Making the Mark: Selecting the right ink for your application

Created by Lin Zhu, Director of Ink Development | | Quality controll | Videojet Technologies | Wood Dale, IL

A trusted partner can be the difference for ever-evolving industries in these rapidly progressing times. Forged on a foundation of communication, such relationships can yield mutually beneficial results for both business firm and client. Take packaging professionals: aligning with the right coding and marking supplier can help navigate the crucial ink-selection process. With so many inks to choose from and so many factors to consider when using ink jet coding equipment, finding the right ink is of the utmost importance to providing peace of mind and helping save money.

The best ink developers and suppliers study the evolution of packaging materials, understand the range of manufacturing environments, and then rigorously apply chemical technologies to develop inks that ensure long-lasting code integrity and performance. Those experts can create inks to accommodate a variety of performance requirements.  Code appearance is often an important ink attribute. For example, invisible UV fluorescing inks may be used when manufacturers want to print an invisible code also known as a ‘covert code’. This normally invisible code enables package manufacturers to discretely track their package quality through its supply chain should a question ever arise over package integrity.  At the same time, these discrete codes protect the integrity of their customer’s premier visual packaging brand elements. In another application, invisible codes applied by a manufacturer enable discrete tracking through the products intended distribution chain. This can be a particularly useful approach to thwarting diversion, the sale of authentic high-value products outside legitimate distribution channels. Because the fluorescent ink is only visible with a UV light, codes will remain invisible to consumer or potential diverter. 

The material being coded influences ink performance. Colored plastics bottles and containers of all sizes and shapes are favored in the cosmetics industry as they help brands stand out in crowded displays where they are competing for valuable shelf space.  New high-performance plastics are constantly being developed. According to the Euromonitor packaging database, over 80% of global personal and home care bottles, jars and containers are made from high-density polyethylene (HDPE) and polyethylene terephthalate (PET).  Such packaging can present coding challenges because of the wide variety of “slick” surfaces and formulations that can make ink code adhesion difficult.   Also, the end use should be considered, as personal and home care products contain solvents which may adversely affect ink adhesion. Robust plastic inks have been designed to be used on slick surfaces to provide optimal adhesion and coding durability for a match with cosmetics bottles.

Environmentally “green” is becoming more important. Leading ink suppliers have the expertise in chemical regulations and have invested heavily to develop more environmentally friendly solutions that can best meet the cosmetics industry needs.

The production environment also plays a significant role in how inks adhere. Factors like moisture, temperature, and humidity can all impact initial ink code adhesion and durability. Drying and curing times afforded by product processes and manufacturing environments must be accommodated. Understanding these fixed constraints are crucial to selecting an ink that can survive this initial phase of the products life cycle. Also, the time between printing the code and its first contact with a material handling component, like a belt or guide rail, or even another product places stipulations on ink performance, all of which may influence the code’s adhesion and legibility. These manufacturing process conditions can result in ink transfer or code smudging, and therefore should be considered when selecting the required ink.

Identify What You Need

Printing equipment suppliers focus heavily on new product design to provide the packaging industry with innovative, class leading coding solutions that support stringent production needs. However, research and development investment should not stop at the coding equipment. The demand for new specialty inks suited to an increasing variety of innovative packaging is both a sign of real customer challenges and an indicator of where hardware suppliers should direct investment and expertise.

In preparation for discussing ink selection with the experts, you should ask yourself the following questions:

  • What material am I coding onto?
  • Are there any surface coatings or contaminants from the manufacturing process present on the product either before or after coding?
  • What product surface color variation exists, and what is my or my customer’s requirement for visual or machine readable code contrast?
  • What is the printer operating environment and what temperature extremes will the product itself experience and the code need to endure?
  • When and what components come into contact with the ink code after printing that may impact ink dry time and durability?

Access Experts

Manufacturers should take full advantage of the ink expertise offered by their marking and coding ink and equipment partner. There are multiple options and considerations to take into account when choosing ink, but by engaging hardware application specialists and ink chemists together, you can achieve a better fit to your exact needs. Ink specialists, such as Videojet, can narrow the selection from over 100+ possibilities to as few as one or two potential inks which can then be more closely scrutinized in the final ink selection process. Ink suppliers can also help troubleshoot new problems that may arise years after initial implementation, should packaging design elements or the production process change.

For example: An ink that worked yesterday might not work today due to a subtle change when upgrading your manufacturing line or an undisclosed change to the substrate by your supplier. An ink specialist and their unique set of tools can help diagnose these problems and recommend solutions that get code performance back to an optimal state.

Keeping up with New Technology

Just as manufacturers are always improving their processes, ink specialists are constantly researching new formulations to meet new coding application challenges. Manufacturers need to take this into consideration as they upgrade or expand their systems.

However, resist the temptation to cut corners. Some packaging teams may move to save money by purchasing fluids from a third-party ink supplier. Since these fluids are engineered without taking into consideration the printer specifications, these fluids can degrade a printer’s performance and code appearance over time. As a result, off-brand supplies can end up costing much more in the long run due to costs associated with excessive maintenance, premature part failures, and unpredictable downtime.

Bottom Line

Packaging professionals will be well-served by partnering with a thorough coding and marking supplier in order to choose the proper ink for their applications. This relationship can be the critical difference in any business climate. 

About the Author:

Lin Zhu is Director of Ink Development at Videojet Technologies. Lin joined Videojet in 1994 as Research Chemist and progressed through various technical roles. Lin was named Director of Ink Development in 2007.  Prior to joining Videojet, Lin did basic chemistry research at the University of Chicago.  Lin has a BS in Chemical Engineering from Tsinghua University in China and a PhD in polymer material science from the University of Akron.





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