GB2121725A - Inker apparatus - Google Patents

Abstract

Coating apparatus 10 constructed primarily for the application of high viscosity paste-type ink includes cellular fountain roll 11 whose outer cylindrical surface extends into a pool of coating material disposed within a trough 17. A doctor blade 30 biased against the cylindrical surface removes excess material from the fountain roll and forms a film that is of final usable thickness. A flow control shield 50 disposed within the trough 17 and positioned upstream of the doctor blade 30 is provided with a concave front surface that faces the cylindrical surface of the fountain roll 10 in close spaced relationship therewith. The shield 50 and cylindrical surface of roll 11 co-operate to define a space of gradually diminishing thickness measured in a downstream direction, which acts to force coating material into the open cells of the cylindrical surface of roll 11. <IMAGE>

Description

SPECIFICATION Inker apparatus U.S. Patent No. 3,645,201, discloses apparatus in which objects to be decorated are carried by mandrels that extend radially from a turret. The latter is moved in angular steps so that each of these objects is carried to and stopped for short intervals at a plurality of decorating stations and drying stations, with a drying station being disposed immediately downstream of each of the decorating stations. At each decorating station a decoration is applied to the object and this decoration is air dried at the next drying station. During high speed operation, even though the objects are stopped at each decorating and drying station for only a short time, satisfactory air drying is obtained because a high solvent or low viscosity ink is used.However, this type of ink requires extra preparations which are not required when utilizing high viscosity paste-type ink, typically a type which is cured by ultra-violet radiation.

That is, since a low viscosity, high solvent flexo ink dries so rapidly, it cannot be permitted to remain overnight in the decorating apparatus. Further, on start-up, results are not reasonably predictable insofar as drying time and adhesive properties. In contrast, high viscosity paste-type ink may remain in the decorating apparatus overnight or even for days without adverse results, and on start-up results are readily predictable.

The inker apparatus of U.S. Patent No. 4,244,292 is especially adapted for use in a process decorator of the type described generally in the aforesaid U.S.

Patent No. 3,645,201 when paste-type inks are utilized. In particular the apparatus of U.S. Patent No.

4,244,292 utilizes a wiper to force ink into the cavities of an aniloxtype fountain roll and then utilizes a scraper-type doctor blade for metering purposes.

Since the wiper blade is baised into engagement with the roughened surface of the rotating anilox roll, one or both of these elements is caused to wear relatively rapidly. Further, because the wiper blade is in contact with the anilox roll, when ink of especially high viscosity is utilized, fluid pressure may become so high that the wiper blade is damaged. In order to overcome the aforesaid disadvantages of the prior art, the instant invention replaces the wiper blade of the aforesaid U.S. Patent No. 4,244,292 by a flow control shield that does not contact the surface of the anilox fountain roll. This shield is an elongated curved element whose concave surface faces the cylindrical outer surface of the fountain roll and whose outer convex surface faces and is spaced from the curved inner surface of the ink trough.The shield and the fountain roll co-operate to define a space of gradually diminishing thickness in a downstream direction, which serves to force or drive ink into the cavities of the fountain roll. The space behind the shield provides a passage through which ink is permitted to recirculate in an upstream direction.

Coating apparatus according to the invention includes a trough that may contain a pool of coating material, a rotationally mounted fountain roll extending into the trough such that it may extend into the pool, a doctor means positioned to engage a film of coating material on the outer cylindrical surface of the roll, and a flow control shield that is upstream of the doctor means and within the trough, and has a front surface that faces the cylindrical surface and is free from contact therewith, and in which the said front surface and the cylindrical surface co-operate to define a space of gradually diminishing thickness measured in a downstream direction to force coating material toward the cylindrical surface.

The front surface of the flow control shield preferably is concaved. The rear surface of the shield is generally spaced from the interior surface of the trough. Typically the rear surface is convexed and the interior surface of the trough is concaved.

The shield may be constructed of relatively stiff resilient material.

The downstream edge of the shield is generally disposed at the region where the doctor means is adjacent to the cylindrical surface, that is to say where it engages the coating film on the cylindrical surface. The doctor means generally comprises a scraper blade that may be biased against the surface in conventional manner. The working edge of the scraper blade normally extends parallel to the rotationally axis of the fountain roll, and is in contact with the cylindrical surface at a position about 15 upstream of the horizontal position. Thus when the fountain roll is viewed end on, and is rotating counter clockwise the scraper blade is at a position of approximately 3:30 measured on the clock.

The apparatus is of particular value when the coating material is an ink.

The invention is now described with reference to the accompanying drawings. Figure 7 is an end view of coating apparatus constructed in accordance with teachings of the instant invention, shown in operative relationship with a plate cylinder and a container to be decorated.

Figure 2 is an enlarged end view of the coating apparatus of Figure 1.

Figure 3 is a fragmentary elevation looking in the direction of arrows 3-3 of Figure 2.

