It depends on your printer. If the printer recognizes Control-L as a command to skip to the next page, then including CHR (12), as in your try #3, is all you need. (This may be an optional setting on your printer.)
If that doesn't work, then find out what your printer expects instead, and include that instead.
the printer is epson lx 300 dot matrix printer
I've tested the printer by printing the file from notepad it does the FF correctly
can somebody send me a sample file with FF char (text file .txt)
here is my file it has the FF char