Focus on inkjet printing technology (I)
(I) preface
on May 9, 2006, the annual "four new advertising exhibitions" was held at the Beijing International Exhibition Center as scheduled. At the same time, it also ushered in the grand inaugural meeting of the inkjet printing branch of China printing and equipment industry association and the first member congress. The establishment of the inkjet branch of Da Yin association indicates that the inkjet printing industry has developed to a natural time. In recent years, China's inkjet printing industry, represented by inkjet photo equipment and materials, has integrated the technical basis of it printing and inkjet printing, thus achieving rapid development. At the same time, it also indicates the arrival of the era of rapid development of inkjet printing
(II) development history of ink-jet printing
the history of ink-jet printing can be traced back to 1884. American C. h. Richard put water into the syringe and squeezed the liquid droplets flying out of the needle end. Inspired by this, if the liquid flying out is charged and controlled by electricity, a portrait can be formed on paper, which is called fog ink printing. Ink jet printing (inkjet printing) first developed in 1878. In 1951, Siemens applied for a patent for the technology of transforming liquid ink into ink droplets. At that time, due to the problems of needle and ink, the effect was poor, and it did not officially enter the practical stage until 1960
in 1964, with a special machine, the size of ink droplets and the rate of ejection can be controlled. This is the prototype of inkjet machine. Until 1967, Hertz developed a continuous inkjet printer, which is continuous ink jet printing currently used in industry. Siemens launched piezoelectric (piezoelectric) dro on demand ink jet printing in 1972, Canon launched thermal dro on demand ink jet printing in 1979, but it is called bubble ink jet printing. HP also launched thermal dro on demand ink jet printing in 1984. These are the development history of ink jet printing. 20 years ago, this technology was applied to bar code processing and product serial number printing, but the resolution was not satisfactory at that time. Until the past 10 years, the quality of inkjet printing has made rapid progress
(III) definition of inkjet printing
inkjet printing is a new printing technology without contact, pressure and plate, which can be printed by inputting the information stored in the electronic computer into the inkjet printer. It also has the common feature of plate free digital printing, which can realize variable information printing. It shoots the ink from the micro nozzle to the substrate at a certain speed, and then realizes the ink image reproduction through the interaction between the ink and the substrate
(IV) classification of inkjet printing
ink jet printing is generally divided into two categories, one is continuous (continuous) and the other is dro on demand (controllable inkjet); Continuous is mainly used in industry, such as labels, tickets, cartons and other rough surfaces, metal surfaces, and current plastic surfaces. The advantage is that the speed is fast, the smoothness of the material surface is not very important, and there is a considerable distance between the nozzle and the material, so the thickness of the printed material is not affected. The disadvantage is that the resolution is not very high, and it is usually used on rough material surfaces that do not pay much attention to the resolution, At present, continuous has developed binary deflection and multiple deflection, both of which use the principle of voltage to generate deflection. The former supplies ink according to the way of inkjet when it is charged and non inkjet when it is not charged. The latter can control the direction of deflection after the ink drops are ejected through the high-pressure deflection plate, and more accurately reach the place where inkjet is needed. The non charged ink drops are led into the ink guide tank, which can be recycled and reused
There are more than 20 ink-jet printing methods, but the basic principle is to produce small ink drops first, and then guide them to the set position. It can be roughly summarized into two types: continuous type and on-demand type. The so-called continuous inkjet is that ink droplets are generated in a continuous manner, whether the image type or non image type, and then the non image ink droplets are recycled or dispersed; On demand inkjet only produces ink droplets in the image area. Inkjet printing can be divided into black-and-white inkjet and color inkjet according to the printing color. Black and white ink-jet printing only uses single high and low temperature experimental equipment, and adopts a multi structure air supply circulation device - ink inside the body. Therefore, the machine structure and ink system are relatively simple, while color ink-jet printing is relatively complex. At present, the resolution of inkjet printing can reach 40 ink dots/mm, and the quality is close to that of photographic picturesinkjet digital printing machine is widely used. It has general-purpose models, but its speed and resolution and color reproduction area are very different according to the purpose of use. There are few suppliers of continuous inkjet digital printing machines. There are two main types of equipment, one is high-speed printing, and the other is high-quality color proofing. The reason why the number of suppliers of continuous inkjet printers is limited is that inkjet heads must be manufactured by companies that can provide complete solutions. On demand inkjet is different. There are many OEM suppliers of inkjet heads in the market. On demand inkjet heads can be manufactured in large quantities, while continuous inkjet heads are complex and difficult to produce in large quantities
(V) composition structure of inkjet printer
inkjet printer consists of system controller, inkjet controller, nozzle and substrate. Please re tension the tensioning wheel; Drive mechanism, etc. Under the control of the inkjet controller, the ink is ejected from the nozzle of the nozzle and sprayed on the substrate. According to the printing requirements, the driver transports the substrate, and the system controller is responsible for the operation of the whole machine
(VI) characteristics of inkjet printing technology
