| 摘要 |
PURPOSE:To eliminate both the shadow of the front end of an original and the shadow of a stuck original from an image completely by cutting off auxiliary illumination and using only main illumination when a white part is exposed, and increasing the lamp input of a main lighting means at this time by a deficiency in the quantity of light obtained when an auxiliary lighting means is not cut off. CONSTITUTION:For example, the ratio of the quantity of light between the main illuminating means 17 and auxiliary illuminating means 19 is 7:3 and when auxiliary illumination is cut off and only main illumination is used in this state, the quantity of light is 70% of the proper quantity of light. In other words, there is a 30% deficiency in the quantity of light so that the potential to which a photosensitive drum is charged electrostatically drops to a white proper potential, and the whole becoes deficient in the quantity of light in this state to cause fogging. For the purpose, the input voltage to an exposure lamp 20 is raised to increase its quantity of light. For example, when the exposure lamp having a rating of 80V is used with a 65V input, the quantity of light is increased by about 30% by increasing the lamp input from 65V to 70V. |
