If you can talk to the printer via Serial commands (which might be possible via the ‘COM8’ port interface), *and* if the printers still respond to bitmap commands, then you might be able to use them with our software.
Google’s translation of http://atol.ru/products/kkt/fprint/fprint-55k.html
seems to say that the printer has “increased memory for graphics”, which implies that it’s at least possible to send bitmap data to the printer, but I cannot find a manual that would outline the specific commands required.
In terms of what you’d need to find and do to make a printer of this model work:
* Find a manual which outlines the bitmap commands the printer will accept
* Write some software which runs on your Windows computer to poll a server which includes that software, and pipe any returned data to the serial interface that the printer is connected to.
Hopefully that makes sense, but it’s clearly quite a technical challenge. If you need further help I can try, but it’ll be quite limited without having access to an actual printer, along with the documentation required.