When it comes to satisfying retailer requirements and preventing chargebacks, many of the changes that need to be made must be researched. Implementation can be costly and complex. You might have to wait for information from the retailer before you can do anything.
However, preventing chargebacks caused by barcode labels that can't be scanned is a different story. Producing quality GS1-128 labels and having a process for identifying and addressing potential problems aren't difficult, expensive or complicated. Merchandise suppliers just need to be proactive and take the time to put a process in place at their own distribution centers in order to avoid issues at retailers' distribution centers.
In this article, we'll discuss two kinds of thermal printing methods, common labeling problems, the importance of using a high-quality barcode verifier, and the implementation of processes that ensure your labels are legible and scannable.
Thermal Transfer Printing vs. Direct Thermal Printing
Thermal printing is recommended for barcode printing because it uses thermal printheads to produce accurate images with well-defined edges. There are two types of thermal printing – thermal transfer and direct thermal.
With thermal transfer printing, a ribbon is heated by the thermal print head and ink is melted and absorbed into the label. The ink actually becomes part of the label. With direct thermal printing, a heat-sensitive, chemically-treated label is passed under the thermal print head, and a barcode is created when heat causes the label to darken.
Thermal transfer can use a wider range of label materials than direct thermal printing. Thermal transfer barcodes tend to last longer because the labels aren't affected by heat and light, which is important if your barcodes spend a lot of time in transit or in a warehouse. There are three types of ribbon used in thermal transfer, and the right ribbon must be matched with the right ink and label. These variables increase the risk of creases, smudging and poor image quality.
Direct thermal printing doesn't use ribbon, ink and toner, so you don't have to worry about compatibility issues, related costs, or smudging. However, premium-coated facestock, the label material used with direct thermal printing, tends to be more expensive than thermal transfer. Because direct thermal label materials remain chemically active after printing, exposure to heat and light can cause the label to darken.
For these reasons, direct thermal is not recommended for "lifetime" printing applications. However, if you have control over the environments where cartons are stored and transported, as well as the time spent in these environments, direct thermal is more desirable because of the smudge-resistance factor. Thermal transfer labels last longer, but a direct thermal label will usually remain scalable for at least six months.
Common Labeling Problems
Most of the problems that would prevent a label from scanning properly are clearly visible to the naked eye. Here are some of the most common issues we see.
The bars are too light (underburn). This can happen when the pressure applied from the printhead to the label material is uneven or inadequate. With thermal transfer printing, the heat may be too low.
The bars are too thick (overburn), which is typically caused by too much heat.
The barcode is smudged. Smudging can be caused by using the wrong combination of ribbon, label and ink, as well as exposure to heat. Labels can also smudge if cartons are loaded in a way that allows barcode labels touch. Again, smudging doesn't happen with direct thermal heating.
Diagonal lines or white streaks appear within the barcode. This usually happens when the ribbon isn't loaded properly or feeding correctly.
There are spots or voids within the barcode. This can be caused by the printhead burning out elements or abrasions, a wrinkled ribbon, or the use of incorrect label stock.
Other common issues with barcode labels include an unsustainable wide/narrow ratio and poor edge definition. Poor edge definition is often caused by fast print speed, incompatible label stock and print method, and printing in vertical orientation.
Verification of Barcode Print Quality
Merchandise suppliers must identify and address barcode quality issues as quickly as possible to avoid delays and chargebacks at retailer distribution centers. Sample labels should be printed from every printer in use, and a high-quality, ANSI/ISO barcode verifier should be used to determine the quality of barcodes and whether they're scanning at the proper grade.
Barcode verifiers do more than ensure a barcode can be scanned. Barcode verifiers ensure a barcode can be scanned in multiple environments at fast conveyor speeds. They can measure a variety of data that isn't visible to the naked eye, including barcode language (symbology), encoded data, data check digit and symbology check digit, bar and space dimensions and tolerances, allowable ratio of wide to narrow dimensions, and reflectance parameters.
Most retailers require an ANSI Grade of B or higher for GS1-128 barcode labels. If one or more retailers require a grade of A, it's a good idea to verify that all barcodes meet that standard so barcodes scan properly at all retailer facilities.
Verification of barcode quality should be done at least once per day, and ideally once per shift. If you're about to prepare a large order for shipment, it's a good idea to verify barcode quality before you get started. This will allow you to detect and fix printing issues before you end up slapping a large run of labels onto cartons and having them fail at the retailer's distribution center.
We encourage merchandise suppliers that do not have a barcode quality verification program in place to use this information as a roadmap. Have your cross-functional team meet with upper management to explain how such a program is a relatively easy fix and can reduce chargebacks that are completely avoidable. Packers who put labels on cartons need to be aware of their role in this process and the benefits it will create. There should also be some kind of identifier on labels that allows you to trace each label back to the source printer so issues can handled quickly and efficiently.
Merchandise suppliers, we want your feedback. What print method do you use and why? How is it working? Do you have a barcode quality verification program? How is it working? What problems are you facing, and what steps are you taking to overcome them? Please share your stories on the RVCF forum boards, join the discussion, and help and learn from other members.
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