Analysis of Inconsistent Printing Ink in Printing Iron

In Indian iron, the phenomenon of uneven ink color is one of the common defects of Yintie. Inhomogeneous ink is characterized by uneven ink on the entire sheet, that is, the deep part is not deep, but the light part is not light, and sometimes it is bar-shaped, sometimes into a sheet, sometimes as a dot There are many. Between printed sheets, the phenomenon of uneven ink is sometimes regular and sometimes irregular. Ink color unevenness will cause the printed iron products to lose a rich level of graphic surface, which will seriously affect the appearance quality of the printed iron products.

( China Golden Packing Network is a professional portal website of the printing and canning industry. ) In actual production, ink stick failures, dirty plates and patterns of printing plates, and inaccurate clutch pressing time of the rollers all cause ink maldistribution and even occur. Inconsistent ink density before and after printing. The occurrence of such ills will give people a feeling of imperfections in their images and images, and it will easily produce a fragmented effect. Let us analyze the factors that produce the uneven ink.

1 . Axial cores are not parallel between the rollers and the axial contact pressure is not uniform

Because the ink roller core is not parallel, the pressure is light and heavy, and the distribution of the ink in the transmission is not uniform. The thickness of the ink film transferred to the printing plate in the axial direction is inconsistent, resulting in uneven axial ink color of the printed sheet. The main reason for this is the wear of the ink roller bearing, and the looseness between the bearing and the shaft sleeve, which results in the instability of the Cui roller. The solution is to replace worn bearings, bushings, etc. so that production can proceed normally. Another reason is that the long axis of the ink roller itself is not straight, so that the pressure at each contact point is inconsistent, resulting in uneven ink.

   For the rubber roller, in addition to requiring the shaft to be straight, it is also required that the rubber roller be parallel to the shaft and straight, otherwise, the pressure of each contact point is inconsistent and the ink color is uneven. The solution is to replace the ink roller with an uneven core. In addition, when pouring the rubber roll, it is required to maintain parallelism with the axis of the shaft. For the non-parallel or non-straight rubber roller to re-grinding, serious must be re-watering.

2 . The center line of the printing roller is not parallel, the axial printing pressure is inconsistent

In the Indian iron group, the three rollers of the impression cylinder, blanket cylinder, and plate cylinder require the center line to be parallel. Non-parallel will cause the axial pressure to be inconsistent. In the imprinting process of the printing iron, the amount of ink transfer will be unequal, resulting in inconsistent printing ink shades. Most of these drawbacks have appeared on iron stamping machines that have been used for many years, especially those that have been damaged or repaired poorly. ( China Gold Packaging Network is a specialized portal site for printing and canning industry ) , and the center line is not parallel due to wear of gear parts. . In addition, the unevenness of the cushions of the plate cylinder and the blanket cylinder may also cause ink irregularities. The solution should be targeted. Repair damaged drums to make their curved surfaces clean and smooth. Replace worn gears in time. Accurately calculate the thickness of the cylinder and blanket cylinders to ensure consistent linear speeds. At the same time, the backing should be kept clean, flat, and damaged in a timely manner.

3 . Ink roller parts with low accuracy, roller body oval

The precision of the parts of the ink roller mainly refers to whether the bearing parts supporting the Crest roller are precise or not. If the support parts on both sides are not parallel to each other, the pressure at each contact point is different, and the ink color is hardly uniform. The cylinder body is elliptical and out of round and can also cause radial ink film unevenness. Generally, the iron printing plant cannot continue production after the drum of the printing machine is damaged, and immediately contact the printing equipment factory for the processing of the damage and rounding. Due to the differences in the machining levels of the equipment factories, the roundness inspection after drum body processing should be an important part of equipment acceptance. If it is found that the drum is not round and it is impossible to print iron, the equipment processing plant is required to re-process it. For the problem of the accuracy of the ink roller parts, professionals can be asked to re-test until the parallelism meets the requirements.

4 . Iron roller poor static balance performance

The inertial force is generated during rotation and the circumferential pressure of the drum changes. The reason for the poor static balance of the iron drum is excessive wear of the roller bearings, which makes the radial ink of the printing plate uneven in thickness, and the size of the printing iron pressure is different, which affects the normal transfer of the ink volume, and causes the radial density of the ink traces to be different. Device update is the fundamental way to solve the problem. Before the equipment is updated, it can be relieved by reducing the speed.

5 . Water Transfer System Adjustment Measures

In general, the water delivery system of the iron printing machine cannot distinguish the amount of water according to the density of the plates, which is determined by the mechanical characteristics of the water delivery system. Therefore, it is difficult to achieve the desired effect of ink-water balance. Under normal circumstances, the ink in the graphic-intensive areas is generally more conspicuous than that in the blank graphics. If you choose a high-precision iron printing machine or use the alcohol dampening system, this situation will be greatly improved. No matter what kind of model or what kind of dampening system, the scientific mastery of water quantity is the key to uniform ink color. For different graphics, different amounts of water should be used. If it is a graphic version with a high field value or dot density value, the ink can be appropriately enlarged; otherwise, the amount of water can be controlled appropriately. Products printed in this way will have better graphics and effects. In short, under proper pressure, the appropriate amount of water is controlled so as to achieve the balance of ink and ink in the high-speed operation of the printing iron.

6 . Drum clearance pressure release phenomenon

Due to the existence of the neutral zone between the drums of the printing machine, during the transfer process from the blanket cylinder to the printed sheets, the gap between the blanket cylinder and the plate cylinder meets and the drum body meets each other. When the neutral meets, pressure is generated due to the existence of bearing clearance. In the moment of departure, there was an immediate reduction in the pressure of printing iron. Therefore, in the production of printed iron, there are drawbacks that the prints produced after pressure are left behind due to pressure.

   In summary, the inconsistencies in the color of the Indian ink are caused by a number of factors. From the aspect of operation technology, it is necessary to maintain the ink-water balance and prevent the occurrence of ill-effects, such as floral prints, dirty prints, etc., caused by improper ink formulation, over-thinning or over-thickening. To prevent the phenomenon of imbalance of ink and ink due to the excessive amount of water and the misconstruction of syrup. Before the operation, do a good job in the cleaning and maintenance of the iron printing equipment. ( China Golden Packing Network is the professional portal website of the printing and canning industry ) Avoid ink inconsistency due to careless operation