UV Inkjet Research Articles

3D Printing of Topographic Map Based on UV Ink-Jet Printer

Traditional maps have the characteristics of high and low terrain, using the method of contour. Although contour map can express relief form, the stereo sense is not intuitive. In this paper, according to the characteristics of UV inkjet printer, the designed test pattern was printed, ink layer thickness of different colors was measured to establish a quantitative relationship between ink thickness and ink layers. The contour map of Taiwan was chosen, in graphics processing software, to extract the contour vector image according to its elevation. According to the relationship between ink thickness and ink layers, the corresponding relation table between the actual elevation and ink layers was established. Layered corresponding table was designed, according to the contour of layered principle. The experimental result shows that the color topographic map with stereoscopic effect can be obtained, through UV ink-jet printer.

Properties and printability of compression moulded recycled polyethylene

The goal of the research was the determination of the properties and printability of polymeric materials made from the recycled polymers, low-density polyethylene (LDPE) and high-density polyethylene (HDPE). From the primary (virgin) polymers and secondary (recycled) polymers that were obtained from the separately collected fractions of waste packaging, compression moulded plates were produced. The tensile properties of 1mm and 2mm thin plates were correlated with some structural characteristics: melting point, melting enthalpy and crystallinity degree. It was determined that the recycling process changes the melting behaviour, lowers the crystallinity and to some extent influences the tensile properties of plates. LDPE and HDPE compression moulded plates were printed with the UV inks on the large format digital UV inkjet printer Océ Arizona. To investigate the printability of plates made from the recycled materials some of their surface properties were determined. Higher optical density, area of ink coverage and dot gain of the printed HDPE plates compared to the LDPE plates are the consequence of higher roughness, higher surface energy with prevailing part of the polar component. By adding 4% of coloured master batch to the recycled polymer at moulding, the uniformity of colour is improved leading to the higher print quality. The results have shown that the digital UV inkjet printing technique could be applied for printing recycled polyethylene plastic materials, used for disposable low cost packaging products.

Development of Printing Method to Produce High-glossy Images with UV Inkjet Printer

While UV-curable inkjet printers have come into wide use, these printing systems have a few problems to be solved. We took notice that the printed images showed relatively low gloss. The decrease in gloss is known to be caused by the fact that UV-curable ink changes into solid before leveling off under irradiation of UV light. We have been trying to develop the new application of UV-curable inkjet printing to obtain high glossy images on the surface of various articles. We had already presented a prototype as one of such trials at ICJ2012, the annual conference of the Imaging Society of Japan in 2012. The process was called DVT which was the decompression transfer printing process with a UV-curable inkjet printer and a vacuum chamber. The DVT had some problems such as low image quality and troublesome process with manual operation. The first improved process which was called DVT-I was proposed at ICJ2013 held in Tokyo last June. However there still remained a few problems, so that we have continued our study and then developed an automated machine in this study. High image gloss has been obtained by excluding air bubbles during the decompression process. Thus we have been able to create products with high quality and glossy images on the surface of various articles.

Research on the Relationship between Properties of Printing Paper and UV Inkjet Printing Quality

As an environmental printing method, UV inkjet printing is becoming a hot research topic and has great prospects for development. The purpose of this paper was to integrate theory with practice to analyze the relationship between printing paper and UV inkjet printing quality. This could make press worker determinate rationally printing paper and improve the printing quality. In this paper, kinds of paper surface characteristic (including whiteness, glossiness, roughness, Permeability, absorbent) were measured. Printing tone and color reproduction results of these papers were experimented. Different prints parameters were tested with saturation, hue error, gray scale and coloration efficiency. Data of the paper parameters and prints parameters were calculated separately by Principal Components Analysis (PCA) with software. Then, the equation between paper parameters and paper quality synthetic value was obtained on the basis of the tested data. The equation between prints parameters and prints quality synthetic value was obtained in the same way. Linear regression was used to find the correlation between line combination of print quality synthetic value(y-axis) and paper quality synthetic value(x-axis). Paper printability prediction equation is derived according to the curve. It was shown that the results can provide valuable reference for the evaluation of the quality of printing papers and improving color reproduction, and can be used as one of the basis to guide the production.

