Fixing device and image forming apparatus

An image forming apparatus comprising:

• a fixing device for fixing a toner image onto a recording paper sheet, wherein
• said fixing device includes:
• a heating member for heating said recording paper sheet;
• a pressing member for applying a pressure by forming contact with said heating member;
• a casing accommodating said heating member and said pressing member, and provided with an exit port for discharging said recording paper sheet;
• a closing portion arranged at said exit port for keeping a temperature of said casing, said closing portion having a rotation member and an opposed member forming a nip region together with said rotation member;
• and
• a separating unit for changing at least a part of said closing portion from a closed state to an open state.

A fixing device for fixing a toner image onto a recording paper sheet, comprising:

• a heating member for heating said recording paper sheet;
• a pressing member for applying a pressure by forming contact with said heating member;
• a casing accommodating said heating member and said pressing member, and provided with an exit port for discharging said recording paper sheet;
• and
• a closing portion arranged at said exit port for keeping a temperature of said casing, wherein
• said closing portion has:
• a rotation member for discharging said recording paper sheet, and
• an opposed member forming a nip region together with said rotation member,
• said opposed member has first, second and third regions in a circumferential surface direction,
• said first region has an arc-shaped form, and forms a nip region along an entire length in a lengthwise direction of said rotation member,
• said second region is provided with a partial arc-shape portion for forming a nip region along a partial length in the lengthwise direction of said rotation member, having a first retracted portion for avoiding contact with said rotation member other than said partial arc-shape portion, and
• said third region is provided with a second retracted portion avoiding contact with said rotation member along an entire length in a lengthwise direction of said rotation member.