Common sense of the hottest digital printing

2022-08-15
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General knowledge of digital printing

digital printing is a printing technology that uses digital information instead of traditional analog information to directly transfer digital image information to the substrate

we generally divide digital printing into in-machine imaging printing (ctpress or DI) and variable image digital presses

in machine imaging printing: it is to take the plate making process directly to the printing machine, omitting the intermediate steps (plate making, film production, plate printing, plate loading). It is a direct process from the computer to the printing machine

Heidelberg's Di

it is recognized that the first di printer is Heidelberg gto-di. It uses laser ablation technology to remove the silicon layer of the image and text part to obtain the inkphile layer (this process is directly completed on the printer). After one printing, the machine is involved in the waste version and rolled out the new version at the same time through two "version rolls" placed inside the roller. It is a water free offset press

man Roland's DICO web (the so-called DICO is the abbreviation of digital change over in English) also belongs to this kind of printing machine. It is a reusable device for the plate cylinder launched by Roland company at the drupa 2000 exhibition. This technology is known as a revolution in the printing field. It uses a laser induction thermal imaging head to transfer the color on the "color conveyor belt" to form the image and text part (ink friendly layer) on the plate cylinder. After one printing, the graphic part can be cleaned, and then the next imaging and printing (the process can be repeated about 200 times, and then replaced with a new seamless copper sleeve)

in addition, Agfa is also testing a non developing coating used in the thermal laser imaging process, and the blank part is removed by the ink path

because in machine imaging printing technology saves many intermediate steps, it also reduces many unnecessary losses in the process of information transmission. It can complete the reproduction of images and words more accurately than the traditional analog printing form, and there is no need to replace the printing plate or calibrate the plate in the operation, which greatly accelerates the speed of replacing the printing operation and improves the work efficiency (especially in short version printing)

variable data printing: variable data printing refers to the continuous printing process that requires changing the graphics and text of printed matter (that is, the so-called data) without stopping the printing machine, that is, different graphics and text of printed matter can be printed continuously under the premise of uninterrupted printing process

electrophotographic:

electrophotographic technology, which was mainly used for copying in the past, has been widely used in the printing field. Let's briefly explain the working principle of this kind of printing machine by introducing several technically representative digital printing machine brands:

xeikon:

it provides the core part of printing for Agfa's Chromapress, IBM's infocolor, Xerox's docucolor, dilpeter's DL 3300 and MAN Roland's DICO series digital printing machines. Its basic principle is to use led to form up to 28% on the charged photoconductive drum; The first latent image of the market share of the electric tools industry, and make the toner adsorb on the printing plate, then transfer it to the paper, and finally apply a high temperature of 140 ℃ to the paper to melt the toner, so that the toner is fixed on the paper. This process is somewhat similar to the traditional copier

indigo

compared with other types of variable data printers, indigo digital printer is more like an offset press, because it indirectly transfers the ink on the printing plate to the paper with the help of rubber drum

it is characterized by the use of a unique electronic ink and 100% ink transfer in the printing process. For this reason, it can print multicolor prints with only one photoconductive drum (somewhat similar to the traditional plate cylinder) (that is, the first color of the same paper on the machine is black, and then blue, which is a continuous process). They launched publisher 8000, peek, which is called the world's highest performance digital printing machine for its degree of freedom in design

indigo has been acquired by HP due to many reasons such as sales, so the brand we can see in the market now should be "HP indigo"

Xerox:

it is very similar to the traditional monochrome printer, but it has four groups of CMYK imaging drums inside to complete independent exposure and imaging. They rely on the transfer belt for simultaneous transfer, that is, the pictures and texts on the four groups of imaging drums are transferred to the transfer belt, and then these pictures and texts are transferred to the paper through static electricity and pressure

we can find that this is also an interesting innovation, which is rare in other printing machine brands

inkjet printing:

after a period of time, this printing process has developed considerably, from printing simple bar codes and marks to printing large format color prints, and the printing quality has also been greatly improved. At the same time, because the technology it uses is pressure-free, it also determines that it can print on the surface of substrate with richer materials and shapes

according to the form of inkjet, we divide it into: dro on demand or impulse, continuous inkjet

next, we will briefly introduce these two types of inkjet forms:

drop_on_demand: also known as pulse inkjet, it converts the graphic information in the computer into pulse electrical signals, and then these electrical signals control the closure of the inkjet head, that is, to realize the graphic area or blank area on the substrate. Among them, the most representative inkjet technology belongs to piezoelectric ceramic technology

at present, the international companies that develop, design and manufacture on-demand inkjet inkheads are mainly aprion (Israel) digital company and Xaar_ Barco (Belgium) on demand inking system

continuous inkjet: different from the inkjet method of on-demand inkjet, the ink flow it ejects is continuous. Under the action of pressure, it passes through small nozzles and disperses into small ink droplets at high speed. When each ink drop leaves the ejected, it is vulnerable to temperature and electromagnetic interference (but the temperature stability of quartz crystal is good) and is charged with static charge. By changing the presence or absence of electric field, it can print on the substrate (if a point needs to be sprayed, marijn Dekkers repeatedly stated to investors in Berlin, Germany: the business department (production of transparent plastic and foam chemicals) is expected to trade ink by the end of this year, Without applying electric field force to the ink drop, it will directly reach the surface of the substrate; If there is no need for ink drops at this point, apply a deflection force of an electric field to it and recover it through an ink drop recovery system, which can also be an opposite process, which is very similar to the imaging principle of a television)

Versamark of saiangel adopts continuous inkjet technology

other

electrocoagulation imaging technology, magnctography, blectron beam imaging technology, toner jet technology, etc. These technologies are gradually applied to the field of digital printing

because these technologies are either immature or not widely used, we will not introduce more here

here we can see that the so-called variable data printing is only a general term of a kind of printing. It has no fixed mode and no fixed core technology (compared with the traditional flat, convex, concave and hole). Almost every manufacturer has its own innovation, and these innovations can usually be said to be revolutionary. The intervention of electronic computers has accelerated the speed of this innovation. Because of their common characteristics (short pre press preparation time, rapid printing conversion, etc.), they are being accepted by more printers, especially in the field of short edition printing, the market share is increasing rapidly

at present, digital printing is mainly suitable for "on-demand printing" characterized by personalization, variable information, instant, etc., but the high price, the monopoly of consumables, and the gap between the printing quality of this kind of printing and the traditional printing methods have limited the development of digital printing

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