Epson AcuLaser C3000 Series, Service Manual

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EPSON AcuLaser C4000/C4100/C3000 Revision F
Operating Principles Control 2-87
2.8.5 Color Registration Control
This printer uses a dedicated drum and developer for each of the colors yellow,
magenta, cyan and black. Images are formed on each drum, and when they
are layered on top of each other, some gaps in the quantity needed for each
color can occur. To avoid this, Color Registration Control calculates the
registration gaps and adjusts the timing of writing from the ROS.
An overview of Color Registration Controls shown below.
1) SENSOR ASSY ADC (PL6.1.11) output is measured when there is no
toner on the BTR, and the threshold is established.
2) A Color Registration Control patch is formed on the BTR surface. The
patch consists of a leading black trigger followed by 10mm lines of color
in K, C, K, M, K, Y order, repeated four times.
Figure 2-36. Color Registration Control
3) The density of the formed patch is read by the SENSOR ASSY ADC.
4) The registration gap adjustment quantity is calculated according to the
threshold established at 1) and the patch density measured at 3).
5) The ROS write timing is adjusted according to the registration gap
adjustment quantity.
C H E C K
P O I N T
The Color Registration Control explained in this section
makes adjustments to avoid color gaps in the secondary
scan direction (paper transport direction). During process
control, adjustments are made according to moment by
moment changes in printer internal temperature and
number of print pages. Because control is based on
conditions in the printer, adjustment by manual operation is
not possible. To avoid color gaps in the primary scan
direction that are not influenced by the printer's internal
conditions, make adjustments from the control panel.
(Refer to Chapter 6.6.5 "Color Registration Adjustment")