Abstract: An insulating bushing of an electret condenser microphone is disposed on the rear side of a back electrode portion and abuts against the rear surface of back electrode plate. When a predetermined force is applied to the insulating bushing from the opened end of the case by way of a fixing ring and a printed circuit board, the insulating bushing deforms so as to fit into a gap formed between the inner peripheral face of the case and an end portion of the back electrode plate. Since the insulating bushing fits between the inner peripheral face of the case and the end portion of the back electrode plate, the back electrode plate is positioned and fixed with respect to the case in a state where the back electrode plate and the case are electrically insulated from each other.

Abstract: An electroacoustic transducer to be mounted on a board of a device, includes an anode conductive part which is in press contact with the board of the device, and a cathode conductive part which is in press contact with the board of the device, wherein the anode conductive part and the cathode conductive part are respectively placed at an axial center position or at predetermined positions in a radial direction to eliminate directionality in a circumferential direction.

Abstract: To attach or detach a process cartridge to or from a support member of an LED printer, an upper housing is angularly displaced and opened around a supporting position relative to a lower housing. As the upper housing is gradually opening relatively to the lower housing, the support member is angularly displaced around a connection position with the lower housing to be separated from the upper housing. Then, a used process cartridge can be detached from the support member and another new process cartridge can be attached thereto, thereby allowing such maintenance operation to be easily performed.

Abstract: A paper bailing apparatus for a printer which holds paper against the platen by a bail roller. In order to drive the bail roller from the release position to the bailing position, the driving force of the paper feed gear is utilized. The paper feed gear transmits the driving force to a bail gear which rotates the bail roller through an idle gear. The idle gear is held away from the paper feed gear and the bail gear in the ordinary state. A compression piece provided on a carriage moves the bail gear to the driving position. When the carriage is moved beyond the printing range, the compression piece moves the idle gear to the driving position. Once the idle gear meshes with the paper feed gear and the bail gear, even if the carriage is moved beyond the printing range, the interlocking is continued until the bail roller is moved to the bailing position.