Registration mark and image forming apparatus

In a registration mark, when toners of plural colors are divided into two groups of a low-reflectance group having a relatively low spectral reflectance and a high-reflectance group having a relatively high spectral reflectance in accordance with high and low levels of spectral reflectances with respect to light emitted by an optical sensor, a toner pattern that gives information of a toner-image formation position of a toner-image forming unit using the toner that belongs to the low-reflectance group includes 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 used by the toner-image forming unit, the second patterns being arranged on both sides of the first pattern in the moving direction of the transferred member without a gap with respect to the first pattern.