Image Transfer Current Timing - Gestetner A265 Service Manual

IMAGE TRANSFER AND PAPER SEPARATION

2.9.2 IMAGE TRANSFER CURRENT TIMING

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 supply +10µA (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,
+13µA (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 copy mode, 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 SP2-301, except for the
low transfer current.
Paper Size
A3/11" x 17",
A4/8 x 11"sideways
1/2
B4
A4/11" x 8 lengthwise,
1/2
A5/5 x 8 sidewise
1/2 1/2
A5/8 x 5 lengthwise
1/2 1/2
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. In the worst case, it may also damage the OPC drum.
A265/A267
CÓPIA NÃO CONTROLADA
Paper Tray /
By-pass Tray Duplex (2nd Side)
(Normal)
13 µA
13 µA
13 µA
15 µA
2-68
CÓPIA NÃO CONTROLADA
By-pass Tray
(Thick) / 2nd
Paper Tray
(Special Paper)
10 µA
12 µA
16 µA
16 µA
14 µA
15 µA
17 µA
20 µA
SM