Patent ID: 6209987
Filing Date: 2001-04-03
Classification: B41J,G06K

Abstract:
An image formation method of a serial printer comprising:a plurality of print heads placed in a horizontal scanning direction, each head having a plurality of print elements arranged on a carriage in a vertical scanning direction that are driven based on lines of image data read from an image memory, the heads also executing horizontal scanning over a single area a number of times corresponding to a selected number of print divisions so as to form an image,said method comprising the steps of:selecting a print mode from among a plurality of print modes different in print width to form an image by horizontal scanning,reading in advance of printing at least a predetermined number of lines of image data, the predetermined number corresponding to at least the number of lines of image data per print width in the selected print mode divided by the number of print divisions,setting a mode change point in a predetermined line in the read image data if the read image data contains pixels to be printed in a different print mode completing the image to the mode change point if change is made from a selected print mode with a wide print width to a different print mode with a narrow print width by repeating printing a number of times corresponding to the number of print divisions at a same position in the vertical scanning direction while the print width is reduced, andchanging the print mode to the different print mode for continued printing after the mode change point.