JPH05147194A - Device for covering paste and scraping paste from squeegee - Google Patents

Abstract

PURPOSE:To remove paste solder from the squeegee of a screen printing machine to prevent it from falling from the squeegee. CONSTITUTION:The title device is composed of a paste cover 50 provided freely movably to a screen frame 12 which a printing screen 11 is fixed to, an engaging part which is provided to the paste cover 50 and is engaged with a squeegee 1 side of a screen printing machine, and a pressure contact mechanism which brings a paste scratching off part of the paste cover 50 into pressure contact with a side surface of the squeegee.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeegee adhering paste scraping / covering device for a screen printing machine for printing a paste such as cream solder on a substrate.

2. Description of the Related Art In a recent screen printer for cream solder or the like, it has been proposed to perform plate alignment between the screen and the substrate by a visual recognition method, and accordingly, paste such as cream solder is applied to the screen. There has been a case where the squeegee itself has to be moved to a position away from the original printing range during the visual recognition work instead of moving back and forth only within the original printing range. Therefore, when the squeegee was moved, the paste such as cream solder attached to the squeegee did not completely cut due to the viscosity even after printing was completed, and moved in the stringed state, and in some cases, the paste dropped. It was Such dropping of the paste to a meaningless position not only wastes the paste but also makes it impossible to perform plate alignment with the substrate if it falls on the alignment mark on the screen, and the paste is printed on the screen print pattern. If dropped, problems such as uneven printing and wraparound of the paste on the back side of the screen occur. In order to eliminate such a phenomenon of dropping the paste from the squeegee, conventionally, the roller 2 is closely attached to the side surface of the squeegee 1 with a spring or the like as shown in FIG. Relative movements are made along the side surfaces as indicated by imaginary lines P and Q to scrape off the adhered paste.

By the way, in the structure for scraping the paste by using the conventional roller 2 shown in FIG.
As shown in FIG. 13, when the roller 2 moves relative to the side surface of the squeegee 1 as indicated by phantom lines P and Q, the roller 2
However, there is a problem that the paste 3 rolls on the paste 3 and the adhered paste cannot be removed sufficiently. Furthermore, FIG.
As described above, a structure in which the paste adhered to the squeegee 1 is scraped off by the knife-shaped member 4 instead of the roller 2 is conceivable.
There is an inconvenience that it adheres to the lower surface of the and falls. In view of the above points, the present invention can sufficiently remove the paste such as cream solder adhered to the squeegee of the screen printing machine, and can surely prevent the phenomenon of dropping of the paste from the squeegee. The purpose is to provide a device.

In order to achieve the above object, a cover device for scraping and squeegeeing a paste for a squeegee according to the present invention includes a paste cover movably provided with respect to a screen frame and a paste cover for the paste cover. The structure is provided with an engaging portion that is provided and that engages with the squeegee side, and a pressure contact mechanism that presses the paste scraping portion of the paste cover against the side surface of the squeegee.

