Epson Stylus Photo R800 - Page 18

EPSON Stylus Photo R800 Revision A
OPERATING PRINCIPLES Printer Mechanism 19
 Off-range restriction control
At the time of frameless printing, a paper leading edge is detected using
the PW Sensor to restrict the frameless off-range amount.
 Complete frameless mode
Control is performed to print the print data 3mm larger at top, 5mm
larger at bottom, and 2.5mm lager at left and right than the detected
paper size.
 Roll paper mode
In the left and right frameless mode, control is performed to print the
print data 2.5mm lager at left and right than the detected paper size.
 PW sensor dark voltage (VH) measurement
PW sensor dark voltage (VH) measurement is performed at the following
timings and locations and used to calculate the threshold value of whether
paper is present or not.
 Cut sheets, Roll paper
The dark voltage is measured and updated at every power-on, and the
threshold value (VS) is calculated and saved in the EPROM area as a
PW detection level.
• Threshold value > detection voltage: Paper present
• Threshold value < detection voltage: Paper absent
 CD-R Tray
When a CD-R is used, the dark voltage is measured on the CD-R tray,
and the threshold value (VS) is then calculated and saved in the
EPROM area as a PW detection level.
• Threshold value > detection voltage: CD-R present
(tray home position detected)
The measurement voltage in the presence of the CD-R is saved into
the EEPROM as a white level. The white level value is used to check
the sensor deterioration condition during servicing or like.
• If the measurement value of the white level is close to that of the PW
detection level, it means that the sensor is dirty or deteriorated.
2.2.1.4 APG (Auto PG) Mechanism
The following indicates the APG DC motor specifications.
The APG Motor (DC Motor) and two APG Sensors automatically adjust the PG
amount according to the paper.
Figure 2-2. APG Mechanism
Table 2-3. APG Motor Specifications
Item Specifications
Type DC motor with brushes
Drive voltage +42V ± 5% (voltage applied to driver)
Winding resistance 64.7Ω ± 15%
Inductance 37.6mH ± 25%
Drive method PWM, constant-current chopping
Drive IC A6615
Carriage Shaft
Carriage Unit
APG Motor
PG Cam
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