GB2215275A

GB2215275A - Offset and perfecting printing machine

Info

Publication number: GB2215275A
Application number: GB8902254A
Authority: GB
Inventors: Arndt Jentzsch; Klaus Schanze
Original assignee: Kombinat Polygraph Werner Lamberz VEB; Polygraph Leipzig Kombinat Veb
Current assignee: Kombinat Polygraph Werner Lamberz VEB; Polygraph Leipzig Kombinat Veb
Priority date: 1988-02-04
Filing date: 1989-02-02
Publication date: 1989-09-20
Anticipated expiration: 2009-02-02
Also published as: JP2832245B2; GB8902254D0; GB2215275B; DE3901175A1; FR2626815A1; JPH01288445A; IT1232568B; IT8967067A0; FR2626815B1; DD285878A7; DE3901175C2

Description

1 PRINTING MACHINE The present invention relates to a printing machine,

especially for first form printing or for the first and perfecting form printing, particularly in multi-colour printing.

A sheet-printing machine is known (DE 3203948) in which rubber cylinders of individual printing units are arranged in series one contacting the other for ink transmission. A cylinder, which also represents a feed drum and a deflecting system of a discharge chain circle, is pressable against a rubber cylinder. In that case it i3 disadvantageous that numerous ink gaps are necessary for the printing image transmission, which cause point enlargement, doubling phenomena and thus a loss in quality. Moreover, regulation of the ink layer thickness in correspondence with the different lengths of path of the ink to the sheets or web material to be printed on is difficult in these machines due to the above average number of gaos. This design not usable for modern machines with a large number of printing units, for example a ten-colour machine, in view of the described disadvantages.

A further disadvantage is that first and perfecting form printing is not possible with this design.

There is thus a need for a machine which may provide an increase in the quality of printing, a simplification of sheet'or web guidance and thereby an increase in printing perfdrmance, and enhancing of the utility of a printing machine operating on the image transport principle. Such a machine should preferably have a small number of ink gaps, be able to be equipped with a large number of printing units, and be capable of carrying out first form printing or first and perfect ing form printing.

According to the present invention there is provided a printing machine comprising sheet or web material feed means, sheet or web material discharge means, transfer means to transfer sheet or web material from the feed means to the discharge means, the transfer means comprising a central printing cylinder co-operable with the feed means and a cylinder system which is arranged downstream of the central printing cylinder and upstream of the discharge means with respect to a direction of movement of sheets or web material between the feed means and the discharge means and which comprises at least one perfecting cylinder, an endless, printing image collecting element contac+ ling the central printing cylinder, and at least one printing unit co- operable with the endless element and comprising a printing cylinder, a counterpressure cylinder and inking and moistening means, the endless element extending through a pressure zone between the printing and counterpressure cylinders of said at least one unit.

The central printing cylinder can be constructed as sheet-guiding central printing cylinder and provided with gripper means for sheets, or as a webguiding central printing cylinder. The cylinder system can comprise a webguiding perfecting cylinder, or at least one sheet- perfecting cylinder with at least one gripper system; or a sheetperfecting cylinder with at least one gripper system and a transfer cylinder with at least one gripper system, or two transfer cylinders selectably constructed as sheet-turning cylinders or transport cylinders, or four transfer cylinders selectably constructed as sheet-turning cylinders or transport cylinders.

The machine may comprise, as perfecting means, a single printing Q 1 - 3 unit comprising a printing cylinder, inking and moistening means, and an offset cylinder disposed in pressurable contact with the printing cylinder and the cylinder system. Alternatively, the perfecting means may be a further printing image collecting element disposed in pressurable contact with the cylinder system, with at least one printing cylinder, inking and moistening means and a counterpressure cylinder.

Expediently, at least one printing cylinder with inking and moistening mechanism is arranged above the upper run of the erdle s element, or at least one printing cylinder is arranged below the element, or at least one printing cylinder with inking and moistening mechanism is arranged above the upper run of the element and at least one printing cylinder with inking and moistening mechanism is arranged below the lower run of the element. The printing image collecting element may be constructed as an endless offset blanket, or at least one offset blanket piece may be firmly connected with the element, or the element can be provided with at least one gripper system for an offset blanket piece.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which:

Fi 9. 2 Fig. 1 is a schematic elevation of a first printing machine embodying the invention, for selectable first and perfecting form printing (single printing unit); is a schematic elevation of a second printing machine embodying the invention, for selectable first and perfecting form printing (printing image collecting element); 1 0 Fi g. 3 is a schematic elevation of a third printing machine embodying the invention, for selectable first and perfecting form printing (single printing unit and transfer cylinder); Fig. 4 is a schematic elevation of a fourth printing machine embodying the invention, for selectable first and perfecting form printing (sheet transfer system PLANETA); Fig. 5 is a schematic elevation of a fifth printing machine embodying the invention, for selectable first and perfecting form printing (sheet transfer system MILLER); and Fig. 6 is a schematic elevation of a sixth printing machine embodying the invention, for first and perfecting form printing.

