How Does a Thermal Printer Work: A Technical Explanation

How a thermal barcode printer works

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Thermal printers are pretty common these days. They are used in many applications, such as printing receipts, shipping labels, barcodes, and tags.

But how do thermal printers work?

Thermal printers, as the name suggests, work by using heat. They have an element called a thermal printhead which generates and passes heat onto the print media. The heat causes a change in print media which produces the desired print.

This, however, is not the whole story.

To understand how a thermal printer works, we need to take a deep technical dive. This article will explain how a thermal printer works in great detail.

So put on your learning hats, and let’s get started.

Working of Thermal Label Printers - A Detailed Explanation

As we mentioned, thermal printers use heat instead of ink or toner.

Thermal printers have three main components: thermal printhead, platen, and spring.

The printhead is responsible for generating heat. It has an array of energizing resistors (usually pins) mounted on a substrate and arranged in a matrix form. When an electric current is passed through these resistors, they generate heat.

Check out our printhead care guide for tips on extending the printhead’s life.

A printhead is generally controlled by a microprocessor like Arm Cortex-A7, RISC processor, and Qualcomm Snapdragon 660 processor.

The platen is a cylindrical roller that feeds the print media (e.g., paper, labels, etc.) into the printer. It is generally made of rubber.

The spring applies pressure against the thermal printhead. The spring ensures good contact between the printhead and print media so that heat can be transferred efficiently.

When a print command is given, an electric current is passed through the energizing resistors, heating the print head. As the print head heats up, the platen moves the print media under it.

Once the print head reaches its operating temperature (around 300°C), the spring presses the head against the print media, transferring the heat. This heat causes a change in the print media, resulting in the desired print.

Thermal printers offer two types of printing methods – Direct Thermal and Thermal Transfer.

Direct thermal and thermal transfer printing methods use the same basic working principle as explained above. However, they differ in how the heat is transferred to the print media and the type of print media used.

Let us now take a detailed look at how each printing method works.

Direct Thermal Printing Methods

The direct thermal printing process uses chemically treated thermochromic paper (commonly called thermal labels or thermal paper) as the print media. Direct thermal labels have ink coating, which prints the required text or images.

When a print command is given, the printhead targets the required area on the label and transfers heat to it. As the paper is heated over its threshold temperature, the coating turns black, resulting in the desired printed image.

The printhead comes in direct contact with the print media (thermal label) in the direct thermal printing method.

Thermal Transfer Printing Methods

The thermal transfer printing process uses a thermal ribbon and print media. Thermal ribbons are thin films that contain a dye and are covered with wax, resin, or a combination of the two on one side. In the thermal transfer method, the dye is transferred from the ribbon to the print media.

The ribbon is an intermediary between the printhead and the print media. When a print command is given, the printhead heats up and transfers the heat onto the required area of the ribbon. The heat causes the ribbon to melt and transfer onto the print media. This produces the desired print on the print media.

In thermal transfer printing, the printhead does not come in direct contact with the print media. Instead, the printhead transfers the heat onto the thermal ribbon, which then melts and gets transferred to the print media.

Check out our direct thermal vs. thermal transfer printing guide to learn more about the differences and applications of these two printing methods. The guide will also help you choose the suitable printing method for your business needs.

Advantages and Disadvantages of Thermal Printers

Here’s a table containing the advantages and disadvantages of thermal printers.

Advantages and Disadvantages of Thermal Printers
Advantages
Disadvantages
Generally rugged and built to withstand harsh industrial environments.
Generally heavy and occupies a lot of desk space.
Cost-effective in the long run as they do not rely on ink or toners.
Expensive and costs more than an average inkjet printer.
Quality printing results with high print speeds.
Thermal printed labels fade over time (the time depends on the printing method used).
Consistent printing results.
Thermal printed labels turn fully black when exposed to high heat.
Can print on a variety of materials such as plastic, nylon, and vinyl.
Restricted Label color options.
Low maintenance cost as they have a few moving parts.
Quiet operations.
Easy to use with only a few things like labels and ribbons to manage.
Can use recycled materials making them environmentally friendly.

Applications of Thermal Printers

Industrial Warehouse

Thermal printers are used in a wide range of applications. Some of the most common industries and applications that use thermal printers are.

Transportation and Logistics:

For printing shipping labels, receiving labels, return labels, packaging labels, inventory management labels, etc.

Manufacturing and Warehouse:

For printing barcodes, product identification labels, inventory management labels, compliance tags, quality assurance tags, etc.

Retail and Hospitality:

For printing receipts, price tags, POS receipts, guest passes, event tickets, inventory management labels, etc.

Healthcare:

For printing patient identification wristbands, specimen labels, blood bank tags, medication labels, etc.

Government:

For printing asset tags, parking permits, supply chain labels, ID badges, system administration tags, emergency labels, etc.

Transportation:

For printing public transportation tickets, parking passes, event tickets, boarding passes, baggage tags, etc.

Graphic Arts and Marketing:

For printing product labels, warning labels, nutritional information labels, tamper-evident seals, etc.

Conclusion

We hope you found this explanation of how thermal printers work to be both informative and interesting. 

If you’re looking for a thermal printer for your business, labeling needs, or any other application, be sure to check out our selection of high-quality thermal printers. We offer direct thermal printers and thermal transfer printers in a variety of sizes and price points. You can also check out our guide on the best thermal printers to help you choose the right one for your needs.

If you need assistance choosing a thermal printer or have other questions, don’t hesitate to contact us. You can contact us via the live chat widget below. Our team of experts will be happy to answer any questions you may have.

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