| 摘要 |
PROBLEM TO BE SOLVED: To form a stable toner coat and to acquire a high grade image by stopping a rotary supporting device, so as to arrange a magnetic toner developing unit, in the highest position of the ambient temp. of the rotary supporting device, for a stand-by period. SOLUTION: A developing device 4 consists of developing units 4a-4d for yellow, magenta, cyan and black and is rotated in the direction of an arrow K, to move to a position facing a photoreceptive drum, by the rotary supporting device 6, to attain development, at the time of forming respective color images. When the color toner developing units 4a-4c including nonmagnetic toner become stand-by states at the position of the black developing unit 4d, an atmosphere exceeds 50 deg.C and a deterioration in toner is quickened. When a stand-by time is long, the deterioration in the toner is conspicuous. Therefore, during the standby time, the black developing unit 4d including the nonmagnetic toner is arranged in the position nearest to a thermal fixing device 13, where the direct conduction of heat from the thermal fixing device 13 is easy. Therefore, damage to the nonmagnetic toner is prevented and the deterioration in the toner is suppressed. |
