Toshiba e-studio212 - Page 194

e-STUDIO182/212/242 © 2009 TOSHIBA TEC CORPORATION All rights reserved
DEVELOPMENT SYSTEM
11 - 10
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
circuit 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. 11-5
- 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.
Developer material
Magnetic resistance
Drive
winding
Detection
winding
DC
conversion
circuit
Auto-toner sensor
output
To the A/D converter
(
MAIN board
)
ATS-1A
Magnetic circuit
Magnetic resistance
Developer material