Atdc Sensor - Minolta CF910 Service Manual

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1154SBM1104A

11-4. ATDC Sensor

• The optical ATDC Sensors (UN33, 34, 35) installed under the inner screw of the Single-

Shaft Circulation Screw detect the toner-to-carrier ratio of the developer.

• A DC negative voltage is applied to the ATDC detection surface, thereby preventing

false detection due to toner sticking to the surface. Fitted on the Single-Shaft Circulation

Screw is a seal that scrapes toner off the ATDC detection surface.

• No ATDC detection is made of the Black toner as it absorbs light.

(See 11-6. Black Toner Replenishing Control.)

Infrared light from the ATDC Sensor LED strikes the toner.

The light striking the toner reflects diffusely.

The photodiode (PD) of the ATDC Sensor receives the light reflected diffusely off the

toner. (Only the toner reflects light diffusely as carrier absorbs light.)

The ATDC Sensor converts the received light to a corresponding voltage value and

inputs it to pins 45 to 47 of IC1I on Master Board PWB-I, thus allowing the CPU to

detect the toner-to-carrier ratio.

Single-Shaft Circulation Roller

UN33, 34, 35

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