Patent ID: 8369725

Claim:
An image forming apparatus, comprising: an image forming unit to develop an electrostatic latent image on an image bearing member as a toner image and to transfer the toner image onto a transport member; a first detector including a first light emitting device, a first mixed-light receiving device, and a first diffuse reflection light receiving device, the first mixed-light receiving device detecting a mixed light including regular reflection light and diffuse reflection light, the regular reflection light composed of a regular reflection light component reflected from the transport member when the first light emitting device irradiates the transport member with light, the diffuse reflection light composed of a diffuse reflection light component reflected from the transport member when the first light emitting device irradiates the transport member with light, the first diffuse reflection light receiving device detecting the diffuse reflection light; a second detector including a second light emitting device and a second mixed-light receiving device for detecting the mixed light; and a concentration correction unit to conduct concentration correction using detection results of the first detector and the second detector, wherein the first detector and the second detector are arranged side by side in a main scanning direction of the transport member, the image forming unit develops a first correction pattern using a first color toner that reflects the regular and diffuse reflection light, and transfers the first correction pattern as a concentration correction pattern used for concentration correction by the concentration correction unit at a position on the transport member detectable by the first detector, while the image forming unit develops a second correction pattern using a second color toner that reflects only the regular reflection light, and transfers the second correction pattern as a concentration correction pattern used for concentration correction by the concentration correction unit at a position on the transport member detectable by the second detector.