| 摘要 |
PURPOSE:To improve concn. detecting precision by preventing the effect of the ripple of the light quantity of a copying lamp at the time of detecting toner concn. CONSTITUTION:In the case of the copying lamp which is phasecontrolled and lighted by an AC power source, supply voltage to the copying lamp is as shown by figure (B), and the light quantity of the copying lamp becomes in a state (y) where the ripple exists as shown by figure (C). By setting timing in synchronism with the frequency of the power source, the state of the light quantity of the copying lamp is a gentle state (z) where the ripple does not exist. In the case of detecting the density of a toner image formed corresponding to the light quantity of the copying lamp, by detecting the toner concn in timing like (z), the state the ripple does not exist is obtained also in the detected toner concn. |
