At present, many exciting new processes and emerging technologies are being incorporated into web offset printing technologies. These new technologies and new processes will soon produce a shock wave that will have a great impact on the existing technologies. The new technologies presented in this article are mainly focused on conventional thermoset web offset presses. Of course, there are also some markets that will affect the cold set press.
The efficiency and productivity of future thermosetting web presses will be significantly higher, reducing prepress job preparation time, providing more stable and consistent colors, greater accuracy in registering, and even greater environmental pollution. Small, but also with the global network, remote monitoring of the operation of the printing press. To this end, printer manufacturers use a variety of related technologies to achieve these goals, including AC AC servo motors, fiber optic cable technology, almost completely enclosed thermal radiation control systems, closed-loop color control, and a range of automation features. New technologies that will soon appear include: electrostatically assisted drying, single-fluid inks, and remote diagnostics.
In the direction of non-axis printing With the continuous improvement of synchronous AC servo technology by companies such as Rexroth Indramat, printers without shafts will soon become the standard for printer manufacturers. Actually, shaftless technology is not a new thing. It appeared in the printing industry as early as two decades ago when it was mainly used to drive folding machines independently on in-line folding machines, reducing time problems. Servo motor technology has recently been applied by some manufacturers. They install a separate AC servo motor on each drive unit of the printing machine. The installation site includes: printing connectors, roll holders, cooling rollers and folds. Page machine.
Each motor is connected to a central controller via fiber optics and can be independently controlled to ensure that all units remain synchronized in terms of speed, position and torque. The KBA Compacta 215, which was exhibited at the Drupa exhibition in 1995, was the first fully-integrated shaftless press.
Shaftless presses have many advantages over traditional linear bearing presses, such as higher quality prints that can be achieved by reducing mechanical errors.
Because all units of a linear bearing press are kept in sync with the gears, chains, clutches, belts, and end-coupled pulleys. A slight backlash (caused by slight motion on the gear) at any point is transmitted to the immediately adjacent unit. The resulting mechanical error leads to premature acceleration or deceleration. These slight errors accumulate. It can cause very important problems such as color registration and web tension control. Each independent motor on the shaftless press is electrically synchronous and can be synchronized with other motors within a differential (or 0.008 degrees). Any small error will not propagate in the process and cause serious machine failure.
In addition, the shaftless press can also perform greater tension control because the speed of each unit is controlled individually. The motor driving each unit can operate at a certain percentage of the speed of the press at or above the speed of the press, with the result that higher tension control can be achieved.
WOA/WPA Rotary Offset Printing in 2001
Note: WOA (Web Offset Printing Association), WPA (Roll Paper Printing Association)
Purchase plan for the next 12 months:
Computer Direct Plate Making: 31.7%
Four-color proofing system 25.3%
Thermosetting web offset printing press: 20.3%
Saddle riding equipment 17.7%
Posting/distribution ability 15.2%
Laser imagesetter 13.9%
Circuit Board Closed Loop Color Control 10.1%
Sheetfed offset printing machine 8.9%
Condensing/Open Web Offset Press 5.1%
The best way to improve operations: (Decrease from top to bottom)
Increase the sales volume in the existing market Increase efficiency Increase the sales of new production equipment Installation of production equipment Improvement of post-press processing M&A or consolidation Improvement of pre-press improvement
Various problems faced by web offset companies: (Decrease from top to bottom)
Lack of Skilled Workers' Overcapacity or Shortages Paper Price Problems Environmental Issues Low Prices/Competitive Manufacturing Problems Digital Technology
The above is based on the "U.S. Printer" magazine's once-a-year summary of the development of the web offset printing industry. The "U.S. Printers" can be accessed from the Internet. From the Internet, it can be seen from 1999 to 2000 that WOA and WPA are in the past. , present and future perspectives.
Another important advantage of the shaftless printing press is that each printing unit can be operated independently, thereby improving the optional operation of the production. For example, one of the five-unit rotary machines is running at full speed, and then the fifth unit can be reprinted. Afterwards, the fifth unit can gradually rise to the printing speed, synchronize with other units, and start printing. In this way, each unit can operate autonomously without stopping in the middle. In addition, since the electric control device is designed and installed in the unit, the shaftless printing machine can be arbitrarily adjusted to meet the new production requirements. When a new unit is added, there is no need to increase the drive chain and connecting gears. After a new unit is tested, it can be electrically synchronized with other units on the press after installation.
Automation is greatly enhanced. Just as sheetfed printers first appeared, high-end commercial web offset presses were initially produced on a highly automated basis. When automatic registering and automatic blanket cleaning were used on rotary presses for many years, semi-automatic and fully automatic plate change has gradually become the standard for commercial web machines of various specifications. For example: The giant 64-page Heidelberg Sunday 4000 press was fully automatic when it first appeared, and manufacturers claimed that it took only 3 minutes to complete the eight-plate change. MAN Roland Lithoman of the same specification designed plate lift settings for semi-automatic plate changers to help install 79-inch-wide plates. Komori System 20 (narrow) and 38 (wide) printers also include automatic plate change technology, and Mitsubishi Diamond BTS also applies highly automated technology. In addition to changing the version, automatic feeding also makes the web press more efficient. The Heidelberg Sunday press has an automatic loading device on the web take-up device to the cutting device and operates at a speed of 150 feet per minute. Button-operated automatic and semi-automatic folding machines are also becoming more and more common, and printers such as MAN Roland Lithoman, Mitsubishi Diamond BTS and Heidelberg Sunday are installed.
All these automation devices greatly reduce the preparation time before printing, and also reduce the training time for novices. Compared with sheetfed offset presses, features such as automatic plate change, automatic register, automatic blanket cleaning, automatic paper feeding, and automatic folding and flipping increase the efficiency of web presses, while sheetfed printers print short runs. When a series of adjustments are needed, the advantages are self-evident.
Closed-Loop Color Control The original closed-loop color system emerged on Drupa 95, after more and more printer manufacturers began to provide this technology. These systems use on-line CCD recording or Combo video/spectrophotometry systems to measure optical density online. Each device can scan and measure the color mark while the machine is running, and then read the data into the ink console to compensate for ink film thickness. Companies that have used these systems have discovered that closed-loop color systems not only contribute to the consistent color quality, but are also a way to collect real-time data for static process control and guarantee customer quality. Manufacturers, including Perretta Graphic, Graphic Microsystems Inc., and QTI, have introduced closed-loop color technology to the rotating market. Many rotary printing companies are considering buying this technology. For example, Quad/Graphic invested $25 million in last year and installed closed-loop systems on all rotary presses.
An important improvement in the QTI color control system is the measurement and monitoring of gray balance data corresponding to ink film density. The principle of this system is that any color cast that affects the gray scale will cause a change in the corresponding ink film, so automatically maintaining the thickness of the ink film ensures that the hue is correct at the time of copying. Although for many printers, the QTI color control system (acquired the GATF Intertech Technology Award in 1999) is extremely expensive, it can be installed on any web offset press. The closed loop color system can largely reduce the cost and ensure a more stable print quality, so it will become a standard setting on web presses in the near future.
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