JPH10250043A - Method and device for screen printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute cleaning of a screen without stopping an automatic printing process and without using manpower. SOLUTION: A printing paste is applied to a screen 12 which has a predetermined printing pattern formed thereon and is suspended by a predetermined tension. A squeezee 14 is moved by being brought into line-contact with the screen 12 to spread the printing paste on the screen 12 and the lower face of the screen 12 is brought into contact with a top face of a printing medium 11 on a printing table 10 to print the printing paste on the face to be printed of the printing medium by a predetermined pattern. At that time, a cleaning sheet 17 placed on a second printing table 7 is disposed under the screen 12 by every one or more times of printing on the face to be printed of the printing medium 11 placed on the first printing table 10, then printing is performed on the cleaning sheet 17 instead of the printing medium 11 by using the screen 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for screen-printing ceramic green sheets using a printing paste such as a conductive paste or a solder paste in order to manufacture a laminated electronic component or a hybrid integrated circuit. Especially,
The present invention relates to a screen printing method and apparatus having a cleaning function for eliminating clogging of a screen due to dust or the like and always enabling high quality printing.

[0002]

2. Description of the Related Art Internal electrode patterns are printed on ceramic green sheets for manufacturing laminated electronic components,
When printing a solder paste for mounting a chip-shaped component on a hybrid integrated circuit board, a screen printing method is used. The screen used for this screen printing method is
A screen is stretched inside the screen frame under a required tension, and a mask having holes corresponding to the printing pattern is stretched on the screen. The screen is arranged on a printing surface of a printed material such as a ceramic green sheet set on a printing table, and a printing paste such as a conductive paste is applied on the screen. Then, the squeegee is moved in a direction perpendicular to the width direction in a state where the blade edge of the blade-shaped squeegee is brought into line contact with the screen and the screen is bent downward. Thereby, the printing paste is spread on the screen, and the mask is brought into contact with the printing surface of the printed matter. In this manner, the printing paste is extruded from the holes of the mask onto the printing surface of the printed matter, applied, and printed.

In such a screen printing method, different printed materials are sequentially and repeatedly printed using the same screen. However, if the printing is repeated several times, the holes of the mask are clogged with dust or dry printing paste. Therefore, conventionally, before the mask is clogged, the printing apparatus is periodically stopped and the lower surface of the screen is cleaned by wiping with a cloth or the like containing a cleaning solvent. Alternatively, every time an appropriate number of printed materials are printed, the printing pattern of the printed materials is inspected, and when a print blur is found, the screen is cleaned as described above.

[0004]

In such a screen printing method, the automation of the process is progressing. However, in order to clean the screen during repeated printing, the screen printing apparatus must be stopped each time. Then, the lower surface of the screen must be manually wiped.
Therefore, every time cleaning is performed, the automatic operation of the screen printing apparatus is stopped, the operating rate is reduced, and labor is required as a factor for cleaning. Further, when the lower surface of the screen is wiped off with a cloth or the like impregnated with a cleaning solvent, there is another problem that the dirt is transferred to other parts of the lower surface of the screen unless it is carefully wiped off.

The present invention has been made in view of such a conventional problem,
A screen printing method that can be easily incorporated into the automatic printing process, thereby enabling the screen to be cleaned without stopping the automatic printing process, and completely cleaning the screen without manual operation. It is intended to provide a device.

[0006]

That is, in the present invention,
In order to achieve the above object, each time printing is performed on the printing surface of the printed matter 11 using the screen 12, the printed matter 11
Instead of this, by printing on the cleaning sheet 17 with the screen 12, the adhered matter attached to the lower surface or the hole of the screen 12 is adhered to the adhesive surface of the cleaning sheet 17 and removed.

That is, in the screen printing method according to the present invention, if a predetermined printing pattern is formed, the printing paste 20 is applied to the screen 12 stretched by applying a required tension, and the squeegee 14 is brought into line contact with the screen 12. Moves and spreads the print paste 20 on the screen 12, contacts the lower surface of the screen 12 on the print 11 on the print table 10, and prints the print paste 20 in a predetermined pattern on the print surface of the print 11. In doing so, each time printing is performed on the printing surface of the printed material 11 on the first printing table 10 at least once, a cleaning sheet 17 is placed on the second printing table 7 below the screen 12 and the printed material 11 is printed. Instead, printing is performed on the cleaning sheet 17 using the screen 12.

