How do I change the Power Off Timer setting in Mac OS X?
You can use the printer software to change the time period before the printer turns off automatically.
Do one of the following:
Mac OS X 10.6/10.7: In the Apple menu or the Dock, select System Preferences. Select Print & Fax or Print & Scan, select your product, and select Options & Supplies. Select Utility and select Open Printer Utility.
Mac OS X 10.5: In the Apple menu or the Dock, select System Preferences. Select Print & Scan, select your product, and select Open Print Queue. Select Utility.
Select Printer Settings. You see this window:
Select the time period you want as the Power Off Timer setting.