Xerox WorkCentre 385, Service Manual

Page: 181 / 184

H.V.P.S (High Voltage Power Supply)
12/98
7 - 47
WorkCentre 385
H.V.P.S (High Voltage Power Supply)
Output Specifications
Transfer High Voltage(THV)
THV output is a series circuit of positive and negative voltage generation part.
Negative output is for cleaning the OPC Drum and positive output is for
transferring the Toner on the paper. High voltage is generated by DC-DC
Converter that is composed of a PWM Control Circuit, a Blocking Oscillator and
4 times voltage rectifying circuit. the “THV-EA” goes to “low” positive and
negative parts operate. And this state, THV positive output is controlled by
“THV-PWM” duty cycle, when it goes to “High”, positive part outputs 0V, and
negative part only output -1000V. When some duty cycle is applied to the PWM
input of H.V. circuit, THV terminal outputs positive voltage.
Main and Bias High Voltage
(MHV,SUPPLY,DEV)
MHV generation part is composed of blocking oscillator and double voltage
rectifying circuit. When “MHV-EA” signal goes to “High”, the MHV outputs, and
this state, when “SUPPLY-EA” or “DEV-EA” input goes to “Low”, SUPPLY or
DEV terminal corresponding it outputs the voltage that is generated by dropping
MHV. DEV output voltage is selectable 300V or 350V.
Item
Printing/
Initial
DCU On
Supply Voltage -500V -500V
Bias Voltage -300V -300V
THV(Transfer High Voltage) (-) -1KV -1KV
THV(Transfer High Voltage) (+) 0V 0V
MHV(Main High Voltage) -1.4KV -1.4KV
www.printcopy.info
www.printcopy.info