DE20012271U1 - Printing machine and add-on printing unit for printing machines - Google Patents

Description

LEMCKE · BROMMER & PARTNER

PATENT ATTORNEYS BISMARCKSTR. 1 B · D-76133 KARLSRUHE

7 July 2000 18 179 (Bl/ko)

JEWA GmbH Production and sales of graphic machines Am Hölzel 12 76829 Landau

Printing machine and add-on printing unit for printing machines

LEMCKE · BROMMER & PARTNERS"

PATENT ATTORNEYS

BISMARCKSTR. 16 · D-761 33 KARLSRUHE

7 July 2000 18 179(BI/ko)

Description

The invention relates to a printing machine and in particular to an offset printing machine. In printing machines, the printing units determine the basic parameters for the number of colors to be used in printing. If more colors are to be printed than there are printing units, this is not possible with this machine and with a single printing process.

On the other hand, it is of course not necessarily economically sensible to design the printing press for the largest possible application and to provide the largest possible number of printing units and thus not to use all printing units for the majority of printing processes. From these conflicting requirements, it is easy to deduce that there is a need to make printing presses more flexible, which is why the object of the present invention is to be able to subsequently modify existing printing presses in such a way that they are suitable for printing another color or another coating, while at the same time this retrofitting should be associated with reasonable costs.

This object is achieved according to the invention in that the printing press has an add-on printing unit, that the add-on printing unit is a flexographic printing unit, and that the add-on printing unit can be attached and connected to the printing press in the area of the conveying path of the material to be printed.

By using a flexographic printing unit, in which the printing form attached to a printing form cylinder comes into direct contact with the material to be printed, a fully-fledged printing unit can be attached to the printing machine with comparatively little effort and thus existing printing machines can be flexibly retrofitted depending on the print job. Such a flexographic printing unit is not only able to apply an additional color to the material to be printed on with precision, but can also be used to surface

surface coating (e.g. using varnish or metallic paints) or finishing.

The flexographic printing unit is attached to a printing press intended for a numbering printing unit, which is usually referred to as a printing press with a plus version, in the area and instead of the numbering printing unit, i.e. in particular downstream of the printing units present in the printing press. The add-on printing unit is expediently arranged in the area of an impression cylinder already present in the printing press and in particular in the area of an impression cylinder intended for the numbering printing unit or for the last offset printing unit in the printing press. This advantageously results in further space savings, since an impression cylinder that is already present can simply be used as an impression cylinder for the flexographic printing unit. The add-on printing unit expediently consists only of a printing form cylinder that carries the printing form and which is supplied with the printing medium, i.e. the ink or coating, via an anilox roller and a chamber doctor blade. This flexographic printing unit is not only small, but also has the advantage of being able to be attached to the printing press in an area that usually still offers space for it.

A further advantage is that the add-on printing unit can be driven by the printing press itself and thus synchronized with the other printing units.

The inking unit used in the add-on printing unit, which applies the ink to the anilox roller via a chamber doctor blade, also reduces the equipment structure of the add-on printing unit compared to the inking units for offset printing units.

The present invention can be used in general in printing machines. However, the installation of an additional printing unit in the manner described is particularly suitable for sheet-fed or web offset presses.

It should be emphasized that the present invention extends not only to a printing press with an add-on printing unit, but also to an add-on printing unit itself, which can be attached to conventional printing presses and has the structure described above.

Further features and advantages of the present invention will become apparent from the following description of an embodiment with reference to the drawing, which shows in Figure 1 a sectional and schematic side view of the flexographic printing unit 2 attached to a printing press 1.

Of the printing press 1, only a rear housing wall 3 and a blanket cylinder 4 with an impression cylinder 5 are indicated here. The blanket cylinder and impression cylinder are arranged behind the other printing units of the printing press 1 (not shown in Figure 1), so that a material already printed with the remaining printing inks, in particular a sheet of paper (indicated schematically in Figure 1 by an arrow 6), is conveyed through the printing gap between the blanket cylinder and the impression cylinder.

A printing forme cylinder 7 of the add-on printing unit 2, i.e. the flexographic printing unit, engages the impression cylinder 5, which in the example shown is part of an offset printing unit together with the blanket cylinder 4, with the printing forme cylinder 7 carrying the flexographic printing form. The printing forme cylinder 7 receives its printing ink or the material for surface finishing via an anilox roller 8 that engages it, which is coated with printing ink or coating material (e.g. by means of varnish or metallic colors) in a known manner via a chamber doctor blade 9. The material to be printed, indicated by arrow 6, is applied to and printed by the printing forme in the printing gap formed between the printing forme cylinder 7 and the impression cylinder 5 and is transported further in the direction indicated by arrow 10.

From Figure 1 it is easy to see that the entirety of the printing unit and inking unit, i.e. the printing form cylinder 7, the anilox roller 8 and the chamber doctor blade 9, only require a very small amount of space, and this flexographic printing unit can be installed with short set-up times, which means that overall with simple

A printing unit for coloured impressions or surface finishes can be made available in addition to the offset printing units already present in the printing press.

In summary, the present invention offers the advantage that conventional printing machines can be retrofitted with a full-fledged printing unit in a simple and cost-effective manner, so that the application possibilities of existing machines can be expanded by another printing ink.

Claims (7)

1. Printing machine, in particular an offset printing machine, characterized in that it has an add-on printing unit ( 2 ), that the add-on printing unit ( 2 ) is a flexographic printing unit, and that the add-on printing unit can be attached and connected to the printing machine ( 1 ) in the region of the conveying path of the material to be printed ( 6 , 10 ). 2. Printing machine according to claim 1, characterized in that the installation of the printing unit ( 2 ) in a printing machine provided for a numbering printing unit takes place in the area of and instead of the numbering printing unit. 3. Printing machine according to claim 1 or 2, characterized in that the add-on printing unit ( 2 ) is arranged in the region of an impression cylinder ( 5 ) present in the printing machine ( 1 ), in particular in the region of an impression cylinder provided for the numbering printing unit or for an offset printing unit in the printing machine. 4. Printing machine according to claim 3, characterized in that the add-on printing unit ( 2 ) has a printing form cylinder ( 7 ) which cooperates with the impression cylinder ( 5 ). 5. Printing machine according to at least one of the preceding claims, characterized in that the add-on printing unit ( 2 ) has an inking unit ( 9 ) with a chamber doctor blade and an anilox roller ( 8 ). 6. Printing machine according to at least one of the preceding claims, characterized in that the printing machine ( 1 ) is a sheet-fed offset press. 7. Add-on printing unit ( 2 ) for printing machines ( 1 ) according to at least one of the preceding claims.