Patent ID: 7385730

Claim:
An image processing apparatus that performs image processing to print an image on a print medium using a print head capable of printing dots of a plurality of types of print materials, including deep-color print materials and light-color print materials, said apparatus comprising: storage means for storing dot patterns, including a first set of dot patterns corresponding to a first deep-color print material, a second set of dot patterns corresponding to a second deep-color print material, a third set of dot patterns corresponding to a first light-color print material, and a fourth set of dot patterns corresponding to a second light-color print material, wherein each dot pattern corresponding to the first and second deep-color print material is associated with one of a first number of gradation levels, and a position of a pixel of the image, and each dot pattern corresponding to the first and second light-color print materials is associated with one of a second number of gradation levels greater than the first number and the position of the pixel; and selecting means for selecting a dot pattern from the dot patterns stored in said storage means, based on a corresponding gradation level and position of the pixel, wherein the first light-color print material has a same color as the first deep-color print material and has lower density than that of the first deep-color print material, and the second light-color print material has a same color as the second deep-color print material and has a lower density than that of the second deep-color print material, wherein the dot pattern corresponding to the first deep-color print material is different from the dot pattern corresponding to the second deep-color print material at the same gradation level and the same pixel position, and the dot pattern corresponding to the first light-color print material is different from the dot pattern corresponding to the second light-color print material at the same gradation level and the same pixel position, and wherein a print resolution of the dot patterns corresponding to the first and second deep-color print materials is lower than a print resolution of the dot patterns corresponding to the first and second light-color print materials.