| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device applying proper quantities of charge and toner for development, with excellent developer flowability, reducing the scattering of the toner and a load applied to the developer so as to suppress a deterioration in the developer and executing a high-image-quality developing operation for 30 to 200 printing service hours, regardless of a compact device. SOLUTION: The image forming device uses magnetic carriers having 50 to 130μm average grain size and the toner having 6 to 10μm average grain size and is provided with the developer obtained by mixing the toner with the magnetic carriers at a covering rate of 0.3 to 1.0, a developing roll whose diameter is 10 to 30mm, a means for stirring/mixing the developer with fresh toner supplied to the developer, a developing device 4 having a developer storage capacity of 0.2 to 0.8kg and a photoreceptor 1 rotated at a circumferential speed ratio of 0.7 to 4 with respect to the developing roll. Each value of the developer, the developing device 4 and the photoreceptor 1 is set to obtain conditions satisfying a process speed of 80 to 300mm/s and 30 to 200 printing service hours of the developing device 4, to form an image. |
