GB2025325A

GB2025325A - Convertible Offset Printing Press

Info

Publication number: GB2025325A
Application number: GB7924317A
Authority: GB
Original assignee: Polygraph Leipzig Kombinat Veb
Current assignee: Polygraph Leipzig Kombinat Veb
Priority date: 1978-07-17
Filing date: 1979-07-12
Publication date: 1980-01-23
Also published as: FR2431370A1; DE2928539A1; BG32009A1; SU1014759A1; CS218900B1; DD137557A1; FR2431370B3; GB2025325B; SE7906107L

Abstract

A printing unit for a rotary offset printing machine comprises a central impression cylinder (69) and four printing mechanisms mounted in bores in side wall members and each comprising a respective plate cylinder (65 to 68) and a respective blanket cylinder (61 to 64), the blanket cylinders (61 to 64) being journalled in eccentric bushes (74 to 77). The blanket cylinders (61 to 64) are selectably settable against the relatively small impression cylinder (69) for satellite printing; or they can be settable against each other in pairs to allow for either horizontal or vertical web paths, the impression cylinder being withdrawn axially out of contact with the blanket cylinder. Alternatively, the apparatus allows different printing mechanisms for horizontal and vertical web paths to be selectively mounted since the bores in the side wall member will accommodate either. <IMAGE>

Description

SPECIFICATION A Printing Apparatus The present invention relates to a printing apparatus for rotary roller offset printing.

Offset printing apparatuses are disclosed in the Journal "Deutscher Drucker", No. 1 9-20, 1977, pages 200 to 206. The printing apparatuses comprise four printing mechanisms, which each comprise a respective plate cylinder and a respective transfer cylinder, which are arranged around a satellite cylinder. For satellite printing, the four transfer cylinders are disposed in contact with the satellite cylinder.

With a view to resetting to blanket-offset printing, there are printing apparatuses, in which the transfer cylinders lying beside one another are settable against one another in pairs and separated from the satellite cylinder. By them, printing is possible according to the blanket-offset principle with vertical web guidance. Other printing apparatuses have this adjustability for the transfer cylinders lying above one another and make possible blanket-offset printing with horizontal web course. For re-setting, the transfer cylinders are usually journalled in eccentric bushes in the side walls of the printing apparatus.

These printing apparatuses have the common disadvantage that they are usable in blanketoffset printing each time only for the one special web course. Resetting of the printing apparatuses in the printing works from a horizontal to a vertical web course or conversely cannot be undertaken. Furthermore, it is not possible even by adaptation measures, for example by the use of different bearing bushes for the transfer cylinders and plate cylinders to mount printing mechanisms for the other web course in the side walls of the printing apparatus. The printing apparatus manufacturer must therefore produce special side walls for each web course of the blanket-offset principle, which causes increased production costs.

According to the present invention there is provided a printing apparatus for a rotary roller offset printing machine comprising a satellite cylinder and four printing mechanisms disposed around the satellite cylinder, the printing mechanisms each comprising a transfer cylinder disposed in a respective side wall bore and a plate cylinder, each transfer cylinder being journalled in an eccentric bush and selectably settable against the satellite cylinder, wherein the apparatus is so arranged that the transfer cylinders disposed beside or above one another are further settable against each other by rotation of the eccentric bushes, the wall bores being disposed at the same positions relative to one another, or wherein the apparatus is so arranged that the transfer cylinders disposed beside and above one another in the same printing apparatus are settable against each other by rotation of the eccentric bushes, in both arrangements the satellite cylinder having a diameter smaller than that of the transfer cylinders and the satellite cylinder being free of contact with the transfer cylinders when set against one another and being selectably drivable in the axial direction thereof to permit passage of a web through the apparatus and between the transfer cylinders set against one another.