Further, a screen printing apparatus for performing such a screen printing method includes a screen 1 on which a predetermined printing pattern is formed and which is stretched by applying a required tension.
2 and a printed matter 1 placed just below the screen 12.
1 is placed on the print table 10 and the screen 12 is brought into line contact with the line, the print paste 20 is spread on the screen 12, and the lower surface of the screen 12 is brought into contact with the printed material 11 on the print table 10. A squeegee 14 for causing the first print table 10 to reciprocate relative to the screen 12 between a position directly below the screen 12 and a position retracted from directly below the screen 12; Moves the screen 1 between another second printing table 7 and a position immediately below the screen 12 and a position retracted from immediately below the second printing table 7.
And a cleaning sheet supply mechanism for supplying a cleaning sheet 17 onto the second printing table 7.

In this case, the cleaning sheet 17 is formed in a long tape shape, and is fed at least by the length to be printed each time printing is performed thereon. For example, a supply reel 4 that supplies a long cleaning sheet 17 onto the second printing table 7 and a collection reel 5 that winds up the printed cleaning sheet 7 that has passed through the second printing table 7 are provided. Each time printing is performed on the cleaning sheet 17, a long cleaning sheet 17 is supplied from the supply reel 4 for at least the length to be printed on the second print table 7, and the printed cleaning is performed. The use sheet 7 is wound up on the collection reel 5. It is preferable that the cleaning sheet 7 has a surface coated with an adhesive to form an adhesive surface, and the adhesive surface is printed using a screen.

In such a screen printing method and apparatus, the operation of printing on the cleaning sheet 17 instead of the printed material 11 only needs to be inserted in the operation of sequentially and repeatedly printing using the screen 12. 12
The screen 12 can be periodically cleaned without stopping the operation of the automatic repetitive printing using. Moreover, since printing is performed on the cleaning sheet 17 using the screen 12, dirt and the like adhered to the holes on the lower surface of the screen 12 adhere to the cleaning sheet 17 together with the printing paste. The screen 12 can be easily separated from the cleaning sheet 17 by keeping the cleaning sheet 17 in close contact with the second printing table 7. At this time, the dirt adhering to the screen 12 is peeled off while being adhered to the cleaning sheet 17. Therefore, the screen 12 can be completely cleaned without transferring dirt. In particular, when using an adhesive sheet as a cleaning sheet and printing using a screen on this adhesive surface, the residue and dust of the hardened printing paste are strongly adhered to the adhesive surface around the screen holes. Since it is peeled off from the surface, the cleaning effect is extremely high.

[0011]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
FIG. 1 shows an entire screen printing apparatus according to the present invention. A guide rail 1 is installed on the floor, and a printed matter holding unit 9 and a cleaning unit 3 are slidably installed along the guide rail 1.

The printed matter holding unit 9 is mounted on the guide rail 1 by guide bushes 8 and 8 and is moved along the guide rail 1 by a driving mechanism (not shown) as shown by arrows. A first print table 10 having a flat upper surface is provided on the print holding unit 9. The printed material holding unit 9 moves leftward from the position shown in FIG. 1, and the printed material 11 such as a ceramic green sheet is placed on the flat upper surface of the first print table 10 at a position retracted from directly below the screen 12 and fixed. Is done. For example, on both sides of the position where the printed material holding unit 9 is retracted right below the screen 12, a stocker (not shown) that stores unprinted printed materials 11 and a stocker that stores printed printed materials 11 are arranged. The printed material 11 is placed on the first print table 10 from a first unprinted print stocker by a transport mechanism (not shown), and is printed from the first print table 10 to the printed print stocker after printing is completed. Is conveyed. In addition, as a fixing means of the printed matter 11 on the printing table 10, for example, a vacuum suction force or the like is used.

