the pair of side plates 322 of the bracket 320. A main body 328 of the air injector 316 has a tubular shape with a quadrangular cross section, and is fixed to a bracket 330 fixed to the upper surface of the main body 328 by a shaft 332 so as to be rotatable about an axis parallel to the X-axis direction. Has been. The body 334 of the solder suction device 318 also has a tubular shape with a quadrangular cross section, and a bracket 336 fixed to the lower surface thereof is attached to the upper bracket 324 by a shaft 338 so as to be rotatable about an axis parallel to the X-axis direction. Has been.

A supporting plate 340 is fixed to the supporting member 323, and an injector rotating air cylinder 342 and an aspirator rotating air cylinder 344 are attached downward and upward, respectively, and each piston rod 346, 3 is attached.
48 is a bracket 350, 352 fixed to the rear end of the main body 328, 334 (the end opposite to the screen 80 side).
Is rotatably connected to. Therefore, the expansion and contraction of the piston rods 346 and 348 cause the air ejector 316 and the solder suction device 318 to rotate in opposite directions, so that their tip portions (the end portions on the screen 80 side) approach and separate from each other. It will be. The rotation of the air ejector 316 and the tip of the solder suction device 318 toward each other is defined by a stopper (not shown).

A cylindrical casing 358 is fixed to the upper surface of the tip of the main body 328 of the air injector 316.
An air injection nozzle 360 is arranged upward in the casing 358. The air injection nozzle 360 is provided on the cylindrical connecting portion 362 and the upper end of the connecting portion 362.
The injection unit 364 has a thin box-shaped injection unit 364 having a width substantially equal to the width of the casing 358. The injection unit 364 has a large number of air injection ports formed on the upper surface thereof in a row in the X-axis direction. There is. The air injection nozzle 360 is disposed inside the main body 328, and has one end connected to the connecting portion 362 by a pipe 366.
Tube 3 connected to tube 366 at the rear end of body 328
68 is connected to a compressed air supply source 370,
The air supplied from the compressed air supply source 370 is jetted right above from the air jet nozzle 360.

Also within the casing 358 is a brush 374 adjacent to the air injection nozzle 360 by a shaft 376.
It is rotatably mounted around an axis parallel to the axial direction. The shaft 376 has a brush drive motor 378 (see FIG. 10).
The rotation of the pulleys 380 and 382 and the belt 38.
4, which causes the brush 374 to rotate.

Further, the space inside the main body 328 is connected to the vacuum source 398 via a hose 388, a joint member 390, a hose 392, a solder collection box 394 and a hose 396 connected to the rear end portion. Solder collection box 39
The space in 4 is divided by the partition plate 400 into two chambers 402,
It is divided into 404 and one chamber 402 has a main body 328.
, And the vacuum source 398 is connected to the other chamber 404. These chambers 402 and 404 are connected at the lower part, and the vacuum is supplied to the main body 328 through this part, while the filter 40 is provided at the upper part of the chamber 404.
6 is provided to prevent the creamy solder sucked by the vacuum from being sucked into the vacuum source 398 as described later. The solder collection box 39
The lower part of 4 is a detachable receiving box 408 so that the creamy solder that has been sucked and accumulated can be discarded.

A cylindrical contact member 410 is fixed to the lower surface of the tip of the main body 334 of the solder suction device 318. A tubular cushioning member 412 is fitted to the contact member 410 so as to be relatively movable in the axial direction and incapable of slipping out. The space inside the main body 334 also has a hose 414, the joint member 390, a hose 392, a solder collection box 394, and a hose 39.
6 to a vacuum source 398.

