Journal of Printing Science and Technology

Special Reviews (I): Measurments and Evaluation in Printing Processes

(1) Fundamentals of Rheology Fundamental Theory of Fine Particle Suspension Stability

Kunio FURUSAWA

1993 Volume 30 Issue 2 Pages 76-83
Published: March 31, 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.76

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The present paper describes relations between the interparticle forces and their effects on the stability of fine particle suspensions. First, the classical DLVO theory of lyophilic colloid stability is summarized. The recent electrophoretic developments are also took into account. Second, the suspension stabilization, due to steric repulsion between polymer layers formed on the particle surfaces, is described in spite of the polymer layers bridging effect. And third, the basic concept of free polymer depletion effect on the suspension stability is clarified. The latter has an important role when the suspension is concentrated.

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Special Reviews (I): Measurments and Evaluation in Printing Processes

(1) Fundamentals of Rheology Suspension Rheology

Takeshi AMARI

1993 Volume 30 Issue 2 Pages 84-91
Published: March 31, 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.84

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Rheological properties of concentrated suspensions such as printing inks and organic coatings were reviewed. The suspensions show some peculiar rheological behavior. such as thixotropy, pseudo-plastic flow, rheopexy, dilatancy and other complicated non-linear viscoelastic behavior, which depend on strain amplitude, strain history, and rate of strain. On the hand equilibrium moduli in lower frequency region for the experiments of frequency dependence of the storage and loss moduli. and in longer time region for that of stress relaxation, respectively. These peculiar rheological phenomena are attributable to three dimensional flocculated structure formed by dispersed particles and the process of formation and breaking down of the flocculated structure. The flocculated structure can be considered to be responsible for the relaxation mechanisms with longer relaxation time and seems to be very sensitive to change in amplitude, rate of strain and strain history. In this review. in order to investigate the rheological properties depending on the structural networks formed by dispersed particles. effective experimental methods are introduced and peculiar rheological phenomena have been described in connection with flocculated structure and its alteration.

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Special Reviews (II): Ultra Fine Printing (1)

Limitation for Ultra-fine Printing

Hiromichi MISHINA

1993 Volume 30 Issue 2 Pages 92-98
Published: March 31, 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.92

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Press printing by means of super fine screen near 900 is challenged recently and is becoming new technical target related to printing field. This report gives a theoretical view point about technical limitation of super fine screen printing. Required limitation of screen pitch is driven from visual resolution and the structure of texture in print. The characteristic of color appearance. the requirements for dot generation on super fine screen and the related problem about image data handling and printing process control are also discussed.

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An Analysis of the Characteristics of Lightness Reproduction in Printing (Part 1)

The Relation of Reproduced Lightness and Cumulative Frequency of Original Lightness in L*

Koichi IINO

1993 Volume 30 Issue 2 Pages 99-110
Published: March 31, 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.99

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This paper presents the experimental and analytic results of the investigation in the color appearance system on the relationship of lightness between original color transparencies and their copies in offset printing. Regarding the measure of the psychometric lightness L* recommended by CIE in 1976, this study showed that the relation was non-linear, and that the characteristics of lightness reproduction correlated with the lightness cumulative frequency distributions of low psychometric chroma C* in the originals.

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An Analysis of the Characteristics of Lightness Reproduction in Printing (Part2)

Nearly Linear Relation of Original and Reproduced Lightness with Mesures in Lightness Appearance Models

Koichi IINO

1993 Volume 30 Issue 2 Pages 111-117
Published: March 31, 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.111

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This paper presents the analytic results of the investigation on the relationship of lightness between original color transparencies and their copies in offset printing. The appearance of originals under the standard viewing condition in photomechanical processes is considered to be equivalent to the appearance of their projected images under the viewing condition in a dark room. It was found in this study that the lightness relation between the originals and the copies was nearly linear in regard to the measure of the relative brightness incorporating their viewing conditions in complex field proposed by C. J. Bartleson in 1975. The meaning of this finding in tone reproduction on optical density was discussed. This relative brightness was compared with such lightness measures as proposed by C. J. Bartleson (1980) and R. W. G. Hunt (1991). The results of this study suggest to use viewing-condition-independent color for analyzing and modeling in the field of printing technology, and also for coping with the problem of color gamut compression of unprintable color.

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The Possibility of Representation of Specific Color Using Halftones of Process Ink (Part 1)

Masao MOGI, Yasuhiro SENOU, Takashi KURAMOTO, Tetsuji UTSUDA

1993 Volume 30 Issue 2 Pages 118-123
Published: March 31, 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.118

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In common practice for printing process specific color patches are used to decide the printing color. A color patch selected by a designer is separated to process color by a prepress worker's judgment. And when the color is judged unreproducible with process ink, the color is made with some inks mixing. Prepress workers must use their own judgement to determine the halftone combination that best matches to the designated color. If the color actually printed is unmatched what the designer wants, it is retouched by repetitive color matching in prepress and proof operations. This repetition causes prepress process complicated. In order to avoid the above problems, we have been studying the possibility of representation of those specific colors using halftones of process ink. Recently, we succeed to apply the following two judgments using “a parameter derived from Optical Density”.
1. Judgment of a special color can be represented using the halftones of process ink.
2. Determination of the dot percentages of yellow, magenta and cyan.
As a result, we found out that this method of utilizing “a parameter derived from Optical Density” is a practical way to solve the above problems in prepress operations.

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Erratum to : Special Reviews of Printing Materials Technology

1993 Volume 30 Issue 2 Pages 140
Published: 1993
Released on J-STAGE: September 27, 2010

DOIhttps://doi.org/10.11413/nig1987.30.140

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