Development - KIP 9000 Service Manual

3. 2. 5

Development

The Developer Roller is evenly covered with the toner, and it is contacted to the Drum firmly. (The
width of contacting area is about 5mm.) The Developer Roller is supplied with -YV of Developer
Bias which is flexibly adjusted by the Auto Density Control. On the other hand, an Electrostatic
Latent Image consisting of -XV area and -YV area exists on the Drum. The relationship among -XV,
-YV and the exposed part of the Drum (about -50V) are as follows.
-XV (White image area of Drum) < -YV (Developer Bias) < -50V (Black image area of Drum)
Seen from the voltage of Developer Roller Bias (-YV), the -50V area on the Drum that was
exposed to the light from the LED is relatively "positive", so the toner moves from the Developer
Roller to the -50V area of Drum. On the other hand, the -XV area is relatively "negative" seen from
the Developer Roller, so the toner does not move to the -XV area but stays on the Developer
Roller. A visible toner image is formed on the Drum as a result.
The value of Developer Bias "-YV" is not constant. The Auto Density Control automatically
changes the Developer Bias to the most appropriate level according to the information from the
Density Sensor. (Refer to [3.4.1 Auto Density Control] on page 3-23 for more detail.)
Drum
Drum
-50V
-YV
-XV
Developer Roller
Developer Roller Density Sensor
Before Development After Development
(Toner moves only to -50V area)
-50V -XV
(Invisible Electrostatic Latent Image) (Visible toner image)
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