1 October, 1999
IMAGE TRANSFER AND PAPER SEPARATION
2-35
Detailed
Descriptions
2.7.2 IMAGE TRANSFER MECHANISM
There are two transfer current levels: low transfer current level and high transfer
current level. The image transfer procedure is as follows:
1. When the CPU receives the image writing start signal, the CPU instructs the
high voltage supply board to 10
µ
A (low transfer current level) to the
roller. This prevents any positively charged toner on the drum surface from
transferring to the transfer roller.
2. At a certain time after the low transfer current has been supplied to the roller,
+13
µ
A (paper fed from the paper tray) is applied to the roller to transfer the
toner to the paper.
3. After the trailing edge of the paper has passed through the roller, transfer
current turns off. In multiple printing, the transfer current shifts again to the low
transfer current.
The default transfer roller current (high transfer current level) is as shown in the
following table. The transfer current can be adjusted using the printer service
mode, except for the low transfer current.
Paper Size
Paper Tray
Duplex
By-pass Tray /
2nd Paper Tray
(Special Paper)
A3/11" x 17",
A4/8
1/2
x 11" SEF
13
µ
A
10
µ
A
14
µ
A
B4
13
µ
A
12
µ
A
15
µ
A
A4/11" x 8
1/2
LEF,
A5/5
1/2
x 8
1/2
SEF
13
µ
A
16
µ
A
17
µ
A
A5/8
1/2
x 5
1/2
LEF
15
µ
A
16
µ
A
20
µ
A
Be careful when increasing the transfer current. This might cause a ghosting effect,
in which part of the image at the top of the page is repeated lower down the page
at a lower density. It may also damage the OPC drum in the worst case.