This screen printing machine is controlled by the control device 420 shown in FIG. The control device 420 is mainly composed of a computer, and is configured to lift and lower the squeegee device 18 and the like, the lifting motor 62, and the squeegee device 18.
Squeegee moving servo motor 96, first squeegee lifting air cylinders 114, 116, second squeegee lifting air cylinder 180, scooping member lifting air cylinder 208, scooping member rotating air cylinder 272, screen cleaning X-axis drive motor 30 of device 26
2, a Y-axis drive motor 308, an injector rotating air cylinder 342, a suction device rotating air cylinder 344, a compressed air supply source 370, a vacuum source 398, a substrate conveyor 12, a substrate positioning and supporting device (not shown). 14, the screen transport device 22, and the screen housing device 24 are connected. These are controlled according to a program stored in the ROM of the computer, and the conveyance, positioning, screen printing, replacement of the screen 80, cleaning, recovery of cream solder, etc. of the printed circuit board 10 are performed.

Next, the operation will be described. When creamy solder is printed on the printed circuit board 10 in the screen printing machine configured as described above, the screen positioning support device 16, the squeegee device 18, and the solder recovery device 20.
Is at the lower end position, the screen 80 is positioned and fixed on the screen support base 78, and the creamy solder having a proper viscosity is placed thereon. Further, in the squeegee device 18, the slide 84 is located at one end in the X-axis direction in the print area of the screen 80, and the first and second squeegees 112 and 188 and the scooping member 244 are provided.
Both are in the rising end position. And the printed circuit board 1
0 is conveyed by the substrate conveyor 12 and the substrate support 3
If the squeegee which is used for printing among the first and second squeegees 112 and 188 is lowered and brought into contact with the screen 80, the slide 84 is moved. Then, the creamy solder is printed on the printed circuit board 10.

If the first squeegee 112 is used for printing, the air cylinder 1 is controlled by the controller 420.
Air is supplied to the upper chambers of 14 and 116 and the lower chamber is released to the atmosphere, and the first squeegee 112 is lowered and brought into contact with the screen 80. At this time, as described above, the weight of the first squeegee lifting portion 117 is just canceled by the spring 170, so that the first squeegee member 154 is attached to the air cylinder 11.
Screen 80 with only the air pressure supplied to 4,116
Be contacted with. The first squeegee member 154 can be brought into contact with the screen 80 at a desired pressure regardless of the weight of the first squeegee lifting portion 117, and the pressure of the air supplied to the air cylinders 114 and 116 is controlled by the controller 420. Thereby, the size is controlled such that the first squeegee member 154 can be brought into contact with the screen 80 with a desired pressure. By providing a pressure gauge between the air cylinders 114 and 116 and the air supply source, it is possible to know the magnitude of the air pressure supplied to the air cylinders 114 and 116, and further the contact pressure to the screen 80. ..

Further, the first squeegee members 154 have two air cylinders 1 at positions separated in the longitudinal direction.
Since the screens 80 and 14 are brought into contact with each other, the contact pressure can be adjusted arbitrarily. For example, even if the printed circuit board 10 and the screen 80 are tilted, the first squeegee member 154 rotates around the pin 164 and follows them, so that the first squeegee member 154 contacts the screen 80 with a uniform pressure. It is also possible to intentionally make the contact pressure at both ends different. Thereby, for example, the through hole 8 formed in the screen 80
When the diameter of 3 is extremely small and it is difficult for the creamy solder to enter, the creamy solder is reliably printed by increasing the contact pressure of the portion of the first squeegee member 154 that moves on the through hole 83. It is possible to obtain effects such as being able to.

Note that it is not essential that the entire weight of the first squeegee elevating / lowering portion 117 is applied to the screen 80, and a part thereof may be applied. If it is necessary to increase the contact pressure, the weight of the first squeegee lift 117 can be applied to the screen 80 to reduce the supply air pressure.

In this way, when the slide 84 is moved and the cream solder is printed on one printed circuit board 10, the first squeegee 112 is raised, and after the printed circuit board 10 is ejected, a new print is performed. When the printed circuit board 10 is brought into contact with the screen 80, the second squeegee member 190 is brought into contact with the screen 80 and printing is performed. At this time, the weight of the second squeegee lifting portion 117 is not added to the screen 80, and the second squeegee member 190 is brought into contact with the screen 80 only by the air pressure supplied to the second squeegee lifting air cylinder 180.
This is the same as the case of the first squeegee member 154.

