Sounds like an electrical connection within the printer has shorted. Very fortunate you were in the house!
Next steps should be to contact Lexmark (hope you still have the printer) as they are should want to take it to investigate to find out if it was a one-off or something that could affect the rest of the Z32s sold.
Also contact whoever provides your household insurance and at the very least report it to them even if you don't wish to claim.
If Lexmark aren't interested then I would contact Trading Standards as I'm fairly sure they will be interested to hear what has happened.