Photos: Art of the printer cartridge refill

The printer supply business is lucrative: it's estimated that companies that produce hardware, paper, ink, and cartridges make $70 billion in sales each year. Now, what was once a niche segment of the market--printer cartridge refilling--is rapidly becoming an indispensible part of the industry. As businesses and consumers find out about the less expensive and often more environmentally friendly option of getting cartridges refilled by third-party companies instead of going to the printer manufacturer, refillers are gaining ground. Currently they do about $15 billion in business annually.

So how does it all work? One of the biggest cartridge refillers, Cartridge World, based in Emeryville, Calif., invited CNET News.com for an inside look.

When an empty cartridge is brought in, the first step is making sure the cartridges are in working condition and even able to be refilled. A visual inspection and an electronic test to make sure the contacts on the cartridge are still functioning is step No. 1. Pictured here are used inkjet cartridges from Hewlett-Packard and Lexmark. By the time the process is complete there will be no trace of either manufacturer's brand on the final product.

Caption text by News.com reporter Erica Ogg.