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Optical Card Reader Using Scanistor Mode of Operation

IP.com Disclosure Number: IPCOM000095716D
Original Publication Date: 1964-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Malek, K: AUTHOR [+2]

Abstract

This card reader uses the scanistor mode of operation for detecting punched hole information. The scanistor is a semiconductor device having photosensitive properties. When light is directed on a given point on the semiconductor body, the photocurrent at that point increases. The change in photocurrent at points along the semiconductor body are scanned by an applied ramp voltage. In this system, a scanistor 7 is included which is responsive to light passing through the holes of a punched card, not shown.

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Optical Card Reader Using Scanistor Mode of Operation

This card reader uses the scanistor mode of operation for detecting punched hole information. The scanistor is a semiconductor device having photosensitive properties. When light is directed on a given point on the semiconductor body, the photocurrent at that point increases. The change in photocurrent at points along the semiconductor body are scanned by an applied ramp voltage. In this system, a scanistor 7 is included which is responsive to light passing through the holes of a punched card, not shown.

With reference to the diagram, the start signal is received from the IBM Type 026 program drum star wheel contact. Driver 1 sets all triggers in the shift register 2 to 0, except for the first position in which is placed a 1. Driver 3 senses a 0 in the thirteenth position of shift register 2 and then permits clock pulses from clock 4 to shift register 2 and pass through trigger 5. Trigger 5 starts the ramp in ramp generator 6 anew on each clock pulse for scanning purposes. The combination of register 2 being conditioned and scanistor pulse being present from scanistor 7 yields an output from register 2 to punch magnet driver 8 when there is a hole in the card. When register 2 reaches position thirteen, the ramp is stopped, the punch magnet circuit is closed, punching occurs followed by a space and the operation is repeated.

Included but not shown are provisions for blank columns where the normal IBM 026 spacin...