Patent ID: 8564839

Claim:
An electrophotographic image forming apparatus selecting a screen from a plurality of screens corresponding respectively to a plurality of gradation values to form a toner image on media, said plurality of screens each including a pattern in which a first region to which toner is to adhere and a second region to which toner is not to adhere are defined, said image forming apparatus comprising: a storage device; an image forming unit; and a controller, said storage device including a storage area for storing a minimum formable distance between first regions adjacent to each other or second regions adjacent to each other, and said controller performing: a process of calculating a distance between said first regions adjacent to each other or second regions adjacent to each other of said screen; a process, when a distance between said first regions adjacent to each other or second regions adjacent to each other of the screen of said plurality of screens that corresponds to a gradation value of an input image and has a first pattern is smaller than said minimum formable distance, of switching screen pattern to a second pattern different from said first pattern, and selecting from said plurality of screens a screen corresponding to the gradation value of said input image and having said second pattern; and a process of causing said image forming unit to perform image formation using said selected screen.