RICOH FT 7650 shuts itself off when not in use after 45 minutes

Enter in the user mode:
1.Press the Clear mode key.
2. Press the Clear/Stop key more 4 sec untill the user tool menu appears on the touch panel.
3.This copiers has more 12 user tools.You can see 5 user tools on the display at the same time.Use these keys to see the rest .
4.AUTO RESET: the copier return to the initial condition autommatically after your job is finished.(after 60 sec)
5.SCREEN SAVER :when the copier does not detect anyone operating it for selected time the display turns OFF.(60 sec).
6AUTO OFF:Whwn the machine is used after weekly timer has turned it OFF the copier will turn itself back OFF after the selected time.The auto OFF time can be set from 1 to 999 minute or the function can be turned.(I recomanded setting level OFF).

Your machine has a max 240 minute shut down sequence. In other words 4 hours is the max it will stay on without usage. go to user tools, timer features.