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Colour distributions of patches for the IT8.7/2-1993 chart (circles) and in ColorChecker DC chart (stars) as measured when printed onto cotton
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A low-cost four-colour (RBYK) dye-based ink-jet printing system for textiles was introduced in this study, in which red and blue inks were employed instead of the magenta and cyan inks used in half-tone printing. The basis of a colour-management system for this device was developed by determining the mapping between XYZ tristimulus values of output...
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Printed textile materials are often exposed to certain external impacts. One of the most common impact, these materials are subjected to, is thermal load. This effect causes certain changes in textile fibers as well as changes of ink colour reproduction printed on these materials. In this paper is presented an investigation of the series of thermal...
Leuco dye-based thermochromic printing inks are one of the candidates for active packaging of the future. Such an advanced application requires much more knowledge about these novel inks as it is currently provided by the manufacturers. Thermochromic inks reversibly change from colored to discolored state in a certain temperature region. Details of...
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... The quality and reproducibility of the printed fabric products are inseparable from the ink performance. The ink performance not only determines the ink ejection, but also significantly impacts the reproducibility and sharpness of the printed fabric [13][14][15][16][17][18]. Thus, the digital inkjet technology can be envisaged to be applied to textile printing to a much greater extent if the high matching printing inks are successfully developed. ...
... The ejection performance is the combined result of the nozzle parameters (nozzle orifice diameter, nozzle interface material, etc.), driving waveform parameters (driving voltage, waveform and pulse time) and physicochemical properties of ink (viscosity, surface tension and density) [13][14][15][16][17][18]35,36,38,46]. Under the conditions of determined nozzle parameters, the ejection performance of ink mainly depends on the driving waveform parameters and the physicochemical properties of ink [46]. ...
... Many factors affect the quality of the inkjet printing patterns, such as inkjet printing machine, fabric structure, fabric pretreatment, ink components, ink drop parameters and fixation process conditions [13,15,35]. Based on the fixation process conditions for the inkjet printing of fabric using the disperse ink 3c (Table 6), it can be seen that the K/S value of the printed fabric (3.36-12.49) ...
In textile inkjet printing, it is important to understand the design theory of ink jet printing ink. In this study, according to the solubility parameters of printing ink components (humectant, penetrant, pH regulator, viscosity regulator and deionized water), twelve different complex solvents were designed to prepare disperse ink. By observing the particle size, stratification, rheological property and viscosity of the prepared inks, the ink meeting the requirements was subsequently selected. The low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) analyses were used to analyze the water distribution and structure information of the ink at the micro level, which provide opportunities to subsequently interpret the macro properties (fluidity) of ink. The ink before and after filtration was tested using an ultraviolet-visible spectrophotometer (UV), and the content of the disperse dye in the ink was observed to be reduced after filtration. The viscosity of the ink before and after filtration were also analyzed. The viscosity of the ink was noted to significantly decrease after filtration, which indicated that the content of the disperse dye in the ink exhibited a vital influence on the ink viscosity. LF-NMR was applied to study the stability of ink (1a, 1c, 3a, 3c, 4a, 4c, 5a, 5c, 6a and 6c) in cold and hot environments. No new peak was found in T 2 relaxation time inversion spectra of disperse ink, which indicates that there is no physical or chemical change among the components in disperse ink. The voltage of the driving waveform was adjusted and ejection performance of different inks was characterized. The results indicated linear driving voltage and ligament length of the inks. Different fixation temperatures (160 ℃-190 ℃) were used to optimize the fixation temperature of the printed fabrics, and 180 ℃ was determined to be the optimal fixation condition. Finally, the color fastness of the printed fabric was tested and analyzed. The findings revealed that the color fastness of the printed fabric met the use requirements.
... CMYK, Cyan, Magenta, Yellow and Key/Black) that absorb lights of certain wavelength from the ambient light, and reflect the others to the observers' eyes. Subtractive colour models usually lead to a non-linear or non-polynomial relationship between the input RGB and output CIE standards 11,16 . The 3D printer employed here uses a similar CMYK colour model but with an additional white base material. ...
This study aimed to develop a three-dimensional (3D) colour reproduction system to improve the aesthetic effects of dental prostheses. The system’s colour accuracy was also evaluated. Based on the concept of colour management, 96 colour patches were selected to develop colour profiles for an intraoral scanner and a 3D printer using polynomial regression. The colour differences ΔEab⁎ between colour patches reproduced using different colour profiles and the original colour patches were analysed to select the best combinations of colour profiles. The 3D colour reproduction system with the best-performing (i.e. third-order polynomial regression) colour profiles was finally evaluated using tooth and gum shades. The median ΔEab⁎ was 6.940 ranging from 1.504 to 32.660. In terms of tooth and gum shade, the median ΔEab⁎ was 6.313, and half of the shade blocks were above the mismatch threshold (ΔEab⁎ > 6.80). In conclusion, the colour management based on polynomial regression can decrease the colour difference of the 3D colour reproduction system, but not to clinically acceptable levels. Further advances are needed to improve the methods and hardware.
... Zhang et al. used direct dyes in ink recipe for printing of cotton fabrics. 3 Instead of using cyan and magenta tones of direct dye, they were replaced with blue and red tones, respectively. The ink-jet printing of pretreated cotton with 2,3-epoxypropyltrimethylammonium chloride was also investigated by Kanik et al. 4 The treated and untreated cotton fabrics were then printed by a series of reactive dyes with different tones including cyan, magenta, yellow and black. ...
A special printing ink formulation based on cationic dyes is developed for digital printing of acrylic fabrics using a conventional inkjet printer. In order to investigate the contribution of color gamut boundary of printer colorants to printing efficiency, customized color targets containing 3164 color patches in 25 different hues were generated. The printed color patches were then fixed through steaming for 30 minutes followed by washing with hot soap and water and finally drying. To show the influence of dye fixation on colorimetric changes as well as color gamut boundary of samples, the L*a*b* values of color patches before and after fixation process were compared. Results demonstrate that color saturation of samples is enhanced dramatically after the dye fixation process. In fact, 3D color gamut of color patches has been drastically expanded as a direct consequence of adsorption to absorption transition. Additionally, dye fixation changes the structure of printed image from halftone superimposed dots to contone superimposed dyes. Strictly speaking, during fixation process, colors inside the halftone dots diffuse through the interfacial area to make the individual printed dots integrated. This is in analogy to the chromogenic photography films and dye-sublimation thermal transfer processes by which contone images are produced. Moreover, dye fixation improves the washing fastness of digitally printed acrylic fabrics to the level comparable with the traditional screen printing method.
... [2] This paper mainly focuses on the former process. Many mathematical models have been employed during color characterization, such as the spectral Neugebauer equations, [3,4] Kubelka-Munk model, [5] polynomial functions based on least-squares, [6,7] artificial neural networks (ANNs), [8,9] 3D interpolation techniques, [10][11][12][13] and so on. Spectral Neugebauer equations are established based on subtractive coloring principle and widely used for color characterization. ...
... In Eq. [7] the predicted reflectance R k ð Þ of Eq. [4] is replaced by the measured reflectance R m (k min ) so as to obtain the best matching effective area coverage. Moreover, because the wavelength k is actually a matrix of wavelength, an appropriate ...
... In Fig. 2, the reflectance of cyan, magenta, and yellow inks within the range of 400-700 nm are described, and the circle represents the wavelength k min for individual inks. Because the reflectance data is a continuous function of wavelength within the visible spectrum, it is more accurate when Eq. [7] is written into a spectral form, and the expected a eff should make the predicted reflectance match the measured reflectance data as far as possible. Thus when the reflectance data are measured at intervals (e.g., 10 nm) and expressed as vectors, the discrete form of Murray-Davies model can be written as below: ...
