Image formation with gradation value of boundary pixels corrected using cumulative sum of grataion values of pixels in significant image portion

A non-transitory storage medium storing a program causing a computer to execute a control method for an image forming apparatus for forming an image by performing scanning exposure upon a photosensitive member on the basis of a gradation value represented by pixel data, the method comprising:

• sequentially reading, from image data, pieces of pixel data along a predetermined direction;
• calculating a cumulative sum of gradation values represented by pieces of pixel data of target pixels in a significant image portion read in the reading;
• determining whether the target pixel read in the reading is located at a boundary between the significant image portion and a background portion that is a non-significant image portion;
• and
• correcting, in a case where it is determined that the target pixel is located at the boundary in the determining, a gradation value represented by pixel data of the target pixel by adding a correction amount based on the cumulative sum up to the target pixel calculated in the calculating to the gradation value.

A control method for an image forming apparatus for forming an image by performing scanning exposure upon a photosensitive member on the basis of a gradation value represented by pixel data, comprising:

• sequentially reading, from image data, pieces of pixel data along a predetermined direction;
• calculating a cumulative sum of gradation values represented by pieces of pixel data of target pixels in a significant image portion read in the reading;
• determining whether the target pixel read in the reading is located at a boundary between the significant image portion and a background portion that is a non-significant image portion;
• and
• correcting, in a case where it is determined that the target pixel is located at the boundary in the determining, a gradation value represented by pixel data of the target pixel by adding a correction amount based on the cumulative sum up to the target pixel calculated in the calculating to the gradation value.