Color Gamut of UV Wide-Format Inkjet Printing on Special Substrates

UV Inkjet Printing has demonstrated extraordinary potential in printing technology around the globe in recent years. Other than its environment-friendly trait, UV Inkjet Printing can also be applied to various printing materials due to its wide range of application. Comparing to the low-price competition invoked by paper-based printing, it achieves high added-value results from its output. While international market’s perspective on inkjet printing remains positive, most printing press in Taiwan still have doubts for the technology. In recent years, there has been a considerable growth in importing UV Width Inkjet printers in Taiwan domestically. However, working personnel in Taiwan are inexperienced in dealing with new equipment and wider selection of printing materials, therefore the issue of printers adapting to their diverse printing materials. This study will examine the five combinations of UV printer and printing materials that are common in Taiwan (brands of printers, serial number of the sprinkler head, and brands of printing ink) and three specific high-value printing substrates (glass, acrylic and melamine plywood). Through the printing experiment, the color gamut of printing materials will be re-examined. The goal of the study is to establish a standard for UV printing’s application in decoration materials, so as to provide reference for future development.

The Effect of UV Inkjet Ink’s Performance on the Line Printing Quality

In order to smoothly jet from the nozzle, UV inkjet ink need to meet certain performance requirements, the surface tension of ink has certain effect on the formation and the flight path of ink droplet, directly affect the final printing quality. The black UV inkjet ink samples were prepared by selecting 5 kinds of surfactants, the surface tension was tested. The effect of the surface tension on ink droplet status and final line printing quality were studied. The results show that the surface tension of ink is different, the ink droplet status is different; the surface tension of ink have certain effect on the line width and density of lines, and have little impact on the roughness and contrast of lines.

The Study on Color Print Quality Attributes of In-Mold Roller Using Digital Inkjet Printing

The In-Mold Roller is a revolutionary printing process by which objects are 3D decorated. The products decorated by In-Mold Roller are protected from water and fading. These kinds of decorations strongly increase the beauty, desirability and value of the objects. The In-Mold Roller is now using either of gravure printing and screen printing to print PET film. However, there are some problems with these two techniques. This research is to investigate the potential use of combining In-Mold Roller with digital inkjet printing in 3D decoration, e.g. in personalized printing services. The study results found show that digital inkjet printing to the PET film and then transfer to the ABS, the solid ink densities (SIDs) of primaries would increase. The tone values increases (TVIs) from highlight and middle (around 0~60%) were generally higher than those in shadows. The shapes and sizes of color gamut were also varied according to different kinds of digital UV inkjet printing processes. Moreover, after transferred, the color gamut became smaller.

UV Inkjet Inks with Improved Stray Light Resistance

Energy curable inkjet inks are susceptible to build up of cured material at the nozzle where ink is ejected, which leads to jet deviation and ultimately lost jets. This causes a reduction in image quality and the need to replace the printhead. Traditional stabilizers do not reduce the susceptibility of energy curable inkjet inks to stray light or if they do, cure is compromised. It has been discovered that nitroxyl stabilizers will significantly reduce the build up of cured ink caused by exposure to low levels of UV light from stray light sources without compromising cure speed. In this paper a new test method for assessing the stray light resistance of energy curable inkjet inks is detailed. The major types of stabilizers are described and their effect on stray light resistance and cure for UV curable inkjet inks is determined.

Study on the Curing Kinetics of UV-Curable Inkjet Ink

In order to make different UV curing inkjet ink system and test the relationship between the dynamic elastic modulus and UV curing time, the same monomer and pre-polymer were mixed in different proportions, and different functional monomers and pre-polymer were mixed. The results show that the larger the proportion of the pre-polymer and the greater the number of monomer functional groups, the shorter the induction period of the UV curing of UV inkjet ink system and the faster the UV curing rate. Then, the UV curing kinetics of UV inkjet inks was analyzed preliminarily.

Optical and Color Stability of Aged Specialty Papers and Ultraviolet Cured Ink Jet Prints

The present study deals with the optical and color stability of aged specialty papers and ultraviolet cured (UV) ink jet prints. As paper substrates, a fiber synthetic paper and two types of lignin-free papers with included security elements were used. Prints of CMYK color fields using UV Curable Inks were made using a UV ink jet printer, Océ Arizona 250® GT. Samples of papers and UV ink jet prints were artificially aged using standard techniques of accelerated aging, such as moist heat (80°C and 65% RH), dry heat (105°C) and treatment with the a xenon arc lamp (35°C CT, 50°C BST, 35% RH). Aging was performed for periods of 1, 2, 3, 6, and 12 days. In this study, optical properties of untreated and treated paper substrates such as the whiteness and yellowness index and color differences between untreated and treated UV ink jet prints were followed. The tested paper substrates behaved differently. The fiber synthetic paper was more stable than both lignin-free cellulose papers. Some color differences during accelerated aging were observed in prints. The effect depends on the particular ink and type of accelerated aging. On average, dry heat treatment and treatment with the xenon arc lamp showed greater impact on CMYK prints than moist heat treatment. The most stable among the prints was the black ink.

