Patent GB-998711-A (GB)
Title: Improvements in or relating to phototypesetting apparatus
IPC: B41B21/16
Filed: 1961-06-28
Abstract: 998,711. Photographic type-composing apparatus;. HARRIS-INTERTYPE CORPORATION. June 28, 1961 [June 30, 1960], No. 23454/61. Heading B6W. [Also in Division G2] The apparatus includes a rotatable character carrier having a plurality of fonts of master characters arranged concentrically about the axis of rotation of the carrier, illuminating means arranged to flash illuminate one character at a time and to produce a substantially stationary light beam forming an image of the character, an optical system for directing the image-forming light beams along a path to focus in a common plane, and font-selector means including light-deflecting means between the carrier and the optical system to direct the image-forming light beams from a selected font into said optical system whilst maintaining constant the optical path length in the system. Preferably the illuminating means comprises a single light source and means operating with the font-selector means to direct light from the light source towards the chosen font path. A pi character plate may be mounted adjacent to and coplanar with the character carrier and may co-operate also with the light-deflecting means both of the fontselector and for the light source; while a second rotatable character carrier may be replaceably brought into the operative position. As shown, the apparatus employs a rotating disc 10 bearing two concentric fonts 12, 14 of characters, each font having its own set of character width codes 35 and character identifying codes 15, as described and claimed in Specification 998,715. The character-identifying code marks are as disclosed in Specification 912,201, and are read by photo-cells 17, 18, which feed information to the selector circuits 20 as in that Specification, and the two sets of width code marks are read by separate sets of photo-cells 38 which are connected alternatively through a change-over switch 122 to the character width computer as in Specification 998,713. Selection of the desired font and its illumination by light source 28 is achieved by pivoting a prism pair 45, 46 about the optical axis 30 of the illumination and image projection system. The prisms are supported on shelves as 108 formed on arms 103, 105 joined by a saddle 102 and pivoted on trunnions as 109 in a U-shaped bracket 98 fixed on a carriage 95 adjustable by means of a dove-tail web 96 engaging in a mating slot 92 on a bed 90. The trunnions 109 are hollow as shown at 110 and they and the adjacent ends of the prisms are centred on the optical axis 30, the carriage 95 being adjusted so that the disc runs freely between the prisms. In the rest position of the font selector the outer ends of the prisms cooperate with the font 12 but on activating air cylinder 115 the prisms are rotated so that their outer ends embrace font 14. The characters are arranged with their base and left-hand vertical reference lines intersecting on the axis 30 so that changes in size produced by adjustment of the lenses 32 do not upset the proper positioning of the characters in the line. If pi characters are to be employed these are set up in a frame 130 on a slide 125 movable parallel with the optical axis to a position in the plane of the character disc adjacent its rim. Then by operating air cylinder 135 the prisms are rotated still further to embrace the frame 130 and so allow recording of the pi character. When cylinder 135 is deactivated, the prisms return to the font setting previously selected. If more than two fonts are necessary, a second character disc 10a is provided. The two discs may be rotatably carried on a T-member 57 attached to a shaft 55 supported in vertical standards as 52 and bearing a cross arm 80 connected to the pistons of cylinders 84, 85. The two discs are driven together by a belt 70 connecting pulleys 68, 69 on the disc shafts, a continuously driven friction wheel 75 engaging friction wheels fast with whichever of the pulleys is brought adjacent it by activation of the appropriate cylinder 84, 85. The apparatus may be operated from a control tape 150 passed through a reader 152 which operates both the character selector 22 and the font control 155 which also controls pi character operation. This control 155 operates as appropriate electromagnetically-operated valves 158, 159 controlling disc selection and similar valves 166, 170 controlling positioning of the prisms. Specifications 985,041 and 998,712 also are referred to.