Do you have an inkjet printer at home? If so, there's a decent chance that it's an HP Deskjet or Photosmart of some kind, and you'll be familiar with the standard HP design: a paper runs through the printer towards you as a moving print-head swishes back and forth, building up the image as it goes.

You may, if you're lucky, even have an A3 inkjet printer, in which case it'll look much the same but about twice the size. And, if you're really into photography, you may have forked out for an HP Designjet - again, these look much the same, but run to four or so feet wide. And that's presumably about as large as inkjet printers get. Isn't it?

As it turns out, the answer is an emphatic "no". Today I was taken to meet the HP Designjet L65500, which looks like this:

The effect of seeing a printer like this in the flesh is a little like being hit by a shrinking ray: it looks just like a gigantic DeskJet. To give some idea of how big it is, the printer takes six ink tanks, each one holding three litres of ink, it takes around three seconds for the printhead to move across the page, and it can produce 800 square feet of print per hour. These printers aren't generally available yet, but when they appear you could expect to pay around $100,000 for one.

And that's not even the biggest inkjet hidden away in HP's San Diego lab. Meet the HP Web Press:

The web press is the size of a few cars parked end to end, and can churn out 400 feet per minute when printing on both sides of 30 inch wide uncoated paper, using technology that's essentially the same as the printheads inside a desktop inkjet. So, next time you have to fork out £15 for a new ink cartridge, spare a thought for anyone who has to keep one of these running.