Patent ID: 8811845

Claim:
A registration mark comprising: a set of toner patterns that are formed on a transferred member, which moves along a plurality of toner-image forming units respectively using toners of a plurality of colors and forming a plurality of toner images of different colors, wherein the transfer member receives transfer of the plurality of toner images formed by the plurality of toner-image forming units, wherein the set of toner patterns provides information of toner-image formation positions of the plurality of toner-image forming units to an optical sensor that emits light and receives reflected light, wherein the toners of the plurality of colors comprise a low-reflectance group having a relatively low spectral reflectance and a high-reflectance group having a relatively high spectral reflectance with respect to the light emitted by the optical sensor, wherein the set of toner patterns comprises: a first pattern in which the toner that belongs to the high-reflectance group is distributed without a gap in a moving direction of the transferred member; and second patterns formed with the toner that belongs to the low reflectance group, the second patterns being arranged on both sides of the first pattern in the moving direction of the transferred member without any gap between the first pattern and the second patterns.