Spectral Neugebauer model is widely used for spectral reflectance prediction during printer characterization. However, several factors reduce the predication precision. Thus, an improved cellular Yule-Nielson spectral Neugebauer (CYNSN) model is proposed, which modifies the traditional spectral Neugebauer model in three main aspects: (1) First, in order to adjust the nonlinearities between the predicated and measured spectral reflectance, an iteratively calculated Yule-Nielson exponent is added to the reflectance values within the Neugebauer equations. (2) Second, the quantity of Neugebauer primaries is increased by dividing the CMY colorant space into 43 uniform cellular subdomains. (3) Third, the mapping functions are developed to map the area coverages' theoretical values to their effective values within the subdomains, and the mapped values highly improve the matching degree of the predicated and measured reflectance values. In the experiment, four related spectral Neugebauer models are employed during printer characterization, which are the traditional spectral Neugebauer model, Yule-Nielson spectral Neugebauer (YNSN) model, traditional CYNSN model, and the modified CYNSN model, respectively. And the experimental results show the modified CYNSN model yields a significant improvement over the other spectral Neugebauer models, by comparing the characterization errors in the form of colorimetry and spectroscopy.
In the present study, density functional theory (DFT) has been used in simulating and calculating the molecular geometries of differently structured polyols (within a water phase), as well as the weak interactions between these polyols and the water molecules. Furthermore, low field nuclear magnetic resonance (LF-NMR) has been used in studying the transverse relaxation times of different polyols, in addition to their (20.00 wt %) fluidity in an aqueous environment. Moreover, the influence of polyols, with different molecular structures, on the ink fluidity, was also explored. A bubble pressure tensiometer was also used to characterize the surface tension of the aqueous polyol (20.00 wt %) solution, the sodium dodecyl sulfate (SDS, 0.50 wt %) solution, and the ink. This was made to clarify the influence of polyol and SDS on the surface tension of ink. In addition, the particle size, zeta potential, pH value, viscosity, and rheological properties of the ink, were also investigated. The resulting data showed that polyols have certain effects on the particle size, stability, and viscosity of the ink. The jetting performances of different polyol inks were, under certain conditions of the inkjet drive waveform, also explored. The results showed that the fluidity, viscosity, and surface tension of the ink will render a certain influence on the inkjet performances. The prepared polyol ink was thereafter used for polyester fabric printing, and the contour sharpness and color fastness of the printed fabric were accordingly evaluated. The data showed that the increase in ink viscosity, and decrease in fluidity, promote the improvement in contour sharpness. In addition, the printed fabric demonstrated an excellent color fastness.
We report an improved printing ink of polyester fabric employed in the production process of inkjet printing. In the design of printing ink, the solubility parameters of reagent and HLB value of surfactant are used to prepare the ink. This production process does not require the pretreatment of polyester fabric to directly carry out inkjet printing. By regulating the intermolecular force relationship between the components of ink and the compactness of ink microstructure, it can improve the diffusion of ink on the surface of polyester fabric. The low-field NMR (LF-NMR) revealed the correlation between the fluidity and transverse relaxation time of main reagent solutions and ink. The test results show that there are three types of water: hydrogen-bond water, bound water and free water in main reagent solutions and ink. The LF-NMR was also used to investigate the relationship between ink viscosity and transverse relaxation time. It was observed that the transverse relaxation time (1084.4–410.3 m s, peak maximum time of T22) of ink decreases with the increase of ink viscosity (2.3–11.1 mPa s). The viscosity and transverse relaxation time of ink is associated with the intermolecular force and the compactness of microstructure of ink. The formation of ink droplets was systematically observed by the ink droplet observation instrument. When the surface tension and viscosity of ink are 32.2–37.4 mN/m and 2.3–8.8 mPa s, respectively, the ink can be smoothly inkjet. With the increase of viscosity of the ink (2.3–8.8 mPa s), the sharpness of printing pattern is obviously improved, and the change rate of the line width (W) of the printing pattern is reduced from 52.6% to 4.4%. The microstructure of ink can bound the solvent of the ink, reduce the fluidity of the solvent, and improve the sharpness of the printing pattern. The test results of KES style and color fastness of the printed fabric show that the printed fabric fully meets the wearing requirements. Compared with other the soap liquid of printed fabric, the soap liquid of printed fabric RD-2B has strong UV absorption strength, the soap liquid RD-2B has a higher dye content. The characterization results of volatile organic compounds (VOC) in ink SDS R7 is 17.0 g/kg. The chemical oxygen demand (COD) values of printed fabrics RD-2B and SDS R7 are 150.0 and 102.0 mg/L, and the biochemical oxygen demand (BOD5) values of printed fabrics RD-2B and SDS R7 are 130.0 and 97.7 mg/L. Compared with the common polyester fabric printing ink (ink RD-2B), the prepared ink has the characteristics of environmental protection, high production efficiency and low energy consumption, which has the potential to achieve green printing.
