Memory full Toshiba e-Studio 16

[itech]

Hi. I need help with Toshiba e-Studio 16 copiers. When I put 20-30 double sided sheets into the RADF to copy them double sided see what happen. The machine start to copy. But it copies only the first 9 sheets (double sided) and the 10th is copied only one side.
The following message appears: MEMORY FULL.
The machine dosn't have a printer board, either network board.

Please help.