JP2001253045A - Squeegee head for screen printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a squeegee head for screen printing capable of reducing labour for preparation work and a waste of a paste. SOLUTION: The squeegee head 13 for screen printing stores a cream solder 5 in a printing space 35 formed of scraping members 36A, 36B and prints a base plate via pattern pores of a mask plate. In this case, when the head 13 is separated from the mask plate, a case-like cover member 41 is slid horizontally while pressing ends of the scraping members 36A, 36B by a tapered surface 41c to be mounted on the head 13, and an opening 35a is blocked by an upper surface 41a. Thus, the solder 5 in the head 13 can be prevented from being deteriorated in its quality due to exposure with an atmosphere and an oxidation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing squeegee head for printing paste such as cream solder or conductive paste on a substrate.

[0002]

2. Description of the Related Art In an electronic component mounting process, screen printing is used as a method for printing paste such as cream solder or conductive paste on a substrate. In this method, a mask plate having pattern holes formed in accordance with a printing target portion is set on a substrate, and the paste is printed on the substrate through the pattern holes of the mask plate by squeezing.

As a squeezing method for screen printing, a method using a closed squeegee head is known. This method uses a squeegee head provided with a paste storage container, instead of directly supplying the paste onto a mask plate unlike normal screen printing. In this method, the paste in the paste storage container is pressed into the pattern hole of the mask plate through the opening by pressing the paste in the paste storage container with the opening provided on the lower surface of the paste storage container being in contact with the mask plate. It is. Then, the squeegee head is slid on the mask plate to sequentially fill each pattern hole with the paste.

[0004]

However, screen printing using the above-mentioned conventional closed-type squeegee head involves the following.
There were the following problems. In the closed squeegee head, the paste is supplied into the squeegee head, unlike the conventional printing method in which the paste is supplied directly on the screen mask. Therefore, when the squeegee head is removed and stored, or when printing is temporarily suspended and the squeegee head is raised from the screen mask, the paste stored in the squeegee head is exposed to the atmosphere through the opening. there were.

[0005] For this reason, the paste on the opening surface has been in contact with the air for a long period of time, so that the oxidation reaction has progressed, and the wettability has been reduced, resulting in poor quality in a later step. And in order to prevent this quality deterioration, it is necessary to remove the paste on the opening surface and discard it before starting production after interruption,
In the conventional squeegee head, it is necessary to partially remove and dispose of the pasted paste in order to prevent the quality of the paste from deteriorating, and thus there is a problem in that work preparation is required and the paste is wasted.

Accordingly, an object of the present invention is to provide a squeegee head for screen printing that can eliminate the trouble of preparation for work and waste of paste.

[0007]

According to a first aspect of the present invention, there is provided a squeegee head for screen printing, wherein a paste is stored inside the squeegee head, and the squeegee head is slid on the mask plate in a state where the paste is pressurized. A screen printing squeegee head that prints paste on a substrate through holes, a paste storage unit that stores the paste, a paste pressing unit that presses the paste in the paste storage unit, and a pressurized paste. A printing space to be housed and brought into contact with the surface of the mask plate, two scraping members forming front and rear walls in the squeezing direction of the printing space and having a lower end provided in contact with the surface of the mask plate; An opening formed by two scraping members to bring the paste into contact with the surface of the mask plate, Squeegee head is mounted on has a cover member for closing the opening in a state spaced apart from the screen mask.

The squeegee head for screen printing according to claim 2 is the squeegee head for screen printing according to claim 1, wherein the cover member presses the end of the scraping member from the horizontal direction. It is attached to and detached from the squeegee head.

According to the present invention, in a state where the squeegee head is separated from the screen mask, the opening for bringing the paste into contact with the surface of the mask plate is covered by the cover member detachably attached to the squeegee head. It is possible to prevent quality deterioration due to the paste in the squeegee head being exposed to the air and being oxidized.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a front view of a screen printing apparatus according to one embodiment of the present invention, FIG. 2 is a side view of the screen printing apparatus according to one embodiment of the present invention, and FIG. 3 is a screen printing apparatus according to one embodiment of the present invention. FIG. 4 is an inverted perspective view of a squeegee head of a screen printing apparatus according to an embodiment of the present invention, and FIGS. 5 and 6 are squeegee heads of a screen printing apparatus according to an embodiment of the present invention. FIG. 7 is a partial sectional view of a squeegee head of a conventional screen printing apparatus.

