The images are etched onto copper sheets instead of aluminium like offset litho and then wrapped around a cylinder. It works upside down in comparison to offset litho, with the impression cylinder on the top instead of the bottom. There is also one less cylinder involved, cutting out the 'blanket' cylinder all together. Because this cylinder is missing, the image etched onto the copper plate is a mirror image to ensure that it prints the right way up on the paper/plastic/fabric.
The vast majority of rotogravure printers are web fed, and the few sheet fed ones that exist are classed as a 'speciality market'. One example of roto printing would be newspapers. Rotogravure presses are the fastest printing process and can print onto very wide substraits, such as vinyl flooring.
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