Patent ID: 7762640
Filing Date: 2010-07-27
Classification: B41J

Abstract:
1. An ink jet printing apparatus which performs printing by ejecting different amounts of ink onto a printing medium so as to form dots of different sizes on the printing medium, said apparatus comprising: a plurality of pixel patterns each representing an arrangement of dots of different sizes forming one pixel, the dots having different dot diameters, each of the pixel patterns indicating a dot arrangement corresponding to data representing a value of levels; image data processing means which quantizes image data into the data representing a value of levels, said image data processing means processing the quantized image data into image data representing the arrangements of dots corresponding to the dots of different sizes in accordance with the pixel pattern corresponding to the value of levels regarding the quantized image data; a printing head having a plurality of ejection ports for forming the dots of different sizes, said printing head provided with an ejection port array in which first ejection ports for forming relatively large dots and second ejection ports for forming relatively small dots are alternatively arranged in a single line in a longitudinal direction of said printing head; scanning means for scanning, in a scan direction, said printing head relative to the printing medium; and printing means which causes said printing head to print the dots of different sizes based on the image data provided by said image data processing means, the data representing an arrangement of dots corresponding to the dots of different sizes,