Device and method for positioning a substrate to be printed

• US 20050166772A1
• Filed: 05/16/2003
• Published: 08/04/2005
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Asys Automatisierungssysteme GmbH
• Original Assignee: Asys Automatisierungssysteme GmbH
• Inventors: Schanz, Karl
• Granted Patent: US 7,225,734 B2
• Time in Patent Office: Days
• US Class Current: 101/126
• CPC Class Codes: B41F 15/16 Printing tables
• CPC Class Codes: B41P 2215/11 Registering devices

Abstract

The invention relates to a device and a method for positioning a substrate (4) to be printed in accordance with the screen printing method, lying on a print table (2), with respect to the template of the screen (3) of the screen printing device. After placement and fixing of the substrate (4) on the print table (2), and with the screen (3) arranged close to the print position, the side of the screen (3) towards the print table (3) is illuminated from the print table (2) and least one predetermined edge section (6) of the substrate (4) is photoelectrically detected from the print table (2). After evaluation of the detection signals, the screen (3) is adjusted into its desired disposition with respect to the actual disposition of the substrate (4), and then the printing is effected.

Claims

1. Device for positioning a substrate (4) to be printed in accordance with a screen printing process, lying on a print table (2), with respect to the print template of the screen (3) of the screen printing device,

having a transportation and placement arrangement for delivering a substrate (4) to be printed, placing and fixing thereof on the print table (2) and transportation away of the printed substrate (4),

having a photoelectric arrangement (8) for detecting the actual disposition of the substrate (4) placed on the print table (2) and for generating corresponding adjustment signals, and

having an adjustment device for adjusting the relative disposition of the screen (3) and therewith of the print template with respect to the print table (2) and therewith the substrate (4) in dependence upon the adjustment signals corresponding to the desired disposition, provided for printing, of the substrate (4) on the print table (2) with respect to the print template of the screen (3),

characterized in that,

an illumination arrangement (7) is so arranged that it illuminates the screen (3), in a raised position, which % slight spacing from the placed substrate (4), from the print table (2) side, and

in that the photoelectric arrangement (8) is so configured and arranged that it detects the light diffusely reflected from the screen (3) in the region of predetermined edge sections (6) of the placed substrate (4), evaluates this detected light with regard to the actual disposition of the edge of the substrate (4) and derives therefrom the adjustment signals and delivers them to the adjustment device.

2. Device according to claim 1,

characterized in that,

the print table (2) is constituted to be light permeable in the region of the illumination device (7) and in the region of the photoelectric arrangement (8), the illumination arrangement (7) and the photoelectric arrangement (8) being arranged in or below the print table (2) in the respective region concerned.

3. Device according to claim 2,

characterized in that,

the light permeable constitution is formed in each case by means of an embedded acrylic glass or glass insert (13, 15).

4. Device according to claim 2 or 3,

characterized in that,

the light permeable region of the illumination arrangement (7) and the light permeable region of the photoelectric arrangement (8) are separated (16) from one another.

5. Device according to any of claims 2 to 4,

characterized in that,

the light permeable region of the illumination arrangement (7) substantially concentrically surrounds the light permeable region of the photoelectric arrangement (8).

6. Device according to any of claims 1 to 5,

characterized in that,

the illumination arrangement is formed by means of LEDs (14).

7. Device according to any of claims 2 to 6,

characterized in that,

the light permeable region of the illumination arrangement contains mirror surfaces (17) which deflect the emitted light onto a region of the screen (3) lying opposite to the associated photoelectric arrangement (8).

8. Device according to any of claims 1 to 7,

characterized in that,

the photoelectric arrangement is formed by means of a CCD imaging apparatus (8).

9. Method for positioning a substrate (4), to be printed in accordance with the screen printing method, lying on a print table (2), with respect to the print template of the screen (3) of a screen printing device, having steps for

adjusting the relative disposition of the screen (3) and of the substrate (4) with regard to the desired position, wished for the printing, in dependence upon the detection of the actual disposition,

in advance, placing and fixing the substrate (4) on the print table in a position approximately corresponding to the desired printing position detection of the actual disposition of the substrate (4) placed on the print table (2) at at least one predetermined edge section (6) of the substrate (4) by photoelectric measures,

characterized by

further steps for bringing the screen (3) into its print position with respect to the print table (2) with a still slighter spacing to the substrate (4),

illumination of the side of the screen (3) towards the print table (2) from the region of the print table (2) in which the predetermined edge section (6) of the substrate (4) has been placed,

detection of the actual disposition of the observed predetermined edge section (6) of the substrate (4) by means of a fixedly arranged photoelectric detector (8) such that this receives light diffusely reflected from the screen (3) in the region of the observed predetermined edge section (6), and

adjustment of print table (2) and screen (3) with respect to one another such that the print template of the screen (3) is positioned in its desired disposition with respect to the substrate (4) in its actual disposition.

10. Method according to claim 9,

characterized by

the determination of the relative disposition of the substrate (4) on the print table (2) with respect to the print template of the screen (3) by means of three predetermined edge sections (6) distributed over the edge of the substrate (4).

11. Method according to claim 9 or 10,

characterized in that,

while maintaining the slight spacing of the screen (3) with respect to the substrate (4), the screen (3) is adjusted (9, 10, 11), in the corresponding closely neighboring plane parallel to the actual printing disposition, into the printing desired disposition with respect to the substrate (4) in its actual disposition, and only then is brought (20) into the printing disposition for printing of the substrate (4).