Abstract: An impact head includes an arm member moving to a protruding position when a magnetic flux is generated and to a return position when the magnetic flux disappears; an impact member connected to the arm member for protruding when the arm member moves to the protruding position and returning to an original position when the arm member moves to the return position; and an urging member for urging the arm member with a restricted urging force when the magnetic flux is generated and urging the arm member to the return position when the magnetic flux disappears.

Abstract: In order to realize a weight saving and prevent a concentration of stress to thereby obtain durability endurable for high-speed printing, an armature of the present invention has an arm that is formed into a long-sized plate-like shape and holds a printing wire at its end section and a magnetic circuit forming member that is positioned at the other end at the side of the printing wire and has a projecting section projecting from the arm toward the direction in which the printing wire extends, wherein a first inclined surface that gradually inclines toward the projecting section in the direction in which the printing wire extends and a concave-shaped first curved surface that communicates with the first inclined surface and bends inward with a predetermined curvature to reach the projecting section are formed at a first end face of the arm at the side of the projecting section.

Abstract: An armature manufacturing method of forming an armature including an arm holding a printing wire, and magnetic circuit forming members attached to the arm places the magnetic circuit forming members on the arm with a resistive layer of a resistive material having high electric resistance sandwiched between the arm and each of the magnetic circuit forming members, and welds together the arm and the magnetic circuit forming members with the resistive films sandwiched between the arm and the magnetic circuit forming members by spot welding. The arm and the magnetic circuit forming members of the armature can be joined together by welds having a high weld strength.

Abstract: A method of controlling noise in an impact printer that modulates the input pulse to the power amplifier of the printer. The resulting current waveform is then applied to the print wire solenoids. The final shape of the force input to the platen reduces or spreads the spectral envelope containing problem harmonics and acoustic output noise.

Abstract: An ink density closed loop control system for an ink ribbon of an impact printer having a reservoir roller formed of an ink absorbent material with at least one or more channels within the reservoir roller fluidly connected to a pump and ink supply. A transfer roller can contact the reservoir roller for imparting ink to the ink ribbon. A sensor senses the relative amount of ink on the print ribbon and an electrical drive responsive to the sensor drives the pump for a flow of ink to the one or more channels. The sensor can sense ink on different segments of the ribbon and, with two or more channels in the reservoir roller can distribute ink to two or more segments of the reservoir roller depending upon the ink sensed at a particular segment of the ribbon. A further enhancement of this invention provides a multi-viscosity ink to compensate for changes in ambient temperature conditions.