Types Of Inks Research Articles

Research on the types and toxicity of VOCs released from solvent-based inks in high temperature environment

ABSTRACT During the utilization, blending, transportation, and storage, a significant amount of volatile organic compounds (VOCs) are released from inks, posing risks to both human health and the ecological environment. This study sought to identify the types and structures of VOCs released from four types of solvent-based inks (referred to as CAB, PVB, AKR, and Rs inks) in high-temperature settings and to assess the bioaccumulation factors, developmental toxicity, and acute toxicity of these released VOCs. The findings revealed that all tested inks released substantial amounts of VOCs in high-temperature environments. CAB and PVB inks released fewer types of VOCs with relatively smaller molecular weights, primarily with carboxylic acid groups and hydroxyl groups, while AKR and Rs inks released more types of VOCs with larger molecular weights, including polycyclic aromatic hydrocarbons. Toxicity analysis indicated that although the primary VOCs released from CAB and PVB ink displayed some developmental toxicity, their bioaccumulation factors were below 100. The principal VOCs from AKR ink did not exhibit developmental toxicity. Conversely, the predominant VOCs from Rs ink not only demonstrated developmental toxicity but also had bioaccumulation factors exceeding 100. Additionally, the VOCs released from CAB, PVB, and AKR inks exhibited stronger acute toxicity to luminescent bacteria, while those from Rs ink showed greater acute toxicity to fish. These results offer a scientific foundation for the safe usage of inks and environmental conservation.

Determining the sequence of intersecting lines formed by laser printer toner and seal ink based on confocal Raman spectroscopy.

In the field of questioned document examination, determining the sequence of intersecting lines is still a technical challenge. This study aims to validate whether confocal Raman spectroscopy can determine the sequence of intersecting lines created by laser prints toner and seal ink through empirical research. The study collected 110 varieties of seal ink and 1074 test pages from 66 models of laser printers available in the Chinese market. Based on the Raman spectral characteristics of the seal ink and the microscopic morphology of the toner, 13 types of seal ink and three types of laser printers were selected for further analysis, producing 78 representative samples of intersecting lines. Confocal Raman spectroscopy was applied to the examination of these samples using a point-scanning mode for enhanced accuracy and efficiency. The experimental results demonstrate that confocal Raman spectroscopy can non-destructively and quickly examine the sequence of intersecting lines produced by laser printer toner and seal ink. Variations in toner forms result in differing levels of difficulty in resolving intersection problems, with the sequence of intersecting lines from toner-dense laser printers being the easiest to ascertain. In contrast, those from printers with porous and dispersed toner present a more significant challenge in examination. This study can be corroborated with other methods proposed, and more significantly, it lays the groundwork for addressing intersection problems related to other printing or writing instruments.

Dissipative Particle Dynamics of Nano-Alumina Agglomeration in UV-Curable Inks.

Ultraviolet (UV) ink is a primary type of ink used in additive manufacturing with 3D inkjet printing. However, ink aggregation presents a challenge in nano-inkjet printing, affecting the stability and quality of the printing fluid and potentially leading to the clogging of nanometer-sized nozzles. This paper utilizes a Dissipative Particle Dynamics (DPD) simulation to investigate the aggregation behavior of alumina in a blend of 1,6-Hexanediol diacrylate (HDDA) and Trimethylolpropane triacrylate (TMPTA). By analyzing the effects of solid content, polymer component ratios, and dispersant concentration on alumina aggregation, the optimal ink formulation was identified. Compared to traditional experimental methods, DPD simulations not only reduce experimental costs and time but also reveal particle aggregation mechanisms that are difficult to explore through experimental methods, providing a crucial theoretical basis for optimizing ink formulations. This study demonstrates that alumina ceramic ink achieves optimal performance with a solid content of 20%, an HDDA-to-TMPTA ratio of 4:1, and 9% oleic acid as a dispersant.

