Clip 5 of 6 clips from a 1987 Apple training Video for resellers. Parts 1-4 are titled "Training for the Laserwriter II Family of Printers."
1. Extending the Lead
2. The Print Controller
3. Imaging
4. Xerography

Part 5 on the tape is "An Introduction to the Apple MIDI Interface" which I have split into clips 5 and 6.