Improvement of image quality in single pass UV inkjet printing

This report introduces factors to improve image quality obtained by single pass inkjet printing with UV ink. As reported at NIP24, this study is made with 600 dpi single pass inkjet printheads, capable of single pass printing at 847 mm/s in 108 mm print swath. In the former study, authors concluded that image quality could be sharper by higher pass speed in case of single pass inkjet printing, since amount of ink flow on a media surface before curing can be restricted. However, it was revealed that fast printing speed could suffer image quality with unevenness of image surface created with thick ink layer. In order to solve the problem, approaches are made from both ink and printhead properties. Firstly, static surface tension of UV ink is lowered from 30 to 22-25 mN/m. It is expected to maintain enough dot gain with smaller drop volume, which makes ink layer thinner. Also, color density of ink has to be enhanced to keep equivalent color range with thinner layer. Secondly, printhead is modified in terms of optimum drop volume range from 5 – 19 to 4 – 12 pl for modified ink. Also, drop placement accuracy is improved by increasing drop velocity. As a result, thickness of ink layer is reduced from 12.7 microns to less than 9.6 microns on a gloss coat media. As a result, appearance of color images are much improved. It is achieved UV ink named AGORA G1 developed by Agfa Graphics.

Evaluation of printability on synthetic papers printed by UV ink jet

Evaluation of printability on synthetic papers printed by UV ink jet

Practical Application of UV-LED Curing Technology to UV Inkjet

UV-LED curing systems have started to play a larger role in many UV curing applications - including wide format and single pass UV inkjet – and their application and adoption will likely continue to accelerate over the next several years.Adoption is increasing based on the wider availability of suitable UV-LED inkjet ink formulations. The inherent advantages of UV-LED technology - in terms of lifetime, consistency of output, instant on/off and lower heat production, as well as the possibility for systems that are smaller and more robust when compared to existing traditional lamp solution - makes it particularly attractive for UV Inkjet applications.Just like all new technologies there are important differences, distinctions and choices that must be made if a successful implementation is to be achieved. UV-LED curing systems are not the same as traditional mercury vapor lamp systems and the issues of required irradiance/power output, measurement of irradiance/power and understanding of the effects and availability of wavelengths available today in UV-LED are key in making appropriate decisions about the suitability of the technology. These and other system level considerations will be discussed and the paper will outline several successful implementations of UV-LED for inkjet that are currently in the public domain.The paper will also outline the challenges and will share some data and insight into the practical application and efficacy of newer generation UV-LED systems when applied to optimized inks sets for UV Inkjet applications.

Reactive Inkjet Formulations - Curing By Electron Beam

Ultraviolet light (UV) reactive inkjet printing has become well known as a reliable printing method for graphic display printed products. Single pass UV-curing inkjet printing systems are now becoming technically feasible, where sheets or a web are printed when passing under a static array of printheads. An area of interest for UV inkjet is indirect contact food packaging, but UV inkjet inks are less than ideal.The energy of a typical UV photon is below the chemical bond energy of acrylate monomers; this means that the curing reaction cannot be initiated without the presence of a photoinitiator. As the energy of electron beam (EB) electrons easily exceeds the bond energy of acrylate monomers, they will initiate cure without added photoinitiator. Problems of migration, taint, and odour associated with uncured photoinitiator and photoinitiator fragments are then eliminated.EB curing of reactive inks is well known for offset and flexography indirect food packaging printing, as there is potential for low migration. There is therefore a strong driver to extend this curing process to ink jet systems.In this paper the concept of combining EB as the cure method and inkjet as the printing method is discussed, with the objective of printing indirect contact food packaging. The paper focuses on aspects of the formulation of photoinitiator free reactive inkjet inks, including monomer selection and type and the effect this has on migration levels when cured by an electron beam process.

Use of Confocal Microscopy as a Nondestructive Method in the Study of Ink Jet Dot Formation

The formation of the printing ink dot on the substrate is the final and the most critical phase in the printing process. The ink distribution on the printing surface and the drying mechanism depend on ink characteristics as well as on many other factors, for example, surface energy, roughness, sizing, and porosity. Suitable dot gain and high circularity (near unity) of printed dots predict the final print quality. High deviation from ideal circularity could cause undesired phenomena like wicking and bleeding. The aim of the present study is to determine ink dot formation by three different microscopic methods, optical microscopy (OM), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). The main goal of the authors research was to evaluate the applicability of CLSM as a nondestructive method for three-dimensional visualization in the analysis of ink dot formation on UV ink jet prints. To validate the feasibility of such means in a three-dimensional context, the images obtained are compared to those obtained by traditional two-dimensional imaging systems such as OM and SEM. The authors show that the CLSM produces a replica of the cross-sectioned dot profile as seen in SEM. This means that the CLSM technique can be used to rapidly assess the dot profile without physical sectioning.

