An image forming apparatus capable of satisfying various demands of a user by enabling the user to determine a grade of consumables in a single image forming apparatus, and the method of employing the same. The printing method of an image forming apparatus which has a recognition device to print according to grades of consumables, comprises the steps of checking a grade of at least one consumable by the recognition device, searching a setup condition of the apparatus, through which the optimum printing can be obtained by combining the mounted consumables, setting up a printing condition which is preset by the combination of the consumables, and printing with the setup condition by a user's printing command. The image forming apparatus that operates according to grades of consumables, comprises a recognition device capable of recognizing the grades of the consumables, a memory storing image printing information with respect to combinations of the plurality of consumables, and a main control unit the determines the grades of the consumables through the recognition device, and prints the image with the information read from the memory.