Impact of non-uniform water absorption on water-interference print mottle in offset printing

Abstract Print mottle is a serious and yet common print defect in offset printing. An imbalance between the feed of fountain solution and the ability of the paper substrate to absorb and transport this water away from the surface can cause moisture/water interference problems. In the study presented here, we have investigated the uniformity of aqueous absorption and coating structure of pilot-coated papers with different types and dosages of dispersants and linked this to print mottle and uncovered areas (UCA). In earlier studies, the print quality of these papers indicated that a moderate addition of excess dispersant caused ink refusal, ink-lift-off (ink-surface adhesion failure) and water-interference mottle when printing at elevated fountain feed. In the present study, we have shown that a majority of the samples with uneven water/moisture absorption and an uneven burn-out reflectance tended to have more severe printing problems related to surface-moisture/water.An aqueous staining technique was used to characterise the absorption non-uniformities. This method has been developed previously with focus on absorption of flexographic water-based inks but can clearly give relevant information also for offset printing, when it comes to moisture/water interference mottle.

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Use of confocal laser scanning microscopy and a computer model to understand ink cavitation and filamentation

TAPPI Journal ◽

10.32964/tj9.10.7 ◽

2010 ◽

Vol 9 (10) ◽

pp. 7-15

Author(s):

HANNA KOIVULA ◽

DOUGLAS BOUSFIELD ◽

MARTTI TOIVAKKA

Keyword(s):

Laser Scanning ◽

Confocal Laser Scanning Microscope ◽

Laser Scanning Microscopy ◽

Confocal Laser Scanning ◽

Confocal Laser ◽

Print Quality ◽

Length Scale ◽

Offset Printing ◽

Significant Difference ◽

Printing Speed

In the offset printing process, ink film splitting has an important impact on formation of ink filaments. The filament size and its distribution influence the leveling of ink and hence affect ink setting and the print quality. However, ink filaments are difficult to image due to their short lifetime and fine length scale. Due to this difficulty, limited work has been reported on the parameters that influence filament size and methods to characterize it. We imaged ink filament remains and quantified some of their characteristics by changing printing speed, ink amount, and fountain solution type. Printed samples were prepared using a laboratory printability tester with varying ink levels and operating settings. Rhodamine B dye was incorporated into fountain solutions to aid in the detection of the filaments. The prints were then imaged with a confocal laser scanning microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip was included to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. There was no significant difference between fountain solutions with or without isopropyl alcohol on the observed patterns of the filament remains.

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The Inter-Relationship Between Paper Structure and Print Quality in Ink Jet Printing

MRS Proceedings ◽

10.1557/proc-197-309 ◽

1990 ◽

Vol 197 ◽

Author(s):

John F. Oliver ◽

A. Y. Jones

Keyword(s):

Quality Evaluation ◽

Capillary Absorption ◽

Print Quality ◽

Paper Properties ◽

Coated Papers ◽

Ink Jet ◽

The Future ◽

Jet Printing ◽

Paper Structure ◽

Potential Opportunity

ABSTRACTThis article describes a print quality evaluation of laboratory designed ink jet papers prepared on a dynamic former. A comparison with various plain and coated papers serves to illustrate the potential opportunity for papermakers to exploit novel types of paper structures in the future. The article will also briefly focus on some of the fundamental issues and key paper properties which perturb print quality and govern the capillary absorption of aqueous inks.