Optimization of the interfacial properties between mechanically and electrochemically treated aluminium and nano-modified coatings for printed outdoor applications

The aim of this research was to analyze the interfacial properties between the surfaces of mechanically and electrochemically treated aluminium substrates and the printed coatings modified by the addition of silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles. The nanoparticles were added to the printing inks in various concentrations with the scope to optimize the interface properties of the prints for outdoor applications. The surface, as well as the structural and mechanical properties of the printed coatings were evaluated. Various methods were employed to measure and analyze the surface and interfacial properties of aluminium and coatings. Surface microphotographs and the roughness of the treated aluminium substrates were examined, the surface free energy of the aluminium and the coatings as well as the adhesion properties were calculated, and the thickness and optical density of the coatings were measured. Considering that the treated aluminium samples prepared for this research had quite textured and different surfaces, the contact angles used for the calculation of surface free energy were calculated with and without Wenzel model to obtain detailed information about the interactions between the surface of aluminium samples and the printed modified coatings. The results showed that the type of treatment of aluminium substrates as well as the modification of the printing inks have a significant influence on the adhesion and surface properties of the coatings considered. Furthermore, the results demonstrated that the produced nano-modified coatings can be used as printed coatings or as customized primers for applying various types of inks and coatings.

A Long Wave-Infrared Miniatured Quantum Dot Spectrometer.

In this work, a long-wave infrared (LWIR) quantum dot (QD) spectrometer was constructed for the first time by integrating a 255-element HgSe QD filter array with an LWIR array detector. The filter array was fabricated using a combination inkjet printing strategy with eight types of T-dodecyl mercaptan-terminated HgSe QD inks. The stability and morphology of the QDs were improved by optimizing the purification methodology and ligand modification. Combined with the compressive-sensing-based least-squares linear regression (CS-LS) algorithm, the LWIR QD spectrometer achieved a spectral resolution of 5.4 cm-1 over a wide spectral range of 8 to 14 μm, enabling the detection of the chemical warfare agent simulant dimethyl methylphosphonate. This technology is expected to facilitate the development of smaller volumes and more accurate identification of various targets in the future. This paper offers an approach to fabricating low-cost LWIR spectrometers and promoting the scale-up applications of QD devices.

New screen-printed electrodes for Raman spectroelectrochemistry. Determination of p-aminosalicylic acid

BackgroundThe availability of new surface enhanced Raman scattering (SERS) substrates is essential to develop quantitative analytical methods. Electrochemistry is an easy, fast and reproducible methodology to prepare SERS substrates on screen-printed electrodes (SPEs). ResultsThis work proposes new SPEs based on a three-electrode system all made of silver. Using the same ink for the whole electrode system facilitates the fabrication process, reduces production costs, and leads to excellent analytical performance. The results showed that Raman enhancement depends strongly on the type of silver ink. To demonstrate the capabilities of the new electrodes developed, 4-aminosalicylic acid was determined in complex matrices and in the presence of strong interfering compounds such as salicylic acid and acetylsalicylic acid. The proposed analytical method is based on the electrochemical surface oxidation enhanced Raman scattering (EC-SOERS) strategy. AgCl nanocrystals are generated on the working electrode surface, which amplify the Raman signal of 4-aminosalicylic acid. Good figures of merit were obtained both in the absence and in the presence of the interfering compounds, achieving a correct estimation of a 4-aminosalicylic test sample in complex matrices. SignificanceThe new SPEs have been demonstrated to be very sensitive and reproducible which, together to the high specificity of the Raman signal, makes this methodology very attractive for chemical analysis.

