Image forming apparatus

An image forming apparatus comprising:

• an image forming section configured to transfer a toner image to a recording sheet and to fix the toner image on the recording sheet by heat;
• a filter member configured to trap particles floating in the image forming apparatus;
• a suction section configured to suck air including the particles at a variable suction rate;
• a determiner configured to determine the suction rate of the suction section;
• an exhaust path capable of leading the air sucked by the suction section to outside of the image forming apparatus through the filter member;
• a circulation path capable of allowing the air sucked by the suction section and passing through the filter member to circulate inside the image forming apparatus;
• a switching member configured to make switches between the exhaust path and the circulation path;
• and
• a control unit configured to control at least the suction section and the switching member, wherein
• the control unit allows the switching member to open the exhaust path only when the suction rate determined by the determiner is equal to or less than a predetermined value.