Patent ID: 9104173
Filing Date: 2015-08-11
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: an image formation unit configured to form an image on a sheet; a sensor unit having a light-emitting device and a light-receiving device; a frame to which the sensor unit is attached; at least one projection provided on one of the sensor unit and the frame, the at least one projection being formed to have a contacting part which projects to contact the other of the sensor unit and the frame; at least one engagement part provided on one of the sensor unit and the frame, the at least one engagement part being formed to engage with at least one catching part provided on the other of the sensor unit and the frame and to press the at least one projection in a direction of increasing a contact surface pressure of the contacting part by causing elastic deformation; and a projecting part provided on one of the sensor unit and the frame, the projecting part being formed to fit into a recessed part formed in the other of the sensor unit and the frame; wherein: the at least one engagement part comprises a first engagement part and a second engagement part; each of the first engagement part and the second engagement part comprises a first extending part formed to extend in a direction parallel with a projecting direction of the at least one projection, and a second extending part formed to extend in a direction perpendicular to an extending direction of the first extending part from a tip of the first extending part in the extending direction of the first extending part, so that each of the first engagement part and the second engagement part is formed in shape of a letter L; the second extending part of the first engagement part and the second extending part of the second engagement part extend in a same direction; the at least one catching part comprises a first through hole through which the first extending part of the first engagement part penetrates and a second through hole thorough which the first extending part of the second engagement part penetrates; the second extending parts of the first engagement part and the second engagement part engage with portions around the first through hole and the second through hole, respectively; the first extending parts of the first engagement part and the second engagement part contact outer edges of the first through hole and the second through hole, respectively, so that movement of the first extending parts of the first engagement part and the second engagement part in a direction perpendicular to the extending direction of the first extending part and an extending direction of the second extending part is restricted; and the projecting part is formed to contact an inner edge of the recessed part so that movement of the projecting part in the extending direction of the second extending part is restricted.