Toshiba e-STUDIO281c Service Manual page 280

2) Functions of the color auto-toner sensor
- Initializing function: When unpacking or replacing developer material
This sensor automatically adjusts the light amount of sensor to make the detected value of toner
density of new developer material by auto-toner sensor equal to the fixed value. Also, the
detected value by the reference plate is stored in memory after this adjustment.
- Toner density stabilizing function:
The difference between the toner density on the sleeve and the toner density at the initialization
mentioned above is detected. Then the difference is adjusted to maintain the density at a certain
level.
The detected value of auto-toner sensor is corrected in comparison with the detected value by
the reference plate not to be affected with temperature, stain and deterioration.
Through the following phases, the toner density is kept constant.
Toner is consumed.
→ Toner density decreases.
→ Output change of the auto-toner sensor is detected at the preceding position to the develop-
ing position.
→ Drives the developer motor at the developing position.
→ Drives the color developer toner supply clutch.
→ Supplies the toner for a specified period of time.
→ The same procedure is repeated for other two colors.
- Toner-empty detection/clear function:
Detects toner being empty in the toner cartridge.
Drives toner motor.
→ Output of the auto-toner sensor is not changed.
→ Toner density is not changed.
→ Detects toner being empty (Toner-empty detection function).
Clears toner-empty.
Drives toner motor.
→ Supplies toner from the toner cartridge.
→ Output of the auto-toner sensor is changed.
→ Toner density recovers to its normal value.
→ "Toner-empty" is cleared. (Toner-empty clear function)
3) Operations of the color auto-toner sensor
When the toner density is low:
Toner ratio to the carrier in the developer material decreases.
→ The light reflection amount decreases.
→ Detection output (voltage) decreases.
When the toner density is high:
Toner ratio to the carrier in the developer material increases.
→ The light reflection amount increases.
→ Detection output (voltage) increases.
e-STUDIO281c/351c/451c DEVELOPER UNIT
12 - 12
June 2005 © TOSHIBA TEC