Use the following procedure to have paper fed alternately one sheet at a time from two trays. For example, use this function if you print onto OHP transparencies and want to have paper from another tray inserted between each sheet.
Open the printing preferences dialog box after creating a document in an application.
Click the Cover/Slip/Designate menu on the Detailed Settings tab.
Select the Insert Slip Sheet After Every Page check box, and then select the paper tray loaded with paper for the slip sheet in the Input Tray: list.
In the Print Mode: list, select the print mode
Slip sheets not printed on is not included in the print count.
After making any other necessary settings, click OK to close the printing preferences dialog box.
Start printing.