1,802,681 research outputs found
Continuous direct ink jet printing.
No full textPhDThis thesis describes the preparation and continuous printing of zirconia ink under different
conditions, as well as the development of silver inks, for the same purpose.
The dispersion of sub-micrometer zirconia powder in industrial methylated spirit using other
additives such as dispersant and binder was investigated with different mixing methods and
at varying powder and binder contents. The use of high shear mixing by triple roll milling
followed by ultrasonic disruption as well as adequate sedimentation and filtration produced a
homogeneous and stable ink of 2.5 vol. % ZrO2. The ink could be printed directly and
continuously on a commercial jet printer without interruption of any kind and the phenomena
occurring during printing were investigated. The optimum modulation frequency for
printing was determined with the generation of pear-shaped and symmetrical droplets.
Printing was made on substrates of surface free energies lower and higher than the surface
tension of the Zr02 ink. Powder migration was observed within a relic of the printed dot on
the second type of substrate. Layers were also overprinted on the second type of substrate
by varying the following: print resolution, printing interval, print area, drying conditions and
ink powder loading. These series of prints were accompanied by the appearance of ridges,
spattering and non-vertical walls and the effects were investigated.
The wettability and shrinkage of droplets of the ceramic ink was also studied in-situ by
monitoring the evolution of contact angle, width of ink-substrate interface and droplet height
with a video camera. The shape of the droplet experienced different dynamics on different
types of substrate.
Lastly, the sedimentation behaviour of ethanol-based silver inks dispersed with different
types of dispersant was investigated with respect to the sediment volume and half-value
time. Deflocculated ink was obtained at a low dispersant level and powder loading
Visualization of toner ink adsorption at bubble surfaces
Get PDFFlotation deinking involves interactions between inks particles and bubbles surfaces. These interactions are very difficult to observe directly or to quantify in bench-scale experiments or mill operations, making it difficult to evaluate effects of process conditions such as bubble size and solution chemistry on deinking efficiency. This paper presents images and measurements of toner ink interactions with bubble surfaces in laboratory-scale flotation processes. Stable adsorption of toner ink was observed at surfaces of stationary and suspended bubbles for several system chemistries. Interactions of toner particles and bubbles were quantified by high magnification and high temporal resolution digital videos obtained in bubble flow facilities creating both stationary and flowing bubbles. Large (>200 micron), flat toner particles adsorbed to bubble surfaces by single contact points. Smaller toner particles formed very stable complexes in fatty acid chemistries. Desorption of toner ink from bubble surfaces was not observed, even for vigorous flows. Bubbles were observed to be fully covered with toner after 4 minutes of residence time in the suspending bubble flow facility. Initial estimates indicate that bubbles with diameters of approximately 1 mm carry more than 1 mg of ink per bubble
The use of embellishment techniques with ink jet printed repeated designs
No full textThis paper will discuss the use of devore printing as an additional design feature to ink jet printed fabrics. Ink jet printed fabrics are an ideal basis for bespoke fabrics to be generated in small-scale productions. To begin with this paper will discuss the production of ink jet printed fabrics in repeat using textile CAD software. The original design will include all embellishments as part of the original repeat; as an overlay.
Before the application of a devore effect, the ink jet printed fabric will need to be finished conventionally, then the shrinkage which occurs can be taken into consideration and the overlay modified in repeat.
