We created the Retro-Printer module some years ago, and have been improving the software to meet a wide range of applications.
The ZX Spectrum and ZX81 could use it as it stands if you have a centronics interface as the module emulates an Epson printer, or even HP PCL, depending on what the centronics interface supports.
However, is there sufficient information about how the ZX Printer works to make a simple adaptor for the ZX Spectrum / ZX81 to work with it via the expansion slot I wonder?
Replacement Printer for the ZX Spectrum / ZX81
Replacement Printer for the ZX Spectrum / ZX81
Rich Mellor
RWAP Software
RWAP Adventures
SellMyRetro
Retro-Printer Module
Also Involved in:
Icephorm
RWAP Software
RWAP Adventures
SellMyRetro
Retro-Printer Module
Also Involved in:
Icephorm