9
© 2009 - 2011 TOSHIBA TEC CORPORATION All rights reserved
e-STUDIO555/655/755/855
PROCESS RELATED SECTION
9 - 5
9.4.2
Description of operation
The function and operation of each signal are as follows.
On-off signal (HVTM-0A, HVDAC-0A, HVDDC-0A, HVTT-0A, HVTBB-0A):
These signals are the on-off signals of each bias output to the main charger (main charger wire and
grid), developer bias (AC/DC), transfer belt power supply roller, and transfer belt cleaning brush. When
these signals move to a low level, the generating circuit of each bias on the high-voltage transformer
becomes on status, thus the current or voltage is output.
Reference voltage (Vctr) (HVMVR-1A, HVDVR-1A, HVTVR-1A):
These analog voltages are the reference for each output of the main charger grid, developer bias (DC)
and transfer belt power supply roller. Each output of the high-voltage transformer can be changed
linearly by changing these reference voltages.
The output procedure of the reference voltages is shown below.
• The adjusted values of the main charger bias, developer bias and transfer bias in the NVRAM are
output to the ASIC.
↓
• The data of the reference voltage is output from the ASIC to the D/A converter.
↓
• Digital-to-analog conversion at the D/A converter
↓
• The reference voltage (Vctr) of each bias is output to the high-voltage transformer.
↓
• The high-voltage transformer generates the output current or output voltage proportionate to the
reference voltage.
* The reference voltage (Vctr) can be adjusted in the Adjustment Mode (05).
* The output of the transfer belt cleaning brush was adjusted at a constant value when the high-
voltage transformer was shipped from the factory, and this adjusted value has been fixed since then.
Developer AC bias generating clock (HVTAC-0A):
This clock signal is a reference for the AC component of the developer bias.
Leak detection signal (HVTER-0):
This signal detects the abnormality (leakage) of the high-voltage transformer output. When the
abnormality is detected, the signal moves to a low level.