Abstract: A duplex printing apparatus includes a first conveyance device for supplying recording paper from a first paper supply tray to a printing device; a second conveyance device for supplying the recording paper from a second paper supply tray to the printing device; a third conveyance device for conveying the recording paper printed by the printing device to a paper receiving tray; a fourth conveyance device for conveying the recording paper to the second paper supply tray; a paper switching device disposed at the third conveyance device and operable to selectively send the recording paper printed by the printing device to the second paper receiving tray or to the fourth conveyance device; and a driving mechanism for the second paper supply tray which is operable to move the second paper supply tray to one position for receiving the recording paper from the fourth conveyance device and to another position in which the second paper supply tray supplies the recording paper to the printing device.

Abstract: In a lock in an injection molding apparatus for causing a toggle mechanism to lock molds, a servo motor is used as a drive source for driving the toggle mechanism to perform and control locking.

Abstract: A method for TIG welding by using a plurality of nonconsumable electrodes extending frm the tip of a TIG welding torch and one filler wire fed through a space between the electrodes, each electrode being independently supplied with power. A molten pool is formed by melting both the base metal to be welded and the filler wire by means of arcs generated between respective electrodes and the base metal. Melting of the base metal is mainly controlled by the arc produced by one of the plurality of electrodes while melting of the filler wire is mainly controlled by the arc generated by the other electrode.