GB2476682A

GB2476682A - Screen printing apparatus for printing on substantially frusto conical articles

Info

Publication number: GB2476682A
Application number: GB201000076A
Authority: GB
Inventors: Christopher Owen
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-01-05
Filing date: 2010-01-05
Publication date: 2011-07-06
Anticipated expiration: 2030-01-05
Also published as: GB201000076D0; GB2476682B

Abstract

Screen printing apparatus 30 for printing on substantially frusto conical articles such as a glass 32. The apparatus 30 includes a holding arrangement 34 for holding a glass 32 such that the surface to be decorated extends horizontally. A mounting arrangement 54 mounts a screen printing frame 56. The apparatus is arranged such that the frame 56 is moved past the glass 32 as the glass 32 is rotated, with the frame 56 being movable in an arcuate path substantially about the apex of the cone of the frusto conical glass 32.

Description

Screen Printing Apparatus This invention concerns screen printing apparatus, and particularly but not exclusively apparatus for screen printing frusto conical articles.

In screen printing items of hollowware such as mugs or glasses, an ink covered screen is moved across the article as the article is simultaneously rotated, so as to transfer a pattern around the article. The screen may be an emulsion covered nylon mesh, which has been exposed photographically to remove the emulsion where colour is required to be printed.

Fig. 1 shows a typical apparatus for screen printing hollow articles such as a straight sided glass 10. The glass 10 is selectively held on a holding arrangement 12 by suction. The holding arrangement 12 is freely rotatable and is coaxial with a gear 14. A toothed rack 16 is provided which is engageable with the gear 14, and the rack 16 is mounted to a pneumatic cylinder 18.

A screen printing frame 20 is provided which is movable over the glass 10 to print ink thereon. A squeegee blade 22 extends into the frame 20. The frame 20 is powered to move in a horizontal direction, and as the frame 20 is moved the rack 16 simultaneously rotates the holding arrangement 12 and hence glass 10.

Fig. 2 shows the apparatus of Fig. 1 but being used to print on a glass 24 with a frusto conical body. In this instance the frame 20 is mounted at an inclination so as to be substantially parallel to the frusto conical sides of the glass 24. When used in this configuration there is a mismatch of surface speeds between the frame 20 and sides of the glass 24 along the length thereof, due to the differing diameters of the glass 24 at the lower and upper ends thereof.

The different relative speeds mean that there is skidding between the frame 20 and glass 24 leading to distorted and unclear images with poor clarity and sharpness at the top and bottom of the glass 24. Also as the frame is inclined, ink tends to flow to the lower part of the frame 20. This will then require more ink to be loaded into the frame 20 and/or the apparatus to be stopped and the ink to be moved manually to a higher part of the frame 20.

According to the present invention there is provided screen printing apparatus for printing on substantially frusto conical articles, the apparatus including: a holding arrangement for selectively mounting an article to be printed; a rotating arrangement for selectively rotating the mounting arrangement; a mounting arrangement for mounting a screen printing frame; and a moving arrangement for moving the mounting arrangement past the holding arrangement as the latter is turned by the rotating arrangement, so as to print on an article on the mounting arrangement; the moving arrangement being configured to be movable in an arcuate path substantially about the apex of the cone of a frusto conical article on the mounting arrangement.

The holding arrangement may have a reduced pressure system such that an article can be held thereon by suction.

The holding arrangement may be configured such that an article can be held thereon with the surface of the article to be decorated being aligned substantially horizontally. The inclination of the holding arrangement may be

adjustable.

A drive means may be provided, which may be in the form of a pneumatic cylinder. Alternatively, the drive means may be in the form of an electrical motor or an electrical servo motor.

The drive means may actuate the rotating arrangement. A toothed rack on the drive means may be engageable with a gear on the rotating arrangement. The rotating arrangement gear may be substantially co-circumferential with the cone of a frusto conical article on the mounting arrangement.

The position of the holding arrangement relative to the rotating arrangement gear may be adjustable such that the rotating arrangement gear can be substantially co-circumferential with the cone of different frusto conical articles on the mounting arrangement.

The mounting arrangement may be configured to mount a screen printing frame substantially horizontally.

The moving arrangement may move the mounting arrangement in a substantially horizontal arcuate path.

The moving arrangement may be actuable by the drive means.

The moving arrangement may include an arcuate toothed rack, which toothed rack may be engageable with a straight toothed rack on the moving arrangement.

