Toshiba e-studio550 Service Manual page 153

10. 4. High-voltage Transformer Output Control Circuit
10. 4. 1. General description
The high-voltage transformer output control circuit is a circuit that generates the output control voltage
(Vc) for the main charger (Main), transfer belt power supply roller (Transfer), drum cleaning brush
(Brush) and developer bias (Developer).
It changes the output current lineary by changing the Vc.
10. 4. 2. Operation
PWA-F-LGC-340/341/342
Adjustment
BC-RAM
mode
IC27
• Each adjustment value of the Main, Transfer and Developer in the BC-RAM is output to the main
CPU.
• The Vc data is output to the D/A converter from the main CPU.
• The data is converted into the analog data at the D/A converter.
• The Vc is output to the Main, Transfer, and Developer transformer.
• The Main, Transfer, and Developer transformer generate an output current or voltage which is
proportional to the Vc.
* The adjustment of the Vc (changing of the adjusted data) is carried out at the adjustment mode.
* The output value of the drum cleaning brush bias is fixed when the high-voltage transformer is
delivered to the market.
e-STUDIO550/650/810 PROCESS RELATED SECTION
Gate
Main CPU
array
IC58 IC56
10 - 4
Digital Analog
data data
D/A
conerter
IC18
PS-HVT-340
Main
Vc
Output
Transfer
Developer
JUNE 2002 © TOSHIBA TEC