Ink cartridge problem

[rubymack]

Never had a problem with ink cartridges until my last two purchases.  I replaced the 920 cartridges, blue, yellow, cyan and black. I put the cartridges in like always and the printer gives the message " cartridges are missing or damaged."  The first time this happened, I took them out and reinserted them and I got the same message on the blue and cyan. I reinserted a second time and everything was OK.  Last week purchased new HP replacement cartridges and got the same message on all four colors. I must have taken them out and put them back in at least 10 times over a one hour period and finally all but the black took.  I was about to give up after 4 or 5 more tries with the black, but had one more idea.  I took a Q-tip  and dabbed a little alcohol  on the end and swiped it across the contact on the black cartridge and damned if it didn't work.  Have they switched to another manufacturer which is causing a problem?  Anyone else having this problem?

[2pods]

I'm having the same problem with a Magenta cartridge, but the swabbing didn't work for me. So maybe there's more than one type of fault ?