Development - Epson ColorPage EPL-C8200 Service Manual

EPSON ColorPage EPL-C8200

2.1.3.3 (3) Development

In the development step, toner particles are attracted to the invisible
electrostatic latent image on the drum surface to form a visible toner
image.


This printer employs the rotary and trickle development methods. In
rotary development, four Developer Assemblies rotate in sequence;
trickle development uses developer consisting of carrier and toner.
The developer in the Developer Assembly is agitated by the Auger.
(The auger is a spiral agitator.) The developer is sent to the Magnet
Roll near the surface of the drum. The toner particles and carrier
particles (that make up the developer) are charged by agitation;
toner particles are negatively charged, carrier particles are positively
charged and thus electrically attracted each other. The carrier
particles are magnetic and are attracted to the Magnet Roll
(magnetized). The carrier particles go through the Trimmer Blade,
resulting in a uniform carrier layer.
The Magnet Roll surface is covered with a thin semiconductive
sleeve. The HVPS applies the DB (Developing Bias) voltage to this
sleeve. The DB voltage is negative DC voltage to which AC voltage
has been superimposed. Using this DC voltage, the Magnet Roll
retains constant negative voltage on the photoconductive layer of
the drum. As a result, areas where negative potential on the drum
surface has not been decreased have lower electric potential than
the Magnet Roll; areas where negative potential has been
decreased have higher electric potential. The AC voltage shakes
developer onto the Magnet Roll so that it is easy for the toner
particles to be attracted to the drum surface.
The negatively charged toner particles are attracted only toward
areas where negative potential on the drum surface has decreased,
thus forming a toner image on the drum surface. When the toner
particles adhere to the drum surface, the negative potential at that
area where the toner particles are adhering decreases, resulting in a
decrease in force in attracting toner particles to that area.
Chapter 2 Operating Principles
Bias
Figure 2-6. Development (1)
Revision A
2-5