The technology of corrugated box color printing is constantly improving with each passing day, but some problems in printing are still difficult to avoid, such as dot gain. If the control is not good, the printing quality of the carton will be seriously affected. The technology of corrugated box color printing is constantly improving with each passing day. From the early 7mm thick plate plus the low mesh number of ceramic anilox roll screen and high ink content, corrugated box color printing can only print low line number of dots, because the maximum dot gain is more than 30%, it is difficult to modify and compensate the prepress production. In the past, corrugated box color printing, 7mm thick plate processing thickness flatness is poor, Usually, it is set to exceed the normal required clearance between printing ink and printing press, so as to facilitate the transfer of ink; Relatively, the increase of outlets is also serious.

Later, in order to reduce the dot gain caused by overprinting of resin plate, the application technology of thin plate was pursued by everyone. It is also a way to improve the quality of corrugated box color printing by thin plate technology by using elastic pads to absorb excess pressure. However, this is only a performance when using the machine, but the advantages and disadvantages of the pads will directly harm the printing.

However, in order to meet the requirements of the era of high quality printing, the overall performance needs should be considered from the design of the printing surface. Relevant information must be collected from the beginning of the prepress solution, such as the conditions of the paper used, the type of corrugated, the precision of the printing equipment (overprint), the conditions of the ceramic anilox roller (mesh number and ink content), and the setting of the conditions for ink wash, Printing machine operation (after standard dot gain compensation calibration), find out the standard of dot gain, and finally carry out prepress operation. If the paper is unused, use the standard dot gain compensation calibration conditions to carry out prepress operation plate making, otherwise it cannot meet the expected calculation.

Therefore, it is necessary to do printing test on the printing machine. It is very important to give prepress personnel customized printing plates according to the machine's capabilities. Let's analyze various conditions for attention before printing:

1. Paper conditions

For coated whiteboard, ordinary whiteboard and ordinary corrugated kraft linerboard, the color of the paper after printing varies with the amount of ink transferred. A color rendering table should be made according to each type of paper to find out the gray balance of dot overlapping as the prepress production condition.

2. Corrugated type

The choice of corrugation will directly affect the use of the weight of the face paper. It is required that the cardboard should not be exposed (washboard phenomenon). The technology of A-corrugation or C-corrugation against the exposed cardboard needs to be overcome. Generally, if it cannot be overcome, the weight of the face paper will be increased accordingly. The combination of AE corrugation and CE corrugation with B-corrugation and E-corrugation can not allow the increase of the weight of the face paper to correspond to the printing effect; The complete corrugated shape and uneven corrugated height of the paperboard directly affect the setting of printing press. For the sake of partial thickness error of the paperboard, increasing printing press will make the overall dot gain conditions different, resulting in overall color difference. The high-quality printed paperboard line needs to be improved to cope with it, otherwise the cost of the paper will be killed by the whole batch.

3. Precision of printing equipment

The error of the printing machine is to consider direct overprint or hollow overprint before printing, because it is very important to make four color overprint hollow words before printing. It is necessary to use the design of patterns skillfully or use spot colors, and its use will be considered according to different patterns. If the printing quality is abnormal under the standard setting operation, immediately check whether the equipment is abnormal, Use the test plate to make a correction printing machine every six months.

4. Conditions of ceramic anilox roll

The production technology of using high mesh ceramic anilox roll has become more and more mature. In pursuit of the conditions of using high mesh ceramic anilox roll, the ink content is a need to consider. The ink transfer capacity after the ink content is directly related to the ink demand of the paper. It will be difficult to print the field layout on ordinary white board paper and corrugated kraft linerboard when the mesh of the ceramic anilox roll exceeds 550LPI, However, when the mesh of ceramic anilox roll exceeds 550LPI, the printing effect on coated white board paper will be more detailed than that below 350LPI, but the ink content of high mesh ceramic roll can be increased, so that the color of field printing surface will be brighter, the brightness dot transfer ink will be more abundant, and the loss of transfer printing of small measurement dot will be reduced. Therefore, the transfer of ink on ceramic anilox roll is very important, The maintenance should not be underestimated.

5. Conditions of ink and wash: requirements for ink and wash

The resins used on different papers are different, but the transparency of the four primary color inks in color lamination directly affects the final printing effect. The relative pre press color separation and dot conditions are closely related to ink wash. The requirements for acid base (pH) value and surface tension of ink wash on coated white board paper and ordinary white board paper or kraft paper are different, Coated white board paper has different needs from ordinary white board paper or kraft paper. In particular, the conditions of coated white board paper are very different from each paper mill. It is also a necessary process for offset printing to test ink on paper. Therefore, ink wash will make different suitability adjustments according to different mesh numbers, paper conditions, number of screen lines, environmental factors, etc. It is very important to do experimental plan recording conditions.

6. Conditions of printing plate

The 2.84mm thin plate of the printing plate is quite beneficial to the printing effect. The flatness and absorption of excessive printing pressure are better than 3.94mm. The printing plate must be flat in thickness. If you purchase the specifications of the printing machine, you must confirm the gap size between the ceramic wheel and the printing plate. The file making of prepress processing shall be compensated by the conditions displayed on the test plate. If this test is not performed, the printing will be distorted. To achieve the printing reality, the test plate and the confirmation effect after compensation must be performed to confirm whether the compensation is correct after correction.

7. Printing machine operation

After the above conditions are combined, the printing machine should be operated according to the standard, and the data standard should be set to achieve the "light" condition, so as to live up to the above hard prepress preparation

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