Epson AcuLaser C8500 Service Manual page 84

EPSON AcuLaser C8500
As the number of prints increases, more toner in the developer is
consumed. In order to maintain the proper developing concentration, an
amount of toner equal to the amount consumed must be replenished from
the Toner Cartridge to the Developer Assy. This is called the "toner
dispenser." Two types of control are used for the toner dispenser: PCDC
and ADC. (For more information concerning PCDC and ADC, see 2.7.6
"Process Control" in this chapter.
In order to obtain a full color image consisting of 4 toner colors, a toner
image of each of the colors YMCB must be formed on the drum in
sequence. The full color toner image is formed by facing the various
Developer Assy's toward the drum in sequence by rotating the ROTARY
FRAME ASSY's positioned at 90( intervals on the circumference of the 4
Developer Assy's. This is referred to as "rotary developing." (For more
information on each position, see 2.7.8 "DEVE. Control" in this chapter.)
Figure 2-7. Exposure-2
Operating Principles
(
The developing charge characteristics of the developer gradually
deteriorate due to dirt on the surface produced by toner and smashing of
the surface due to mixing. Small amounts of carrier are added to the toner
in the Cartridge in order to maintain the charge characteristics, and carrier
is dispensed at the same time with toner.
Carrier collected a little at a time in a separate chamber in the Toner
Cartridge. By doing so, developer (most of which is carrier) is replaced a
little at a time, thus enabling charge characteristics to be maintained. This
is referred to as "trickle developing." Trickle developing is carried out using
the rotation of the ROTARY FRAM ASSY when rotary developing is
performed.
The mechanism if trickle developing is as follows:
1. An L-shaped pipe is inserted in the developer.
2. A small amount of developer is introduced to the pipe.
3. The developer is scooped out and goes deeper into the pipe.
4. Developer is collected in the Toner Cartridge.
Figure 2-8. Exposure-3
Revision C
2-7