In this paper, we use density functional theory (DFT) to optimize and calculate the geometries and vibration frequencies of H2O, EG (ethylene glycol) or H2O/EG in the ink (B3LYP/6-311++G** basis set, self-consistent reaction field theory (SCRF) and PCM polarization unified field model). LF-NMR (low-filed nuclear magnetic resonance) further confirmed the weak interaction between H2O, EG or H2O/EG molecules, which had a decisive influence on the viscosity and mobility of ink. According to the analysis of the peak of the inversion spectrum (T22) of the ink, the viscosity of the ink increases with the left shift of the relaxation time. The inkjet performance of the ink is closely related to the physicochemical properties of the ink and the driving waveform of the piezoelectric nozzle. Exploration of the sharpness of the inkjet printing pattern that the microstructure and weak intermolecular interaction of the ink bounds the mobility of the solvent in the ink, which increases the viscosity of the ink (3.28-5.11 mPa.s), and the ink overcomes the capillary effect of the fabric, which makes the diffusion of the ink in the fabric decrease (7.23-3.91 %).
The study aims to investigate the effect of additives (poly (vinyl pyrrolidone) PVP, glycerol, ethylene glycol) on the performances of disperse water-based inks for ink-jet printing and how such additives interact with water. This should help into design suitable inks for textile printing by ink-jet printing, in particular for synthetic fibers such as polyester fabrics. Thirteen kinds of inks were prepared, and the glycerol content was replaced by water and PVP (K15, K30, K60), and the solubility parameter of the additive was calculated by the group contribution method. Low field nuclear magnetic resonance (LF-NMR) reveals the existence of bound water, intra-microstructure water, and extra-microstructure water in the ink, and the intra-microstructure water is entrapped inside the micro-structure formed by additives, mainly due to the presence of PVP. The optimal ink (Y5K30) has a low linewidth relative change (0.4%) and excellent sharpness. The reason is the existence of microstructure in ink, which reduces the mobility of solvent in ink and the diffusion of ink on fabric. PVP and disperse dyes have a strong affinity and help to improve the color depth and color fastness of the fabric.
The preparation of disperse inks for direct inkjet printing was carried out using disperse dye, dispersant (TD-1109, hydrophilic polyacrylic acid block copolymer), wetting agent (diethylene glycol and ethylene glycol), water-based polymers (polyvinyl alcohol (PVA) or waterborne polyester), deionized water, etc. The suitability of disperse inks for polyester fabrics was assessed via measurement of conductivity, pH, particle size surface tension and viscosity. The theological behavior of disperse inks was evaluated by rotational viscometry; the disperse inks had the characteristics of a Newtonian fluid. The inkjet printability of disperse inks was investigated by monitoring droplet formation dynamics, where the viscosity and surface tension of disperse ink were 2.78 mPa s and 33.28 mN m-1, respectively. The disperse ink has excellent ejection performance. The printing accuracy of disperse inks was evaluated by inkjet printing quality of lines on untreated polyester fabrics. The fastness properties of printed polyester fabrics were also evaluated and they presented excellent color fastness. Compared with different printed polyester fabrics, the polyester fabrics printed with disperse ink made from water-based polymers have high color strength (K/S) and saturation (C*) values.
Two water based disperse inkjet inks for polyester textile printing with antibacterial properties were prepared. The antibacterial activity was due to the presence of polyhexamethylene bisguanidine (PHMBG). The surface tension, pH, viscosity and conductivity of all inks formulations were monitored over a period of time for the evaluation of ink stability and suitability. The inks were used for application on polyester and polyamide samples by exhaustion (dyeing) and wash, light fastness and colour measurements were made on the dyed samples. The optimum application level required to give long lasting antimicrobial protection was determined by carrying out a series of antimicrobial testing.