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Ink-lift-off during offset printing: a novel mechanism behind ink–paper coating adhesion failure

Journal of Adhesion Science and Technology ◽

10.1080/01694243.2014.989650 ◽

2014 ◽

Vol 29 (5) ◽

pp. 370-391 ◽

Cited By ~ 1

Author(s):

Hajer Kamal Alm ◽

Göran Ström ◽

Joachim Schoelkopf ◽

Patrick Gane

Keyword(s):

Offset Printing ◽

Paper Coating ◽

Coating Adhesion ◽

Adhesion Failure ◽

Lift Off

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A Brief Analysis of Vibration on the Printing Area in Ordinary Offset Press

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.591-593.2091 ◽

2012 ◽

Vol 591-593 ◽

pp. 2091-2094

Author(s):

Ming Yang ◽

Jin Yao Li ◽

Jia Cong Chen ◽

Shi Jia Kong

Keyword(s):

Product Development ◽

Noise Reduction ◽

Mechanical Vibration ◽

Practical Experience ◽

Printing Press ◽

Print Quality ◽

Offset Printing ◽

The Press ◽

Vibration Performance ◽

Printing Presses

At the development of modern printing, vibration may course some products quality problems when increases the speed. Practical experience shows that the mechanical vibration of the offset press is an important reason to affect the print quality. Therefore, improving the vibration performance of the printing press and designing the structure of anti-vibration and noise reduction to improve the quality and speed of printing presses is an important issue in the press product development. This paper proposes some reasons and solution ideas of vibration on printing parts in ordinary offset printing machines.

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Development of mathematical models of print quality by Box-Wilson

E3S Web of Conferences ◽

10.1051/e3sconf/202130403023 ◽

2021 ◽

Vol 304 ◽

pp. 03023

Author(s):

Ulbosin Eshbaev ◽

Akbarjon Nishonov ◽

Aziz Saodatov

Keyword(s):

Objective Assessment ◽

Color Perception ◽

Paint Layer ◽

Synthetic Polymers ◽

Optimal Choice ◽

Print Quality ◽

Offset Printing ◽

Before And After ◽

Static Modeling ◽

Printed Materials

The transfer coefficient of ink to the printed material was determined by comparing the mass of the printed material before and after printing. The specifics of the interaction of the printed surface with the surface of the paint layer and the influence of technological factors on the graphic distortion of the image when printing on paper also affect the gradation characteristic of the image. This article states about static modeling, preliminary analysis of the color perception of offset printing on papers including synthetic polymers. On the basis of the model of color perception obtained as a result of research in offset printing on printed materials, the optimal choice is developed, which allows to make an objective assessment and predict the color perception of the printed materials.

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Analysis of Printing Pressure Using Density Measurements of Printed Ink.

SAMRIDDHI A Journal of Physical Sciences Engineering and Technology ◽

10.18090/samriddhi.v11i01.6 ◽

2019 ◽

Vol 11 (01) ◽

pp. 39-46

Author(s):

Ramesh R Dendge

Keyword(s):

Pressure Variation ◽

Print Quality ◽

Offset Printing ◽

Qualitative Information ◽

Density Measurements ◽

Covering Material ◽

Uncoated Paper ◽

Materials Used ◽

Printing Machine ◽

Left Middle

In process-color lithographic sheet-fed offset printing the uniformity of printing pressure is critical in achieving consistent print quality. The variations in printing pressure at blanket and impression cylinder nip affect the resultant print density of process colors. The variations in printing pressure are observed not only within the print run but also in the print area of the sheet. The printing pressure is the function of machine engineering, blanket cylinder covering material, substrate, and thickness of image carrier, packing materials used in packing of blanket and plate cylinder. Many printers, even today, use a feeler gauge to judge the level of printing pressure at two or three places along with the blanket and impression cylinder nip. The conventional feeler gauge method yields qualitative information and considers a very smaller portion of the print area. In this experimental work, the densitometry is used to devise an alternative subjective method to give information about the levels of printing pressure across the print area. The image equalling print area is divided into uniformly spaced small patches and one thousand sheets uncoated paper are printed with cyan color on large format offset printing machine. Three sheets, 101th, 501th, and 901th, representing the start, middle and the end of the print run are selected. Out of each identified sheets, three patches are selected from left middle and right columns giving a total nine locations from across the print area. The reflection densities, of nine cyan patches uniformly covering the print area, are measured using electronic densitometer for each of the sheets and tabulated. This approach, involving statistics, is aimed at providing a quantitative tool to analyze printing pressure variation across the print area and within the print run.

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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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