In FIG. 1, a screen 12 is arranged above the stop of the printed matter holding unit 9. For example, a screen 12 is formed by applying a predetermined tension to a square frame-shaped screen frame 13 to stretch a mesh screen, and stretching a metal mask made of a thin metal plate having a hole in the center of the screen. I have. The holes of the metal mask correspond to the shape of the print pattern to be printed on the print surface of the print 11. The screen 12 may use a metal mask formed of such a thin metal plate, or may use a screen having holes formed by photoetching using an emulsion.

The drive unit 1 is placed on the screen 12.
A squeegee 14 which is moved up and down by 5 is arranged.
The squeegee 14 has a blade shape, and its sharp edge is applied over the width direction of the upper surface of the screen 14. The drive unit 15 is reciprocated in a direction indicated by an arrow in FIG. 1 along a guide rail 16 provided on the screen 12.

On the other hand, a cleaning unit 3 slidably disposed along the guide rail 1 is mounted on the guide rail 1 by guide bushes 2 and 2, and is moved along the guide rail 1 by a driving mechanism (not shown). Move as shown by the arrow. On this cleaning unit 3, a second printing table 7 is provided,
Its upper surface is flat. A pair of guide rollers 6 having a cylindrical guide surface which is long in FIG. 1 is provided before and after the second printing table 7.

The cleaning unit 3 is provided with a supply roll 4 on which a long cleaning sheet 17 is wound, and the cleaning sheet 17 wound on the supply reel 4 is provided.
Are sent from the guide rail 6 onto the second printing table 7, are placed on the upper surface thereof, pass through the other guide rail 6, and are further guided by other guide rails 6, 6. It is wound up. The supply reel 4 and the collection reel 5 rotate intermittently in synchronization with each other, and the cleaning sheet 1 is rotated.
7 is sent at regular intervals. The feed pitch is equal to or longer than a length to be printed on the cleaning sheet 17 using the screen 12 as described later.

The cleaning sheet 17 is made of low dusting paper for clean room or polyethylene terephthalate (PE).
T) A polymer film such as a film, or a film using them as a base material, and an adhesive is thinly and uniformly applied to one surface thereof. For example, Hitachi Chemical Gitalex G
P-5 and S.T. P. V. And other wide adhesive tapes can be used. This cleaning sheet 1
7 is placed on the second printing table 7 and
On the second printing table 7, that is, the guide rollers 6,
6, a sufficient tension is applied to the second printing table 7
Fixed on top. In order to securely hold the cleaning sheet 17 on the second printing table 7, vacuum suction means or the like may be used. When an adhesive sheet is used as the cleaning sheet 17, the adhesive sheet is placed on the second printing table 7 so that the adhesive surface faces upward.

Next, a method of printing on the printing surface of the printed material 11 while cleaning the screen 12 using the screen printing apparatus will be described below. First, the printed matter 11 is placed at a predetermined position on the print table 10 while the printed matter holding unit 9 moves leftward from the position shown in FIG. Thereafter, the print holding unit 9 returns to the position shown in FIG.

At this position, the printing paste is applied on the screen 12, and the printing paste is spread in the width direction of the screen (the front-back direction in FIG. 1) by a scraper (not shown). Thereafter, as shown in FIG. 2, the squeegee 14 is lowered, and the cutting edge of its tip is pressed linearly against the screen 12, whereby the linear portion is lowered against the tension of the screen 12, and Abut. In this state, the squeegee moves leftward in FIG. 2 and the print paste is developed on the screen 12. As a result, the printing paste is extruded and adheres to the printing surface of the printed material 11 through the holes of the screen 12, and the printed paste is printed.
Is printed on the printing surface according to the pattern of the holes of the screen 12.

Thereafter, as the squeegee 14 rises,
Return to the original position. Further, the printed matter holding unit 9 is arranged as shown in FIG.
At the left side, the printed material 11 having been printed is removed from the first print table 10 and stored in a stocker (not shown), and the printed material 11 to be printed next is supplied. It is put on a predetermined position. Thereafter, printing on the printing surface of the printed material 11 is performed in the same manner as described above.

If the printing operation on the printed surface of the printed material 11 is repeated by such a printing operation, dirt gradually adheres to the holes of the screen 12. FIG. 8 schematically shows this state. As shown in FIG.
Adheres to the peripheral wall of the hole 18 of the screen 12 and substantially reduces the cross-sectional area of the hole 18. For this reason, the print pattern may be blurred or cut off, resulting in poor printing.

