This issue highlights the status and application of printer status. The following are mainly selected from the industry's top printing press manufacturers such as Heidelberg, Manroland, KBA, Komori, Mitsubishi Heavy Industries and other senior engineers introduced their machines in terms of technical functions and applications. (Note: The content of this issue is collated and provided by Zhaoyang, a senior netizen of Bisheng Graphic Arts)
Heidelberg: Mr. Shao Yuanlin
1. Mechanical structure of offset printing machine
The main premise for efficient production of sheet-fed multi-color offset presses is a stable and reliable paper feeder. Therefore, all major offset press manufacturers have incorporated them into their own production systems.
At present, according to different printing materials and specifications, the paper feeding method adopted by the sheet-fed offset printing machine-step belt type standard paper feeding has vacuum suction belt type paper feeding, which has its own advantages. The reason is that it has a stable structure, and the precise paper feed and guide gauge form a right angle. In addition to the platen roller, brush and flattener, it can be widely applied to a variety of printing materials, such as corrugated paper, slightly curled paper , Which is very important for paper with unstable printing specifications and performance.
Below medium format, such as four-fold and eight-fold offset presses, suction belt conveying is used because the operation and adjustment are simple and easy.
In order to adapt to the current status of short-run jobs, that is, frequent job conversion and paper size change, Heidelberg timely introduced the preset paper feeder with higher pursuit in reliability and speed. This system retains the structure and method of the traditional step belt, but has been optimized in many aspects to make the system more compact and easy for automatic operation and control. Its characteristic is that the paper forms a precise method structure with the front and side rules. In order to ensure the reliability and speed of paper feeding; secondly, the lifting of the paper stack is stepless rather than stepwise, so that the actual thickness of the paper can be increased to maintain a stable distance from the nozzle; third, it is adopted The semi-closed system has a positive effect on noise reduction, dust prevention and maintenance-free.
In addition, for the early and late arrival of the paper in the paper feeding process, Heidelberg adopts the hem gripper speed adjustment to automatically correct within the range of 200 ° to 312 ° rotation angle instead of the traditional fixed angle.
The cylinder layout and arrangement of the printing part is one of the hot topics in the industry today. In fact, in the face of diverse and specialized market demands, both the "seven" and "five" hours have irreplaceable characteristics.
The characteristic of "Seven" o'clock is that the paper of each color group is only handed over after printing, and it is advantageous for arranging large cylinders such as double-diameter impression cylinders, which is very suitable for thick paper printing (mainly packaging printing) that requires large curvature It is beneficial, but practice shows that this method is not perfect for the publication and commercial printing based on thin paper.
The "five" o'clock method is good for better arrangements for Mo Lu.
Heidelberg follows the natural needs of market segmentation, and adopts the "seven" dot arrangement for the SM102 and CD102. Among them, SM102 is a three-cylinder (A single-diameter, double-diameter and B single-diameter) transmission and turnover system, and the rubber cylinder, impression cylinder and A single-diameter paper transfer cylinder are almost "one" shape layout, which is very conducive to printing paper Transfer (even full-page printing is very good); CD102 uses double-diameter impression cylinder and triple-diameter paper transfer cylinder as the paper transfer system, its advantages are well known.
For SM102, Heidelberg also does not use an air cushion paper guide system, but uses a metal sleeve (so-called Micro Jaket device) with ultra-fine irregular chrome-plated bumps on the surface, which is installed on the impression cylinder after printing In order to prevent the dry surface from printing and smudging under the pressure.
Heidelberg also did not use the air cushion transmission method on the anti-rubbing and scratching device printed after turning over, but adopted the silicon metal anti-rubbing film, super blue cloth and steel sleeve on the storage paper cylinder. means.
In fact, one of the focuses of the dispute between the number of cylinders and the arrangement method is the effect of paper transfer misalignment caused by different paper transfer times on the printing quality.
Heidelberg's view is that the number of paper transfers has no substantial impact on print quality. The key is to consider the accuracy of the transfer structure itself. Practice has proved the correctness of this view.
Whether to go or not to roll pillow printing should be determined according to the specific structural characteristics of the cylinder, transmission gear, bearings, etc. Judging from the current manufacturing process level of the offset press, the roller pillow printing can ensure high-quality printing, low-noise operation and the best machine durability.
