Everything You Need To Know About Thermal Printing
Early in the morning on the 26th of June back in 1974, a man by the name of Clyde Dawson stopped into a Marsh’s supermarket in Troy, Ohio to pick up a 10-pack of Wrigley’s Juicy Fruit gum. Sharon Buchanan, the cashier that morning took Clyde’s order. But rather than recording that transaction by hand, she simply scanned the barcode — the first barcode, that is.
Personally, that sounds a lot nicer than writing down every. Single. Transaction. All day. Everyday.
Since its introduction in the early 1970s, the barcode has taken off, becoming a necessity for most industries. It has become the industry standard for cutting costs, saving time, and accurately recording and storing information.
In the information age that we live in, smart businesses rely on data to drive key insights and decisions in their operations. Companies practically build their decisions on the information gathered by this data — so it better be trustworthy! Otherwise, their decision making could be flawed and/or compromised.
Automating data collection and eliminating human error is the key to ensuring data accuracy. For many companies, the barcode is a trusted and reliable vehicle for acquiring this information.
This system of barcode automation has found its way into thousands of industries and applications. The simple black-line pattern on every label tracks everything from a bag of potato chips to patients at a hospital. All it takes to unlock the information inside of the barcode is a simple swipe of a scanner.
Scanning a barcode is fast, reliable, and largely reduces human error. Sounds a lot better than entering data by hand, right?
Overall, barcodes are a cheap and affordable mechanism used to track products, equipment, and people.
Variations of the barcode have been fabricated over the past 45 years to accommodate varying company needs. They can be printed on paper, plastic, or something in-between.
However, with all this being said: The barcode is only as reliable as the application that it is printed onto.
If the label falls off or the ink smudges, your barcode is completely useless. For this reason, it is extremely important that the right label is chosen for each application and environment.
There are tons of factors to consider when determining exactly which label is right for business. It can be overwhelming, we know — but that is exactly what we’re here for!
We want to make this process as easy and painless as possible for you. By the end of this article, you will know everything there is to know about thermal barcode and shipping labels.
Chapter 1: The Basics
The first and easiest question to answer is: What is your barcode going to be responsible for tracking? While paper labels are the most popular and cost-effective, they are not necessarily the best option for every situation.
Here are the most popular media types:
Labels are the most popular and cost-effective media for barcodes. This is primarily because they are easy to design, print, and attach. The anatomy of a label is comprised of facestock, adhesive, and a liner.
The facestock is simply the paper that your barcode is printed on. Label adhesive is the sticky material that bonds the label to its application. Finally, the liner is what protects the adhesive prior to it being applied. In other words, it is the material — typically wax or polyester — that the label is attached to before being used.
They are packaged either in rolls, sheets, or fanfolded and can be used for inventory tracking, shipping & handling, cross-docking, warehouse management systems, etc …
Tags are another popular barcode media. They are typically thicker than a label and don’t have any adhesive. Because of their lack of adhesive, tags are usually applied with a plastic string or staple. A tag is good for application to a medium that doesn’t have a smooth surface that a paper label would need to adhere too.
The most common application of a barcode tag is in the apparel industry. Vendors selling clothing don’t want sticky adhesive residue left behind on the garments they are selling.
Wristbands are the least common media for barcodes, but nevertheless, are extremely important. Their needs are quite specialized, making them a more niche market.
For the most part, wristbands are used to keep track of animals or people. They are preferred in these situations, as the likelihood of them falling off is much lower than for a label or tag.
There are several different printing technologies that you could utilize to print your barcodes. However, one method — thermal printing — is by far the most widespread.
“Why?” you ask? The reasons for this are quite simple: thermal printing is easy, fast, and efficient.
Thermal printing comes in two varieties: direct thermal and thermal transfer. While most thermal printers will print in both thermal transfer and direct thermal, the advantages and disadvantages of each medium are important to your selection.
Thermal transfer (TT) technology uses a heat-sensitive carbon ribbon. The ribbon is melted onto the label as it passes over the thermal print head to present the image or text. The ribbon used for your label will depend on your media type, printer, and application. See Chapter 5 for additional information on choosing the right ribbon for you.
