See us at the upcoming shows around the world:

InPrint USA

9 - 11 April 2019, Louisville

FESPA 2019

14 - 17 May 2019, Germany, Munich

PRINTECH/Rosupack 2019

18 - 21 June 2019, Russia, Moscow

The 3rd Annual InkJet Conference

On the 24 – 25th of October, 2016, one of DPS Innovations’ senior engineers participated in the 3rd Annual InkJet Conference in Dusseldorf, Germany.

Mr. Aleksander Bespalov made the following presentation on «DPS Innovations: Printhead controller boards for inkjet printheads and their role in the printing process»

What is TheIJC in short:

Showcasing technologies and spotting trends, enabling emerging technologies in digital printing, printed electronics and functional fluids. This event is a great opportunity to learn and partner with those that have been successful in enabling volume adoption of inkjet technology in manufacturing applications.

Here you can see the main conclusions of DPS presentation.

The presentation deals with the driver boards (or head personality boards as they also called), for inkjet printheads.

As you can see on this simple drawing (it is a sample of a typical wide-format scanning system), there are various printer components that need to have controller boards to drive them. There is Ink System Controller, Motion Controllers for X,Y, Z, Ink System Controllers that manage ink levels and ink pumps, Carriage board that receives signals from the positioning encoder and so on.

The presentation gives a detailed analysis of the head personality boards (or driver boards) and what role they play in managing printheads.

For example, here you can see one of DPS driver boards for a printhead made by Ricoh. For different types of printheads it is necessary to design and develop controller boards that will provide all of the necessary control signals to the printhead based on the printheads’ manufacturers recommendations.

Printheads differ from each other by design, mechanical construction, printhead control signals, nozzle voltage, waveforms, and ways by which data should be loaded into the printhead.

An efficient quality driver board needs to be developed in order to provide stable quality printing.

It is an important element which gives us proper drop formation and provides printing accuracy at a very high rate during printing with multiple passes.

Drop formation is directly linked to the waveform that needs to be adjusted based on the type of inks, media, and printhead model. A special dropwatching equipment is used for determining which waveform should be used in a particular case, and the driver board needs to support this type of waveform.

Driver board must support fast acceleration rates of the pulse, the average pulse duration is 0.5 milliseconds. If printing with one nozzle or all of 384 or 1280, the driver must provide even conditions for piezo element, so that there are no artifacts on the media.

Here is an example of a driver board not properly tuned to support a complex waveform.

As you can see, we have imperfect lines on this diagram.

Improperly supported waveform will create a situation where Piezo elements in one printhead will not work simultaneously, and as a result the volume of drops will be unstable, and printing speed will decrease.

You may see something similar to this nozzle test.

Here you can see, perfectly adjusted signals and here is the result

What factors influence this?

Well, there are several things that need to be mentioned in regards to the driver.

A lot of electromagnetic noise is created by servo motors, pulsating power sources and so on. In this case it is important to design the driver board with the right combination of capacitors, Electromagnetic filters, et cetera.

During printing , there is a need for sending and receiving data and loading the printhead without errors. In this case, data recovery is implemented by correcting the errors on the fly with a specific algorithm.

To summarize, each printhead type requires individual approach when making a driver board for it.

Properly designed driver board, that can provide high stability and adapt to various waveforms is no less important than choosing a proper ink or material to print on.

In conclusion, the author stresses ones again that he wanted to mention a general idea of what factors are considered when making a control board for a printhead.

It is our hope that this presentation is useful for you.