Patent ID: 7585040
Filing Date: 2009-09-08
Classification: B41J

Abstract:
1. A printing apparatus which uses a printhead having a plurality of printing elements, and comprises time-divisional driving means for dividing the plurality of printing elements into a plurality of blocks and time-sequentially driving one printing element from each of the plurality of blocks so as to print a halftone image on a printing medium in accordance with a result obtained by performing digital-halftoning for input multi-valued image data in each matrix of a predetermined size, comprising: scanning means for reciprocally scanning the printhead; convey means for conveying the printing medium in a convey direction different from a scanning direction of the printhead; and printing control means for controlling to print a halftone image in each matrix, wherein an arrayed direction of the plurality of printing elements is the convey direction of said convey means, said printing control means controls printing of the halftone image so as to set a size of the blocks to be equal to or an integral multiple of a size of the matrix in the convey direction, and further controls the printing of the halftone image such that a printing position of part of an area printed by the printhead in a preceding scanning by said scanning means coincides with a printing position of part of an area that partly differs from the area printed in the preceding scanning and is printed by the printhead in a current scanning by said scanning means, thereby performing multi-pass printing, and the digital-halftoning increases the number of dots from a center of the matrix as a density expressed by the multi-valued image data increases.