Model of formation of quality of banknote production on the offset printing stage

Ink quality study have been observed on ink products in the market as a right confirmation of ink users for printint production. The study is also conducted to ensure the suitability of the ink with the printing materials and machines used by consumers. The observation was conducted on two brands of ink from the same manufacturer. The quality data studied were viscosity, spreadability, drying time, density and L*a*b. The results show that, although both inks are produced by the same manufacturer and are intended for the same market, there are differences in quality, namely one has a higher viscosity and a faster drying time than the other.Keywords—quality of printing ink, viscosity, spreadability, drying time, density and L*a*b

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Studies on Treatment of Waste Fountain Solution from Sheet-Fed Offset Printing

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.731.321 ◽

2015 ◽

Vol 731 ◽

pp. 321-324

Author(s):

Lian Fang Li ◽

Wei Min Wang ◽

Chang Xing Liao ◽

Yi Yi Zhou ◽

Jia Hao Gong

Keyword(s):

Ph Value ◽

Treatment Method ◽

Ammonia Nitrogen ◽

Second Grade ◽

Offset Printing ◽

Calcium Hypochlorite ◽

Oxidation Treatment ◽

Treatment Conditions ◽

Polyaluminium Chloride

This article explores treatment method of waste fountain solution from sheet-fed offset printing. First calcium chlorate is used to have a oxidation treatment for the waste water, then it is dealt with composite coagulants polyaluminium chloride (PAC) and cation polyacrylamide (CPAM) under different pH value. The results show that quality of the waste fountain solution could reach the national second-grade standard of sewage comprehensive discharge through the above treatment (GB 8978--1996) when treating with 0.7 g/L calcium hypochlorite and then sinking with PAC 4.0 g/L, CPAM 75.0 mg/L under the pH value of 8.0 for about 10 minutes. With the optimum treatment conditions removal rates of COD, ammonia nitrogen, phosphate and hexavalent chromium are above 90%, 94%, near to 98% and above 99% respectively.

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

Sustainability ◽

10.3390/su14010335 ◽

2021 ◽

Vol 14 (1) ◽

pp. 335

Author(s):

Marina Vukoje ◽

Ivana Bolanča Mirković ◽

Zdenka Bolanča

Keyword(s):

Oxygen Demand ◽

Offset Printing ◽

Experimental Conditions ◽

Negative Voltage ◽

Recycled Pulp ◽

Printing Technique ◽

Recycled Fibres ◽

Printing Techniques ◽

Wastewater Effluents

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.

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A Study on the Assessment of Quality of Printed Sheets in Offset Sheet-Fed Printing

JST: Engineering and Technology for Sustainable Development ◽

10.51316/jst.148.etsd.2021.31.1.9 ◽

2021 ◽

Vol 31 (1) ◽

pp. 41-45

Keyword(s):

Quality Management ◽

Total Quality Management ◽

Quality Parameters ◽

Low Density ◽

Total Quality ◽

Offset Printing ◽

Pareto Chart ◽

Printing Process ◽

Ishikawa Diagram

The quality parameters of printed sheets should be controlled constantly during the sheet-fed offset printing process. This allows the detection of any problems in the initial stages of the printing process. The final control of the quality of printing sheets will eliminate error products before delivering to the costumers. The results of this control should be analyzed continuously. The total quality management (TQM) is an effective method in controlling, doing statistics, and assessing the errors in the offset printing process. Simultaneously, this method delivers the main errors frequently occurred in the printing process. This paper presents the possibility of using some tools of the TQM method such as Pareto chart, Ishikawa diagram, and 5xWhy to analyze and assess the quality of printing sheets in sheet-fed offset printing. The studied results show that the two main errors of the printed sheets are hickeys (occupied 29 %) and low density (occupied 17%). Moreover, the causes of hickey error are analyzed and shown in this paper.

