A method and apparatus for image forming capable of effectively avoiding an adverse temperature effect to an optical scanning system

摘要

An image forming apparatus includes a support member, an image carrying member, and an optical writing apparatus. The image carrying member carries a toner image on its surface. The optical writing apparatus is connected to the support member, and writes an electrostatic latent image on the image carrying member. The optical writing apparatus includes an optical system, a first casing, and a second casing. The optical system has at least one optical element. The first casing supports the optical system. The second casing encases the first casing and prevents intrusion of dust to the optical system. The first casing is made from a material having a line expansion coefficient smaller than the second casing.