| 摘要 |
PROBLEM TO BE SOLVED: To make an image forming device possible to attain such as reduction in running cost, by minimizing a consumption of toner by saving excessive toner sticking to the latent image on a photoreceptor, in addition to satisfying the image quality required by a user. SOLUTION: With this image forming device, since reflection density of the output image is saturated at a point that the development contrast is high, the image density is observed as the same to a user, regardless of the toner quantity on the image beyond that, as a result the toner wasted uselessly. Patches are formed on a photosensitive drum with the density from A0H to FFH, measured by a sensor. Then, density gradient between patches is taken, and inclination of the gradient (second differential of density) is taken in addition thereto, and moreover inclination between the patch potential and DC component of developing bias becomes to 0 for the second time is defined as the optimum development contrast. At this time, since the development DC component is unchanging, the development contrast is controlled by the potential on the maximum image part at the time of forming the latent image on the photosensitive drum (maximum light quantity of laser). Since the second differential value becomes 0 at E0H, the E0H is regarded as the maximum light quantity. |
