When Wi-Fi Direct (Simple AP) connection disabled, all computers and smart devices connected to the printer in Wi-Fi Direct (Simple AP) connection are disconnected. If you want to disconnect a specific device, disconnect from the device instead of the printer.
Select 
on the printer's home screen.
To select an item, use the 
buttons, and then press the OK button.
Select Wi-Fi Direct.
The Wi-Fi Direct information is displayed.
Select Start Setup.
Select 
.
Select Disable Wi-Fi Direct.
Follow the on-screen instructions.