Canon Pixma ip4500 problem

[Dave Deering]

I have an ip4500 which won't print, 4 orange flashes CLI-8C not recognised, on investigation the cartridge is not illuminated, have tried numerous times to reseat it without success still no light.

I've tried it in the next slot and the cartridge illuminates, the one I took from that slot, which lights up in it's own slot does not illuminate in the CLI-8C slot, has anybody any suggestions as to what is wrong, they are all genuine Canon cartridges.

Thanks

Dave