To provide an inner drum exposure apparatus that makes a high-speed exposure process possible by changing resolution, while keeping an originally set separation width of light beams in the sub-scanning direction.
Laser beams La, Lb emitted as modified based on an image signal in the optical system of a light source side are polarized and multiplexed by a polarization beam splitter 38 and are exited as laser beams La, Lb to a right-handed circularly polarized light and a left-handed circularly polarized light. These exited laser beams are converted into linearly polarized light beams, orthogonal to each other by a quarter-wave plate 26 disposed on the optical path of a scanning means 16, and passed through a uniaxial crystal optical element 28 to produce separated multi-beams which carry out exposure processings. The separation width of beam spots on the scanning surface, determined by the uniaxial crystal optical element 28, is controlled to form an appropriate image, in such a manner that even if the resolution of the inner drum exposure apparatus is changed, scanning uneveness of image formed on the scanning surface will fall within the allowable range.
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda