Large Scale Printing System Color Control
Positioning Drive Regulates Color Intensity In Printing Machines
Printing machines are used to transfer information and color onto paper. Whether it be for magazines or packaging materials, speed and optimal color rendering is what really counts for modern printing facilities. The intensity of the individual colors has always been adjusted at the inking unit to achieve these optimal results. Today, automatic color zone adjusting devices facilitate work previously carried out by manual controls. Compact miniature drives, designed as motor-potentiometer-gear assemblies, are particularly well suited for such applications. These drives can be quickly installed and allow both manual adjustment from the control panel and easy, automatic adjustment of known values at the push of a button, reducing both set up time and waste volume.
Time is money, and raw materials are becoming increasingly expensive. Heidelberger Druckmaschinen, a German printing machine specialist, has minimized both of these cost factors with a new color zone adjusting system. Modern printing machines are intricately structured systems, consisting of a feeder unit for drawing in the paper, several printing units and an output unit for the finished product. Up to now, the intensity of the color print was adjusted manually using valve levers. To help automate this process, the printing machine manufacturer Heidelberger Druckmaschinen has entered into cooperation with the miniature drive expert, FAULHABER. The fruit of these efforts is a compact unit that controls color intensity either automatically or remotely from the control panel.
Depending on the specific quality demands and color requirements, five to six, and in exceptional cases up to 16 printing units are employed, with each printing unit being dedicated to a single color. The printing units can be divided into several color zones, depending on the width of the unit. In this way, the hue can be adjusted individually across the entire printing space. For normal applications between 16 and 50 "color zone" adjusting units are used for each printing unit. Miniature drives are used for coordinating and fine tuning these units with one another.
The advantage of the new system is the operator can control the process rapidly and conveniently from the control panel, and since he stands directly at the delivery point of the printing machine, he can immediately see the results of the settings that have been defined and can make any necessary changes to the hue maximum efficiency guaranteed. Once they have been set, the positioning drives ensure consistent color application throughout the entire printing run with an hourly machine output rate of up to 18,000 printed sheets.
As the miniature motors are provided with position status check-back signaling, the parameters stored for a particular order can be stored in a database. The stored values must then merely be called up for a new run and output to the color zone adjusting unit, meaning that subsequent print runs can be executed quickly and with reproducible accuracy, without any significant waste.
Compact Drive Unit
One of the key specifications was that the color zone adjusting unit should under no circumstances be larger than the current lever assembly in order for it to be accommodated in the printing unit. In a joint effort with FAULHABER, the printing machine specialists came up with a custom solution: An inexpensive, precious metal-commutated coreless DC motor, together with a plastic spur gearhead and potentiometer feedback, are assembled to form a single unit. The precious metal brushes ensure reliable, finely tuned motor startup, even after extended outages. Both the brushes and the compact power gear unit are designed for a machine lifetime and operation in ambient temperatures up to 70°C. As up to 50 color adjusting units may be required for a given application, depending on the printing unit, quick installation must also be possible in order to save time. This is ensured by simple “quick click assembly” using a spring steel plate. The motor, gearhead, and potentiometer assemblies are also equipped with prefabricated plug-in connecting cables for electrical connection to the printer control system, allowing the egg-sized drives to be quickly installed and wired.
Modern miniature drive technology allows tasks that were (until now) performed manually to be automated in a variety of sectors. Drive, control and adjustments either automated or remotely controlled by the operator no longer pose a problem. The earlier in the development process the micro motor specialist, FAULHABER and MICROMO are incorporated, the greater the likelihood of achieving more economical solutions.