Toshiba e-STUDIO2500c Service Manual page 238

[ 2 ] Description of operation
The function and operation of each signal are as follows.
• On-off signal (HVTMC/K, HVTDACC/K, HVTDDCC/K, HVTTR1Y/M/C/K, HVTTR2, HVTECC/K):
These signals are the on-off signals of each output to the main charger (needle electrode and grid),
developer bias (AC/DC), 1st transfer bias (1st transfer roller), 2nd transfer bias (2nd transfer facing
roller) and cleaner bias (recovery blade). When these signals move to a low level, the generating cir-
cuit of each bias on the high-voltage transformer becomes ON status, thus the current or voltage is
output.
• Reference voltage (HVTMVRY/M/C/K, HVTDVRY/M/C/K, HVTTR1VRY/M/C/K, HVTTR2VR):
These analog voltages are the reference for each output of the main charger grid, developer bias
(DC),1st transfer bias and 2nd transfer bias. 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 of each bias is output to the generating circuit of each bias.
↓
- The circuit of each bias generates the output current or output voltage proportionate to the refer-
ence voltage.
* The reference voltage can be adjusted in the Adjustment Mode (05).
• Developer AC bias generating clock (HVTDACK):
This clock signal is a reference for the AC component of the developer bias.
• Leak detection signal (HVTSTS):
This signal detects the abnormality (leakage) of the high-voltage transformer output. When the
abnormality is detected, the signal moves to a low level.
e-STUDIO2500c/3500c/3510c PROCESS UNIT RELATED SECTION
11 - 6
May 2006 © TOSHIBA TEC