Image forming apparatus and density correction method in image forming apparatus based on correction characteristics

A density correction method in an electrophotographic image forming apparatus that forms an image by scanning a photoconductor drum in a main scanning direction with light beams based on image data, the density correction method comprising:

• acquiring first correction characteristics representing an output density for an input gradation value at a reference position in a main scanning direction;
• acquiring second correction characteristics representing a relative relationship of an output density at a predetermined position in the main scanning direction with the output density at the reference position in the main scanning direction;
• and
• correcting the image data based on the acquired first correction characteristics and the acquired second correction characteristics.

A non-transitory computer readable storage medium storing a program for causing a computer to function as an electrophotographic image forming apparatus that forms an image by scanning a photoconductor drum in a main scanning direction with light beams based on image data, the program when executed causing the image forming apparatus to:

• acquire first correction characteristics representing an output density for an input gradation value at a reference position in a main scanning direction;
• acquire second correction characteristics representing a relative relationship of an output density at a predetermined position in the main scanning direction with the output density at the reference position in the main scanning direction;
• and
• correct the image data corresponding to the predetermined position in the main scanning direction based on the acquired first correction characteristics and the acquired second correction characteristics.