e-STUDIO200L/202L/230/232/280/282 DEVELOPMENT SYSTEM June 2004 © TOSHIBA TEC
12 - 8
2) Function of auto-toner sensor
- The auto-toner sensor consists of the following circuits:
Drive winding:
A magnetic head (primary side) with a high-frequency magnetic field, which forms a magnetic cir-
cuit in the developer material.
Detection winding:
Receives the change in the magnetic resistance of the developer material through the magnetic
circuit (secondary side).
DC conversion circuit:
Converts a high-frequency output from the detection winding into a DC signal (auto-toner output
V
ATS
).
Fig.12-6
- When the toner density is low
The ratio of the toner against the carrier in the developer material decreases.
!"The magnetic resistance decreases.
!"The detection output increases.
!"The auto-toner output V
ATS
increases.
- When the toner density is high
The ratio of the toner against the carrier in the developer material increases.
!"The magnetic resistance increases.
!"The detection output decreases.
!"The auto-toner output V
ATS
decreases.
Drive
winding
Detection
winding
DC
conversion
circuit
Auto-toner sensor
output
To the engine-CPU
(
LGC board
)
V
ATS
Magnetic circuit
Magnetic resistance
(
Developer material
)
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