Inkjet Ink Research Articles

Wicking process of penetrants and inkjet inks on printing media

In this study, the dynamics of liquid capillary wicking (known as absorption, penetration, or imbibition) is discussed for a penetrant of an inkjet ink and commercial magenta inks. Different concentrations of penetrants on various printing media were tested, as well as magenta inks from HP and Canon. Penetrants are very efficient to wick inks on printing media and to reach maximum wicking area fast. The wicking areas of the penetrant solutions on test substrates are much lager than DI water. Since commercial ink contains 2 - 5% of penetrants, maximum areas of inks are larger than water and smaller than penetrant solutions. Alkylene glycol type penetrants such as Diethylene glycol monobutyl ether (DEGMBE), Diethylene glycol diethyl ether (DEGDEE) are to show large maximum wicking area and fast wicking rate. Alcohol type penetrants including Ethyl alcohol (EtOH) and Isopropyl alcohol (IPA) indicate fast drying rate at 100 and 50% concentration; however, drying rate of both alcohol type and alkylene glycol type penetrants at low concentrations are close to drying rate of water. Alkylene glycol type penetrants show less effects of concentration on wicking ratio, while concentrations of alcohol type penetrants greatly affects to absorption.

Test Methods of Humidity Fastness of Inkjet Printing Materials

Humidity fastness is an important attribute for inkjet printing materials. The test methods of humidity induced color change and loss of line quality are presently discussed in the ISO/TC42/WG5, where a method using checkerboard pattern as the test target is proposed for the quantitative estimation. In this study, we assessed the effectiveness of the method investigating the correspondence between the checkerboard measurement to the psychophysical evaluation, where we carried out extensive tests with a wide range of commercially available inkjet inks and media. At the same time, we reviewed test conditions, such as temperature, humidity and duration, in order to determine the appropriate standard test method as the ISO.

Silica Properties for Matte-Coated Media for Pigment Based Inks

Pigment-based inks are widely used in applications where long-term stability is of great importance. Choosing the ink-jet ink type is only one step in creating the optimal ink-jet printed product. The media must work synergistically with the ink and printer to obtain the optimum printed product. Formulators of the media must choose the proper materials for the ink receptive coatings to ensure outstanding performance. Silicas are one of the top-performing materials used by formulators to achieve quick dry times and excellent print quality. This paper examines the influence of silica properties on the performance of media printed by pigment based ink jet inks.

Approach for detecting localization of inkjet ink components using dynamic-SIMS analysis

Organic compounds having high boiling points included in inkjet inks remain in the printed media after printing. It has been said that these residual organic compounds influenced the fastness of pigment ink prints, but details of the analytical methods have not been reported, yet. In this paper, a new analytical method was applied for detecting localization of those organic compounds in inkjet prints after printing. Glycerin was chosen as a typical example of those organic compounds. To analyze the position within the printed paper, deuterated glycerin was formulated in the ink as a probe and dynamic Secondary Ion Mass Spectroscopy was applied to detect the deuterium peak in the whole printed paper thickness. It was found that glycerin remained in the range from the bottom of the pigment ink layer to the pigment coating layer of the printed media. This peak was sufficiently detectable for at least 7 days after printing. The maximum peak of residual glycerin was located at the surface of the coating layer of paper.

Retention and Redistribution of Ink-Jet Ink Components in Printed Media

Retention and Redistribution of Ink-Jet Ink Components in Printed Media

Alleviating Ink-Jet Mottle and Strike-Through in Uncoated Fine Paper

A study examined the causes of mottle and strike-through on ink-jet printed uncoated copy paper. Mottle results from the free movement of ink on the paper surface leading to uneven ink distribution. Strike-through occurs when free ink on the surface of paper finds a defect on the surface and then funnels into and through the defect to the back side of the paper. Mottle and strike-through were quantified with a stochastic analysis method using Verity IA software. Based on the mechanism of mottle and strike-through a study was made of paper additives that would either reduce free ink or overcome surface defects. Absorbents, adsorbents, and mordents reduce mottle and strike-through. In addition, the study identified several additives that changed how paper absorbed ink-jet ink. The additives very effectively reduced the print problems. The methods of reducing mottle and strike-through can be additive as seen in recently developed surface sizing agents.

