JPH09262964A - Screen process printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely remove a stringing resin generated in the ascent of a squeegee in a short time and thereby shorten a signals cycle time in a screen process printing device for applying resin to an electronic part. SOLUTION: A stringing resin 11 is positively removed instead of being allowed to drop naturally by providing scrubbers 1a, 1b which wipe off the stringing resin 11 generated when squeegees 6a, 6b are separated from a screen 3. In addition, sensors 2a, 2b for checking the presence of the stringing resin 11 should be provided depending upon necessity, so that no resin sticks to an area where the resin does not have to be applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing apparatus for applying a resin to an electronic component through a screen mask and printing the resin.

[0002]

2. Description of the Related Art FIGS. 3 (a) to 3 (d) are views showing an operational sequence in an example of a conventional screen printing apparatus. Conventionally,
This type of screen printing apparatus is, for example, as shown in FIG. 3A, a screen having a feed table 7 on which the electronic component 10 is placed, moved and positioned, and an opening having the same through hole pattern as the resin coating pattern. A squeegee head 5 including a mask portion 9 for holding the frame 3 by a frame, a resin supply nozzle 4 for dropping the resin on the screen 3, and squeegees 6a, 6b for stretching the dropped resin 8 on the screen 3.
a and 5b.

In this screen printing apparatus, in order to apply the resin to the outer shell of the electric component, first, as shown in FIG. 3 (a), the electronic component 10 sent to the feed table 7 is a predetermined portion under the screen 3. The resin supply nozzle 4 drops an appropriate amount of resin 8 onto the screen 3. Next, as shown in FIG. 3B, the screen 3 of the mask portion 9 is lightly pressed against the electronic component 10 placed on the feed table 7. Then, the squeegee head 5a is lowered and the squeegee 6a is pressed against the screen 3 to move in the direction of the arrow, and the resin 8 is stretched over the screen 3 as shown in FIG. As a result, the resin 8 is extruded from the opening hole of the screen 3 and applied to the electronic component element 10 to form a resin pattern. And the squeegee head 5a
And the printing operation is completed.

At this time, the resin 8 on the screen 3 adheres to the squeegee 6a, and as the squeegee 6a rises, the resin is stretched as if the string were pulled to form the thread-pulling resin 11. This state is usually called a threading phenomenon. However, the threading resin 11 should not drop due to the movement of the squeegee to other places where the resin should not be attached.
When the squeegee 5b is raised, as shown in FIG. 3D, for example, the operation of the squeegee 6a is stopped and maintained for several tens of seconds to drop the resin by its own weight and return it to the resin 8.

[0005]

In the conventional screen printing apparatus described above, since the stringing resin is removed by holding the operation of the squeegee for 10 to 20 seconds after the squeegee is raised, one processing cycle time is increased. There is a problem that it becomes long and the processing capability of the device is low. Japanese Patent Laid-Open No. 58-60595 discloses a screen printing device that removes such stringing resin more quickly. The stringing part is raised and held for a certain period of time to remove the stringing in an earlier time. However, this stringing removal method is still waiting for the resin to be naturally cut by its own weight, and the sequence operation is temporarily stopped due to the difference in time. As a result, it cannot be denied that one processing cycle time is accordingly long and the processing capacity is low.

Further, since the phenomenon of spontaneous cutting is utilized, the time during which the resin string is cut varies depending on the viscosity of the resin. Since there is no means for confirming whether or not it has run out even if it is controlled by the waiting time, the sequence operation progresses, and the squeegee operates in a stringing state, and there is a problem that the resin is applied to a portion that should not be applied.

Accordingly, it is an object of the present invention to provide a screen printing apparatus capable of reliably and rapidly removing the stringing resin and shortening one processing cycle time.

[0008]

The features of the present invention are a mask portion having a screen having opening holes having the same through hole pattern as the resin coating pattern, and a resin supply nozzle for dropping an appropriate amount of resin on the screen. A screen printing device comprising a squeegee head having a squeegee that stretches the dropped resin into the screen shape and pushes the resin into the opening hole to apply the resin to the electronic component, and raises the squeegee after applying the resin. The screen printing apparatus includes a scriber that wipes the resin string that is generated when the stringer is moved.

Further, it is desirable to include a sensor for detecting the presence or absence of stringing of the resin. Further, it is desirable that the scriber is provided with a soft rubber member having unevenness on the surface.

[0010]

Next, the present invention will be described with reference to the drawings.

FIGS. 1A to 1E are views showing the order of operation of the screen printing apparatus according to the embodiment of the present invention. As shown in FIG. 1A, this screen printing apparatus is provided with scribers 1a and 1b for scraping off the stringing resin 11 attached to the squeegee 6a. Otherwise, it is the same as the conventional example. Further, it is desirable to provide sensors 2a and 2b for confirming whether the stringing resin 11 has been completely removed.

The scribers 1a and 1b are linear members which extend in the direction perpendicular to the paper surface and are arranged so as to straddle the screen 3, and can come into contact with the squeegees 6a and 6b and scrape the stringing resin 11. As such, it is desirable to be made of elastic nylon or silicone material. Further, both ends of the scribers 1a and 1b are fixedly held by support members, and are constantly held by a tension mechanism (not shown) by tension without slack. Further, a sensor (not shown) that detects breakage and extension of the scribers 1a and 1b is provided between the support members (not shown).

A sensor 2 for confirming the presence or absence of the stringing resin 11.
Each of a and 2b is composed of a light emitting element and a light receiving element that are fixed to the main body base across the screen 3, and it is determined whether or not the light emitted by the light emitting element is blocked by the stringing resin 11. Further, in order to make the index faster, there is no problem even if the sequence operation can be performed without using this determination circuit.

