Abstract: A fibre-type light wavelength conversion device for changing the wavelength of an incident beam and emerging it as a beam having a predetermined wavelength includines a core and a cladding layer around the core. The device is characterized by the provision of a transparent conical layer provided around the cladding layer, the conical layer having a diameter increasing at a predetermined inclination from an end of incidence toward an end of emergence. According to a further feature the conical layer has a refractive index substantially the same as the cladding layer, and the inclination of the conical layer is set to be a half an angle of emergence of a beam emerging from the cladding layer with respect to a wave guiding direction.

Abstract: In printing heads for a dot line printer, a plurality of which are arranged in line on the reciprocal frame and impact printing wires toward a platen by the driving force of electromagnets excited with the basis of the printing commands, the printing heads for a dot line printer includes electromagnetic actuators including shells which contain and fix cores being wound driving coil around therein and base plates which are attached to the shells in order to close up their opening sides, and forming the tightly closed magnetic loops, and printing springs one ends of which are fixed and supported by supporting portions extended from the base plates, the top ends of which fix armatures at the postion facing to the cores.

Abstract: A method for controlling printing impact in an impact type dot printer which controls printing impact energy to be increase in case of normal density imprint function and to be decreased in case of high density imprint function in the controlling means of the impact type dot printer in which the printing stylus strikes the printing paper so that the printing paper can be prevented from being damaged during the high density imprint function.

Abstract: A printing head apparatus for a dot printer including a frame and at least one printing wire unit which is secured to the frame. The printing wire unit has an electromagnetic actuator and a printing spring with one stationary end and a printing wire attached to the other end thereof. The printing spring carries an armature at an appropriate central portion thereof facing the core of the electromagnetic actuator. The printing spring is flat and tapered toward the distal end, and a bent portion is provided on the flat portion for securing the printing wire, while an indented portion is provided on the base portion of the printing spring. A wire mask enables the ink ribbon to be smoothly fed.

Abstract: A method of dot-printing underline or the like employing a print head and power source with relatively small capacity. The reciprocation of the print head is divided into a plurality of travels by the command of divisional print so that the required underline print is performed by the collected dot prints being printed at intervals on each of a plurality of travels of the print head. A rest time will be provided between each printing actions at intervals of the print head to reduce the capacity of a power source employed for driving the dot pins in the print head.

Abstract: A paper feeding apparatus used in shuttle printers including drive means for moving a print sheet and a paper holding spring for holding the print sheet on a platen to apply a back-tension to the print sheet when it is being moved. The feeding apparatus further includes friction means disposed opposed to the print sheet at a position forward of the platen in the direction of feeding, pressure spring means located opposed to the friction means, and a lever for biasing the pressure spring means against the friction means. The platen is movable between a first position where it is engaged by the paper holding spring and a second position where the plate is disengaged by the paper holding spring. The biasing lever has its tip placed in non-contact with the platen when the platen is engaged by the paper holding spring, whereby the lever can be engaged by the platen to separate the pressure spring means from the print sheet when the platen is moved from the first position to the second position.