| 摘要 |
PROBLEM TO BE SOLVED: To prevent fluctuation in toner concentration by deciding whether or not developer in a developing device is stirred based on a difference between a toner concentration control reference value and an output value from a toner concentration detection means and an output value from an image density detection means. SOLUTION: After a drum-like photoreceptor 1 is driven to be rotated in a direction shown by an arrow by a rotating and driving part and uniformly electrified by an electrifier 2, an image is written by the radiation of exposing light 3 from an exposure device so as to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 1 is developed with two-component type developer including toner and carrier by the developing device 4 and becomes a toner image. In such a case, the device is provided with a toner replenishing roller control means 16 functioning as a developer stirring control means for deciding whether or not the developer in the device 4 is stirred based on the difference between the toner concentration control reference value and the output value from the toner concentration detection means (T sensor) 14 and the output value from the image density detection means (P sensor) 8. Thus, the toner concentration is stabilized and surface staining is eliminated. |
