The Sinclair ZX Printer
The ZXPS was designed for and fully tested with the Sinclair ZX Printer.
The ZX Printer was introduced by Sinclair Research Ltd. in 1982, sold for $99.95, and works on the ZX80 ZX81 and TS1000.
ZX Printer References:
The ZX Printer Instruction Manual can be found here: https://www.zx81.nl/dload/pdf/Printer-Instructions.pdf
The ZX Printer Serivce Manual can be found here: https://spectrumforeveryone.com/wp-content/uploads/2017/08/ZX-Printer-Service-Manual.pdf
The ZX Printer Belt
The ZX Printer belt seems to disintegrate over time. replacements can be 3D printed or purchased online. Here are some references.
3D Printing
Sinclair ZX Printer Belt on thingiverse https://www.stlfinder.com/model/sinclair-zx-printer-belt-lwktcrhu/4367663/
https://www.thingiverse.com/thing:4822567
Repairing ZX Printer Videos
A sad, broken ZX Printer: Diagnosis, fixing and testing. https://www.youtube.com/watch?v=RHOXv2exdak
3D Priinted Belt https://www.ebay.com/itm/156070756325