GB2366243A

GB2366243A - A flexographic printing cartridge

Info

Publication number: GB2366243A
Application number: GB0021558A
Authority: GB
Inventors: Andrew Steven
Original assignee: CRABTREE GATESHEAD Ltd; Crabtree of Gateshead Ltd
Current assignee: CRABTREE GATESHEAD Ltd; Crabtree of Gateshead Ltd
Priority date: 2000-09-02
Filing date: 2000-09-02
Publication date: 2002-03-06
Anticipated expiration: 2020-09-02
Also published as: GB2366243B; GB0021558D0

Abstract

Flexographic printing cartridges which fit interchangeably in the print towers 10 of printing machines house an ink reservoir 14 adapted to spread a very thin coating of ink evenly over the periphery of an inking cylinder which makes rolling contact with a bas-relief patterned resilient printing plate 22 carried on the periphery of a printing cylinder. The printing cylinder can make rolling contact with the periphery of an impression cylinder journalled in the machine so as to be capable of printing on a substrate fed through the nip between the printing cylinder and the impression cylinder. Different cartridges have been required for different sizes of printing plates. By positioning the axis of a printing cylinder 20 along a locus 28, interchangeable printing cylinders of different diameters carrying printing plates of corresponding sizes can be accommodated in peripheral contact with the inking cylinder 16 and the impression cylinder 24 without the need to change the whole cartridge 12. The sole drawing should accompany the abstract.

Description

<Desc/Clms Page number 1> "A Flexoqraphi,c Printing Cartridge." This invention relates to a flexographic printing cartridge for a print tower for a printing machine.

Interchangeable flexographic printing cartridges are already known. They contain an ink reservoir usually referred to as a doctoring chamber into which there extends an arc of the periphery of an inking cylinder journalled in the cartridge and usually referred to as an an-ilox rol1er. This arrangement is such that as the inking cylinder rotates a very thin coating of ink is spread evenly over its periphery in known manner. The inking cylinder is disposed in peripheral contact with a printing cylinder journalled in the cartridge. The periphery of the printing cylinder consists of a printing plate formed of resilient material. When the cartridge is inserted into operative position in a print tower, the printing cylinder can make peripheral contact with an impression cylinder journalled in the print tower and driven in timed relationship with the printing cylinder. Thus the printing plate is coated with ink by the inking cylinder and is capable of printing on a substrate fed between the printing cylinder and the impression cylinder.

The object of the present invention is to provide an improved flexographic printing cartridge adapted to accommodate different sizes of printing plates.

According to one aspect of the invention, a flexographic printing cartridge for a printing machine

includes means for positioning the axis of a printing cylinder along a locus so that interchangeable printing cylinders of different diameters can be accommodated in the cartridge in peripheral contact with an inking cylinder journalled about an axis in the cartridge and with an impression cylinder.

Preferably, the locus is a straight line. Preferably, also, the axis of the inking cylinder is fixed.

Preferably, the impression cylinder is journalled about an axis in the machine.

Alternatively, the impression cylinder is journalled about an axis in the cartridge.

'IL'he axis of the impression cylinder is preferably fixed.

According to another aspect of the invention, a print tower for a printing machine is fitted with a fiexographic printing cartridge according to any one of the preceding six paragraphs.

According to a further aspect of the invention, a printing machine has a print tower fitted with a flexographic printing cartridge according to any one of said six paragraphs.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawing which is a side elevation

of part of a print tower fitted with a flexographic printing cartridge.

Referring now to the drawing, a printing machine comprises a plurality of print towers such as 10, spaced longitudinally on a common base frame or bed along which there is fed a substrate consisting of a continuous web of paper. Mechanisms housed in the print towers, and the web, are driven in timed relationship with one another so that each tower can print on the web in a different colour in precise registration with other colours printed on the web by the other towers in order to produce a multi-coloured image. To facilitate changing the colour of the printing effected at each print tower 10, it is fitted in known manner with an interchangeable flexographic printing cartridge 12 containing an ink reservoir 14 into which there extends an arc of the periphery of an inking cylinder 16 journalled in the cartridge 12 about a fixed axis 18, a so-called doctoring blade (not shown) being carried by the reservoir 14 so that a very thin coating of ink is spread evenly over the periphery of the cylinder 16 as it rotates. Said cylinder is disposed in peripheral contact with a. printing cylinder 20 journalled in the cartridge 12. The periphery of the cylinder 20 consists of a printing plate 22 formed of resilient material with a bas-relief patterned surface produced photographically. When the cartridge 12 is inserted into operative position in the print tower 10 as illustrated, the printing cylinder can make peripheral