In the squeegee-attached paste scraping and covering device of the present invention, the paste scraping portion of the paste cover is pressed against the side surface of the squeegee of the screen printing machine,
It is possible to relatively move the side surface of the squeegee as the squeegee rises after printing the squeegee and sufficiently scrape off the paste such as cream solder attached to the side surface of the squeegee.
The scraped off paste is returned to the paste reservoir on the lower surface of the paste cover and reused. Furthermore, since the paste is partially covered with the paste cover to reduce the contact with the outside air, it is possible to prevent the flux contained in the paste from flying and reduce the temperature change of the paste to maintain the viscosity substantially constant. It is also possible to do this, and as a result,
Screen printing can be continued while maintaining almost the same conditions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a squeegee-adhering paste scraping and covering device according to the present invention will now be described with reference to the drawings. FIG. 1 shows the overall construction of an embodiment of the present invention. In this figure, 10 is a main frame of a screen printer, and a screen frame 12 for supporting a printing screen 11 made of stainless steel or the like is a support frame 13 on the main frame 10 side.
And is fixed to the support frame 13 when the piston rod of the screen frame fixing air cylinder 14 fixed to the machine frame side is extended. Reference numeral 20 denotes a substrate on which a paste such as cream solder is to be printed, which is positioned and held by a substrate suction support board 21 supported on the frame side of the machine. A squeegee unit 30 having a squeegee 1 for applying a paste such as cream solder is provided above the printing screen 11 in the X direction by an X direction drive mechanism 31 installed in the X direction with respect to the machine frame 10. It is movably supported. Left and right squeegee holders 32 are respectively supported by the squeegee unit 30 so as to be lifted and lowered, and the squeegee holders 32 are lifted and lowered by squeegee lift air cylinders 33A and 33B attached to the squeegee unit 30, respectively. And
The squeegee 1 is fixed to the left and right squeegee holders 32, respectively. Here, when the squeegee unit 30 is moved to the left in FIG. 1, the right squeegee holder 32 is lowered by the air cylinder 33A and the right squeegee 1 is used to apply the paste to the screen, and vice versa. When moving the squeegee unit 30 to the right in FIG. 1, the left squeegee holder 32 is lowered by the air cylinder 33B and the paste is applied to the screen using the left squeegee 1. A Y-direction drive mechanism 35 is installed on the side surface of the squeegee unit 30 in the longitudinal direction (Y-direction perpendicular to the paper surface of FIG. 1).
5, a TV camera 40 for visual recognition is supported so as to be movable in the Y direction. The TV camera 40 has a printing screen 1
The image is used to image the alignment mark that is normally formed in the corner portion of No. 1. The paste cover 50 is arranged on the printing screen 11 below the squeegee 1 in FIG. 1, and the paste cover 50 and the mechanical parts associated therewith are shown in detail in FIGS. 2 to 5. 2 to 5, the paste cover 50 covers the screen frame 12 in the Y direction.
A long member that traverses in the direction, a flat portion 51, a tapered portion 52 that is bent obliquely downward from both sides of the flat portion 51, and a roller attachment formed by extending to both ends of the flat portion 51. And an extension part 53 for use. The lower edge of each taper portion 52 serves as a paste scraping portion 54. Shafts 56 are fixed at a plurality of locations on the vertical bent portions 55 at the tips of the respective roller attachment extensions 53, and guide rollers 57 that abut the upper surface of the screen frame 12 are rotatably attached to the shafts 56. Has been. A pair of roller mounting plates 58 are pivotally attached to each roller mounting extension 53 by pins 59, and guide rollers 60 abutting on the inner surface of the screen frame 12 are pivotally attached to the roller mounting plates 58 by pins 61. It is worn. The pair of roller mounting plates 53 are mutually pulled by an extension spring 62, and the guide roller 60 is pressed against the inner surface of the screen frame. Each guide roller 57, 60
Thus, the paste cover 50 is supported so as to be able to move smoothly in the X direction with respect to the screen frame 12 without rattling. The stopper 63 protruding from the lower surface of the roller mounting extension 53 defines the moving range of the roller mounting plate 58. A cover side engaging member 70 that functions as an engaging portion for the squeegee 1 side is fixed to the upper surface of the flat portion of the paste cover 50. The cover-side engaging member has two longitudinal engaging grooves 71 and a concave groove 72 orthogonal to this. On the other hand, on the side surface of the squeegee holder 32 in which the squeegee 1 is fixedly integrated, a plate-like clamper 75 that fits in the longitudinal engagement groove 71 is provided with screws 76.
Mounted parallel to. The plate-shaped clamper 75 integrally has a spacer portion 78 that defines the minimum distance between the plate-shaped clamper 75 and the squeegee holder 32, and the plate-shaped clamper 75 is slidable with respect to the screw 76, and the head of the screw 76. The spacer 76 is pushed by the compression spring 77 disposed between the squeegee holder 32 and the clamper 75. The concave groove 72 of the cover side engaging member 70 is a screw 76.
It is formed in order to avoid the head portion and the spacer portion 78. If the paste cover 50 is provided on the screen frame 12 so as to have a predetermined positional relationship with the squeegee 1, the squeegee-side clamper 75 causes the paste cover-side engaging member 70 as shown in FIG.