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Automatic Defect Detection for Web Offset Printing Based on Machine Vision

Applied Sciences ◽

10.3390/app9173598 ◽

2019 ◽

Vol 9 (17) ◽

pp. 3598 ◽

Cited By ~ 3

Author(s):

Erhu Zhang ◽

Yajun Chen ◽

Min Gao ◽

Jinghong Duan ◽

Cuining Jing

Keyword(s):

Image Registration ◽

Defect Detection ◽

Feature Matching ◽

Reference Image ◽

Printing Industry ◽

Offset Printing ◽

Shape Context ◽

Image Subtraction ◽

Registration Method

In the printing industry, defect detection is of crucial importance for ensuring the quality of printed matter. However, rarely has research been conducted for web offset printing. In this paper, we propose an automatic defect detection method for web offset printing, which consists of determining first row of captured images, image registration and defect detection. Determining the first row of captured images is a particular problem of web offset printing, which has not been studied before. To solve this problem, a fast computational algorithm based on image projection is given, which can convert 2D image searching into 1D feature matching. For image registration, a shape context descriptor is constructed by considering the shape concave-convex feature, which can effectively reduce the dimension of features compared with the traditional image registration method. To tolerate the position difference and brightness deviation between the detected image and the reference image, a modified image subtraction is proposed for defect detection. The experimental results demonstrate the effectiveness of the proposed method.

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Colorants in printing applications

Physical Sciences Reviews ◽

10.1515/psr-2020-0162 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Thomas Rathschlag

Keyword(s):

Current Knowledge ◽

Offset Printing ◽

Application Systems ◽

Printing Inks ◽

Letterpress Printing ◽

Flexographic Printing ◽

The Individual ◽

Printing Processes ◽

Printing Ink

Abstract This review article is a summary of the current knowledge in the field of colorants in printing applications. Printing inks belong as well as paints, coatings, plastics, and cosmetic formulations to the most important application systems for colorants, both for pigments and dyes. Colorants have to meet increasing demands in printing applications due to the considerable number of printing methods and consequently of a large number of specific printing formulations. Crucial factors besides the specific properties of a certain printing ink are the processing method and the required quality of the final printed product. Amongst the most important printing methods are letterpress printing, offset printing, flexographic printing, gravure printing, screen printing, and digital printing. Different processing methods are used for coloring of the individual printing inks. The coloring processes need to be coordinated in accordance with the steps of the printing processes leading to the final product.

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Evaluation of cut quality of woodfree coated papers

TAPPI Journal ◽

10.32964/tj12.9.9 ◽

2013 ◽

Vol 12 (9) ◽

pp. 9-15

Author(s):

BENOÎT DUFOUR, ◽

WOLFGANG BAUER ◽

JEAN-FRANCIS BLOCH

Keyword(s):

Coating Layer ◽

The State ◽

Point Of View ◽

Test Method ◽

Offset Printing ◽

Paper Properties ◽

Coated Papers ◽

Cut Quality ◽

Printing Papers

Dusting and blanket pollution are of particular interest in offset printing. Papers must be free of dust and loose particles to drastically reduce the wash interval of the blankets. Those particles are mainly generated during converting operations, such as sheeting. Considering the end-customer point of view, the visual aspect of the cut appears to be very important. To study in detail the influence of the sheeting parameters and paper properties on cut quality, a new test method to quantify the cut quality of woodfree coated papers has been developed. In particular, this method takes into consideration the state of the coating layer near the cutting edges.

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Investigation of process colours variations of electrophotography colour production presses

Proceedings - The Tenth International Symposium GRID 2020 ◽

10.24867/grid-2020-p48 ◽

2020 ◽

Author(s):

Iskren Spiridonov ◽

◽

Simeon Yordanov ◽

Rumyana Boeva ◽

Aleksandar Milkov ◽

...

