14 Oct Printer Quality Assurance and Preventive Maintenance
A consistent print quality, as well as an extended printhead life are both achieved with regular cleaning, media management, sampling and replacement of aging parts. A printer quality assurance plan should include each of these vital procedures. A well-maintained printer with scheduled cleaning and maintenance can produce several hundred thousand consistent, high-quality labels. The following steps will show how to incorporate each element into a sound quality assurance plan.
The regular cleaning of printheads protects against sudden failures and quality degradation over time. Abrasion is the major leading cause of premature printhead failure. One estimate claims abrasion is responsible for more than 80 percent of failures.
When dirt, dust and other contaminants collect on the printhead they can block heat transfer, which can cause other printhead elements to overheat and burn out. This will require replacement of the printhead. After continuous exposure to heat, the contaminants become hardened and baked onto the printhead, which can cause corrosion. Before burning out, blocked elements create print quality problems by producing voids or lighter images.
Buildup and related problems can be prevented through regular cleaning with specialty printhead cleaning products, including pens, swabs and cards. Printer cleaning products are specially formulated to lift dirt and grease from the printhead and quickly evaporate which won’t leave a buildup behind. The applicator material is specifically designed not to stick to the printhead and leave debris.
Businesses that use label printers should make printhead cleaning part of their regular operational routine. Cleaning the printhead every time the ribbon is replaced in thermal-transfer printing, or at every media change for direct thermal printing, should be satisfactory for most users. Inexpensive materials can make printhead cleaning quick and convenient. The investment made in time and materials for regular printhead cleaning is repaid many times over because of the costly printhead failure problems it prevents.
Media selection and handling are also highly manageable variables that affect quality.
When label material and ribbons are loaded correctly every time with thorough operator training and review, you will be able to prevent many wrinkling and uneven printing problems.
Purchasing managers must also be trained in regards to the impact media has on print quality and overall operational efficiency. Labels and ribbons must be matched to each other and also to the usage conditions they are required to perform in to ensure proper imaging performance. Labeling systems integrators or the printer manufacturer will recommend several acceptable options.
Users will usually be able to find lower-cost options that have not been specifically certified or recommended. Even though these options will save money initially, in the long run you will be risking print quality that could create even more expensive problems down the road. If the media you have implemented causes even one print quality problem that led to a customer chargeback, the material savings would be offset several times over by the resulting fines, returns processing expenses and lost customer confidence.
Sampling is another method to monitor and test print quality. Operators need to be trained to perform visual label inspections daily to look for uneven images, voids, light printing or other obvious signs of trouble. More rigorous quality tests and third-party sample certification, should be regularly scheduled by all companies. Qualified third parties can provide unbiased analysis and recommend necessary corrective actions.
Only relying on visual inspections is a dangerous practice that could lead to labels that look good but are not in compliance. Many print quality problems are not visible to the naked eye. Using a handheld barcode scanner to see if labels will read is also not a sufficient quality check. The successful reading of a label with a handheld scanner in a controlled environment is no indication the label will read in real-world conditions. Most cartons with compliance shipping labels are processed at distribution centers that use high-speed conveyors and material handling equipment to move materials several hundred feet per minute. These conditions expose quality problems very quickly, and usually cannot be replicated in a test environment.
Companies that have compliance labeling programs will gladly inspect and monitor supplier label samples, or have designated a third-party service to certify label quality. Suppliers should take advantage of these resources by regularly sending label samples for testing. You should also always have your labels tested and recertified after any changes are made to the printing process, including the introduction of new label printers, media, software or printing locations.
The final step in ensuring barcode label printing quality is planned replacement of the printhead. Printheads are replaceable parts and there is no need to replace the entire printer at the end of a printhead life cycle. Printheads should be considered consumables, although expensive ones, and should be replaced as necessary.
The lifespan of a thermal printer depends on the type and quality of images being printed, heat settings, media as well as other factors. Users should record the lifetime print volume of each printhead and begin monitoring quality more closely as it nears the end of it’s life. Volume can be monitored with counters or other built-in features in printers, by recording and tracking media that is loaded onto the printer or by calculating average monthly printing volume. To avoid downtime, it is a good idea to have a spare printhead ready when service or replacement is needed.
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