Patent Application
20070125250
This application claims the priority of German Patent Document No. 10 2005 056 980.3, filed Nov. 30, 2005, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a printing cylinder for a rotary web press on which at least one printing form has been installed. The invention further relates to a method for operating a rotary web press.
In known printing presses, printing or plate cylinders with clamping systems are used in the printing units to clamp appropriate printing forms on this printing or plate cylinder. In the case of the printing forms, they are predominantly disposable plates which are customarily produced off-press in a plate setter. Such disposable printing plates, on which the print image is usually baked, are used mostly in very high print runs. After printing, these disposable printing plates are thrown away.
In the area of digital printing, for example the DICOWEB of the applicant, it is known to use printing or plate cylinders in the printing unit which use sleeves in place of the printing plates and thus to function without traditional plate clamping or clamping mechanisms. In digital presses, the sleeves are installed onto the printing or plate cylinder with the assistance of an air cushion. Printing form costs represent an increasingly dominant portion of production costs, particularly with small print runs. An imaging procedure is known especially for the DICOWEB (digital press) of the applicant which makes it possible to produce printing forms for smaller print runs more economically. However, because of the erase cycle which follows the printing process, the potential size of the print run is limited. The manufacturing process for these printing forms can be carried out both in-press and off-press.
The object for the inventors was to improve a rotary web press, independently of whether it operates with digital in-press imaging or with a conventional plate.
The inventors recognized that it is possible to use conventional printing plates as well as sleeves on a modified printing cylinder of a press and thus to install the most suitable and economical printing form on the printing cylinder or plate cylinder without taking great conversion measures.
From the knowledge thus gained, the inventors provide an improved printing cylinder for a rotary web press, on which at least one printing form has been installed, to the effect that the printing cylinder consists of at least one cylinder core and an adapter sleeve installed thereon, wherein the adapter sleeve is configured such that either printing forms in the shape of sleeves or printing plates can be attached thereto.
As a result, it is possible for the printing press operator to use the economical alternative for the particular size of print run without taking great conversion measures. In this way, the proportionately low-priced directly imaged sleeves can be used for single print orders, while the correspondingly economical disposable plate is used for the large run portion. The invention makes it possible to use sleeves either as endless sleeves or as sleeves with a welded seam.
As an alternative, or as a supplement to this, conventional printing plates with bevels can also be used which are fixed in lock-up slots on the adapter sleeves. The adapter sleeve can be implemented optionally without a lock-up slot or with at least one lock-up slot.
In the embodiment without a lock-up slot, this adapter sleeve is suitable for sleeves. In the embodiment with at least one lock-up slot it is preferably suitable for printing plates. It is advantageous on adapter sleeves if several such lock-up slots are disposed thereon. They can preferably be located offset to each other relative to the circumference of the adapter sleeve.
The offset of the lock-up slots on the circumference of the adapter sleeve can be 90°, 120° or even 180°. With the lock-up slots offset to each other at 90°, four lock-up slots can, for example, be incorporated on the cylinder around the circumference of the printing cylinder. However, it can also be fewer than four lock-up slots or more than four lock-up slots on the printing cylinder with a 90° offset.
With a 120 degree-offset for the lock-up slots on the circumference of the printing cylinder, ideally three lock-up slots and thus three printing plates can be disposed equally spaced around the circumference of the printing cylinder. However, in this case also, fewer or more in the number of lock-up slots can be disposed relative to the circumference of the printing cylinder which include a 120 degree-offset.
In order to save weight in the area of the printing cylinder, it is advantageous if the adapter sleeve consists of a metal foam and/or a plastic foam.
In addition to the printing cylinder for a rotary web press, the inventors also provide a new method for operating a rotary web press. The new method is that the printing cylinder consists of at least one cylinder core and an adapter sleeve, wherein the adapter sleeve is installed on this cylinder core and is configured such that printing forms in the shape of sleeves or printing plates can be attached to the adapter sleeve, where either sleeves or printing plates are attached to the adapter sleeve before the printing process, depending on the size of the print run.
In the new method, imaging the printing forms is envisaged either inside or outside the printing press as an option. Imaging the printing forms inside the press results in an enormous savings in time.
Preferred developments of the invention will become clear from the following description.
Different embodiments of the invention will be explained in more detail with reference to the drawings, without being limited to them.
Embodiments of the present invention are described with reference to FIGS. 1 to 5.
It goes without saying that the previously named features and the features of the claims can be used not only in the particular combinations given but also in other combinations or standing alone within the scope of the invention.
As discussed above, the foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 056 980.3 | Nov 2005 | DE | national |
