Toner Density Control - Ricoh Aficio 240W Service Manual

DEVELOPMENT

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 at 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 003.
In fixed supply mode, the machine supplies a set quantity of toner per page.
After the technician repairs the machine, the machine must be put back in detect
supply mode with SP 2208 003.
SM 6-43 B125