Patent GB-1183627-A (GB)
Title: High Speed Thermal Printer.
Inventor: MERRYMAN JERRY DALE
IPC: B41J2/34
Filed: 1967-05-19
Abstract: 1,183,627. Selective printing. TEXAS INSTRUMENTS Inc. 19 May, 1967 [27 May, 1966], No. 23433/67. Heading B6F. [Also in Division G4] A thermal selective printer 10, Fig. 1, having a continuously rotating drum 12 on the surface of which is disposed a circumferentially spaced array of fifty thermal print heads P 1 -P 50 , Fig. 2, as described in the Specification 1,151,848 and subdivided into 120 axially extending matrices P 1 C 1  . . . P 1 C 120 , . . ., P 50 C 120 , each having 25 heating elements 20, is provided with a memory in the form of shift registers DSR 1  . . . DSR 50  underlying radially the matrices P 1 C 1  . . ., and capable of receiving and storing serial binary coded data and of converting the stored serial data to parallel data at a plurality of parallel outputs in the shift registers, the parallel outputs being coupled to activate selected heating elements in accordance with the serial data applied from a data source 44 and representative of a line of alphanumeric characters to be printed line-by-line on a thermo-sensitive recording medium 18 whilst it is in contact with the rotary drum 12 during one-half of its revolution. In operation power in the form of required potentials is applied over slip rings 30, 32, Fig. 3, to the shift registers, having a capacity of 3,000 bits, to fifty data gates DG 1  . . . DG 50 , fifty clock gates CG 1  . . . CG 50 , a ring counter RC having fifty bits b 1  . . . b 50 , which sequentially energize the clock gates CG 1  . . . CG 50  and to the matrices P 1 C 1 , . . ., P 50 C 120 . The data representative of a line of alphanumeric characters is supplied to the shift registers DSR 1  . . . DSR 50  in the form of a series of 3,000 binary code bits from the data source 44, through the intermediary of a slip ring 28, when the drum 12 is disposed at a station 50 at which time a pulse train from a low speed clock 34, 38 enables a respective one of the bits b 1  . . . b 50  of the counter ring RC through a slip ring 22 to open the associated clock and data gates CG 1  . . . CG 50  and DG 1  . . . DG 50 . The serial data is synchronized by means of a high speed clock 36, 40 whose clock pulse is applied to one input of the clock and data gates. In a modification each shift register DSR 1  . . . DSR 50 , (Fig. 7), is replaced by five DSR 1 a . . . DSR 1e , . . . DSR 50  . . . DSR 50e  shift registers each having a capacity of 600 bits. The 600 bit shift registers are loaded with the serial data simultaneously i.e. in parallel through a respective number of slip rings and data gates. The number of shift registers reduces proportionally the frequency of input of the serial data into the shift registers. The heating elements 20 which are energized at the station 50 are brought to their operative temperature prior to contacting the recording medium 18 at a position diametrically opposite the station 50, the actual impression of a character taking place during the period when the record medium 18 is in contact with the drum 12, i.e. during one-half of its revolution. (For Figures see next page.)