Inking device for sheet-fed lithographic offset printing machine

First, the role of inking device

The function of the inking device is to quickly and evenly transfer the ink from the ink stripe roller output from the circumferential direction and the axial direction, so that the ink transferred to the printing plate is completely uniform and moderate in quantity. With the increase in the speed of modern offset presses, this requires that the time required for the ink to reach the printing plate from the ink fountain is shortened, and the ink-to-ink balance is faster. Therefore, when designing the inking components, it is not only necessary to determine the main technical parameters, but also to properly select the ink roller arrangement scheme.

Second, the composition of inking device

The quality of the printed matter and the structural design and manufacturing precision of the inking device are related equipment consumables. The inking units designed by the offset press manufacturers of various countries have different arrangements of rubber rollers, and their structures and degree of automation are not the same. However, in summary, the components are similar and are divided into the following three parts: ink supply parts, uniform Ink and ink sections.

Third, the inking device design requirements

In the design of the inking device, it must be comprehensively considered from the aspects of the structure, operation, and safety of the entire machine. The main requirements are as follows:

1. Stable, uniform, and proper amount when printing plates are inked.

2. The entire inking device requires less power.

3. Simple structure, reliable work and easy operation.

4. Can sensitively adjust and change the amount of ink, and ink can be adjusted steplessly.

5. There are manual or automatic independent operation buttons. The minimum time required for the inking device to stabilize is during the commissioning or startup process.

IV. Performance Evaluation Index of Ink Ink Device

The performance of inking devices is assessed in many ways, and the quality of ink supply cannot be solved from a single aspect. In the past, the design of the inking device used the method of trial and comparison to select the best solution. This method is costly and the burden on the staff is heavy. Nowadays, the design of ink inking devices generally adopts computer-aided simulation and design. This design can not only analyze the static and dynamic indicators of inking equipment, but also analyze the working status of inking equipment to find the best system. Operating parameters. The performance indicators and parameters of the inking device are mainly considered from the following aspects.

(1) The length and direction of the ink roads: The ink roads are short and long, each has its own advantages and disadvantages, but the world's major brands of offset ink roads are all developed toward the short ink road. The reason why the ink route is shortened is due to the following major improvements.

First of all, the use of simulation from the design simulation; Secondly, the quality of ink has now been greatly improved; Third, the quality of the ink roller is not only greatly improved, and in the design according to the different parameters of the model using a dedicated patent roller .

From the way of ink transmission, ink roads can also be divided into single ink roads and dual ink roads, KBA Rapida 105 is a single ink road and 162 is a dual ink road. The same model of different models of the same brand of ink road is sometimes not the same, which shows that the ink road in the design process is based on the model's structure, speed, printing format and other parameters and comprehensive consideration. It is not difficult to see from Figure 1 that the requirements for the ink path are different. Wide-format large-format models require high ink uniformity. Generally, the number of ink rollers is larger than that of the boot and the arrangement is not a single ink path.

The direction of the ink path is mainly to consider the fluidity of the ink, and the ink line generally adopts the principle of supplying the plate ink from the top down. Only when the structure is not allowed to upload ink from the bottom, such as BB type double-sided offset press. This type of ink transfer from bottom to top affects the effect of uniform ink, which can easily cause the failure of dark ink before printing. In the operation, the contact pressure of the ink roller must be appropriately increased.

With the advancement of science and technology, the inking units of many advanced offset presses use the separation and quickness of a uniform ink device: a quick start system such as the Roland 700. In the event of a failure in the printing process, the drum is pressured and the ink roller is lifted. The ink accumulated on the ink rollers continues to pass downward and accumulates on the ink roller. When the ink is reprinted, the ink appears too dark or causes Paste version. This system separates the ink path from the middle when a printing failure occurs, and disconnects the ink that is conveyed downwards, which greatly reduces the fee due to the shutdown.

(2) Inking coefficient: Offset printing machines are generally four reel-type rollers to obtain a proper inking coefficient printing market. In the design of the ink circuit, the ink paths of the first two ink rollers are short; the two back plate rollers mainly serve to uniformly coat the ink, and the last ink roller also has the function of saving excess ink. Therefore, when the ink path is designed, the ink paths of the two ink rollers are longer. If the diameter of the final reed ink roller is small, ink sticks and ghosts are likely to appear during the printing process.