| 摘要 |
PURPOSE:To correctly detect the original size even in a condition where a platen cover is not completely closed by confirming that an image element deciding means consecutively decides picture elements in an original region with the prescribed number of times by a size detecting means. CONSTITUTION:The inside of the platen cover is formed with a yellow colored member, the platen cover is illuminated and reflected light from the cover is detected by an image sensor. Data obtained by adding pure yellow density data and black density data from a data outputting circuit for detecting based on the detected data of the image sensor is outputted as the data for detecting size. The detecting data is compared with a threshold value by a comparator, and the picture elements in the original region are decided by the picture element deciding means. The picture element deciding means confirms that the picture elements consecutively exist in original regions of the prescribed number of originals, obtains an original border coordinate and detects the original size. Therefore, even when copying is carried out, if an original is too thick to completely close the platen cover, original size is precisely detected. |
