Oce ColorStream, User Manual

Page: 255 / 524

Correcting Color Separation Shifts
Introduction
In the case of color printing, the individual color separations are first collected in succession
on the transfer belt and then transferred together to the paper web. Under certain circum-
stances, the longitudinal register between black and the various colors used may vary.
If a very high level of accuracy is required for the longitudinal register when printing in
color, the individual color separation shifts can be checked and corrected accordingly by
members of the "Key Operator" user group or above.
To Correct Color Separation Shifts
#
Proceed as follows:
Approximately 10 accumulative cycles of the test print job for full-color
printing:
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‘Printing Test Print Jobs — Overview’ on page 200
■
For information on the test sequences, see: ‘'5C_PrintQualityInspection.600'
Test Print Job’ on page 202 .
1.
Stop the test print and remove the paper web if necessary:
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To make corrections to the upper side of the paper web, see: ‘Checking the
print image ’ on page 199 .
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Likewise, to correct values for the underside of the paper web, see: ‘Removing
the paper web ’ on page 155 .
2.
#
Proceed as follows:
Measure the longitudinal register in the color-nonius fields of the last two ac-
cumulative cycles:
All color fields are based on black. The numerical values indicate shifts from
the black color separation:
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Above the lines: in µm
■
Beneath the lines: in mpt
3.
Chapter 6 - Operating the Printing System 255
Correcting Color Separation Shifts