Fixing unit and image forming apparatus having the same

A fixing apparatus for fixing an image onto an image bearing member comprising:

• means for heating an image bearing member, having an image thereon, at a predetermined temperature;
• means for selecting a mode between a usual mode and a preheat mode;
• means for keeping the heating means at a first temperature in the usual mode, and for keeping the heating means at a second temperature which, is lower than the first temperature, in the preheat mode;
• means, which is movable between a first position brought into contact with the heating means and a second position separated from the heating means, for pressing the image bearing member against the heating means at the first position;
• means for moving the pressing means between the first position and the second position;
• means for controlling the moving means to move the pressing means from the first position to the second position when the preheat mode is selected by the selecting means, and to move the pressing means from the second position to the first position when the usual mode is selected by the selecting means;
• and
• means for rotating the pressing means when the pressing means is located at the second position.

An image forming apparatus comprising:

• means for forming an electrostatic image on an image bearing body;
• means for developing the image by supplying a developing member to the electrostatic image;
• means for transferring the developed image from the image bearing body to a sheet;
• means for heating the sheet, having the image transferred by the transferring means thereon, at a predetermined temperature;
• means for selecting a mode between a usual mode and a preheat mode;
• means for keeping the heating means at a first temperature in the usual mode, and for keeping the heating means at a second temperature which, is lower than the first temperature, in the preheat mode;
• means, which is movable between a first position brought into contact with the heating means and a second position separated from the heating means, for pressing the image bearing member against the heating means at the first position;
• means for moving the pressing means between the first position and the second position;
• means for controlling the moving means to move the pressing means from the first position to the second position when the preheat mode is selected by the selecting means, and to move the pressing means from the second position to the first position when the usual mode is selected by the selecting means;
• and
• means for rotating the pressing means when the pressing means is located at the second position.