Thus, the hole 1 of the screen 12
The screen 12 is cleaned before the attached matter 22 adheres to the print 8 and affects the print pattern. That is,
After printing is performed on an appropriate number of printing materials 11 by the operation described above, the next printed material 11 is printed on the first printing table 10.
The print holding unit 9 is placed on the screen 12
While evacuating from just below the cleaning unit 3
1 moves leftward in FIG. 1, and the second print table 7 moves directly below the screen 12 as shown in FIG. 3.

Here, the screen 1 is printed on the cleaning sheet 17 in the same manner as the printing on the printed material 11 as described above.
2, printing of the printing paste is performed. At this time, tension is applied to the cleaning sheet 17 or the cleaning sheet 17 is moved to the second printing table 7 by vacuum suction means or the like.
In close contact with the upper surface of the FIG. 5 shows an operation of printing the printing paste 20 with the screen 12 on the adhesive surface of the cleaning sheet 17 made of an adhesive sheet. In FIG. 5, reference numeral 21 denotes an adhesive layer applied to the surface of the cleaning sheet 17.

As described above, the print paste 20 provided on the screen 12 is extended in the front-rear direction in FIG. 5 by a scraper (not shown). Further, the cutting edge at the tip of the squeegee 14 is pressed linearly against the screen 12, and the linear portion descends against the tension of the screen 12, and comes into contact with the adhesive surface of the cleaning sheet 17. In this state, the squeegee moves leftward in FIG. 2, and the print paste is spread on the screen 12. Thereby, the printing paste 20 is extruded and adheres to the adhesive surface of the cleaning sheet 17 through the holes 18 of the screen 12. At this time, the deposit 19 extruded from the hole 18 of the screen 12 together with the printing paste 20 adheres to the adhesive surface of the cleaning sheet 17 together with the printing paste 20.
Then, when the squeegee 14 passes, the screen 12
Is separated from the adhesive surface of the cleaning sheet 17 by the tension. At this time, since the attached matter 19 and the printing paste 20 are more strongly adhered to the adhesive surface of the cleaning sheet 7 than the screen 12, It peels off and remains attached to the adhesive surface of the cleaning sheet 17. As a result, the deposits 19 are completely removed from the holes 18 and the like of the screen 12. Thus, the screen 12 is cleaned. The adhesive surface of the cleaning sheet 17 is
Since it has an extremely strong adhesive force as compared with the surface of the print 1, the print 19 adheres to the screen 12 at the time of the printing operation and the print 19 remaining on the screen 12 can be reliably removed.

Thereafter, the cleaning unit 3 is returned to the original position, and the cleaning sheet 17 is fed from the supply reel 4 for one pitch, and the cleaning sheet 17 is fed to the collection reel 5.
Is wound and a new adhesive film 17 having a clean adhesive surface on which the printing paste 20 and the deposit 19 are not adhered.
Is placed on the second print table 7. Thereafter, the printed matter holding unit 9 is moved directly below the screen 12 as shown in FIGS. 1 and 2, and printing on the printed surface of the printed matter 11 is performed as described above.

This cleaning operation is performed for each predetermined number of printed sheets 11 of printed material. The number of times of printing during this cleaning operation is determined by testing the number of times of printing until the attachment 19 adheres to the screen 12 after cleaning the screen 12 and affects the printing pattern. Set a small number of prints with. The screen printing process including such a cleaning operation is controlled automatically by a sequencer or a computer, and is automatically performed according to the set number of times. In the above example, the screen 12 is fixed,
Although the printed matter holding unit 9 and the cleaning unit 3 are moved, the printed matter holding unit 9 and the cleaning unit 3 may be fixed and the screen 12 may be moved.

[0027]

As described above, in the screen printing method and apparatus according to the present invention, the screen 12 can be periodically cleaned without stopping the operation of automatic repetitive printing using the screen 12. Also completely,
In addition, the screen 12 can be cleaned without transferring dirt to another. As a result, it is possible to perform screen printing efficiently and with high print quality without human intervention.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a screen printing apparatus according to the present invention.