Referring now to the drawings, there is shown a printing machine which, in embodiments intended for sheet printing, Comprises a sheetguiding system and a printing-image-guiding system. The sheet- guiding system comprises (Fig. 1) a sheet feed with a feeder 1, a feed table 2 and a sheet transfer device 3, for example a preliminary gripper, a sheet transport system arranged downstream of the sheet transfer device and constructed as a sheet-guiding central printing cylinder 4.1, and a sheet discharge device constructed as sheet deposit 5.

A cylinder system 27 is interposed between the cylinder 4.1 and the sheet deposit 5. The cylinder system 27 is part of perfecting equipment 28. The cylinder system 27 comprises a sheet-perfecting cylinder 29.1 (Fig. 1), or a sheet-perfecting cylinder 29.1 and a transfer cylinder 30 (Figs. 2 and 3), or two cylinders selectably 1 TA operable as sheet-turning cylinders or transport cylinders (PLANE system according to DD 54 703, Fig. 4), or four cylinders selectab,y operable as sheet-turning cylinders or transport cylinders (MILLER system according to DE 1 107 246, Fig. 5).

In first and perfecting form printing by the PLANETA system, the first sheet-turning cylinder functions as sheet-turning cylinder 31 and the second sheet-turning cylinder as sheet-perfecting cylinder 29.1. Sheet turning in that case takes place in known mode and manner either between the central printing cylinder 4.1 and the first sheet turning cylinder 31, or between the first sheet-turning cylinder 31 and the sheet-perfecting cylinder 29.1. No sheet turning takes Dlace in first form printing and the cylinder system 27 consists only of transport cylinders 32. The two sheet-turning cylinders 29.1 and 31 are usable as transport cylinders 32 after resetting of the systems in known mode and manner.

For first and perfecting form printing by the MILLER system, the first, second and third sheet-turning cylinders 31, 33 and 34 function as sheet-turning cylinders and the fourth sheet-turning cylinder as sheet-perfecting cylinder 29.1. Sheet turning takes place between the second and third sheet-turning cylinders.- No sheet turn ing takes place in first form printing and the cylinder system 27 con sists only of transport cylinders 32. The four sheet-turning cylinders are usable as transport cylinders 32 after resetting of the systems.

The central printing cylinder 4.1, the sheet-perfecting cylinder 29.1, the transfer cylinder 30, the sheet-turning cylinders 31, 33 and 34 and the transport cylinders 32 each have two gripper systems 6, wherein the number of the gripper systems can be increased or 6 reduced.

In embodiments of the machine as a roller printing machine for web printing, the machine comprises a web-guiding system and a printing-imageguiding system. The web-guiding system (Fig. 6) comprises a web 'feed with an unreeling device 22 with a web feed roller 23, a web-guiding central printing cylinder 4.2 and a web discharge device constructed as reeling device 24 with web-discharge rollers 25. A web-guiding perfecting cylinder 29.2 is arranged downstream of the central printing cylinder 4.2. The printing-image-guiding system comprises a printing image collecting element 7, which is constructed as endless belt guided over two deflecting rollers 8 and is disposed in contact with the cylinder 4.2. The printing-imageguiding system also comprises at least one printing unit, which consists of a printing cylinder 9, an inking mechanism 10, a moistening mechanism 11, and a counterpressure cylinder 12. The upper run 13 of the element 7 runs through the contact zone between printing cylinder 9 and the counterpressure cylinder 12 (Figs. 1, 4 and 5) An embodiment is illustrated in Fig. 2, wherein a number of printing units are disposed in contact with the upper run 13 of the printing image collecting element 7 and a further number of printing units are disposed in contact with the lower run 14 of the element 7.

Fig. 3 shows an embodiment wherein the printing units, consisting of printing cylinder 9 with inking and moistening mechanisms 10 and 11 and counterpressure cylinder 12, are disposed in contact with the lower run 14 of the element 7.

An embodiment is illustrated in Fig. 6 in which a printing image collecting element 7 is associated with the central printing cylinder ir c 4.2. At least one drying device 15 acts on the central printing cylinder (Fig. 2) and at least one washing device 16 and a patch collector 17 act on the element 7.

The printing image collecting element 7 can be constructed as endless offset blanket 18 (Fig. 1), or at least one offset blanket piece 19 is connected with the element 7, wherein a gao for the gripper system 6 is provided in the case of several offset blanket pieces connected with the element 7 (Fig. 2), The element 7 can also consist of at jeast one offset blanket piece 19 held by a front edge or a front edge and rear edge and/or side edge gripper system 20 (fig. 3). Perfecting equipment 28 is associated with the perfecting cylinder 29. The perfecting equipment 28 consists of a single printing unit 28.1 or of a further printing image collecting element 28.2. The single printing unit 28.1 consists of an offset cylinder 26 and a printing cylinder 9 with moistening and inking mechanisms 10 and 11 The further printing image collecting element 28.1 is constructed in analogous manner to the element 7.

