Patent ID: 9261807
Filing Date: 2016-02-16
CPC Classification: G03G

Claim Text:
1. An image forming apparatus that is capable of forming an image at a plurality of image forming speeds, the image forming apparatus comprising: an image forming unit that has a first image forming part configured to form a first image in a first color and a second image forming part configured to form a second image in a second color different from the first color, and configured to form an image using the first image forming part and the second image forming part; a housing unit configured to house a recording material; an image bearing member configured to bear the image, and to convey the image; a transfer unit configured to transfer the image borne by the bearing member to the recording material; an obtaining unit that has a sensor which measures a measurement image including a first measurement image and a second measurement image formed by the image forming unit on the image bearing member, and configured to obtain information related to a relative position of the first measurement image and the second measurement image in a conveyance direction of the image bearing member based on a measurement result of the measurement image by the sensor, the first measurement image and the second measurement image being formed by the first image forming part and the second image forming part, respectively; a generation unit configured to generate correlation data based on first information which is a result obtained by the obtaining unit with respect to the measurement image in correspondence with a first image forming speed and on second information which is a result obtained by the obtaining unit with respect to the measurement image in correspondence with a second image forming speed, the correlation data indicating a relationship between a relative position of the first measurement image and the second measurement image in the conveyance direction corresponding to the first image forming speed and a relative position of the first measurement image and the second measurement image in the conveyance direction corresponding to the second image forming speed; a controller configured to, in a case where the image forming unit forms an image at the second image forming speed, correct a relative position of the first image and the second image in the conveyance direction based on the first information obtained in advance by the obtaining unit and on the correlation data generated by the generation unit; and a prohibition unit configured to prohibit formation of the measurement image at the second image forming speed in a case where the housing unit does not house a predetermined recording material corresponding to the second image forming speed.