Patent ID: 7792441

Claim:
An image formation apparatus, comprising: a plurality of image formation units to form toner images in different colors on corresponding image supporting objects; a middle transfer object, to which the toner images in different colors formed on the image supporting objects of the image formation units are transferred one by one; an image detection unit that includes a luminous source for irradiating a light to a position where the toner image passes, and an optical receiving unit to receive the light that is reflected by the toner image; and a control unit to control image formation conditions based on a detection result of the image detection unit, wherein the image detection unit includes an image supporting object image detection unit that is arranged countering each of the image supporting objects of the image formation units, and a middle transfer object image detection unit that is arranged countering the middle transfer object; the image formation unit includes a transfer effectiveness detection unit to detect transfer effectiveness between the image supporting object and the middle transfer object by detecting a difference between a toner adhesion amount of a toner image of a color detected by the image supporting object image detection unit and a toner adhesion amount of the toner image in a same color detected by the middle transfer object image detection unit for all the colors; and the image formation apparatus further comprises an image detection switching unit that selects the image supporting object image detection unit when controlling image formation conditions, and selects the middle transfer object image detection unit during printing.