Epson EPL-5700, Service Manual

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EPL-5700 Chapter2 Operating Principles
Rev. A
2-10
2.1.8 Transfer Process
2.1.8.1 Overview
This process is to transfer the toner image, which is created on the
developing process, to the OPC drum. Transfer roller is charged with
transfer bias(+3KV).
Transfer method is not the corona transfer but roller transfer method by the
transfer roller. In the roller transfer, ozone caused by corona discharge does
not occur, and chances of dislocation for the transferred image is very small,
since the paper is always sandwiched between drum and transfer roller
during printing.
The transfer current is adjusted from 6 to 10
µ
A(8
µ
A is initial value),
according to the paper type and printing duty. This can improve the
effectiveness of the transfer, especially under the high temperature with high
humidity environment. Left over electric potential on the paper is removed by
the discharge needle. Since the left toner from OPC drum attach to the
transfer roller, it is necessary to clean the transfer roller. In the cleaning, the
reversed bias(-1KVDC) is charged on the transfer roller and returns the
toner to the OPC drum. This cleaning sequence is performed with OPC
drum cleaning. Even at the cleaning of the transfer roller before printing, the
reversed bias(-1KV) is charged on the transfer roller.
OPC drum
Paper
Transfer roller
OPC drum
Paper
Transfer rolle
Re
v
e
rse
d
bi
as
(-
1
K
V
)
Tr
an
s
fer
b
ias
(3
K
V
)
Discharge Needle
Figure 2-12. Transfer Mechanism