GB2313428A

GB2313428A - Roller for a printing machine

Info

Publication number: GB2313428A
Application number: GB9710140A
Authority: GB
Inventors: Stefan Menzinger; Peer Dilling
Original assignee: MAN Roland Druckmaschinen AG
Current assignee: Manroland AG
Priority date: 1996-05-20
Filing date: 1997-05-19
Publication date: 1997-11-26
Also published as: DE29609007U1; FR2748688B1; FR2748688A1; GB9710140D0

Abstract

A roller 1 for a printing machine comprises a hollow core in the form of a cylindrical sleeve 21 and a coating 22 of a fibre-composite material applied directly to the outer casing surface of the core. The sleeve 21 is rotatably mounted on a shaft 2 via bearings 13, 14. This roller is easy to manufacture and preserves the advantages of a lightweight construction.

Description

Roller for a printing machine The invention relates to a roller for a printing machine having a hollow core, such as one formed from a steel tube.

A device for producing printing unit rollers for rotary printing machines is already known from DE 24 18 599 Al. The known printing unit rollers, for instance paper guide rollers, have thin walls which have to comply with the strict requirements regarding centricity and straightness. They are produced by inserting a steel tube into a mould having a cylindrical inner chamber, its inner diameter, which corresponds to the desired outer diameter of the roller, being somewhat greater than the diameter of the tube. The tube is then plastically deformed beyond the elastic limit of its material by introducing a pressure medium. During this working procedure, the tube material can flow to the inner contour of the mould, thus reducing uneven stresses in the tube and producing a new stress field distributed uniformly over the entire length, all of which ensures the accurate vibration-free centricity of the roller.

It is already known for rollers of this type, having an inner chamber, to be provided with a coating of a carbon-fibre-reinforced plastics material on their casing surface. First of all, many layers of the carbon-fibre-reinforced plastics are wound onto a separate wound core, thus producing a coating. The wound core is then removed from the sleeve of carbonreinforced plastics surrounding it. The sleeve is then drawn over the roller with the hollow chamber and secured to it by means of an adhesive.

This process is time-consuming and expensive as it is necessary to provide a wound core for the production of the sleeve from the carbon-fibre-reinforced plastics and to remove the sleeve from the wound core. The sticking process also requires a lot of time.

It is the aim of the invention to improve a roller of the above type so that it can be produced more easily and more economically.

This aim is achieved as described in claims 1 and 9. With the invention the composite material coating is formed directly on the roller core.

Preferred embodiments can be seen in the sub-claims.

An embodiment of the invention is described below by way of example with reference to the single attached Figure.

The Figure shows a roller 1 which is rotatably mounted on a fixed spindle or shaft 2. In use the shaft 2 is held at each end by a roller lock 3, 4. The roller locks 3, 4 allow the roller 1 to be taken out of the printing machine for repair or replacement. The roller locks 3, 4 are each secured on plates 5 or 6, which in turn are fitted pivotably to the inside of the side walls 7, 8 of the printing machine. In order to remove the roller 1 from the printing machine, protective caps 9, 10 are removed from the roller locks 3 and 4, so that the screws 11, 12 that hold the shaft 2 in the roller locks 3, 4 can be screwed off the stub ends of the shaft 2.

The roller 1 is rotatably mounted on the shaft 2 by means of roller bearings 13, 14, one near each end.

The roller bearings 13, 14 are held on their outer side by hollow rings 15, 16 which at the same time form the roller bases. The rings 15, 16 each have a groove 17, 18 on their outer surfaces of revolution. The grooves 17, 18 receive corresponding corrugations or indentations 19, 20 in a sleeve 21 of steel supported by the rings. The sleeve 21 is covered on its outer casing surface, i.e. its radially outer surface, by a layer 22 of a fibre composite material. The corrugations 19, 20 in the sleeve prevent the layer 22 from moving in the direction of the longitudinal axis of the roller 1.

During the production of the corrugations there also arise unevennesses in the outer casing surfaces of the sleeve 21 in the axial direction, which prevent the layer 22 also from moving in the circumferential direction of the roller 2. The layer 22 thus has a fixed, positive-locking connection with the sleeve 21.

The layer 22 of a fibre composite material, for instance of carbon-fibre-reinforced plastics, is applied to the assembly of the sleeve 21 and the hollow rings 15, 16 by fixing the assembly on a shaft and winding a resin-saturated bundle of threads of the plastics onto the sleeve 21 by rotation of the shaft until the desired layer thickness is achieved.

If the roller 1 is a dampening or ink-transferring roller in a dampening or inking unit, the layer 22 is further covered by a rubber or plastics layer 23 which complies with the required properties for transfer of the dampening agent or the printing ink.

Without a rubber or plastics layer 23, a roller of the same type as roller 1 is suitable also as a swinging roller, measurement roller, feed roller or web guide roller in a printing machine. It is characterised by its light weight so that it can be easily replaced. Since the inside of the roller 1 is hollow, and the layer 22 has only a small mass because of the low density of the fibre composite material, the roller 1 also has a low moment of inertia so that it can be quickly accelerated and slowed down.

The roller 1 thus produced can be driven over its casing surface by friction with other rollers or with the printing material web. The roller 1 is characterised by its light weight and its low moment of inertia. It is arranged on a rigid shaft 2 by means of roller bearings 13, 14. The roller bearings 13, 14 carry hollow rings 15, 16 which in turn carry a sleeve 21 of steel. The sleeve 21 is covered by a layer 22 of a fibre composite material, located on the sleeve 21 in a positive-locking manner.

Claims

Claims 1, A roller (1) for a printing machine, comprising a hollow core (21) and a coating (22) of a fibre composite material on the outer casing surface of the core.
2. A roller (1) according to claim 1, in which the core is formed from a steel sleeve (21).
3. A roller (1) according to claim 1 or 2, in which the coating (22) has a positive-locking connection with the sleeve (21).
4. A roller (1) according to claim 3, in which the positive-locking connection is produced by grooves or corrugations in the sleeve (21) and corresponding shaping of the coating.
5. A roller (1) according to any preceding claim, in which the fibre composite material is a carbon-fibre-reinforced plastics material.
6. A roller (1) according to any preceding claim and having a rubber or plastics coating (23) on the fibre-composite coating (22).
7. A roller assembly including a hollow roller as claimed in any preceding claim rotatably mounted on a shaft (2) passing through the roller.
8. A printing machine including a roller assembly as in claim 7 detachably mounted between two side walls.
9. A method of making a roller for a printing machine, in which a hollow cylindrical core is coated with a composite material, which then sets or hardens on the core.
10. A roller assembly according to claim 9, in which the coating is effected by winding impregnated fibres on to the core until the required thickness is attained.