These thermal transfer labels are more durable than their counterparts (direct thermal), making them less likely to scratch or fade and more likely to last a long time.
If your company requires long term storage or your labels are likely to be exposed to direct sunlight, a thermal transfer label is for you.
Direct thermal (DT) does not require any ink or ribbon to print. Instead, there is a heat sensitive layer on the paper that changes color as it is exposed to the printer’s print head. The print head rapidly heats and cools as the paper passes through it.
DT labels are great for temporary uses such as shipping labels, carton packaging that is going to get tossed away, and inventory with a high turnover rate.
The labels only need to withstand a couple of weeks of use and do not require a ribbon. Direct thermal produces high quality, easy to scan labels, but without the extra cost of a required ribbon.
While operating without ribbons or ink may sound like a nice option, there are some downsides to DT printing…
Since the paper is constructed to be heat sensitive, it cannot be exposed to extreme heat or sunlight for too long, or the label could be damaged or faded.
Therefore, these labels do not last as long as the alternative — thermal transfer.
Chapter 2: Why Barcodes?
So what’s the point of using barcodes? They make inventory management so much easier! Barcodes can be used for a variety of purposes to help make your company more efficient. Here are a few ways they help you out:
Inventory Tracking and Management
Shipping and Transportation
Each character in a barcode is expressed as a combination of wide and narrow black bars — that’s the obvious part that we already know. These bars that seem so simple can hold tons and tons of information that is decoded once scanned onto a computer. What you probably haven’t noticed is that there are in fact many different types of barcodes. The differences are so minute that they’re easy to miss. The variations are as followed:
This type of barcode includes the Universal Product Codes (UPC) and is commonly used for retail applications, but can also be used in blood banks and even some old libraries. These are handy because they usually offer self-checking, error correction features. This type of barcode can only be found in the US and Canada.
This is a worldwide barcode label that is all-purpose, but specifically tracking and data collection in shipping. These tend to be used in the healthcare industry because of their ability to hold large amounts of information with error reduction.
Many industries have barcode systems specific to what they do.
One-Dimensional (1D) Barcode Types
UPC Code – These are used to label and scan consumer goods at point-of-sale around the world, but mostly in the US. the first and more common variation is UPC-A, which encodes 12 numerical digits. Meanwhile, UPC-E, a smaller variation, encodes only 6 digits.
EAN Code – These are similar to UPC, but are used primarily in Europe. They are used for a geographical application. The EAN-13 has 13 digits and is the default form factor. EAN-8, on the other hand, barcodes on products where only limited space is available, like small candies, for example.
Code 39 – You may see these referred to Code 3 of 9 as well. They are used across many industries, especially the automotive industry and the US Department of defense. What makes this one different is that it uses both numerical digits and characters. The name comes from the fact that it can only encode 39 characters (even though it has not upgraded to 43).
Code 128 – This one is similar to Code 39, but is much more compact. These high-density codes are used in logistics and transportation industries for ordering and distribution — not so much POS. Code 128 barcodes are useful in supply chain applications because they can store diversified information and support any character of the ASCII 128 character set.
ITF – AKA Interleaved 2 of 5. These are used to label packaging materials all around the world. They are capable of handling high printing demands, especially when printing on corrugated cardboard. ITF barcodes encode 14 numeric digits and use the full ASCII set.
Code 39 – These barcodes are used in logistics to identify packages in retail inventory, label electronic components, and also provide supplementary delivery information for the Canadian Post. It is similar to the Code 39 barcode in that it comes with full ASCII support, but it is an improved version. The barcode itself enables additional security and its compact size makes it much shorter.
Codabar – This one is used by logistics and healthcare professionals, like the U.S. blood banks, FedEx, photo labs, and libraries. It is super easy to print and can be produced by any impact style printer (that includes typewriters for those of you who still have one of those!). No computer is necessary! Codabar barcodes are discrete, self-checking, and able to encode up to 16 different characters with an additional 4 start/stop characters.
