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Refilling HP 5150 deskjet cartridges (no 56, no 57):

OK, so this isn't directly related to seedsaving. But there is a link - we print your seedsaving instructions on a nice little HP Deskjet printer, which even prints double sided. It wasn't very expensive, and works really well.

However, they are trying really hard to make serious money on the cartridges. In the past , you could just buy ink and refill your cartridge instead of buying a new one at some absurd price.

Now, with the new cartridges (that is Cartridge No 56 and 57, for the HP 5150, 5160, in fact all of the 5000 series deskjet printer), you cannot refill your cartridge! Well you can, but the printer will insist that it is still empty, and refuses to print!

Hmm. A little research shows that each cartridge has a serial number burnt into it. And the printer keeps track of how much printing has been done for that serial number, so it 'knows' that the cartridge you have refilled and put back in is 'empty'.

However, the printer only has a memory for 2 serial numbers. Aha . . .

the solution is simple:

You need to buy 3 cartridges.

and this way you can refill them as often as you like. (We are on our second litre of ink, and they only hold about 13ml each)

Why does this work?

The printer can only remember 2 cartridges at a time. So by cycling 3 around,
it has always forgotten about the first one by the time you get to it again.