Development - Epson AcuLaser C2900N Service Manual

Chapter 6 Principles of Operation

1.3.3 Development

In the development process, toner is electrically attached to the invisible electrostatic latent image on
the drum surface to form visible toner image on the drum.
This process is performed in parallel for yellow, magenta, cyan and black color independently.
- The toner in the toner cartridge is agitated by the built-in Agitator and fed into the developer. The
Auger is driven by the toner motor.The amount of toner to be consumed according to the print
count is calculated and that amount is fed into the developer.
nism".) This is called "toner dispensation", which is controlled by two types of control, "PCDC" and
"ADC". (Refer to 5.3.2 Toner Density Control)
- In the developer section, the incoming toner is mixed with the existing developer (toner/carrier mix-
ture) by the Auger, and then supplied to the Magnet Roll located near the drum surface. The toner
and carrier are charged by friction due to agitation (toner in negative, carrier in positive), and they
attract each other electrically. The carrier, due to its magnetic properties, is attracted to the Magnet
Roll, and then uniformly leveled by the Trimmer Rod.
- The magnet roll is covered by a thin semi-conductive sleeve all over the surface. The DB (Develop-
ing Bias) voltage is supplied to this semiconductor sleeve from the High Voltage Power Supply
(HVPS). The DB voltage is negative DC voltage combined with AC voltage. The DC voltage keeps
the magnet roll at a constant negative voltage against the photoreceptor layer of the drum. There-
fore, at the area where the negative electric charge on the drum surface does not decrease, the
potential is lower than that of the magnet roll, while the potential is higher than that of the magnet
roll at the area where the negative charge on the drum surface decreases. The AC voltage shakes
the developer on the surface of the magnet roll so that the toner easily flies to the drum. Thus, only
the portions of the drum surface where the negative charge has decreased below that of the mag-
net roll (electrostatic latent image) attract the toner to form an image on the drum. Once the toner is
deposited on the drum, the potential and the toner-attracting force of the corresponding portion
decreases because the increase of negative charge lowers the potential at that portion.
Epson AcuLaser C2900N
(Refer to "Toner Dispense Mecha-
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