Toner Density Control - Ricoh B286 Service Manual

! If SP2804 is set to clean the charge corona wire during warm-up, Vsp/Vsg is
measured after the wire is cleaned.
The machine measures Vsg after the machine is powered on or returns from the
!
low power mode, if SP2924 is set to "0" or "1." (The default is "0", which means
that the machine measures Vsg after power on when the fusing temperature is
below 50°C.) For more, refer to "Service Tables."
If the machine is switched off and on after the warm-up sequence when Vsg is less
!
than 2.5V, the warm-up sequence is done, and the setting of SP2924 (Warm-up
Control) is ignored.

6.6.8 TONER DENSITY CONTROL

Overview
This machine uses an ID sensor to control:
! Toner density
! Toner near end detection
! Toner end detection
The machine uses the ratio of Vsg/Vsp to find the quantity of toner that must be supplied to
the drum.
To supply toner, the machine switches on the toner supply clutch to feed toner from the
toner cartridge to the development unit.
SP3103 (ID Sensor Output Display) shows the most recent values of Vsg and Vsp that
were stored in the NVRAM (Range: 0.00 ∼ 5.00 V).
Supply Modes
There are two supply modes
! Detect Supply Mode
! Fixed Supply Mode
During normal operation, the machine uses detect supply mode.
Detect supply mode has two sub-modes (referred to as "tables").
! Main table: Used during copying
! Length table: The machine switches to this table during copying if the length of the
copy becomes more than 1189 mm (46.8").
If an ID sensor problem occurs during the job, the machine stops the end of the job. The
machine does not go into fixed supply mode automatically. The technician must repair the
machine. If the machine cannot be repaired, the technician must put the machine into fixed
supply mode with SP 2208-3.
SM 6-39
Development
B286/B289