1.Human Factors

    Employees' lack of good professional ethics and sense of responsibility is one of the reasons for many major quality accidents. In order to ensure the quality of gravure printing, the professional ethics education of employees should be strengthened, and job awareness should be strengthened; employees are required to be proficient in the use and operating procedures of equipment.

    2. Machine factor

    In gravure printing, the equipment problem that causes unclear graphics and text is mainly that some related devices are not fully equipped or even if they are equipped, they are not well used. These devices mainly include the following.

    A. Ink circulation device. The printing equipment of many companies is not equipped with ink circulation devices, and the ink is directly added to the ink tray, which causes insufficient circulation of the ink and poor fluidity, resulting in unclear printing and unclear printing. Ink circulation devices include motor-type ink circulation devices and pneumatic pump-type ink circulation devices. The price of the motor type is lower, but the foreign matter in the ink will block the filter of the ink outlet slot and the ink will not be loaded on the tray, resulting in deinking. The initial amount of ink is large, which is easy to cause waste of ink. The air-pump type has a small amount of ink for the first time, which can reduce ink waste, and it is rare for foreign matter in the ink to block the filter and cause fires due to overheating of the motor, which has high safety.

    B. Swing device for ink scraper. In order to extend the service life of the scraper, some companies often remove the left and right swinging device of the scraper. This will not only cause failures such as unclear graphics and text, but also shorten the service life of the plate cylinder.

C. Circulating water cooling device. The main function of the circulating water cooling device is to quickly cool down the printed matter after leaving the oven, so as not to produce anti-sticking phenomenon and the phenomenon of mutual sticking between the front and back of the printed matter after rewinding. Because of its high cost, many printing companies often do not have equipment when introducing equipment. There are two direct consequences of doing so.

One is that with the long-term operation of the equipment, the temperature of the first guide roller after the printed product passes through the oven rises quickly. When the temperature rises to a certain level, the resin in the ink is burned, resulting in anti-sticking phenomenon , The printed graphics are not clear.

The second is that the ink or varnish on the printed matter enters the winding device without being completely dried, and when it is unfolded, the front and back sides will stick together, which will also cause the printed graphics and text to be unclear. In order to reduce the unclear printing of graphics and text, it is recommended that you equip the above devices in time.

     3. Material factors

     The main materials that affect printing quality are: printing materials, inks, solvents and rubber rollers.

     A. Printing materials. Printing materials include plastic, paper, aluminized paper and aluminum foil. Our company mainly prints aluminum foil and aluminized paper. Poor surface treatment of aluminum foil and excessive oil stains will make the transfer performance of the ink worse, resulting in unclear printing graphics; while the aluminum-plated paper has a poor aluminum plating effect, the surface is uneven, and the printed matter will produce many bright spots, and the graphics are natural. Not clear.

     B. Ink. Ink viscosity, fineness, yield value, thixotropy, fluidity, adhesion and other quality indicators that do not meet the printing requirements will affect the transfer of the ink on the printing material, resulting in unclear print graphics. In addition, too much impurity content in the ink will also affect the clarity of printed images. When the old ink is put on the machine, it should be filtered, and a certain amount of new ink should be added, and replaced with new ink if necessary.

     C. Solvent. The purity of the solvent is low, and it contains too much grease or water, which will inevitably not be conducive to the full dissolution of the ink, resulting in impure print hue and unclear and full printed graphics.

     D. Plate cylinder. For gravure printing, the number of screen lines of the printing plate cylinder, the shape and depth of the cells, the quality of the chrome-plated layer, and the quality of the surface polishing process will directly affect the ink transfer rate in the cells. The ink transfer rate is low, and the printed graphics are not clear.

    4.Method factors
    The proficiency of the operating skills, the correctness of the operating methods, and whether the operating procedures are strictly followed have an important impact on the quality of the printed matter. In summer, the temperature is higher, and the solvent volatilizes faster. At this time, it is necessary to reduce the angle of the scraper as much as possible, shorten the distance between the scraping point and the imprinting point, reduce the volatilization of the ink solvent on the plate, and reduce the occurrence of blockage. When the solvent volatilization rate is slow in winter, the opposite adjustment method is adopted to promote the volatilization of the solvent and reduce the occurrence of the paste phenomenon. For another example, aluminum foil and aluminized paper have different ink adsorption properties, and different squeegee adjustment methods should also be used. In addition, the squeegee pressure. The pressure of the embossing rubber roller, the tension of the printing material, and the adjustment of the solvent volatility should also adopt different adjustment methods according to the different seasons and the different raw materials.

    5. envirnmental factor

    The environmental sanitation is poor, and flying dust and other debris will fall into the ink, causing quality problems such as knife threads and blockage, resulting in unclear printed graphics. If the ambient temperature is too high and the solvent volatilizes too fast, it will also cause blockage, resulting in unclear printing graphics. If the environment humidity is too high, excessive water will penetrate into the ink, which will not only reduce the purity of the ink, but also cause fogging on the surface of the ink, making the printed graphics dull and unclear. Therefore, the environment of the printing workshop should be kept clear and clean, and the temperature and humidity of the environment should be kept as constant as possible.

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