US 4,068,227 AGranted

Control means for an optical bar code serial printer

AssigneeNCR Corporation

InventorRichard E. Graham

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Abstract

Control logic circuitry for a printing apparatus which records data according to a predetermined color bar code on a moving record medium. The apparatus includes first and second recording stations and a feed mechanism for successively feeding the record medium thereto in equal increments, so as to provide equally-spaced recording locations on the record medium. First and second indicia (parallel bars printed in first and second colors) are recorded on the record medium at the appropriate recording locations in conformity with the code. The surface of the record medium is used for a third indicium, which likewise is recorded thereon in the form of a parallel bar. Data to be recorded on the record medium is entered through a keyboard and converted by the logic into a bar code which is fed to logic circuitry which controls printing apparatus at the first and second recording stations and the record medium feed mechanism, thereby determining the color printed on the recording medium. The code used is of the transition type, which utilizes three different indicia. Each succeeding indicium printed on the record medium is always different from the adjacent indicium, thus eliminating the need for a separate clocking pulse on the record medium.

A code converting logic circuit for converting a binary signal manifesting a series of logic "1" and logic "0" bits to a transition code manifested by at least two signals having at least three different coding arrangements, a given order of said coding arrangements being defined, transitions from one coding arrangement to another coding arrangement in said defined order representing a logic "1" bit and transitions from one coding arrangement to another coding arrangement in an order opposite to said defined order representing a logic "0" bit, said code converting logic circuit comprising:

gating means for providing first and second output signals in response to said binary signal;
first bistable means having a first input terminal and set and reset output terminals, said first input terminal being coupled to said gating means whereby said first bistable means is capable of being changed from a set to a reset state in response to said first output signal;
and
second bistable means having a first input terminal and set and reset output terminals, said first input terminal being coupled to said gating means whereby said second bistable means is capable of being changed from a set state to a reset state in response to said second output signal;
said set and reset output terminals of said first and second bistable means being coupled to input terminals of said gating means whereby said first output signal occurs when said binary signal manifests a logic "1" bit and both of said first and second bistable means are in said reset state, said first output signal occurs when said binary signal manifests a logic "0" bit and said second bistable means is in said set state, said second output signal occurs when said binary signal manifests a logic "0" bit and said first and second bistable means are in said reset state, and said second output signal occurs when said binary signal manifests a logic "0" bit and said first bistable means is in said set state.

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Abstract

Claims6