Image forming method and image forming apparatus

Abstract

An image with sufficient gray-scale representation and high resolution is formed on a medium to be recorded, such as an intermediate transfer body, using a thermal printer employing thermal transfer ink. When thermal transfer ink of a thermal transfer ink ribbonis thermally transferred onto an intermediate transfer bodyby a thermal head, gray-scale values of pixels of a filter image having a threshold value pattern used to determine whether each of a plurality of pixels of an original image is an object to be printed, based on gray-scale values of the pixels, are compared with the gray-scale values of the pixels of the original image, and then the gray-scale values of the pixels of the original image are converted based on the result of the comparison. A gray-scale conversion table in which energy applied to the pixels at the time of printing is prescribed corresponding to the gray-scale values of the pixels is compared with the converted gray-scale values of the pixels of the original image, and the converted gray-scale values of the pixels of the original image are further converted on the basis of the result of the comparison. In addition, the application of a current to the thermal headis controlled according to the converted gray-scale values of the pixels of the original image.