Abstract: A multi-gradation image having a plurality of colors is binary coded by processing halftones in a pseudo manner. After the binary coding, an undesirable overlaying of colors on the image is eliminated so that image quality can be improved and also process load can be alleviated. A detailed process is this: Colors at a target pixel are binary coded, and the results are retained as data. When a color following the color already binary coded is processed, the retained data of the preceding color is referred to, thereby avoiding an undesirable composite black due to an overlaying of three primary colors on the same pixel. When the colors of an input image include black (K), this K is firstly binary coded at the target pixel, and when K is output, the other colors are halted outputting or a threshold value is set so that the other colors are not output. When K is not output, the other colors are binary coded in the order of higher density or higher visual sensitivity so that a quality image can be output.

Abstract: In a head drive unit of ink-jet recorder and the like, for the purpose of reducing amount of data for head driving waveform and data processing time, a time data at a point where an electric current changes and an electric current data are stored in time data storage means and electric current data storage means, and the time data is compared with a count data of an address counter. The electric current data is then output to drive a head, when the data matches as a result of the comparison.

Abstract: In a head drive unit of ink-jet recorder and the like, for the purpose of reducing amount of data for head driving waveform and data processing time, a time data at a point where an electric current changes and an electric current data are stored in time data storage means and electric current data storage means, and the time data is compared with a count data of an address counter. The electric current data is then output to drive a head, when the data matches as a result of the comparison.