What is thermal label printing?

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What’s a thermal transfer printer?

A thermal transfer printer is a type of printer that creates labels and signs by melting wax or resin-based “ink” onto paper, tape (made of nylon, polyester or vinyl), and even materials like heat shrink tubing. Thermal transfers printers are known for their smear-proof images and resistance to fading and are particularly well suited for creating barcodes.

How do thermal transfer printers work?

The main functional component of a thermal transfer printer is its printhead, which spans the width of whatever tape or printing medium the printer is built to handle. The thermal printhead is made up of tiny heating pins, each of which represents a single pixel (pixel size and density differ by the printer – many handheld models range between 203 and 300 dpi, or dots per inch).

The key material used in thermal transfer printing is wax or resin-based ink, which is loaded into the printer in the form of a ribbon: in a solid state, applied in a very thin layer to a backing of polyester film. This “ink” ribbon is drawn through the printer between the printing medium (paper or tape, as discussed earlier) and the printhead.

The printhead is controlled by a microprocessor, which determines which heating pins need to be activated in order to form a specific image. From there, signals are sent to the selected pins, causing them to rapidly heat and cool against the ink ribbon, melting and transferring ink off of its backing film and onto the blank label surface.

What is the difference between wax-based and resin-based thermal ink ribbons?

The final results might not differ much to the eye, but the truth is that all thermal transfer inks are not created equal. Always be well aware of the demands of your particular application before you choose which type of transfer ribbon to use.

Because of their distinctly different characteristics, wax and resin generally can’t be interchanged, but in some cases, they’re actually combined into a wax-resin hybrid ink. Below, read a little more about the traits of – and best uses for – the 3 main types of thermal transfer inks.

Wax:

Wax thermal transfer ribbons are most commonly used for printing onto paper labels. The images they produce can last for years, but not without protection: wax-printed labels need to stay dry, and are highly sensitive to abrasives, chemicals, and oils, which can wear or melt wax inks away.

Wax-Resin:

Wax-resin compounds work well with smooth – as well as coated -paper labels. The wax-resin combination produces a more refined image, and while it still needs to be guarded against excessive moisture, it offers much more durability than plain wax.

Pure Resin:

Out of the three, the pure resin is the toughest stuff you can print a thermal transfer label from, but it isn’t designed for use with paper. Resin-based thermal inks are engineered to fuse onto vinyl, polyester and polypropylene labels, and are incredibly durable. Plastic label/resin ribbon combinations are made to weather the harshest environments: they won’t fade in sunlight, can be immersed in water, and – depending on the material – can be resistant to damage from oils and chemicals. The resin is the “ink” of choice for marine, automotive, aircraft, industrial, and hazardous chemical applications.

What are the benefits of a thermal transfer printer?

Durable and Fade-Proof:

When you hold them up against traditional ink-on-paper and direct thermal labels, thermal transfer labels – especially the resin ribbon/plastic tape combinations – can’t be beaten for durability and fade resistance. While regular ink bleeds easily, and direct thermal media can darken and become unreadable in the presence of sunlight and heat sources, thermal transfer images offer far greater stability in the face of destructive elements.

Superior Barcodes:

If you’re going to invest time and money into bar-coding your business, you want to be confident that – in the end – the barcodes will actually be readable. Because they’re able to cleanly and precisely print exact bar widths, thermal transfer printers produce the most accurate and easily scan-able barcodes.

PC Compatible:

Many thermal transfer printers on the market are PC-compatible, allowing you to quickly import images and text from your computer to the label printer.

Many Print Media Choices:

With thermal transfer printers, your choice of print media isn’t limited to plain old paper. Thermal transfer manufacturers offer an impressive variety of materials to print on, ranging from reflective and tamper-resistant tapes to self-laminating labels and heat shrink tubing. For best digital offset printing Vaughan service, contact us today.

Thermal Transfer vs. Direct Thermal

Direct thermal label printing has traditionally been a niche technology used across several narrow vertical markets including meat, poultry, and dairy. However, developments in thermal paper technology have resulted in a broader range of products that are now suitable for use in many applications across nearly any vertical market. The result has been increased interest in direct thermal as the technology choice for new or upgraded applications.

What’s the difference between direct thermal printing and thermal transfer printing?

In simplest terms, thermal transfer printing utilizes a thermal ribbon and direct thermal printing does not. The thermal transfer involves the thermal print head elements (dots) heating the backside of a thermal transfer ribbon to melt and transfer the compounds on the front side of the ribbon to the label material, thus creating the printed image. Direct thermal printing requires a heat sensitive label material. The print head elements come into direct contact with the heat-sensitive material where the heat from the elements causes a color change in the material to create the printed image.

1. Thermal Print Head Life & Cost

Direct thermal printing requires the print head elements be in direct contact with the label material as it is pulled across the print head. Conversely, thermal transfer printing has thermal ribbon acting as a “buffer” between the print head elements and the label material. Many thermal ribbons are designed with a back-coating that serves to increase print head life by reducing static and friction. This benefit is not possible when direct thermal printing due to the lack of ribbon. Instead, the label material is in direct and constant contact with the print head, resulting in increased wear when compared to thermal transfer printing.

Indirect thermal applications, dust and debris that may become present on labels are in direct contact with the print head. As these foreign materials are pulled across the printhead, they may burn onto the elements or physically damage the elements resulting in poor print quality and/or premature print head failure. The same foreign material can exist in thermal transfer printing applications, but the debris would be between the label and the ribbon (i.e. not in contact with the print head elements) reducing the potential for damage.

