How to measure and how to evaluate offset inks? The measuring methods for offset inks are classified into four categories. They are dispersion especially regarding to particle size, rheology, emulsification or water pick up and printability. The degree of dispersion is determined by using a variety of apparatus. One should evaluate it to divide into micron size and submicron size. Well known grind gauge is possible to inspect the largest particle size. Tack is a function of the force to split a thin ink film between two rollers, and is measured by inkometer. A parallel viscometer, being called spread meter, is applied to obtain flow, and also yield value. This is now computerized with video camera. A number of viscometers are applicable for offset inks with together rheometers. They don't completely defined printing phenomena on a press. Offset inks as high concentrated dispersions are required to measure thixotropy. These results would lead to analyse the structure of ink, pigment and resin selection criteria, and also elucidation printability. Emulsification or water pick up are detected dynamically by Graphometronic. Prufbau and I. G. T are widely used for printability test.

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Gravure inks are used for various purpose, and have many quality specifications. Therefor, they are evaluated with various measuring methods. This time, printability, that is one of them, is treated in outline. Measurement of printability on gravure inks is very important, because many printers require easy handling of them. In this report, gravure printing system is divided into five process, and so, printability and properties on each process are explained. Measurement of printability is mostly carried out by using printing machine, however, I think it is necessary to be establised new measuring method on physical properties, and to set up standardization in printing buisiness circles.

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Printability is one of the most important properties of paper and paperboard, as almost all of them are printed when they are used. Though it is best to test print the paper before a commercial run, it is very time and manpower consuming. This paper describes the measuring methods of paper properties that will affect the printability. Paper properties considered and discussed here are surface smoothness, compressibility, porosity and absorbency.

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Today's screen has commonly 175 lines/inch ruling for a sheet-fed offset press. Though finer screen rulings had been tried many times, actual use of them were limited only to a small size of job for special use. They have become, however, hot issues since IGAS four years before; their actual use have been reported frequently since last year. They are now moving from a trial stage to commercial use. This paper describes the advantages of the fine screen ruling as an effective mean for getting high print quality, and to show technical subjects in using them on the printing machines.

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Alkali soluble polyisoprenes modified with maleic anhydride were prepared and applied to photoresist. Various types of cis-1, 4-polyisoprenes added by maleic anhydride were prepared. Then, the addition products were esterified with methanol. Finally, an azido compound was mixed with the modified polyisoprenes. The resulted negative photoresist prepared by mixing alkali soluble polymer with bisazide could be developed by alkaline solution and showed relatively high sensitivity.

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The use of the matrix electrode on the plate cylinder and electrolyte is one of the methods for directly producing changeable lithographic image on a plate cylinder of a lithographic press. In this method, oleophilic or hydrophilic material in electrolyte is electrodeposited on the matrix electrode selectively. The electrodeposited material can be removed after printing. The authors attempted to produce an image by means of electrodepositing hydrophilic siliceous film on copper surface selectively by using sodium silicate solution as electrolyte. In this system, an image area consists of copper surface and a non-image area has hydrophilic siliceous film. As a basic research for this system, siliceous films were electrodeposited on copper surface in various sodium silicate electrolytes (SiO₂/Na₂O formula ratio: 0.5-3.1), and ink receptivity, wettability, surface roughness of the deposited films were evaluated. Hydrophilic films to which oleophilic printing ink did not adhere after dampening were produced. The quantity of the deposited film increased as SiO₂/Na₂O ratio increased. Hydrophilic film did not deposit on the copper surface immersed in the electrolyte without applying a voltage, and printing ink adhered to the surface after dampening. From the experimental results, it was found that there is possibility of producing lithographic image by means of applying a voltage on copper selectively in sodium silicate electrolyte.

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The idea of CIM (Computer Integrated Manufacturing) is recently introduced gradually in printing factory. For getting successful result on CIM and growing to higher level of ISM (Intelligent Manufacturing System) than CIM, it is required that any information and control parameter about prepress instruments, press machine, drier and forming machine are accessible and can be handled at any time. These information spread widely and contain the various characteristics of original image and/or image data and material used in the printing system and direction manuals. This paper proposes a coded system in which all characteristic parameter stated above are coded under same base. By using the proposed code system, the computer controlling the printing system can obtain any paramenter value or parameter linkage in order to calculate parameter values for initial machine operation setting and holding stable operation. The code system proposed here has also great advantage for accumulate the technical knowledge.

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I made a description of “DOT GAIN” mainly, among the troubles in offset printing, namely, judgment of “DOT GAIN”, “mechanism of appearance”, correlation of printing condition and “DOT GAIN” and also “correlation of ink and “DOT GAIN”.

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