Next, the conventional printing operation of this screen will be described. First, as shown in FIG. 1A, the squeegee 6a
The operation applies the resin to the electronic component 10, the squeegee head 5a rises, the resin adheres to the squeegee 6a, and the stringing resin 11 is formed. Next, the scribers 1a and 1b move to the right side of the paper surface, and as shown in FIGS. 1 (a) and 1 (b),
The scriber 1a comes into contact with the squeegee 6a and the squeegee 6a
Of the squeegee 1 by moving the scriber 1a
The thread cutting resin 11 of a is scraped off and stopped when the scriber 1a overruns the squeegee 6a. As a result, as shown in FIG. 1B, the resin of the squeegee 6a of the squeegee head 5a that has risen completely is completely removed.

Next, as shown in FIG. 1 (c), the squeegee head 5b descends and the squeegee 6b is lightly pressed against the screen 3. Then, when the squeegee heads 5a and 5b start moving in the direction of the arrow, the circuit including the sensors 2a and 2b is activated, and the movement of the squeegee heads 5a and 5b causes the sensor 2a to operate, so that the squeegee 5a receives the thread drawing resin 11 Determine the presence or absence. If not, the squeegee head 5a,
The moving operation of 5b is continued, the resin 8 is stretched on the screen 3 by the squeegee 6b, and the resin is started to be applied to the newly sent electronic component 10. If it is determined that the stringing resin 11 is present, an alarm is issued and the squeegee heads 5a and 5b are stopped.

Next, as shown in FIG. 1D, when the squeegee heads 5a and 5b reach a predetermined position and the resin application to the electronic component 10 is completed, the squeegee head 5b starts to move up. As a result, the resin is attached to the squeegee 6b and the stringing resin 11 is generated. At the same time, the scriber 1a,
1b moves to the right with respect to the paper surface and contacts the squeegee 6b. On the other hand, the feed table 7 positions the new electronic component 10 at a predetermined position under the screen 3.

Next, as shown in FIGS. 1 (d) to 1 (e), the scribers 1a and 1b are moved to the left side and the squeegee 6 is moved.
Scrap off the stringing resin attached to b. Then, when the squeegee head 5b is fully raised, the scribers 1a, 1
b moves to the right with respect to the paper surface and returns to the original position. Sensor 2
The determination circuit including b is activated to determine the presence or absence of the stringing resin. If not, the sequence operation proceeds and a proper amount of resin is dripped onto the screen 3 from the resin supply nozzle 4. In this way, the resin is continuously and automatically applied to the electronic components 10 that are sequentially sent, and the application process for all the electronic components stored in the stocker is completed.

As described above, by moving the squeegees 1a and 1b against the squeegees 6a and 6b to scrape off the resin adhering to the squeegees 6a and 6b, the stringing resin 11 can be reliably removed in a short time. Since it can be removed, the index time of the apparatus (one cycle time excluding the coating time) is shortened to about 1/3 of the conventional one, and the processing capacity can be improved. In addition, the occurrence of the problem of drooping of the stringing resin during the movement of the squeegee during the non-printing operation has been eliminated.

FIG. 2 is a diagram showing a modification of the scriber of FIG. As shown in FIG. 2, this scriber has a rubber shoe 1c attached to a base 1d, which is different from the conventional linear scriber. The rubber shoe 1c is preferably made of a soft sponge-like urethane rubber which has irregularities on the surface and bubbles inside.

When the soft rubber shoe 1c having the uneven surface is used, the squeegee 6 as shown by the chain double-dashed line
It is possible to transfer the resin that adheres due to the unevenness of the concave surface, following the steps a and 6b. In addition, this scriber has the advantages that it does not have the risk of being cut as described above, has excellent durability, and requires less frequent replacement. Further, there is an advantage that the stoppage of the device for replacement is eliminated and the processing capacity is further improved.

[0021]

As described above, according to the present invention, by providing a scriber for wiping off the stringing resin generated when the squeegee is separated from the screen, the sequence operation is stopped as in the conventional case. There is no need to wait until it falls, and one cycle processing can be performed in a shorter time, which has the effect of improving the processing capacity. Further, by providing a sensor for confirming the presence or absence of the thread-cutting resin, if necessary, the resin is not attached to the places where the thread cutting resin should not be applied, and there is an effect that the conventional problems do not occur.

[Brief description of drawings]

FIG. 1 is a diagram showing an operation sequence of a screen printing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a modification of the scriber of FIG.

FIG. 3 is a diagram showing an operation sequence in an example of a conventional screen printing apparatus.

[Explanation of symbols]

 1a, 1b Scriber 1c Rubber shoe 1d Base 2a, 2b Sensor 3 Screen 4 Resin supply nozzle 5a, 5b Squeegee head 6a, 6b Squeegee 7 Feed table 8 Resin 9 Mask part 10 Electronic component 11 Threading resin

Claims (3)

[Claims] 1. A mask portion having a screen having opening holes having the same through hole pattern as the resin coating pattern, a resin supply nozzle for dropping an appropriate amount of resin on the screen, and the dropped resin on the screen. In a screen printing apparatus including a squeegee head including a squeegee that extends the resin into the opening hole and applies the resin to the electronic component, the stringing of the resin that occurs when the squeegee is raised after applying the resin is performed. A screen printing device comprising a scriber that wipes while moving. 2. The screen printing apparatus according to claim 1, further comprising a sensor that detects the presence or absence of stringing of the resin. 3. The screen printing apparatus according to claim 1, wherein the scriber is provided with a soft rubber member having unevenness on the surface.