contact with an impression cylincl-#.--- 24 journalied in the print tower 10 about a fixed axis 26 and driven in timed relationship with the printing cylinder 20. Thus the high points of the printing plate 22 are coated with ink by the inking cylinder 16 so as to be capable of printing on the web (not shown) which is fed between the printing cylinder 20 and the impression cylinder 24 in timed relationship with said cylinders.

The printing machine, and notably the flexographic printing cartridge, described in general terms in the preceding paragraph is known. However, different cartridges containing printing cylinders of different diameters are conventionally needed in order to employ different sizes of printing plates. This need is now eliminated by providing means for positioning the axis of a printing cylinder along a locus 28 as illustrated so that interchangeable printing cylinders such as 2.0, 20A and 20B of different diameters can be accommodated in the cartridge 12 whilst retaining peripheral contact with both the impression cylinder 24 and the inking cylinder 16. The locus 28 shown is a straight line.

In a modification, the locus is curved. In another modification, the axis of the inking cylinder 16 is adjustable in position. In a further modification, the impression cylinder is journalled about a fixed axis in the cartridge. In yet another modification, the axis of the impression cylinder, whether journalled in the machine or

the cartridge, is adjustable in position. In yet a further modification, the substrate consists of a succession of separate sheets of paper, card or even metal, means being provided for accurately registering each sheet relative to the impression cylinder 24.

Claims

claims: - 1. A flexographic printing cartridge for a printing machine including means for positioning the axis of a printing cylinder along a locus so that interchangeabie printing cylinders of different diameters can be accommodated in the cartridge in peripheral contact wit. i an inking cylinder -journalled about an axis in the cartridge and with an impression cylinder.
2. A flexographic printing cartridge according to claim 1, wherein the locus is a straight line.
3. A flexographic printing cartridge according to either of the preceding claims, wherein the axis of the inking cartridge is fixed.
4. A flexographic printing cartridge according to any one of the preceding claims, wherein the impression cylinder is journalled about an axis in the machine.
5. A flexographic printing cartridge according to any one of claims I to 3, wherein the impression cylinder is journalled about an axis in the cartridge.
6. A flexographic printing cartridge according to claim 4 CyJ4 or claim 5, wherein the axis of the impression Lnder is fixed.
7. A print tower for a printing machine fitted with a flexographic printing cartridge according to any one of the preceding claims.

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B. A printing machine having a print tower fitted with a flexographic printing cartridge according to any one of claims I to 6.

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Amendments,to tbo.,clalms have been filed as follows Claims: - 1. A flexographic printing cartridge for a printing machine including means for positioning the axis of a printing cylinder along a locus so that interchangeable printing cylinders of different diameters can be accommodated in the cartridge in peripheral contact with an inking cylinder journalled about an axis in the cartridge and with an impression cylinder. 2. A flexographic printing cartridge according to claim 1, wherein the locus is a straight line. 3. A flexographic printing cartridge according to either of the preceding claims, wherein the axis of the inking cartridge is fixed. 4. A flexographic printing cartridge according to any one of the preceding claims, wherein'the impression cylinder is journalled about an axis in the machine. S. A flexographic printing cartridge according to any one of claims 1 to 3, wherein the impression cylinder is journalled about an axis in the cartridge. 6. A flexographic printing cartridge according to claim 4 or claim 5, wherein the axis of the impression cylinder is fixed. 7. A print tower for a printing machine fitted with a flexographic printing cartridge according to any one of the preceding claims.

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8. A printing machine having a print tower fitted with a flexographic printing cartridge according to any one of claims 1 to 6.
9. A flexographic printing cartridge for a printing machine, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawing.
10. A print tower for a printing machine fitted with a flexographic printing cartridge constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawing.
11. A printing machine having a print tower fitted with a flexographic printing cartridge constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawing.