Thermal printhead explanation
The thermal printhead is the most important part of the thermal printer. It is the part which is printing on the labels or on other media. Thermal printheads are printing without ink or toner. They can print direct on thermal paper (direct printing) or with a therrmal transfer ribbon on many kinds of materials. Thermal transfer ribbons is most af time called as TTR
The history of a thermal transfer printer
Thermal printing (printing with TTR) is excisting allready many years. This technology was an invention of the japanese company Sato. In the middle of the 80's started this technology to be active in industrial and identification systems based on use of barcodes.
The most important sectors where is used thermal transfer printing is: Marking and coding of products and warehous activities.Thermal transfer printing is worldwide implemented, and still growing annually.
The biggest advances are no ink or toner necessary, printing possibility on many different materials, for example paper, carton, PP, PE, textile etc. Also thermal printing does have a high speed with a low noise level.
The construction of the thermal printhead
The thermal printheads is an electronic part. On one line there are many dots (heating elements) The more dots per mm, the better the printquality.
8dot/200dpi means: the printhead has 8 dot per mm. The printheadresolution is equal to 200DPI (dots per inch)
12dot/300dpi means: the printhead has 12 dots per mm. The printheadresolution is equal to 300DPI (dots per inch)
200 and 300DPI are standard resolutions in industry and trading envorinment, however currently there are also already printers with 400 and 600dpi.
The thermal printhead is the most sensitive and vunerable part of the thermal printer, and mostly also the most expensive part of the printer. Besides that the thermal printhead is a wearing part, and his lifespan is among others depending of his maintenance.
In practice there always excist pollution on the printhead which is easy and necessary to be cleaned up.
This pollution are residues of paper, glue, thermal transfer ribbon but also other environmental pollutions.
Pollutions on the printhead are causing bad printquality and temperature deviations which can damage the printdots. Thermal printheads are costing depending of there type and brand between € 100,-- and € 2000,--
Cleaning the printhead is costing only 10sec. and € 0,50
Why are thermal printheads wearing out?
Heating, cooling and mechanical pressure are the main reasons thermal printheads fail. A thermal printhead consist of dots (small heating elements). These dots are individually electronic controlled. The heat from the dots is then transferred to either the direct thermal paper (media) or thermal transfer ribbon. The heat from the dot pattern produces the text, barcode or image on the labels. Because the dots must be heated and cooled very rapidly, and there mechanical friction with the ribbon or paper passes against the printhead, the printhead will eventually wear out. As the printhead ages, the output will become lighter or sections of dots may stop heating and cause voids in the print.
How can I prolong the life of my thermal Printhead?
There are some simple steps you can take to prolong the life of thermal label printheads.
- Clean the printhead regularly, as described in the user’s manual. Dirty printheads produce less than optimal output and residue from the printing process can cause uneven heating or dissipation of heat by the dots.
- Use the right type and good quality paper type and thermal transfer ribbon. Wrong types causes additional mechanical and thermal wear on the printhead.
- Use the lowest print speed setting that produces acceptable results.
- Alsways print with materiaal in the printer (media and /or TTR)
- Try to run prints at room temperature where possible. Lower ambient temperatures require more energy to be sent to the dots to produce the print. Excessive heating and cooling of the printhead dots will shorten the printhead's life.
- Use the lowest contrast setting you can. Higher contrast means more heat to the printhead. Higher heat translates to a shorter life span.
- If your printer has a printhead pressure adjustment, use the lowest setting possible. This will reduce the amount of friction the printhead sustains during printing.
Make sure you are not printing off the thermal transfer ribbon. Thermal printers are designed to use the transfer of heat from the printhead to the print TTR as the primary cooling method. If the dots on the printhead are not printing on TTR, they are not cooling properly. Also be aware of the fact that if you are using preprinted labels they may have been printed with the correct inks and topcoatings. Some white inks namely contain abrasive particles. A main component in white in is titanium dioxide, which is used as a grinding agent in some industries. Allways inform about this at your labelsupplier.
How to clean your thermal printhead? Click here