How to improve the ink color stability of Perfume Cosmetic Boxes?

How to improve the ink color stability of Perfume Cosmetic Boxes?

At present, four-color offset presses are very popular. Heidelberg, Manroland, KBA and other well-known brand offset presses not only have excellent equipment performance and a high degree of automation, but are also equipped with an ink color remote control system, which makes the ink color control of Perfume Cosmetic Boxes more convenient and convenient. reliable. However, in the actual printing process, it is not easy to achieve stable ink color for each batch of Perfume Cosmetic Boxes. In production, there are often quality problems caused by large differences in ink color, causing great losses to the enterprise. The author has been operating Heidelberg four-color offset presses for more than 10 years. Now, I will talk about some factors that affect the stability of ink color.

Before printing, it is necessary to do pre-adjustment work based on experience

First, roughly adjust the ink volume of the ink fountains of each color group according to the area of the proofing draft or printing plate. This job is easier to do on machines with an ink-colored remote control system. There should be an estimate of more than 80% for this. Do not adjust the ink volume in a large range while printing, so as not to cause a large color difference.

Secondly, according to the requirements of the production process sheet and the characteristics of the product, all links such as feeder, delivery, ink performance, and pressure should be adjusted in advance, so as to avoid confusion during formal printing. Among them, it is the most important to ensure that the feeder can feed paper reliably, continuously and stably. Experienced operators first pre-adjust the air blow, suction, presser foot, pressure spring, press roller, side gauge, front gauge, etc. according to the width and thickness of the paper, so as to straighten out the movement cooperation between the various components. relationship, ensure that the feeder feeds the paper smoothly, and avoid the different shades of ink caused by the feeder stuttering. It is suggested here that experienced worker masters can pre-adjust the feeder.

In addition, according to the quality of the paper used for the printed product and the size of the image and text, the viscosity, fluidity and dryness of the ink should be properly adjusted in advance to improve its printability and ensure normal printing. Shut down to clean the paper wool and ink skin on the blanket and printing plate, resulting in different shades of ink. If you add various detackifiers and varnishes in the middle of printing, color deviation is certain.

In short, by doing a good job of pre-adjustment before starting the machine, the failures after the official start of printing can be greatly reduced, and the captain will have the time and energy to focus on the ink color.

Correctly adjust the pressure of water and ink rollers

During the printing process, the graphic part of the printing plate must get a continuous, uniform and appropriate amount of ink in order to obtain a printed product with the same ink color. Therefore, proper contact and rolling relationship must be maintained between the ink roller and the ink roller, and between the ink roller and the printing plate to achieve good ink transfer. If this work is not done carefully and correctly, the ink color will not be consistent. Therefore, every time the water and ink rollers are installed, the method of rolling ink bars is used to adjust the pressure between them one by one, instead of the traditional method of testing the tension with a feeler gauge, because the latter is due to various human factors. If it is larger, it should be disabled on multi-color and high-speed machines. As for the width of the ink roller, it is generally 4 to 5mm. First adjust the pressure between the ink transfer roller and the inking roller, then adjust the pressure between the inking roller and the inking roller and the printing plate cylinder, and finally adjust the water transfer roller, the plate water roller, the water series roller, and the intermediate roller. The pressure between them, as well as the pressure between the plate water roller and the plate cylinder, the ink bar between these water channels should be 6mm.

The equipment needs to be readjusted after two or three months of use, because the diameter of the ink roller will become smaller after a period of high-speed friction, especially in the transmission. The pressure between the ink rollers becomes smaller, and the ink accumulated on the ink roller will not be passed down. When the feeder stops or stops and resumes printing, due to the large amount of ink at this time, the first dozens or even hundreds of sheets are caused. The ink color is darker, and the ideal ink balance is difficult to achieve. This fault is generally not easy to find, and it is only obvious when printing finer prints. In short, the operation in this area should be meticulous and the method should be scientific, otherwise it will cause the ink color of the water, the ink stick, the mouth and the tip of the printed product to be different, which will cause artificial failure and increase the difficulty of operation.