Print Quality Analysis of Stone Paper and Coated Sticker Paper Used in Screen Printing

The sustainable use of natural resources is becoming an increasingly important issue today. Stone paper, produced as an alternative to cellulose-based paper from the forest, is rich in minerals and produced without cellulose and water. This study focuses on the behavior of screen-printing ink on two different papers, stone paper and coated sticker paper. Properties such as ink adhesion, rubbing resistance, optical printing ink density, ink consumption, and lightfastness were measured on these surfaces. Solvent- and UV-based inks were used, and printing was carried out on cellulose-based (coated sticker paper) and mineral-based (stone paper) paper layers using three different mesh counts (90, 120, and 140 tpc). The rubbing resistance and lightfastness of the papers were also measured. The present findings revealed that stone paper had the same printability properties as cellulose-based paper. The study concluded that using a 140 tpc mesh with both types of ink results in a high-lightfastness ink layer and lower ink consumption. UV-based inks exhibited high rub resistance across all mesh counts. Additionally, when printing with stone paper, there will be a reduction in ink consumption, thereby achieving cost savings. Based on the present findings, it was concluded that water- and oil-resistant stone paper can be considered an essential alternative in many fields, including the printing industry.

Tunable and Non-Invasive Printing of Transmissive Interference Colors with 2D Material Inks.

Interference colors hold significant importance in optics and arts. Current methods for printing interference colors entail complex procedures and large-scale printing systems for the scarcity of inks that exhibit both sensitivity and tunability to external fields. The production of highly transparent inks capable of rendering transmissive colors has presented ongoing challenges. Here, a type of paramagnetic ink based on 2D materials that exhibit polychrome in one magnetic field is invented. By precisely manipulating the doping ratio of magnetic elements within titanate nanosheets, the magneto-optical sensitivity named Cotton-Mouton coefficient is engineerable from 728 to a record high value of 3272 m-1 T-2, with negligible influence on its intrinsic wide optical bandgap. Combined with the sensitive and controllable magneto-responsiveness of the ink, modulate and non-invasively print transmissive interference colors using small permanent magnets are precised. This work paves the way for preparing transmissive interference colors in an energy-saving and damage-free manner, which can expand its use in widespread areas.

Multi-material Direct Ink Writing 3D Food Printing using Multi-channel Nozzle

This paper describes a method for multi-material 3D food printing using a multi-channel nozzle in direct ink writing (DIW) with rapid ink switching. Existing methods for multi-material food printing rely on independently controlled syringes, posing challenges in (1) aligning more than one type of food inks and (2) creating a seamless continuous food filament with different materials. To overcome this limitation, we developed a method using a Y-junction nozzle for seamless ink switching. The use of two inks possessing different rheological properties may result in the backflow of the higher-yield-stress fluid into the channel of the lower-yield-stress fluid, which was addressed by designing the channel sizes to limit the backflow. We successfully demonstrated continuous printing of two food inks exhibiting a yield stress difference on the order of > 102. Real-time switching of the materials can delay deposition at the intended location, which was overcome by introducing an offset distance to the toolpath, resulting in a 74% reduction in print errors. Lastly, we demonstrated the Y-junction nozzle for co-laminar extrusion of two food materials, enabling anisotropic arrangements in 3D food objects. Our approach applies the Y-junction nozzle for multi-material 3D food printing, with broad applicability to various edible inks.

Applicability of normalized resistance rate model for predicting fatigue life and resistance evolution in composite conductive inks

The electrical resistance of metal-polymer conductive inks increases as they undergo cyclic loading, posing a major challenge to their reliability as interconnect materials for flexible electronic devices. To characterize an ink’s fatigue performance, extensive electro-mechanical testing is usually performed. Phenomenological models that can accurately predict the resistance increase with cyclic loading can save time and be useful in flexible conductor design against fatigue failure. One such model was recently developed for only one composite ink type. The model is based on experiments monitoring resistance under monotonic stretch data and multiple experiments measuring the rate of increase of the resistance under different strain amplitudes and mean strains. The current work examines whether such resistance rate model could be generalized to apply for more types of composite inks. Two composite inks with different binder material, metal flake sizes and shapes, and substrate material were experimentally tested under monotonic and cyclic loading. It was found that the two new inks are also more sensitive to strain amplitude than mean strain. The resistance rate model accurately predicts early/catastrophic failure (<1000 cycles) in all inks and conservatively estimates high fatigue life for low strain amplitudes. A protocol detailing the procedures for applying the resistance model to new inks is outlined.

