Denso BHT-700BB-CE Operator's Manual page 40

When Unable to Successfully Read Barcodes
Cause
When the illumination LED is
focused on the printed surface of
Specular the barcode from directly above,
reflection there are times when scanning is
unsuccessful
reflection.
Scanning may be unsuccessful if
the BHT reading window is too
Distance from
close to or too far from the
barcode
barcode, even when the barcode is
within the illumination LED range.
Barcode surface Scanning may be unsuccessful if
curvature the barcode surface is curved.
Barcode surface Scanning may be unsuccessful if
dirt the barcode surface is dirty.
Scanning may be unsuccessful if
Barcode reading
the barcode reading window is
window dirt
dirty.
Barcode
Direct sunlight, adversely
ambient light sunlight or the brightness of the
surrounding light.
Change the BHT scanning angle and try
again.
due to specular
Move the BHT slowly toward or away from
the barcode and try again.
The illumination LED range is only a
guideline.
Barcodes can be read at a maximum
distance of 62 cm from the BHT reading
window.
Scan the barcode at the center of the
barcode reading window.
Wipe the dirt from the barcode and try
again.
Blow any dust away with an airbrush, and
then gently wipe the reading window with a
cotton swab or similar soft object.
scanning may be Perform barcode scanning away from
affected by direct direct sunlight. Try adjusting the brightness
of the surrounding light when scanning
indoors.
26
Scanning Barcodes
Countermeasure