To conclude the paper will discuss the extension of this process into other possible methods of embellishment such as overprinting and resist techniques, which can be used with ink jet printing onto textiles. These techniques will display alternative methods for producing high quality customised fabrics
Combinatorial ink-jet printing for ceramic discovery
No full textPhDAn aspirating and dispensing printer established inside a robot gantry equipped
with furnace and measurement table is used to prepare thick-film combinatorial
libraries. Implementation of series of screening tests for ceramic inks that address
stability against sedimentation, evaporation and particle segregation during
drying, has provided a series of calibration inks can be used for calibration of
this printer. The instrument can assemble ceramic mixtures with compositional
accuracy of 1-3 wt %. By changing the amount of dispersant used in the inks or
by printing onto a porous substrate, the geometry of residues from dried ceramic
ink droplets can be modified to facilitate property measurements and uniform
composition, as planned, can be achieved. The same material prepared in three
ways, in the form of dried ink, ink-jet printed as for a combinatorial sample and
by conventional compaction gave similar dielectric measurements. A
combinatorial system has been developed so that combinatorial libraries can be
printed, fired and screened automatically. A ternary A1203-TiO2-ZrO2 system
was first studied using the developed combinatorial method.
The particle segregation during drying of multi-component ceramic ink drops is
not due to preferential sedimentation unless dispersant addition is restricted. The
segregation is due to the partitioning of particles between the growing peripheral
'foot' that develops during drying and the diminishing liquid pool which contains
vigorous recirculation flows. Better dispersed particles remain in the pool and
hence are found in excess on the upper surface of residues. Less well dispersed
particles join the 'foot' earlier in the drying process.
The contact angle and height of droplets containing large amounts of dispersant,
steadily reduced during drying until a minimum value was reached; the contact
diameter being almost unchanged during drying. These droplet residues retained
a dome shape. Droplets of suspensions containing small additions of dispersant
terminated in a 'doughnut' shaped residue
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Dependence of Drop Speed on Nozzle Diameter, Viscosity and Drive Amplitude in Drop-on-Demand Ink-Jet Printing
Get PDFResults of recent experiments and numerical simulations are presented, which have been used to establish empirical rules for
the dependence of drop speed on nozzle diameter and drive amplitude for Newtonian and non-Newtonian fluids printed with a
range of different ink-jet print-head technologies. Experiments were carried out with Xaar, MicroFab and Spectra Dimatix print heads and with solutions of polystyrene in diethyl phthalate as model fluids. These results are compared with
predictions from recent numerical codes developed by collaborators in the University of Leeds, and from simple models for drop-on-demand fluid jetting resulting from physical law
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Jetting, In-Nozzle Meniscus Motion and Nozzle-Plate Flooding in An Industrial Drop-on-Demand Print Head
Get PDFThe state of the ink film at and near the nozzles of a drop-ondemand(DoD) print head during jetting has a direct impact on
printing performance and reliability. We have developed highspeed imaging apparatus and analytical techniques to investigate
the ink film dynamics on an industrial print head nozzle-plate in real-time. In addition to a direct correlation between the jet
emergence velocity and drive voltage, drive-dependent variations in the oscillation of the ink meniscus in adjacent nozzles were also observed. Using a ray-tracing model to analyze the meniscus shape, the meniscus oscillations for both printing and nonprinting nozzles were found to be complex and involve elements such as pre-oscillation and high-order surface waves. The flooding of non-firing nozzles, deliberately caused by the application of maximum drive voltage to a neighboring nozzle, has been recorded and analyzed dynamically. The build-up of fluid in an annulus around the nozzle (flooding rate) has been characterized and compared with models for the net ink flow
through the nozzle
[Pen and Ink Drawings 01]
No full textSmall, abstract ink drawing.Tiff file: 850x775 pixels, 1.88 Mb; Display: jpeg, 204x186 pixels, 72dp
[Pen and Ink Drawings 07]
No full textSmall, abstract ink drawingTiff file: 1131x895 pixels, 2.9 Mb; Display: jpeg, 271x215 pixels, 72dp
[Pen and Ink Drawings 02]
No full textSmall, abstract ink drawingTiff file: 1082x800 pixels, 2.48 Mb; Display: jpeg, 206x192 pixels, 72dp
[Pen and Ink Drawings 03]
No full textSmall, abstract ink drawingTiff file: 803x972 pixels, 2.23 Mb; Display: jpeg, 193x233 pixels, 72dp
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