| 摘要 |
PURPOSE:To always attain a proper picture density by providing the second density adjusting means to prevent the variance of adjustment range of the first density adjusting means. CONSTITUTION:At the time when an operator depresses a copy start key 201, a copy density correcting lever 208 is set, and a DC bias value can be changed between about -200V and -450V with a line I2 as the reference in accordance with movement of a copy density lever 207. If the picture density of a finished copy is thinner than the normal value because of the surface state of a photosensitive drum and variance of the voltage of a lamp for original exposure and this density is thinner than a desired density though the copy density lever 207 is set to F9, the copy density correcting lever 208 is moved in the direction of F9 to raise the bias value, and thus pictures of a desired density are attained. If the picture density is thick abnormally, the copy density correcting lever 208 is moved in the direction of F1 oppositely to the above, and pictures of a desired density are attained similarly. |
