In recent years, the popularity of LED curing in wide format printing has soared. LED curing is more efficient and safer than older curing methods, and the technology is developing and becoming more powerful all the time. With a wide variety of benefits backing LED curing and manufacturers widely adopting this newer technology, it seems we have come to the end of the mercury bulb era in UV curing for wide format printing.

Let’s take a closer look at LED curing and why it’s taken over from bulb curing methods.

What Is UV Curing & UV Curable Ink?

The UV curing process is a chemical reaction initiated by ultraviolet light. The UV light starts a process called polymerisation where the ink molecules ‘cross-link’ or bind together into a solid surface. In the UV curing process, there’s no evaporation of the inks, no solvents, and the ink sets very quickly giving you a set print in a matter of seconds.

UV curing is used in many different settings outside wide format printing too – from 3D printing to setting gel nail polish in beauty salons! The technology for LED curing has been around for some time but it’s taken relatively recent advancements to increase power and efficiency to make it an attractive choice for wide format printing.

As well as the technology behind the LEDs, the manufacture of LED UV curable inks has been improving. Initially, UV curable inks were fine-tuned to the needs of mercury bulb UV curing. With the difference in performance between mercury bulbs and LEDs, UV ink formulas needed to be updated to work seamlessly for the LED curing process. Using UV inks designed for mercury lamp curing with LEDs could lead to an unsatisfactory cure, adhesion issues and tacky surfaces. As LED curing has become more widespread, more LED UV curable inks have come to market allowing a quality print at a competitive price and, therefore, making the technology a more viable choice for printers.

UV Curing: LEDs vs Mercury Bulbs

To understand the differences between LEDs and mercury bulbs, we need to look at how they both operate. Although they both have the same end goal for UV curing, their technology is quite different.

LEDs

LEDs are a semiconductor which can convert electricity into light. The more efficient the LED, the more of the electrical energy they can turn into light. LEDs produce UV light at a relatively narrow region of the UV spectrum.

Mercury Bulbs

Mercury bulbs create light by exciting mercury atoms with electricity. An electrical current passes through and excites mercury atoms and noble gases to form a super-heated plasma. In the plasma state, the mercury irradiates light, which covers a broad spectrum from UV to visible and infrared light. A significant amount of heat is used in this process – mercury lamps often operate at over 900℃.

As we can see, the difference in how LEDs and mercury bulbs work results in two main differences: the amount of UV light they emit and the temperature at which they operate. Whilst LEDs may not be as powerful as mercury bulbs, they are constantly improving which will only lead to more efficient UV curing. Although they are more powerful, mercury bulbs have to include mercury – a dangerous substance – and operate at very high heats which requires considerable management. It is for these reasons that LED curing is only gaining in popularity, whilst there are valid reasons to move away from mercury bulb curing.

Benefits of LED UV Curing

There are many reasons that LED UV curing has taken over the wide format printer market. Here are some of the main advantages of LED UV curing in wide format printing:

  • LED curing operates at low temperatures – this means complex cooling systems aren’t needed and heat sensitive substrates, such as plastics or foamboard, can be printed on with ease
  • LEDs use a lot less energy than mercury bulbs and only need to be on at the time of printing, resulting in significant savings on operating costs over a printer’s lifetime
  • LEDs don’t include mercury which is a hazardous material; items containing mercury need to be specially disposed of as hazardous waste at the end of their life
  • The reduced energy consumption and lack of mercury make LEDs a more environmentally friendly option
  • LEDs have a much longer lifespan than mercury bulbs and you won’t experience a reduction in performance as they grow older. With LEDs lasting up to 20,000 hours, many printers won’t require LED replacements during their lifetime
  • LED curing systems are lighter and simpler which also makes them cheaper to build, helping to reduce the total cost of the printer
  • LEDs are simpler and more durable than mercury bulbs and they don’t involve extra parts like shutters or mirrors which means there’s fewer parts to break or replace
  • Although mercury bulbs produce more light, a lot of it isn’t useful UV light which contributes to the curing process, and often this extra light needs filtering out

 

Once you understand how LEDs work and all the benefits of LED curing, it’s easy to see why LEDs have replaced mercury bulbs and why manufacturers have moved away from the older curing technology.

Whilst LED UV curing is clearly the future, there are understandably still a lot of companies out there with wide format printers using mercury bulb curing systems. Should you need replacement UV bulbs or printer parts for your wide format printer, have a browse of our high quality spares or get in touch with our experts for assistance.