Analysis: printing sequence of flexographic printing

At present, color printing is usually performed by using yellow, magenta, cyan, and black four-color plates and superimposing them in a certain order. Theoretically speaking, four-color printing can have twenty-four different printing color sequences. The use of yellow, magenta, cyan, and black four-color plates regardless of the type of printing color sequence used should achieve satisfactory results. However, in fact, the printing color sequence is different, and the color rendering effect of printed materials is also different. Reasonable printing color sequence will make the picture color closer to the original, and even strengthen the atmosphere of a certain color, adjust the picture level, make the outline clear, distinct or soft. In addition, it can also protect the paper surface, increase the gloss of the product, and facilitate overprinting. Therefore, in the case of color printing, especially packaging printing, more than four colors or spot colors, and a full version, attention should be paid to the arrangement of the printing color sequence.

In flexo printing, the various plates are often field versions, and the aqueous ink used is generally not very transparent. Therefore, when arranging the overprinting sequence of various printing plates, it is necessary to consider whether or not the color after stacking can meet the requirements of the original and achieve a good overprinting effect. It directly relates to the quality of printed products. The printing color sequence is mainly based on the order selected by the original design and the plate making. However, depending on product features and process requirements, there are often changes.

The color sequence in general flexographic printing is determined by the following conditions.

1. The first printing of strong ink hiding power. General first light color ink, dark ink after printing;

2. When the number of overprinted colors is large and dark rules are not used for overprinting rules, dark outlines should be printed first;

3. It is necessary to cover the edge of the image outline with the darkest color, and when the burr of the outline is eliminated, the dark color must be overprinted. But sometimes this dark color is a color code. At this time, a part of the dark color can be printed first as the specifications of the various colors, and the dark outline is finally overprinted;

4. The main colors of the picture patterns are generally arranged in the final overprint;

5. For the same color of existing outlets and field full editions, to satisfy the requirements that the outlets do not paste the version and the full edition on the ground does not produce flowers, the screen edition and the full edition on the ground shall be separately printed. In this way, the printing pressure can be adjusted individually and different inks can be used to ensure the printing quality.

For tri-color printing, the general color sequence is: cyan-magenta-yellow. The density of the field is controlled at 1.6 in green, 1.4 in magenta, and 1.2 in yellow.

Let's talk about a very important application field of flexo printing: printing color sequence of plastic flexible packaging color printing:

Plastic flexible packaging printing is generally based on white ink laying background to set off other colors. Its advantages: First, the plastic white ink and the polyolefin film (PE, PP) have the best affinity and the best adhesion fastness;

Second, the white is total reflection, making the print more vivid colors; Third, thickening the printing ink layer, so that the print level is more abundant, more three-dimensional.

Flexographic printing plastic flexible packaging "in India" and "table printing." "Reprint" refers to a special printing method that uses a printing plate that is printed on a transparent film (inverted text) to print a positive image on the front side of the film.

The "seal" and "in India" are the opposite of the color sequence. For example, a table print is generally printed with a background color first, and a middle print is the last background color. The "print" color printing sequence is generally white-yellow-magenta-cyan-black. "In India" color printing color sequence is generally: black - blue - magenta - yellow - white.

"Li-India" prints are compared with "Table-printed" prints, and they are bright, beautiful, colorful, non-fading, moisture-proof, wear-resistant, durable, long-term preservation, non-adhesion, and not broken. Because the ink is printed on the inside of the film (via the composite ink layer sandwiched between the two films), it does not contaminate the packaged articles and meets the requirements of the commodity hygiene law.

Flexographic printing presses are multi-color printing presses. Overprinting of inks is performed in a wet-stacked manner. At least 6 colors, generally 10 colors, up to 12 colors, can be used for UV and IR coating. Printed products are mostly decorative prints, with text, images, network cables, and on-site, and some also require gold, silver, and glazing. Therefore, the color sequence of flexographic printing is very flexible. When deciding on the printing color sequence, it is not possible to consider one factor in isolation, and it is necessary to analyze the specific requirements of the printed matter in order to obtain the best printing color sequence. For example, you can print the cable version first, then print it, print it again, and finally polish it. Some prints have dark ink and are limited by the amount of ink transferred by the anilox roller. When the thickness of the ink layer is not reached, another print unit can be used to reprint the ink. For the four-color screen color sequence can not be freely exchanged. For spot color printing, the order of lightness and darkness is generally adopted. Light-colored ink is printed first, and dark ink can be brightened after the superimposition. For a spot color printed by a stacked-color method, the color sequence of the main color and the sub-color is a secondary color first printing, and the main color is printed afterwards.