Development - Epson AcuLaser C2800 Service Manual

AcuLaser C2800/C2800D/C3800/C3800D

2.3.3 Development

In development process, toner is electrically applied to the invisible electrostatic latent
image on the drum to form a visible image on it. This process is performed
simultaneously for each of the yellow, magenta, cyan and black colors.
Toner in the toner cartridge is stirred by Agitators, and is supplied to the Deve
Assy. Auger is driven by the Sub Motor and the Deve Motor in the DRIVE ASSY
MAIN. The amount of toner transferred to the Deve Assy is calculated based on
the number of printed pages. This is called "toner dispensation" and is controlled
by "PCDC" and "ADC".
(Refer to "2.7.3.2 Toner Density Control (p63)
Toner transferred to the Deve Assy and developer (toner and carrier) in the Deve
Assy is stirred by the Augers, and are supplied to the Magnet Roll located near the
drum surface. The toner and the carrier are charged by the triboelectricity (toner:
negative, carrier: positive), and they are attracted to each other.
As the carrier is a magnetic body, it is attracted to the magnetized Magnet Roll,
and a uniform layer of carrier is formed on the Magnet Roll by passing through the
Timmer Rod.
The surface of the Magnet Roll is covered with the conductive sleeve. The DB
(Developing Bias) is supplied to the conductive sleeve from the HVPS. The DB
voltage is a negative DC voltage that AC voltage is superimposed on it. The
electrostatic latent image on the drum, the area hit by the laser, carries less
negative charges than the other area on the drum. As the uniform negative charge
on the Magnet Roll is kept at a certain level by the DC voltage, the potential
difference between the Magnet Roll and the drum surface becomes as follows; the
electrostatic image area is higher than the Magnet Roll, and the other area is lower
than the Magnet Roll. The superimposed AC voltage vibrates the carrier on the
Magnet Roll surface making it easier for toner to jump to the drum. Thus, the
negatively charged toner on the Magnet Roll is only attracted to the electrostatic
latent image and forms a toner image on the drum. Once the toner adheres to the
image area on the drum, no more toner is attracted to the area as negative charges
of the area are increased.
OPERATING PRINCIPLES
".)
Technical Explanation of Print Process
Figure 2-6. Development
Revision C
35
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