In accordance with environmental sustainability and in order to optimize the recycling process of... more In accordance with environmental sustainability and in order to optimize the recycling process of prints from indirect electrophotography with liquid toner the results of investigating the effects of changes in printing conditions on the characteristics of recycled fibres is presented. Changing of printing machine conditions, respecting of voltage variations, comprises of the reverse rollers and intermediate cylinder. Based on the results it can be concluded that the change in the voltage of the reverse rollers more affect the recycling efficiency with respect to the voltage change of the intermediate cylinder. Brightness gain is higher when the print for recycling is made on uncoated paper compared to coated, and dependent on the voltage changes. Effective residual ink concentration decreases far more on handsheets obtained from recycled samples on uncoated paper in relation to both sides coated paper. Increasing the positive voltage of intermediate cylinder and increasing the negative charge of reverse rollers increases the 3 D gamut CIE L*a*b* color cubic units. Guidelines for the size of the voltage in order to obtain optimal print reproduction are provided. The further research will include the development in area of clean technologies, advanced materials, closed loop systems; therefore the significant terms in the area of environmental sustainability.
The results from an investigation of the colour characteristic and changes in the size and shape ... more The results from an investigation of the colour characteristic and changes in the size and shape of yellow screen elements of LEP (Liquid Electrophotography Printing) prints exposed to moist-heat ageing are presented. Three sample series are analysed: prints on the non-aged paper, accelerated aged prints and prints on accelerated aged paper. The results showed that prints on the aged recycled paper and on aged fine art paper show greater colour change than aged prints on non-aged paper. The tonal values were influenced by such printing substrates on the yellow reproduction. A decrease in colour differences of prints appears on the aged offset paper used as printing substrate by increasing the screen value in area of 10%-20%. Moist-heat aged prints on offset paper influences the decrease of yellow screen elements, which is not the case for the prints made on recycled paper and those made on fine art paper. Printing on the aged paper results especially in a 30% increased reproduction of the screen elements in darker tones. On all the three paper kinds greater deviations were found along the horizontal length of the screen element in comparison to the vertical diameter length. ADDRESSES OF THE AUTHORS: Igor Majnarić ([email protected]), Ivana Bolanča Mirković ([email protected]), Zdenka Bolanča* ([email protected]), University of Zagreb, Faculty of Graphic Arts, Getaldićeva 2, 10000 Zagreb, Croatia, *Croatian Academy of Engineering, Kačićeva 28, 10000 Zagreb, Croatia Corresponding author: Ivana Bolanča Mirković
The directions of the ecological sustainability in printing reproduction are in the area of the a... more The directions of the ecological sustainability in printing reproduction are in the area of the application of the renewable and recycled raw materials, in the decrease of the energy consumption, the usage of the energy from the renewable sources and in the production without waste. This article presents the research results of voltage changes of the intermediate cylinder in indirect electrophotography with liquid toner on dirt count and area on handsheet made from fibers after prints pulping and flotation, brightness and effective residual ink concentration. Since on the indirect transfer of ElectroInk except the voltage of the intermediate cylinder also impacts temperature, its influence on the dirt count and area is showed. Uncoated and both side coated substrates were used for printing. The results show that changes in voltage of the intermediate cylinder in the printing affects the characteristics of pulped and floated fibers and dirt count and area on handsheets. Dominant factor of studied process is surface treatment of the printing substrate. Maximum efficiency of deinking flotation (87.7%) was observed on non coated paper print, at the voltage of the intermediate cylinder of 700V. The efficiency of deinking flotation on both sides coated paper prints in dependence on the voltage of the intermediate cylinder in most cases is below 10%. The results show that an increase in temperature of the intermediate cylinder increases dirt count and area on handsheetst after pulping prints under experimental conditions. Increased efficiency of flotation was found for print obtained at a lower temperature of the intermediate cylinder.
In the paper was presented the reconstruction of the printing system which was used in Senj glago... more In the paper was presented the reconstruction of the printing system which was used in Senj glagolitic press established in 1494. In the project special attention was paid to the authenticity of this historical artefact. Here is described a diagram of the flow of the process which begins with research of historical sources and collection of data, then follows the creation of technical documentation, building, testing and evaluation of a replica of the historical press. The work is completed with sketches and drawings, descriptions and explanations of the process of its creation.
