Hi SureWhyNot... Thanks for helping me! I discover my error. The changing of the font happens when you try to export a PDF via CAIRO ... BUT .... now I'm doing in this way: I print the file choosing PRINT TO FILE and I create a PDF file. In this way It works without font's changing and with a perfec...

you are right. I import a PDF file, then i draw on it and, finally, I export it.

Is there a way to avoid the font's changing?

Why, exporting a PDF, inkscape changes the font of the text?

How can I avoid it?

Thanks in advance