Socket CF RFID Reader Card 6E, Руководство пользователя

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56 | APPENDIX C: BARCODE LABEL SPECIFICATIONS
Appendix C
Barcode Label Specifications
All barcode symbols/labels should satisfy the appropriate AIM Uniform Symbology
Specification.
Background Substrate:
The barcode symbol should be printed on material (media) that is reflective and has a
matte (not glossy) finish. A background diffuse reflectance of at least 70% to 80% is
desirable for optimum contrast. Retro-reflective media should be used to obtain decode
distances greater than 36 inches.
Ink Color and Type:
The inked bars should not exceed 25% reflectance at the wavelength that is being used
for reading, whether printed with black ink or colored ink. The reflectance value should
not vary more than 5% within the same character.
Voids and Specks:
The code should be printed clearly, free of voids, specks, blemishes and lines that could
“fool” the scanner. Specks or blemishes in the white spaces, or false or missing bar
sections could be interpreted by the reading equipment as part of the code. Generally,
the width of such flaws is more serious than the height. Code symbols/ labels should be
rejected if these defects are present.
Definition:
The bars in the barcode symbol should be well defined. Their edges should not be rough
or fuzzy, so that the bars and spaces have the proper widths intended for the barcode
symbology used.
Contrast:
Background reflectance (that of the substrate on which the codes are printed) should
always provide a good contrast relative to the ink reflectance (that of the code bars). The
difference between the two should be at least 37.5% at the wavelength used for reading.
Tolerance:
The ratio of the widths of bars and spaces in a barcode symbol must conform to the
appropriate AIM barcode specifications and can cause problems if not correct throughout
the barcode. Problems can occur when bar edges are smeared or rough, or when they
exhibit voids.