EPSON Stylus Pro 4400/4450/4800/4880/4880C Revision C
Operating Principles Printer Mechanism Components 150
 Fine Adjustment Pattern
This is a pattern for calculating the exact correction value. It uses all nozzles 
and 3 Bi-D patterns are printed after being shifted by 1/1440 step for each 
color. The location detected with the most raised A/D values and the 2 
locations detected with the most lowered A/D values are averaged, and the 
averaged values of the 3 patterns are calculated again, with the resulting value 
set as the correction value.
Correction Value = {(A1+B2+C3/3) + (A2+B2+C2/3) + (A3+B3+C3/3)} / 3
Figure 2-59. Fine Adjustment Pattern Detection
A/D 
Value
Scanning Position
Most A/D values 
are high
Adjustment Lines Standard Lines
Most A/D values 
are low