Patent ID: 7304659

Claim:
An image forming apparatus comprising a plurality of optical beam scanning devices for forming scanning lines, utilizing a deflector, or an optical beam scanning device with the deflector utilized commonly by a plurality of scanning light beams, for forming a plurality of scanning lines by light beams from a plurality of light sources, wherein at least one of said plurality of the light sources comprises a semiconductor laser having different number of light emitting points, and the numbers of the light emitting points of the other semiconductor laser arrays are a divisor of a number of the light emitting points with respect to the other semiconductor laser array having the largest number of the light emitting points, wherein a pitch between the light emitting points of the other semiconductor laser arrays having the number of the light emitting points other than the largest number of the light emitting points is a multiple of (number of the largest light emitting points/the number of the light emitting points of the other semiconductor laser arrays) with respect to the pitch between the light emitting points of the semiconductor laser array of the semiconductor laser having the largest number of the light emitting points.