| 摘要 |
PURPOSE:To attain an automatic exposure quantity adjusting device of a copying machine which is capable of securing an optimum exposure quantity and to improvde an exposure printing performance by comparing and operating a detecting signal of a light transmittance detecting circuit for detecting a light transmittance of an original drawing paper which is carried in, and a detecting signal of a luminous intensity variation detecting circuit for detecting a luminous intensity variation of an exposing lamp. CONSTITUTION:A light source 12 is installed adjacently to an original drawing paper carrying- in driven roller 9. A light transmission quantity detecting sensor 13 is provided opposingly to the light source by placing an original drawing paper carrying path 16 between, detects the light transmission quantity of an original drawing paper A passing through between the sensor and the light source 12, and transmits it to the light transmittance detecting circuit 18. A luminous intensity detecting sensor 14 is provided adjacently to the outside circumferential surface of an exposure printing drum 3, detects a luminous intensity of an exposing lamp 1 transmitting through the exposure printing drum 3, and transmits it to a luminous intensity variation detecting circuit 19. A comparing and operating circuit 21 compares and operates a light transmittance detecting signal of the light transmittance detecting signal, and a luminous intensity variation detecting signal of the luminous intensity variation detecting circuit 19, by which a proper correction is added to the light transmittance detecting signal, also a necessary amplification is given by an amplifying circuit 22, and said signal is transmitted to a peak voltage detecting circuit 23. |
