Digital Design EVOLUTION II - Appendix A - Producing Reliable Bar Codes; Barcode Integrity; Contract Ratio; Bar Separation

3 EVOLUTION 1 SYSTEM MANUAL Issue Issue 1.1 20 Dec 2006
APPENDIX A – PRODUCING RELIABLE BAR CODES
Printing reliable barcodes requires that several key issues be observed.
1. Barcode integrity
2. Contrast ratio
3. Bar separation
4. Quiet zone
BARCODE INTEGRITY -
Barcode integrity is the validity of the data contained in the barcode. This
includes valid characters and the correct ratio of dark to light bars.
CONTRACT RATIO -
The contrast ratio is the optical density of the print against the background
substrate. For example a black ink barcode against a white coated cardboard
versus a black ink barcode on a brown cardboard.
BAR SEPARATION -
Bar separation is the ratio of a dark bar to a light bar. This is one of the
most critical parameters to be observed. Assuming that the aspect ratio of the
printed barcode is correct, bleed factors can greatly diminish the readability of a
barcode. Bleed factors vary greatly depending on substrates. For example
printing on virgin versus recycled corrugated cases.
EVOLUTION II printers have the capability to adjust various parameters of the
printed barcode to circumvent the inherent problems in producing a reliable
printed barcode. These include:
Dark Bar width
White bar width
Even though the ratio of a dark bar to a light bar should not be changed it might
be necessary to alter the printed barcode by adjusting the light bar size relative to
a dark bar size allowing for bleed factors found on different substrates
QUIET ZONE -
These are areas at the beginning and end of a barcode symbol that allow
optical equipment to differentiate the barcode from other printed material.
The inks developed for the EVOLUTION printers will produce, at 300 dpi and
200ft/min, a class “A” barcode on brown corrugated, but care must be exercised
in programming the various parameters that control how the printed image is
produced. As with any fine resolution image the distance from the print head to
the product is of utmost importance. Trial and error is often required to produce
the desired results.