The fastest way to print reports on dot-matrix printers is sending output to a File (REPORT FORM filename.frx TO FILE ASCII)and then copy the file.txt to printer.

My big problems is that I use some special characters like "ñáé", but it output others characters.

1- Cetins gave me This soluction

report form myreport to file myText ASCII
hd=fopen("mytext.txt",12)
lnSize = fseek(hd,0,2)
=fseek(hd,0,0)
lcText = fread(hd, lnSize)
=fseek(hd,0,0)
=fwrite(hd, ansitooem(lcText),lnSize)
=fclose(hd)

2- I tried using a Generic/text only printer, it did not work.

3- I tried with RUN COPY /B FILE.TXT TO LPT1:, it did no work.