This paper explains technology of Elcography which is a brand-new method of digital printing. The technology gives printed images by electro-coagulation. The volume of ink coagulation varies with time of chemical reaction between polymers and ferrous ions. Each dot can have different thicknesses. The digital image can be kept in continuous-tone mode without need of complex and time-consuming half-tone screening algorithms. The electro-coagulation reaction is very fast. The ink reacts to electricity in 4 microseconds. At a resolution of 400 dpi, the normal printing speed is 400 ft/min for 15 inch-width web.

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The development concept of MAN Roland DICO product is not only coping with the digitalization, but also is based on the challenge how the printing companies shall survive under the trend of short run length with multi-color printing. The biggest cost factor for short run printing is the cost of making plates. Therefore, the most important task of developing DICOweb was to get rid of plates from printing presses. This point is fundamentally different from other DI presses. Imaging of DICOweb adopts thermal method, utilizing CREOls 208-channel high-resolution laser head. Resolving power is max. 3200 dpi, 300 lines/inch. The imaging process is finished within 2 minutes for A4, 8 pages (4/4-color) with max. resolution. After the imaging process, the image is to be fixed on the plate cylinder sleeve with a heating device and then the conditioning process is performed so that the surface of the plate cylinder sleeve can be optimized for offset printing. These processes enable the high quality printing over 30, 000 sheets, just like conventional offset printing. The fixing and conditioning process is finished within 3 minutes for A4, 8 pages. After the printing, the image on the plate cylinder sleeve is to be erased by wiping off the image and remaining ink with a cloth, rotating the cylinder. The time required for erasing is within 3 minutes. The material of the sleeve is durable, and the use over 1, 000 times was possible in the internal test. The development concept of MAN Roland DICOweb is the challenge against the paradigms of the offset printing press. In the case of conventional offset presses, the cylinder channel gave various limitations on the machine design. On the contrary, DICOweb got rid of plates, so it became possible to apply a completely circular cylinder with sleeve technology. As the cylinder channel does not exist any longer, a high rigidity for preventing shock marks is not required, so that each cylinder could be set on the rack, where each cylinder can be moved. Thus, the cylinder diameter became changeable by changing sleeve thickness, which means that the cut off length can be changed. Further, roller marks arising from inking and dampening rollers could be removed. By the way, the web width is 300 to 520 mm and the cut off is 570 to 1260 mm. As DICOweb adopted a web-fed method, post-press finishing can be made by in-line process. Thus, the production time from the completion of pre-press data to final printing products can be shortened drastically. No plates lead to much cost reduction in the printing process, but from the viewpoint of printing machine technology, it is also very important to be able to escape from various limitations of conventional offset presses by getting rid of plates.

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Ink-jet printing, utilizing full color and high-resolution images is now easily accessible by everyone. The ink-jet printer has become a mainstream peripheral of the personal computer due to technical advances and innovations in ink-jet. As for the ink-jet printing market, big demand is expected, not only for office desktop printers but also industrial and commercial printing applications. Recently digitalization and networking have progressed rapidly in the hard copy field. Low volumes with highly variable image production is now offered to the print market. Digital on demand printing, that can print information directly through the internet, is gaining rapid and high profile attention within the print industry. Since the advent of digital on demand printing, the environment of the print industry is changing faster than ever before. The latest trend and technical hurdles of ink-jet printing are discussed.

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On the web offset printing press, special kind of ghost phenomenon is known as a kind of printing defect. This printing defect is the blurred white image showed up within the half tone image printed on the web where printing plate of the corresponding position has no such image to print. This blurred white image is suspected to be that coming from the printing plate of the other side printing. Only a little has been reported regarding this printing defect. In this paper, this special ghost phenomenon on the web offset printing was studied. We have developed a method to reproduce the ghost phenomenon and the effects of the printing condition to the ghost were examined. These results indicate that this ghost on the web offset printing occurs by two steps. First step is the ink piling on the blanket cylinder of one side reflecting the image of the other side, and the second step is the formation of the ghost on the web due to the thinning of the half tone dots at the ink piled up position. The mechanism of ink piling is suggested to be strongly related to the tack balance between top and bottom blanket cylinders and the web.

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We examine to prepare conductive carbon black (CB) dispersed systems in water with various particle concentration using humic acid sodium salt (sodium humate; HA-Na), and discuss their surface structures and viscoelasticity. The internal surface area of the CB should not be effective for viscoelasticities of the CB dispersed systems, because the average pore diameter of micropores is smaller than the average molecular diameter of HAs. These dispersed systems behave as typical elastic ones but are easy to deform. The dispersed system looks not to be fluid, but to be paste even at 1wt% of CB. It indicates that HA-Na supports the construction of 3D-network structure by CB particles and HA.

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Paper has been used for the simple media to record human information, since the paper was invented. In the mid-fifteen century, letterpress printing was invented by a German, Gutenberg. Since then, the connection between paper and printing has been very strong, and paper has been necessary to our daily life. Recently, recording data are changing from analogue to digital, and in the future, paper will be replaced by electronic media, such as “e-paper”, for some recording media. This paper presents an outline of definition, standards and some topics of printing paper.

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