Quite likely for the same reason buttered bread always falls buttered side down.
Seriously, perhaps you could consider providing a few more details? That would help others help you better.
To add to Noel’s post, would you expect a mechanic to be able to determine the root problem just by telling them: »My car won’t start.«?
Maybe you could read this:
As the others said, we need a lot more info - operating system, printer, printer driver version, settings and what have you...
I've just encountered the same problem. All working okay last week, now if I press print there is an instant crach. Windows 7, CS6, Epson Stylus Photo R1900 and Epson Stylus BX635FWD. I've changed nothing in the past week, I don't think I've even let any updates install.