Patent ID: 11956392
Assignee: RICOH COMPANY, LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  B | IPC B  H

Claim 0:
1. An image forming apparatus comprising:
a conveyer configured to convey a recording medium on which a mark is formed;
an image reader configured to read an image formed on the recording medium while the recording medium is being conveyed;
a detector configured to detect a value corresponding to a conveyance amount of the recording medium conveyed by the conveyer and output the detected value; and
a processor and a memory that stores program instructions causing the processor to calculate a position of the mark on the recording medium with respect to a conveyance direction of the recording medium based on respective detected values output from the detector when an edge of the recording medium and the mark are read by the image reader;
wherein
the image reader is configured to read the image on a per line basis with respect to a line extending along a direction perpendicular to the conveyance direction of the recording medium,
a length of the mark with respect to the conveyance direction is greater than twice a width of each line with respect to the conveyance direction, and
the program instructions further cause the processor to
detect, based on a brightness value of each line read by the image reader, the edge of the recording medium, a front edge of the mark, and a rear edge of the mark, and
calculate a position of the mark on the recording medium with respect to the conveyance direction based on a difference between (i) an intermediate value between a detected value output from the detector corresponding to a front line at which the front edge of the mark is detected and a detected value output from the detector corresponding to a rear line at which the rear edge of the mark is detected, and (ii) a detected value output from the detector corresponding to an edge line at which the edge of the recording medium is detected.