Micro-sizing degree as a property of ink-jet media printability

As well as supreme image quality realized by specialized paper, industrial and office printing markets demand uncoated general papers compatible with both offset printing and non-impact printing. The present work aims at clarifying the behavior of a micro-liquid droplet of water-based ink-jet inks or simply water absorbed into uncoated paper. In the experiment, laboratory handsheets were prepared by adding alkyl ketene dimmer (AKD) as a sizing agent at different levels of water repellency; none, 0.05, 0.10 and 0.20 % on dry pulp mass. The landing action and the absorption into paper of micro-droplets of water ejected from an ink-jet head were recorded by the microscopic high-speed video camera system every millisecond. The period of time between the landing and the completion of absorption was defined as “micro-sizing degree”. The micro-sizing degree was approximately 2 to 3 ms up to 0.10 % AKD addition. It is lower than that of commercial silica-coated ink-jet papers which was approximately 8 ms although silica-coated papers are known to absorb water very quickly. However, the micro-sizing degree was approximately 45 ms for the handsheets of 0.20 % AKD addition. This result implies that the water-repellency by AKD is distributed over fiber surfaces so homogeneously that micro-water droplets of diameters of as small as a few micrometers are absorbed stably at similar rates.

Pigments & Dispersions for Energy Curable Inkjet Inks

Surface-treated pigments are described. Surface treatment allows for ease of disperse-ability of pigments into monomers that are commonly utilized in energy-curable inkjet inks. The resulting pigment dispersions have low viscosity and high pigment loading. Inks made from these dispersions have properties of small particle size, high filter rates, low viscosity and high chroma. The surface-treated pigments facilitate excellent stability of ink viscosity and filterability after accelerated oven-aging. Surface treatments have a chemical similarity but are optimized for each pigment. The range covers carbon black, phthalocyanine blue, arylide yellow, nickel azo yellow, and quinacridone magenta.

Printability of Ink-jet Printing on Surface-treated Nonwoven Fabrics

The micro scale distribution of ink-jet inks on surface-treated nonwoven synthetic fiber sheets was evaluated with a confocal laser scanning microscope (CLSM) in order to characterize the ink-setting on the surface of the media.Nonwoven synthetic fiber sheets made from hydrophilic or hydrophobic fibers were prepared. Surface characteristics of the nonwoven sheets varied with corona treatment. The corona-treated application on nonwoven sheets was investigated in order to improve the wettability of the surface of the nonwoven sheets. The corona-treated nonwoven sheets were printed using dye type and pigment type ink-jet printers and the distribution of the magenta inks on the sheets were observed using CLSM.The micro scale distribution of the inks on the surface-treated nonwoven sheets could be estimated by CLSM nondestructively. Nearly all of the dye type inks did not fix on the hydrophobic nonwoven sheets. After applying corona treatment, the sheet surfaces became more hydrophilic, resulting in an increase of hydrophilic functional groups with the fiber surfaces and the ink set on the sheets. However, the process of ink-setting on the hydrophobic sheets differed with the type of hydrophobic fibers. It was observed that the microstructure of one kind of hydrophobic fiber changed under the corona treatment and more ink fixed on the surface of the fibers. This suggests that not only chemical but also micro structural changes of the sheet surfaces greatly affect the ink-setting on the sheets. In the case of the pigment type ink, more ink was able to set on the hydrophobic sheets compared to the dye type ink.It was concluded that the wettability and the surface topography of the media had a great effect on the setting of the ink-jet inks and the printing quality. Higher quality ink-jet printing on nonwoven sheets is possible through suitable surface-treatment of the sheet. The CLSM method could be used to evaluate the printability of the media such as nonwoven synthetic fiber sheets.

Photocurable inkjet ink for printing on metallic and plastic substrates

A novel vinyl ether monomer was employed to improve curing properties of photocurable inkjet ink. A cationic polymerization system was used and the improved curing properties using a novel vinyl ether monomer with cyclic ether compounds were demonstrated. The cured UV ink film showed good adhesion on metallic substrates such as stainless steel, copper, aluminum and also plastic substrates. The stability of pigment dispersion in the ink was improved by controlling zeta-potential of the ink. The higher zeta-potential value resulted in stable particle size of the pigment and viscosity of the ink.