First, the structure of the screen printing apparatus will be described with reference to FIGS. 1 and 2, the substrate positioning unit 1 is configured by disposing a substrate holding unit 2 on a moving table (not shown). The substrate 3 to be screen-printed is held by a clamper 4 of the substrate holding unit 2, and by driving a moving table (not shown), the substrate 3 held by the substrate holding unit 2 is positioned in the horizontal and vertical directions. .

A screen mask 10 is provided above the positioning section 1. The screen mask 10 is configured by mounting a mask plate 12 on a holder 11, and a pattern hole 12 a corresponding to a printing portion of the substrate 3 to be printed is formed in the mask plate 12.

A squeegee head 13 is arranged on the screen mask 10 so as to be movable up and down by a head elevating unit 20. The head elevating unit 20 includes a cylinder 22 erected on a plate member 21, and the squeegee head 13 is coupled to a lower end of a rod 22 a of the cylinder 22 via a coupling member 15. By driving the cylinder 22, the squeegee head 13 moves the mask plate 12
To go up and down. The head lifting / lowering unit 20 serves as lifting / lowering means for lifting / lowering the squeegee head 13 with respect to the screen mask 10.

Sliders 23 are fixed at both ends to the lower surface of the plate member 21 of the head elevating unit 20, and the slider 23 is slidably fitted on a guide rail 24 provided on the upper surface of the frame 25. I have. A nut 26 is connected to the lower surface of the plate member 21, and a feed screw 27 screwed to the nut 26 is driven to rotate by a motor 28.

By driving the motor 28, the plate member 21 moves horizontally, and therefore the head lifting / lowering unit 20 is moved.
Is also moved horizontally. By driving the motor 28 with the squeegee head 13 lowered, the squeegee head 13 moves horizontally on the mask plate 12. That is, the motor 28, the feed screw 27, and the nut 26 are moving means for horizontally moving the squeegee head 13 on the mask plate 12.

At the lower part of the squeegee head 13, there is provided a printing section 14 which abuts on the surface of the mask plate 12 and fills the pattern holes 12a with the cream solder 5 as a paste. The structure of the printing unit 14 will be described with reference to FIG. In FIG. 3, reference numeral 30 denotes a main body, which is a block-shaped member elongated in the width direction of the mask plate 12. The length of the main body 30 is set so as to cover the width of the substrate 3 to be printed as shown in FIG. Main unit 30
Is formed with a concave portion 30a in which the cartridge 31 storing the cream solder 5 is detachably mounted.

The cartridge 31 is a reservoir (paste reservoir) for the cream solder 5 in which a predetermined amount of the cream solder 5 is stored in advance, and is mounted on the main body 30 at the time of printing. A pressure plate 32 for pressing the cream solder 5 inside is fitted into the opening on the upper surface of the cartridge 31. The pressure plate 32 is connected to the rod 16a of the cylinder 16 disposed above, and by driving the cylinder 16,
The pressure plate 32 moves up and down in the cartridge 31.

The bottom surface of the cartridge 31 is an extruding plate 31a for the cream solder 5;
A large number of openings 31b are provided in 1a. Pressure plate 3
When the cylinder 2 is pressed downward by the cylinder 16, the cream solder 5 in the cartridge 31 is pressed, and is pushed downward through the opening 31b of the push plate 31a. The cylinder 16 and the pressing plate 32 serve as pressing means for pressing the cream solder 5.

At the bottom of the main body 30, a cartridge 31 is provided.
A diaphragm plate 34 provided with a large number of openings 34a is mounted similarly to the extrusion plate 31a. When the cream solder 5 is extruded by the cylinder 16, the extruding plate 3
It passes through the opening 31b of 1a and the opening 34a of the diaphragm plate 34 in two stages and moves downward. The extruded cream solder 5 forms a space formed below the main body 30, that is, two scraping members 36 </ b> A and 36 </ b> B disposed obliquely inside the lower part of the main body 30 and the lower surface of the main body 30. And arrives at the printing space 35 surrounded by.