GS1 Databar – Also called the Reduced Space Symbology, this standard barcode type is used for retail coupons in the US. They are used to identify consumer coupons, produce, perishables, and even some things in the healthcare industry.
MSI Plessy – You can find these barcode labels on the shelves at the supermarket. They are used for inventory management in retail environments.
Two-Dimensional (2D) Barcode Types
QR Code – This is a consumer-focused barcode. These barcodes are used for tracking and marketing purposes, such as advertisements, magazines, and business cards. Not only are they free to use, but they are also flexible in size, have a high fault tolerance, and have a quick readability. Their only downside is that they cannot be read with a laser scanner. The four modes of data supported by QR codes are numeric, alphanumeric, byte/binary, and Kanji.
Datamatrix Code – usually label smaller items, goods, and documents. They are also ideal for labeling small electronic components.
PDF 417 – As you might be able to tell by the name, the PDF417 is great for storing photographs, fingerprints, signatures, text, numbers, graphics, and anything else that requires the storage of huge amounts of data. And by “huge amounts” I mean, 1.1 kilobytes of machine-readable data.
Aztek – If you’re in the transportation industry, this barcode is for you. They are used for tickets and airline boarding passes. These labels are so strong that they can still be decoded even if they have a bad resolution, making them useful both when tickets are printed poorly or presented on a phone. This makes the boarding process at an airport much quicker and smoother.
To summarize: if you need to decide on which format to use, ask yourself these questions:
Do you want your product scanned at the point of sale in retail stores?
You want: UPC or EAN
What kind of characters need to be supported? Alphanumeric?
You want: CODE39, CODE128, or QR CODE
Do you have less space available on the package?
You want: EAN8, UPC-E, CODE128, or DATAMATRIX
Which material will you be printing the barcode one? Cardboard?
You want: ITF
Do you need to store a lot of data on the barcode?
You want: PDF417
Chapter 3: Let’s Talk About You & Your Specific Needs
How Long Do You Need the Barcode / Label to Last?
- Less Than 6 Months – As stated earlier, direct thermal labels are more heat sensitive and therefore do not last as long.
- 6 Months Or Longer – Thermal transfer is the sturdier of the two options. If you plan to store the labels for over 6 months, TT should be your choice.
In What Environments Will the Label be Exposed?
- Indoors – Choose Direct Thermal! DT labels will only be able to last about 1 month outdoors exposed to light before it begins to fade. The heat sensitivity of these labels puts a time restriction on the label’s lifespan.
- Indoors or Outdoors – Thermal transfer labels are more suited for outdoor use than direct thermal. However, if you are using a paper label, then it still won’t last very long. Alternatively, if you are using a polypropylene label it will be much more suited to deal with the elements.
What Kind of Printer Do I Need?
Well for starters, you will need a thermal label printer. Inkjet and laser printers are not quick, efficient, or cost-effective for printing barcode and shipping labels. There are 3 types of thermal label printers: industrial, desktop, and mobile. Some well-known thermal printer brands that might ring a bell are Zebra, Datamax-O’neil, Sato, Intermec, Printronix, Dymo, and many more.
These printers can print anywhere from 3,000-10,000 labels per day. They are designed to withstand high volume printing, which is why they are typically kept in warehouse and manufacturing environments where high-quantity and high-quality printing is a must.
This is the printer you want to use if you plan on printing around 500-1000 labels per day. They are about the size of a toaster and are typically used for retail applications, asset tracking, and small-scale labeling operations that require lower print volumes.
They are not as compact as the mobile printers but they are small enough to fit on any desk. Though they are smaller than industrial printers, they print with equal quality and speed.
Mobile printers are the perfect solution for low-quantity printing on the go. They are super compact printers that can latch onto your belt, so you can create high quality labels in any environment, indoor or out.
Chapter 4: Choosing the Right Label For You
The majority of labels you will come across will typically be made from the same 3 materials: Paper, Polypropylene, or Polyester. For most people, a disposable paper label will work just fine. However, some applications and environments require a material that is a little more durable and weather resistant. For a breakdown of the three most popular label materials, see below.
