Whenever we make a purchase at a shop or at a supermarket, more often than not, we see a little printer next to the cash register at the checkout counter. That little printer, called a thermal transfer printer, prints out receipts, and is a minute detail in an elaborate system called point-of-sale system or POS. Have you ever wondered how a thermal transfer printer works?
As its name implies, a thermal transfer printer is dependent on heat. It makes use of a special form of paper, called thermal paper, and a ribbon with solid ?ink? or resin with a polyester film backing. When you open a thermal transfer printer, you will see the rolled thermal paper nestled within, just beneath the printer head. Sandwiched between the thermal paper and the printer head is the ribbon.
When the thermal transfer printer is used, what happens is that the printer head generates heat. Just what pixels or dots are heated on the printer head depends on the characters that are being printed. The heat is then transmitted through the polyester backing of the ribbon, and it causes the resin or the ?ink? on the ribbon cartridge to melt. When the ?ink? melts, it comes into contact with the thermal paper to form the characters.
This process happens very fast. Ideally, the printout speed of a thermal transfer printer is 12 inches per second, but most machines being used in shops or supermarkets make do with speeds of only up to 6 inches per second.
The process of how thermal transfer printers generate their printouts is quite simple. This is also the principle behind how thermal fax machines work.
The ink on the ribbons used on thermal transfer printers are not really ink. This substance is often made of wax, a mixture of wax and resin, or pure resin. Ribbons made with pure wax are the least durable of the three, and they are often used to print out barcodes and labels.
Ribbons made with mixed wax and resins are a lot more durable than those made of pure wax. They are used for printing finer images on smoother paper, or on film-coated paper. Despite their increased durability, printouts made from thermal transfer printers using ribbons with mixed wax and resin should still be protected from moisture and chemical exposure.
Ribbons made with pure resin are not used for POS and checkout systems. They are for printing on plastics. The printouts made from these ribbons are the most durable, and they require minimum protection from chemicals or the elements.
Thermal transfer printers are simple machines that work using simple processes. And yet, they are a minute but definitely essential detail in an entire POS system.
Are you dissatisfied with the print quality of your thermal transfer or direct thermal printer? Do they have unwanted lines and/or blank spots in the print? If so, your thermal transfer printhead might need cleaned or even replaced. The printhead is the most critical component of your thermal printer and one of the most delicate. Before deciding whether or not you need a new thermal transfer printhead, you should first clean it properly. You can clean a printhead by rubbing it with an alcohol pad or better yet, buy ribbon equipped with "Cleanstart".
What is "Cleanstart" ribbon? "Cleanstart" is a barcode ribbon that has a special printhead cleaning feature at the start of every roll from IIMAK. IIMAK is one of the largest US based manufacturers of barcode ribbon. After installing your new roll of ribbon into your printer, simply close the printhead at the start of the white "Cleanstart" cleaning strip and pull it through the closed printhead. Reopen the printhead and feed the ribbon through for the final setup and installation. Close the printhead and begin printing.
If the quality of print is not improved then more troubleshooting is needed. Many of these printers are very temperamental and the slightest adjustment can make all the difference. Check the heat setting on the printer to make sure it is hot enough. This can usually take care of some of the lines or fading in the image that is printed.
The next step in troubleshooting the printer would be to check the platen roller. That is the rubber roller that is right under the print head. Many users will damage the platen roller by taking a knife to it to get excess label adhesive or paper stuck to the roller off. This is a MAJOR no-no! NEVER take a knife or blade to the platen roller. This roller is critical in keeping the quality of print consistent. Look for a nick in the roller and if there is one, have a service representative replace the platen roller.
So there is no nick in the platen roller? The next step is to inspect the printhead with a light and look right on the black sensor that meets the labels when closed. You will have to open the print head to see. Check the printhead for white spots. White spots on a printhead indicate damage and wear from the course of its print life. If there are white spots on the printhead, this is a good indication that it is time for a new printhead. The printhead life can vary in length based on how well it is maintained. Wiping your printhead with an alcohol pad before every use will ensure its cleanliness and protect it from residue buildup. The same positive results will occur with the proper use of a "cleanstart" ribbon. Proper maintenance will result in the maximum life span of the printhead.
Now, if your troubleshooting indicates that you need a new printhead, then there are a few decisions to make. Do you want to buy the exact OEM printhead? Or do you want to buy a quality compatible printhead? Many times it is the same manufacturer that makes both. There are very high quality off brand printheads on the market that can save you a lot of money. OEM printheads are usually required for some warranties, but if you can, we suggest going with a private brand, high quality printhead as a replacement because they are much less expensive and work just as well.
Both John C. Arkin & John Barth are contributors for EditorialToday. The above articles have been edited for relevancy and timeliness. All write-ups, reviews, tips and guides published by EditorialToday.com and its partners or affiliates are for informational purposes only. They should not be used for any legal or any other type of advice. We do not endorse any author, contributor, writer or article posted by our team.