Print head life in direct thermal printing applications is significantly reduced when compared to thermal transfer printing applications. Generally speaking, a company should anticipate direct thermal print heads providing an expected lifetime of 25% – 50% of a thermal transfer print head. As an example, if a company is printing 10 million, six inch long labels per period with an expected thermal transfer print head life of 4 million inches, they would expect to replace the print head 15 times. If the same application were direct thermal, they would expect to replace the print head 30 – 60 times. Depending upon throughput volumes, the cost differential may be significant and has to be considered in any evaluation.

2. Printer Configuration & Cost

Printer configuration is one area where some cost savings will be available. Thermal transfer printers normally have the capability of printing either thermal transfer or direct thermal. If an organization is only going to print direct thermal, there are printers available that only have the direct thermal capability. These printers are generally less costly to purchase because they do not contain any of the hardware necessary for driving and controlling ribbon. Eliminating the ribbon and ribbon hardware components also results in a less complex printer with fewer parts to wear and/or break, resulting in lower service costs and less downtime over the life of the printer. Additionally, operators don’t have to be concerned with ribbon settings or adjustments, leading to improved uptime and increased efficiency. The process of changing thermal ribbon requires downtime. Even the best operator still needs several minutes to replace the used ribbon with a new roll and downtime costs money. A standard size, 450-meter roll of ribbon will provide about 2,800 six-inch labels. If running 20 products per minute, for example, calculate into the evaluation several minutes of downtime about every 2.5 hours. Doesn’t seem like much? If calculated at 20 hours per day average production, the result over one year would be 144 hours of downtime for ribbon changes.

3. Media Selection & Cost

Media choice directly impacts the cost of labels, it will also impact the life of the print head, upper-end print speed capabilities, and print quality. These are important considerations as they may impact the ongoing cost of operations. Printhead and label are in direct contact with one another during the direct thermal printing process. Therefore, the media acts as a direct abrasive as it is pulled across the print head. If the labels are too abrasive, they will prematurely wear out the print head resulting in increased replacement costs. Many believe the use of a “coated” direct thermal label is a better solution than an “un-coated” label. It may be, but don’t depend simply on the description that a direct thermal label is “coated” to mean it’s a good label. Inferior labels can be coated the same as any other label. Therefore, a “coated” label doesn’t necessarily mean it will outperform a non-coated label. There’s no getting away from the label abrading the print head, but the choice of media can make a huge difference in the frequency of printhead replacement.

Different labels will image at different temperatures resulting in varying quality of print at different printer speed and heat settings. Choose media that can image at the printer speeds necessary to meet the production line’s throughput requirements while minimizing the printer’s heat setting. At the same time, print quality must be considered. Poor print quality can lead to un-scannable barcodes resulting in supply chain inefficiency and retailer charge-backs. Reputable label converters should have considerable experience with a variety of direct thermal label materials and should be able to provide several good suggestions as a starting point for media testing. When comparing the direct costs associated with media selection, one has to compare the cost of thermal transfer labels plus thermal transfer ribbon with the cost of direct thermal media. Eliminating the use of ribbon obviously eliminates the cost associated with the ribbon. However, the higher cost of direct thermal labels over thermal transfer labels generally wipes out that savings and then some. Media costs are all over the board depending upon the actual media selected, the label size and the volumes purchased. As a general rule, direct thermal labels will cost more than thermal transfer labels plus ribbon. However, the cost differential can be as low as 5% or as high as 50% depending upon the factors cited above.

Label Life Requirements

Requirements surrounding label life get back to the heart of the difference between direct thermal labels and thermal transfer labels…direct thermal printed labels simply do not offer the same lifetime as a thermal transfer printed label. An organization must know its label life requirements before considering direct thermal labels.

If the product being labeled could be in the supply chain for an extended period of time or in extreme conditions such as direct sunlight or chemical contact, then the technology used should likely be thermal transfer. For example, building materials are often transported unprotected and stored outdoors. Not a good choice for direct thermal technology. Another consideration would be if the information on the label is extremely critical and must be readable for an indeterminate amount of time. Examples might include pharmaceutical products or hazardous materials. These items should likely utilize thermal transfer printed labels to ensure a long lifetime.

Conversely, if the product has a short life in the supply chain and is not exposed to harsh environmental conditions, then direct thermal may very well be a good choice. Examples of this type of product could include fresh meat, dairy products, and shipped parcels. Regulatory requirements for privacy of information are another area impacting the use of direct thermal media. In healthcare, patient privacy can be at risk of personal information is available on used thermal transfer ribbon. This has led to an increased use of direct thermal media for prescription labels and patient wristbands, for example.

Environmental Considerations

In today’s world waste reduction, lower carbon footprints and sustainability are increasingly part of corporate mission statements and, in some cases, used to increase competitive advantage. Thermal ribbon uses a poly-based carrier made, in part, from crude oil products. Eliminating the use of thermal transfer ribbon can therefore positively impact a company’s goal for a reduced carbon footprint. The direct thermal technology eliminates the use of thermal ribbons and therefore eliminates the waste created through its use, but it is not suitable for all application. As advances in direct thermal materials continue to expand the potential use applications, the above considerations will take on increased importance in organizations where the choice of technology exists.

The Linerless Kit Option is designed to print self-adhesive labels without backing papers. The elimination of backing paper means less consumption and less waste making it a great solution for the environmentally conscious organization.

Evaluating these criteria and their associated costs is the only way to determine the best course of action. Each organization and potentially each use application within an organization will be different and will require evaluation based on the application’s unique needs.

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