It often happens, and sometimes you can be waiting for ages. There is a way round it though.

Open your Print Queue File (it's in the sys tray when the printer is working), go to Printer and click on Pause Printing. This enables the printer to stop working on that document almost immediately, and start printing out the next.

The main reason for this delay is the amount of memory INSIDE the printer, this has to empty out before the next document begins to print.