Patent ID: 8670016

Claim:
An exposure device, comprising: an optical system member that causes light irradiated from a light emitting element to converge; an optical system support part that supports the optical system member; and a first fixing member configured to fix the optical system member to the optical system support part, wherein an elongation of the first fixing member is in a range of 40% to 80% inclusive, and a hardness (Shore D) of the first fixing member is in a range of 40 to 90 inclusive, the first fixing member is configured such that a warping of the optical system member is maintained within an allowable range when the exposure device is exposed to a high-temperature environment for an extended period of time, and the first fixing member is configured such that a straightness of the optical system member is maintained within an allowable range even when left under a high-temperature environment for an extended period of time.