The screen 80 is replaced when a predetermined number of prints are made or the type of the printed circuit board 10 is changed. If the creamy solder remains on the replaced screen 80, the screen 80 is replaced. It solidifies on top and causes dirt and clogging, and such creamy solder cannot be reused, resulting in waste. Therefore, at the time of screen replacement, the creamy solder remaining on the screen 80 is first recovered by the solder recovery device 20.

At the end of printing, the cream solder is at one end in the squeegee movement direction in the print area of the screen 80, and the first squeegee 112 and the scooping member 244 are above the cream solder. The first and second squeegees 112 and 188 are both in the rising end position,
The scooping member 244 is also at the rising end position. From that state, after the first squeegee 112 is lowered as shown by the solid line in FIG. 3 and the scooping member 244 is lowered as shown by the chain double-dashed line, the first squeegee member 154 moves to the right by a small distance. Then, the first squeegee member 154 is brought into contact with the cream solder. Subsequently, the pin 284 is fitted into the fitting hole 288 and the first squeegee 1
After the 12 and the scooping member 244 are integrally connected, the scooping member 244 is rotated clockwise in FIG. 3 and moves toward the first squeegee 112 while pushing the creamy solder on the screen 80. To do.

The scooping member 244 is a spring 256.
Urges the tip end downward so that the tip end contacts the screen 80 before rotating until it approaches the first squeegee member 154, and the knife edge 268 is pressed against the screen 80. It will be in a state of being. Therefore, when the scooping member 244 is further rotated, the knife edge 268 moves along the screen 80 and moves to the first squeegee member 154 side while scraping the creamy solder, as shown by the solid line. When the knife edge 268 is close to the first squeegee member 154, the knife edge 268 enters between the creamy solder stopped by the first squeegee member 154 and the screen 80 to scoop up the creamy solder onto the rake face 266. Considering the first squeegee member 154, its surface facing the second squeegee member 190 will scrape the creamy solder onto the scooping surface 266 and cause the scooping member 244 to scoop it. In the scooping member 244, the knife edge 268 has the first squeegee member 15
4, the rubber squeegee member 154 is not damaged by the knife edge 268 because it is only rotated to a position separated by a small distance with respect to No. 4 and cannot be brought into contact with the first squeegee member 154. ..

After the scooping, with the two chambers of the first squeegee raising and lowering air cylinders 114 and 116 both open to the atmosphere, the slide plate 84 is moved up a small distance left in FIG. It is moved at a low speed. When the elevating plate 202 descends to the lower end, the second switching surface 222 of the switching plate 218 switches the lever 224 of the mechanical valve 216, and the elevating plate 202 moves up and down at a low speed. Therefore, the scooping member 244 and the first squeegee 11 connected by the pin 284.
2, the scooping member 244 rises while scraping the cream-like solder on the screen 80 while being slowly and diagonally moved upward. Scooping member 2
Although there is a gap between the first squeegee member 154 and the squeegee member 154, the cream-like solder is viscous,
44 and the first squeegee member 154 are moved obliquely upward at a low speed, so that the creamy solder in the gap between the scooping member 268 and the first squeegee member 154 is scooped from the screen 80, and , Not leaking between them.

If the first squeegee member 154 and the scooping member 244 are moved up and moved by a small distance, the movement is stopped and the speed is raised to the rising end position. In this state, the first squeegee member 154 and the scooping member 244 are separated from the screen 80, and the recovery of the creamy solder is completed, so that the creamy solder is quickly returned to the rising end position. After the creamy solder has been scooped from the screen 80 in this manner, the screen 80 is cleaned by the screen cleaning device 26 as described later. After cleaning, the screen 80 is replaced by the screen transport device 22.
The new screen 80 is conveyed and is accommodated in the screen accommodating device 24 and is positioned and fixed on the screen support base 78.

