Ink-spread compensated bar code symbology and compensation methods

• US 6,834,803 B2
• Filed: 12/10/2001
• Issued: 12/28/2004
• Est. Priority Date: 12/15/2000
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Schuessler, Frederick
• Primary Examiner(s): Le, Thien M.
• Assistant Examiner(s): Labaze, Edwyn
• Application Number:
  US10/013,400
• Publication Number:
  US 20020121553A1
• Time in Patent Office: 1,114 Days
• Field of Search: 235/462.01, 235/462.02, 235/462.49, 235/462.12, 235/462.07, 235/463, 235/494, 235/472
• US Class Current: 235/462.01
• CPC Class Codes: G06K 19/06028 using bar codes

Abstract

A method for producing an ink-spread compensated variant of an existing optical code encodation scheme, wherein the existing encodation scheme has printed areas and spaces having a length in at least one dimension being a function of a given unit length for encoding information. In the method, the pattern of printed areas and spaces for a given data input is determined and a given length is added to the length of each space while the length of the printed areas remains unchanged to enlarge the overall length of the resulting code symbol in the at least one dimension.

Claims

1. An ink-spread compensated n, k bar code symbology comprising characters having k bars and k spaces of varying lengths, the length of each bar being from 1 to m modules, the length of each space being from 1+x to m+x modules, 0<

x≦

2 and wherein the overall length of each character is n+kx modules.

2. The symbology according to claim 1, wherein the n, k bar code is an 11, 3 bar code wherein the bars and spaces are from 1 to 4 modules in length.

3. The symbology according to claim 2, wherein x is 0.5 modules.

4. The symbology according to claim 2, wherein x is 1 module.

5. An uncompensated bar code symbology and related an ink-spread compensated symbology;

the uncompensated bar code symbology comprising a set of uncompensated patterns of bars and spaces, each uncompensated pattern encoding a respective value, the length of each bar and space being from 1 to m modules;

the ink-spread compensated symbology comprising a set of compensated patterns of bars and spaces, each compensated pattern encoding a respective value and corresponding to an uncompensated pattern encoding the respective value, the lengths of the bars in the compensated pattern equaling the lengths of the bars in the corresponding uncompensated pattern, the lengths of the spaces in the compensated pattern equaling the lengths of the spaces in the corresponding uncompensated pattern value plus x modules, x>

0.

6. The symbology of claim 5, wherein x≦

2.

7. The symbology of claim 5, wherein the uncompensated bar code symbology comprises a first start pattern and the compensated bar code symbology comprises a second start pattern different from the first start pattern.

8. The symbology of claim 7, wherein:

x=1.5 modules;

the first start pattern comprises a first bar two modules in length and a first space three modules in length;

the second start pattern comprises a first bar two modules in length and a first space 2.5 modules in length.

9. The symbology of claim 7, wherein:

x=2 modules;

the first start pattern comprises a first bar two modules in length and a first space three modules in length;

the second start pattern comprises a first bar two modules in length and a first space four modules in length.

10. The symbology of claim 5, wherein the uncompensated bar code symbology comprises a first stop pattern and the compensated bar code symbology comprises a second stop pattern different from the first stop pattern.

11. The symbology of claim 10, wherein:

x=1.5 modules;

the first stop pattern comprises a bar/space sequence b1-s1-b1-s1-b2-s1-b1-s1; and

the second stop pattern comprises a bar/space sequence b1-s1.5-b1-s1.5-b2-s1.5-b4-s1.5;

where “

bi”

represents a bar i modules in length and s1 represents a space i modules in length;

the first and second stop patterns each followed by a terminating bar between one to four modules in length.

12. The symbology of claim 10, wherein:

x=−

2 modules;

the first stop pattern comprises a bar/space sequence b1-s1-b1-s1-b2-s1-b1-s1; and

the second stop pattern comprises a bar/space sequence b1-s1.5-b1-s1.5-b2-s1.5-b2-s5;

where “

bi”

represents a bar i modules in length and s1 represents a space i modules in length;

the first and second stop patterns each followed by a terminating bar between one to four modules in length.

13. An uncompensated bar code symbology and related an ink-spread compensated symbology;

the uncompensated bar code symbology comprising a first set patterns of bars and spaces, the length of each bar and space in patterns in the first set being from 1 to m modules;

the compensated bar code symbology comprising a second set of patterns of bars and spaces, the length of each bar in patterns in the second set being from 1 to m modules;

the length of each space in patterns in the second set being from 1+x to m+x modules; and

where

the sum of the lengths of the bars in each respective pattern in the first set being one of an even or odd number of modules, and the sum of the lengths of the bars in each respective pattern in the second set being the other of an even or odd number of modules.

14. The symbology of claim 13, wherein the uncompensated bar code symbology comprises (11, 3) data characters of Code 128 where the sum of the lengths of the bars is an even number of modules;

and

the compensated bar code symbology comprises (11+3x,3) Code 128 data characters where the sum of the lengths of the bars is an odd number of modules.