Heidelberg's inking and dampening system are also very characteristic. First, it has 21 ink rollers, adopting the front vertical type (the first two ink rollers are inking, and the rear two ink rollers are inking ink). The shortest ink path is only 8 ink rollers , Can achieve rapid ink flow response.
The dampening system is a five-roller structure and has an automatic speed compensation function. Its advantage is that it can quickly realize the balance of water and ink and maintain the stability of the water supply when the printing speed changes.
When printing small-format or large-area non-image area jobs, the demand for fountain solution is less than ordinary jobs, so the water supply of the bucket roller should be reduced accordingly. Heidelberg's approach is to partition the water bucket rollers relative to the (32) ink zones, and use a row of axially adjustable blowing fans to evaporate excess dampening fluid.
The paper collection part has an important influence on the production speed of the offset press and the quality of the printed products. Heidelberg has introduced an air-blowing paper guide device, which can lead the paper into the paper stack smoothly and without scratches, and the double powder spraying device not only makes the paper stack smooth and tidy, but also saves up to 30% of powder spraying.
Second, automation and integration
The level of automation of offset presses is one of the key points of competition among manufacturers. Its development goal is to free operators from the daily and complicated manual operations, so as to focus their energies on printing quality and efficiency. There is a means of winning competition in an environment where short-run jobs are soaring.
To further improve the automation level of offset presses is based on the continuous improvement and optimization of the mechanical performance and electronic control of the machine, so as to pre-adjust the specifications of the printing materials, realize automatic monitoring and control of printing quality, and configure fully digital Electronic display system, to achieve integrated operation and management, in order to achieve better quality, shorter preparation time and reduce maintenance time, and higher output.
Heidelberg has added features such as image color control and fully automatic on-line registration control in these areas and has won praise from the industry.
In order to avoid changes in printing colors and ensure stable printing quality, Heidelberg was the first to use spectroscopic measurement technology to scan images and synchronize online color adjustments.
The on-line automatic registration and registration system not only performs rapid fine-tuning registration at the beginning of printing, but also continuously monitors and corrects the entire printing process, which can greatly reduce machine downtime and paper waste.
Integration is the future development direction of the printing industry, because printing is transforming from a simple link to a complete production process (including pre-press and post-press), and digitalization is undoubtedly the leading factor that triggered this transition.
Digitalization and integration will optimize and automate changes in information such as efficient production planning, automatic machine presetting, and capture of effective production data. The result is a further reduction in job preparation time and production time, while at the same time reaching new heights in ensuring print quality and remote service. [next]
Man Luolan: Mr. Zhang Jianfa, Director of Product Sales
1. About the structure of offset press
The paper conveying part is a part of the traditional sheet-fed offset printing machine that has more manual participation, but the modern offset printing machine has higher requirements on the accuracy and stability of paper feeding and automation in the case of high-speed multi-color printing.
In order to make the paper conveying stable and accurate, the hem-type paper delivery mechanism and the front gauge are already the mainstream of design, and the side pull gauges and paper speed changing mechanisms of various manufacturers (used to ensure that the instantaneous speed of the high-speed paper reaching the front gauge is zero) Not the same, Roland offset presses are known for vacuum paperboard, variable-speed suction belts and pneumatic side pull gauges; they use position switches to precisely control the left and right sides of the paper stack and the front and back of the paper feeder. This is especially important when the piles are uneven.
Entering the paper web thickness and other numbers into the console during preparation for prepress operations can automatically and accurately complete the precise and rapid pre-adjustment of the paper feeder, front gauge, side gauge, powder spray device and printing pressure, thereby reducing the quasi-stop time To improve production efficiency.
At present, the paper size preset function is the basic configuration of modern sheet-fed multi-color offset presses.
The printing part is the heart part of the printing machine. After years of practice and theoretical discussion, the three cylinders of the printing part are arranged at "seven o'clock", and the structure of the double diameter of the impression cylinder and the transfer cylinder is already the mainstream of multi-color offset printing machines. The double-diameter paper transfer cylinder of the impression cylinder is a "five o'clock" arrangement, such as the traditional four-boot series of several large manufacturers. The following advantages of using a double-diameter impression cylinder are well known: First, the number of paper transfers between multi-color units is reduced, so that the paper transfer error is greatly reduced; second, the paper red is printed during the impression cylinder , And then handed over to the paper transfer cylinder, so as to avoid overprint errors caused by the tail of the paper is still printing; third, due to the large curvature of the cylinder and smooth surface, it can reduce the deformation of dot transfer during imprinting.
