HP Pro 4300 C9H70UT C9H70UT#ABA manual Fusing the image

Fusing the image

The image is only held in place by electrostatic attraction when it is transferred from the drum to the media. The lightest touch will smear it. During the fusing process, heat and pressure fuse the image to the media to produce a permanent image. The media passes between a heated fusing roller and a soft pressure roller. This melts the toner and presses it into the media.

This printer utilizes an on-demand fusing method. This method has fast temperature-rising time, which shortens the wait time (the time it takes to heat the fuser to its operating temperature). It is not necessary to supply power to the fuser heater during the standby mode which conserves energy.

For the HP LaserJet 4200, a dc negative bias (charge) is applied to the fixing film. This stabilizes the toner so that it does not scatter the toner over the media and produce a blurred image.

For the HP LaserJet 4300, a dc negative bias (charge) is applied to the fixing film and a dc positive bias (charge) is applied to the pressure roller. This stabilizes the toner so that it does not scatter the toner over the media and produce a blurred image.

To prevent offset images, the surface of the fixing film is coated with fluorine for both printer models.

Figure 55. Fusing the image

124 Theory of operation Q2431-90912