CORRECTING DEVICE FOR PAPER SHEET TIP PORTION

PURPOSE:To always and automatically make a paper sheet coincide with the position of a picture image by providing a measuring means for time from the issuing of a timing signal basic for a timing on signal until the attainment of the tip of the paper sheet to a detecting sensor arranged after a timing roller for the tip of the paper sheet. CONSTITUTION:Exposure is begun through a laser beam 2 after (t) hours from the time when the primary paper sensor 5 has detected the tip of a paper sheet fed from paper feed rollers 4a-4c. A timing roller 6 is set to be turned on after T hours from the beginning of the exposure, and the above-mentioned T hours can be automatically corrected. Namely, after the paper sheet is fed through the timing roller 6, time required for the tip of the paper sheet to attain the position of the secondary paper sensor 7 is measured, and then is converted into the time from the beginning of the exposure to the turning on of the timing roller on the basis of the above-mentioned measured result, and moreover, corrected.