Gestetner B147 Service Manual page 470

PROCESS CONTROL
Step 5: V , V , VL Selection and V
D B
M/A
Target
M/A
The machine determines the relationship between the amount of toner on the
transfer belt and the development bias for each of the 10 grades. The machine now
selects the development bias and charge roller voltages for the target M/A for each
color by referring to a table in memory.
The way that the laser power (V
• If it is set to 0, the LD power is fixed at the value of SP2-103-1, to -27.
• If it is set to 1, LD power is selected using the same memory table as mentioned
above.
• If it is set to 2, LD power is determined by ID sensor highlight pattern generation
(steps 6 to 8 later in this procedure).
The machine also adjusts V
development gamma detected by process control will be the value stored in SP3-
120-1 to -4 (do not adjust in the field unless advised to do so).
NOTE: The patterns on the transfer belt are cleaned by the transfer belt cleaning
unit.
Allowable changes to V
This depends on the process control type as follows.
• Forced : No limit
• Initial, After Developer Initialization: ± 80 volts
• Interval (Job End/ Non-use Time/ During Toner End Recovery): ± 40 volts
• Interval (Interrupt): Constant (The memory table is not used.)
Steps 6 to 8 are carried out only if SP3-125-2 is set to 2. (Default: Steps 6 to 8
are not used)
B147/B149/B190
Development Bias
B Development Bias
) is selected depends on the setting of SP3-125-2.
L
(toner density target) at the same time so that the
REF
, V , and V
D B
Adjustment
REF
Charge Bias
B
0
B
1
—
B
—
B C
n-1
B
n
as a result of process control:
L
6-12
LD Power
C L
0 0
C L
1 1
— —
C L
— —
L
n-1 n-1
C L
n n
B146D503.WMF
SM