Influence of Printing Technique and Printing Conditions on Prints Recycling Efficiency and Effluents Quality

Marina Vukoje,Ivana Bolanča Mirković,Zdenka Bolanča

doi:10.3390/su14010335

Marina Vukoje, Ivana Bolanča Mirković + Show 1 more

Open Access

https://doi.org/10.3390/su14010335

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Abstract

The aim of this work was to determine the influence of the conventional offset printing technique and digital electrophotography printing with liquid toner (LEP) on some optical properties of recycled fibres. A series of LEP prints was made with the variation of the negative voltage of the developing drum (−200 V, −280 V, −350 V, and −430 V) after calibration of the machine and achieving standard densitometry values. Besides deinkability aspects, the quality of wastewater effluents after process of prints recycling was observed in order to make a conclusion regarding how different printing techniques, conditions in printing process, and different types of inks can affect the wastewater effluents. Results of image analysis showed that by increasing the negative voltage of developing drum in LEP printing technique, the formation of large ink particles on handsheet from recycled pulp increases. Depending on the size of the negative voltage of the developing drum, under the same experimental conditions, handsheets made from LEP recycled fibres have lower whiteness gain, brightness gain, and ΔERIC of handsheets compared to those made from the offset prints. In addition, a certain correlation was found between IEERIC (ink elimination), chemical oxygen demand (COD), and total organic carbon (TOC) of wastewater effluents after recycling of LEP prints and offset prints as well. Organic water pollution parameters (COD and TOC) showed higher values in wastewater after recycling of offset prints compared to recycling of LEP prints.

Highlights

Sustainability approach includes energy and material flows, closed loop systems, cleaner technologies and waste reduction, and economic and social factors
The aim of this work was to determine the influence of the conventional offset printing technique and digital electrophotography printing with liquid toner on the optical properties of recycled fibres
The aim of this study was to evaluate the influence of different printing technique, conditions in printing process, and different types of inks on the efficiency of prints recycling and wastewater quality

Summary

Introduction

Sustainability approach includes energy and material flows, closed loop systems, cleaner technologies and waste reduction, and economic and social factors. European laws have proposed different strategies for the reduction of all kinds of produced waste streams, but generally waste prevention has the highest priority [2]. The printing industry consumes various amounts of raw materials resulting in generation of different types of wastes. The printing industry can be classified as a diffuse and permanent polluter, while the produced wastes are classified as solid, liquid, and gaseous wastes [3]. Waste streams from the offset printing, as the most common printing process, mainly originate from the used raw materials (printing substrates, inks, fountain solutions, metal printing plates, solvents, biocides, varnishes, and energy) [3,4,5]

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