Ricoh FT5233 Service Manual page 68

12 February 1992
4.8.2 V Pattern Detection
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Complete
Exiting
Paper
Fusing Exit
Sensor
Main Motor
/PTL/QL
Development
Drive CL
Charge Corona
Unit
Exposure Lamp
Erase Lamp Unit
All Blocks ON
Development
Non-image Bias
Bias
V Sensor LED
T1
T1: When the last paper is exited at the programmed copy counter for the VL
pattern detection, the V
PTL, QL, development drive clutch, erase lamp unit, development bias
continue on condition. The charge corona turns on.
T2: The exposure lamp turns on 670ms after the V
T3: The erase lamp unit changes its mode from the trail edge erase to the V
pattern erase 1527ms after the V
patterns on the drum surface. The development bias changes from the
non-image bias (about -160V) to the V
after the V pattern detection starts. The V sensor LED starts lighting
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(pulse) for the sensing Vlg and Vlp 1983ms later.
T4: The CPU takes the Vlg data 2183ms after the V
The CPU takes the Vlp data during the period between 1 and 2 in the
above timing chart.
T5: The CPU detects the Vlg and Vlp data 4 times with 833ms intervals.
T6: The charge corona output turns off 5192ms after the V
starts and all the other electrical components turn off 5470ms. This timing
difference is to reduce the remaining drum potential.
1,000 2,000
670
1527 1655 2316 2489
1794 2116 2626
2183 2622 2815 3454
1983
833
1
T2 T3 T4
pattern detection cycle starts. The main motor,
L
L
2-39
3,000 4,000
833 833
2
T5
pattern detection stars.
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pattern erase starts, making the V
pattern bias (VB0-20V) 1794ms
L
pattern detection starts.
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OPTICS
5,000
(ms)
5470
5470
5192
5120
T6
L
L
pattern detection
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