Toshiba e-STUDIO2500c Service Manual page 266

[ 2-2 ] Auto-toner sensor control circuit
The auto-toner sensor is composed of the following circuits.
• Drive winding:
Magnetic head (primary side) with a high-frequency magnetic field, which forms a magnetic circuit in
the developer material
• Detection winding:
Receiving the changes in the magnetic resistance of the developer material via a magnetic circuit
(secondary side)
• DC conversion circuit:
• Converting the high-frequency output from the detection winding to a DC signal (auto-toner output
ATSN)
Developer material Developer material
Magnetic resistance Magnetic resistance
Magnetic circuit
• When the toner density is low:
Toner ratio to the carrier in the developer material decreased
→ Magnetic resistance decreased
→ Detection output increased
→ Auto-toner output ATSN increased
• When the toner density is high:
Toner ratio to the carrier in the developer material increased
→ Magnetic resistance increased
→ Detection output decreased
→ Auto-toner output ATSN decreased
e-STUDIO2500c/3500c/3510c DEVELOPER UNIT
Drive Detection
winding winding
Auto-toner sensor
DC
conversion
circuit
ATSN
Fig. 12-7
12 - 10
output
To the Engine CPU
( LGC board )
May 2006 © TOSHIBA TEC