Thermally and magnetically responsive single layer bioinspired soft actuator with patterned structure obtained by direct ink writing

Multi-stimuli hydrogels are an important class of soft actuators, as they allow to expand the range of possible movements and responses by more closely mimicking living matter. Here we report the fabrication of thermally- and magnetically-responsive single layer hydrogel nanocomposite obtained by direct ink writing. Two types of inks, namely, thermosensitive based on poly(N-isopropylacrylamide) (PNIPAM), and magnetically-sensitive based on magnetite particles, were distributed according to a certain pattern, forming a single-layer hydrogel sheet. Thermally-responsive inks due to “coil-to-globule” transformation of PNIPAM at temperatures above 32°C in aqueous solutions generate local internal stresses which lead to the transformation of the hydrogel’s shape. Magnetically sensitive ink allows to move the hydrogel in the space by attracting it to a magnet. Inks' formulations have been optimized to achieve thixotropic properties for the application of direct ink writing. The proposed hydrogel system represents a powerful platform for the development of biomedical soft robots because it consists of biocompatible components and operates in a temperature range close to the human body.

Evaluation of Various Types of Alginate Inks for Light-Mediated Extrusion 3D Printing.

Naturally derived biopolymers modifying or combining with other components are excellent candidates to promote the full potential of additive manufacturing in biomedicine, cosmetics, and the food industry. This work aims to develop new photo-cross-linkable alginate-based inks for extrusion 3D printing. Specifically, this work is focused on the effect of the addition of cross-linkers with different chemical structures (polyethylene glycol diacrylate (PEGDA), N,N'-methylenebisacrylamide (NMBA), and acrylic acid (AA)) in the potential printability and physical properties of methacrylated alginate (AlgMe) hydrogels. Although all inks showed maximum photo-curing conversions and gelation times less than 2 min, only those structures printed with the inks incorporating cross-linking agents with flexible and long chain structure (PEGDA and AA) displayed acceptable size accuracy (~0.4-0.5) and printing index (Pr ~1.00). The addition of these cross-linking agents leads to higher Young's moduli (from 1.6 to 2.0-2.6 KPa) in the hydrogels, and their different chemical structures results in variations in their mechanical and rheological properties. However, similar swelling ability (~15 swelling factor), degradability (~45 days 100% weight loss), and cytocompatibility (~100%) were assessed in all the systems, which is of great importance for the final applicability of these hydrogels.

Exploring volatile organic profiles of red pen inks based on gas-chromatography-flame ionization detection (GC-FID) and chemometric methods for forensic investigation purposes

Criminal cases involving questioned documents often cause the loss of a huge amount of money in a country. Red ballpoint pen inks found on threatening notes, or any official documents are potentially encountered by a forensic document examiner as questioned documents. Identifying sources of the questioned ink entries is paramount to revealing the authenticity or sources of the document. Despite the multitude of works being devoted to discriminating pen inks by their sources, very little is focused on the volatile fractions. In this study, the volatile compositional profiles of ten types of red ballpoint pen inks as acquired by gas chromatography-flame ionization detection (GC-FID) were studied using various multivariate exploratory tools. Scores plot of principal component analysis reveals that inter-pen brand variation is higher than the inter-pen type variation. Meanwhile, hierarchical clustering analysis showed that 6 of the 10 pen types and all five pen brands could be discriminated. In conclusion, volatile organic compositions of red pen inks are useful in classifying the pen inks by brands. The outcome of the study will provide vital insight into the potential of volatile organic profiles in discriminating red pen inks sold in Malaysia.

Biomimetic Scaffolds-A Novel Approach to Three Dimensional Cell Culture Techniques for Potential Implementation in Tissue Engineering.

