Patent ID: 7885560

Claim:
An image-forming device comprising: a moving member having a surface movable; a patch mark-forming unit configured to form a first patch mark at a first density on the surface; a light emitting unit that emits an incident light onto the surface moving, at an incident angle for the surface, the incident light reflected by the surface being divided into a mirror-reflected light and a diffusion-reflected light on the surface, the mirror-reflected light being reflected by the surface at a reflected angle equal to the incident angle; a first detecting unit configured to detect an amount of the diffusion-reflected light; a density controlling unit configured to control the patch mark forming unit to reform a second patch mark at a second density weaker than the first density if the amount detected by the first detecting unit is larger than a threshold; a second detecting unit configured to detect an amount of the mirror-reflected light reflected by the surface on which the second patch mark has been reformed; a position calculating unit configured to calculate, based on the amount detected by the second detecting unit, a position on the surface at which an image should be formed; and an image-forming unit configured to form an image at the position.