e-STUDIO520/600/720/850 DEVELOPER UNIT March 2005 © TOSHIBA TEC
12 - 14
2) Auto-toner sensor drive 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 cir-
cuit 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 out-
put ATS-1A)
Fig.12-8
- 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 ATS-1A 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 ATS-1A decreased
Drive
winding
Detection
winding
DC
conversion
circuit
Auto-toner sensor
output
To the main-CPU
(
LGC board
)
ATS-1A
Magnetic circuit
Magnetic resistance
Developer material
To Next Page
Loading...
