Image Transfer Current Timing - Ricoh B121 Service Manual

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6.12.2 IMAGE TRANSFER CURRENT TIMING

There are two transfer current levels: low and high. 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,

high transfer current is applied to the roller to transfer the toner to the paper

(see the table below).

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 high transfer current levels (default) are as shown in the following table. With

SP2-301, the high transfer current level used for the paper feed trays, duplex tray,

by-pass tray, and cleaning an be adjusted.

By-pass Tray

card/Envelope

Be careful when increasing the transfer current. This may 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.

IMAGE TRANSFER AND PAPER SEPARATION

By-pass Tray

B121 Series/B259 Series

Table of Contents

B259 B260 B261 B122 B123