88 research outputs found
Recommended from our members
A Simple Model for DoD Inkjet Frequency Response
This is the author accepted manuscript. The final version is available from the Society for Imaging Sciences and Technology.A simple linear model of piezo DoD inkjet print-head jetting output (drop speed, volume, momentum) provides an analytic prediction for the frequency response for steady state and initial printing streams from nozzles. The model has been applied to both existing commercial and development inkjet print-head devices.This work was performed under a UK EPSRC Impact Acceleration Knowledge Transfer Fellowship (grant no. EP/K503757/1). Xaar and other consortium members within the I4T (innovation in industrial inkjet technology) project (grant no. EP/H018913/1) gave permission to publish the results and also provided further support. Mario Massucci and Marko Dorrestijn (Xaar Cambridge), and Eva Singler and Ingo Reinhold (Xaar Sweden), all shared their piezo DoD print-head data for this paper
Recommended from our members
Multi Pulse Train Modeling of Piezo-Drop-on-Demand Inkjet Print-Head Response
Resonant oscillations set up internal fluid waves within a piezo-DoD print-head channel as a result of actuation drive pulses. Such waves will persist for some time after droplet ejection from the nozzle, and the residual wave amplitude can interfere (constructively or destructively) with all succeeding actuation drive pulses, potentially altering the speed and volume of successive droplets. As uncontrolled interference would worsen printing quality, residual waves are usually reduced by a combination of print-head design and waveform optimisation for better performance at continuous (steady-state) printing frequencies. However, the residual waves following any changes of printing frequency can influence “first” drops and short bursts of drops. Exact analytic expressions are provided here for the N-pulse burst DoD print-head response function with fixed printing frequency. The present paper explains the purpose and application of the model predictions to published piezo-driven DoD data. An examination of the effect of fluid properties, the identification of unexpected jetting behaviour and some issues with manufacturing prototype quality, tests of assumptions made in the simple model and extensions to the prediction of print-head performance using realistic complex waveforms are also discussed. An earlier shorter report, mainly introducing the multi-pulse train modelling approach and some applications within Xaar, was first presented at NIP31/DF2015.This work was supported by an EPSRC Impact Acceleration Knowledge Transfer Fellowship (Grant no. EP/K503757/1) and industrial funds from the Inkjet Research Centre at the University of Cambridge. Xaar and other consortium members within the I4T (innovation in industrial inkjet technology) project (Grant no. EP/H018913/1) gave permission to publish earlier results in NIP31/DF2015 and also provided further support.This is the author accepted manuscript. It is under an indefinite embargo. The Society for Imaging Sciences and Technology have not yet published it
Recommended from our members
Meniscus Motion Inside A DoD Inkjet Print-Head Nozzle
This is the author accepted manuscript. The final version is available from
the Society for Imaging Sciences and Technology via http://www.ingentaconnect.com/contentone/ist/nipdf/2016/00002016/00000001/art00087A new study of the jetting performance for drop-on-demand (DoD) inkjet print heads investigated meniscus motions inside the transparent nozzles of MicroFab inkjet print heads. A composite image representation of the observed meniscus motions, imaged at high resolution using a spark flash light source, was developed for our subsequent analyses of the influences of drive voltage and pulse dwell time and also the ink properties. At higher drive voltages a slow damped refill (following de-pinning of the meniscus from the very edge of the nozzle exit) was also clearly observed. This and many other interesting phenomena were observed with the composite images: internal bubbles that progressed through the nozzle region over relatively long timescales, internal break-off of the jet from the meniscus surface, satellite formation and merging, and the contact line de-pinning not previously observed before.This research was performed by CSR under the Undergraduate Research Opportunities Program (UROP) scheme, within the University of Cambridge Inkjet Research Centre, funded by Xaar Ltd. SDH supervised and held an EPSRC Impact Acceleration Knowledge Transfer Fellowship (grant no. EP/K5037574/1) for working with a Xaar R&D team during the initial part of this project
Vision 2040: Mining, minerals and innovation - A vision for Australia's mineral future
Droplet Misalignment Limit for Inkjet Printing into Cavities on Textured Surfaces