Thereby, the printing apparatus manufacturer can with the same side walls mount printing mechanisms selectably for the blanket-offset principle with vertical or horizontal web course and the satellite principle, whereby the walls can be produced in lesser variety and in more economical numbers. In the case of the selectable settability of the transfer cylinders against one another in one printing apparatus, there is added in addition to the advantageous wall standardization that the printing apparatus can be reset in the printing works from the satellite principle selectably to blanket-offset printing with vertical or horizontal web course.Printing apparatuses embodying the present invention have furthermore the advantage that in accordance with the position of the cylinders, they need a smaller overall length compared with known apparatuses for blanket-offset printing with horizontal web course and satellite printing and/or a smaller overall height than known apparatuses for blanket-offset printing with vertical web course and satellite printing. Thanks to the smalier overall height, the inking and moistening mechanisms and the plate cylinders and transfer cylinders of the upper printing mechanisms are also better accessible.

Through laterai driving out of the machine frame of the printing units, the satellite cylinder for blanket-offset printing also lets itself be brought out of the range of the transfer cylinders.

Toothed engagements, which are in a given case to be disengaged on the resetting to blanketoffset printing, between the satellite cylinder and transfer cylinders are thereby avoided in a simple manner. The material web passes from the first to the second co-operating transfer cylinders of the printing unit without contact with the satellite cylinder. Thereby, smearing-off of the print is prevented and quality printing is made possible on surface-treated papers. Also, the satellite cylinder thus lets itself be cleaned well.

The side walls of all mentioned printing apparatuses can be standardized when the wall bores in all named variants have the same position relative to one another.

The eccentricity of the eccentric bushes can be dimensioned favourably small for construction and production of the diameter (d) of the printing cylinder has the following size ratio to the diameter (D) of the transfer cylinders:

Prerequisite for small selectable eccentricities are small resetting travels of the transfer cylinders for resetting from one to the other printing principle, thus small spacings between adjoining transfer cylinders set against the impression cylinders. This spacing would be 0 at the lower value of the formula, a generously dimensioned spacing being attained by the upper value.

The printing apparatus can be produced rationally if the side walls are divided between the upper and lower printing mechanisms.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings in which there is shown printing apparatuses for blanket-offset and satellite printing, schematically in side elevation and, as illustrated to greater scale, switch positions of eccentric bushes of the transfer cylinders of these printing apparatuses.

Fig. 1 shows a printing apparatus for blanketoffset printing wiht a vertical web course and satellite printing, Fig. 2 shows the switch positions of the eccentric bushes shown in Fig. 1, Fig. 3 shows a printing apparatus for blanketoffset printing with a horizontal web course and satellite printing, Fig. 4 shows the switch positions of the eccentric bushes shown in Fig. 3, Fig. 5 shows a printing apparatus for blanketoffset printing with selectable vertical and horizontal web course and satellite printing, and Fig. 6 shows the switch positions of the eccentric bushes shown in Fig. 5.

The printing apparatus illustrated in Fig. 1 comprises four transfer cylinders 1, 2, 3 and 4, which each co-operate with a respective plate cylinder 5, 6, 7 and 8. The transfer cylinders 1,2, 3 and 4 are arranged around a satellite cylinder 9.

Their cylinder spigots 10, 11, 12 and 13 are each journalled in a respective eccentric bush 1 4, 1 5, 1 6 and 1 7 with an eccentricity 1 8. The plate cylinder spigots 1 9, 20, 21 and 22 are each received by a respective eccentric bush 23, 24, 25 and 26 with an eccentricity 27.

In the illustrated setting 28 of the eccentric bushes 14, 1 5, 1 6 and 17, the transfer cylinders 1, 2, 3 and 4 are set against the satellite cylinder 9 and the printing apparatus operates in the satellite principle. Through turning the eccentric bushes 14, 1 5, 1 6 and 17 into the setting 30 (see Fig. 2), the transfer cylinders 1,2 and 3, 4 respectively lying beside one another are set against each other whilst separated from the satellite cylinder 9 and assume the positions drawn in dashed lines. Now blanket-offset printing is possible with a vertical web course.

