FO-3150DE/IT/SE
On the other hand, when an area of OPC drum which was not exposed
STEP 3 (Development): Toner is attached to the latent electrostatic
to the laser beam and did not lose its charge comes in contact with the
images on the OPC drum to form visible
developing roller, any residual toner attached to the OPC drum is trans-
images.
ferred to the developing roller which is more positively charged.
As a result, unnecessary toner on the OPC drum is collected by the
developing unit.
The operating principle for that case is contrary to that for transfer of
toner from the developing roller to the OPC drum surface. (The electric
field energy direction is contrary.)
STEP 4 (Transfer): Visible images of toner on the OPC drum are trans-
ferred to the paper.
Doctor
: Toner (Negativelycharged)
Developing roller
Scraper
Toner supply roller
DC250V
100V
Aluminumlayer
(Drum base)
CGL
OPC drum
OPC drumCTL
Exposed area
(Exposedto laserbeam)Groundingsheet
DC
310V
Non-exposed area
(Not exposed to laser beam)
Paper
Aluminumlayer
(Drum base)CGL
CTL
Fig. 14
Toner is transported to the scraper area by the toner supply roller and
the developing roller. The quantity of toner to be transported to the doc-
Transfer roller
tor section is controlled by the scraper. Toner transported to the doctor
section is then passed between the developing roller and the doctor to
form a thin toner layer on the developing roller by the pressure applied
DC+3500V
by the doctor.AC600V(P-P)
When toner passes between the developing roller and the doctor, it is
charged negatively by friction.
When an area of OPC drum which was exposed to laser beam and lost
Fig. 15
its charge comes in contact with the developing roller, toner moves
from the developing roller to the OPC drum surface.The high voltage of DC+3500V plus AC600V (P-P) is applied to the
transfer roller to generate electric discharge between the roller and the
The principle of toner movement from the developing roller to the OPC
OPC drum, generating positive and negative charges. Positive charges
drum surface is as follows.
are attracted to the OPC drum and attached to the paper transported
The bias voltage of DC-310V is applied to the developing roller. Tonerbetween the transfer roller and the OPC drum. Therefore the paper has
is charged negatively by the difference (electrical energy) between thea strong positive charge.
bias voltage and the OPC drum surface potential and is attracted to the
Negatively charged toner on the OPC drum is attracted by the paper
OPC drum surface which is positively charged.
which is positively charged, and the visible images of toner are trans-
At that time, the potential of the area of the OPC drum which wasferred onto the paper.
exposed to the laser beam and lost its charge is higher than that of the
developing roller.
3 - 8 |
ACEC
