Toshiba e-studio 167 Service Manual page 204

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
Developer material Developer material
Magnetic resistance Magnetic resistance
Magnetic circuit
- 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
- 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
e-STUDIO167/207/237
DEVELOPMENT SYSTEM
Drive Detection
winding winding
increases.
ATS
decreases.
ATS
Auto-toner sensor
DC
conversion
circuit
ATS-1A
Fig. 12-5
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12 - 10
output To the A/D converter
( MAIN board )