GB1297604A - - Google Patents

Abstract

1297604 Document sorter; recognizing character forms; character recognition INTERNATIONAL BUSINESS MACHINES CORP 26 May 1971 [26 Aug 1970] 17108/71 Headings G4M and G4R A document sorter has means for scanning information on a document to be sorted and developing analog signals from the information, the signals being integrated and analysed to provide signals on one of a plurality of lines to indicate the character scanned. Documents are fed one by one from a stack past three document sensors to a read head in which analog signals are induced. The signals are amplified, clipped, filtered and fed to a voltage controlled amplifier whose output feeds a peak detector controlling the amplification of the amplifier. The signals are further amplified and fed to a series of integrators. A peak detector starts an oscillator and control ring which divides the read cycle into 8 segments so that the character waveform is divided into seven segments which are integrated in 8 integrators, the first integrator intergrating over all time zones, the second over all but the first zone, the third over all but the first two etc. with the integrals being stored on capacitors after successive integrals are subtracted to give the integral for each zone. The data is analysed by fourteen correlation networks and the maximum amplitude produced is used to identify the character and set a character latch. The data is also checked by examining peaks in the waveform from particular time zones and the two sets of data are compared to produce an error signal. Character simulation circuits are provided to check the circuitry. Timing pulses for the transport mechanism are produced in synchronism with the drive system and are counted. Three sensing heads provide signals to control circuitry to identify the positions of the documents and can identify insufficient spacing between cards or an empty hopper or a jam. The sense signals reset a counter which is arranged to produce a jam indicating signal if the count proceeds above a fixed value. The documents are sorted into required pockets and if an error signal is produced the documents are supplied to the last pocket in the row.