Service Manual

DEVELOPING UNIT
2-16
II UNIT EXPLANATION
4.2 Operation
4.2.1 Developing control
For details of each operation timing of developing, see “3. Drum section”.
4.2.2 Control of toner density in the developing unit
The TDS (Toner density sensor) uses the L detection method (detection of permeability in developing
materials) to detect the toner density of developing materials. The value thus obtained is compared with
the standard value of the toner density for the L detection adjustment that is recorded in the PCU con-
tained in the CB (Main body control board) to see if toner should be supplied or not. (For details of toner
supply, see “5. Toner supply/cleaning/recycling section”.)