Abstract: A device of this invention has a hollow heat roller (1), the surface of which has a coat of a metal layer, an excitation coil which is arranged in the heat roller (1) and generates a magnetic flux in the heat roller (1) to heat it by induction, and a press roller (2) which is in contact with the heat roller (1) under a predetermined pressure. The excitation coil has at least two maximal heating portions (42, 43) in the circumferential direction of the heat roller (1). The excitation coil is located to form one maximal heating portion (42) within the range of ±30° along the circumferential direction from the position of a nip (41) where the heat roller (1) contacts the press roller (2). With this structure, since heat accumulates in the heat roller (1) to keep it warm, the warm-up time can be shortened.

Abstract: A fixing device in an image forming apparatus having various functions such as print data reception, FAX transmission/reception, and the like, has a member to be heated (1), an excitation coil (2) which is arranged in the vicinity of the member to be heated (1), and heats the member to be heated (1) by induction upon receiving a current, an induction heating control circuit (7) for controlling current supply to the excitation control (2), and a main body control circuit (14) for controlling the operation of the image forming apparatus main body. The induction heating control circuit (7) has a central processing unit (9) independently of the main body control circuit (14). The main body control circuit 14 can control the excitation control 92) by supplying a heating ON/OFF signal to the central processing unit without directly controlling current supply to the excitation coil (2).

Abstract: An image forming apparatus of the present invention includes a main body, a fixing device arranged in the main body and supported so that it can be pulled out of the main by for fixing an image formed on one side of a paper, a duplex device arranged in the main body and supported so that it can be pulled out of the main body for once housing a paper having an image fixed on one side and taking it out with the other side having no image fixed facing toward the fixing device; and a coupling unit for coupling so that the fixing device and the duplex device can be pulled out of the main body simultaneously.