Method for color measurement in printing presses

• US 8,887,637 B2
• Filed: 03/30/2007
• Issued: 11/18/2014
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Heidelberger Druckmaschinen Ag
• Original Assignee: Heidelberger Druckmaschinen Ag
• Inventors: Huber, Werner, Schneider, Manfred, Geissler, Wolfgang
• Primary Examiner(s): BANH, DAVID H
• Application Number:
  US11/731,472
• Publication Number:
  US 20070227389A1
• Time in Patent Office: 2,790 Days
• Field of Search: 101/484, 101/485
• US Class Current: 101/484
• CPC Class Codes: B41F 33/0036 Devices for scanning or checking the printed matter for quality control

Abstract

A color measurement on printed materials produced by a printing press is performed by at least a first color measuring device installed in the printing press and at least a second color measuring device. A signal is output by the first color measuring device in the printing press when the measured color values registered on the printing materials are located within a predefined tolerance limit for a predefined period and that, after the signal has been output, a color measurement on one of the printed materials thus produced is performed with the second color measuring device.

Claims

1. A method for color measurement on printed materials produced by a printing press, which comprises:

measuring color values on the printed materials with at least one first color measuring device installed in the printing press;

determining that the printing press has reached a stable production state when measured color values registered on the printed materials are located within a predefined tolerance range for a predefined period;

after the printing press has reached the stable production state, outputting a signal from the first color measuring device on a monitor; and

after the signal has been output from the first color measuring device on the monitor, performing a color measurement on one of the printed materials produced during the reached stable production state with at least one second color measuring device.

2. The method according to claim 1, wherein the second color measuring device is located outside the printing press.

3. The method according to claim 1, wherein the first color measuring device and the second color measuring device are connected to each other via a communications link.

4. The method according to claim 1, wherein the predefined period corresponds to a predefined time interval.

5. The method according to claim 1, wherein the predefined period corresponds to a predefined number of printed materials produced.

6. The method according to claim 1, wherein at least one of the first color measuring device and the second color measuring device communicates with a control computer of the printing press.

7. The method according to claim 1, which comprises:

deriving measured color values from the color measurement on the printed material with the second color measuring device, and comparing the measured color values with a print original; and

based on a determined deviation of the measured color values, performing color control operations in inking units of the printing press.

8. The method according to claim 1, which comprises measuring the printed materials with the first color measuring device during a continuous printing operation and defining a tolerance limit for the measured colored values determined in the process, and, if the tolerance limit is exceeded, outputting a warning signal via an operating device.

9. The method according to claim 8, which comprises measuring the printed materials during the continuous printing operation by way of the first color measuring device, calculating a trend of color deviations in a computer and, if the trend would lead to a violation of predefined tolerance limits when extrapolated, outputting a warning signal via an operating device.

10. The method according to claim 1, wherein the signal from the first color measuring device is output only after the printing press has reached the stable production state.

11. The method according to claim 1, wherein the signal output on the monitor indicates that the printing press has reached the stable production state.