Advantageously for this, the satellite cylinder 9 is stiil driven out through an opening (not shown) of a side wall of the printing unit. Possible smearingoff of the print on the satellite cylinder 9 on the path from the first to the second co-operating transfer cylinders is thus avoided. The setting of the plate cylinders 5, 6, 7 and 8 against the transfer cylinders 1, 2, 3 and 4 in their respective printing positions takes place by means of the eccentric bushes 23, 24, 25 and 26. To turn off the printing, the eccentric bushes 14, 1 5, 1 6 and 17 are turned into a setting 29 for both printing principles. The settings of the eccentric bush 1 7 are illustrated in Fig. 2, the settings of the bush 1 6 being in mirror image to them.The settings of the eccentric bushes 14 and 1 5 are in mirror image to those of the eccentric bushes 1 6 and 1 7. For improvement of the settability of the transfer cylinders 1.2, 3 and 4, their eccentric bushes 14, 1 5, 1 6 and 17 can be journalled in further eccentric bushes.

Fig. 3 shows a printing apparatus with four transfer cylinders 31, 32, 33 and 34, which each co-operate with a respective plate cylinder 35, 36,37 and 38. The transfer cylinders 31,32,33 and 34 are arranged around a satellite cylinder 39. Their cylinder spigots 40, 41, 42 and 43 are each journalled in a respective eccentric bush 44, 45, 46 and 47 with an eccentricity 48. The plate cylinder spigots 49, 50, 51 and 52 are each received by a respective eccentric bush 53, 54, 55 and 56 with an eccentricity 57. The wall bores for the eccentric bushes 44, 45, 46, 47, 53, 54, 55 and 56 have the same position relative to each other as the corresponding bores of the printing unit according to Fig. 1.

In the illustrated setting 58 of the eccentric bushes 44, 45, 46 and 47, the transfer cylinders 31, 32, 33 and 34 are set against the satellite cylinder 39 and the printing apparatus operates on the satellite principle. Through turning the eccentric bushes 44, 45, 46 and 47 into the setting 60 (see Fig. 4), the transfer cylinders 31, 33 and 32, 34 respectively lying above one another are set against each other whilst separated from the satellite cylinder 39 and assume the positions shown in dashed lines.

Blanket-offset printing with horizontal web course is now possible. For this, the satellite cylinder is still driven out through an opening (not shown) in a side wall of the printing unit for the reason given in respect of Fig. 1. The setting of the plate cylinders 35, 36, 37 and 38 against the transfer cylinders 31, 32, 33 and 34 in their respective printing positions takes place by means of the eccentric bushes 53, 54, 55 and 56. To turn off the printing, the eccentric bushes 44, 45, 46 and 47 are turned into a setting 59 for both printing principles. The settings of the eccentric bush 47 are illustrated in Fig. 4, the settings of the bush 46 being in mirror image to them. The settings of the eccentric bushes 44 and 45 are in mirror image to those of the eccentric bushes 46 and 47. For improvement of the adjustability of the transfer cylinders 31, 32, 33 and 34, their eccentric bushes 44, 45, 46 and 47 can be journalled in further eccentric bushes.

Due to the unchanged position of the wall bores for the cylinders, the printing apparatus shown in Fig. 1 or 3 can be mounted selectably with the same side wails.

The printing apparatus shown in Fig. 5 comprises four transfer cylinders 61, 62, 63 and 64, which each co-operate with a respective plate cylinder 65, 66, 67 and 68. The transfer cylinders 61, 62, 63 and 64 are arranged around a satellite cylinder 69. Their cylinder spigots 70, 71, 72 and 73 are each journalled in a respective eccentric bush 74, 75, 76 and 77 with the eccentricity 78.

The plate cylinder spigots 79,80,81 and 82 are received in a respective eccentric bush 83, 84, 85 and 86 with the eccentricity 87. An advantageous possibility of division of the side walls is indicated by the chain-dotted line.

