Abstract: A switching device is provided for a sewing machine for switching operation of the sewing machine from a zigzag stitching to embroidering or vice versa. The switching device comprises a rotatable disc fixedly mounted on an output shaft of a stepping motor and a sliding member that movably connects one end of a transmission rod via a pin, the other end of which is connected to a needle bar supporter or a fabric feed device, with the rotatable disc so that the one end of the transmission rod is movable between a first position on the rotatable disc which coincides with the center of rotation of the rotatable disc, and a second position on the rotatable disc which is spaced apart from the center of rotation of the rotatable disc.

Abstract: In a wire-dot impact type printer a cylindrical platen and a printing paper are rotated or transported at the same rate, by connecting them to a single and common electric motor through a first and second transmission mechanisms, respectively. The first transmission mechanism directly connects the platen to the motor to cause the former to rotate together with rotation of the latter in any direction, whereas the second transmission mechanism includes a clutch composed of a first and a second members rotatable about a common center axis but separately from each other in which the first member is caused to rotate together with rotation of the motor in any direction while the second member is caused to rotate together with the first member being rotated in one direction but prevented from rotating when the first member is rotated in the other direction. In the latter case the platen is rotated for color changing operation, but the printing paper is prevented from running through the printer.

Abstract: A printer of a wire-dot impact type is provided forwardly of the housing an inlet opening for introducing a printing paper to the inside and has an outlet opening provided at a rear side of the housing for discharging the printing paper to the outside. The printing paper is transported by cooperation of a tractor arranged near the outlet opening and a feed roller arranged near the inlet opening, to thereby run inside the housing in substantially a straight path of travel from the inlet opening to the outlet opening, during which the printing paper is printed by means of a platen and a printing head, both provided between the feed roller and the tractor. A pair of guide members are provided between the feed roller and the printing unit and between the printing unit and the tractor, respectively, to thereby feed the printing paper along the straight path of travel.

Abstract: The printing mechanism of a dot matrix printer includes a platen provided on its jacket with elongated ink impregnated sintered bodies each extending over the entire length of the platen. The platen is movable in the printing direction at one side of a printing paper. A printing head moves in the same direction but at a different speed at the opposite side of the paper so that impact wires strike different points on a preselected sintered body during the printing of a line.

Abstract: A printer of the dot impact type which prints by guiding a printing paper between a printing head and a platen which is composed of a plurality of sintered bodies containing inks of different colors, and attaching the ink containing body to the printing paper, comprising a platen which changes the ink color by rotating the ink containing sintered bodies; a drive device including a one directional clutch which sends the printing paper in a normal direction by clockwise rotation of a motor, and changes the colors by counterclockwise rotation; and a switching mechanism which connects the one directional clutch to bi-directions when the printing head is moved outside on available printing scope.

Abstract: In a printer which guides a printing paper between a printing head and a platen having ink containing bodies, and prints on said paper by pressure of the printing head; an attaching device for a platen body of the printer, wherein rotation control of the platen for changing ink color is made via a square shaft which is provided independently of a platen shaft having a rotatable, slidable plurality of bodies containing inks of different colors, and the platen is laterally moved via a supporter which slides along the square shaft, and the platen body comprising the platen and the platen shaft is structured independently of said rotation control and said lateral movement.

Abstract: An impact type color printer is provided a control circuit which produces a random digit signal each time the printer is connected to a power supply, according to which random digit signal a platen is rotated so that one of plural impact sections axially arranged in each ink saturated member of different color is selected at random and positioned just opposite to a printing head to be subjected to impact thereby for printing operation.

Abstract: In a wire-dot impact type printer, a single electric motor is employed for rotating a platen provided at a periphery thereof with a plurality of ink saturated members to thereby change a color to be applied to a printing paper, as well as for rotating tractors cooperated with feed rollers to thereby transport the printing paper in a predetermined direction. A transmission mechanism for transmitting rotational movement of the motor to the tractors comprises a switch disc rotated together with the motor and having a circular periphery thereof which is half toothed and half untoothed, and a clutch composed of a first rotating disc rotated due to engagement with the toothed half portion of the switch disc and a second rotating disc capable of rotating together with the first rotating disc being rotated in one direction to thereby cause the tractors to rotate for the paper feeding operation, but prevented from rotation when the first rotating unit is rotated in the opposite direction.

Abstract: A device for adjusting printing paper tension in a printer comprising a switching member connected to a plurality of pinch rollers by a connecting structure whereby the pinch rollers are caused to separate from, or contact lightly or strongly with a feed roller of a printing paper feed device when the switching member is rotated, resulting in the required paper tension.