The big problem with colour printing is that the paper has to make four passes over the transfer mechanism to take the three subtractive colours and black, which means four times the opportunity for jams, four times the danger of the thing coming out off register. But Colorocs Inc, of Norcross, Georgia may have an answer. Last week at the Siggraph show in Atlanta, the company was showing off a $30,000 colour printer that needs just one pass of the paper. Instead of the paper, the printer passes an imahe storage belt four times through the Sharp Corp print engine, and only then does the belt apply the entire colour image to the paper, and fuse it. The resolution is 300 by 300 dots per inch and the speed is about six A4 pages a minute – it can do single colour pages at 45 pages a minute. The printer will be available on the OEM market by year-end.