Brother International HL-4000CN Service Manual - Page 84

1.3.4 Primary transfer (drum -> IDT 1) In the primary transfer process, toner image formed on the drum surface is transferred onto the surface of the IDT 1 (Intermediate Drum Transfer 1: intermediate transfer roll 1). Two IDT 1 are provided: yellow and magenta, and cyan and black are respectively transferred to their IDT 1. • IDT 1 is a conductive roll and receives supply of high positive voltage from HVPS. The toner image (negatively charged) on the drum is attracted to the IDT1 positively charged, and transferred from the drum to the IDT1 surface. At this time, electric charge of the drum surface is neutralized by the IDT1. Drum surface 40 :O : Negative electric charge Positive electric charge O : Toner Fig.3-16 Drum () ++ + + + + IDT1 + + + + Drum (M) + Drum (C) ++ + + + + + 0IDT1 + + + Drum (K) + HVPS Fig.3-15 III-9