Several technologies were introduced to enable this quality and speed: A related model, the Diablo 1620, includes a keyboard and strongly resembles a slightly overgrown Selectric typewriter.
Unfortunately for a typist (in either role), the daisy wheel mechanism hides the area just printed.
This made checking the copy for errors a bit more awkward and slow than on actual typewriters or on Selectric-based terminals.
The same mechanism was used in Xerox's 850 display typing system and 860PDS word processor, and was also sold to OEMs.
[6] This was so pervasive that at least one company lived by testing printers for full Diablo 630 compatibility.