Thermal printers use heat to create the output. In this video, you’ll learn about thermal printers, feed assemblies, heating elements, and thermal paper.
If you’ve checked out in a store or you’ve received a package in the mail, then you’ve either received a receipt or a label on a package that was printed using a thermal printer. Thermal printers work by using white paper and applying heat to certain parts of the paper. Every part of the page that receives that heat will turn black, and we’ll be able to read the output on that page. That means there’s no ink. We’re not using any toner. Instead, we’re using the chemicals built into the page to create that final output.
Another interesting characteristic of thermal printers is that they’re relatively quiet. Usually, the only thing you hear is the motor that is used to send the paper through the printer, but the actual printing process is nearly silent.
We, of course, are using heat to create the final output on this page. That’s why we call it a thermal printer, because of that heat. But that also means that we need to be careful about what we do with that output. You don’t want to put that receipt or that label near another heat source, or that part of the page will turn black as well.
You’ll also want to be careful about using clear tape on your receipt or your thermal output. That’s because some clear tape will create a chemical reaction and turn that part of the page that it touches to white.
Because there’s no ink, there’s no toner, and there’s a very specialized type of paper that we would use, these thermal printers are relatively straightforward in their construction. The thermal paper is pulled through the printer using this feed assembly. And very often, it is simply using friction to be able to hold that paper in place.
This is a simple receipt printer. There is a roll of thermal paper that’s placed into the printer, and you can see the cover is up on the printer right now. At the very top, you can see that feed roller, and it looks like it uses a gear on the right side to be able to propel that roller and move the paper through the printer.
Here’s a better view of that feed roller. You can see it’s a relatively simple construction. We simply have a roller that is able to create that friction with the paper, and then you have a gear on the right side that turns it to be able to send the page through the printer.
The other major component of a thermal printer is the heating element. This extends the entire length of the printing area. Very commonly, this heating element is one single piece and does not move inside of the printer. This means that we can simply move the page in front of the heating element. Heat will be applied to the element in different places as the paper is going by, and you will see that the paper turns a different color once it is past that heating element.
You obviously can’t use regular paper inside of a thermal printer. Regular paper is not going to change color when it gets any heat, and therefore won’t be able to create any output in a thermal printer. Instead, you need a special type of paper known as thermochromic paper, or thermal paper. This is paper that has a special coating of chemicals on the outside that are designed to change color when heat is applied.
This is the type of paper you see when you’re using a cash register or a credit card terminal, or you receive a package in the mail that has a label. All of those different pieces of output were probably printed on a thermal printer using thermal paper. And if you touch the paper, you’ll feel that it’s a bit glossy and has a different texture than regular printer paper.