The scraping members 36A and 36B form front and rear walls of the printing space 35 in the squeezing direction, and when the squeegee head 13 is lowered, the scraping members 36A and 36B are formed.
The lower end of 6B contacts the surface of the mask plate 12. During the printing operation, the printing space 35 contains the pressurized cream solder 5 and brings the cream solder 5 into contact with the surface of the mask plate 12 through the opening between the scraping members 36A and 36B.

The pressure plate 32 is depressed so that the cartridge 31
By pressing the cream solder 5 inside, the cream solder 5 passes through the extruding plate 31a and the squeezing plate 34 and moves into the printing space 35. In the middle of the movement path of the cream solder 5, a narrow portion whose cross-sectional area is narrowed by a number of small openings 31b and 34a is formed. The viscosity of the solder 5 is reduced, and the solder 5 is modified into a property suitable for screen printing.

In the screen printing, the cream solder 5 inside is pressurized by the pressing plate 32, and the squeegee head 13 in a state where the cream solder 5 modified to the appropriate viscosity as described above is filled in the printing space 35. Is slid on the mask plate 12. As a result, the cream solder 5 in the printing space 35 is filled into the pattern holes 12a of the mask plate 12 through the openings between the scraping members 36A and 36B.

By moving the squeegee head 13, the cream solder 5 is sequentially filled in each pattern hole 12a. When the cream solder 5 is filled in all the pattern holes 12a, the substrate holding unit 2 is lowered to release the plate. That is, the cream solder 5 in the pattern hole 12a descends together with the substrate 3 and
, Whereby the screen printing of the cream solder 5 on the substrate 3 is completed.

When the predetermined printing operation is completed, a cover is mounted for the purpose of preventing the quality of the cream solder 5 inside the squeegee head 13 from deteriorating. As shown in the present embodiment, in the method using the closed type squeegee, the cream solder 5 in the printing space 35 is removed from the printing space 35 when the squeegee head 13 is raised from the mask plate 12 or when the squeegee head 13 is removed. The state is exposed to the atmosphere through the opening 35. When the cream solder 5 is exposed to the atmosphere for a long time, the cream solder 5 on the surface is oxidized by oxygen in the atmosphere, and the quality is deteriorated.

For this reason, when the squeegee head 13 is removed or when the squeegee head 13 is lifted from the mask plate 12, it is desirable to cover the opening of the printing space 35 by an appropriate method. Therefore, in the present embodiment, a cover member that covers the opening is detachably provided.

Next, a cover member for closing the opening of the printing space 35 of the squeegee head 13 will be described with reference to FIGS. FIG. 4 shows a state in which the squeegee head 13 is inverted, that is, a state in which the opening of the printing space 35 formed by the two scraping members 36A and 36B and bringing the cream solder 5 into contact with the surface of the mask plate 12 faces upward. I have.

4 and 5, a cover member 41 is a flat, substantially box-shaped member made of a thin plate such as a stainless steel plate, and has an upper surface 41a, two side surfaces 41b, and a rear surface 41.
f. The surface corresponding to the lower bottom of the cover member 41 is removed leaving only the side bottom surface 41g of the side edge.

The front ends of the upper surface 41a, the two side surfaces 41b and the side bottom surface 41g are respectively provided with tapered surfaces 41c and 41g.
The cover member 41 functions as a guide surface when the cover member 41 is mounted on the squeegee head 13 to facilitate the mounting operation. At the time of mounting, the cover member 4 is pushed by pushing the side bottom surface 41 g along the mounting surface 42 provided at the side end of the squeegee head 13.
1 can be mounted on the squeegee head 13. Here, the height dimension h of the cover member 41 is smaller than the distance between the mounting surface 42 of the squeegee unit 13 and the ends of the scraping members 36A and 36B on both sides of the opening 35a by a predetermined pushing allowance d. It is set small.

When the cover member 41 is mounted, the opening 35a of the printing space 35 is closed by the upper surface 41a, and the cream solder 5 exposed in the opening 35a is attached to the upper surface 41a. Therefore, the quality deterioration due to the cream solder 5 in the opening 35a coming into contact with oxygen in the atmosphere does not progress.

