Samsung ML-2251N/XAA Service Manual page 35

4.4.1 HVPS (High Voltage Power Supply)
1) Transfer High Voltage (THV+)
- Input Voltage : 24 V DC ± 15%
- Output Voltage : MAX +5.0KV ± 5 %,(Duty Variable, no loading )
- Output Voltage Trigger : 6.5 uA
- Input contrast of the Voltage stability degree :under ± 5 % (fluctuating input 21.6V~26.4V)
Loading contrast : ± 5 % or less
- Output Voltage Rise Time : 100 ms Max
- Output Voltage Fall Time : 100 ms Max
- Transfer voltage range as environment varies : +650 V(Duty 10%) ~ 5 KV (Duty 90%)
- Environment Recognition : THV-PWM ACTIVE is a transfer active signal. It detects the resistance of the
- Output Voltage Control Method : Transfer Output Voltage is output and controlled by changing the Duty
2) Charge Voltage (MHV)
- Input Voltage : 24 V DC ± 15%
- Output Voltage : -1.3KV ~-1.8KV DC ± 50V
- Output Voltage Rise Time : 50 ms Max
- Output Voltage Fall Time : 50 ms Max
- Output Loading range : 30 MΩ ~1000 MΩ
- Output Control Signal (MHV-PWM): CPU is HV output when PWM is Low
3)Cleaning Voltage (THV-)
- The (+)Transfer Voltage is not output because the THV PWM is controlled with high.
- The (-)Transfer Voltage is output because the THV-Enable Signal is controlled with low
- The output fluctuation range is big because there is no Feedback control.
4) Developing Voltage (DEV)
- Input Voltage : 24 V DC ± 15%
- Output Voltage: -200V ~ -600V DC ±20V
- Output Voltage Fluctuation range: PWM Control
- Input contrast of the output stability degree :±5 % or less
Loading contrast : ± 5 % or less
- Output Voltage Rise Time : 50 ms Max
- Output Voltage Fall Time : 50 ms Max
- Output Loading range : 10MΩ ~ 1000 MΩ
- Output Control Signal (BIAS-PWM) : the CPU output is HV output when PWM is low.
5) Supply
- Output Voltage :-400 V ~-800V DC ±50 V(ZENER using,DEV )
- Input contrast of the output stability degree :under ± 5%
Loading contrast : ± 5% or less
- Output Voltage Rise Time : 50 ms Max
- Output Voltage Fall Time : 50 ms Max
- Output Loading range : 10 MΩ ~ 1000 MΩ
- Output Control Signal (BIAS-PWM) : the CPU is HV output when PWM is low.
Samsung Electronics
-1.2KV ±15% (when cleaning,200 MΩ)
transfer roller / OPC combination by applying the THV voltage (fixed value)
and then measuring the OPC voltage. This allows the resistance to be
determined. The resistance is affected by changes in temperature and
humidity. A lookup table in the control program is then used to enable the
THV voltage to be adjusted to compensate for the environmental conditions.
cycle of the THV PWM Signal. 10% Duty :+650V,90% Duty : +5KV±5%
Summary of product
Service Manual
4-15