By pressing the clamper 75 and the engaging member 70 fitted thereto with the compression spring 77 toward the squeegee holder side, the paste scraping portion 54 at the end edge of the paste cover 50 is Press against the side surface of the squeegee 1.
That is, the clamper 75, the compression spring 77, the engaging member 7
0 and the like constitute a pressure contact mechanism (spring mechanism) for pressing the paste scraping portion 54 against the side surface of the squeegee. In the configuration of the above embodiment, after setting one squeegee 1 in the correct positional relationship with respect to the paste cover 50, the squeegee holder 32 in FIG. 1 is driven downward to drive one (right) squeegee as shown in FIG. 1 is lowered, the tip of the squeegee 1 is pasted with the paste cover 5 as shown by the phantom line in FIG.
The squeegee side clamper 75 is fitted into the longitudinal engagement groove 71 of the cover side engagement member 70 before contacting the edge of 0. When the clamper 75 is deeply inserted into the longitudinal engagement groove 71, the tip of the squeegee 1 contacts the printing screen 11 as shown in FIG. 5, and the side surface of the squeegee 1 is the paste on the lower edge of the paste cover 50. It is in a state of being pressed against the scraping portion 54. In the state of FIG. 5, the squeegee 1 and the paste cover 50 are in an integrated state, and
The squeegee unit 30 is driven to the left by the direction driving mechanism 31 to move the squeegee 1 to the left to apply the paste 3 such as cream solder or the like, which is supplied in advance, onto the printing screen 11 in a predetermined printing range. Screen printing of paste 3 on 20 can be performed. At this time, the paste cover 50 moves integrally with the lowered squeegee 1 and covers the upper portion of the paste 3 that moves together with the squeegee 1. When the printing operation by one of the descended (right side) squeegees 1 is completed, the squeegee 1 returns to the elevated position, but the paste cover 5 is always in the order of FIG. 6, FIG. 7 and FIG.
Since the squeegee 1 moves up while the paste scraping portion 54 of 0 is in pressure contact with the side surface of the squeegee 1, the squeegee adhering paste 3 is sufficiently removed by the paste scraping portion 54. Also, the removed paste 3 returns to the paste reservoir covered with the paste cover 50. The same applies to the case where the squeegee on the left side is lowered to perform the screen printing operation. According to the above embodiment, the following effects can be obtained. (1) The squeegee 1 does not return to the raised position while the paste 3 such as cream solder remains attached to the squeegee 1, that is, the squeegee 1 always scrapes off the paste 3 with the paste scraping portion 54 of the paste cover 50. Since it rises after being hit, the paste drops even when the squeegee 1 moves away from the original printing range, such as when the TV camera 40 in FIG. 1 is going to image the alignment mark on the printing screen 11. Therefore, consumption of the paste due to dropping of the paste to a meaningless position can be prevented. (2) It is possible to prevent the inconvenience that the paste 3 drops on the alignment mark or the print pattern of the printing screen 11 and hinders the printing operation. (3) Most of the upper portion of the paste 3 such as cream solder can be covered with the paste cover 50, and the contact with the outside air can be reduced to prevent the flux and other volatile components from scattering. (4) By providing the paste cover 50, the temperature change of the paste 3 can be suppressed, and the screen printing can be continued under a substantially constant viscosity and under substantially the same temperature condition. 9 and 10 show another embodiment of the present invention. In this case, a paste stopper 80 is further added to the paste cover 50 in order to prevent the lateral flow (spreading in the longitudinal direction of the squeegee) of the paste 3 such as cream solder.
Here, the paste cover 50 is a magnetic material such as iron, and the paste stopper 80 is formed by fixing and integrating a permanent magnet 82 to a mountain-shaped stopper plate 81 that substantially matches the cross-sectional shape of the paste cover 50. Such a paste stopper 8
It is possible to prevent the paste 3 from spreading to the outside of the stopper plate 81 by magnetically attracting 0 to the inside of the left and right ends of the paste cover 50. The distance between the paste stoppers 80 is appropriately adjusted in consideration of the width of the substrate 20 to be printed. FIG. 11 shows a paste cover 50 for the squeegee 1.
It is a modified example of the pressure contact mechanism (spring mechanism) for pressing the paste scraping portion 54 of. In the above embodiment, the compression spring is provided on the squeegee side, but in the modification of FIG. 11, the compression spring 90 is provided on the engagement member 91 side mounted on the paste cover 50. That is, the engagement member 91 is fixed to the tip of the pin 93 that penetrates the L fitting 92 fixed on the paste cover 50. Then, the engaging member 91
The compression spring 90 is arranged around the pin 93 between the rear surface of the L and the L fitting 92. An inverted L-shaped clamper 100 is fixed to a squeegee holder 32 in which the squeegee 1 is fixed and integrated. The engaging member 91 is the clamper 10.
It is formed wide so as to come into contact with 0 in a sufficiently wide area. Also in the modification of FIG. 11, the squeegee-side clamper 1
00 is engaged with the engagement member 91 on the paste cover 50 side, the paste cover 50 and the squeegee 1 are pressed by the compression spring 90.
Since and are urged toward each other, the paste scraping portion 54 at the lower end edge of the paste cover 50 comes into pressure contact with the side surface of the squeegee 1, and a similar effect of removing the squeegee adhering paste 3 is obtained.

