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Original scientific paper This paper presents experimental usage of updated control methods such as thermovision and spectrophotometric analysis in graphic industry. These methods were applied to research the influence of ink volume and material characteristics on colour and heat treated printed substrates. Samples used in these experiments were printed by digital ink jet printing technique using Mimaki JV22 printing machine and J-Eco Subly Nano inks. As printing substrates, three different types of materials were used. Materials were different in respect of fabric weight and thread count, while material composition was the same for all three materials. The appropriate test card consisting of fields of CMYK colours was printed, varying the number of ink layers applied. Samples were exposed to heat treatment after printing. The heat applied was measured by thermovision camera. Spectrophotometric measurements were conducted before and after heat treatment. Based on data gathered by spectrophotometric measurements colour difference ΔE76 was calculated. Results showed that increasing number of layers, as well as right choice of substrates, can improve behaviour of printed product during exploitation. Keywords: digital textile printing; heat treatment; ink layers; material characteristics Termovizijska i spektrofotometrijska analiza diferenciranog nanosa boja na specifične podloge izložene toplinskim opterećenjimaIzvorni znanstveni članak U radu su predstavljene primjene suvremenih metoda kontrole, kao što su termovizijska i spektrofotometrijska analiza, u grafičkoj industriji. Suvremene metode kontrole primijenjene su pri istraživanju parametara diferenciranog nanosa boje na specifične podloge izložene toplotnim opterećenjima. Uzorci koji su rabljeni za istraživanje odštampani su Ink jet postupkom na digitalnom tiskarskom stroju Mimaki JV 22 koja koristi J-Eco Subly nano boje. U procesu tiska, rabljene su tri vrste podloga, pri čemu je za sve njih sastav materijala bio isti, ali su se razlikovale prema parametrima površinske mase i gustoće pletenja. Odgovarajuća test karta koja se sastojala od polja CMYK otiskana je s pet različitih nanosa boje. Ti uzorci su izloženi toplinskom djelovanju, pri čemu je polje toplinskog djelovanja mjereno termovizijskom kamerom. Uzorci su analizirani spektrofotometrijskim mjerenjima prije i poslije toplinskog djelovanja te je na osnovu tih podataka određena vrijednost razlike boje (ΔE76). Dobiveni rezultati su pokazali da povećanje broja nanosa boje, kao i odabir odgovarajuće podloge za štampu, može povećati eksploatacijske karakteristike otisaka.

The surface of textile materials is highly textured, commonly in non-uniform ways. Because of this texture effect, textile surface appears rougher and more porous than other printing substrates, which can cause excessive ink penetration during printing process. Next, washing process is very important factor because it influences ink characteristics on printed samples as well as structural changes of the textile substrate. The aim of this paper is to determine the influences of washing process and different mesh tread count used for printing on print quality. This will be obtained by using spectrophotometric analysis, and GLCM image processing method for print mottle estimation. The results of this research show that increasing number of washing processes leads to higher color differences reproduction color in comparison to printed materials before washing. It also shows that textile surface texture has a great influence on print mottle as well as that number of washing treatment series can generate variations of solid-tone print uniformity.

During exploitation, textile products printed with screen printing technique are quite often exposed to various influences, one of which is a heat treatment-firstly during the production process and later on when ironing. Heat is simultaneously affecting deposited colorants (ink) on the surface of the substrate material, as well as textile fibers in the material structure. As a result, colorimetric characteristics of printed colorants are changed. The research presented in this paper aims to determine the influence of heat treatment on color changes of screen printed textile substrates, observed in CIE L*, a*, b* color space. Macro non-uniformity of the printed cotton textile materials was analyzed as a function of temperature levels applied during thermal treatments and textile material characteristics, as well as mesh counts of screens used in the printing process. The results show that thermal treatment affects the color change of printed samples.

