What does the "Keep printed documents" option in my printer preferences do?
"Keep printed documents" specifies that Windows should not delete documents after they are printed. This allows a document to be resubmitted to the printer from the printer queue instead of from the program.
You might want to use this if you regularly reprint certain documents and want a quick way to do it without opening the original application that the document was created with.
To do this enable "Keep printed documents" in the printer preferences and print the original document for your first copy. Now if you open the printer in the printers folder you should see your document with a status of Printed. Right click on the print job you want to print again and select Restart from the popup menu, the document will now be sent immediately to the printer without using the original application.
Note that some print files can be quite large so if you print enough documents you will need to go through the printers on a regular basis and purge anything you don't need to keep. Just select the documents you want to remove from the queue, right click on the list and select cancel to remove your old jobs.