As described above, according to the cover device for scraping off the squeegee-attached paste of the present invention, the paste such as cream solder attached to the squeegee of the screen printing machine is scraped on the paste cover. The side surface of the squeegee can be scraped off and sufficiently removed by the take-up part, and the phenomenon of dropping of the paste from the squeegee can be reliably prevented. Further, it is possible to cover the paste on the printing screen with a paste cover to reduce the contact between the paste and the outside air to prevent the scattering of flux and other volatile components, and to continue the screen printing operation under substantially the same conditions. ..

[Brief description of drawings]

FIG. 1 is a front view showing an overall configuration of an embodiment of a cover device for scraping and removing a squeegee attached paste according to the present invention.

FIG. 2 is a plan view of a paste cover which is a main part configuration of an embodiment and a portion accompanying the paste cover.

FIG. 3 is a side view of the same.

FIG. 4 is an enlarged cross-sectional view showing the configuration of the main part of the embodiment during the descent of the squeegee.

FIG. 5 is an enlarged cross-sectional view of the main part configuration of the embodiment after the squeegee is lowered.

FIG. 6 is an explanatory diagram showing a positional relationship between a squeegee and a paste cover immediately after screen printing.

FIG. 7 is an explanatory diagram showing a positional relationship between the squeegee and the paste cover at a position where the squeegee is raised after screen printing.

FIG. 8 is an explanatory diagram showing the positional relationship between the squeegee and the paste cover at the time when the squeegee has risen after screen printing and the paste scraping has ended.

FIG. 9 is a partial side view showing another embodiment of the present invention.

FIG. 10 is a front sectional view of the same.

FIG. 11 is a front cross-sectional view showing a modified example of a pressure contact mechanism (spring mechanism) that presses the paste scraping portion of the paste cover against the squeegee.

FIG. 12 is an explanatory diagram showing a conventional scraping mechanism for squeegee-deposited paste.

13 is an explanatory diagram showing an inconvenience in the case of the conventional mechanism of FIG.

FIG. 14 is an explanatory diagram showing another example of a conventional scraping mechanism for squeegee attached paste.

[Explanation of symbols]

 1 Squeegee 10 Frame of this machine 11 Screen for printing 12 Screen frame 20 Substrate 30 Squeegee unit 32 Squeegee holder 40 TV camera 50 Paste cover 54 Paste scraping part 57, 60 Guide roller 70 Cover side engaging member 75 Clamper 80 Paste stopper

Claims (1)

[Claims] 1. A squeegee comprising a paste cover movably provided with respect to a screen frame, an engaging portion provided on the paste cover and engaging with a squeegee side, and a paste scraping portion of the paste cover. A cover device that also serves as a scraper for squeegee-deposited paste, characterized in that the cover device is provided with a pressure contact mechanism for pressing the side surface of the contact part.