In use of the machine for sheet printing, a sheet withdrawn from the feeder 1 is conducted by way of the feed table 2 and the sheet transfer device 3 to the central printing cylinder 4.1. After printing, the ink applied to the sheet is dried by means of the drier 15.

The printing image collecting element 7 runs through the pressure zone between the printing cylinder 9 and the counterpressure cylinder 12 of the first printing unit and takes over the printing image of the first colour.

The further colours are applied in the same mode and manner in correspondence with the number of printing units. The collected colour image is transferred to the sheet on passage through the pressure - 8 zone between the central printing cylinder and the printing image collecting element.

After transfer of the sheet to the perfecting cylinder 29.1, the printing of the rear side of the sheet takes place by perfecting equipment 28 in the form of the single printing unit 28.1 or the further printing image collecting element 28.2. Thereafter, the sheet is conducted to the sheet deposit device 5.

The printing of a web takes place in analogous manner.

The advantages of the printing machine lie in simplified sheet guidance for first and perfecting form printing, and printing without doubling problems with a small number of ink gaps.

9

Claims

CLAIMS 1. A printing machine comprising sheet or web material feed means,

sheet or web material discharge means, transfer means to transfer sheet or web material from the feed means to the discharge means, the transfer means comprising a central printing cylinder co-operable with the feed means and a cylinder system which is arranged downstream of the central printing cylinder and upstream of the discharge means with respect to a direction of movement of sheets or web material between the feed means and the discharge means and which comprises E-,

J'O least one perfecting cylinder, an endless, printing image collecting element contacting the central printing cylinder, and at least one printing unit co-operable with the endless element and comprising a printing cylinder, a counterpressure cylinder and inking and moistening means, the endless element extending through a pressure zone between the printing and counterpressure cylinders of said at least one unit.
2. A printing machine as claimed in claim 1, wherein the central printing cylinder is provided with gripper means for gripping sheets.
3. A printing machine as claimed in claim 1, wherein the central printing cylinder is arranged to guide a web between the feed means to 20 the discharge means.
4. A printing machine as claimed in claim 3, wherein the perfecting cylinder is arranged to guide said web.
5. A printing machine as claimed in claim 2, wherein the perfecting cylinder is provided with sheet gripper means.
6. A printing machine as claimed in claim 5, wherein the cylinder system further comprises a transfer cylinder provided with sheet gripper means.
7. A printing machine as claimed in any one of claims 1, 2 and 5, wherein the cylinder system further comprises two cylinders selectably usable for sheet turning or sheet transport.
8. A printing machine as claimed in any one of claims 1, 2 and 5, wherein the cylinder system further comprises four cylinders select10 ably usable for sheet turning or sheet transport.
9. A printing machine as claimed in claim 1, comprising a further printing unit operable as perfecting means, the further unit comprising a printing cylinder, inking and moistening means, and an offset cylinder contacting the printing cylinder of the further unit and the cylinder 15 system.
10. A printing machine as claimed in claim 1, comori"sing a further endless, printing image collecting element operable as perfecting means and a further such printing unit co-operable with the further endless element, the further endless element contacting the cylinder 20 system.
11. A printing machine as claimed in any one of claims 1 to 9, c :r 1 - 11 wherein the printing cylinder of said at least one printing unit is arranged above an upper run of the endless element.
12. A printing machine as claimed in any one of claims 1 to 9, wherein the printing cylinder of said at least one printing unit is arranged below a lower run of the endless element.
13. A printing machine as claimed in claim 11, comprising a further such printing unit co-operable with the endless element, the printing cylinder of the further unit being arranged below a lower run of the endless element.
14. A printing machine as claimed in any one of the preceding claims, wherein the endless element has the form of an offset blanket.
15. A printing machine as claimed in any one of claims 1 to 13, wherein the endless element is provided with at least one offset blanket portion.
16. A printing machine as claimed in any one of claims 1 to 13, wherein the endless element is provided with at least'one gripper for an offset blanket portion.
17. A printing machine substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.
18. A printing machine substantially as hereinbefore described with - 12 reference to Fig. 2 of the accompanying drawings.
19. A printing machine substantially as hereinbefore described with referenc e to Fig. 3 of the accompanying drawings.
20. A printing machine substantially as hereinbefore described with 5 reference to Fig. 4 of the accompanying drawings.
21. A printing machine substantially as hereinbefore described with reference to Fig. 5 of the accompanying drawings.
22. A printing machine substantially as hereinbefore described with reference to Fig. 6 of the accompanying drawings.

MDUBIled 1959 at The Patent Office, State House, 66-71 High Holborn, London WC1R 4TP. Further copies xnkv be obtainedfrom The Patent DMcLSales Branch, St Mary Cray, Orpington, Kent BR,5 3RD. Printed by MultaPlex techniques Itd, St Mary Cray, Kent, Con. 1/87 v 1 Q