Patent ID: 7081913

Claim:
An image forming apparatus, comprising: a data buffer unit configured to buffer input binary data, a sub-scan resolution of which is 2/n (n: an odd integer greater than or equal to 3) times a sub-scan print resolution; a data transform unit configured to transform the input binary data of 2 input scan lines into output multi-level data of n output scan lines of the sub-scan print resolution; and a light beam modulation unit configured to modulate radiant energy of a light beam in accordance with the output multi-level data, wherein the data transform unit sets the output multi-level data of upper (n−1)/2 output scan lines equal to the input binary data of an upper input scan line, the output multi-level data of lower (n−1)/2 output scan lines equal to the input binary data of a lower input scan line, and the output multi-level data of a middle output scan line based on the input binary data of the upper input scan line and the input binary data of the lower input scan line.