In addition, when the offset press is worn and aging for a certain number of years, this arrangement method will not print the printed matter regardless of the thickness of the paper when printing with the largest paper width.
For the combination method of multi-color machine color, the "straight line" printing method with the flip of several major printing press plants in Germany has the characteristics of low center of gravity, good rigidity, and ink path from top to bottom, which guarantees the quality and stability of printing. It is beneficial, but each has its own solution to the problems of dirt, tearing, front and back registration, double gripping, etc. brought by the flip. The double-sided, single-sheet, double-layer, and multi-color offset presses produced by Japanese manufacturers are printed on one side. Since the ink path of the lower color group is from bottom to top, it will have an impact on the quality of the printed products and is inconvenient to maintain. Of course, it covers an area. Small is its advantage.
The ink supply system is the key to ensure the balance of water and ink and prevent some common printing failures. At present, two or three factories, including Man Roland, have adopted a fast-response ink path system, which is characterized by a small number of ink rollers (less than 16), a small diameter, good heat dissipation performance, suitable for high-speed printing, but only in the absence of water Only when the offset press and UV printing, the ink roller is circulated and cooled.
In addition, when printing prints with different contents, such as large-scale packaging prints and commercial prints with small lines and single ink colors, it is very important to produce ink at a constant speed at various speeds. Only in this way can the consistency of the supplied ink be guaranteed. To this end, Roland offset presses have a variety of programs in the ink supply cycle 1: 3: 6: 9: 18 for the initial setting to ensure the stability of printing quality.
2. About automation and auxiliary functions
In order to improve the degree of automation of sheet-fed multi-color offset presses, improve printing quality, and reduce labor, manufacturers have adopted similar pre-setting and management control systems, which will not be repeated here. Only talk about "Dynamic Automatic Registration and Registration" and "Printing Quality Inspection and Control Methods".
The dynamic automatic registration registration system has been applied to sheet-fed offset printing machines of some manufacturers, but it is not as important as the adjustment of the registration device by the tension on the web printing machine. Therefore, this system is on the sheet-fed offset printing machine The application effect has yet to be verified by practice.
As of now, Roland still insists on detecting and regulating the printing quality and its process based on the ink color density of the printed product, and has not followed the industry's publicity to use the spectrum measurement and control method. The reason is that the graphics and text of the current printed products are 2D. With some mature measurement and control strips such as Luna printing control signals, the printing quality can be detected. The spectrophotometric detection is based on the 3D detection of the spectrum. Not very practical for today's prints.
Auxiliary functions such as glazing, drying, and powder spraying are also similar. The glazing mechanism mainly includes two-roller coating and cavity blade coating. The former can quickly respond to the change of the coating amount of glazing liquid, but Not very economical; the latter, because of the use of ceramic anilox rollers, can control the coating thickness of the glazing fluid on the entire paper very accurately, and the glazing effect is flat and economical, so it is suitable for various applications. There are IR, UV and hot air drying methods, which should be selected according to the actual application. As for whether the powder is sprayed on one side or on both sides, the actual application area is not very large. [next]
Gao Bao: Mr. Wang Lianbiao, Product Leader, Beijing Representative Office
1. Mechanical structure (performance) and automation
For the feeder of modern single-sheet multi-color offset presses with speeds above 15,000 rpm, the importance is self-evident. First of all, it must be able to stably and reliably separate and transfer printing materials of different materials, widths, and thicknesses (such as paper, cardboard, plastic cards, and plastic film bases of different weights) one by one; second, to improve the degree of automation. Paper stack front-end detection, phase and skew correction, and edge gauge adjustment devices. For this reason, manufacturers have generally adopted their own high-performance paper feeders.
Up to now, several production plants have adopted vacuum suction belts for variable-speed paper transfer and precise positioning with pneumatic side pull gauges. They are especially suitable for commonly used paper media, but additional devices are required for paper jams and composite materials. For example, KBA's auxiliary press guide device is very suitable for the transport of thick paper.
