Patent GB-1138480-A (GB)
Title: Improvements in or relating to high speed printers
IPC: B41J1/20
Filed: 1966-11-16
Abstract: 1,138,480. Selective printing. POTTER INSTRUMENT CO. Inc. 16 Nov., 1966 [24 Nov., 1965], No. 51276/66. Heading B6F. Machines with type on endless bands.-In a high-speed printer with a belt of type movable at a constant speed across a print line and a series of selectively operated print hammers arranged at letter-space intervals, the chain is formed of a non-metal e.g. fibre glass reinforced neoprene with uniformly spaced teeth on its inner surface for engaging a belt drive. Framework; detachable ink-ribbon assembly.- The various assemblies viz, the support structure for the print hammers assemblies 24, 25, the type belt and ribbon assembly 26, the carriage adjustment assembly 30 are each provided on a similarly formed extruded channel members 36, 38, 40 respectively and are individually assembled into spaced end plates 20. Type-belt.-The type-belt 218 is shaped with transverse teeth 222, Fig. 14, over which are fixed detachable type 226. The type 226 are channel shaped at their ends 228 to receive the belt 218 which is placed in the channels by temporarily bending. The belt is driven by sprockets 156, 158 adjustable relative to one another on pulleys and driving belt 196, 194 and a motor 192. The assembly is adjustable about a pin 184 by means of screws 186, Fig. 2, on pillars 188, Fig. 5, so that the type-belt is evenly spaced from the paper over the whole width. The type-belt is guided in a channel 238, Fig. 5, in a bar 237. The channel has an elongated bar magnet 240 to constrain the type slugs 216 in light sliding contact. Alternatively the belt may be guided by accurately machined guiding lips (250) engaging notches (250) in the type, see Fig. 12, not shown. Carriage movement adjustment.-The typebelt and ribbon assembly 26 is movable relative to the hammer assemblies 24, 25 to facilitate paper fitting by means of a rack 104 and pinion (108) on a hand operated lever. The pinion is on a shaft carrying a stop lever 122 engaging an adjustable stop 126, mounted in a further extruded channel 40. The assembly 26 is mounted on the channel member 38, Fig. 4, resting on spacer blocks 86 screwed to rails 84 carrying the racks 104. The rails are held by lower rollers 94 and adjustably mounted rollers 96. The adjustment of the stop 126 alters the impact pressure of the hammers according to the number of webs being printed. Ink-ribbon feed and guides.-An ink-ribbon 140 is fed by separate reversible motors (142) from spools 136, 138 and guided across the printing line past guide posts on the channel 38. Maximum ribbon wear.-The sub-assembly 134 for the ink-ribbons mechanism is centrally pivoted on a dowel 144 in the channel 38 so that it can be inclined slightly with respect to the type belt so that the entire width of the ribbon is used during printing. Pin tractor web feed.-Transversely adjustable pin tractor assemblies are mounted on a guide rod 254 fixed on end plates 20 and driven by a splined shaft 256 through a coupling 338 which permits slight misalignments between the shaft 256 and drive shaft 336. Shaft 336 is intermittently rotated as required through a clutch brake unit 334 and a continuous drive from a flywheel shaft 332 and an electric motor 324. A lower idler sprocket wheel 274, Fig. 17, for each pin tractor is adjustable by a tractor tensioning knob 276. After the perforated web is threaded through the machine and placed on the feed pins it is held there by pivoted guides 286. Special paper feed.-The web is fed as required under the control of a perforated loop and a bank of photoelectric cells (302), Fig. 18, not shown, and a bank of electric lamps (318), in a hinged guide unit 308. The perforated loop is fed by the rear path of the pin-tractor feed. Paper guides.-After the web has passed the printing position it is guided by curved wire rack 293 mounted between the end plates 20 so that the web clears the components at the rear of the machine.