Epson Stylus Pro 7400, Service Manual

Page: 169 / 428

EPSON Stylus Pro 7400/7800/9400/9800 Revision B
Operating Principles Colorimetric Calibration (Color ID) Overview 169
2.5 Colorimetric Calibration (Color ID) Overview
This printer employs “Colorimetric Calibration (Color ID)” to correct unit-to-unit
variations in color.
“Colorimetric Calibration (Color ID)” corrects not only the weight of ink droplets
which differs according to the characteristic of individual printhead but variable factors
such as drive circuit and voltage, which provides a higher-accuracy calibration.
OVERVIEW
1. Printing/ Measuring the color of a correction pattern.
The calibration is performed by printing a correction pattern with a completed product
and measuring the color of the pattern using a calibrator.
2. Writing the correction value.
Write the correction value that was calculated from the value obtained by color
measurement to the NVRAM on the main board.
3. Reflecting the correction value.
The printer driver reads the correction value stored in the NVRAM during printing,
and correct the dot generation amount for each dot size in the print data.
Figure 2-21. Colorimetric Calibration (Color ID) Image
Printhead Main Board Supply Board
Main Unit
Variation of elements in
the drive control circuit
for printhead Variation of
reference
voltage for
individual
printhead Characteristic of
individual printhead
Colorimetric Calibration
(Color ID)
Correction of dot generation amount
Drive Control
Circuit for
Printhead
Correction of weight of
ink droplets
Printing
Result