Figure 4 is a fragmentary cross-section taken through line 4-4 of Figure 1 looking in the direction of arrows 4-4.

Figures 5 and 6 are side elevations of the coating apparatus looking in the directions of the respective arrows 5-5 and 6-6 of Figure 2.

Figure 7 is a plan view of the coating apparatus looking in the direction of arrows 7-7 of Figure 5.

Coating apparatus 10 is utilized for decorating cylindrical container 15 by having anilox-typefountain roll 11 keyed to rotating shaft 12 apply coating material, usually a high viscosity paste-type ink, to printing plate 14 on rotatable plate cylinder 13, with plate 14 engaging the outer surface of container 15 that is rotating in co-ordination with the rotation of plate roll 13.

Apparatus 10 also includes elongated block 16 that co-operates with auxiliary wall member 26 to define an upwardly facing trough 17 whose ends are closed by plates 18,19. The rear or bottom of block 16 is provided with rectangular cutout 21 (Figure 2) which receives the generally horizontal leg of L-shaped base 20. Pins 22 extend into base plate slot 23 to permit limited lengthwise adjustment of block 16 on base plate 20. Clamping screw 24 at the side of block 16 opposite pins 22 clamp block 16 to base 20.

Auxiliary side member 26 is secured to block 16 by three bolts 27. Mounted along the upper edge 28 of auxiliary side member 26 is scraper blade 30 whose free end engages the outer cylindrical surface of anilox type fountain roll 11. Blade 30 is held against side member 26 by clamping strip 31 which is secured to L-shaped mounting member 32 by screws 33. A plurality of pins 34 biased outwardly from recesses in the upper edge 28 urge mounting member 32 upward. This motion is counteracted by retaining screws 35 that are threaded into edge 28.

Spring 36 interposed between the head of screw 35 and mounting member 32 biases the latter downward. Thumb screw 37 threadably extends through one leg of mounting member 32 to clamp that leg to auxiliary side member 26. Portions of shaft 12 at opposite ends of fountain roll 11 are supported in semi-circular bearing notches cut in the upper surfaces of end walls 18, 19 and one end of shaft 12 extends into a circular recess in the upright portion of base 20.

Annular notches 41 in the cylindrical surface of fountain roll 11 form portions of labyrinth seals at opposite ends of the trough 17, co-operating with complementary formations in portions of end walls 18,19.

Disposed within trough 17 and positioned behind roll 11 is curved flow control shield 50 constructed of relatively stiff spring material. Spaced standoffs 51 extending forward from the rear of shield 50 are provided with threaded apertures that receive screws 52 extending through the rear of block 16 to operatively secure shield 50. The concave upper surface of shield 50 faces the cylindrical surface of fountain roll 11 and the downstream end of shield 50 is disposed in the region where scraper blade 30 engages roll 11. Disposed within trough 17 and positioned slightly upstream of shield 50 is splash strip 55 which is mounted to block 16 by screws 56.

Shield 50 co-operates with the cylindrical surface of fountain roll 11 to form a curved wedge-like passage for ink or other coating material, with the narrow end of the wedge being positioned downstream of the wide end of the wedge. This forces the coating material into the surface recesses of roll 11, yet excessive pressure build-up acting against shield 50 is prevented in that the latter does not contact roll 11 and there is sufficient clearance between roll 11 and shield 50 at the downstream end of the latter.

Claims (10)

1. Coating apparatus including a trough that may contain a pool of coating material, a rotationally mounted fountain roll extending into the trough such that it may extend into the pool of coating material, a doctor means positioned to engage a film of coating material on the outer cylindrical surface of the roll and a flow control shield that is upstream of the doctor means and is within the trough and has a front surface facing the cylindrical surface and free from contact therewith, and in which the front surface and the cylindrical surface co-operate to define a space of gradually diminishing thickness measured in a downstream direction to force coating material toward the cylindrical surface.

2. Coating apparatus as set forth in Claim 1 in which the front surface is concave.

3. Coating apparatus as set forth in Claim 2 in which the downstream edge of said shield is disposed at the region where the doctor means is adjacent said cylindrical surface.

4. Coating apparatus as set forth in Claim 2 or 3 in which the rear surface of said shield is spaced from the interior surface of said trough.

5. Coating apparatus as set forth in Claim 4 in which the shield is constructed of relatively stiff resilient material.

6. Coating apparatus as set forth in Claim 5 in which the doctor means comprises a scraper blade.

7. Coating apparatus as set forth in Claim 6 in which the working edge of the scraper blade extends parallel to the rotational axis of the fountain roll and is in contact with the cylindrical surface at a position of approximately 15 below and upstream of the horizontal position.

8. Coating apparatus as set forth in Claim 6 in which the rear surface of the shield is convex and the interior surface of the trough is concave.

9. A coating apparatus according to any preceding claim containing a pool of coating material in the trough.

10. A coating apparatus substantially as herein described with reference to the accompanying drawings.