| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device which prevents an image density variation caused by a large change in developer characteristic due to development conditions, copy duty, etc., and also prevents abnormal images such as base soil, collapse of letters, and sticking of carrier. SOLUTION: The image forming device comprises a developing device (4) which supplies toner to a latent image, formed on an image carrier (1), thereby developing the image, a toner replenishment means (14) which supplies toner to a developing part (4b) of the developing device (4), and a toner concentration detection means (10) which detects the concentration of the toner in the developing device (4). The image forming device also has a toner replenishment control means (16) which controls the toner replenishment based on a result of comparison between an output value sent as a result of the toner concentration detection and a reference value, an image density detection means (7) which forms a reference image on the image carrier (1) in order to use for image density detection and detects the image density of the reference image, and a reference value correction means (17) which corrects the reference value based on an output value of the image density detection means (7). The sensitivity of the toner concentration detection means (10) is set to a specific level, the toner replenishment levels are set in two or more levels using the specific sensitivity, and the specific sensitivity is changed according to the corrected and updated reference value. |
