One embodiment of the present method and apparatus for user-moderation of an online chat room in which a plurality of users are exchanging messages includes providing the chat room and controlling a manner in which the users send and receive the messages in the chat room in accordance with user feedback relating to the messages. A sheet supply device supplies the sheet stacked on the sheet supply tray. At least one of the insulating terminal block and the end cover has a heat shield plate member laterally extending through a radial space between the cooling fins and the brush unit in a direction substantially parallel to the axis of the rotary shaft.