1. Field of the Invention
The present invention relates to a fixing device that causes a toner image on a paper to be fixed to that paper at a nip area formed between a fixing member and a pressing member, and to an image forming apparatus comprising the same.
2. Description of the Related Art
A fixing device of -an image forming apparatus generally includes a fixing roller, or a fixing belt (fixing member) wound onto the fixing roller, and a pressing roller (pressing member) that contacts the fixing member to form a nip area between itself and the fixing member. A toner image on a paper that is conveyed in is thermally fixed onto the paper in the nip area. With the fixing device, there are cases where a paper that has undergone the fixing process is discharged from the nip area while being stuck to the fixing member, and in these cases problems are caused such as paper jam.
To eliminate such problems, in a first technology for example, the fixing device is provided with a separation mechanism, which is configured so as to be capable of stripping from the fixing member the paper that has stuck to the fixing member after the fixing process. The separation mechanism has a single separation claw (separation member) that extends along the longitudinal direction of the fixing roller and that is arranged facing the fixing roller. A gap between the separation claw and the fixing roller is set to a predetermined magnitude and due to this the separation claw touches the paper that has stuck to the fixing roller and is able to strip the paper from the fixing roller.
In the first technology, a spacer that is installed near a leading edge of the separation claw is used a means for setting the gap to a predetermined magnitude. The spacer is set in position so as to abut the core of the fixing roller, and therefore a gap of the predetermined magnitude is formed between the leading edge of the separation claw and the peripheral surface of the fixing roller.
However, only a single separation claw is used in the separation mechanism of the first technology, and therefore due to unevenness in the dimensional precision of the separation claw itself, it is difficult to set the gap to the predetermined magnitude. As a result, it is difficult to strip away the paper that has stuck to the fixing roller and there is a risk that paper jam will occur.