Ink supply, water supply system uniformity

If we want to make the lithographic printer able to ink and ink balance, from the ink supply system, the water supply system, from the ink tank roller, sink roller, to the plate closest to the printing plate facing (touch plate) ink roller, there must be a very flat diameter and roller The circularity of the cylinder surface, otherwise the roller diameter is inconsistent, there is a concave defect on the roller surface, even if the best technicians want to adjust the two systems is not possible. As long as the diameter is inconsistent, the surface is dented and degraded, it will cause unevenness in the water and ink, uneven water, must be the most dry place, will not be dirty due to lack of moisture, the most humid place must be It is because there is too much water supply and it is prone to emulsification. If there is less water, it will cause a dirty spot due to insufficient water. The non-uniformity of the water roll is not limited to one mechanical dimension, but each water roll will not make the water supply system partially exposed to water or water if it is adhered to the components of the ink or ink mordant (ever water). To reduce, the situation is like the effect of water roller surface broken. The same is true of the ink roller. Diameter loss, poor roundness, and the surface is damaged to the surface of the ink roll with hydrophilic colloids. When the water is touched, it will deink. It is the same as the water supply, but the effect is reversed. Can not afford to dirty but ink fades, even in the entire ink-supply area took place without ink. Uniformity, the absence of defects on the surface, and the absence of adhesion to water or ink transfer attachments are all important conditions for the balance of ink and water.

The suitable hardness of the water roller and the ink roller and the appropriate roller pressure adjustment are also important factors for the migration of the moisture ink. Many people use the ink roller, the water roller, and even the printing roller to fully print the ink on the full version to see the touch. The width and the width of the printing press are used to determine the pressure of the cylinder. This is only relative accuracy, but it has no absolute accuracy. What is the relative accuracy? For example, the contact width of 5mm is too heavy! Adjusting to 4mm or 3mm must be light, whereas 6mm is aggravating. However, the diameter of a roller or a printing roller is different. When the roller has the same contact width, it does not mean that the pressure is the same. When the diameter is double, the contact width must be doubled to be the same. As for the small diameter contact pad, it should be exactly the same. Its reduction in its tentacles to calculate, pressure can be appropriate and not too heavy. In addition, all the rubber ink rollers and printing rollers of the lithographic printing press are arranged in a hard and soft phase, and a soft rubber roller or blanket cylinder equipped with a rubber blanket is an inner shrinkage elastic body when being pressed. These rubber-elastic, Shore Hardness values ​​also dictate the size of the pressure, as well as large contact depths or tentacles. A stiff rubber cylinder will generate a lot of pressure, a softer rubber roll or blanket and The liner produces a smaller pressure response, so the hard liner intrusion pressure can only be 0.05~0.07mm pressure, the medium hard type can have 0.12~0.15mm pressure, and the soft type liner can achieve 0.2~0.3mm intrusion pressure. Otherwise, the full version of ink transferability will be worse. As for the lack of pressure, because of poor water transmission and poor ink transmission, extremely thick layers of water and ink are required to transfer between abnormal gaps. Naturally, there is no real need for ink or water supply. Water or ink supply. If a large number of thick film ink emulsification is not normal production, not only poor ink transferability, but also easy to print on the printed pattern swell, delay drying, back printing occurs, and the dark ink, dot expansion. Many common ink rollers and water rollers are used for a long time. The roller rubber is thin due to the release of material, resulting in insufficient pressure of the ink roller and the water roller. It is necessary to do a shutdown inspection. After printing the waste plate that is no longer preserved, put down four contact plate roller or a water roller against the plate, at least check the pressure of the last pass to the plate. Can it be stored normally? After stopping the machine, press the inch forward or reverse direction to see the horizontal contact surface remnants on the roller surface. Is it right and left and the amplitude of the contact is moderate? However, this method of roll contact inside the roller does not work. Therefore, the tension amplitude method has its convenience and reference to the pressure of the printing press, but the diameter and hardness of the object to be inspected are also another reference index. If the ink roller pressure is too large, the contact width is too wide, and not only the ink transfer amount is changed, but also the ink is easily heated and softened, resulting in defects that are easy to emulsify and reduce the ink supply. Therefore, the printing plate is easily damaged and the rubber heat expands the skin. Injured problems.

The ink roller must have a lipophilic rubber to ensure that the printing ink adheres and is not easily de-inked by the adhesion of the moistened water. On the other hand, the water roller needs a softer hydrophilic rubber. If the ink roller lipophilic rubber is used, the water supply volume will be drastically reduced, and it is very easy to cause the ink to affect the amount of water supply. More importantly, the water roller is not Under the uniform ink, it is necessary to increase the amount of water, so that the minimum water supply block has enough water, then there is no water in the area, it will be too much water! Severe emulsification of the zone is produced. This non-uniformity of the upper water, which is not smooth, is not less than the deformation of the water roller diameter.

The ink roller is generally divided into two or three different rubber hardness grades, and the rubber above the ink tank roller portion and the rider roller is harder, about 35° Shore, and the ink roller of the plate is softened to reduce the impact streaks. And the head wears a smooth 28~30° Shore, others are between 30~35° Shore. The water roller uses a very soft hydrophilic rubber, about 18 ~ 22 ° Shore hardness, the water roller too hard water supply will be reduced due to the pressure becomes larger. At present, many manufacturers change the sink roller from chrome plating to sink roller on the ceramic surface. On the one hand, it can prevent the formation of chromium oxide from hindering the hydrophilicity of the chrome roller. On the other hand, the ceramic water roller keeps good and long-term hydrophilicity, and some manufacturers also have Based on this, even less IPA isopropanol alcohol is used to achieve a more environmentally friendly purpose.