| 摘要 |
PURPOSE:To realize a hue converting circuit to obtain a black character or graphic print on a white paper sheet by ORing exclusively an RGB binary signal inputted in parallel at each picture to decide whether the signal is a black- and-white or a color picture, keeping the same color for the color pattern on a color display device and inverting black/white for the black-and-white pattern. CONSTITUTION:Whether a signal is a black-and-white picture or not is decided by ORing exclusively the inputted RGB signal. An output of an exclusive OR circuit 23 is always logical ''0'' for the black-and-white picture. When information of a picture element with any color is inputted, the said output goes to logical ''1''. When the output of the exclusive OR circuit 23 is logical ''0'', ''0'' is added to a data selecting terminal of data selectors 16-18, and B, G, R data are outputted as they are and in case of a black-and-white pattern, the picture where white and black signals are inverted is printed.
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