Read Sharp AR-810 (serv.man16) Service Manual online
AR-651/810 DEVELOPER UNIT 12 - 10
12. 5. 2. Operation of auto-toner sensor
(1) Functions of the auto-toner sensor
a. Initializing function: When the copier is set up or when the developer material is replaced
The automatic adjustment is made so that the output of the auto-toner sensor (input value of the
main CPU) will be 2.45 to 2.55V for the toner density of new developer material.
b. Toner density stabilizing function: During the printing operation
Through the following phases, the toner density is kept constant.
Toner consumed
촞
Toner density decreased
촞
Output change of the auto-toner sensor depending on the humidity detected
촞
Recycle toner hopper and new toner supply motor driven
촞
Toner supplied to the developer unit from the recycle toner hopper and toner cartridge
c. Toner-empty detection, release function
Toner-empty detection in the toner cartridge.
New toner supply motor driven
촞
Output of the auto-toner sensor not changed
촞
Toner density not changed
촞
Toner-empty detected
Toner-empty release
New toner supply motor driven
촞
Toner supplied from the toner cartridge
촞
Output of the auto-toner sensor changed
촞
Toner density recovering to its normal value
촞
Toner-empty released
(2) Operation of the auto-toner sensor
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
Magnetic resistance
Drive
winding
Detection
winding
DC
conversion
circuit
conversion
circuit
(Developer material)
Magnetic circuit
Auto-toner output
Main CPU
(LGC)
V
ATS
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