After fixing a new screen 80, the collected cream solder is returned onto the screen 80.
In this case, first, the solder recovery device 20 causes the screen 8
The first squeegee 112 and the scooping member 24 are moved to one end in the squeegee moving direction in the print area of 0.
4 is lowered and brought into contact with the screen 80.
In this case, the second switching surface 222 of the switching plate 218 switches the lever 224 of the mechanical valve 216 at the beginning of lowering of the elevating plate 202 to lower it at a high speed, but after descending for a certain distance, the first switching surface 220 causes the lever 224 to move. The screen 80 is changed over and is lowered at a low speed, so that the screen 80 is slowly brought into contact with the screen 80 without damaging the screen 80.

After descending, the pin 284 is disengaged from the fitting hole 288 and the first squeegee 112 and the scooping member 24 are removed.
The connection with 4 is released. Then, after the first squeegee 112 is raised, the second squeegee 188 is lowered and brought into contact with the rake face 266, as shown by the chain double-dashed line in FIG. Is rotated in the counterclockwise direction to cause the creamy solder on the rake face 266 to move to the second squeegee member 190.
It is scraped onto the screen 80 by. The cream-like solder is scraped down by the surface of the second squeegee member 190 on the side facing the first squeegee member 154, and then the second squeegee 188 and the scooping member 2 are provided.
The screens 44 are moved up to the ascending end positions and the screen printing is started.

When screen printing is first performed by the second squeegee 188, it is not necessary to raise the second squeegee 188, and screen printing is started as it is. This can be achieved by returning the creamy solder to the side where printing is started by the second squeegee 188.

As described above, the creamy solder remaining on the screen 80 is automatically recovered by the solder recovery device 20 and automatically returned to the screen 80, so that the worker performs recovery and return work. Compared with the case, the work is performed more quickly, and the collected creamy solder is used for the next screen printing, so that the waste of the creamy solder can be eliminated and other members such as the screen housing device can be installed. It doesn't get dirty. Furthermore, the cream-like solder that remains on the screen 80 and hardens is almost eliminated, and the screen 80 can be easily cleaned.

As described above, in the screen 80 used for printing, as the number of times of printing increases, creamy solder remains on the inner peripheral surface of the hole, or the back surface (printed circuit board 10).
Is attached to the printed circuit board 10).
May pollute. Therefore, when a predetermined number of sheets are printed, when it is determined that the through holes 83 are clogged by detecting the print result, when the screen 80 is replaced, when the work is temporarily interrupted, etc. At the time, the screen cleaning device 26 cleans the screen 80.

The screen cleaning device 26 is in the retracted position separated from the screen 80 as shown in FIG. 7 when not cleaning. When cleaning the screen, the screen 80 is moved to the rising end position. And the screen cleaning device 2
6, the tip end portions of the air ejector 316 and the solder suction device 318 are separated from each other as shown in FIG.
6 is located below the screen 80, and the solder suction device 318
Are moved in the X-axis direction and the Y-axis direction while being positioned above, and their tip ends are moved to the position of the screen 80 to be cleaned. After moving, as shown in FIG.
The tips are brought close to each other to sandwich the screen 80 from the upper and lower sides. At this time, the rotation of the air ejector 316 and the solder suction device 318 is restricted by a stopper (not shown), and at the tip of the solder suction device 318, the contact member 410 and the cushioning member 412 move relatively,
It is avoided that the air ejector 316 and the solder suction device 318 pinch the screen 80 with excessive pressure. In this state, compressed air is supplied to the air injection nozzle 360 and is sprayed at a right angle to the screen 80, so that the through hole 83
The creamy solder attached to the inner peripheral surface of the solder is blown up and removed.
8 is sucked into the solder collecting box 394 and stored in the receiving box 408. Further, the brush 374 is rotated at the same time as the blowing of the compressed air to remove the creamy solder attached to the back surface of the screen 80, and the removed creamy solder is sucked by the vacuum in the main body 328 of the air ejector 316. Collect in the receiving box 408.

