JPH0145996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a board suction device for a printed circuit printing machine or the like.

BACKGROUND OF THE INVENTION Generally, in the production of printed wiring boards (hereinafter referred to as wiring boards), the printing process on wiring boards is carried out by suctioning the wiring boards onto a suction cup of a printing machine having a large number of air intake ports. However, for industrial wiring boards, double-sided printed wiring boards, etc., small holes for mounting circuit elements are made at the beginning of the manufacturing process, and screen printing is performed to fit the small holes. For this reason, if the intake port of the suction cup overlaps with the small hole of the board, the negative pressure inside the suction cup will decrease and the adsorption force of the board will be weakened. It is not possible to print stably. There was also the problem that the suction cup's top surface and interior became dirty due to the ink sucked in, making cleaning time-consuming.

As a countermeasure to these problems, we used a method in which small holes in the wiring board that coincided with the air intake ports were filled with filler in advance, and the filler was removed after printing. However, this method requires a lot of man-hours,
The board also has the problem of being prone to defects such as disconnections in the printed wiring, which is a cause of cost and quality problems.

Purpose: In view of the above-mentioned circumstances, the present invention provides a suction device for board materials such as wiring boards, which can obtain sufficient suction force even when the small holes of the substrate and the intake port overlap, and is free from the risk of ink suction. The purpose is to

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, a suction cup 1 of a printed wiring board printing apparatus has a hollow box-like structure as a whole, and three positioning claws 25 (see FIG. 1) are provided on the upper surface of the suction cup 1 at regular intervals. A large number of intake ports 2 are provided. As shown in FIG. 2, the interior of the suction cup 1 is divided by a partition plate 3 into a lower first intake chamber 4 and an upper second intake chamber 5. Suction cup 1
A first intake port 6 and a second intake port 7, which communicate with the first intake chamber 4 and the second intake chamber 5, respectively, are machined on one side wall of the housing. The first intake port 6 and the second intake port 7 are connected to a negative pressure drive source 27 by a single intake pipe 12 via a first on-off valve 10 and a second on-off valve 11, respectively.
It is connected to the.

Inside the suction cup 1, valve sleeves 13 are located at positions corresponding to the respective intake ports 2, passing through the partition plate 3 so that the upper and lower end surfaces thereof are in close contact with the top surface of the second intake chamber 5 and the bottom surface of the first intake chamber 4, respectively. installed. In addition, only one valve sleeve 13 is illustrated in the drawing. Inside the valve sleeve 13, a large-diameter guide hole 14 and a small-diameter relief hole 1 are arranged from the upper end surface.
5 is machined, and a stepped portion serving as a locking portion is formed at the boundary between both holes 14 and 15 due to the difference in diameter. Further, an escape hole 16 is machined from the opposite end surface, and a small guide hole 17 that is coaxial with the guide hole 14 is provided so as to penetrate through both the escape holes 15 and 16.
A relief hole 1 is provided on the lower side of the valve sleeve 13.
A first intake hole 18 of the valve sleeve communicating with the guide hole 14 is provided through the valve sleeve, and a second intake hole 19 of the valve sleeve communicating with the guide hole 14 is provided through the upper side.

This valve sleeve 13 has a cylindrical valve piston 20 with a bottom and a guide hole 14 and a small guide hole 1.
7 and is fitted so as to be slidable up and down. Inside the valve piston 20, a stepped hole 21 with a bottom is formed from the upper end surface. A spring 22 is provided between the stepped portion of the stepped hole 21 and the upper surface of the second intake chamber 5 to urge the valve piston 20 downward.
is inserted. Normally, a stepped portion serving as an outer engaging portion of the valve piston 20 comes into contact with a stepped portion between the guide hole 14 and the escape hole 15 of the valve sleeve 13, and is held at the intake stop position.
In this state, on the outer surface of the valve piston 20, at a height corresponding to the relief hole 16 and relief hole 15 of the valve sleeve 13, there is a valve piston second intake hole 24, which is the same as the valve piston first intake hole 23 as a communication hole. are installed through the top and bottom, respectively.

