The 1st heat quantity calculation means which calculate

摘要

PROBLEM TO BE SOLVED: To predict temperature in a charging means and control the charging means according to the predicted temperature.;SOLUTION: A control part 80 calculates heat quantity flowed into a thermometer 15. Using the calculated heat quantity and a value determined according to each positional relationship between an electrifier 32 of each image forming unit 13 and the thermometer 15, heat quantity flowed into the electrifiers 32 is calculated. Then, the control part 80 divides this calculated heat quantity by heat capacity of the electrifier 32 to calculate temperature change of each electrifier 32. The calculated temperature change of each electrifier 32 is integrated, so that temperature of each electrifier 32 is predicted. Then, CPU 81 determines a value of current used when the electrifier 32 charges a photoreceptor drum 31 according to the predicted temperature of the electrifier 32.;COPYRIGHT: (C)2011,JPO&INPIT