Again this (particularly #1) sounds like the printer driver crashing. If Qimage shuts down after the unclog job is sent to the printer, that's the point where the printer driver should be returning control back to Qimage and about the only thing that can cause Qimage to crash at that point is the driver since it is happening after Qimage has finished processing the job. It sounds like the driver or Windows spooler is crashing just after receiving the job... and that crash will take Qimage with it because Qimage is the "calling" program (to the driver).
Edit: Also since you indicated having trouble after printing, you could try changing your printer to "Microsoft Print to PDF" and print to that and see if the problem goes away. If it does, it's almost certain the problem lies within your printer driver. If you still have the problem, it's more likely to be a problem with the Windows spooler and a Windows update could be the issue (many Windows updates in the past have broken printing only to be fixed in the next update).
Mike