Next, the operation of attaching and detaching the cover member 41 to and from the squeegee head 13 will be described with reference to FIG. As shown in FIG. 6, when the cover member 41 is mounted on the squeegee unit 13 by sliding the cover member 41 in the direction of arrow a, the scraping members 36A and 36B are pushed by the tapered surface 41c. Slide while bending only downward.

As a result, the tapered surface 41c is
At a, it contacts the surface of the cream solder 5 and moves while pushing the cream solder 5 in the sliding direction. Therefore, no bubbles remain in the cream solder 5 in a state where the cover member 41 covers the opening 35, and the deterioration of the cream solder 5 due to the remaining bubbles can be prevented. In addition,
FIG. 7A shows, for reference, a state in which an opening of a printing space of a similar squeegee head is simply covered from above by a flat cover member 43. It is understood that when such a cover method is used, voids 44 are likely to be generated due to air remaining in the opening after the cover is attached.

Also, when removing the cover member, the
The cover member 41 is slid in the horizontal direction (the direction of the arrow b) opposite to the mounting direction shown in FIG. In this sliding operation, the opening 3 which was in close contact with the inner surface of the cover member 41
The cream solder 5a is sheared on the surface of the upper surface 41a of the cover member 41 to release the close contact state, and the cover member 41 can be removed without the cream solder 5 adhering to the upper surface 41a. That is, the adhesion of the cream solder 5 that tends to occur when the cover member 43 is removed upward from the cover state as shown in FIG. 7B does not occur.

As described above, the cover member 41 is attached to and detached from the opening 35a from the horizontal direction while pressing the ends of the scraping members 36A and 36B. By using such a cover member 41, it is possible to prevent bubbles from remaining in the cream solder 5 as described above, and to prevent the cream solder 5 from adhering to the inner surface of the cover member 41 when the cover member 41 is removed. In addition, the maintenance of the cover member 41 can be easily performed, and the amount of the cream solder 5 that is unnecessarily discarded can be reduced, thereby eliminating waste of resources.

[0034]

According to the present invention, when the squeegee head is separated from the screen mask, the opening for bringing the paste into contact with the surface of the mask plate is covered by the cover member detachably attached to the squeegee head. As a result, the quality of the paste in the squeegee head can be prevented from being deteriorated due to exposure to the atmosphere and being oxidized. Paste can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a side view of the screen printing apparatus according to the embodiment of the present invention.

FIG. 3 is a partial sectional view of a squeegee head of the screen printing apparatus according to the embodiment of the present invention;

FIG. 4 is an inverted perspective view of a squeegee head of the screen printing apparatus according to the embodiment of the present invention;

FIG. 5 is a partial cross-sectional view of a squeegee head of the screen printing apparatus according to one embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a squeegee head of the screen printing apparatus according to one embodiment of the present invention.

FIG. 7 is a partial sectional view of a squeegee head of a conventional screen printing apparatus.

[Explanation of symbols]

 Reference Signs List 3 board 5 cream solder 12 mask plate 12a pattern hole 13 squeegee head 14 printing unit 16 cylinder 20 head elevating unit 22 cylinder 31 cartridge 32 pressure plate 35 printing space 35a opening 41 cover member

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/34 505 H05K 3/34 505D (72) Inventor Minoru Murakami 1006 Odakadoma, Kadoma City, Osaka Matsushita Electric Within Sangyo Co., Ltd. (72) Inventor Michinori Tomomatsu 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F-term (reference)

Claims (2)

[Claims] 1. A method according to claim 1, wherein the paste is stored inside and is slid on a mask plate in a state where the paste is pressed.
A squeegee head for screen printing for printing paste on a substrate through a pattern hole of a mask plate,
A paste storage unit for storing the paste, a paste pressing unit for pressing the paste in the paste storage unit, a printing space for receiving the pressed paste and contacting the surface of the mask plate, and a squeezing direction of the printing space Two scraping members that form the front and rear walls of which the lower end is provided in contact with the surface of the mask plate, and an opening that is formed by these two scraping members and makes the paste contact the surface of the mask plate; A squeegee head for screen printing, comprising: a cover member detachably mounted on the squeegee head and closing the opening when the squeegee head is separated from the screen mask. 2. The squeegee head according to claim 1, wherein the cover member is attached to and detached from the squeegee head from a horizontal direction while pressing an end of the scraping member.
A squeegee head for screen printing as described.