the resolution of inkjet printing is very high, and the printing quality is close to that of photos. Therefore, ink-jet printing can produce color transparent or opaque pictures, proofs of books and periodicals, newspapers and color image proofs. If the ink-jet printer is connected to the communication equipment, it can also carry out long-distance graphic transmission. As the width of ink-jet printing machine is getting wider and wider, in recent years, the use of ink-jet printing machine to produce large format prints has been widely used in advertising posters, etc., therefore, the use of ink-jet printing is becoming more and more widely
most people are used to pricing printing according to the model of how many dollars per square foot. However, the price of inkjet printing products per square foot is less than that of analog printing products. We must analyze the benefits of inkjet printing from another perspective, which is very important
first of all, inkjet technology does not provide a simple one-to-one replacement like traditional analog printing, or it can be sold like traditional printing. Inkjet brings people special opportunities. For example, it can well meet people's demand for speed, and inkjet also makes it easier to print the same pattern on different formats
in addition, with the increasing demand of customers for short print and personalized products, people are more willing to save products on CDs rather than copying or saving them on silk. The cost saved makes inkjet technology more attractive
Will silk printing disappear? Of course not. But its position in the market will change. With the continuous recognition of the value of digital printing by printing houses, the position of inkjet printing in the market will continue to be consolidated and strengthened(VII) constraints in the development of inkjet printing
although in digital printing, inkjet has a market share of about 5%. However, the development of inkjet printing is more or less restricted by some factors. At present, the main factors affecting the quality of inkjet printing are the following
1. Color conversion. How to accurately convert the color (R, G, b) of the light source system into the ink-jet or printing system (C, m, y, K) is a very complex knowledge. However, only by accurately converting the color can we obtain real and high-quality effects. Therefore, accurate color conversion technology is an important key to the quality of inkjet printing
2. Resolution. For black-and-white inkjet printers, the higher the resolution, the smaller the resolution and color scale points printed, and the better the printing quality. However, for color inkjet printers, resolution refers to how many ink dots can be printed on the width of 1 inch, regardless of whether the ink dots overlap
3. Color scale. The current ink-jet printing technology can accurately control the color level of ink drops, and control the color ink from not spraying to spraying 1 drop to spraying 16 drops at the same position
4. Print head control. Ink dots are sprayed onto the paper through the nozzle. Generally speaking, the nozzle and the letterhead are made together, so the technology of the letterhead itself is very important, and the left and right letterheads are the inkjet technology and the precision of the cantilever gear and transmission belt of the printing machine
5. Ink. Ink for inkjet printing is a special ink with moderate viscosity, which should have the properties of non-toxic, stable, non clogging nozzle, good moisture retention, good spray performance, and no corrosion to the metal components of the nozzle. At present, most inkjet inks are dye inks. The inkjet printer inks must also have sufficient surface tension to prevent the ink from splashing out when ejected. In addition, the ink must be fast drying to prevent blooming on the paper. Therefore, the ink itself is also one of the factors affecting the printing quality
6. Substrate material. Ink jet printing paper requires paper with smooth surface and a certain degree of sizing. The ink sprayed is evaporated and dried, and the ink dots are round. The printed words are clear and the graphics are beautiful. For color inkjet printing paper, it is best to have a very thin transparent coating on the surface, which can not only absorb ink quickly, but also avoid light scattering, so as to obtain ideal prints
(VIII) current situation of inkjet printing market
at present, China's self-developed and manufactured inkjet printing equipment has entered the international market, and has a good development prospect. In the face of the changes in the industrial chain within the industry and the strong demand for the development of the inkjet printing industry and market, you may have heard that inkjet printing will replace analog printing in many fields. This is true. For example, the sales volume of the U.S. wide width inkjet printing market has reached $6billion, and this market will maintain a continuous growth momentum in terms of quantity and price. This growth momentum has attracted more manufacturers to participate in competition, resulting in the increasing pressure on profits, and for printers, they must make strategic decisions immediately
in many printing plants, inkjet technology does play a complementary role to traditional printing technology because if the change-over switch is turned on "fast back". In other printing plants, the role of inkjet technology is far less than people expected. If we pay attention to the field of silk printing, we will find that the progress of science and technology has enabled people to use inkjet technology to produce a large number of live parts, so it can now compete with silk printing plants in the field of short version live parts. At the same time, direct plate making technology has effectively shortened the operation cycle of offset lithography. This forces silk printers to analyze their own business model before deciding which technology they will invest in the next step
The development and progress of inkjet and other technologies does not mean that silk printing will disappear completely. For example, although the product quality of UV ink-jet printing will reach or even exceed the level of UV silk printing, this does not mean that UV silk printing will disappear completely. The fact is, when some matureLINK
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