One of the hottest digital printing in the world

Digital printing: there is one of the two in the world (Part 1)

in recent years, digital printing has attracted more and more attention, because the gap between pulley and column is often about (0.1 ~ 0.5) mm in different fields. I hear different people's different descriptions of it, with mixed praise and criticism. Some old-fashioned traditional printing enterprises regard themselves as hereditary aristocrats in the detailed introduction of servo hydraulic presses in the printing territory, and believe that digital printing is just a childish doll, and no matter how noisy it is, it is difficult to become a climate. Digital printing equipment suppliers have entered the printing field with great success. All kinds of equipment are shining with the charming brilliance of high technology. Their publicity is as fashionable as their styles, causing people to have a good imagination

the printing field is a geomantic treasure land, with an annual output value of hundreds of billions of yuan, and rising year by year at a double-digit growth rate. There are hundreds of printing products, and new demands are constantly put forward. Every year, many new printing enterprises are born. Whether it is the extension of the industrial chain or the new stove, they have joined the army of purchasing equipment. Under the pressure of market competition, old enterprises are also calculating the plan of equipment renewal

name of digital printing machine

traditional printing equipment includes offset printing machine, embossing machine (including flexo printing machine), gravure printing machine, silk screen printing brush machine, etc., which are generally distinguished by the type of printing plate. Later, there were also pad printing machines, inkjet printing machines, etc., which expressed the characteristics of the equipment in the form of pigment transfer. Each kind of printing equipment has its own process characteristics, which is suitable for producing different printing products. The key topics of digital printing include: the development and utilization of special processing aids and additives for special engineering plastics, the utilization and innovation of special engineering plastics in rail transit, the current situation and development trend of the utilization of special engineering plastics in the field of electronic and electrical engineering, etc. as a printing equipment, brush machine expresses its own characteristics in a way different from the way people used to in the past

the production process of traditional printed matter is customarily divided into four steps. Generally, the first is document making, including image preparation, graphic preparation, text preparation, typesetting and other processes; Followed by plate making, including output film, plate printing, etc; The third step is printing; Finally, post press processing, including finishing, folding, binding, cutting, packaging, etc. For different printing processes and printing products, the above four steps or processes will be different, such as direct cutting of folding after printing on web offset press, cutting of hardcover book block and then loading of book case, and CTP (computer to plates) plate making without outputting film, etc

the existing digital printing machine mainly completes the above two steps of plate making and printing. The process of using or not using printing plates, using water-based pigments, oil-based pigments or solid pigments, etc. are all different. Various types of equipment are collectively referred to as digital printers, which are often easy to make people fall into the fog, and are difficult to be associated with the applicability of the process. Users will feel quite difficult when purchasing digital printers. As a production-oriented professional equipment, before there is a naming standard, whether to consider adding the description of pigment category or imaging technology category in the official name of the product, such as inkjet digital printer, toner digital printer, laser digital printer, electrostatic digital printer, etc., and as a high-tech compromise to traditional habits, help users get close to and trust digital printing

the meaning of digital printing should be understood as the digitization of relevant control parameters in the printing process, or is the object processed by the printing machine a digital source? These two understandings are obviously very different. I have seen people classify all kinds of traditional printing processes as analog printing, which is juxtaposed with digital printing as two printing modes, and I still don't know what to taste carefully. As far as traditional printing is concerned, the author believes that it is against the facts and unfair. As a printing machine, no matter how it is classified and named, it is indispensable in the process of printing production. Different production processes require different characteristics of equipment. In order to understand the similarities and differences between digital printing and traditional printing, the author would like to make the following analysis with very limited professional knowledge

document preparation and color management

printing of printing products. The safety rope/safety belt detection experimental machine produced by Shandong Sida high tech factory is specially used for the pre-test preparation of safety belt tension experiment, that is, the first step of the above-mentioned printing process. This process is carried out separately outside the printing machine, and the realization of digital printing and traditional printing should be basically the same. In terms of the passing time of printing products in the production process, digital printing and traditional printing are also the same in this process. Therefore, digital printing cannot show the advantage of fast printing in this process

the regulation of the consistency between the color of prepress layout and the color of printed products needs to be completed with the help of color management system. Although conventional printing and digital printing use the same ICC system technical specifications, the relevant color space choices may be different

the consistency between the display effect of the prepress layout color and the visual effect of the printed product depends on two conditions: first, when the layout color digital quantity is converted to CIELAB chromaticity mode, the selected display color space and white dot CIEXYZ tristimulus parameters. Because sRGB color space has become the de facto standard choice of most display and digital camera manufacturers, there is generally no difference between digital printing and traditional printing in the selection of display color space; Second, when the layout color space is changed to the printing color space, the ink color space is determined and the mapping optimization algorithm is selected. Generally, the color space characteristics of inks are different from sRGB space, and the color space characteristics of different base color inks are also different. The RGB mode electronic document of the original image needs to be changed into the color separation printing mode before the plate assembly, and the color separation model should be able to be called in the plate assembly computer. The traditional printing prepress process has been based on ICC standards and software tools. The built-in color separation model of the digital printer shall be able to provide image color separation in standard format. In this regard, traditional printing shows greater flexibility. It can replace different primary color inks and use spot color inks to show the personalized effect of print color. Digital printing cannot show the personalized color effect because the primary color inks are fixed

