IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus which is capable of suppressing the occurrence of an image defect, even when a sudden change occurs in the external environment.SOLUTION: The image forming apparatus includes a first environmental sensor 111 detecting at least one of the temperature and humidity of the inside of the image forming apparatus and a second environmental sensor 112 detecting at least one of the temperature and humidity of the outside of the apparatus. The image forming apparatus is configured so as to include a driving circuit 103 for decreasing the air quantity of a blower fan 92 for sending external air to an electrifier electrifying an image carrier than a previously set threshold or stopping the blower fan 92, when the temperature or humidity detected by the second environmental sensor 112 is higher than the temperature or humidity detected by the first environmental sensor 111 and at least one of the differences between the temperature or humidity detected by the second environmental sensor 112 and the temperature or humidity detected by the first environmental sensor 111 is a first threshold or more.