To provide an image forming apparatus and an image reading apparatus which can discriminatingly detect the skew and the corner-folded portion of a conveyed paper sheet.
An image forming apparatus includes a plurality of light transmitting members which are linearly arrayed in a first direction perpendicular to a convey direction on a convey path of a paper sheet, is changed from a first posture to a second posture when the tip of the paper sheet abuts against them and return from the second posture to the first posture when the trailing end of the paper sheet is separated from them, and have different light transmissivity, a light irradiation means which is arranged on one side of each light transmitting member, transmits light when the plurality of light transmitting members are in the first postures, and irradiates inspecting light by a passing optical axis when the light transmitting members are in the second postures, a light receiving element which are arranged on the other side of each light transmitting member, and outputs a light receiving signal of a voltage corresponding to the amount of light obtained by transmitting and/or making the inspecting light pass through the light transmitting members, and a control portion which determines the convey state of the paper sheet based on the change of a voltage of the light receiving signal.
| JPH04189239 | OFFSET AND SKEW CORRECTING SYSTEM IN PRINTER DEVICE |
| JPH08337340 | POSTAL MATTER TRANSPORT DEVICE |
TAKIGUCHI FUMIAKI
Takashi Watanabe
Yasuhiko Murayama