TECHNICAL INFORMATION, ID Bar Code, Optical Requirements
Sysmex SF-3000 Operator's Manual -- Revised September 1995 C-19
(2) Reflective characteristics of the label surface
The bar code reader defines the white and black by the reflected light intensity when the
light is applied to the label at an angle of approximately 25°. Therefore, most of the
reflection of the label surface should be diffused reflection. For example, a laminated
label may cause specular reflection, which will increase the reflection directivity too much
and cause the ID reader to miss scan lines. See the following figures.
Figure C-4: Specular Reflection Figure C-5: Diffused Reflection
(3) Irregularity and roughness of the printing
When a bar element is magnified, the following may be observed. The variation
coefficient (S) in the width of a bar should be less than or equal to 20%.
S(%) =
Max-Min
Max
x 100
Max
Min
Bar
Figure C-6: Magnified Bar
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