Next Generation Printing Technology - Elcography (1)
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
First, Preface
The offset printing and gravure printing technologies established in the early 20th century provided a large number of means for producing printed matter at a high speed. Therefore, in a century, the important role of printing, publishing, news and broadcasting as a large-capacity media has grown up. However, the sudden changes in the social environment such as the increase in the amount of information, qualitative changes, digitization and the rapid growth of computer networks have brought about tremendous changes in the printing industry. The diversification of lifestyles in personal life, the desire for individual expression has changed the nature of the media, and the flow of information has begun to show signs of a change from the original unidirectional character to the two directions. In the printing business, the on-demand printing industry, which began to print the compiled data in the required quantity using the Internet, has started.
The printing industry to date has come as a huge equipment industry with the goal of increasing productivity. In recent years, due to the digitalization of information processing technology and the rapid development of hard copy technology, especially based on the technology cultivated by family needs and business needs, inkjet and electrophotographic methods have promoted high resolution and high speed, and sought to expand. Print on demand. In the printing market, short delivery times and small batches are also promoted, and printing machines that can achieve variable printing have emerged, digitalization of printing peripheral devices and rectification of high-speed data communication networks have prompted the realization of on-demand printing environments. Formation. As an on-demand printing machine, there are various methods such as inkjet method and electrophotographic method. The development of the prototype is still underway. This is based on the principle of electrocoagulation, and introduces the "Elcography" of the non-printing digital printing machine. Technology.
Second, develop the latitude and longitude of Elcography
Elcography started with the Canadian A.Castegnier, who was originally engaged in the photographic development business. He imagined whether it would be possible to use photographic paper to obtain photographic quality without using photographic paper. Offset printing is undoubtedly not suitable for printing one by one like a negative film. In 1971, A.Castegnier suddenly remembered the revelation gained from the visit to the gravure rotary printing factory in Paris in 1951. It was revealed that the bubbles formed by the electrolysis reaction between the electrodes of the yin and the yang were found to form a certain intaglio ink hole. As long as the ink is filled in the ink hole, it can be printed on plain paper (U.S. Patent 3,752,746). In fact, the occurrence of bubbles is very unstable, and even if the water volatilizes to solidify the gelatin layer, problems such as adhesion of electrodes are caused, and it cannot be realized as intended.
However, A.Castegnier, who has been keen on this idea, founded Elcorsy in 1981 and devoted himself to development. At that time, it was just using dye inks to print at a speed of 10 cm per second. In 1984, the basic idea of Elcography was born. It used synthetic resin colloids to initiate electrochemical condensation between the electrodes to form an image. (US Patent 4,555,320).
Since then, the printing speed has been improved, the transfer effect has been improved, and multicolorization has begun. At the NEXPO exhibition in June 1996, Elcorsy and Japan Toyo Ink Co., Ltd. published Elcography, at the IPEX exhibition in 1998. Exhibited the Model The 200Elcography press, which prints full-color variable data at 200 feet per 200 feet, and at the DRUPA show in 2000, exhibited the 400-psi Elco400Digital Press, its printing speed is divided into 400 feet. Currently, based on the Elco 400, the two companies are developing new models that improve key parts of the press.
The main features of Elcography:
1) Using water-based ink, corresponding to VOC printing method
2) High speed printing of 400 feet per minute (120 meters per minute)
3) 400 dpi resolution
4) Reproducible 256 price adjustment
Third, The principle of image formation by Elcography
The original printing is that the ink itself does not cause any chemical change from the beginning to the end of the printing process to complete the formation of the image (physical change accompanying solvent evaporation in the drying process). However, Elcography ink utilizes the principle of electrochemical resin solidification. According to the data signal, it adapts to the current intensity flowing between the yin and yang electrodes, and generates corresponding size dots to form an image. The principle of electrocoagulation is derived from the water solubility of the metal anode surface. A chemical reaction formed between a functional group of a resin (polypropylene amide) and a trivalent iron ion. The resin contains a carboxyl group and a hydroxyl group, and once it is rendered water-soluble, it is accompanied by reactivity with iron ions.
In addition to the resin, the Elco ink has a pigment for coloring, a dispersant for assisting pigment dispersion, and a chlorine salt which improves electrical conductivity.
1. Passivation layer of the anode
An electrode forming an image is formed by a metal anode covered by a passivation layer and a tip cathode disposed perpendicularly to the anode, with Elco ink filled therein (see Fig. 1).
The top of the gold-plated steel used on the anode of Elcography has a property called self-passivation, is susceptible to oxidation, and forms a thin passivation layer of several angstroms (A) which is inert to chemicals or electrons on its surface. When this layer is subjected to strong destructive damage, it is still easy to regenerate to form a new passivation layer in the presence of oxygen.
The anode of the Elcography is in the shape of a drum, spaced about 50 microns apart, and a cathode is disposed opposite the drum. As the anode drum rotates, the ink is injected into the gap between the electrodes.
2. Activation of the cathode and destruction of the passivation layer
The electrode is inert when there is no current flowing between the electrodes, and does not cause any change. Once the DC pulse is applied to the cathode corresponding to the image data, the charge induces electrolysis of the aqueous chlorine solution, and the chlorine contained in the ink locally destroys the anode surface opposite to the cathode. The passivation layer activates the anode surface. The surface of the activated non-golden steel drum should be dissolved into the ink by the amount of the trivalent iron ions pulsed (see Figure 2 and Figure 3).
3. Cohesion of resin
The eluted iron ions react with the carboxyl group of the water-soluble resin dissolved in the ink, and the pigment particles dispersed in the ink are attracted while forming a solidified body, and finally a colored dot is formed. The amount of solidified resin is proportional to the amount of eluted iron ions, and the length of the current pulse can be adjusted corresponding to the image data, so that the amount of solidified resin can be controlled.