The ink and ink mechanism of offset presses has always been the focus of research and development by major printing machine manufacturers. An excellent system will make ink and ink control easier, and the preparation time for printing and the waste of printing materials will be greatly reduced. After years of development, the automatic ink volume control technology has been very mature. Modern printing machines mostly use automatic ink supply systems, which have also been fully affirmed worldwide. The automatic volume control system has become an offset press purchase in developed countries Must-have components. This article aims to discuss the working process and related principles of the automatic control of ink volume.
Automatic ink supply
1. Heidelberg sheet-fed offset printing press automatic ink supply system
The CIP3 file generated after the pre-press RIP records the density of each ink area on the printed sheet (now Heidelberg multi-records La, b value), which is converted into the ink volume of each color ink area by the central console, and then the inking roller injects ink on demand , To achieve automatic supply of ink.
2. Automatic supply system of manroland commercial rotary machine
Use the hydraulic principle to supply ink to the units of each printing press. The advantage of this system is that it can supply ink on demand and can be used for a long time, and the surface of the ink film does not dry, and it can supply ink to multiple printers at the same time. The ink supply principle is mainly composed of the pumping station piping system and the ink filling system. The role of the pumping station is to pump ink from the ink tank or ink tank. The function of the pipeline ink consumption metering system is to measure the ink consumption with a high-precision metering head; the ink filling system mainly guarantees the supply of ink.
Local ink supply
The ink supply system supplies ink to each printing unit through a partitioned ink fountain, and the ink supply quantity depends on the size of the graphic area of ​​the plate surface, that is: according to the area coverage of the graphic within the width of the plate ink area in the printing direction To set each ink zone. In actual operation, the ink slit width of the ink fountain ink area is adjusted by changing the rotation angle of the ink fountain screw (based on the average value of the coverage of the graphic area), and the amount of ink supply is controlled to adapt to the graphic situation of the printing plate.
The presetting of zoned ink volume has gone through an evolution process from manual adjustment to automatic adjustment. Manual adjustment is manually operated by the operator directly on the ink fountain, one unit after another, and the adjustment process is very time-consuming. In addition, the manual preset adjustment is the setting of the ink gap width of the ink area made by the operator based on the operating experience and the visual prediction of the ink amount of the ink area, and the adjustment accuracy is not high. It was not until the invention of the plate reader in 1982 that substantial progress was made in reducing print preparation time. Using the plate reader, the ink demand of each ink area of ​​the plate can be automatically measured before the plate is installed, and then the ink gap width of the ink fountain ink area can be controlled accordingly.
CPC32-CIP3, launched by Heidelberg, is an application example of the pre-press → printing → post-press digital workflow based on the CIP3 standard. CPC32-CIP3 uses PPF, a special data format for printing production, to transfer the preset data of the printing press, especially the preset data of the ink supply device.
With the promotion of JDF technology, the presetting of ink volume becomes easier and more accurate: the data of pre-press design can be directly downloaded to the printing press, and the printing press can automatically adjust the local amount of ink according to the graphic information before printing. Each ink zone has a servo drive motor, and the data obtained by the console will be transmitted to its motor. The gap between the ink fountain blade and the ink fountain roller is adjusted by the rotation of the motor to achieve local adjustment of the ink amount.
Overall ink volume adjustment
According to the actual situation of printed graphics, the amount of ink is changed as a whole. For the offset press of the ink fountain roller that rotates by gap, the ink volume is changed by adjusting the angle of the ink fountain roller. At this time, the overall adjustment of the ink volume must be manually controlled, and the angle of the ink fountain roller is determined according to the overall situation of the printed image; for continuous The rotating ink fountain roller can be adjusted by changing the rotation speed of the ink fountain roller. The rotation power of the ink fountain roller can come from the main motor or be driven by a separate servo motor.
On the one hand, the control of the overall ink volume changes the ink supply following the speed change of the host, and on the other hand, it can adjust the size of the individual trace ink volume according to the actual printed graphics. Modern offset presses basically adopt a continuous rotating ink fountain roller structure to achieve automatic ink supply.
Instrument Guitar Bag,Premium Acoustic Guitar Bag,Waterproof Acoustic Guitar Gig Bag,Waterproof Polyester Guitar Backpack
Dongguan Mingpin Traveling Appliance Company , https://www.mingpinsuitcase.com