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b.
PRCB Output signals
(1) γ LED CONT, γ CONT (PRCB to TCSB)
ON/OFF control signal for gradation detection
LED.
[L]: LED ON
[H]: LED OFF
(2) γ Dmax LED Vref, Vref (PRCB to TCSB)
Power supply line to the γ LED on the TCSB.
The voltage applied to the γ LED is adjusted so
that the γ MONI signal becomes 4.5V.
[8] Dot Diameter Correction Control
/Dmax LED Vref
LED CONT
SIG/MONI
PRCB
Dot diameter is detected by TCSB (toner control sen-
sor board) and controlled by PRCB (printer control
board).
1. Operation
Dot diameter correction is performed to prevent
the fluctuation of 1 dot laser beam in diameter
due to a soil in the writing unit or a change of
developing ability.
(1) Method
Creates several same condensation dot pattern
patches changing the laser power and reads
them with γ sensor (PD2). Uses the laser power
where the γ sensor output reaches reference
voltage as MPC.
(2) Timing
a) At the end of job after every 20,000 copies.
2-G-7
DEVELOPING UNIT
5VDC
TCSB
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