Image forming apparatus having an assignment unit that assigns pulse modulation signals in accordance with a predetermined rule and a specific pixel position information

An image forming apparatus for forming a two-dimensional image in which pixels are arranged in a main scanning direction and a sub-scanning direction which is perpendicular to the main scanning direction, comprising:

• n laser elements arranged in the sub-scanning direction and configured to simultaneously scan an image in the main scanning direction by using laser lights emitted from the n laser elements to simultaneously form the image having n lines in the main scanning direction, n being an integer which is 2 or more;
• a pixel selection unit configured to execute a thinning process in which the pixels are thinned to m/n by selecting m pixels among n pixels arranged in the sub-scanning direction, m being an integer which is 1 or more, and the thinning process being executed for the image having the n lines by changing positions of the pixels to be selected according to positions in the main scanning direction;
• a pulse width modulation processing unit configured to sequentially convert image data corresponding to the m pixels selected by the pixel selection unit into m pulse width modulation signals for the m pixels in synchronization with the scan of the image when the image having the n lines is formed;
• a transmission unit configured to transmit the m pulse width modulation signals output by the pulse width modulation processing unit in parallel;
• an assignment unit configured to assign the m pulse width modulation signals transmitted by the transmission unit in parallel to m of the laser elements corresponding to the positions of the m pixels which are conversion sources for obtaining the m pulse width modulation signals;
• and
• a driving unit configured to drive the laser elements to which the pulse width modulation signals are assigned by the assignment unit, in accordance with the assigned pulse width modulation signals.