Code wheel manufacturing method, code wheel, rotary encoder, rotation control unit, belt carrier unit, and image forming apparatus

A manufacturing method for a code wheel for a rotary encoder, the code wheel including, in a central portion, a hole into which a rotary shaft of a rotary member is fitted and a code portion including a radial code pattern in a circumferential edge portion, the method comprising:

• forming the code portion and a reference circle in a plate so that the reference circle has a radius larger than a radius of the hole by a tolerance of deviation between a center position of the code portion and a center position of the hole, and the reference circle has a same center as that of the code portion;
• and
• forming the hole in the plate in which the code portion and the reference circle are formed, so as to be contained in the reference circle,
• wherein the radius of the reference circle is set to be able to tolerate the deviation even when a circumference of the reference circle and a circumference of the hole overlap with each other.