The relative position of the mounting arrangement may be adjustable.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:-Fig. 1 is a diagrammatic side view of an existing screen printing apparatus being used to print on a cylindrical article; Fig. 2 is a similar view to Fig. 1 but with the apparatus being used to decorate a frusto conical article; Fig. 3 is a similar view to Fig. 1 but of a screen printing apparatus according to the invention; Fig. 4 is a diagrammatic plan view of part of the apparatus of Fig. 1; and Fig. 5 is a diagrammatic side view of a third part of the apparatus of Fig. 3.

Figs. 3 to 5 show screen printing apparatus 30 which is similar in many respects to the apparatus described in relation to Figs. 1 and 2, and therefore only the differences will be discussed. The apparatus 30 is shown decorating a glass 32 similar to the glass 24. The glass 32 is held on a holding arrangement 34 which in this instance can be selectively aligned at different inclinations by virtue of an adjustable bearing housing 36.

As shown the holding arrangement 34 is inclined such that the surface of the glass 32 to be decorated is extending substantially horizontally. The holding arrangement 34 includes a reduced pressure arrangement 38 which can hold the glass 32 thereon by suction. The reduced pressure arrangement 38 is provided on the free end of an arm 40 of adjustable length. Provided between the arm 40 and the bearing housing 36 a shaft 42 mounts a gear 44.

The gear 44 is mounted to a slot 46 in the shaft 42 such that the relative position thereof can be adjusted.

The apparatus 30 includes a pneumatic cylinder 48 with a movable straight toothed rack 50 which is engageable with the gear 44 to cause rotation thereof.

The apparatus 30 also includes an arcuate upward facing toothed rack 52 which is mounted to a mounting arrangement 54 for a screen printing frame 56. The toothed rack 52 is engageable with a further straight toothed rack 58 connected to the cylinder 48, such that movement of the cylinder 48 causes arcuate movement of the frame 56.

In use the apparatus 30 can be configured as follows. The length of the arm 40 is adjusted such that the apex of a cone of the frusto conical sides of the glass 32 is coaxial with the axis of the arcuate rack 52 and this axis is shown at 60 on Fig. 4. The position of the gear 44 is adjusted on the shaft 42 such that the gear is co-circumferential with the cone of the frusto conical sides of the glass 32 as shown by the dotted lines 62 in Fig. 5.

Therefore in use, when the cylinder 48 is actuated this causes the glass 32 to be rotated by the holding arrangement 34, and the screen frame 56 to be moved over the glass 32 in an arcuate direction, such that the surface speeds between the frame 50 and glass 32 are substantially equal across the height of the glass. This leads to a sharp and clear print along the height of the glass 32. The image to be printed by the screen frame 56 is shown at 64.

There is thus described an apparatus for screen printing frusto conical items such as glasses or mugs with tapering sides whilst providing for accurate and sharp printing by virtue of the matched surface speeds of the printing screen and surface of the article. The apparatus operates in a similar manner to existing apparatus and can thus be used in a similar way by correspondingly trained operatives.

In this instance the printing screen is retained in a horizontal alignment, thereby not encountering the problems outlined above when using inclined screen frames. The apparatus can readily be adjusted for different degrees of tapering on articles, whilst maintaining the advantages outlined above.

