Patent ID: 8319811

Claim:
An image forming apparatus comprising: a photoconductive member; a charger configured to charge a surface of the photoconductive member; a laser light source configured to emit at least two laser beams at once; an optical scanning system configured to simultaneously form a group of at least two scanning lines extending in a main scanning direction on the surface of the photoconductive member, each of said at least two scanning lines being formed at a prescribed scan line interval in a sub scanning direction; a scan controller configured to control the laser light source to repeatedly emit the at least two laser beams at different times; and an exposure intensity distribution changing device configured to symmetrically change exposure intensity distribution of each of the at least two scanning lines in the main scan direction, wherein a group of at least two scanning lines formed next on the photoconductive member partially overlaps with a group previously formed with displacement of a prescribed feed pitch in the sub scanning direction, so that prescribed numbers of the at least two scanning lines of the different groups neighboring to each other are paired to form a prescribed number of combination scan lines, said combination scan lines constituting a latent image formed on the photoconductive member, wherein said exposure intensity distribution changing device substantially equalizes a sum of the exposure intensity of the pair of neighboring scan lines of the combination scan line at every section in the main scanning direction, and wherein said scan line interval is one of D+δ or D−δ at a center and D at the remaining sections of each of the at least two scanning lines and said prescribed feed pitch is ND when 2N represents a number of the scanning lines formed at once and the following inequality is met; 0≦ δ≦D.