Thank you Enre and lewasabisushi for a very quick response,
Unfortunately my printer does NOT support ESC-POS emulation.
I tried "Text Printer" as suggested by Enre and the annoying "!a" code disappeared, BUT, it is consuming too much paper (seems printing 1 row and jumping the next one). Is there any way to correct "Text Printer" ? Otherwise I'll need to keep the annoying "!a" code in order to save paper.
Best Regards,
Glauberio