Apple LaserWriter 12/640 PS - Manual (Page 302)

Where fonts are stored
All fonts for your LaserWriter 12/640 PS printer reside in special places
within the System Folder. To install fonts in System 7, you drag them to the
System Folder. The Mac OS will automatically put them where they belong.
For versions 7.1 and 7.5 of the Mac OS, all the fonts are installed in the Fonts
folder within the System Folder.
The Fonts folder can contain a total of 128 font suitcases (described in the
next section), plus any number of PostScript fonts, up to the available storage
capacity of your hard disk.
IMPORTANT Fonts installed in other folders or in the top level of the System
Folder may not work correctly. Additionally, bitmapped and TrueType fonts
stored outside of suitcases may not work correctly.
303 Using Fonts With the Printer