To prevent paper feeding failures such as double-sheet, empty sheet, and skew, many manufacturers use photoelectric and capacitive control technologies, and KBA uses ultrasonic technology as a control method on some models, which is difficult to distinguish for some paper feeding failures, such as Thick paper, special printing materials and printing materials with thick ink on one side are very beneficial.
As the founding company of the double-diameter pressure roller and the transfer roller, the Planeta plant, one of the predecessors of KBA, has used this technology of low-curvature operation of this single-sheet multi-color offset press as early as more than 30 years ago. Our company's unit-type multi-color machine, this method has been respected and accepted by many manufacturers and evolved into some other forms.
For modern sheet-fed multi-color offset presses, whether the paper transfer cylinder is double- or triple-diameter, the gripping teeth row has a great effect, such as the double-diameter transfer roller on KAB Both rows of grippers are processed with the "cat paw" function, which saves the necessary adjustment of the row of teeth for the conversion of thick and thin paper during the printing process.
In addition, the installation of the blower and suction device of the air cushion suspension paper guide system matched with the paper transfer cylinder is also very mysterious. This is especially important when printing on thick cardboard and ultra-thin paper.
Of course, the transfer cylinder also has a function for the rapid overprinting of modern offset printing machines-it can be used as a correction for the deflection adjustment of the printing plate position, unlike the traditional unilateral deflection of the printing plate cylinder. Long-term damage to accuracy has played a positive role in the rapid response of overprinting, paper saving, and protection of machine accuracy.
Currently, only two or three production plants have this function. Several leading manufacturers of offset press production technology have their own characteristics in the design of the ink supply device for the printing part, but most of them use a multi-ink roller and double ink path for the ink delivery layout. Only KBA uses 5 on its main models. An inking system with a single ink path of different diameters depending on the plate roller. It is characterized by fewer ink rollers, only 15 rollers, and a large roller diameter. The first roller is connected to the water supply and wetting device by the roller, so that the ink and the roller are pre-emulsified, which can shorten the water-ink balance time and change the color of the printing ink. Respond quickly to reduce paper waste and cleaning time.
KBA's water supply and wetting device is also very characteristic, linear water transfer is its feature, with the use of rubber-containing water bucket roller and chrome-plated water transfer roller for continuous film water supply. This simple and fast water supply device can be used for low alcohol or alcohol free fountain solution printing without modification.
In addition, the constant temperature system of the inking device should also be the standard configuration of today's offset presses, because it can further improve the stability of the long-type live printing process, and can also do waterless offset printing to meet the future development needs of offset printing technology.
2. Accessibility and others
In addition to the online glazing and drying functions, modern offset presses also have a variety of online functions that can improve production efficiency, shorten printing cycles, save manpower expenses, and reduce intermediate storage. For example, the roll paper cutting device with vertical and horizontal cutters can be used for printing 4 + 4 color mail advertisements and newspaper supplements, punching and discharging devices, numbering mechanisms, inter-color printing devices, non-stop paper collection devices, etc. .
15,000 revolutions per hour should be the ideal rotational speed in the production of modern offset presses. At present, various manufacturers are trying to find out how to make better use of the overall benefits of the press under this printing, rather than simply increase the printing speed.
The full-sheet machine is a giant in single-sheet multi-color offset presses. Currently, only a few manufacturers are producing in the world, and only 1200mm × 1620mm specifications can be produced by KBA. The market demand for the full-sheet machine is long-term, whether in the field of commercial publishing and packaging printing, this demand is increasing, and the range of printed materials is also quite wide, including paper, cardboard, corrugated paper, etc. High-definition prints.
Meeting the needs of ergonomics, focusing on environmental protection, modern and future offset presses should be the key considerations. Because the ink, alcohol, powder spray, ultraviolet light, noise, etc. in offset printing have a considerable impact on the operator's physical and mental health and environmental protection. KBA took the lead in taking this step. At present, 105 machines have won the honor of the world's first green environmental protection machine and are named "ECOPRESS 2000". [next]
Komori: Mr. Guo Xuan and Mr. Zhao Guangye
1. Mechanical properties of offset presses
For the paper feeding part of the modern high-speed sheet-fed multi-color offset printing machine, it must not only ensure the stability and accuracy of the paper feeding during high-speed printing, but also fully consider various factors to adapt to different types and formats of printing material.
