| 摘要 |
PURPOSE:To form an image with invariably optimum density by setting image formation condition which determines image density according to the detection result of an environment detecting means and the kind of a developer. CONSTITUTION:The environment sensor 19 consisting of a humidity sensor and a temperature sensor is arranged at the position where the moisture absorption of toner is well reflected, e.g. nearby a toner hopper or developing device, and a control means 18 is connected to the environment sensor 19 and a potential sensor 20. The density decreases under one and the same condition as humidity is low and increases as the humidity increases. For the purpose, a contrast potential Vcont is found by detecting the humidity and the image formation condition is set according to the value, thereby obtaining a stable image regardless of variation in environmental condition. Further, the image formation condition is set at every color and then even a difference in image density due to a difference among the colors of developer is corrected. |
