Epson AcuLaser C2600 Service Manual page 129

EPSON AcuLaser C2600/2600
2.5.2.2 Registration Control
This controls the rotating speed of the photoconductor drum when the laser beam
"draws" an electrostatic image on it in order to prevent the print from being out of
color registration. As the laser draws the image for each color by turns in the color
mode, the intervals of lines drawn by the laser in sub-scanning direction may vary by
each color due to the drum's variation in speed. To prevent this from occurring, the
printer performs the following operations:
1. Measuring a rotation period of the Transfer Belt
Rotates the transfer belt on several conditions and detects the Vsync detection
portion to obtain the rotation period of the belt. The correction value is calculated
based on the obtained value.
2. Obtaining synchronization margin of error for Hsync
Calculates the synchronization error time between the Vsync signal and Hsync
signal. The margin of error obtained from the calculation is used to calculate a
value to control the Hsync.
3. Setting the value to control the Photoconductor drive motor
Calculates and sets the controlled variable in value to control the speed of the
photoconductor drive motor based on the correction value obtained from the above
procedures.
Operating Principle
2.5.2.3 Transfer Bias Control
This control is performed to change the transfer bias depending on the ambient
temperature and the type of paper in order to provide stable print quality.
JUDGING THE TEMPERATURE AND HUMIDITY
The temperature and humidity detected by the temperature and humidity sensor are
classified to eight and five stages for temperature and humidity respectively. This
creates a bias determination table consisting of eight columns for temperature level by
five rows for humidity level, which determines the transfer bias in accordance with the
conditions such as paper type.
PRIMARY TRANSFER BIAS
The primary transfer bias is set depending on the factors below.
Temperature level
Humidity level
Table 2-8. Primary Transfer Bias value Determination Table
1
a
0
i
1
q
2
y
3
G
4
Control
Temperature Level
2 3 4 5 6 7
b c d e f g
j k l m n o
r s t u v w
z A B C D E
H I J K L M
Revision B
8
h
p
x
F
N
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