A number of modifications may be made without departing from the scope of the invention. For instance, different methods could be used to provide the respective relative movements. Drive means other than pneumatic cylinders could be used, and for example electric or electrical servo motors could be used.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims 1. Screen printing apparatus for printing on substantially frusto conical articles, the apparatus including: a mounting arrangement for mounting a screen printing frame; a holding arrangement for selectively mounting an article to be printed; a rotating arrangement for selectively rotating the mounting arrangement; and a moving arrangement for moving the mounting arrangement past the holding arrangement as the latter is turned by the rotating arrangement, so as to print on an article on the mounting arrangement; the moving arrangement being configured to be movable in an arcuate path substantially about the apex of the cone of a frusto conical article on the mounting arrangement.
2. Apparatus according to claim 1, in which the holding arrangement has a reduced pressure system such that an article can be held thereon by suction.S
3. Apparatus according to claims 1 or 2, in which the holding arrangement is configured such that an article can be held thereon with the surface of the article to be decorated being aligned substantially horizontally.
4. Apparatus according to any of the preceding claims, in which the inclination of the holding arrangement is adjustable.
5. Apparatus according to any of the preceding claims, in which a drive means is provided.
6. Apparatus according to claim 5, in which the drive means is in the form of a pneumatic cylinder.
7. Apparatus according to claim 5, in which the drive means is in the form of an electrical motor.
8. Apparatus according to claim 5, in which the drive means is in the form of an electrical servo motor.
9. Apparatus according to any of claims 5 to 8, in which the drive means actuates the rotating arrangement.
10. Apparatus according to claim 9, in which a toothed rack on the drive means is engageable with a gear on the rotating arrangement.
11. Apparatus according to claim 10, in which the rotating arrangement gear is substantially co-circumferential with the cone of a frusto conical article on the mounting arrangement.
12. Apparatus according to claim 11, in which the position of the holding arrangement re'ative to the rotating arrangement gear is adjustable such that * the rotating arrangement gear can be substantially co-circumferential with the cone of different frusto conical articles on the mounting arrangement.S **.S
13. Apparatus according to any of the preceding claims, in which the mounting arrangement is configured to mount a screen printing frame *: * . substantially horizontally.
14. Apparatus according to any of the preceding claims, in which the moving arrangement moves the mounting arrangement in a substantially horizontal arcuate path.
15. Apparatus according to claim 5 or any claim dependent thereon, in which the moving arrangement is actuable by the drive means.
16. Apparatus according to any of the preceding claims, in which the moving arrangement includes an arcuate toothed rack.
17. Apparatus according to claim 16 when dependent on claim 5, in which the arcuate toothed rack is engageable with a straight toothed rack connected to the drive means.
18. Apparatus according to any of the preceding claims, which the relative position of the mounting arrangement is adjustable.
19. Screen printing apparatus substantially as hereinbefore described and with reference to the drawings.
20. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.***. 15 *..S * S. .5. * S * * S S S.. S * IS.S S. * S * .c' S. * * . . S *SAmendments to the claims have been filed as follows Claims 1. Screen printing apparatus for printing on substantially frusto conical articles, the apparatus including: a mounting arrangement for mounting a screen printing frame; a holding arrangement for selectively mounting an article to be printed; a rotating arrangement for selectively rotating the holding arrangement; and a moving arrangement for moving the mounting arrangement past the holding arrangement as the latter is turned by the rotating arrangement, so as to print on an article on the holding arrangement; the moving arrangement being configured to be movable in an arcuate path substantially about the apex of the cone of a frusto conical article on the mounting arrangement, wherein the holding arrangement comprises an adjustable length arm and the rotating arrangement includes a gear located on a shaft, the position of the gear being adjustable on the shaft such that the gear can be substantially co-circumferential with the cone of different frusto *....: conical articles on the holding arrangement.2. Apparatus according to claim 1, in which the holding arrangement has a reduced pressure system such that an article can be held thereon by suction.* .. 20 * 4 * **** * 3. Apparatus according to claims 1 or 2, in which the holding arrangement is configured such that an article can be held thereon with the surface of the article to be decorated being aligned substantially horizontally.4. Apparatus according to any of the preceding claims, in which the inclination of the holding arrangement is adjustable.5. Apparatus according to any of the preceding claims, in which a drive means is provided.6. Apparatus according to claim 5, in which the drive means is in the form of a pneumatic cylinder.7. Apparatus according to claim 5, in which the drive means is in the form of an electrical motor.8. Apparatus according to claim 5, in which the drive means is in the form of an electrical servo motor.9. Apparatus according to any of claims 5 to 8, in which the drive means actuates the rotating arrangement.10. Apparatus according to claim 9, in which a toothed rack on the drive means is engageable with the gear on the rotating arrangement.11. Apparatus according to any of the preceding claims, in which the mounting arrangement is configured to mount a screen printing frame * : *.: substantia'ly horizontally.: 12. Apparatus according to any of the preceding claims, in which the moving arrangement moves the mounting arrangement in a substantially : *. 20 horizontal arcuate path. * **.13. Apparatus according to any of the preceding claims, in which the moving arrangement is actuable by the drive means.14. Apparatus according to any of the preceding claims, in which the moving arrangement includes an arcuate toothed rack.15. Apparatus according to claim 14 in which the arcuate toothed rack is engageable with a straight toothed rack connected to the drive means.16. Apparatus according to any of the preceding claims, in which the relative position of the mounting arrangement is adjustable.17. Screen printing apparatus substantially as hereinbefore described and with reference to the drawings.S * SS *.*.. * S *� * S. *5 S 55*5 *05S