| 摘要 |
PROBLEM TO BE SOLVED: To restrain the load fluctuation of an image carrier by decreasing the pressure of developer in an image forming device equipped with a plurality of contact developing type developing devices and successively switching them to perform development. SOLUTION: In this image forming device, color switching is performed by rotating a developing revolver unit 23 on which four color developing devices 231C, 231M, 231Y and 231K are mounted and successively moving the respective developing devices to a developing position opposed to a photoreceptor 20, and a developing roller 284 has an auxiliary magnetic pole made adjacent to a developing main magnetic pole and assisting it to form magnetic force, so that developing nip width is made small. Therefore, the load fluctuation of the photoreceptor at the time of color switching is restrained to prevent a jitter image from being produced. |
