Image processing apparatus, method of processing images, and printing apparatus to which image processing method is applied

Abstract

A printing apparatus of the present invention prints an image corresponding to image data, which are divided into a plurality of pages and supplied from an application program, on a roll of machine glazed paper without any margin set between the adjoining pages. This arrangement enables printing on a large-sized printing medium, such as a banner. A printer driver incorporated in the printing apparatus causes the image data divided into the plurality of pages to be subjected to halftone processing according to an error diffusion method. When a standard printing mode is specified, an error buffer is initialized on every instruction of a new page. When a continuous printing mode is specified, on the other hand, the error buffer is not initialized. This causes an error occurring in a certain pixel included in one page to be diffused to pixels included in a next page in the continuous printing mode. The arrangement of the present invention enables the image data divided into a plurality of pages to be collectively processed by the halftone processing and thereby improves the picture quality of the image especially in the vicinity of a boundary between the adjoining pages.