IMAGE FORMING APPARATUS AND A COLOR MATERIAL CONTROLLING METHOD

An image forming apparatus comprising: an attachment of a cartridge configured to accommodate a color material; a memory configured to memorize a current cartridge information which shows whether the cartridge attached to the attachment is a first cartridge which accommodates a first color material or a second cartridge which accommodates a second color material; and a controller configured to read the current cartridge information from said memory when the current cartridge attached to the attachment is exchanged to a new cartridge, further said controller configured to judge the new cartridge based on the current cartridge information read from said memory, further said controller configured to temporary stop initiating of a supply of the color material from the new cartridge until the color material supplied from the current cartridge remains in the image forming apparatus when the new cartridge is different from the current cartridge and said controller configured to initiate a supply of the color material from said new cartridge when the color material supplied from said current cartridge does not remain in the image forming apparatus.