The digitalization of prepress process is progressing, since color DTP started in late '80s in Japan. The digitalization has brought big change in graphic art industry by using database system and network. The appearance of DDCP and CTP has combined several prepress processes. And CIP4/JDF has a big possibility of changing the all printing workflow. I describe the future and now of digital workflow from a view point of total workflow, file format and application in this report.

View full abstract

The platesetter has a long history. Recently, the real operation form of platesetter and plate has almost become clear in Drupa 2000 and Print'01. The thermal type plate is becoming dominant though the plates of photopolymer type, thermal type and silver type exist together in the general market. After each plate and the optical scanning method which corresponds to it are analyzed, the plates and the platesetters of various makers who have released them in the market by now are described in this text.

View full abstract

As CTP becomes more popular, electronic prepress workflow for CEPS or DTP needs to shift to full digital prepress workflow in which all pages are composed, proofed and exposed on plates electronically. Digital proofing is one of the most important issues when we construct the full digital prepress workflow. In this paper, characteristics of digital proofing device such as sublimation dye transfer printer, ink jet printer, etc. and issues need be considered are described.

View full abstract

Various CTP (Computer-to-Plate System) plates have been developed since DURPA'95. It is getting clear that the trends of CTP are thermal and violet LD system. New no-processing plates that are available for on-press-plates, are put on the market for a few years. The recent progress of CTP plate technologies is reviewed below.

View full abstract

Thinking about the future of digital printing market, we should focus on USA market at first, because nearly a half amount of digital devices in the world are used in that market and its movement will have direct impact to us. From this point of view, firstly, you will find the suggestion from the summary of “Insight from Vision 21” written by Terry A. Nagi on the HDIA (Heidelberg Digital Imaging Association) site. He is the president of DigitalPrint Resource Inc. which evaluates Vision 21 report briefly. The formal name of Vision 21 is “Vision 21: The Printing Industry Redefined for the 21th Century” published by the cooperation of PIA and GATF. Secondly, you will find the short report of how many full color and black & white digital printing machines presented at Print '01 and how they work. I hope this short article will be of some help for you.

View full abstract

With increasing popularity of CTP, Computer to Plate, in Japan, people seem to be enjoying the practical advantage of the system. Because introduction of the system will allow them to drop some processes such as film-output and analogue plate-making process, there is a high expectation for reducing cost & delivery period. In addition, it is said that elimination of those middle processes will bring about higher quality in printed matters. Above-mentioned advantage in quality improvement assures us not only the quality improvement of usual printed matters but also the possibility of advanced printed matters with the new screening technology. This paper will introduce the new screening technologies that produce the higher quality printing with CTP.

View full abstract

As far as the printing quality is concerned, it should be recognized as the forever subject for the printing industry. Therefore, I have studied it based on the printing press as mentioned below. 1. What is the definition of printing? It processes against the draft information, and fixes it by coping on the medium (the surface of paper) from the process information with the usage of methods which make it possible for reproduction in multiple bases (Referred to a printing dictionary). 2. What is printing press? It is the total name of machinery which can make a copy in multiple bases. 3. I have handled “The unevenness of reproduction of copied information” as the measure of printing quality, and have studied the factors of quality based on the printing press as below.

View full abstract

We tried to prepare multi direct plates that can be used to many kinds of image output sources. A stable mixture solution consisting of tetraisopropyl titanate, titanium acetyl acetonate and ethanol was applied to the as -rolled aluminum surface to form water repellent film. Then we treated the film by two processes. Process 1: the organic titanium complex coated film was heat treated at temperatures above one hundred degrees and immersed in fountain solution at room temperature. Process 2: the complex coated film was immersed in phosphoric acid solution at room temperature and immersed in fountain solution. As the result, wettability with water for both samples was improved. The hydrophilic film makes non image areas of multi direct plate. We suppose that the improvement of wettability was caused by change of surface structure, not by property change generated by the change of the surface chemical composition, from measurements of FTIR and XPS, and observation of AFM.

View full abstract

There still exist ambiguous problems to be solved in the mechanism of ink transference to solid surfaces during printing process. The objective of this study is to clarify the fundamental relationship between surface free energy and ink transfer. Model ink droplets (0.1-0.2μl) of aqueous and non-aqueous types were placed by a micro-syringe on one substrate surface and attached to another surface parallel to the deposited one with the gap of 150μm. Droplets were elongated perpendicularly toward separation by adjusting computer control at constant velocities (10-70μm/sec). Cross-sectional views of liquid during the deformation process were recorded by means of video systems and analyzed to determine the transfer ratio. As the aqueous type, water and polyethylene glycol based inks were employed, and dibutyl phthalate based ink was employed as the non-aqueous type, respectively. Four types of substrates having different surface free energies were examined, namely, Al foil and three polymers, such as polyethylene terephthalate (PET), polytetrafluorethylene (Teflon) and silicone rubber. The following conclusions are obtained for the model inks combined with couples of the substrates: (1) As for the ink based on water with high polar component of surface tension, the transfer to the substrates with high surface free energy is generally unstable. In the combination of the same surfaces with very low surface free energy, the transfer seems to suffer gravitational effect, because the mostly remaining liquid on the substrates positioned low after the transfer. Also compared with the water based ink, the transfer ratio of the polyethylene glycol based ink is more stable because of the lower surface tension, and the deviation of the transfer ratio is smaller. (2) In the case where combination of the substrates is different and the difference of surface free energy is high, the water based ink transfers almost to the substrates having the higher surface free energy. As for the polyethylene glycol based ink, the transfer ratio to the polymer surfaces with the lower free energy reaches 10-20%. (3) As for the non-aqueous ink based on dibutyl phthalate with high dispersion component of surface tension, in the case where combination of substrate surfaces is the same, the transfer is mostly stable and the ratio reaches about 50%. Also in the case where each couple of the substrates is different, the transfer of 10-20% to the substrate with lower surface free energy takes place, as is different from the water based ink. (4) The effect of elongation velocity on the transfer ratio is almost negligible in the range of 10-70μm/sec. (5) The cross-sectional profiles of liquids viewed during slow deformation process are deeply related to interactive forces between liquid and substrate that are mutually due to their surface free energies. Also some findings in the viewed profiles obtained through the elongation indicate that it would be difficult for those profiles to be approximated by circular locus, as assumed by Yakhnin et al.

View full abstract

Printability of inks is one of the most important performance together with print quality and physical properties of print. The mechanism of gravure and flexo print is different. But both inks have a similar composition consisting of resins, solvent and other materials. So demanded quality about printability and various troubles happening on press are also comparatively similar. On the other hand, peculiar printability is also necessary for each ink type. Sometimes we encounter troubles caused by the differences between gravure and flexo print mechanism. In this report, we describe printability demanded generally and peculiarly for gravure and flexo ink and the design of inks for good printability. We also explain troubles and their causes of gravure and flexo print with measures to cure them.

View full abstract