Method of printing and detecting optimum bar code test patterns
First Claim
1. A method of recording information on a print-receiving medium in a bar code in which the distance between the edges of separated marks defines the meaning of said code comprising the steps of(1) printing a plurality of test patterns having groups of marks in said code of predetermined significance, each of said groups having edges of marks separated by different corresponding distances defining different densities of printed codes,(2) subsequently sensing said test patterns with a machine-controlled sensing apparatus and determining the apparent significance of said groups,(3) comparing said apparent significance of each said test pattern with the predetermined significance of that test pattern, and(4) printing subsequent data on said medium in said code with separation of marks at a distance between edges corresponding to the density of a said test pattern in which said apparent significance corresponds to its predetermined significance.
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Accused Products
Abstract
Test patterns (6) in bar code of different densities are printed at the start of document (20) preparation on the line with a alignment mark (5). The test patterns (6) are immediately read at different timing intervals (59) corresponding to the densities of the patterns. The highest density pattern (6) having test data which is recognized by the logic (61) as correctly sensed, defines the subsequent printing density to be used. First, the next line of data 3 is printed in the lowest density with a code defining the density of the subsequent printing. When a document (20) is read, the first line is read with the clock (59) intervals corresponding to the lowest density. The frequency is then changed to that defined by the code in the first line. Alternatively, the frequency is adjusted lower when an ordinary line of data is re-read and found to read incorrectly.
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Citations
16 Claims
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1. A method of recording information on a print-receiving medium in a bar code in which the distance between the edges of separated marks defines the meaning of said code comprising the steps of
(1) printing a plurality of test patterns having groups of marks in said code of predetermined significance, each of said groups having edges of marks separated by different corresponding distances defining different densities of printed codes, (2) subsequently sensing said test patterns with a machine-controlled sensing apparatus and determining the apparent significance of said groups, (3) comparing said apparent significance of each said test pattern with the predetermined significance of that test pattern, and (4) printing subsequent data on said medium in said code with separation of marks at a distance between edges corresponding to the density of a said test pattern in which said apparent significance corresponds to its predetermined significance.
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6. A method of reading information recorded in a bar code in which the distance between the edges of separated marks defines the meaning of said code comprising the steps of
(1) reading a predetermined part of said bar code with a machine-controlled sensing apparatus adapted to sense at a predetermined frequency of regular intervals, (2) comparing the results of said reading of said predetermined part against predetermined data defining density, and (3) setting the frequency of said intervals in accordance with the density defined by said comparing.
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8. A method of recording information on a print-receiving medium in a bar code in which the distance between the edges of separated marks defines the meaning of said code comprising the steps of
(1) reading a predetermined part of said bar code with a machine-controlled sensing apparatus adapted to sense at a predetermined frequency of regular intervals, (2) comparing the results of said reading of said predetermined part against predetermined data information defining the correct data-content of said predetermined part, (3) printing subsequent data in said code at a density corresponding to said predetermined frequency when said comparing establishes that substantially correct data was read by said reading, and (4) printing subsequent data in said code at a lower density than said density corresponding to said predetermined frequency when said comparing does not establish that substantially correct data was read by said reading.
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12. The method as in claim 12 in which said test patterns are three in number, each having marks defining different densities from the densities defined by the others.
Specification