Grabiel
Its possible that the auto off feature may have been activated.
What this does is shut down the printer after a set period of inactivity this is done mainly to save electricity.
If you go into the setting menu on the printer look for either power settings or it may just have its own page on the menu for Auto-Off and see if that's enabled.
If it is NOT enabled have you checked the usually suspects? maybe a lose power cord or even a faulty power strip if you are using one?
When it happens what do you have to do to get it to turn back on just hit the power button?
Hope this helps
Step one: Check to see if Schedule Off is enabled
Follow these steps to set up the Schedule On/Off feature, or to check the current settings.
1.On the control panel, touch the Right Arrow (), and then touch the Setup icon ().
2.Touch Schedule On/Off.
3.Touch Schedule Off.
•If Schedule Off is enabled and you want to turn it off, touch Disable.