Apple ColorLaserWriter 12/600PS - Manual (Page 52)

4 Slide the paper under the bracket at the front of the cassette.
WARNING Never load a cassette with paper of the wrong size or type.
Doing so may cause a paper jam, damage the printer drum, or use toner
unnecessarily.
Load three-hole punched
paper with the holes toward
the back of the cassette.
Load letterhead paper face up.
Make sure paper fits under
these corner brackets.
You can push the paper down,
but don’t overload the cassette.
ABC
27 Setting Up the Color LaserWriter 12/600 PS