| 摘要 |
PURPOSE:To obtain a titled device by simple constitution having no sensor by detecting an insertion of an original to a gap between a registration guide and a plate electrode, by a capacity variation. CONSTITUTION:Plate electrodes 17A, 17B opposed to a platen 12 side and a registration 13 side are provided respectively so that air becomes a dielectric. In this state, the size of various originals PA which are placed on the platen 12 and inserted into the gap is detected by a capacity variation between the opposed plate electrodes, based on a size of an area of the part inserted into the gap of these originals PA. This method utilizes a theory by which the larger the size of paper is, the larger the electrostatic capacity becomes, and no matter how many kinds of originals there may be, they can be discriminated. |
