Patent ID: 7834898

Claim:
An image forming device comprising: a photoconductor drum having a rotational shaft in a first direction; and an exposure head having a plurality of imaging optical systems disposed in the first direction and a second direction and each having a negative optical magnification, and a light emitting element substrate on which a plurality of light emitting elements are disposed, the plurality of light emitting elements emitting light beams imaged on the photoconductor drum by one of the imaging optical systems; a drive section that drives the photoconductor drum; and a gear having a pitch G, and for transmitting driving force from the drive section to the photoconductor drum, wherein the light beams are imaged by the imaging optical systems disposed in the second direction on the photoconductive drum at positions different from each other in the second direction, the imaging optical systems are disposed linearly in the first direction to form a plurality of imaging optical system lines, and the pitch G has a following relationship with a width Da between the plurality of imaging optical system lines: Da>(½)×G.