| 摘要 |
PROBLEM TO BE SOLVED: To eliminate unpleasantness such as glare in detecting the size of a paper sheet and to shorten time needed for the detection, in an image forming device capable of detecting the size of the paper by making use of an image recording means. SOLUTION: A signal is transmitted to a control circuit 45 of an image reading part 1 from a control part 27, in detecting the size of a paper, and a voltage output from a lamp regulator 46 on the control circuit 45 is changed to make the quantity of light emitted from an exposing lamp 9 smaller than that in reading an original. The emitted light quantity in reading the original is so large that an operator feels rather glaring, when a platen cover is opened. However, for detecting the size of the paper, the emitted light quantity is enough, when the presence of the reflection of the light can be detected, so that even if the platen cover is opened, and there is no light reflection by the platen cover, that is, the reflected light comes only from the paper, the emitted light quantity can be fairly reduced. |
