HP 2200 Service Manual - Page 101

Transferring stage At the transferring stage, the toner image on the photosensitive drum's surface is moved to the paper. The transfer roller applies a positive charge to the back of the paper, causing the paper to attract the negatively charged toner on the drum's surface. The drum's small radius combined with the stiffness of the paper causes the paper to peel away from the drum. The static charge eliminator helps separate the paper from the drum by weakening the attractive forces between the negatively charged drum surface and the positively charged paper. Without this help, thin paper might wrap around the drum. The static charge eliminator also prevents droplets on the printed image at low temperature and humidity. After separation, the paper moves to the fuser station and the drum rotates to the cleaning and conditioning stations. Figure 46. Transferring the toner image on the drum Fuser stage At the fuser stage, heat and pressure fuse the toner to the paper to produce a permanent image. The paper passes between a fuser film and a pressure roller. The fuser film melts the toner while the pressure roller compresses it into the paper. To prevent the toner from dispersing during the fuser stage, this printer applies a negative dc voltage to the fuser film via the pressure roller shaft. A negative charge is applied to the surface of the paper, which improves the adhesion force of the toner particles to the paper and prevents dispersion of the toner particles. The fuser heater comes up to fuser temperature very quickly and thus does not require any power while the printer is on STBY. This feature saves power while virtually eliminating the warm-up period (less than 10 seconds). Figure 47. Fuser film and pressure roller C7058-90936 Printer functionality and operation 85