I have a HP OfficeJet Pro K8600, which isn't playing ball.

It started about 2 weeks ago printing nothing but the first inch of a document. couldn't seem to fix the issue so contacted HP they sent out a replacement printer set that up turns out the print head is gone replace that, get the print setup on the network first print works fine, kids then trying to print to it and its back to printing just the first inch, I totally re-installed the printer on the server, new IP address etc, but no joy. Any seen this before?