Press [Home] () at the bottom of the screen in the center.
Flick the screen to the left, and then press the [User Tools] icon ().
Press [Tray Paper Settings].
Press [] repeatedly until [Printer Bypass Paper Size] appears.
Press [Printer Bypass Paper Size].
Press [Custom Size].
If a custom size is already specified, press [Change].
Press [Horizontal].
Enter the horizontal size using the number keys, and then press [].
Press [Vertical].
Enter the vertical size using the number keys, and then press [].
Press [OK] twice.
Press [User Tools] ().
Press [Home] () at the bottom of the screen in the center.