Achieving ink balance

As we all know, ink balance is an important content in offset printing. If the water is large and the ink is large, the oil-in-water emulsification of the ink will occur, and the quality of the printed product will of course not be ideal. Through long-term practice, the author has explored some skills.

First of all, make sure that the pressure relationship between the water and the ink roller is properly adjusted, and the content of the fountain solution and isopropyl alcohol meets the general standard. On this basis, start the machine, close the water and ink rollers, and then stop to check the printing plate. Taking the amount of water at this time as the initial amount of water for printing can ensure the normal printing of general graphic products and basically realize the balance of ink and water.

Secondly, the water consumption should be flexibly adjusted according to other factors, such as the large area of the printing plate, the rough surface of the paper, the need to add additives to the ink, and the changes in printing speed, air temperature and humidity.

In addition, the author also found that when the machine just started printing, the temperature of the body was low, and when the machine was running at high speed for an hour or two, the temperature of the body, especially the temperature of the rubber roller, would more than double, or even higher. The water consumption will gradually increase until the ink reaches a new equilibrium state.

It can be seen that it is not easy to achieve the balance of ink and wash, and it requires operators to weigh and use dialectically. Otherwise, the stability of the ink color is difficult to control, and high-quality prints cannot be printed.

Proofing correction and color sequence arrangement

In production, we often encounter such a situation: the sample provided by the customer is very non-standard, or only a color spray draft is provided without proofing. At this time, the specific situation should be analyzed in detail, and the effect of the proofing draft cannot be chased by rigidly increasing or reducing the amount of ink. Even if it is close to the proofing draft at the beginning, the stability of the ink color cannot be guaranteed, so the final quality of the printed product cannot be guaranteed. In this regard, the printing factory should actively exchange opinions with the customer in a serious and responsible attitude, point out the problems existing in the sample draft and make suggestions for revision, and then make appropriate adjustments and re-printing after obtaining the approval.

In production, the ink viscosity is usually used to determine the printing color sequence of the multi-color machine. In multi-color printing, the inks are overprinted together in a wet-on-wet manner. Only by obtaining the best overprinting rate can the ink color be stable and printed. Consistent print. The arrangement of the printing color sequence must obey the characteristics and quality requirements of the printed product, and cannot be static. At the same time, the ink viscosity can also be adjusted. For example, a cover dominated by purple and a cover dominated by sky blue have different printing color sequences. The former is first cyan and then magenta, and the latter is first magenta and then cyan. Otherwise, the superimposed colors will be speckled. , neither uniform nor unstable. Such as black-based prints, black should be arranged in the last color group as much as possible, so that the Perfume Cosmetic Boxes have better black gloss and avoid the occurrence of scratches and color mixing inside the machine.

Develop good operating habits and strengthen work responsibility

Doing any job must have a high sense of responsibility and a strong sense of quality, must standardize process operations, and adhere to good traditional habits such as "three levels" and "three diligence". Taking the proofs frequently as an example, when comparing the signature samples on the template, due to differences in distance, angle, light source, etc., the vision will be deviated, resulting in inconsistent ink colors. At this time, the signature must be removed from the template and compared carefully The long version of the live printing plate needs to be baked to reduce the ink color deviation caused by the plate change; the blanket should be cleaned frequently, and more blotting paper should be placed after each cleaning to stabilize the ink color; The five or six sheets of ink that have just been printed are too dark to be pulled out. The printing speed should not be too fast. The important thing is to keep the machine stable and normal; when adding ink to the ink fountain, because the new ink is hard and has poor fluidity, it needs to be stirred a few times. , so as not to affect the ink volume and cause ink color deviation.

Operators should continue to learn, observe and analyze carefully, find out the factors that affect the change of ink color from all aspects, and take corresponding measures to properly prevent and overcome them, strive to improve the stability and consistency of ink color of Perfume Cosmetic Boxes, and effectively improve Perfume Cosmetic Boxes. quality.

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