When the valve piston 20 is pushed down in the state shown in FIG. 21, valve piston first intake hole 23, relief hole 16 of valve sleeve 13, valve sleeve first
Intake hole 18, first intake chamber 4, first intake port 6, first
The on-off valve 10 and the intake pipe 12 constitute a part of the first intake passage. Further, when the valve piston 20 moves upward against the biasing force of the spring 22 (FIG. 4), the first intake hole 23 of the valve piston is closed by the small guide hole 17 of the valve sleeve 13, and the first intake hole 23 is closed by the small guide hole 17 of the valve sleeve 13. The passage closes. On the contrary, at this time,
The stepped hole 21 of the valve piston 20, the second intake hole 24 of the valve piston, the escape hole 15 and the guide hole 14 of the valve sleeve 13, the second intake hole 19 of the valve sleeve, the second intake chamber 5, the second intake port 7, the The second intake passage, which is composed of the second on-off valve 11 and the intake pipe 12, opens.

Now, when the wiring board 26 is placed on the suction cup 1 and the suction device is started, the negative pressure drive source 27 is activated, the first on-off valve 10 is opened, and the second on-off valve 1 is opened.
1 is closed. Therefore, first, the air in the first intake chamber 4 is exhausted.

In this case, if the intake port 2 is blocked by the wiring board 26 (FIG. 3), the guide hole 14 of the valve sleeve 13 and the stepped hole 20 of the valve piston 20
Internal negative pressure increases. Therefore, the valve piston 20 is instantaneously sucked upward, as shown in FIG. At this time, the first on-off valve 10 closes, and conversely, the second on-off valve 11 opens. Based on this, when the second intake passage opens, the second intake hole 19 of the valve sleeve and the second intake hole 24 of the valve piston face each other and are held in a position where intake is possible, so that the negative pressure inside the valve piston 20 further increases. Then, the wiring board 26 is attracted.

On the other hand, the small hole 28 provided in the wiring board 26
(FIG. 5), air flows in from this small hole 28 as the first on-off valve 10 is opened. Therefore, the valve piston 20 does not move upward, and the second intake passage remains closed (FIG. 5). Therefore, even if the first on-off valve 10 is closed and the second on-off valve 12 is opened, the first air intake chamber 4 remains at atmospheric pressure and the small hole 2 remains at atmospheric pressure even during printing.
Because of this, without air being sucked in from 8.
No ink is sucked in.

When printing is finished, the second on-off valve 11 is automatically closed. Therefore, the negative pressure in the second intake chamber 5 and the upper part of the valve piston 20 decreases, and the valve piston 20 returns downward due to the urging force of the spring 22.

As described above, only the intake ports 2 in the portions of the wiring board 26 where the small holes 28 do not overlap exhibit the suction action, and the intake ports 2 facing the small holes 28 do not perform the suction action.

Next, the second embodiment embodying this invention will be described in the sixth embodiment.
This will be explained based on FIGS. In this second embodiment, escape holes 15 and 16 are not provided, and a suction hole 31 is provided through the bottom plate of the first intake chamber 4 so as to face the small guide hole 17 of each valve sleeve 13. .

Now, when the intake port 2 is closed by the wiring board 26, when the first on-off valve 10 is opened and the air in the first intake chamber 4 is discharged, the valve sleeve intake hole 18 and the valve piston intake hole 23 are closed. The air inside the valve piston 20 is also discharged. In this case, the chamber between the bottom surface of the valve piston 20 and the bottom plate of the first intake chamber 4 is at atmospheric pressure through the suction hole 31, so the valve piston 20 rises. As shown in FIG. 7, when the valve piston 20 is raised, the valve sleeve intake hole 19
When the second on-off valve 11 is opened and the air in the second intake chamber 5 is discharged in this state, the valve piston 20 maintains the state shown in FIG. 7. Therefore, the intake port 2 attracts the wiring board 26.

In addition, as shown in FIG. 8, the air intake port 2 and the wiring board 26
When the small holes 28 of the first opening/closing valve 10 face each other,
As the valve piston 20 opens, air is sucked in through the small hole 28, so the valve piston 20 does not rise. Therefore, when the second on-off valve 11 is subsequently opened, the second intake hole 19 of the valve sleeve is closed, so the intake port 2 does not perform a suction action.