Biomimetic scaffolds imitate native tissue and can take a multidimensional form. They are biocompatible and can influence cellular metabolism, making them attractive bioengineering platforms. The use of biomimetic scaffolds adds complexity to traditional cell cultivation methods. The most commonly used technique involves cultivating cells on a flat surface in a two-dimensional format due to its simplicity. A three-dimensional (3D) format can provide a microenvironment for surrounding cells. There are two main techniques for obtaining 3D structures based on the presence of scaffolding. Scaffold-free techniques consist of spheroid technologies. Meanwhile, scaffold techniques contain organoids and all constructs that use various types of scaffolds, ranging from decellularized extracellular matrix (dECM) through hydrogels that are one of the most extensively studied forms of potential scaffolds for 3D culture up to 4D bioprinted biomaterials. 3D bioprinting is one of the most important techniques used to create biomimetic scaffolds. The versatility of this technique allows the use of many different types of inks, mainly hydrogels, as well as cells and inorganic substances. Increasing amounts of data provide evidence of vast potential of biomimetic scaffolds usage in tissue engineering and personalized medicine, with the main area of potential application being the regeneration of skin and musculoskeletal systems. Recent papers also indicate increasing amounts of in vivo tests of products based on biomimetic scaffolds, which further strengthen the importance of this branch of tissue engineering and emphasize the need for extensive research to provide safe for humansbiomimetic tissues and organs. In this review article, we provide a review of the recent advancements in the field of biomimetic scaffolds preceded by an overview of cell culture technologies that led to the development of biomimetic scaffold techniques as the most complex type of cell culture.

Comparison of the Quality of Ink Prints on the Market on Coated and Uncoated Paper

Printing inks of various brands are available in the field. Available colors include Cyan, Magenta, Yellow, and Black. Ink is an important parameter in determining print quality. Optical density is one of the important parameters used to control print quality. The optical density of the printed material is a form of ink–paper interaction. This research is oriented toward investigating the optical density value of Cyan printing ink on coated and non-coated paper. The main objective of this research is to analyze the effect of printing ink thickness on the optimal density value. Optical density values of Cyan prints were obtained using densitometer measurements, printed with the IGT method on coated and uncoated paper. The optical density values of several types of ink on the market that have been printed on coated and uncoated paper have never been reported before.&#x0D; Keywords: printing ink, coated paper, uncoated paper

Piezoelectric-pneumatic material jetting printing for non-contact conformal fabrication of high-temperature thick-film sensors

Conformal printing of high-temperature thick-film sensors (TFSs) on intricate surfaces is crucial for precise integration and enhanced functionality. However, traditional contact printing faces challenges in terms of the complex motion control of 3D surfaces. With the core concept of non-contact printing, this study employs piezoelectric-pneumatic material jetting (PPMJ) to achieve rapid and uniform manufacturing of complex and multi-material conformal TFSs. PPMJ enables a wide viscosity range (50–100,000 mPa.s) and high solid content (60 wt%), accommodating various types of inks, from insulating to semiconductor materials to high-temperature alloy slurries, thus providing a broad operational window for shape control and performance modulation in the conformal manufacturing of TFSs on curved surfaces. Microscale shape control of ceramic ink features, including a parallel three-phase contact line, uniform print dimensions, and post-curing shape control, was systematically investigated. PPMJ printing facilitates the successful in situ fabrication of multi-layer TFSs, featuring the self-assembly of droplets and dependable printing consistency, with nozzle-to-substrate heights ranging from 1 to 10 mm, thus advancing the structural arrangement, design, and manufacturing of conformal multi-layer TFSs on curved surfaces. For example, the polymer-derived ceramic heat flux sensor printed by PPMJ demonstrates repeatable high-temperature responsiveness and can be integrated on the surface of turbine blades, withstanding thermal impacts from flames exceeding 800 °C. Hence, PPMJ printing technology opens new possibilities for the conformal manufacturing of various sensors on complex 3D surfaces.

Physical Characteristics of Sintered Silver Nanoparticle Inks with Different Sizes during Furnace Sintering.

