The standard parallel printer devices (/dev/lp, /dev/lp0, /dev/lp1, and /dev/lp2) send a printer initialization string (init) the first time, and only the first time, the device is opened after the system starts up.
Some parallel printers require initialization every time a file is received for printing. Others require an init if the printer is turned off and back on again (for example, after changing paper or ribbon).
If you need to initialize the printer more often than the standard devices provide, you can create an additional device file for the parallel port. Then, use this init device file to initialize the printer when necessary.
This associates the parallel init device, /dev/lp0i, with printer_name.
If your printer requires an init every time a file is sent (and it does not have a large internal text buffer), you can use the /dev/lp0i device all the time. The lp(C) command then sends an init every time you send a file to the printer.