2–3COPYING PROCESSCOPYRIGHT © 1998 CANON INC. CANON NP6621 REV.0 FEB. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)C. Step 1 (pre-exposure)Figure 2-105Before primary charging takes place, the light ofthe pre-exposure lamp is directed to the photosen-sitive drum to eliminate the residual charges on thedrum, thereby preventing uneven density.D. Step 2 (primary charging)Figure 2-106The copier uses what is termedprimary charg-ing, in which a charging roller made of conductingmaterial directly charges the photosensitive drum.Compared to the conventional corona chargingmethod, direct charging provides such advantagesas a low application voltage and virtual absence ofozone.The primary charging roller is a special rollerand possesses different characteristics from thetransfer roller. yyyyyyyyyyyyzzzzzzzzz{{{{{{{{{{{{{{{{||||||||||||Pre-exposure lampPrimary charging roller
