Printer with front and back heads

[Yuri Albuquerque]

Sorry for the silly question again, but I couldn't manage to do this by myself.

I have a printer with a front and back head, which means it prints on both sides of paper. I want one of the pages to be printed on the front, while the other is printed on the back of the paper.

But the buffer of the printer only has 4K. So, when I send the commands by page, it prints a whole page before it starts the other page.

Is there a way to print a line from one page and then a line from the second page? I tried to do that with simple commands, and the filter always failed.

Thanks for the help.