The paper the results of efficiency investigation of chemical deinking of non-impact prints, wher... more The paper the results of efficiency investigation of chemical deinking of non-impact prints, where the principle of electrophotography is used for obtaining the latent image, on which the toner could adhere. The basis of scientific prepositions of deinking flotation and the mechanism for particle separation in the explanation of the results of experiment are given. The optical properties of hanh- sheets in relation to the particle separation mechanism, their size, from and structure are discussed. The results obtained by deinking flotation of a mixed sample from the prints of non-impact printing and the conventional offset printing show clearly the influence of the specific characteristic of prints techniques and the chemical composition of toner, i.e. of printing inks on the quality of recycled fibres.
Printing material and prints undergo changes during ageing which can be recognized in deteriorati... more Printing material and prints undergo changes during ageing which can be recognized in deterioration in the physical, chemical and optical properties. The aim of this work is to determine the optical changes of the prints caused by ageing of the printing material and of the prints obtained by the application of the indirect electrophotography. The change of the screen elements in lighter halftone areas, which was obtained by the usage of the microscopic image analysis, has been discussed in the article. For the preparation of samples the following papers were used: fine art paper, recycled paper and offset paper as well as black Electroink. Three sample series were observed: prints on nonaged paper and ElectroInk, prints on aged paper and ElectroInk and prints on aged paper and nonaged ElectroInk. The investigation results show that by ageing of the uncoated printing substrates the decrease of the dots on prints can be expected, while the printing on the aged paper results in the increased reproduction of the halftone dots. The obtained results are the contribution to the explanation of the influence of the accelerated ageing process of papers which are used for printing and the aged prints on the halftone dot changes. Except the mentioned determined scientific contribution the results are applicable in the area of the printing product quality as well as in the forensic science.
The aim of this paper is the result presentation of some optical properties research for ink jet ... more The aim of this paper is the result presentation of some optical properties research for ink jet prints after: exposing the prints to the mixed daylight and artificial light, exposing of prints to the sun-light through the glass window, and exposing of prints to outdoor conditions during the summer months. The prints obtained by piezoelectric and thermal ink jet technologies were used in the researches. The dye-based inks and the pigmented inks based on water and the low solvent inks were used. The results of these researches, except the scientific contribution in the domain of understanding and explaining the environmental conditions on the gamut size, i.e. the range of color tonality, colorimetric stability and print quality, can be used by the ink and paper manufacturers in new formulations, offer data for the printer producers for further production and evaluation of the position of their products.
In accordance with environmental sustainability and in order to optimize the recycling process of... more In accordance with environmental sustainability and in order to optimize the recycling process of prints from indirect electrophotography with liquid toner the results of investigating the effects of changes in printing conditions on the characteristics of recycled fibres is presented. Changing of printing machine conditions, respecting of voltage variations, comprises of the reverse rollers and intermediate cylinder. Based on the results it can be concluded that the change in the voltage of the reverse rollers more affect the recycling efficiency with respect to the voltage change of the intermediate cylinder. Brightness gain is higher when the print for recycling is made on uncoated paper compared to coated, and dependent on the voltage changes. Effective residual ink concentration decreases far more on handsheets obtained from recycled samples on uncoated paper in relation to both sides coated paper. Increasing the positive voltage of intermediate cylinder and increasing the negative charge of reverse rollers increases the 3 D gamut CIE L*a*b* color cubic units. Guidelines for the size of the voltage in order to obtain optimal print reproduction are provided. The further research will include the development in area of clean technologies, advanced materials, closed loop systems; therefore the significant terms in the area of environmental sustainability.