The influence of nanoparticle (NP) size on the physical characteristics of sintered silver NP ink was studied using four different types of inks. The Ag NP inks were spin-coated on glass substrates with an average thickness of 300 nm. Each sample was sintered for 30 min, with temperatures from 50 °C to 400 °C by an interval of 50 °C. After sintering, the specific resistance of each case was obtained using the resistance and surface profile measurements. The minimum specific resistance obtained by the experiment was 2.6 μΩ·cm in the case in which 50 nm-sized Ag NP ink was sintered at 350 °C. The transformed surface morphology and grain size of each case were observed using scanning electron microscopy and atomic force microscopy. The results of this study can be a reference for future manufacturers in selecting the Ag NP size and the sintering temperature.

Systematic study of a method to determine the sequence of crossing lines on stamping before writing.

Determining specific line-crossing sequences has always posed a challenge for document examiners. Interactions between pen ink and stamp seal ink can be complicated and changeable due to the many seals and writing inks available in the market. This study determines the line-crossing sequence of stamping before writing by observing the influence of seal ink on pen writing. The results of examining four types of pens and six types of seal ink crossings reveal that assessing the completeness of writing strokes can determine sequencing. Different ink types interact to produce different phenomena. In addition, time interval and pen structure affected the interaction between two inks in a crossing. A 70% accuracy rate was achieved in a nationwide blind test, which will be discussed in this article.

Environmentally Sustainable Offset Prints Exposed to Thermal Aging and NO2

The research aims to find out the crucial factors in the design phase of packaging products, which are related to the determination of environmental influences on sustainable materials. The paper presents the results of research into the influence of environmentally friendly cardboard and the separation of yellow offset ink on the optical properties of prints exposed to thermal aging without and with exposure to NO2. The samples were obtained under real conditions on a Roland 705 printing machine. The colorimetric characteristics of the print and its stability were determined in the research. The research is significant for graphic reproduction in the domain of testing the quality of the print itself, which is defined by certain raster characteristics. The research covers prints in 100%, 70% RTV, 50% RTV, and 30% RTV. The intensity of the tonal experience will depend on the interaction of the substrate with the raster and different types of inks in offset printing as a function of the experimental conditions. The ink characteristics of prints ∆L*, ∆a*, ∆b*, and ∆E were determined. The research results show that ink I1, with about 80% renewable raw materials, achieves the best stability under the specified experimental conditions.

A hyperspectral unmixing approach for ink mismatch detection in unbalanced clusters

Detecting ink mismatch is a significant challenge in verifying the authenticity of documents, especially when dealing with uneven ink distribution. Conventional imaging methods frequently fail to distinguish visually similar inks. Our study presents a novel hyperspectral unmixing approach to detect ink mismatches in unbalanced clusters. The proposed method identifies unique spectral characteristics of different inks employing k-means clustering and Gaussian mixture models (GMMs) to perform color segmentation on different ink types and utilizes elbow estimation and silhouette coefficient to evaluate the number of inks estimation precisely. For a more accurate estimation of quantity, which is generally not an attribute of clustering methods, we employed entropy calculations in the red, green, and blue depth channels for precise abundance estimation of ink. This unique combination of basic techniques in conjunction exhibits better efficacy in performing ink unmixing and provides a real-world document forensic solution compared to current methods that rely on assumptions like prior knowledge of the inks used in a document and deep learning-based methods that rely heavily on abundant training datasets. We evaluate our approach on the iVision handwritten hyperspectral images dataset (iVision HHID), which is a comprehensive and rich dataset that surpasses the commonly-used UWA writing inks hyperspectral images (WIHSI) database in size and diversity. This study has accomplished the unmixing task with three main challenges: unmixing of diverse ink spectral signatures (149 spectral bands instead of 33 bands in the previous dataset), without using prior knowledge and assumptions about the number of inks used in the questioned document, and not requiring large training data for performing unmixing. Furthermore, the security of the proposed document authentication methodology to address the likelihood of forgeries or manipulations in questioned documents is enhanced as compared to previous works relying on known inks and known spectrum. Randomization techniques and anomaly detection mechanisms are used in our methodology which increases the difficulty for adversaries to predict and manipulate specific aspects of the input data in questioned documents, thereby enhancing the robustness of our method. The code for conducting this research can be accessed at GitHub repository.