In the prior art, a fuser or fixation unit usually fixes a toner image on an image-transfer sheet of paper by fusing rollers that have been heated. In the above fuser, since toner is not completely fixed on the transfer sheet, some toner remains on the fusing rollers. This remaining toner is also so called residual toner. The residual toner is collected from the fusing rollers by cleaning rollers via pressure rollers.
An image-transfer sheet is soiled by the residual toner in a prior art fuser. As described above, a portion of toner on the image-transfer paper becomes unfixed, and the residual toner is attached to a fuser separation pawl that separates the transfer paper from the fuser rollers. As the residual toner increases beyond a certain amount on the fuser separation pawl, aggregated toner falls from the fuser separation pawl and smears the transfer paper. Thus, the fuser separation pawl needs to be maintained. While the fuser separation pawl is periodically cleaned or replaced, the image forming device is not available.
For the above prior art problems, prior art techniques had attempted to minimize the undesirable effects. Japanese Patent Publication 2000-75750 discloses a cleaning blade for removing adherents such as toner from the cleaning rollers as well as a ceramic heater for heating the cleaning blade beyond a melting temperature of the residual toner. The ceramic heater adds structural complexities and requires additional costs. In relation to the prior art cleaning technologies of a fuser, Japanese Patent Publication Hei 7-104602 also discloses techniques for increasing the cleaning efficiency for the cleaning material in the fusing rollers in an image forming device and for uniformly applying oil. Although the cleaning rollers are located on the transfer paper outlet side of the fusing rollers, the residual toner that has been cleaned by the cleaning rollers falls off onto the transfer sheet for undesirable effects.
It remains desirable to maintain the fuser rollers substantially free from residual toner without significant structural modifications to the fuser or fixing unit.