| 摘要 |
PURPOSE:To provide the original size detection device where detection error can be prevented. CONSTITUTION:The device is constituted so that original detection sensors 407 to 410 are provided in an arm 401 projecting to/evading from the bottom of the original platen glass 101, light receiving quantity of a light receiving element 407b of the original detection sensor against a reference reflection surface 411 is detected at a specified reference time and at a specified time after that, and the light emitting quantity of the light emitting element of the original detection sensor is adjusted so that it is the same light receiving quantity as at the reference time. Furthermore, the arm 401 is projected to the original detection position after being assembled to the device, and initial sensor light quantity adjustment signal inverting output of the light receiving element 407b while gradually reducing the light emitting quantity of the light emitting element 407b from a maximum value, in a no original state, is detected. Initial sensor light adjustment signal inverting output of the light receiving element 407b while gradually increasing the light emitting quantity of the light emitting element from a minimum value in the original existing state is also detected. The device is constituted so that sensor light quantity adjustment signal is defined between both initial sensor light adjustment signals. |