Preparation of waterborne nanoscale pigment dispersions for formulations of inkjet inks

Textiles Inkjet printing as a new dyeing method with higher resolution, lower pollution and shorter run length has attracted more and more people's attention. Pigment inks have become one of the main colorant materials in this technology for its excellent light fastness and suitable to all sorts of textiles. However most of organic pigments with low polarity are hard to be wetted and dispersed in aqueous media, therefore the organic pigments should be modified before their application. In this paper, waterborne nanoscale pigment dispersion including Copper Phthalocyanine blue (P.B.15:3), Quinacridone red pigment (P.R.122), and Monoazo yellow pigment (P.Y.14) have been prepared by phase separation method and direct milling with dispersants method respectively. The properties (stability, particle size and apparent viscosity) of dispersion which prepared by different method were compared. The results show that the pigment dispersion has higher stability to alcohols, temperature and storage, and also lower viscosity; the phase separation method was more suitable to preparation of pigment dispersion for formulations of inkjet inks than direct milling with dispersants method; TEM photo indicated that the pigment particles were uniformly distributed in aqueous media and the XRD curves indicated that the pigment crystal was not changed after encapsulation by phase separation method.

Nanocolorants: A novel class of colorants, the preparation and performance characterization

Anthraquinone-based solvent red, yellow (or green), and blue dyes used as essential ingredients were completely dissolved in styrene miniemulsion system, and a set of nanocolorants were successfully prepared by using a modified miniemulsion polymerization process. In architecture, the obtained nanocolorants belong to a class of nanocomposite entities, in which a fraction of dye molecules are attached with crosslinked macromolecular chains and more dye being embedded in the interior of crosslinked polymer owed to the high hydrophobicity of dyes and phase separation between dye and polymer during the polymerization process. The performance characterization of the obtained nanocolorants indicated that they exhibited excellent chromatic properties attributed to the nanoscale effects of homogeneous nanocolorants, and really achieved superior migration fastness, light fastness, thermal stability, and good processibility. These nanocolorants are very applicable for aqueous ink-jet inks, color resistance, high-performance coloration for polymers, and for electrophotographic toners.

Preparation of Organic dye-Inorganic Silica Hybrid Pigment and It's Application for Inkjet Dispersion Ink

Studies were performed on preparation of organic-inorganic hybrid silica dye in a dispersing ink system. The silica was subjected to surface modification using 3-aminopropyltrimethoxysilane (APTMS) in order to promote the chemical reactivity of the raw silica. On the surfaces of the aminosilane-functionalised silica, red vinylsulfone-containing azo dye was adsorbed. The dye was found to have chemically reacted with the aminosilane-grafted silica surface, which was proven by FT-IR spectra. Studies on morphology and microstructure were performed employing scanning electron microscopy. The SEM micrographs and particle size distributions showed that a homogeneous pigment can be obtained employing silica as a core. Particle size distribution was also examined using the technique of dynamic light scattering. The ensuing pigment was subjected to various physicochemical evaluation such as inkjet property, storage stability, color change as inkjet ink using printer, spectrophotometric, microscopic techniques. Studies on hybrid dyes from the silica surface demonstrated that, in general, stable pigments for inkjet dispersion ink were obtained.

A Simple MicroThermal Desorption Device

A new method for thermal desorption of small samples is presented. The method uses a solid phase microextraction (SPME) holder with the fiber removed. The sample-for example, an ink sample on paper-is simply placed inside the needle of the holder, where normally an SPME fiber is positioned. The thermal desorption is then performed on any kind of gas chromatograph in a manner similar to that for SPME analysis. The needle of the SPME holder penetrates the injector septum; the temperature of the thermal desorption is simply the temperature of the injector. No solvents or liquid nitrogen cooling are used. The paper sample is kept inside the holder needle during the analysis. After the analysis is completed, the sample is removed from the needle by pushing forward the steel wire inside the needle in the way normally used to perform sampling with the SPME fiber. The desorbed compounds were analyzed by gas chromatography with a flame ionization detector or by gas chromatography-mass spectrometry. The optimum temperature for desorption of ink samples on paper was 200 degrees C. The influence of the paper matrix is negligible at that temperature. Laboratories lacking the commercial device for thermal desorption can use this cheap device for the analysis of, for example, writing ink, printing ink, and inkjet ink samples on paper. Other types of samples can be investigated but the size of samples suitable for analysis is limited.