When the screen 80 is partially cleaned, the air ejector 316 and the solder suction device 318 are moved to a narrow area including the cleaning position, and the area is moved in the X-axis direction and the Y-axis direction. And cleaning is performed. Since only the necessary portion can be cleaned, the air suction amount and the compressed air supply amount are small, and the device can be made compact and lightweight. Further, when there is time, the entire surface of the screen 80 may be cleaned, and in that case, the air ejector 316 and the solder suction device 318 are reciprocated in the Y-axis direction for cleaning. After each movement in one direction in the Y-axis direction, the respective tip portions of the air ejector 316 and the solder suction device 318 are separated from the screen 80, and after moving a distance slightly shorter than the width of the air ejection nozzle 360 in the X-axis direction. The screen 80 is brought into contact with the screen 80 for cleaning. After the cleaning is completed, the air ejector 316 and the solder suction device 318 are opened and retracted, and the screen 80 is returned to the lower end position. The creamy solder accumulated in the solder collection box 394 is discarded by removing the receiving box 408.

When cleaning the screen 80,
A solvent may be sprayed prior to removing the cream solder with the brush 374.

As is apparent from the above description, in this embodiment, the first squeegee lifting air cylinder 114,
116, air cylinder 180 for raising and lowering the second squeegee, spring 170 constituting the weight reducing device, and control device 4
20 constitutes a squeegee contacting / separating device.

The screen printing machine according to the present invention can be used more effectively if combined with the printing result detecting device described in the specification of Japanese Patent Application No. 233,882 / 1993 applied to the present applicant. .. To detect the print result, and based on the detection result, to bring the squeegee into contact with the screen so that an appropriate amount of printing agent is printed in an appropriate state,
The air pressure supplied to the air cylinder is controlled.

When the squeegee is brought into contact with the screen, it is not essential to reduce the weight of the first and second squeegee lifting portions 117 and 178, and the spring 170 is omitted and two air cylinders 114 and 116 are provided. It is also possible to individually control the supply air pressure to and 180. For example, the screen 80 of the first squeegee member 154
When the contact pressure to the first squeegee lifting unit 117 is higher than the pressure due to the weight of the first squeegee lifting unit 117, there is no problem even if the weight of the first squeegee lifting unit 117 is added. It can be obtained by controlling the supply air pressure to the. Also in this case, if the supply air pressures to the two air cylinders 114 and 116 are made equal, the first squeegee member 154 can be brought into contact with the screen 80 with a uniform pressure, and the supply air pressures can be made different. The first squeegee member 154 can be brought into contact with the screen 80 at partially different pressures. When the weight of the first squeegee lift 117 is different in the longitudinal direction of the first squeegee member 154, the contact pressure can be made uniform by making the supply air pressures to the air cylinders 114 and 116 different.

Further, in the above embodiment, the first and second squeegee raising / lowering portions 117 and 178 were respectively moved up and down by two air cylinders. However, the number of air cylinders is one as in the conventional case, and the weight reducing device is used. Even if the weight is only reduced by the above, the contact pressure can be controlled more easily than in the past, and the printing accuracy can be improved.

Further, in the above-described embodiment, the creamy solder is collected when the screen is replaced. However, when the printing is stopped for a long time, the creamy solder should be collected and returned to the solder container. As a result, the creamy solder is not left in the air for a long time, the creamy solder is not wasted, and the yield can be improved.

Further, in each of the above-mentioned embodiments, when the first squeegee member 154 and the scooping member 244 are brought close to each other at the time of collecting the creamy solder, a gap is left at the tip end thereof. May be touched, or moved until slightly crossed, to scrape the creamy solder.

Further, in the above embodiment, the two squeegee members 154 and 190 are used for collecting and returning the creamy solder respectively, but one squeegee member is used for collecting and returning. Good. The squeegee member and the scooping member are allowed to move relative to each other in the X-axis direction, so that the squeegee member is located in front of the turning direction of the scooping member during recovery, and the squeegee member contacts the scooping surface during returning. To do so. In this way, the creamy solder can be recovered and returned even in a screen printing machine having only one squeegee member.

Furthermore, in the above-mentioned embodiment, the squeegee member 244 is used for the squeegee member 154, 190.
The creamy solder was collected and returned by moving the squeegee member 15.
You may make it collect | recover and return by moving 4,190, or moving both.

