An image forming apparatus comprising: a heating unit (93, 94); a fixing member; a power detector (18, 88); a judging unit (11 A, 81a); and a controller (12, 14, 82, 84); characterized in that: a capacitor (17, 87) is configured to be charged by a commercial power (16, 86); the heating unit (93, 94) is configured to be heated by power supplied by the commercial power (16, 86) and the capacitor (17, 87); the fixing member is configured to be heated by the heating unit (93, 94), and to apply heat on an image to be fixed to fix the image on a recording medium; the power detector (18, 88) is configured to detect energy of power stored in the capacitor (17, 87); the judging unit (11A, 81a) is configured to judge whether it is possible to supply power to the heating unit (93, 94) from the capacitor (17, 87) when a plurality of the recording mediums is continuously passed through the fixing member; the controller (12, 14, 82, 84) is configured to perform a reducing control to reduce number of copies of the image formed per minute, when the judging unit (11A, 81a) judges that it is impossible to supply the power to the heating unit (93, 94) from the capacitor (17, 87); and a number of copies prediction section is configured to predict a total number of copies of the image; wherein when the energy of power stored in the capacitor (17, 87) is less than a threshold value for starting electric discharge, the capacitor (17, 87) is charged until the electrical power stored in the capacitor (17, 87) becomes the same as the threshold value; and wherein the threshold value for starting electrical discharge is set based on information of the total number of copies provided from the number of copies prediction section. a heating unit (93, 94); a fixing member; a power detector (18, 88); a judging unit (11 A, 81a); and a controller (12, 14, 82, 84); characterized in that: a capacitor (17, 87) is configured to be charged by a commercial power (16, 86); the heating unit (93, 94) is configured to be heated by power supplied by the commercial power (16, 86) and the capacitor (17, 87); the fixing member is configured to be heated by the heating unit (93, 94), and to apply heat on an image to be fixed to fix the image on a recording medium; the power detector (18, 88) is configured to detect energy of power stored in the capacitor (17, 87); the judging unit (11A, 81a) is configured to judge whether it is possible to supply power to the heating unit (93, 94) from the capacitor (17, 87) when a plurality of the recording mediums is continuously passed through the fixing member; the controller (12, 14, 82, 84) is configured to perform a reducing control to reduce number of copies of the image formed per minute, when the judging unit (11A, 81a) judges that it is impossible to supply the power to the heating unit (93, 94) from the capacitor (17, 87); and a number of copies prediction section is configured to predict a total number of copies of the image; wherein when the energy of power stored in the capacitor (17, 87) is less than a threshold value for starting electric discharge, the capacitor (17, 87) is charged until the electrical power stored in the capacitor (17, 87) becomes the same as the threshold value; and wherein the threshold value for starting electrical discharge is set based on information of the total number of copies provided from the number of copies prediction section. a capacitor (17, 87) is configured to be charged by a commercial power (16, 86); the heating unit (93, 94) is configured to be heated by power supplied by the commercial power (16, 86) and the capacitor (17, 87); the fixing member is configured to be heated by the heating unit (93, 94), and to apply heat on an image to be fixed to fix the image on a recording medium; the power detector (18, 88) is configured to detect energy of power stored in the capacitor (17, 87); the judging unit (11A, 81a) is configured to judge whether it is possible to supply power to the heating unit (93, 94) from the capacitor (17, 87) when a plurality of the recording mediums is continuously passed through the fixing member; the controller (12, 14, 82, 84) is configured to perform a reducing control to reduce number of copies of the image formed per minute, when the judging unit (11A, 81a) judges that it is impossible to supply the power to the heating unit (93, 94) from the capacitor (17, 87); and a number of copies prediction section is configured to predict a total number of copies of the image; wherein when the energy of power stored in the capacitor (17, 87) is less than a threshold value for starting electric discharge, the capacitor (17, 87) is charged until the electrical power stored in the capacitor (17, 87) becomes the same as the threshold value; and wherein the threshold value for starting electrical discharge is set based on information of the total number of copies provided from the number of copies prediction section.