光沢に優れる顔料インクジェットインク(PX-Gインク)の開発

光沢に優れる顔料インクジェットインク(PX-Gインク)の開発

Preparation and application of nanoscale microemulsion as binder for fabric inkjet printing

To obtain a nanoscale binder suitable for pigment-based inkjet ink printing on fabrics, a polymer microemulsion with a high content of soft monomer of butyl acrylate (BA) was synthesized via a modified microemulsion polymerization method, where N-methylolacrylamide (NMA) served as the cross-linking monomer and monododecyl maleate (MDM) as the copolymerizable surfactant. The effects of the functional monomers (NMA, MDM), the weight ratios of monomers, and the solid contents on the microemulsion properties were investigated by TEM, DSC, particle size analyzing, and fabric inkjet printing. The results indicated that the microemulsion had a number-average particle diameter less than 50 nm and with narrow particle size distribution. It was also found that the glass transition temperatures ( T g) of the film formed from the microemulsion could be lower than −30 °C. Fabric inkjet printing application of the pigment-based inks formulated with the as-considered optimum microemulsion as a binder and commercial pigment dispersions demonstrated excellent printability of the inks, and good colour fastnesses and softness of the printed fabrics.

Liquid–paper interactions during liquid drop impact and recoil on paper surfaces

The spreading and recoiling of water drops on several flat and macroscopically smooth model surfaces and on sized paper surfaces were studied over a range of drop impaction velocities using a high-speed CCD camera. The water drop spreading and recoiling results on several model hydrophobic and hydrophilic surfaces were found to be in agreement with observations reported in the literature. The maximum drop spreading diameter for those model surfaces at impact was found to be dependent upon the initial drop kinetic energy and the degree of hydrophobicity/hydrophilicity of the surface. The extent of the maximum drop recoiling was found to be much weaker for hydrophilic substrates than for hydrophobic substrates. Sized papers, however, showed an interesting switch of behaviour in the process of water drop impaction. They behave like a hydrophobic substrate when a water drop impacts on it, but like a hydrophilic substrate when water drop recoils. Although the contact angle between water and hydrophilic or hydrophobic non-porous surfaces changes from advancing to receding as reported in literature, the change of contact angle during water impact on paper surface is unique in that the level of sizing was found to have a smaller than expected influence on the degree of recoil. Atomic force microscopy (AFM) was used to probe fibres on a sized filter paper surface under water. The AFM data showed that water interacted strongly with the fibre even though the paper was heavily sized. Implications of this phenomenon were discussed in the context of inkjet print quality and of the surface conditions of sized papers. Results of this study are very useful in the understanding of inkjet ink droplet impaction on paper surfaces which sets the initial condition for ink penetration into paper after impaction.

Analysis of Non-Newtonian Liquids Using a Microfluidic Capillary Viscometer

We have used a self-calibrating microfabricated capillary viscometer to analyze non-Newtonian power law fluids. The capillary viscometer can generate a wide range of shear rates during a single experimental run enabling quick and accurate analysis of non-Newtonian liquids. The measurement of viscosity is based on monitoring the capillary pressure-driven movement of fluid sample whose mean velocity and, therefore, shear rate varies with time. The device has been successfully tested for accuracy and robustness with dilute as well as semidilute solutions of flexible elastic polymers including poly(ethylene oxide) and hydrolyzed polyacrylamide to an aqueous solution of a stiff rodlike polymer molecule of xanthan gum, a popular emulsifier and food thickener, as well as with ink-jet printing inks. Viscosities in the range of 1-600 cP were measured, and shear rates varying from 5 to 1000 s(-1) have been obtained on the microfabricated viscometer with the current geometry and channel dimensions. The total measurement time varied between 2 and 8 min and less than 1 microL of sample volume was required. Such a microfabricated capillary viscometer would have possible applications in quality control and manufacturing where rapid and repeated measurements need to be made using limited sample volume.

Basic Concepts of Stability and Instability in Water Based Inkjet Pigment Dispersions

We shall review the main concepts of pigment dispersion stability and apply them to derive practical rules regarding inkjet ink both for OEM and refillers useful in general, but particularly for SOHO printers.We shall also propose two conceptual sketches to understand the stabilization phenomena.

Pigment Surface Modification via Nucleophilic Treating Agents

Employing chemical reactions that modify particle surfaces to impart desirable physical-chemical properties has enjoyed enormous commercial success. One example is the surface modification of pigment particles for inkjet inks. As the applications of pigmented inkjet inks continue to grow, there is a need to modify a wider range of pigment types. The existence of many classes of pigments with various functional groups has presented challenges for the development of a general chemistry that can react with any pigments. As a result, inventing new ways of modifying pigment surfaces is important. In this report, treating agents having nucleophilic groups were used to modify Pigment Green 36 (PG36). When PG36 was modified with nucleophiles bearing water-soluble groups, pigment particles became water dispersible. Dispersions showed excellent colloidal stability and the color properties of PG36 have not been affected. This paper will also discuss the versatility of this chemistry for introducing a wide range of functional groups onto pigment particles that possess leaving groups.