The overwhelming majority of people that print barcodes and labels use paper labels. The reason is quite simple, they are significantly cheaper than their poly counterparts. Due to the consumable disposable nature of most labels, paper is almost always the way to go.
- Cheapest Option
- Easy to use
- Good for everyday, ordinary applications
- Not waterproof
- Almost anything other than outdoor use or chemical exposure
For those individuals looking for a long lasting label, polypropylene is a good bet. Just like paper, there are both direct thermal and thermal transfer polypropylene labels. However, one thing to be aware of with direct thermal polypropylene labels is that they are slightly gray in nature. That is because there is no leuco die present in the label.
- Suited for rugged application
- Moisture-resistant, Tearproof & Smudgeproof
- Long print life
- Tree-free and environmentally friendly
- Resistant to oil, grease, and other chemicals
- Much more expensive than paper, but cheaper than polyester
- Requires wax/resin ribbon
- Frequently handled documents
- Long term shelf and bin labels
- Medical or chemical labs
- Outdoor applications
The vast majority of media is going to be blank/white but a variety of colors are available. When a label or tag is colored it is referred to as “floodcoated.” This just means that the entire surface is colored without any edge or border. They are great for color coding inventory by time, lot numbers, or types of products.
Commons colors are yellow, light green, light blue, and orange. If you are barcoding with these labels, it would be better to pick a lighter color to help with readability and scannability.
When choosing your label, make sure to choose an adhesive that will stand up to the tasks your label will perform. The 3 questions you need to answer to figure this out are:
1) How long does your label need to remain adhered to the surface?
Permanent adhesives are exactly what they sound like … permanent. Once applied, they will be difficult to remove. This is great for stock labeling or shipping and handling. You don’t want to worry about your shipments getting lost because a label fell off.
The second type of adhesive is removable. These labels can be removed without being damaged or leaving residue on the surface. Removable adhesive labels are easily repositionable and useful when you want to update what is written on the label.
2) What is the texture of the surface on which the label will be applied?
Labels tend to stick more effectively to clean, smooth surfaces. Rough and uneven surfaces require more aggressive adhesive in order to adhere. Additionally, will your surface be wet? Or frosty? These types of applications require extremely strong adhesives, and probably a polypropylene or polyester facestock. An average paper label with standard all-temp adhesive would not do the job.
3) In what temperature will your label be applied? In what temperatures will your label be stored?
Each adhesive performs differently depending on the environment. Adhesives that do well in freezers may perform horribly in warm temperatures and vise versa. If you know you need freezer labels, check out this Freezer Label Buying Guide on how to pick out the right one for your company. Once you have your freezer labels, make sure to check out this article to learn all there is to know about correctly applying and making your labels stick in the cold.
This is a synthetic polymer that is the less-expensive option of the two. It has a higher initial tack quality than acrylic-based adhesives, but it is more susceptible to moisture and high temperatures., which may cause it to wear over time.
Exposure to chemicals or solvents may also cause the rubber to break down. If you tend to keep your labels indoors on plastic surfaces at room temperature, this is the adhesive for you.
Labels made with acrylic adhesive work well on a wide range of surfaces from wood and metal to glass and other outdoor items. It is resilient against moisture and holds up in drastic temperature changes and seasonal elements, such as ultraviolet light and freezing conditions.
It takes about 24 hours to completely adhere its surface, but it has the staying power to maintain its stick for years.
This is a hardy adhesive — however, it is much more expensive than rubber adhesive.
To make sure you know all the label adhesive jargon, we’ve compiled a list of popular terms you may encounter on your label buying journey:
Tack: The stickiness of a label. Higher tack = higher stickiness.
Wet-out time: This is essentially the time it takes for the label to form a continuous film between the facestock and substrate, which creates the permanent bond. If you place your product into the freezer before the label has wetted out, the label may not maintain its stick. Sudden temperature changes before allowing a label to fully wet out will lower its effectiveness. To learn more about freezer label wet-out times, see here.
Minimum application temperature: The lowest temperature at which the adhesive will function at the time of labeling.
Service temperature range: The temperature range over which the adhesive will function while the label is in use after the label has been applied and allowed to build to ultimate adhesion.
