Method for producing multicolor printing

Abstract

A method for producing multicolor printing, by using printing plates provided digitally with images and/or print, represents an efficient solution for multi-color printing, in particular in a large format. Printing plates, which had been used in a printing press, are removed from the printing form cylinders, are sent to a device for neutralization, and are neutralized. The neutralized printing plates are fixed at correct registration in an exposure and development unit where they are exposed and developed. The printing plates provided with new images are again applied to the printing form cylinder.

Description

FIELD OF THE INVENTION

[0001] The present invention is directed to a method for producing multicolor printing. Coated printing plates are provided digitally with images and/or print in correct registration in an exposure and development unit. These printing plates can be Reused.

BACKGROUND OF THE INVENTION

[0002] In the prior art, the direct illustration of printing formes from a digital data store from the pre-print stage, such as the prepress area, takes place by the utilization of one of three systems as discussed in the publication Teschner, “Offsetdruck-technik” [Offset Printing Techniques], 1995, publ. by Fachschriftenverlag. These three systems are as follows:

[0003] Transferring all digital image data for all ink colors to individual printing plates outside of the printing press=computer-to-plate.

[0004] Transferring all digital image data for all ink colors to several printing plates in the printing press=computer-to-press.

[0005] Transferring all digital image data for all ink colors to Re-writable printing forme cylinders, such as image carrier drums in the printing press=computer-to-print.

[0006] While disposable printing plates; i.e. printing plates that cannot be used again, are employed with the first two systems set forth above, no printing plates are used with the third system. Instead, the printing forme cylinder itself is provided with images.

[0007] It is a limitation of these prior art systems that none of the three above-described systems offers an efficient solution, in particular in connection with multicolor printing in a large format.

OBJECT AND SUMMARY OF THE INVENTION

[0008] It is the object of the present invention to provide a method which accomplishes an efficient solution for multi-color printing, in particular in a large format.

[0009] In accordance with the present invention, this object is attained by the provision of a method for producing multicolor printing using printing plates provided digitally with images and/or print. Previously used printing plates are removed from a forme cylinder and are neutralized in a suitable neutralizing device. This neutralization removes the prior images or print. These plates may then be coated and the now neutralized and possibly coated plates are placed, in correct registration, in an exposure and development unit. The plates are then exposed and developed. These plates, which have now been provided digitally with new images and/or print are then again applied to the printing forme cylinder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0010] At the conclusion of the production of a multi-color printing task or job in a printing press, the printing plates that were used for the multi-color printing job are removed from the printing forme cylinders on which they had been clamped. This plate removal is typically accomplished through the use of automatic plate-changing devices, with which the used printing plates are removed from the printing forme cylinders. These automatic plate-changing devices then are used to also supply fresh printing plates to the printing forme cylinders.

[0011] Once they have been removed from the printing forme cylinders, the used printing plates are then conducted to a device for neutralizing the used printing plates and are neutralized there. In this context, neutralization of the plates is understood to mean that the previously used printed image and/or print is removed from the printing plates. This removal takes place by means of a chemical, a mechanical or a thermal process, and preferably by means of laser techniques. An essentially even surface tension is achieved by means of the neutralization.

[0012] Thereafter, the now neutralized or cleaned printing plate is again provided with new images and/or print. This provision of new images and/or prints may take place in one way directly, for example by means of an ink jet printer or a transfer tape, or in another way by means of the use of a pre-applied imprinting of the printing plate; i.e. lacquer and photo-sensor device or thermal layer. This application of new images and/or print onto the printing plate takes place digitally from digital data sets (CtP).

[0013] In order to assure the capability of the newly applied images and/or prints placed on the printing plates to be in proper alignment or registration when the printing plates are Re-installed on the printing forme cylinder, the printing plate must be situated in place in the exposure unit in proper registry by use of the registration system of the printing itself, or through the use of a second registration system which makes reference to the registration system of the printing plate. This second registration system must be designed to be dimensionally stable.

[0014] Following the application of these new images and/or print, including their development, the printing plates are again brought to the printing forme cylinder, and are Re-installed on the printing forme cylinder preferably by operation of the automatic plate-changing device.

[0015] The printing plate used for this method is preferably made of special steel, is dimensionally stable and is free of depressions. This printing plate can be provided with further improvements of the surface known for offset printing, for example a chromium layer.

[0016] While a preferred embodiment of a method for producing multicolor printing in accordance with the present invention has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example the material to be printed, the specific type of press and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.

Claims

1. A method of producing multicolor printing using printing plates provided digitally with images and/or print including: providing a printing forme cylinder adapted for receiving printing plates; removing printing plates used in a previous printing task for said printing forme cylinder; providing a printing plate neutralizing device useable to remove images and print from printing plates; delivering said used printing plates to said printing plate neutralizing device and neutralizing said used printing plates in said printing plate neutralizing device; applying a coating to said neutralized printing plates; providing a printing plate exposure and development unit; securing said coated printing plates in proper registration in said exposure and development unit; providing new images and print to said coated printing plates in said exposure and development unit and developing said new images; and Re-applying said coated printing plates with said new images and print to said printing forme cylinder.

2. A method of providing multicolor printing using printing plates providing digitally with images and/or print comprising: providing a printing forme cylinder adapted for receiving printing plates; removing printing plates used in a previous printing task from said printing forme cylinder; providing a printing plate neutralizing device useable to remove images and print from printing plates; delivering said used printing plates to said printing plate neutralizing device and neutralizing said used printing plates in said printing plate neutralizing device; providing a printing plate exposure and development unit; securing said neutralized printing plates in proper registration in said exposure and development unit; providing new images and print to said neutralized printing plates in said exposure and development unit and developing said new images; and Re-applying said neutralized printing plates with said new images and print to said printing forme cylinder.

3. The method of claim 1 further including providing a registration system for the printing plate and using said printing plate registration system for securing said printing plates in proper registration in said exposure and development unit.

4. The method of claim 2 further including providing a registration system for the printing plate and using said printing plate registration system for securing said printing plates in proper registration in said exposure and development unit.

5. The method of claim 1 further including providing an automatic plate changing device and using said automatic plate changing device for removing printing plates from said printing forme cylinder and for Re-applying printing plates to said printing forme cylinder.

6. The method of claim 2 further including providing an automatic plate changing device and using said automatic plate changing device for removing printing plates from said printing forme cylinder and for Re-applying printing plates to said printing forme cylinder.

7. The method of claim 1 further including neutralizing said used printing plates using a laser neutralization technique.

8. The method of claim 2 further including neutralizing said used printing plates using a laser neutralization technique.

9. The method of claim 3 further including providing an exposure and development unit registration system, and securing said printing plates in proper registration in said exposure and development unit using said exposure and development unit registration system and said printing plate registration system.

10. The method of claim 4 further including providing an exposure and development unit registration system, and securing said printing plates in proper registration in said exposure and development unit using said exposure and development unit registration system and said printing plate registration system.