Komori's paper feeder adopts an eight-nozzle design, which can stably convey paper with a thickness of 0.04 ~ 0.8mm, while the paperboard is still a step belt. It is equipped with a movable paper brush and paper. Wheel, this arrangement also has good adaptability to printing materials that are not very standardized or of less than ideal quality.
In order to ensure the accuracy of paper feeding and prevent paper feeding failure and paper waste, Komori uses a combination of mechanical, photoelectric and inductive methods to control the skew, double and empty sheets in the paper feeding process. The paper delivery mechanism does not adopt the currently popular hem type, but is still the hem type. At present, the printer speed can reach 15,000 sheets / hour, and the paper delivery is stable and accurate. There is no such thing as unstable paper feed and printing speed, and a paper feed (forward paper) roller is also omitted. Printing can be completed in only 8 paper transfers, of course, there is a further guarantee of printing quality.
In addition, the anti-scattering tail device installed on the oscillating paper delivery shaft can compensate for the loose paper tail, which has practical significance for domestic users.
The arrangement of the printing cylinders is not important, because both the "seven" and "five" o'clock layouts have their own short and long lengths. From the actual effect, the machines with different arrangement methods have little difference in printing quality and machine operability. Moreover, there are two layouts in the product lines of some manufacturers.
The advantages of double-diameter impression cylinder and double-diameter paper transfer cylinder in ensuring the quality of printing and expanding adaptability have been proved by practice. Komori sheet-fed offset printing presses are also in this way, but the current air cushion type paper guide method is not used in the paper guide system, but a roll-over paper delivery roller with a special cloth for preventing smudging is used to ensure The printed sheets are not scratched or scratched during the transfer process.
Komori is currently the only manufacturer that has two methods of front and back printing, namely double-sided printing with flip and double-sided single-sided gripper printing, and is the only commercial manufacturer of double-sided double-sided offset printing machines. Manufacturers, this model is aimed at the color book and magazine printing market. Since 1998, this model has been installed in more than 40 units worldwide.
From the perspective of manufacturing and user use, the double-sided printing with flip in these two double-sided printing methods due to the large number of paper transfers, the accumulation of mechanical wear errors caused by long-term use will affect the quality of the printed product and is inconvenient Maintenance, secondly, there are special requirements for the quick-drying of the first four colors of ink.
The double-sided single-grip double-sided printing method, because it is a paper holding on one side, adopts the imprinting to imprinting pass-through paper method. In order to avoid the problems of dirty, mouth, positive and negative registration faced by the flip printing. In addition, this single gripping method has a strong adaptability to the domestic non-standard format paper.
The shaft, gripper structure and material on the transfer paper cylinder are important for ensuring registration accuracy, reducing ink color instability, adaptability to printing materials and durability of the printing machine. Komori uses large-diameter torsion bar teeth The shaft is used to strengthen the strength. The gripper pad adjustment device can respond quickly to thick and thin paper. The gripper is made of carbon steel coated with emery, which can greatly enhance its durability.
There should be a reason for the ink and water delivery system of the printing section, whether it is a long ink path or a short ink arrangement. Komori uses a long ink path method. Four different diameter form rollers and four ink channeling rollers provide a uniform and uniform ink film for the layout. The ink channeling roller is a copper roller, which has excellent ink transfer performance and good heat dissipation. , Easy to clean.
The water delivery system adopts a five-roller continuous water supply design with reverse water transfer. Its characteristic is that it can provide a stable, uniform and minimum amount of fountain solution directly to the layout, and it can do alcohol-free printing without changing the configuration.
The various protection devices adopted by different manufacturers in the paper collection section are designed to prevent scratches and scratches on printed products and shorten the time spent on post-printing processes. For example, the double anti-print sheet deflection device used by Komori and The de-roller (which can restore the flatness of the downward paper edge), as well as the double-receiving device that can automatically separate the faulty printed sheets.
2. Automatic control and others
For modern offset printing, its automated procedures and printing monitoring capabilities are important signs of its advanced nature.
