Patent ID: 8584371

Claim:
A paper size detecting mechanism, comprising: a restricting member which is reciprocably provided on an inside of a bottom of a paper feed cassette unloadably loaded in a cabinet of an image forming apparatus and which restricts an edge of paper accommodated in the paper feed cassette; a following member including a following arm portion of which one end is coupled to the restricting member and an arc-shaped portion which is continuous with another end of the following arm portion and which has formed thereon at least one protrusion protruding in a radial direction, the following member being provided swingable in concert with movement of the restricting member; a detecting member which is arranged in the cabinet of the image forming apparatus at a position facing the arc-shaped portion and which has a plurality of detecting plates elastically deformable by contact with the protrusion, the detecting plates each including a base-end portion of which one end is supported on a main portion of the detecting member and a swing portion which is located on a tip-end side of the base-end portion and with which the protrusion makes contact, the base-end portion in at least one of the detecting plates having a wider elastically deformable range than the swing portion; a multiple switch which is provided on a rear side of the detecting member and which has a plurality of contacts switchable between an on state and an off state by elastic deformation of the plurality of detecting plates; and a prop which is provided horizontally over the multiple switch and which is kept in contact with a reverse side of the detecting plates, at the base-end portion thereof, to serve as a fulcrum of swinging, the paper size detecting mechanism detecting size of the paper accommodated in the paper feed cassette.