Xerox 720

The Xerox 720 was another version of the 914 copier, and the only difference was...

The 720 Copier / Duplicator, as it was styled, was a double speed version of the Xerox 420. By the re-gearing of a more powerful main motor, throughput was doubled from 7 copies per minute to 14 copies per minute. Output speed was only maximised to 17 cpm. with a later field modification, known as the Short Scan mod.

The 720 came with Differential Billing as standard, complete with the steel tube, platen cover handle, a flush front door, a new two tone grey paint job and a 'Collator Unit' which was a set of 10 shelves designed, in the main to make the machine look different.

Short scan was achieved by initiating optical 'Flyback' at the normal A4 length, thus saving about 2 inches per scan and speeding up the machine to, a theoretical, 17cpm. It was rarely, if ever, used.

However, speeding up the machine was not simply a matter of gearing.
A faster, and less robust, drum coating needed to be used, along with brighter lamps and increased corotron currents. An uprated developer also had to be formulated and a bigger, hotter fuser unit fitted. Then, the drum cleaning unit had to be uprated and a larger capacity filter bag fitted.

Thanks to Stuart Yearsley for providing this information.