Further, in the above embodiment, the screen 80
The upper creamy solder was sandwiched by the first squeegee 112 and the scooping member 244 from both the left and right sides to be scooped, but even if it is scooped by only one scooping member. Good. In this case, in the above embodiment, only the scooping member 244 is lowered and rotated to scoop out the creamy solder. At this time, the scooping member 24
Rotate 4 at a certain speed or more and scoop up using the inertia of the cream solder. By doing so, the number of members used for scooping can be reduced, and the recovery device can be configured easily and inexpensively.

Further, although the solder recovery device 20 is provided together with the squeegee device 18 in the above embodiment, it may be provided separately from the squeegee device 18. When the solder is collected, it is moved onto the screen 80 to collect the solder,
By doing so, the squeegee device 18 becomes lighter in weight, and its moving speed can be increased to improve the printing speed.

Although the screen cleaning device 26 is supposed to clean the spot-shaped portion of the screen 80, it cleans the strip-shaped portion of the screen 80 parallel to the X-axis direction (or the Y-axis direction). While moving in the Y-axis direction (or X-axis direction), the entire surface of the screen 80 may be cleaned at once.

Besides, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is an enlarged front view (partial cross section) of a squeegee device of a screen printing machine according to an embodiment of the present invention.

FIG. 2 is a front view showing the squeegee device.

FIG. 3 is a side view (partial cross section) showing the squeegee device together with a solder recovery device.

FIG. 4 is a front view showing an apparatus for switching the ascending / descending speed of the scooping member in the solder recovery apparatus.

FIG. 5 is a front sectional view showing a part of a screen of the screen printing machine.

FIG. 6 is a front view of the screen printing machine.

FIG. 7 is a side view of the screen printing machine.

FIG. 8 is a plan view of the screen printing machine.

FIG. 9 is a front view showing a screen cleaning device provided in the screen printing machine.

FIG. 10 is a plan view of the screen cleaning device.

FIG. 11 is a view showing a part of a control device for controlling the screen printing machine, which is deeply related to the present invention.

[Explanation of symbols]

 10 Printed Circuit Board 18 Squeegee Device 38 Board Support 78 Screen Support 80 Screen 84 Slide 92 Nut 94 Screw Shaft 96 Squeegee Moving Servo Motor 108 First Squeegee Unit 110 Second Squeegee Unit 112 First Squeegee 114, 116 First Squeegee Lifting Air Cylinder 117 First Squeegee Lifting Section 180 Second Squeegee Lifting Air Cylinder 170 Spring 178 Second Squeegee Lifting Section 188 Second Squeegee 420 Control Device

Front page continuation (72) Inventor Takashi Iwatsuki 19 Chasuyama, Yamamachi, Chiryu-shi, Aichi Fuji Machinery Manufacturing Co., Ltd. Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A printing plate support, a screen support, a squeegee, a squeegee moving device for moving the squeegee on a screen supported by the screen support, and a squeegee contacting / separating device for moving the squeegee toward and away from the screen. And a squeegee device including a squeegee, and the squeegee moves on a screen supported by a screen support table, so that a printing agent such as an adhesive or cream solder is attached to the printing plate supported by the printing plate supporting table. In a screen printing machine for printing, the squeegee contacting / separating device is provided with two air cylinders each of which pistons are connected to two places separated in the longitudinal direction of the squeegee, and supply air pressure to the air cylinders. A screen printing machine characterized by including a control device for controlling individually. 2. A printing plate support, a screen support, a squeegee, a squeegee moving device for moving the squeegee on a screen supported by the screen support, and a squeegee contacting / separating device for moving the squeegee toward and away from the screen. And a squeegee device including a squeegee, and the squeegee moves on a screen supported by a screen support table, so that a printing agent such as an adhesive or cream solder is attached to the printing plate supported by the printing plate supporting table. A screen printing machine for printing the squeegee contacting / separating device, a weight reducing device connected to the squeegee to reduce the weight of the squeegee, at least one air cylinder having a piston connected to the squeegee, and the air A screen printing device including a control device for controlling the air pressure supplied to the cylinder. Machine.