Image forming apparatus, exposure apparatus, image holder, image forming method, and exposing method

An image forming apparatus comprising:

• an image holder;
• an exposure member that has an exposure portion exposing the image holder;
• a first positioning unit that determines a distance in a first direction, which is a direction of an optical axis of the exposure member, between the exposure member and the image holder;
• and
• a second positioning unit that determines a position of the exposure member with respect to the image holder in a second direction being a direction of an axis line of the image holder, and a position of the exposure member with respect to the image holder in a third direction, the third direction being perpendicular to both the first direction and the second direction, wherein the first positioning unit is disposed closer to the exposure member than the second positioning unit at a same side of the exposure member,
• wherein the first positioning unit is disposed closer with respect to the second direction to the exposure member than the second positioning unit as a same side of the exposure member with respect to the second direction.