Hot melt adhesive: a rubber based adhesive that offers a very high initial tack. This allows the label to have an almost instantaneous wet out time that performs very well in subzero temperatures.
Emulsion acrylic adhesive: An economical choice for labeling your corrugated cardboard boxes. Featuring a good initial tack and a wide temperature service range, it’s commonly referred to as an “all-temp” adhesive due to its versatility.
Solvent adhesive: A permanent adhesive designed for plastics and glass. This adhesive can withstand very cold temperatures (such as blast freezing or in cryogenic lab conditions), autoclaving, and other demanding lab conditions. A synthetic label is generally required when using solvent adhesives.
The two most common core sizes are 1” diameter and 3” diameter. You may also see ¾” diameter core, but that one is less common (we’ll get into that in a minute).
The reason that core sizes differ is solely based on the kind of printer they are used in. Bigger printers use bigger rolls.
Labels on a 3” core diameter are used in industrial printers. These printers are bigger — about the size of a microwave — so they can fit rolls with larger cores.
Labels on a 1” core diameter are used in desktop printers. These are approximately the size of a toaster — much more compact than the industrial printers. Labels on a 3” core simply would not fit into this small printer.
The ¾” core is a little bit less common because these labels are used on mobile printers. While these printers are convenient to carry around with you, they are incapable of high-quantity printing. With that being said, not having to walk to the printer to print your labels, makes mobile label printing much more convenient. Many people use a popular Zebra QLN Printer for their .75″ labels.
When deciding which label to buy, it is important to know the amount of surface you have to work with which to apply to the label. You can’t buy a label that’s bigger than the surface that it is applied to. Labels are always identified by their measurement first. The first measurement is the width of the label and the second measurement is the length. For example, a 4×6 label, would measure four inches wide by six inches long. The width of the label is always the perforated edge of the label. If the label is not perforated, it is the edge of the label that comes out of the printer first.
Perforation and Application
Labels will either be perforated or non-perforated. “Perf” refers to the word “Perforation.” Perfed labels have a row of small holes punched in the liner between each label so that the labels can be torn off easily. If you are trying to figure out if you need labels with perforation or not, ask yourself this: “Are these labels going to be auto-applied, or will they be applied manually by hand?”
If you answered: “auto-apply,” then you want a label that is not perforated.
When you leave an auto-apply machine unattended, you expect everything to run smoothly. With a perfed label, you run the risk of that perf tearing, causing production to stop. During auto-apply, the liner spools after the label are removed to cleanly collect the waste. So, if that spool becomes detached, the whole process becomes disconnected and the liner will no longer be able to spool. On top of that, without the spool to pull the liner through the machine, the auto-apply would no longer be able to apply any labels! The best way to avoid this chaos is to simply order labels without a perf for your auto-apply machine. These rolls also come in larger outside diameters, because they are not confined to the shell of the printer.
If you answered: “by hand,” then you want a label that is perforated. This allows the user to rid of the excess liner to make the application process cleaner and more convenient. These non-perforated labels come in both direct thermal and thermal transfer.
Finished Label Format
Labels can come in rolls, sheets, and fanfold … and they all have their own uses. So many different industries use labels for all kinds of uses. It is not a “one size fits all” kind of deal. The following information will help you distinguish what format you should choose.
Roll labels are spun around either cardboard or plastic spools and can only be printed on thermal label printers (or less commonly — inkjet roll printers). As aforementioned, they come on 1”, 3”, and sometimes ¾” cores depending on the printer. In order to print, the machine feeds the blank label through one end and the final printed label comes out the other end one at a time.
This is the fastest and easiest solution for printing shipping labels, barcodes, and name tags where each one is printed uniquely. Additionally, due to the fact that rolls can be printed with thermal transfer technology, they can last much longer than sheet labels. If you have a high demand for labels, you can use roll labels to print quantities upwards of 500 per day.
The one pitfall of rolls is that they print into a messy pile unless you have a winder to neatly collect the labels. That’s where fanfold comes in handy.
