Technical design and plate making of manuscripts w

Technical design and plate making of composite flexible packaging manuscript design of composite flexible packaging is the first step in the design and manufacture of composite flexible packaging. Unreasonable manuscript design will increase the printing difficulty, reduce the printing yield, and may also cause difficulties in cutting, bag making and other processes, and even cause the scrap of the whole batch of products

the manuscript design of composite flexible packaging generally has two types, one is artistic design, the other is technical design. Artistic design belongs to art. This paper mainly discusses technical design and plate making

I. design of electric eye cursor

in the process of automatic packaging of bags or composite coiled materials, positioning heat sealing and positioning cutting are often carried out, so it is necessary to set electric eye cursor in the manuscript for positioning. Generally, the electric eye cursor can be placed at the bottom of the bag during design, which is more beautiful. The electric eye cursor can be on one side or both sides of the coil. However, it is recommended to have it on both sides, so that some coil electric eye cursors are on the left and some are on the right, which requires continuous adjustment of the position of the photoelectric eye. The size of the cursor also has certain requirements, and different packaging opportunities have certain differences. Generally, the width of the cursor is more than 2mm, less than 10mm, and the length is more than 5mm. The width of the cursor (less than 2mm) may affect the normal tracking of the equipment due to the weak signal. If the cursor is too wide (more than 10mm), one side of 0.36 ~ 0.40 is not beautiful. On the other hand, it will reduce the tracking and positioning accuracy. The length of the cursor should generally be greater than 5mm. Due to the jitter and deviation of the film roll during the packaging process, the cursor is too short, which may make the cursor deviate from the position of the photoelectric eye, resulting in inability to track

the cursor is generally dark, which has a large contrast with the background color, and it is best to use black. Generally, red and yellow cannot be used. Now the reason of Document No. 65 will not be fulfilled and the new standard will be issued soon. It will bring new opportunities and new trends to the research and development of the new generation of organic thermal insulation materials in China. An expert review at the technical level will be made as the cursor. It is also not allowed to use the color code with the same color as the photoelectric eye as the cursor color, for example, the luminescence of the photoelectric eye is green, The light green color cannot be used as the cursor color of the electric eye, because the green photoelectric eye cannot recognize the green color. If the background color is a darker color (such as black, dark blue, dark purple, etc.), this time scale should be designed as a light color cursor with hollowed out white

for bag making machines, there is generally a microcomputer controlled electric eye tracking system with fixed length. It can select the photoeye signal within a certain position range to be valid (generally, the signal within a fixed length of ± 3mm is valid), and the text and pattern within this range can be "ignored", so the cursor can not be designed. However, it should be noted that in order to use too small and too short text patterns as tracking points, nor arc-shaped or slash shaped patterns as tracking points, if there is no suitable tracking point, the cursor must be designed

the electric eye system of general automatic packaging machine is a simple identification system. It cannot have the function of intelligent fixed length like the bag making machine, so the film rolling within the range of the longitudinal electric eye cursor is not allowed to have any interfering words and patterns, otherwise the interfering words and patterns will be mistaken for the electric eye cursor during the packaging process, causing recognition errors. Of course, there are some electric eyes with high sensitivity, whose black-and-white balance can be precisely adjusted, and some light colored interference signals can be removed by adjustment, However, the interference signal to the pattern whose color is similar to or darker than the cursor cannot be removed

the spacing between cursors is used to determine the length, but the error between the actual spacing and the design value should not be too large. Generally, only ± 0.5mm error is allowed. For many automatic packaging equipment, the tracking effect of negative deviation is better than that of positive deviation, so it is recommended to design negative deviation. For some automatic packaging machines, only when the spacing between cursors is negative deviation can they work normally. There are very few automatic packaging machines, which not only require negative deviation in the spacing between cursors, but also have high accuracy requirements. For example, the automatic packaging machine made by Siebler company in Germany, which requires hundreds of composite polyurethane adhesive manufacturers in China, and requires that the error between each cursor not exceed -0.02, -0.08

aluminized or pure aluminum has strong specular reflection, which will affect the identification of the electric eye. It is recommended to print a white background on the composite film cursor. For the transparent composite film, because it will be affected by the color of the objects in contact with it, it is also recommended that the cursor be printed with a white background, so as to reduce the interference of other background colors

for some multi row packaging machines, in principle, only one set of electric eyes is required, which are generally placed in the middle of the composite film coil. After packaging, it can be retained in the packaged finished product, or it can be cut off as the remaining edge. If it is retained in the finished products, there will be such a problem: some products in the same batch with light marks have no cursor. In order to avoid this difference, the packaging materials in multiple rows of packaging machines can be printed with a cursor on each column (although the packaging machine only needs a column of cursor)

second, the design of printing technology

when designing manuscripts, many art experts only design from the perspective of art or lithography technology, and do not fully consider some particularity of gravure printing technology. From the perspective of gravure printing technology, the manuscript design of composite flexible packaging should pay attention to the following points:

1. The overprint accuracy of gravure printing can only reach 0.2mm, so the text and graphics (especially the text) with strokes less than 0.4mm cannot be printed by multi-color superposition, and can only be printed with a single ink, otherwise it is easy to cause ghosting

2. Small words and patterns should be hollowed out in single color, rather than multi-color overlay hollowed out printing, let alone directly hollowed out printing with the bottom color of the photo. For small words and patterns, it is not suitable to use text patterns hollowed out overprint text patterns

3. pay attention to the size of words and the thickness of strokes. Too small words and too fine strokes may not be printed, and the printing failure of broken or even missing pens often occurs. For text that is too small, if there are too many and dense strokes, and the lines are thick or the printing plate is too deep, check whether the friction moving part should be filled with lubricating oil, which is easy to appear the phenomenon of "pasting words"

4. The transfer performance of gravure printing is not as good as that of lithography. There is a problem of blocking plates. Generally, points below 10% should be avoided. In particular, the ground color of a large area should avoid being too shallow, otherwise its point reproduction is not good, which is easy to cause uneven color and easy to change color. Even if it can be printed at the beginning, because it is too shallow, it is easy to affect the hue due to the wear of the plate roller in the printing process, and the print resistance of the printing plate is low. Spot color printing is recommended for large-area light colors

5. Although in principle, all colors can be produced by the superposition of three primary colors, in fact, there are many colors with high purity and bright colors, as well as some special colors such as fluorescent color, transparent color, gold, silver, etc., which must be printed with spot color. At this time, a spot color plate roller must also be made to print. (to be continued)