Xerox 3300MFP Service Manual - Page 70

Theory of Operation SMPS & HVPS board The SMPS supplies DC Power to the System. It takes 110 V/220 V and outputs the +5 V, +24 V to supply the power to the Control Board. The HVPS board creates the high voltage of THV/MHV/Supply/Dev and supplies it to the print cartridge for making best condition to display the image. The HVPS takes the 24 V and outputs the high voltage for THV/MHV/BIAS, and the high voltage output is supplied to the toner, OPC cartridge, and transfer roller. 1) HVPS (High Voltage Power Supply) ■ Transfer High Voltage (THV+) ■ Input Voltage: 24 V DC ± 15% ■ Output Voltage: MAX +5.0 KV ± 5%, (Duty Variable, no loading) -> 1.2 KV ± 15% (when cleaning, 200 ΜΩ) ■ Output Voltage Trigger: 6.5 µΑ ■ Input contrast of the Voltage stability degree: under ± 5% (fluctuating input 21.6 V - 26.4 V) Loading contrast: ± 5% or less ■ Output Voltage Rising Time: 100 ms Max ■ Output Voltage Falling Time: 100 ms Max ■ Fluctuating transfer voltage with environmental various: +650 V (Duty 10%) ~ 5 KV (Duty 90%) ■ Environment Recognition Control Method: The THV-PWM ACTIVE is transfer active signal. It detects the resistance by recognizing the voltage value, F/B, while permits the environmental recognition voltage. ■ Output Voltage Control Method: Transfer Output Voltage is outputted and controlled by changing Duty of THVPWM Signal. 10% Duty: +650 V, 90% Duty: +5 KV ± 5% ■ Charge Voltage (MHV) ■ Input Voltage: 24 V DC ± 15% ■ Output Voltage: -1.3 KV ~ -1.8 KV DC ± 50 V ■ Output Voltage Rising Time: 50 ms Max ■ Output Voltage Falling Time: 50 ms Max ■ Output Loading range: 30 ΜΩ ~ 1000 ΜΩ ■ Output Control Signal (MHV-PWM): CPU is HV output when PWM is Low ■ Cleaning Voltage (THV-) ■ The (+) Transfer Voltage is not outputted because the THV PWM is controlled with high. ■ The (-) Transfer Voltage is outputted because the THV-Enable Signal is controlled with low. ■ The output fluctuation range is big because there is no Feedback control. ■ Developing Voltage (DEV) 2-28 Phaser 3300MFP Service Manual