digital printing with or without edition

electronic documents ready to be delivered for printing can be directly input into the digital printing machine to produce finished printing products. People can't see the printing process because the machine is sealed as a whole. Unlike traditional printing equipment, the transfer of substrate and ink is in an open environment. Digital printing machines can be divided into two categories if they are classified by the process of transferring pigments to the surface of the substrate. Direct injection of electronic ink on the surface of the substrate is plate free digital printing; With the help of the surface of some parts inside the equipment, the color material is transferred to the substrate for printing, which is plate printing. The choice of printing plate material of digital printing machine with plate depends on the physical process of image and text generation on the surface of printing plate. The common physical processes visible in the data can be roughly divided into three categories. The first is electrostatic imaging. The photoconductive material forms the electrostatic latent image of the graphic information of the printing page under the action of the electric field, attracts the charged solid toner or liquid toner to attach, and then transfers it to the surface of the substrate under pressure, which is similar to the electrostatic copier. The second kind of current imaging is that on the drum coated with ink layer, the DC pulse current controlled by the graphic information of the layout scans the ink drum to solidify the ink. After the uncured part of the ink is removed, it is pressurized and transferred to the surface of the substrate. The third kind of magnetic field imaging, on the surface of the drum coated with magnetic recording material, forms a magnetic field latent image under the action of a pulsed magnetic field with the graphic information of the page, and transfers the magnetic toner to the surface of the substrate for pressure transfer to complete the printing. The author calls the surface of the color material with the layout graphic information inside the digital printing machine as the printing plate, because they are the intermediates of the color material transferred to the substrate in the same principle as the printing plate in the conventional printing process. The difference between digital printing plate and conventional printing plate is that the graphic information on the same plate is variable, and the printing plate does not need to be replaced. Therefore, it is not accurate to call digital printing as plate free printing

it is well known that the film printing method used in traditional printing is difficult to accurately digitally control the graphic information on the printing plate. After CTP plate making is applied, the digital control level of pictures and texts on the printing plate is basically equivalent to that of film imaging, and is comparable to that of the internal printing plate of the digital printing machine. The digital technology of plate digital printing is easy to understand in the process of plate imaging. No matter the electric field, current and magnetic field, they can be controlled by digital quantity. The digitization of imaging pigments on printing plates is affected by many factors. Theoretically, the controlled energy on the plate surface should gather the equivalent amount of pigment, but in the actual process, the non ideal uniformity of the plate coating material, the non ideal uniformity of the pigment, the noise interference of the internal digital circuit cause the drift of the stability and consistency of the plate imaging pigment, as well as the plate wear and material aging, which will cause the transfer of the ideal value of the pigment energy calculation to actually generate the non ideal amount of the pigment on the printing plate, In addition, the non-uniformity and consistency of the substrate surface will cause the non ideal effect of the printing color to a certain extent. In this regard, compared with traditional printing, if the influence of ink quality is not considered, the main influence of ink instability and inconsistency on the printing plate is that digital printing comes from internal digital circuits, and traditional printing comes from mechanical accuracy. In this sense, the performance of digital printing should be better. However, due to the unique problem of the wear of the effective coating on the surface of the digital printing press, the service life of the printed digital printing press will be far lower than that of the traditional printing press. It is assumed that the printing plate resolution of the digital printer is equal to that of the traditional PS plate in the new machine state. Traditional printing plates are disposable, and the resolution can be considered to be stable. The resolution of digital printing machine plate decreases gradually with the increase of wear

traditional printing uses the change of half tone dot area or the change of frequency modulation dot number to show the corresponding tone change of color. The inking of the digital dot area on the printing plate and the ink transfer to the paper are completed under pressure, and the dot area on the paper is relatively increased. Due to many influencing factors, the increased area can not be directly and accurately digitally controlled, but the correlation between the printing process conditions and the full-scale dot expansion rate can be established in the statistical sense, and the lookup table between the digitized film point or printing plate point area and the actual printing point area can be completed, so as to achieve the purpose of indirect digital control of the printing color under the same process conditions. Similarly, whether half tone dots or random distribution of pigment particles are used in plate digital printing, pigment transfer is also completed under pressure, so there is also the problem that the actual printing point area is larger than the corresponding printing plate point area. If the target is to control the actual printing point area, the printing plate point can only be indirectly controlled by the look-up table established by the actual measurement data in advance, or the printing plate point area can be predicted by the look-up table. Because the relevant factors affecting dot enlargement may be different from traditional printing, the characteristic curve of dot enlargement may be different. In terms of this process, digital printing and traditional printing have the same mechanism and control technology, but only control