The History of Thermographic Printing

Heard of thermographic printing? Not sure what it means? Thermographic printing refers to two separate types of printing which rely on heat to help create images or letters on sheets of paper. The simplest type of thermographic printing is where a source of paper features a coating that changes color upon heating. This type of printing is called thermal printing and is used within older fax machines and printers that print shop receipts. This type of printing is called direct thermal printing. Another complex printing form is thermal transfer printing, which melts the print off a selected ribbon and onto a sheet of paper. For those who are interested in thermographic printing, the following is a guide to its history and what it is today.

History of Thermographic Printing

Due to few records being kept when thermographic printing was being developed, there is little known about the first developments with this type of printing. However, it is known that thermal printing or raised printing dates back to the early 1900s. It is said that it was roughly developed in approximately 1905.

When thermography was first considered, it was a means to incorporate more novelty effects to the printing process. Before this, all additional effects were done by hand, because the technology for automated machines hadn’t been developed yet. Before thermographic printing was developed, a person would create effects by dusting powdered copal resin on wet ink, raising the substrate to a vertical position, before shaking the left-over residue from the substrate.

Copal is the common word used for a variety of varnish resins which consist of exudates that come from a number of tropical trees. Copal is lustrous, when hard, and it varies in hue, from colorless to bright yellowish brown. Upon heating in alcohol or organic solvents, it dissolves and is used in printing and varnish manufacturing. There are a number of different sources of copal, which, although similar in their physical properties, are different in their chemical makeup.

The piece would be introduced over a heat source such as a special hot plate, to help melt down the powder to create the desired raised printing effect. The process was known as Fried Printing because of the heat involved.

Up until 1915, thermography was a speciality craft before the first automatic machine was developed. It is said that Virkotype Company was the first business to produce an automated thermograph. By 1920, Carlson Company marketed the Vikotype machine and process in Europe. Because of its easier application, thermographic printing became more popular and lower-priced alternative to engraving copper or steel when adding embossing effects to ink.

With the introduction of the automated thermography machinery, it was more practical for new printers to be incorporated. After WWII, thermography became more popular. More printers started using the process due to new advancements in superior powders and advanced machines. Since 1900, thermographic printing has advanced greatly and is widely used as a preferred printing process that can add prestige to any stationery piece.

Thermography — Raised Printing Process

Thermography is the term used for the post print process which is achieved using thermography machines and traditional printing methods. These machines come available with three sections that feature a through-conveyor. These sections include:

• First Section — This section applies embossing or thermographic powder that’s made from plastic resin to normal paper or substrate. The selected areas for raised printing generally use slow drying ink which doesn’t consist of any hardeners and dryers. This means they still remain wet after the powder application. The ink is hardened and dried during the heating process.
• Second Section — This section uses a vacuum system, which removes additional excess powder from areas of the substrate that are un-inked.
• Third Section — This section is where the product is conveyed through a radiant oven where temperatures soar 900 to 1300 degrees Fahrenheit. This process takes up to 2.5–3 seconds to complete. The paper or substrate features an IR absorbance peak, compared to the amount of wavelengths used. Through paper conditioning, the temperature of the powder rapidly increases and starts to melt. When correctly adjusted, the largest filmed center areas reach their highest quality level as the paper or substrate exits the heater. During this process, the ink that’s melted solidifies as it cools.

This same process can be produced using manual powdering. The substrate or paper with the wet ink is lowered into powdered polymer. The sheet is moved back and forth so the powder rolls across the images. The powder is removed when the paper is positioned vertically and tapped lightly. The sheet of paper is fed through a heating system at a selected speed to achieve great quality results with the melted film. In craft applications, a heat gun is used to melt the powder.

Thermographic printing is used commonly on gift wrapping, greeting cards, business cards, letter heads, wedding invitations, and more. It can also be used for braille text printing. It is sometimes used for diploma printing as an effective and low-cost solution to engraved embossing.

Facts About Thermographic Printing

• Thermographic printing is quicker and more affordable than that of engraving or other printing methods.
• The best results of this printing method is seen on smooth surfaced paper. Textured paper or heavily grained paper gives a more ragged look.
• Envelopes and bumper stickers have all been thermographed successfully.
• Damp paper can cause the paper to curl under the heater, burn, or catch on fire.
• Different humidity levels can cause certain paper to curl. This can be rectified if the paper is turned over.

Conclusion

Thermographic printing has been used for the last century to create wonderful forms of stationery items which are sold worldwide today. Thermographic printing is a popular choice among many businesses and individuals, due to its high quality design and affordability. Remember, when purchasing your thermographic stationery, try to buy from respected and professional companies for the best results. So, do you like the appearance of thermographic printing? What was your last card that featured thermographic printing?