Patent ID: 9256181
Filing Date: 2016-02-09
CPC Classification: G03G

Claim Text:
1. A belt unit comprising: an endless belt supported in such a manner that a surface thereof bearing a toner image can perform a circulating motion along a predetermined moving direction; a reading section that is disposed below the endless belt in a vertical direction and reads the toner image from the surface of the endless belt; a supplementary roller is configured so as to be movable between a contacting position at which the supplementary roller is in contact with a rear face of the endless belt in such a manner that a gap between a reading face of the reading section and the surface of the endless belt is kept constant and a separate position at which the supplementary roller is away from the rear face of the endless belt, the supplementary roller being located on a downstream side of the reading section in a horizontal direction by a predetermined distance; and a moving mechanism that causes the supplementary roller to be located at the contacting position only when reading is carried out by the reading section, wherein the predetermined distance is a distance from a center of the reading face to a point of contact at which the supplementary roller is in contact with the endless belt in the horizontal direction, wherein the predetermined distance is the same in length as a radial distance of the supplementary roller.