FIG. 2 is a schematic side view of a main part in a state where printing is performed on a printed material by the screen printing apparatus.

FIG. 3 is a schematic side view of a main part in a state where printing is performed on a cleaning sheet by the screen printing apparatus and the screen is cleaned.

FIG. 3 is an enlarged vertical sectional side view of a main part of the screen, schematically showing a state of contamination of the screen in the screen printing apparatus.

FIG. 5 is a schematic enlarged vertical cross-sectional side view of a main part in a state where printing is performed on a cleaning sheet by the screen printing apparatus and the screen is cleaned.

[Explanation of symbols]

 Reference Signs List 4 supply reel 5 collection reel 7 second print table 10 first print table 11 printed matter 12 screen 14 squeegee 17 cleaning sheet 20 print paste

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[Procedure amendment]

[Submission date] May 31, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Oath

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a screen printing apparatus according to the present invention.

FIG. 2 is a schematic side view of a main part in a state where printing is performed on a printed material by the screen printing apparatus.

FIG. 3 is a schematic side view of a main part in a state where printing is performed on a cleaning sheet by the screen printing apparatus and the screen is cleaned.

FIG. 4 is an enlarged vertical sectional side view of a main part of the screen, schematically showing a state of contamination of the screen in the screen printing apparatus.

FIG. 5 is a schematic enlarged vertical cross-sectional side view of a main part in a state where printing is performed on a cleaning sheet by the screen printing apparatus and the screen is cleaned.

[Description of Signs] 4 Supply reel 5 Collection reel 7 Second print table 10 First print table 11 Printed matter 12 Screen 14 Squeegee 17 Cleaning sheet 20 Print paste

Claims (6)

[Claims] When a predetermined printing pattern is formed, a printing paste (20) is applied to a screen (12) stretched by applying a required tension, and a squeegee (14) is brought into line contact with the screen (12). Moves and the screen (1
2) The print paste (20) is spread on the upper surface, and the lower surface of the screen (12) is brought into contact with the printed material (11) on the print table (10), so that a predetermined pattern is formed on the printed surface of the printed material (11). In the screen printing method for printing the printing paste (20) with the first printing table (1),
0) A printing sheet (17) is placed on a second printing table (7) under the printing screen (12) every time printing is performed on the printing surface of the printed material (11) on the upper side at least once. A screen printing method characterized in that printing is performed on the cleaning sheet (17) using a screen (12) instead of (11). 2. The cleaning sheet (17) is in the form of a long tape, and is fed at least by the length to be printed each time printing is performed thereon. 2. The screen printing method according to 1. 3. The cleaning sheet (17) is made of an adhesive sheet, placed on a second printing table (7) with its adhesive surface facing upward, and printed on the adhesive surface. The screen printing method according to claim 1. 4. A screen (12) on which a predetermined print pattern is formed and stretched by applying a required tension, and a print table (10) disposed immediately below the screen (12) and on which a printed matter (11) is placed. And the screen (12)
The line is moved into contact with the line, and the printing paste (20) is spread on the screen (12), and the lower surface of the screen (12) is brought into contact with the printed matter (11) on the printing table (10). In a screen printing apparatus provided with a squeegee (14), the first printing table (10) is reciprocated relative to the screen (12) between a position directly below the screen (12) and a position retracted from directly below the screen. Mechanism and the first printing table (10)
Reciprocating relative to the screen (12) between the second printing table (7), which is different from the first printing table (7), and a position directly below the screen (12) and a position retracted from therebelow. Mechanism for causing the second print table (7)
A screen printing apparatus comprising a cleaning sheet supply mechanism for supplying a cleaning sheet (17) thereon. 5. A supply reel (4) for feeding a long cleaning sheet (17) onto a second printing table (7), and a printed cleaning sheet passing through the second printing table (7). 5. The screen printing apparatus according to claim 4, further comprising a collecting reel for winding the sheet. 6. The cleaning sheet (17) is made of an adhesive sheet and is placed on a second printing table (7) with its adhesive surface facing up, and is printed on the adhesive surface. The screen printing method according to claim 4.