Evaluation of the Pigment Dispersion of UV-Curable Inkjet Ink Using UV Absorption Spectrum

With the formulation experiment to design the UV inkjet ink of different pigment/binder ratios, UV inkjet ink samples of different dispersions are prepared. The size and distribution of pigment particles and UV absorption spectrum of the samples are then tested. The result indicates that: the pigment/binder ratio has a great impact on the dispersion of the UV inkjet ink, when the ratio is 2:1, the ink sample can obtain good dispersion; dispersion of the pigment particles affects the intensity of UV absorption of the ink system. The absorption spectrum has a strong dependence with the dispersion of ink. With the decreasing of the pigment particle size, the UV absorption intensity of the ink system increases. The main innovation of this study lies in the establishment of evaluating particle's dispersion according to the change of UV absorption spectrum of the ink system.

Techniques of Optimizing the UV Curing Process for Ink Jet Deposition of “Opaque” Materials

UV Ink Jet is rapidly gaining applications and uses in industrial markets requiring print-on-demand, variable information, and short-run graphics on an increasing variety of substrates. The performance properties of UV-cured materials are substantially affected by the lamp systems that are used to cure them. The development of the intended physical properties of a UV-cured ink can depend on how well these lamp factors are designed and managed, and how well the UV exposure is designed for the specific printer and print head arrangement. A number of variables of a lamp system, which can be designed or selected to produce the most efficient result, are discussed. Ink design, in terms of spectral absorbance and “optical thickness,” is fundamental to this relationship. The four key factors of UV exposure are: UV irradiance (or intensity), spectral distribution (wavelengths) of UV, total UV energy, and infra-red radiation. UV inks will exhibit very different response to peak irradiance or energy, and to different UV spectra. The ability to identify the various lamp characteristics and match them to the optical properties of the curable material, widens the range in which UV curing is a more efficient production process.

Alternative UV Radiometry and Process Verification for UV Ink Jet Printing

Alternative UV Radiometry and Process Verification for UV Ink Jet Printing

The Practical Relevance of Solid State UV LED's for the Curing of Inks in Contemporary Ink Jet Applications

The use of solid-state UV emitting LED technology as a light source for the curing of UV inkjet inks has received much “hype” over the past 2 years. UV LED's offer apparent significant advantages in terms of durability; consistency; low power consumption; low heat emission; and instant switching, and yet their uptake is almost insignificant in what is undoubtedly a buoyant and rapidly growing market.This is in the main due to the incompatibility of current chemistry formulations, in conjunction with other barriers such as economics and intellectual property issues.A key problem has been the belief that this technology could displace current UV light sources in existing applications thereby placing unrealistic expectations on this emerging technology, instead of looking at complimentary or new applications where UV LED's may offer significant advantages.At present UV Led's cannot generate sufficient spread of wavelength nor until recently sufficient energy to fully cure current ink formulations, (however they can readily partially cure or “freeze” / “pin” such inks). More importantly LED's remain a more expensive solution in a highly cost sensitive industry.Far better to look at practical and realistic applications for this technology, applications that cannot be readily achieved with traditional UV light sources. Some such examples of are:• Curing of inks on Glass (where only partial cure is necessary followed by a thermal post-cure• Curing between print-heads in a linear high resolution print engine• 3 D modeling systems• Electronics manufacturing• “Pinning” cure on static web fed print engines• Curing of special resins in fat panel display manufacturing or other similar product assembly.In conclusion, Solid state LED light sources will not displace current UV technology, but used intelligently will compliment it. We can expect to see a slow emergence of new chemistries especially formulated for UV LED's combined with an increase in the usable output from LED devices and a gradual easing of the current prohibitive costs.

Techniques of Optimizing the UV Ink Jet Curing Process

UV Ink Jet is rapidly gaining applications and uses in industrial markets requiring print-on-demand, variable information, and short-run graphics on an increasing variety of substrates. The performance properties of UV-cured materials are substantially affected by the lamp systems that are used to cure them. The development of the intended physical properties of a UV-cured ink can depend on how well these lamp factors are designed and managed, and how well the UV exposure is designed for the specific printer and print head arrangement. A number of variables of a lamp system, which can be designed or selected to produce the most efficient result, are discussed. Ink design, in terms of spectral absorbance and “optical thickness,” is fundamental to this relationship. The four key factors of UV exposure are: UV irradiance (or intensity), spectral distribution (wavelengths) of UV, total UV energy, and infra-red radiation. UV inks will exhibit very different response to peak irradiance or energy, and to different UV spectra. The ability to identify the various lamp characteristics and match them to the optical properties of the curable material, widens the range in which UV curing is a more efficient production process.