Image forming apparatus that obtains color misregistration amount using detection result of test image

An image forming apparatus, comprising:

• an image forming unit configured to form an image on a rotationally driven image carrier using toner of a plurality of colors including a first color and a second color;
• a detecting unit configured to detect a test image formed on the image carrier by the image forming unit;
• and
• an obtaining unit configured to obtain a color misregistration amount using a detection result of the test image by the detecting unit,
• wherein the test image includes one or more basic patterns;
• each one of the one or more basic patterns includes a first pattern group and a second pattern group disposed at different positions in a conveyance direction of the image carrier;
• the first pattern group and the second pattern group each include a plurality of V-shaped patterns;
• and
• the V-shaped patterns of the first pattern group and the second pattern group have an axisymmetrical shape about an axis corresponding to a width direction orthogonal to the conveyance direction.