Digital Printing Tips

Digital printing is a printing technique that uses digital information instead of traditional analog information to transfer digital image information directly to a substrate.
We generally divide digital printing into on-press imaging (Ctpress or DI) and variable image digital printing.
On-machine imaging printing: It is the process of making the plates directly on the printing press, omitting the intermediate steps (imposition, filming, printing, and loading). From the computer to the printing press is a direct process.
Heidelberg's DI46-4
The first DI printing press recognized is the Heidelberg GTO-DI, which uses laser ablation to remove the silicon layer of the graphic part to obtain the ink-receptive layer (this process is done directly on the press), after a printing It is a waterless offset press by rolling in the new version by inserting two “prints” placed inside the drum into the reject.
Man-Roland's DICO-Web (the so-called DICO is the abbreviation for Digital Change Over in English) also belongs to this type of printing press. It is a reversible printing plate cylinder device launched by Roland at DRUPA 2000. The term technology is a revolution in the printing field. It employs a laser-induced thermal imaging head to transfer the graphic elements (ink-producing layer) on the plate cylinder by transferring the color material on the "color conveyor belt". After one printing, the graphic part can be washed out, and then the next imaging and printing (this process can be repeated approximately 200 times, and then replaced with a new seamless copper sleeve).
In addition, Agfa is also testing a non-developed coating for use in thermal laser imaging, where the blank is removed by the ink path.
Since the in-process image printing technology eliminates many intermediate steps, it also reduces many unnecessary losses in the process of information transmission, and can more accurately complete the copying of images and texts than the conventional analog printing forms, and does not have to be performed during the operation. Replacing printing plates also eliminates the need for school printing, which greatly speeds up the replacement of print jobs and increases work efficiency (especially in short-run printing).
Variable data printing: Variable data printing refers to the graphics (ie, data) that need to be changed during the continuous printing process when the printing machine is not stopped. That is, the printing process can be performed without interruption. Continuous printing of different print graphic.
Electrophotography:
In the past, electrophotographic technology, which was mainly used for copying, has been widely used in the printing field. Below we briefly explain the working principle of this type of printing press by introducing several digital printing press brands that are technically representative:
Xeikon:
It provides the core of the printing for Agfa's Chromapress, IBM's InfoColor, Xerox's DocuColor, Dilpeter's DL 3300, and Man Roland's DICO series of digital presses. Its basic principle is to use light emitting diodes to form a latent image on a charged photoconductive drum. And make the toner on the plate adsorption, and then transferred to the paper, and finally to the paper to 140 °C high temperature to melt the toner, so that the toner fixed on the paper. This process is somewhat similar to the traditional copier.
Indigo
Compared with other types of variable data printers, the Indigo digital press is more like an offset press because it uses the rubber roller to indirectly transfer the ink on the plate to the paper.
It features a unique electronic ink and 100% ink transfer during the printing process. For this reason, it is also possible to print multi-color prints using only one photoconductor drum (some similar to a traditional plate cylinder) (ie, the first print of the same paper is black on the machine, and then it can be printed.) Blue, this process is continuous). Their Publisher 8000 is known as the world's highest performance digital press.
Due to many aspects of sales, Indigo has been acquired by HP, so the brand we can now see in the market is “HP Indigo”.
Xerox:
It is very similar to a traditional monochrome printer, but its interior has a CMYK four-piece drum, which is used to perform independent exposure and imaging. They rely on a transfer belt for simultaneous transfer, that is, four components. The image on the drum is transferred to the transfer belt, and the images are then transferred to the paper by static electricity and pressure.
We can discover that this is also an interesting innovation, which is rare in the brand of other printing presses.
Inkjet printing:
After a period of time, this type of printing process has made considerable progress. From the initial printing of simple bar codes and markings to the printing of large-format color prints, 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 substrates with richer materials and shapes.
According to the form of ink jet we divide it into: dro-on-demand or impruise, continuous inkjet.
Here are some simple introductions to these two types of ink jets:
Drop-on-demand (drop_on_demand): also known as pulse to ink, it is to convert the computer graphic information into a pulse of electrical signals, and then by these electrical signals to control the inkjet head closure, that is to achieve the substrate on the map Text area or blank area. Among them, the most representative ink jet technology is piezoelectric ceramic technology.
Currently, the companies that develop, design and manufacture on-demand inkjet ink heads internationally mainly include Onprion (Israel) digital company and Xaar_Barco (Belgium) company on-demand ink supply system.
Continuous inkjet (continuous inkjet): Unlike inkjet on-demand inkjet, the ink flow is continuous and uninterrupted. Under the influence of pressure, it passes through fine nozzles and disperses into small inks at high speed. drop. When each ink droplet is discharged, it is charged with static electricity. Printing on the substrate is achieved by changing the presence or absence of an electric field (if a certain point needs to be ejected, no electric force is applied to the ink droplets. Directly to the surface of the substrate; if the point does not require ink droplets, give it a deflection force of the electric field and recover it through a droplet recovery system, it can also be a reverse process, which is with the TV display The principle is very similar).
The Angela Versamark uses continuous inkjet technology.
Other Elcography, Magnctography, Bronon-Beam Imaging, Toner-Jet, and more. These technologies are gradually applied to the field of digital printing.
Since these technologies are either not mature or are not widely used, we will not introduce them here.
Here we can see that the so-called variable data printing is only a generic name for printing. It does not have a fixed model, there is no fixed core technology (compared with the traditional flat, convex, concave, and hole), almost every manufacturer There are individual innovations, and these innovations can often be said to be revolutionary. The speed of this innovation was accelerated by the involvement of computers. Due to their common characteristics (short prepress preparation time, fast conversion, etc.) they are being accepted by more printers, especially in the short-run printing market share is increasing rapidly.
At present, digital printing is mainly suitable for "print on demand" characterized by personalization, variable information, and instant, but the expensive price, the monopoly of consumables, and the printing quality of such printing are still the same as traditional printing. There is a gap in the way that the development of digital printing has been limited.