For example, the automatic job preparation and presetting functions can quickly and accurately register and color-adjust different printing materials without relying on experience. Among them, there are two ways to adjust the diagonal of the printing plate, which are related to the structure and design of the machine itself, unlike the introduction of related materials. Komori uses the axial deflection of the plate cylinder. This is because Komori's roller bearings are processed and installed by special materials and proprietary technologies, which can adjust the deflection of ± 0.2mm while avoiding the accuracy of the cylinder. Cause long-term damage.
Sheet-fed multi-color offset presses have very high requirements for durability, because any small mechanical and electrical failures will interrupt printing and reduce production efficiency. Therefore, their ability to work overload and durability should be valued.
Judging from the current situation, the structure and design of offset presses are relatively mature. Common failures mostly occur in electrical control, but this was not the case 8 to 10 years ago. At that time, failures were mostly mechanical. Therefore, at present, all manufacturers are working hard on the stability and reliability of electrical control technology, and also applying some technical features and functional configurations of web offset presses to sheet-fed offset presses.
Komori believes that domestic offset press users' awareness of products is more focused on the scope of adaptation to thick and thin paper, the stability of offset presses, cost performance, product sales and service support, and the technological advancement of the product itself. [next]
Mitsubishi Heavy Industries: Mr. Yasuo Morita
1. Development of sheet-fed offset printing press
After years of rapid development, sheet-fed offset printing presses have become very mature in terms of mechanical structure and performance, so that the corresponding products of competitors have been difficult to form differences. To win the competition, Mitsubishi believes that sheet-fed offset printing presses must take the lead in the following three areas, including changes in paper specifications (that is, wider flexibility), higher printing quality, and increased economic efficiency by reducing waste pages.
Only in this way can the sheet-fed offset printing press survive in the gap between the future digitization wave and the importance of mass production.
The brand-new Diamond 3000 exhibited by Mitsubishi Heavy Industries at Drupa 2000 is a sheet-fed offset press that is launched in accordance with the above principles and is geared towards future market demands.
Diamond 3000 can reflect Mitsubishi's pursuit of the future of sheet-fed offset printing presses from five aspects.
1. Printing quality is higher and more stable. As far as possible, high-speed and stable production of high-quality prints is the basis of the future of sheet-fed offset printing presses.
2. Thickness and thinness are used to increase flexibility. Flexibility is one of the greatest advantages of sheet-fed offset printing presses, including the ability to print a variety of paper, cardboard and other types of printing materials, so as to meet the diversification of many printing plants. Market demand for the multi-function craving.
3. Reduce quasi-stop time and waste pages, improve production efficiency Faced with the impact of digitalization, and the frequent change of operation content caused by the more diversified demand changes in the printed product market, sheet-fed offset presses only have the level of automation control and intelligent printing Through the breakthrough, by shortening the quasi-stop time and reducing waste pages, users can challenge higher production efficiency.
4. It is the mission of the modern offset press to be fully compatible with the process of digitalization to maximize the advantages of the "accuracy" of digital data and make the offset press truly integrate into the pre-press and post-press processes.
5. Emphasizing ergonomics and the surrounding environment to consider the safety of machinery and the impact on the environment are the requirements of the entire society today, as an offset printing machine manufacturer is of course incumbent. Such efforts include improving the convenience of operation and maintenance, implementing self-diagnosis and prompting of faults, and improving the appearance of offset presses.
2. Double-sided printing and mainframe
In the development and production of double-sided flip multi-color offset presses, Mitsubishi directly adopted the popular cylinder arrangement of "seven" o'clock, as well as double-diameter impression cylinders and unique ink rollers and flip devices using ink transfer simulation technology. A 3-cylinder device is adopted, in which the paper storage roller is a double-diameter roller, which can increase the stability of the paper turning process and reduce the possibility of tearing and smudging during turning printing.
For large sheet-fed multi-color offset presses, Mitsubishi believes that from the market's current situation and development trend, the demand for large offset presses is long-term, this is because some customers want to increase production efficiency by printing on multiple sides or multiple posts at the same time .
Mitsubishi's 6F5-14000 special-purpose sheet-fed offset printing press launched in Drupa 2000 was designed to adapt to market development, with a format of 1440mm × 1040mm and a printing speed of 14000 sheets / hour.
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