Patent ID: 8018626

Claim:
An image forming apparatus which copies on a recording sheet an original document carrying a watermark, where a watermark comprising a specific character or a pattern is embedded inconspicuously into an image of the original document, the image forming apparatus comprising: a discrimination section which discriminates a color mode of the original document and a color of the watermark; an image forming section which copies on the recording sheet an image of the original document carrying the watermark with the color mode based on the color mode of the original document and the color of the watermark discriminated by the discrimination section; and a counting section which counts a number of copied sheets as monochrome printing in cases where the discrimination section has discriminated the color mode of the original document as monochrome and has discriminated the color of the watermark as colored, and the image forming section has copied the original document carrying the watermark by the color mode of “color.”