In the illustrated setting 90 of the eccentric bushes 74, 75, 76 and 77, the transfer cylinders 61, 62, 63 and 64 are set against the satellite cylinder 69 and the printing unit operates on the satellite principle. Through turning the eccentric bushes 74, 75, 76 and 77 into the setting 88 (see Fig. 6), the transfer cylinders 61, 62 and 63, 64 respectively lying beside one another are set against each other whilst separated from the satellite cylinder 69 and assume the positions shown in dashed lines. Blanket-offset printing with vertical web course is now possible.When the eccentric bushes 74, 75, 76 and 77 are thereagainst turned into a setting 92, the transfer cylinders 61,63 and 62,64 respectively lying above one another are separated from the satellite cylinder 69 and set against each other.

They assume the positions, which are indicated by chain-dotted lines and in which blanket-offset printing is possible with a horizontal web course.

For blanket-offset printing, the satellite cylinder 69 is driven out through an opening (not shown) of a side wall of the printing apparatus for the reason given in respect of Fig. 1. The setting of the plate cylinders 65, 66, 67 and 68 against the transfer cylinders 61, 62, 63 and 64 into their respective printing positions takes place by means of the eccentric bushes 83, 84, 85 and 86.

To turn off the printing, the eccentric bushes 74, 75, 76 and 77 are in the case of blanket-offset printing with a vertical web course turned into the setting 89, in the case of blanket-offset printing with a horizontal web course into the setting 91.

In the case of satellite printing, the settings 89 as well as also 91 are suitable for turning off the printing. The settings of the eccentric bush 77 are illustrated in Fig. 6, the settings of the bush 76 being in mirror image to them. The settings of the eccentric bushes 74 and 75 are in mirror image to those of the eccentric bushes 76 and 77. For improvement of the adjustability of the transfer cylinders 61, 62, 63 and 64, their eccentric bushes 74,75,76 and 77 can bejournalled in further eccentric bushes.

In the embodiment shown in Fig. 5, the wall bores of the printing apparatus for the cylinder journalling have the same position relative to each other as the corresponding bores of the printing apparatus shown in Figs. 1 and 3. Thereby, printing apparatuses can with one and the same side walls be mounted for satellite printing and blanket-offset printing with vertical or horizontal web courses or printing units resettable additionally in respect of these web courses.

The above described embodiments make possible blanket-offset printing with vertical and - horizontal web courses as well as satellite printing while maintaining the same wall structure in roller offset printing apparatus, which are equipped with a satellite cylinder and four printing mechanisms each comprising a respective plate cylinder and a respective transfer cylinder and the transfer cylinders of which are journalled in eccentric bushes and settable against the satellite cylinder.

Claims

1. A printing apparatus for a rotary roller offset printing machine comprising a satellite cylinder and four printing mechanisms disposed around the satellite cylinder, the printing mechanisms each comprising a transfer cylinder disposed in a respective side wall bore and a plate cylinder, each transfer cylinder being journalled in an eccentric bush and selectably settable against the satellite cylinder, wherein the apparatus is so arranged that the transfer cylinders disposed beside or above one another are further settable against each other by rotation of the eccentric bushes, the wall bores being disposed at the same positions relative to one another, or wherein the apparatus is so arranged that the transfer cylinders disposed beside and above one another in the same printing apparatus are settable against each other by rotation of the eccentric bushes, in both arrangements the satellite cylinder having a diameter smaller than that of the transfer cylinders and the satellite cylinder being free of contact with the transfer cylinders when set against one another and being selectably drivable in the axial direction thereof to permit passage of a web through the apparatus and between the transfer cylinders set against one another.

2. An apparatus as claimed in claim 1, wherein in both arrangements the bores are disposed as the same position relative to one another.

3. An apparatus as claimed in either claim 1 or claim 2, wherein the ratio of the diameter (d) of the satellite cylinder to the diameter (D) of the transfer cylinders is given by:

4. An apparatus as claimed in any one of the preceding claims, wherein the side walls are divided between upper and lower printing mechanisms.

5. A printing apparatus substantially as hereinbefore described with reference to Fig. 1 and Fig. 2 of the accompanying drawings.

6. A printing apparatus substantially as hereinbefore described with reference to Fig. 3 and Fig. 4 of the accompanying drawings.

7. A printing apparatus substantially as hereinbefore described with reference to Fig. 5 and Fig. 6 of the accompanying drawings.