The control of droplets deposited onto textured surfaces is of great importance for both engineering and medical applications. This research investigates the dynamics of a single droplet deposited into a confined space and its final equilibrium morphology, with emphasis given to droplet deposition under print head misalignment, the effect of nonuniform wettability, and deposition of droplets with varying sizes. A multiphase pseudopotential lattice Boltzmann methodology is used to simulate the process of deposition. The print quality is characterized in terms of a parameter referred to as the wetted fraction, which describes the proportion of the cavity that is wetted by the droplet. Our results show how single and multiple axis misalignment affect the final equilibrium morphology, and it was found for comparable configurations that multiaxis misalignment resulted in a higher wetted fraction. Investigations into wettabilities of the substrate and cavity wall revealed how larger ratios of the contact angles between the two enhance the ability for the droplet to self-align within the cavity. Additionally, a range of uniform wettabilities between the substrate and cavity were found, which mitigate against misalignment. Investigations into varying droplet sizes relative to the cavity revealed how misalignment can be compensated for with larger droplets, and limits for filling a cavity with a single drop are defined. Finally, we explore the deposition with misalignment into closely positioned cavities where it is found that the spacing between cavities is a key factor in determining the maximum permissible misalignment
Recommended from our members
Review of digital printing technologies for electronic materials
Abstract: Direct printing methods have been used as manufacturing tools for printed electronics applications due to their cost effectiveness. In this review, the piezo-driven inkjet is discussed in detail since it is a mature technology and suitable for the production printing of printed electronics. In addition, other printing methods are considered for using higher viscosity ink and for producing smaller printed feature size. Various direct printing methods are compared in terms of jet mechanism, printing algorithm, and their applications. In particular high resolution printing methods using high viscosity inks, such as electrohydrodynamic jet, aerosol jet and micro-plotter are reviewed. To understand the recent status of industrial printing applications, display (liquid crystal display and organic light emitting diode) materials and printing issues are discussed. Finally, a brief overview of nano-particle metal based conductive inks is included because these inks have been widely used for printed electronics applications
Recommended from our members
Review of digital printing technologies for electronic materials
Abstract: Direct printing methods have been used as manufacturing tools for printed electronics applications due to their cost effectiveness. In this review, the piezo-driven inkjet is discussed in detail since it is a mature technology and suitable for the production printing of printed electronics. In addition, other printing methods are considered for using higher viscosity ink and for producing smaller printed feature size. Various direct printing methods are compared in terms of jet mechanism, printing algorithm, and their applications. In particular high resolution printing methods using high viscosity inks, such as electrohydrodynamic jet, aerosol jet and micro-plotter are reviewed. To understand the recent status of industrial printing applications, display (liquid crystal display and organic light emitting diode) materials and printing issues are discussed. Finally, a brief overview of nano-particle metal based conductive inks is included because these inks have been widely used for printed electronics applications
Recommended from our members
Review of digital printing technologies for electronic materials
Abstract: Direct printing methods have been used as manufacturing tools for printed electronics applications due to their cost effectiveness. In this review, the piezo-driven inkjet is discussed in detail since it is a mature technology and suitable for the production printing of printed electronics. In addition, other printing methods are considered for using higher viscosity ink and for producing smaller printed feature size. Various direct printing methods are compared in terms of jet mechanism, printing algorithm, and their applications. In particular high resolution printing methods using high viscosity inks, such as electrohydrodynamic jet, aerosol jet and micro-plotter are reviewed. To understand the recent status of industrial printing applications, display (liquid crystal display and organic light emitting diode) materials and printing issues are discussed. Finally, a brief overview of nano-particle metal based conductive inks is included because these inks have been widely used for printed electronics applications
Web-Based Collaborative Care for Type 2 Diabetes: A pilot randomized trial
OBJECTIVE—To test Web-based care management of glycemic control using a shared electronic medical record with patients who have type 2 diabetes
- …