Your FoxPro program is DOS based: On its own it can only print to a parallel (LPT) or serial (COM) port. It sends ASCII data streams to a printer. The data streams contain so called escape control sequences to instruct for instance the printer to print in bold. Those sequences differ from the LQ570 (ESC/P) and HP 1320 (PCL), the LQ570 doesn’t understand PCL, HP 1320 no ESC/P.
You would have to connect the printer to the parallel port, and eventually change the ESC/P codes used by your program to PCL. Windows printer drivers are unrelated, those don’t support ASCII data streams at all.
To print to a Windows installed printer - so use a Windows printer driver - you would need a DOS-to-Windows print processor like DOSPRN (https://dosprn.com/dos-print.htm). Such a program will capture the ASCII data streams sent to a printer port (LPT or COM), convert it to input for a Windows printer driver, and send it to that printer.
This of course only works for Windows 32 bit. Windows 64 bit won’t even run DOS programs, then you would have use a virtual Windows 32 bit machine, or a DOS emulator that supports printing like vDos (https://www.vdos.info).
