Solutions
Hold down the button for a little longer. If you still cannot turn off the printer, unplug the power cord. To prevent the print head from drying out, turn the printer back on and turn it off by pressing the button.
Solutions
When Auto Power On is enabled, it takes longer to turn off the power.
Select On to turn on the printer automatically when it receives a print job over a USB-connection or a network connection. If the output tray is stored, slide it out manually and printing will start.
Enabling Auto Power On increases power consumption slightly in standby status when compared to turning the printer off completely. Also, it takes longer to turn off the power. Leave the power cord plugged in when using this feature. If you unplug the power cord, make sure the power light is turned off.
Use the Power Off Timer setting if you want the printer to automatically turn off when the print job is finished and a set time period has passed with no operations performed. This is useful when printing from a remote location such as over the Internet.