Frequently Asked Questions
 

The primary active component, the Actuator, is made from a piezoelectric material with a number of micro-channels cut into it. It is driven by applying a voltage waveform that causes small deflections of the actuator channel walls. These deflections set up acoustic pressure waves that travel up and down the channel and create the drops at the nozzle plate. This approach is not a push mechanism and therefore minimises mechanical stress resulting in high efficiency and long life for industrial applications.

Firstly, both printhead types are drop-on-demand printheads so they have that in common. As for the differences - all Xaar printheads use the activation of a piezoelectric material that creates an acoustic wave to generate drops. This is highly efficient and low-stress making it ideal for industrial print applications. It is also incredibly versatile through compatibility with a wide range of inks and functional fluids. Thermal inkjet printheads effectively boil an aqueous fluid (ink) to propel tiny ink droplets through a nozzle limiting its application to low-viscosity, water based fluids.

Xaar’s latest printhead architecture, the Hybrid Side Shooter™, employs a clever ink re-circulation approach to deliver very high operational reliability, self-recovery and low maintenance (see ‘What is TF Technology™?’ below). Xaar creates piezoelectric printheads that have a high nozzle density through utilising the shared walls between channels to fire both sides of the channel. This is called shared-wall architecture and gives rise to a native nozzle density around 180 nozzles per inch. In addition some printheads in the range use a ‘chevron’ actuator which uses 2 pieces of piezo material fused back to back. This forms a chevron shape when a voltage is applied and is even more energy efficient and reliable in long-term commercial use.

In Xaar inkjet terms and for most applications drop sizes range from 80pl down to 6pl. The drop size you require depends on the application you want to fulfil. With Xaar you can choose whether you use a fixed drop size (binary) printhead or variable drop size (greyscale) printhead or printheads that can do either (selectable). These options are delivered through XaarDOT™ (Xaar Drop Optimisation Technology). For graphics applications the smallest drop size determines the resolution of the image (note it is not the dpi but the drop size) and large drops for low-resolution images are perfect for longer viewing distances. For closer viewing variable sized drops give a much higher quality image – apparent resolution – for a relatively low dpi (or npi). For single-pass printing you need the range of small drops for fine detail up to larger drops that achieve full coverage in one pass.

This comes down to a combination of several factors. What is the typical viewing distance (in graphics applications), what level of quality you want to present and what ink and media you want to use. The higher the required resolution the smaller the drop size required. The longer the viewing distance the bigger drops you can use. With XaarDOT™ (Xaar Drop Optimisation Technology) you can choose the drop size and drop formation options that best suit your application.

Scanning printing builds up an image by moving backwards and forwards across the media whilst the media is advanced in small steps. Lines/rows of dots are interleaved creating the image. As with your home inkjet printer this is relatively inefficient in the amount of non-printing time whilst the carriage turns around. The benefit of single pass printing is that you get to print 100% of the time by moving the media (sheets or web) under a fixed printhead arrangement (print bar). A key consideration therefore is how to get fine detail as well as full coverage in this single-pass under the printheads and this requires either a large number of nozzles (printheads, cost) or the ability to print variable sized drops (greyscale) out of each printhead (fewer printheads, lower cost). To understand more about Single-Pass Printing click on the link below.

Xaar offers the widest choice of printheads to suit a wide range of applications. Your selection decision will be based on the requirements of your application in terms of drop size and range, ink type, print swathe, integration and replacement approach and so on. For a comparison of the key features and parameters of the printhead please refer to our Printhead Matrix by clicking below. For further help and advice please contact us and we’ll happily discuss your requirements with you.

Our greyscale printheads are optimised to provide the range of drop sizes combined with high nozzle density required for high-speed single-pass printing. In particular the Xaar 1001 (click below for more info) also incorporates TF Technology™ which offers extremely high levels of operational reliability and long mean time between maintenance – both key to production environments. Clearly other factors should be considered – swathe width, resolution, cost, etc.

It stands for Hybrid Side Shooter. In relation to electronic devices the term hybrid is used to describe a component bonded to a substrate. The PZT actuator in the 1001 is bonded to such a substrate hence our use of the term “hybrid”. The Side Shooter aspect refers to the fact that the nozzles are off the side of the ink channels in the actuator to facilitate the re-circulating ink capability as opposed to being an end-shooter where the nozzles are at the end of the actuator channels.

TF Technology™ is Xaar’s unique ability to flow the ink past the back of the nozzle in the Hybrid Side-Shooter printhead actuator architecture. The through-flow of ink across the back of the nozzles provides a number of benefits: easy fill of the printhead, increased reliability and self-recovery, minimal maintenance and therefore reduced ink wastage through purging. In addition the internal design of the printhead for TF Technology ™ facilitates easy cleaning and colour/fluid changeover. The Xaar 1001 printhead is unique in the marketplace in offering this feature.

For each printhead and application we have approved one or more inks. We work with the widest range of ink suppliers in the industry to provide our customers and their customers with the choice of ink supplier they would prefer. Please refer to the table of Approved Inks by clicking below. If you can't find what you're looking for please use the Contact Us link opposite.

There are various factors that affect the life of the printhead. We have not yet found a failure mode in the active components of the printhead in working practice because printheads are typically damaged through other physical effects such as damage to or blockage of the nozzles. With most applications the duty cycle for each and every nozzle is well below 100% and therefore Xaar’s implementation of piezoelectric inkjet will last for years, which is why it’s called Industrial Strength inkjet.

Key to extended life is good maintenance practices and systems as well as good quality ink and filters. Different manufacturers take alternative approaches to maintenance but best practice seeks to minimise physical contact with (or abrasion of) the nozzle plate. Steps to avoid ink curing or drying in the nozzles should also be considered. Good quality inks that are Xaar Approved or carry the Xaar Hologram are recommended.

Our Inkjet Development System (IDS) provides all of the components you need to evaluate Xaar inkjet in your application. It includes a Hydra Ink Supply System, the XUSB, your choice of printheads and ink.

Our Inkjet Development System (IDS) provides all of the components you need to evaluate Xaar inkjet in your application. It includes a Hydra Ink Supply System, the XUSB, your choice of printheads and ink. These systems are therefore for customers who intend to develop inkjet printing systems or to develop inks using our inkjet printheads. It is for you to provide the transport/mechanical system appropriate to your application. Included with each IDS is 2 days of engineering support to assist you with set up.

Please contact our sales team on +44 (0)1223 423663 for further details. We only supply printheads to Original Equipment Manufacturers (OEMs). Our OEMs supply spares for their machines so please contact your original supplier for replacement printheads.