HP Pro 4300 C9H70UT C9H70UT#ABA manual Q2431-90912 Theory of operation

Cleaning the transfer charging roller and photosensitive drum

Residual (left over) toner is cleaned off of the transfer charging roller and photosensitive drum so that subsequent images are crisp and clear. Because not all of the toner is attracted to the media when the image is transferred from the drum, some toner remains on the drum. Toner may also remain on the transfer roller if a jam occurs and the transfer of toner to the media operation is not completed.

A dc negative bias (charge) is applied to the transfer charging roller opposite the photosensitive drum, which causes the residual toner to be attracted to the drum.

A cleaning blade is in contact with the surface of the drum at all times. As the drum rotates during printing, excess toner from the transfer charging roller and drum are scraped off and stored in the waste-toner receptacle.

Cleaning the transfer charging roller

Transfer charging roller

Residual toner

Cleaning the photosensitive drum

Waste toner compartment

Cleaning blade

Figure 56. Cleaning the transfer charging roller and photosensitive drum

Q2431-90912 Chapter 5 Theory of operation 125