Patent ID: 7950657

Claim:
A printing apparatus, comprising: a printing mechanism forming an image on a sheet transferred in a sheet transfer route; a sheet feeding mechanism feeding sheets to the sheet transfer route; a register provided between the sheet feeding mechanism and the printing mechanism on the sheet transfer route so as to position a sheet fed from the sheet feeding mechanism and adjust an obliqueness of the sheet; an edge part detector provided on the sheet transfer route having a detecting section configured between the register and the printing mechanism so as to detect edge parts of a sheet transferred to the printing mechanism by the register, wherein the edge part detector is configured to serve as a multi-feed detector to detect multi-feeding of sheets, wherein the edge part detector includes a light transmission sensor provided with a light emitter and a light-receiving sensor, and detects multi-feeding of sheets by sampling output signals from the light-receiving sensor in a plurality of sampling points in detection blocks preliminarily set on a sheet.