Service manual

(2) ACC Test Pattern
The IPU board firmware has a test pattern that has eight 10-step gradation
scales for each color (BKCMY) for Letter mode and Photo mode.
–ACC (Auto Color Calibration)–
This machine automatically calibrates the printer gamma curve when the
user selects ACC.
When ACC is activated, the machine prints out an ACC Test Pattern. After
the user puts the test pattern on the exposure glass correctly, the machine
scans the test pattern and corrects the printer gamma by comparing the
ideal settings with the current image density.
The machine scans eight lines, one for each color (BKCMY) in letter mode,
and one for each color in photo mode.
After performing ACC, the machine resets the settings of the offset for each
color in High, Middle, and Low ID to the default (15). The machine calculates
the actual ID max based on data from the ACC scan.
The corrected printer gamma curves can be adjusted further using SP mode,
as discussed on the prevous page (Refer to section 5, Replacement and
Adjustment, Copy Image Adjustment).
It is important to note that ACC is intended to provide a "rough" adjustment
or a "starting point" for the calibration process. ACC also allows a customer
to set gamma settings to a "reasonably acceptable" standard, however,
manual adjustment of gamma settings by a service representative will
provide optimal copy quality.
Rev. 1/97
IMAGE PROCESSING
A166/A187/A189 2-60 SM
CÓPIA NÃO CONTROLADA
CÓPIA NÃO CONTROLADA