1. Field of the Invention
The present invention relates to gradation-reduction processing technology for reducing the number of gradations for image data.
2. Description of the Related Art
In recent years, as computer output devices, printers that eject ink from nozzles of a printing head are becoming very popular. For example, as disclosed in Unexamined Patent No. 2002-144551, by using quality-enhancing ink for improving the quality of printed matter, there is an attempt to improve quality of printed matter by improving coloring, moisture resistance, and light resistance, and suppressing glossiness. This kind of quality-enhancing ink is almost transparent, so with the gradation-reduction processing that is performed for generating dot data that shows the formation status of transparent dots on each pixel, even more than data precision, it is highly desirable to have shortened time required for the data generating process.
However, in the past, there had not been consideration of constructing a processing method from the perspective of shortening the time required for gradation-reduction processing that is performed with this kind of dot data generating process for transparent dots.