Microcapsules are used in various fields of application, such as in pharmacy, medicine, agriculture, chemical industry, construction industry, food industry, biotechnology, electronics. Fragranced and PCM (phase change materials) microcapsules also found their use in the printing and the textile industries, where they are applied in the combination with the appropriate ink or varnish on the desired substrate material. Microcapsules are applied either by coating or by different printing techniques, which main advantage is the ability to transfer the microcapsules onto desired areas of the substrate material without or with as little damage as possible, thus allowing the deposited microcapsules to fulfil their basic functionality. The aim of this research was to investigate the morphologic characteristics of the fragranced microcapsules and the coated prints using selected varnish and different fragranced microcapsules concentrations, as well as to determine how variable concentrations of the applied microcapsules in the varnish affect the optical characteristics of the coated prints. Performed SEM (scanning electron microscopy) and spectrodensitometric analyses of the coated prints revealed that both the coating process without microcapsules, as well as the different fragranced microcapsules' concentration in the coated water-based varnish, significantly affected both the morphologic and the optical characteristics of the coated prints.

The human body has developed a thermo-regulatory system that maintains an inner body temperature of approximately 37°C. At excessive body temperatures, sweat mechanisms activate, resulting in a decrease in body temperature through sweat evaporation. Garments, depending on their characteristics, extensively affect the heat interchange process between the human body and the environment. Different printing processes change the characteristics of textile materials and therefore the garments made from these materials. This paper investigates the influence of digital printing parameters on the thermo-physiological features of textile materials. The effects of printing parameters on thermo-physiological characteristics of substrate materials were determined by measuring water vapour resistance. The obtained results show that printing parameters, in combination with material composition and material texture, have a large effect on the thermo-physiological characteristics of textiles.

Clothes are exposed to diff erent impacts during usages and maintenance. The more frequent impacts on textile materials are the washing processes and the perspiration eff ects. These mentioned eff ects are the causes of specifi c changes of the textile fi bres and on colour reproduction on printed materials. This paper presents research into the impacts of a series of washing and perspiration eff ects on the colour reproduction studied with a spectrophotometric analysis and the water retention capacities of the prints using the screen-printing technique. The research results indicate that with the increase in the number of washes, major changes occurred in the reproduced colours compared to the colours of the samples that did not undergo the process of washing. It was determined that, besides the series of washings, the perspiration effects also had an impact on the reproduced colour changes. The impacts were also affi rmed of printing and a series of washings on water retention on textile materials.

The human body transforms the chemical energy of the food into the work and the heat through the process of metabolism. The produced heat through the skin is transferred to the environment. In this case, in the state of thermal equilibrium, the amount of heat produced is equal to the amount of heat lost by conduction, convection, radiation, evaporation and breathing. The process of conduction of heat is transferred from the body to the environment, through layers of clothing and air, with the person standing still. Conductivity of heat in clothes depends on the thermal conductivity of the fibers from which the clothes are made, the conductivity of the air trapped in the pores of the clothes and the air on the surface of the clothing, the surface of the clothing layer through which the heat and the thickness of the clothes pass. The amount of heat transferred by conduction is usually negligible because the clothing, by its characteristics, slows down heat transfer in this way. Additionally, ink layers made in printing process significantly affect the properties of textile materials and clothes made from these materials. And today textile materials are increasingly being subjected to the process of printing due to aesthetic requirements of the people. This paper investigates the influence of digital printing parameters on the thermo-physiological features of textile materials. The essential print parameter was a different number of passes. In this research were used textile fabric materials of 100% cotton fibers. With printing process parameters, such as number of passes in the print, it is possible to influence the amount of ink that is applied on and in printed material, and thus the achievement of desired values of thermal parameters of printed materials. The influence of print parameters to thermo-physiological properties of the material is evaluated through a thermal conductivity and heat retention ability. Results of the research demonstrated that, in addition to material composition, the printing process with its parameters have a significant influence on the thermo-physiological characteristics of textile materials. The values of the thermal conductivity of the printed samples show that the increase in the number of application of ink in the printing results in a rise in the value of thermal conductivity coefficient, and decrease in heat retention ability value.