Fanfold labels are manufactured with a certain perf to allow for neat folding into a concise stack. This is a HUGE time saver! Many warehouses have people folding the labels as they are printed, which is a big waste of labor that could be used elsewhere.
This also makes them easy to store, handle, and ship. Unlike for rolls, there is no need to winders or unwinders. The one downside is that they have to be fed into the printer from OUTSIDE the printer. However, as long as you have about a foot of space next to your printer, you’re good to go.
Sheet labels are laid out on a traditional 8.5” x 11” paper size, but can also come in both smaller and larger configurations like 8.5” x 11”, 11” x 17”, and 12” x 18”. These can be printed from inkjet or laser printers like the ones you have at home or at work. If you want to print a bunch of identical, but smaller labels — like return address labels — sheet labels are the way to go.
Chapter 5: Thermal Transfer? Here Is What You Need To Know About Ribbons.
If you intend to print thermal transfer, you are going to need thermal transfer ribbons. If you recall from earlier, thermal transfer technology uses a heat-sensitive carbon ribbon. The ribbon is melted onto the label as it passes over the thermal print head to present the image or text onto the label.
Choosing the right material for your thermal transfer ribbon will ensure that your labels stand up to the required quality and durability of the job at hand. The three basic ribbon materials are wax, wax/resin, and resin.
This is the most common type of thermal transfer ribbon. They are typically used with coated and uncoated paper stock due to its lower durability. They are inexpensive and good for shipping, shelf, bin, retail, and warehouse labels.
Wax / Resin
This is a hybrid of wax and resin-based ribbons. They create sharp, clear images on a variety of material types that are ideal for both standard and weatherproof labels. The price is a little bit higher than the standard wax ribbon, but a wax-resin ribbon is worth it when it comes to its resistance to heavy handling, moisture, and temperature changes.
This is the most expensive, but most durable ribbon type. They are typically used with synthetic facestocks and are good for labeling very sensitive medical applications and chemicals, textile or garment labels, automotive labels, and flexible packaging.
Thermal Printer Compatibility
Each printer model has its own functionality, and therefore, their own lines of compatible ribbons. The ribbons are classified into two categories: Coated Side Out and Coated Side In.
This refers to whether the ink is coated on the inside or outside of the ribbon, which would affect how they are wound and fed through the printer. Certain printers require one or the other.
Not sure how to tell? Here’s a tip! Stick a piece of tape to the outside of your ribbon roll. Did the ink stick to the tape? That is a CSO ribbon. If it didn’t stick, that is a CSI ribbon.
Coated Side Out (CSO)
The ribbon is wound out, meaning the ink coating on the ribbon is facing outward. To use with your printer, unroll it from the bottom and feed it underneath. These ribbons are Zebra compatible.
Coated Side In (CSI)
The ribbon is wound in, meaning the ink coating on the ribbon is facing inward. To use with your printer, unroll it from the top and feed it over. These ribbons are compatible with Datamax and Sato printers.
Seeing all the various ribbon sizes for the first time can be overwhelming, but knowing how to match your ribbon size with your label size can save you time and money.
Width – Choose the ribbon closest in size to the width of your label. For example, if you typically use a 4 x 6 label, choose the 4.33” ribbon. Otherwise, any unused ink on the ribbon will be wasted. Also, make sure you use a ribbon size that is compatible with your printer.
Length – You can use the length of your roll of labels to determine the length (in ft) of your ribbon. For example, Smith Corona’s 4 x 6 label is 510 ft long. A 4.33” x 1182’ ribbon would use about 2 rolls of labels. Doing the math may seem tedious, but it will prevent waste and save you money in the long run.
Core Size – While the standard ribbon core is 1 in, smaller printers require smaller rolls of ribbons. Therefore, desktop printers use 0.5 in core ribbons.
Well, there you have it.
You officially know pretty much everything there is to know about barcode and shipping labels. Something to brag about, huh? 😉
Now that you have all of this information, it’s time to get started with your purchase process!
For any questions, feel free to contact Smith Corona at firstname.lastname@example.org or 800-875-7000 and one of our sales representatives will be happy to speak with you.