DRUM UNIT
SM 6-83 B234/B235/B236/D101/D102/D103
Detailed
Descriptions
4. LD PM is determined with the detected Vh: VH = (-VHref) ± 20
The development motor turns off and the laser creates a VH pattern 30 mm wide
and 80 mm long.
The laser power that creates the pattern is adjusted for the line speed.
Line Speed SP No. SP Name
Normal Speed SP2104 003 VH Pattern (Normal Speed)
Low Speed SP2104 004 VH Pattern (Low Speed)
NOTE: The laser power is set to different levels for creation of the VH pattern
and ID sensor pattern.
15 VH readings are taken at 2 ms intervals. The maximum and minimum values
are discarded. The remaining 13 readings are averaged to determine VH.
VH = VHref ±20V?
If VH = VHref ±20V is not achieved, the laser power is adjusted for creation of
the pattern.
If VH > VHref then laser power is raised 5 steps above the setting for SP2103.
If VH < VHref then laser power is lowered 5 steps below the setting for SP1203.
The VH pattern created with the adjusted laser power is sampled again. This
cycle ( and ) is repeated until a satisfactory result is achieved. If a
satisfactory result is not achieved after the 45th attempt, SC428 is issued.
The correct value for the level of the laser power (PM) is obtained. The result
can be displayed with SP3902 005. VH can be displayed with SP3902 003.
Step 5 TD Sensor Adjustment (Based on ID Sensor Readings)
The laser projects the ID sensor pattern onto the drum.
The ID sensor reads the patterns and obtains a value for Vsp (covered area of the
pattern) and a value for Vsg (bare surface of the drum in the pattern).
The machine takes these values and calculates a new value for Vref (Vref =
Vsp/Vsg). The voltage that was used to make the sensor pattern can be displayed
with SP3902 006.
Step 6 Update Vb, Vg (Based on VL Detection)
Vb (Development Bias Voltage) and Vg (Charge Grid Voltage) are finally updated.
Step 7 Process Control Ends
All motors shut off in the same sequence as any job end.
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