| 摘要 |
In a line-by-line photocopier using full and half rate scanning mirrors, rotary photoconductive drum and magnetic brush developer, contamination of the optical system is prevented by means of a substantially closed optical compartment 48 having a vertical window 54 separating lens 18 from deflecting mirror 19, filtered air being directed from a duct 43 in two directions: (a) into compartment 48 towards lamp 14 (thereby effecting cooling as well as preventing ingress of toner) and (b) downwards over the outside of window 54 (to prevent deposition of toner thereon). Suction created by a vacuum transport belt draws the downward stream of air in three paths: (a) directly, (b) via the drum and (c) via the developer housing, and also draws air from the fuser housing. <IMAGE> |
