Patent ID: 8918005

Claim:
A reflection sensor comprising: a light emitting unit that emits light to an area of an image forming apparatus where first detection images of a plurality of colors are formed, the first detection images being used for detecting amounts of misregistration among the first detection images: a first light restricting member/configuration that restricts light emitted from the light emitting unit: a light receiver that is disposed in an optical path of regular reflection light generated as a result of light passing through the first light restricting member/configuration and applied to the area being reflected by the area, and that receives light reflected by the area and outputs a signal representing an amount of received light; and a second light restricting member/configuration that is disposed in the optical path of the regular reflection light and that restricts light to be received by the light receiver, wherein a value obtained by dividing a diameter of the first light restricting member/configuration by a diameter of the second light restricting member/configuration ranges from substantially 0.5 to 1.9, and the diameters of the first and second light restricting members/configurations are each 1.5mm or smaller, and wherein, a distance, in a direction of a normal line with respect to the area, between a position of one of the second light restricting member/configuration, the light emitting unit, and the light receiver at which an amount of light received by the light receiver is maximized and a position of the associated one of the second light restricting member/configuration, the light emitting unit, and the light receiver at which an amount of diffusion reflection light generated as a result of light being reflected by the area is maximized is substantially 1.0 mm or greater.