A-61408 September 1995
C-17
Low Bar Code Ratings
The following table identifies the most common causes of the low
bar code ratings/grades:
Field
Problem Type
Cause
W/N NEW
Dimensional
Bar codes not printed according to specifications (refer to
Bar Code Specifi-
cations ).
Inaccurate measurements due to:
• Ink smearing (improper curing)
• Ink spreading (use of super-absorbent paper)
• Use of dot matrix printers (ragged edges)
CONTRAST RMIN
Reflectance Bar elements are too light. Causes:
• Use of old ink ribbon
• Print hammer pressure too light
• Defective/dirty print head
Space elements are too dark. Causes:
• Dark colored paper background
• Stain on paper
MOD
Reflectance
Bar code element edges are ragged rather than straight. Often caused by
use of a dot matrix printer.
DEFECT
Reflectance
Bar elements contain voids (white spots). Causes:
• Use of old ink ribbon
• Print hammer pressure too light
• Defective/dirty print head
Space elements contain dark spots. Causes:
• Paper which contains flecks
• Ink smearing (improper curing)
• Ink spreading (use of super-absorbent paper)
• Defective/dirty print head
• Toner contamination (if using a laser printer)