Patent ID: 8120635

Claim:
An image forming apparatus, comprising: a photosensitive drum; and an exposure head that exposes the photosensitive drum and includes a lens array and a head substrate, the lens array having a light transmissive substrate whose length in a first direction is greater than a length thereof in a second direction orthogonal to the first direction, a first lens that is arranged on the light transmissive substrate, a second lens that is arranged on the light transmissive substrate at the first direction of the first lens, and a third lens that is arranged on the light transmissive substrate at the second direction of the first lens, the first lens and the second lens being connected in the first direction, the first lens and the third lens being not connected, the head substrate being provided with two light emitting elements that emit a light to be imaged on the photosensitive drum by the first lens, two light emitting elements that emit a light to be imaged on the photosensitive drum by the second lens, and two light emitting elements that emit a light to be imaged on the photosensitive drum by the third lens, wherein a boundary between the first lens and the second lens is at a height Δ from the light transmissive substrate, and shapes of the first lens and the third lens are different from each other so that a position at which a light is imaged by the first lens and a position at which a light is imaged by the third lens are positions in conformity with a shape of the photosensitive drum.