The first in a series of occasional contributions from Simon Hurst on the day-to-day foibles of dealing with technology.

Q: When's an empty toner cartridge not an empty toner cartridge?
A: When the printer manufacturer uses a chip to stop it working after an arbitrary number of copies.

I use my printer in what I always thought was a reasonably typical way for a small business. Mostly text pages with black text, but blue headings and hyperlinks. We also produce lots of newsletters and course documentation including graphics and in particular computer screen captures.

In order to get some idea of how much our printing costs (we often need to produce hundreds of pages of colour course documentation at a time so it can mount up), we check the number of pages printed before replacing our printer cartridges.

We used to have a Samsung CLP-500 and our use of the printer resulted in the cartridges exceeding their stated limits by a substantial margin – in the case of little-used yellow by a factor of 4 or 5. We reckon that this gives us a very reasonable cost per page of about 3.5p for a page with lots of text and the odd graphic or two.

So pleased with the CLP-500 were we that, when it came to replacing the OPC drum and Transfer belt, we opted to buy the new updated CLP-510 instead. Apparently little difference apart from a slightly improved specification. Or so we thought.

Actually, the CLP-510 toner cartridges have chips in them that prevent CLP-500 cartridges being used in the CLP-510 (inspite of them looking identical). Far worse than this, the chips apparently assume that any page that uses any of a toner colour is actually 5% covered in that colour. Once the printer has calculated that the cartridge is empty it refuses to print until it is replaced, even if it is actually three-quarters full, like our yellow cartridges will be. A colour cartridge for a CLP-510 costs about £65. So just under £50 worth of yellow toner will be finding its way to our local landfill site each time Samsung decides our cartridge should be empty when it isn't.

Apparently the chip is used to prevent the cartridges being refilled, as Samsung believes this can cause harm to the printer. It looks to me like the use of toner cartridge chips in this way is more likely to lead to people doing their best to find ways to refill the cartridges.