I picked up a HP OfficeJet v40xi from someone a while back. Lo and behold it apparently is not worth the effort to work on.
The HP OfficeJet v40xi is a printer/copier/scanner/fax machine. HP generally makes great printers, but in this case they let down the consumer.
The problem? Once it breaks, it's done, son.
What happens is that the print mechanism has a read error that causes it to not be easily fixable. Owners who have reviewed the machine before me call this the dreaded carraige jam issue. Once one gets this, the printer no longer works as it cannot print. Instead, the feed stops working because the print mechanism no longer can travel the full route of the print bar when requested to print.
I found my experience to be more or less the same with this printer.
It will travel the print bar (the thing that lets the printer go back and forth as it puts down ink) if you open up the cartridge service bay, but for some reason when printing is attempted, it won't do this. It instead gets stuck
Reading multiple complaints about this HP model, it seems to be a very common complaint. This complaint is littered across the internet - just Google the model number.
The lesson? Don't buy this used, and don't buy this printer new if expecting a long service life. The cost of getting service for the machine from HP (quoted at $125) is fiscally not worth it compared to getting another printer to replace the OfficeJet V40xi.
There are much better HP models that I have had positive experiences with that are superior to this one. For print/scan/copy action I would instead recommend the HP PSC All-in-One model range. You can see my review of this model here. I own one of those and have had two years of positive and worry-free experience so far.