Method for controlling the ink feed of an offset printing press for model based color control and printing press for carrying out the method

Abstract

A method is provided for controlling an ink feed of an offset printing press having a control computer and at least one inking unit controlled by the control computer. The control computer calculates an ink layer thickness necessary for the color through the use of spectral reflectance values and, in order to set the calculated ink layer thickness, performs necessary setting operations on the inking unit. A printing press having an apparatus for carrying out the method is also provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic, side-elevational view of a sheet fed rotary printing press having a control system according to the invention;

FIG. 2A is a diagram showing the course of the calorimetric L value over the associated ink layer thickness;

FIG. 2B is a diagram showing the course of the calorimetric a value over the ink layer thickness; and

FIG. 2C is a diagram showing the course of the calorimetric b value over the ink layer thickness.

Claims

1. A method for controlling an ink feed of an offset printing press having a control computer and at least one inking unit controlled by the control computer, the method comprising the following steps: calculating, with the control computer, an ink layer thickness necessary for a color by using spectral reflectance values; andperforming necessary setting operations on the inking unit, with the control computer, to set the calculated ink layer thickness.

2. The method according to claim 1, which further comprises relating the ink layer thickness to be calculated to a given ink layer thickness, during the step of calculating the ink layer thickness.

3. The method according to claim 1, which further comprises relating the spectral reflectance value of the current printing material to a reflectance value of the ink, during the step of calculating the ink layer thickness.

4. The method according to claim 1, which further comprises calculating densitometric desired color values from the reflectance values.

5. The method according to claim 1, which further comprises calculating colorimetric desired color values from the reflectance values.

6. The method according to claim 1, which further comprises calculating calorimetric or densitometric desired color values by using reflectance values for ink and/or printing material measured by using polarizing filters.

7. The method according to claim 1, which further comprises entering the reflectance values for printing material or ink or the associated ink layer thickness into the control computer.

8. The method according to claim 1, which further comprises storing the reflectance values for printing material or ink or the associated ink layer thickness in the control computer.

9. The method according to claim 1, which further comprises registering the reflectance values for printing material or ink with a measuring instrument connected to the control computer.

10. A printing press, comprising an apparatus for carrying out the method according to claim 1.