I found an interesting problem.
When I close the ADF the display say "Original left on glass", but the glass is empty.
Some days before this I found this problem another copyer.
That is another C350 then I clean the ADF's white something that cover the glass when I close the ADF, ang the problem is gone.
But when I clean the white something on the ADF nothing change.
Ok,I check the original size sensor maybe put a another (2nd) original sensor, but haven't 2nd sensor.
When I place a A4 stand paper the size sensor can't inicialize the paper size,but when I place a A3 paper the sensor ident good the paper.

ps.sorry for my english