Patent ID: 6943918
Filing Date: 2005-09-13
Classification: H04N

Abstract:
1. A printer-system that creates a plurality of dots and thereby prints an image on a printing medium, said printer-system comprising: a head configured to produce N different dots having different densities per unit area, where N is an integer of not less than 2; an input unit configured to input tone data with respect to each of the pixels included in an original image; a threshold value storage unit configured to store a plurality of threshold values according to possible tone values that the input tone data may take, the threshold values including respective threshold values that correspond to P different dots, where P is an integer satisfying 2≦P≦N; a multi-valuing unit configured to determine an on-off state of a dot and which of the N different dots is to be created in each pixel based on density data obtained by an error diffusion distribution of an error, said error representing a difference between a density to be expressed in a processed pixel and a density expressed by a dot actually created in the pixel; and a dot creation unit configured to drive said head and create the N different dots having different densities per unit area based on results of the determination.