Linear motor platforms speed print head testing

Edited by the Engineeringtalk editorial team Aug 18, 2005

Anorad has produced a custom design split-axis, linear motor driven XY motion platform, specifically for testing and the alignment of industrial inkjet print head assemblies.

Anorad has produced a custom design split-axis, linear motor driven x-y motion platform, specifically for testing and the alignment of industrial inkjet print head assemblies.

Because the performance of the test system is considerably superior to that of the print head itself, any deviations and defects in the latter can be detected.

The design concept of the system was based around the requirements of the end customer who needed to be able to test their range of large format digital print head assemblies, but the relatively simple concept behind the design could be adapted for use with almost any high specification industrial printer.

Historically this kind of precision alignment and testing was achieved manually.

However, this is extremely labour intensive and could, literally, take days of a skilled technician's time.

It also produced excessive wastage, in terms of test prints on various substrates, which is now reduced to a minimum.

Furthermore, global networks of printers are now able to have minimum downtime due to the use of Anorad's custom motion platform.

As the pre-test and pre-alignment of the print head assemblies has been so successful, the replacements are simply shipped to the end user for quick and easy integration into the industrial printers.

Added value has also come from the elimination of the need to send out maintenance engineers to a site.

"When a new application has been identified, Anorad's Engineering department take the initiative to come up with the best and most cost effective solution", explained Andrew Holmes, of Anorad UK.

"We work very closely with our customers and conduct comprehensive design reviews at every stage".

"As a result, we are able to produce custom built machines to meet the most demanding requirements".

In this application the print head is attached to the upper axis and the test substrate to the lower axis.

The upper axis performs a scanning movement from one side to the other while the digital printhead prints onto the substrate beneath.

When the printing movement is reversed, the lower axis makes a step movement.

The next printing movement is then performed.

With the use of digital camera technology the print head is adjusted to ensure correct alignment and the assembly can be approved or, if necessary readjusted or rejected.

The scanning movement is performed at a speed of 0.5m/s +/-1%.

During the entire movement an accuracy of 3.5um for the upper axis and 5um for the lower axis is achieved.

This is measured at the point of interest, which in this case is in line with the print head.

This represents a significant advantage over most of Anorad's competitors, who don't normally state their specifications this way.

"As a result, the accuracy quoted by such companies can be wide of the mark at the point of interest", explained Holmes.

The straightness and flatness of movement is +/-1um/25mm for both axes.