Bashing Heads

Explaining what are the differences with the inkjet heads in the market today

What are Piezo, Thermal and Valvejet technologies

Last I was at an industry tradeshow, lots of new stuff and great to meet industry leaders and fellow industry members. At night while sitting at the hotel bar, I overheard a hefty conversation about inkjet head technology.  Yes, inkjet head technology is still a big discussion at tradeshows, specially at the hotel bar for some reason.  
The first guy was arguing that his company XYZ was making the fastest head and largest output on the market, the one sitting next to him was agreeing, it was fast but his company ABC had a print head that was wider and therefore could print more in the same time, making it much better.
Last of the three guys was from FGH and his company was proud to be the one with a replaceable head, so no service issues and fast changing. He also mentioned that with his technology he could keep on adding heads if needed. ABC asked why add heads if you have a big one that you could stitch together in one long seem-less printhead.

This would be compact and fast. Well, FGH mentioned, you don’t need to have a complicated large long head, especially if you needed to replace it. He continues explaining about the headache you would have replacing one head.  With his technology you just would replace what was broken and you’re up and running in no time.  XYZ continued that with the technology his company, you would only need to replace heads after 2-3 years. So where is the problem. Finally they all agreed to disagree on this topic and ordered more beer.
As the beer arrived they continued with print head drop size, where one head was able to print with 2 pico-litre the next one was proud to say that 11-12 picolitre was a lot better as density and coverage was so important. One commented that if you want ink on the substrate then the valve jet was your solution, with up to 260 pico-litres and a resolution of 35dpi it could print on anything as long as you looked at it from a kilometer away. They all busted into laughter.

With still beer in the glasses, the discussion continued, but now about the differences between piezo, thermal and valve jet technologies, as all of these are inkjet printheads the discussion became hard and less friendly. The XYZ company man told everybody that it did not matter as piezo as the most common technology and that most of the heads are piezo heads. FGH started to laugh, his company has made more thermal inkjet heads than anybody in the world, so no piezo is not the only technology. The rambled on about the technologies and what was better and why…

Termal Inkjet head

Piezo Inkjet head

ValveJet Inkjet head

So how about the size of the heads for this flatbed table. Big heads like from ABC could make the carriage weight very high and would make the printer slow and bulky.
Not only that the print would be very heavy to carry all this weight. It would be able to print really fast.  In my opinion the best solution would be a print head that is fast, relatively small (I can use multiple heads so more colors or more speed) and piezo based if you are designing a flatbed UV printer. I decided to leave the gents in there evening discussion and started to relativize there statements.  Was size, speed, technology and drop size worth the discussion. No, the core is what are you going to use the technology for. The word here is “application”.  Let me go deeper into this, let’s take a UV-ink based flatbed printer. 

Here the size of the droplet is important if you want to have a sharp small text (say 2 points), at the same time you would like to have the possibility of a variable drop size.
This gives us a better coverage and a more uniform image buildup. Specially if you have large one color high density blocks on the print. Think of logos and other vector data. As thermal technology is not recognized today as the multi drop technology is still can produce very well with water based resign based inks but it would not be the best solution for UV inks and the UV curing lamps.

Applications is the word

Again the word is applications, this is why all manufactures make printers for specific markets and trends.  Textile printers are mostly piezo based, why because of the accuracy, speed and drop size. CAD printers are mostly thermal (bubble-jet) inkjet based, why because of the relative low cost easy install and water based dye or pigment inks and yes flatbed UV inkjet printers are mostly equipped with a piezo head technology.
So if you are looking for a new printer don’t jump on the technology train, think what will I be producing, what is my need and how much do I need to print.  Putting all these things in order, you might opt for the most expensive device because the ROI would be better than the cheap one.

Take your application to the next level by comparing the quality of the output on your application not the head type. There is a right printer out there for your needs.   Just a word of caution technology is changing so fast that this blog could be obsolete before you even read it. I just wanted to give you a heads-up on what the market has to offer to your business and how you can benefit from one evening of discussions on a trade show.  

Mike Horsten
ZEMT Consultancy and freelance writer mike@zemt.info  
All brands names are fictitious and no reference is made to any specific brand