The results from an investigation of the colour characteristic and changes in the size and shape ... more The results from an investigation of the colour characteristic and changes in the size and shape of yellow screen elements of LEP (Liquid Electrophotography Printing) prints exposed to moist-heat ageing are presented. Three sample series are analysed: prints on the non-aged paper, accelerated aged prints and prints on accelerated aged paper. The results showed that prints on the aged recycled paper and on aged fine art paper show greater colour change than aged prints on non-aged paper. The tonal values were influenced by such printing substrates on the yellow reproduction. A decrease in colour differences of prints appears on the aged offset paper used as printing substrate by increasing the screen value in area of 10%-20%. Moist-heat aged prints on offset paper influences the decrease of yellow screen elements, which is not the case for the prints made on recycled paper and those made on fine art paper. Printing on the aged paper results especially in a 30% increased reproduction of the screen elements in darker tones. On all the three paper kinds greater deviations were found along the horizontal length of the screen element in comparison to the vertical diameter length. ADDRESSES OF THE AUTHORS: Igor Majnarić ([email protected]), Ivana Bolanča Mirković ([email protected]), Zdenka Bolanča* ([email protected]), University of Zagreb, Faculty of Graphic Arts, Getaldićeva 2, 10000 Zagreb, Croatia, *Croatian Academy of Engineering, Kačićeva 28, 10000 Zagreb, Croatia Corresponding author: Ivana Bolanča Mirković
The directions of the ecological sustainability in printing reproduction are in the area of the a... more The directions of the ecological sustainability in printing reproduction are in the area of the application of the renewable and recycled raw materials, in the decrease of the energy consumption, the usage of the energy from the renewable sources and in the production without waste. This article presents the research results of voltage changes of the intermediate cylinder in indirect electrophotography with liquid toner on dirt count and area on handsheet made from fibers after prints pulping and flotation, brightness and effective residual ink concentration. Since on the indirect transfer of ElectroInk except the voltage of the intermediate cylinder also impacts temperature, its influence on the dirt count and area is showed. Uncoated and both side coated substrates were used for printing. The results show that changes in voltage of the intermediate cylinder in the printing affects the characteristics of pulped and floated fibers and dirt count and area on handsheets. Dominant factor of studied process is surface treatment of the printing substrate. Maximum efficiency of deinking flotation (87.7%) was observed on non coated paper print, at the voltage of the intermediate cylinder of 700V. The efficiency of deinking flotation on both sides coated paper prints in dependence on the voltage of the intermediate cylinder in most cases is below 10%. The results show that an increase in temperature of the intermediate cylinder increases dirt count and area on handsheetst after pulping prints under experimental conditions. Increased efficiency of flotation was found for print obtained at a lower temperature of the intermediate cylinder.
In the paper was presented the reconstruction of the printing system which was used in Senj glago... more In the paper was presented the reconstruction of the printing system which was used in Senj glagolitic press established in 1494. In the project special attention was paid to the authenticity of this historical artefact. Here is described a diagram of the flow of the process which begins with research of historical sources and collection of data, then follows the creation of technical documentation, building, testing and evaluation of a replica of the historical press. The work is completed with sketches and drawings, descriptions and explanations of the process of its creation.
The paper the results of efficiency investigation of chemical deinking of non-impact prints, wher... more The paper the results of efficiency investigation of chemical deinking of non-impact prints, where the principle of electrophotography is used for obtaining the latent image, on which the toner could adhere. The basis of scientific prepositions of deinking flotation and the mechanism for particle separation in the explanation of the results of experiment are given. The optical properties of hanh- sheets in relation to the particle separation mechanism, their size, from and structure are discussed. The results obtained by deinking flotation of a mixed sample from the prints of non-impact printing and the conventional offset printing show clearly the influence of the specific characteristic of prints techniques and the chemical composition of toner, i.e. of printing inks on the quality of recycled fibres.
Printing material and prints undergo changes during ageing which can be recognized in deteriorati... more Printing material and prints undergo changes during ageing which can be recognized in deterioration in the physical, chemical and optical properties. The aim of this work is to determine the optical changes of the prints caused by ageing of the printing material and of the prints obtained by the application of the indirect electrophotography. The change of the screen elements in lighter halftone areas, which was obtained by the usage of the microscopic image analysis, has been discussed in the article. For the preparation of samples the following papers were used: fine art paper, recycled paper and offset paper as well as black Electroink. Three sample series were observed: prints on nonaged paper and ElectroInk, prints on aged paper and ElectroInk and prints on aged paper and nonaged ElectroInk. The investigation results show that by ageing of the uncoated printing substrates the decrease of the dots on prints can be expected, while the printing on the aged paper results in the increased reproduction of the halftone dots. The obtained results are the contribution to the explanation of the influence of the accelerated ageing process of papers which are used for printing and the aged prints on the halftone dot changes. Except the mentioned determined scientific contribution the results are applicable in the area of the printing product quality as well as in the forensic science.
The aim of this paper is the result presentation of some optical properties research for ink jet ... more The aim of this paper is the result presentation of some optical properties research for ink jet prints after: exposing the prints to the mixed daylight and artificial light, exposing of prints to the sun-light through the glass window, and exposing of prints to outdoor conditions during the summer months. The prints obtained by piezoelectric and thermal ink jet technologies were used in the researches. The dye-based inks and the pigmented inks based on water and the low solvent inks were used. The results of these researches, except the scientific contribution in the domain of understanding and explaining the environmental conditions on the gamut size, i.e. the range of color tonality, colorimetric stability and print quality, can be used by the ink and paper manufacturers in new formulations, offer data for the printer producers for further production and evaluation of the position of their products.
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