17 January, 2003 PROCESS CONTROL
6-13
Detailed
Descriptions
Step 5: VD, VB, VL Selection and VREF Adjustment
The machine determines the relationship between the amount of toner on the
transfer belt and the development bias for each of the 5 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
L) is selected depends on the setting of SP3-125-2.
• 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
REF (toner density target) at the same time so that the
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).
After that, the transfer belt cleaning unit cleans the transfer belt.
Allowable changes to VD, VB, and VL as a result of process control:
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)
Target
M/A
M/A
B Development Bias
Development Bias Charge Bias LD Power
B0 C0 L0
B1 C1 L1
———
B C L
———
B
n-1
C
n-1
L
n-1
Bn Cn Ln
G080D938.WMF
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