In this case, as in the first embodiment, since the first air intake chamber 4 is at atmospheric pressure, no ink is sucked in from the air intake port 2 while printing is being performed.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9 and 10. In this third embodiment, an intake hole 32 as a communication hole is provided only in the upper part of the small diameter part of the valve piston 20, The intake hole of the valve sleeve 13 is similar to that of the first embodiment.

In a normal state, the valve piston 20 is raised by the spring force of the spring 33, as shown in FIG.

Further, in this third embodiment, the first intake port 6 and the first on-off valve 10 are not provided. Note that the first intake chamber 4 communicates with the atmosphere.

Now, in this third embodiment, the second on-off valve 11
When the intake port 2 is opened, as shown in FIG.
When the small hole 28 of the wiring board 26 is opposed to the small hole 28 of the wiring board 26, a strong suction flow is generated from the small hole 28 to the valve sleeve intake hole 19. For this reason, valve sleeve 1
The space 34 between the inner peripheral surface of the valve 3 and the outer peripheral surface of the valve piston 20 becomes particularly negative pressure, and the valve piston 20 moves down against the spring force of the spring 33 as shown in FIG. Hold. Therefore,
The valve sleeve intake hole 19 is closed and the intake port 2
Intake from the air is stopped.

Further, when the intake port 2 is closed by the wiring board 26, no strong suction flow is generated, so that the valve piston 20 maintains the state shown in FIG. 9. For this reason, the inside of the valve piston 20 becomes below atmospheric pressure like the second intake chamber 5, and the intake port 2 attracts the wiring board.

Effects As described above, in this invention, ink is not sucked in at the location where the air intake port and the small hole of the substrate overlap, and the atmospheric pressure is maintained at the location where the air intake port overlaps with the small hole in the substrate, so that ink is sucked through the air intake port even while printing is being performed. This has the effect of preventing printing defects and soiling of the substrate.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a suction cup and a substrate positioned thereon, Fig. 2 is a vertical sectional view showing the first embodiment, and Figs. 3 to 5 similarly explain the operation of the first embodiment. Figure 3 is a partial cross-sectional view showing the state before air intake when the air intake port is blocked by a board, Figure 4 is a partial cross-sectional view showing the state after air intake, and Figure 5 is a partial cross-sectional view showing the state after air intake. The state before and after inhalation is shown when the mouth and the small hole of the substrate overlap. 6 to 8 are partial sectional views showing the second embodiment, and FIGS. 9 and 10 are partial sectional views showing the third embodiment. Suction cup…1, intake port…2, intake chamber…5, valve sleeve…13, intake hole…19, valve piston…20, communication hole…24, 32, negative pressure drive source…2
7.

Claims (1)

[Claims] 1. A suction cup 1 having a hollow interior and a plurality of suction ports 2 opened on a suction holding surface, and the suction cup 1.
In a suction device having a negative pressure drive source 27 connected to communicate with the inside of the suction cup 1, an intake chamber 5 which can be brought into negative pressure by the negative pressure drive source 27 is provided on the back side of the suction holding surface. A cylindrical valve sleeve 13 is provided in the intake chamber 5 in correspondence with the intake port 2 and is brought into close contact with the back surface of the suction holding surface, and the valve sleeve 13 is configured to communicate with the intake port 2. A valve piston 20 having an intake passage formed therein is fitted so as to be movable between two positions, an intake stop position and an intake possible position, and the valve sleeve 13 and the valve piston 20
is provided with a locking portion and an engaging portion for regulating the position of the valve piston 20 to the intake stop position, and furthermore, on the outer surface of the valve sleeve 13 and the outer surface of the valve piston 20 on the side opposite to the intake port 2 from the engaging portion of the valve piston 20,
The intake chamber is provided with an intake port 19 and communication holes 24 and 32, which cannot communicate with each other when the valve piston 20 is located at the intake stop position, and which can communicate with each other when the valve piston 20 is located at the intake possible position. The present invention is characterized in that a holding means is provided for holding the valve piston 20 at the intake stop position when the inside of the valve sleeve 13 is in communication with the outside through the intake port 2 while the inside of the valve sleeve 13 is under negative pressure. Board material suction device for printed wiring printing machines, etc.