Keyword(s):

Evaluation Method ◽

Calibration Method ◽

Offset Printing ◽

Internal Calibration ◽

Printing Quality ◽

Digital Production ◽

Perception Of Quality ◽

Book Covers ◽

Press Operator

In this investigation is approached method for assessing and evaluation of colour repeatability and variation for digital electrophotography printing presses. Two of most popular midlevel electrophotography colour production presses were chosen. These presses are widely used in printing houses for the printing of book covers, posters, etc. in small circulations. The similar perception of quality of digital production to the offset printing quality (ISO 12647-2:2013 ) is required from most of the clients of printing houses, publishers, etc. One of the problems of midlevel electrophotography colour production presses are variations of colours in the printing run and variations of colours during the time – weeks, months, years. The variation degree depends on many factors like – the precision of internal calibration method and types of sensors during the printing run, quality of used materials, calibration precision made by press operator, temperature and humidity variation, etc. (Kachin, Spiridonov, 2000) Specially designed for experiment test forms have been printed on two of most widely used materials for book covers, business cards, etc. – 300 g/m2 matt-coated board and 300 g/m2 offset uncoated board. The evaluation method is based on colorimetrical and densitometrical measurements (Kachin, Spiridonov, 2004) of 100 continuous printed sheets. The experiment was repeated in different time periods -between 6 hours and 4 months, to collect data for colour variation between reprinting the same test images in the time.

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Colour quality testing of CYAN offset prints depending on pigment concentration and different CTP screening mode

Proceedings - The Tenth International Symposium GRID 2020 ◽

10.24867/grid-2020-p47 ◽

2020 ◽

Author(s):

Sandra Mustač ◽

◽

Igor Majnarić ◽

Stanko Bauk ◽

Slaven Miloš ◽

...

Keyword(s):

Pigment Concentration ◽

Offset Printing ◽

High Quality ◽

Quality Testing ◽

Printing Technique ◽

Pressure Cylinder ◽

Uncoated Paper

One of the problems in the offset printing technique is the picking of uncoated paper, which occurs due to the activity of pressure cylinder and sticky offset inks. To reduce offset ink stickiness, it is possible to add cheaper ink filler that will indirectly reduce the concentration of pigment. However, there is also a reduction in the colour tones and quality of reproduction. In this experiment we used: standard cyan offset ink (Sun Lit Express ink which consists of phthalocyanine based pigment) and high-quality gloss coated cardboard (250 g/m2 Euroart plus gloss). This paper aims to show how the CTP screening type (AM/FM mode) and the CTP line screening (80, 100, 120 line/cm and 10 μm, 20 μm 25 μm diameter of print elements) manifest on the reproduction quality of a standard gradation wedge. This research will create the possibility of correlating the factors of user reduction of pigment concentration and reproduction quality of cyan colour separation. By using the AM screenings and adding different concentrations of ink filler, more stable cyan prints are achieved.

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Preventive maintenance features specific to offset printing machines

MATEC Web of Conferences ◽

10.1051/matecconf/202134308012 ◽

2021 ◽

Vol 343 ◽

pp. 08012

Author(s):

Emilia Bălan ◽

Liviu Berculescu ◽

Răzvan-George Răcheru ◽

Dorin Vasile Piţigoi ◽

Lucia Adăscăliţa

Keyword(s):

Preventive Maintenance ◽

Offset Printing ◽

Printing Process ◽

Machine Performance ◽

Continuous Quality ◽

Study Results ◽

Maintenance Activities ◽

Printing Processes

In the printing industry, where production never stops, it is very important to continuously maintain machine performance. If a machine breaks down, the production will stop and it will disturb the production process. Therefore, the maintenance system must be managed efficiently to solve those problems. The paper presents the study results on continuous quality improvement of offset printing using preventive maintenance features. Offset printing is a process that involves a multitude of variables, independent and interdependent factors. The offset printing process was analyzed and the factors that have a significant influence on the quality of the process and the products made were identified. The defects that may occur during the printing process and the causes thereof have also been identified and the types of non-conformities of the end products were estabilished. The experimental method was used. The case study was conducted on Manroland 508. For the planning of preventive maintenance activities, the duration of the maintenance works necessary to ensure the proper functioning of the offset printing machines was established. Finally, maintenance activities that would guarantee and continuously improve the quality of the printing processes and the printed products were issued.

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