At present, portable paper bags are widely used in the packaging of clothing, food, leather shoes, gifts, tobacco, alcohol, medicine and other commodities. Some portable paper bags must go through a number of processing processes such as offset printing, printing gold, printing silver, hot stamping, film covering, indentation, folding, adhesion, holing, upper air eyes, and wearing ribbons. In order to make portable paper bags more exquisite, the printing production should pay attention to the following points.

1. Adjusting Printing Pressure

Handheld paper bags are often made of white board paper with a quantity of 250 to 400g. The paper is relatively thick, and the adjustment of printing pressure has put forward more stringent requirements. When adjusting, the center distance between the printing plate drum and the rubber drum remains unchanged. Just adjust the center distance between the press drum and the rubber drum. When the printing quantity is 250 to 450 g of whiteboard paper, the center distance of the drum can be widened by 0.20 to 0.40 mm. In addition, due to the poor surface smoothness of the whiteboard paper, its closeness is far better than that of the copperplate paper. Therefore, care must be taken to increase the printing pressure accordingly. To adjust the printing pressure, we can also use the method of increasing or decreasing the thickness of the rubber roller liner.

2. Adjust the offset paper part

When printing whiteboard paper, copperplate paper, card paper, and Kraft paper, due to the large amount of paper, the wind volume of the paper sucker and the blowing tip of the paper should be increased accordingly; The paper sucker should replace the larger diameter, thicker rubber rubber ring; The pressure spring of the drawing gauge can be replaced with a larger diameter model to achieve the purpose of not swinging the incoming paper and moving the paper smoothly.

When printing whiteboard paper, the gap of the dual controller of the offset press should be increased accordingly, and the distance between the press tongue and the cardboard of the side gauge and the front gauge should be increased. Prevent Zhangbaiban paper from blocking between the stamping drum and the rubber drum, causing "boring car" failure. The distance between the double control wheel and the input roller must not be less than 2 paper thicknesses, nor should it be greater than 3 paper thicknesses, otherwise the arched paper will stop when it passes; Or the double sheet of paper has passed through the surface of the controller, and the controller's power supply has not been touched and can not be used to control the double sheet. In addition, dusts or insulators on two electrocuted surfaces should be cleaned up in time to prevent the failure of the dual control system.

3. Prevent the back from rubbing dirty

Handbag printing often has a full version of the field, easy to cause back dirt. Therefore, the original barrel ink should be selected as far as possible, and some decongestants and anti-stick agents should be added appropriately. Do not add 6 # oil, and do not add dry oil when the weather is hot.

In addition, it can also be solved by spraying powder. However, it should be noted that the spray powder will affect the surface gloss of the printed matter and pollute the environment. It will wear and stick the parts of the offset press.

It should be noted that the correct arrangement of the printed color order. In order to avoid the back of the paper from colliding with each other when printing is not dry, the text and line plates should be printed first, and the real version should be printed again.

4. Arrange the print color sequence

In arranging the printing color sequence, in addition to considering the back of the dirt, we should also pay attention to the following points.

(1) First print the tone of the screen, then print the lines and the field. When there are four-color overprint mesh adjustment images on the handbag, as well as text, field patterns, and lines, in order to ensure the accuracy of the overprint and reduce the impact of paper retractions, the mesh tone should be printed first, the lines should be printed again, the field, and be able to identify the master. Hard before easy.

(2) Print dark color first and light color later. Due to the weak cover of light color ink, when placed in the rear overprint, slightly overprint is not easy to detect, overprint effect is better.

(3) If the water content of whiteboard paper, card paper, Kraft paper, etc. is uneven, wrinkled, and the surface strength is poor, causing powder and hair loss, you can first empty a water to solve the quality accident when monochrome printing.

1, the graphic color mode must be CMYK or grayscale.

2, if you need a large area of pure black background in the color map, it is recommended to use K :100, C :30, such black printing is brighter than a black color, and because the existence of the blue version can make up for the black printing false loopholes. Of course, this value is not fixed. I used to make a poster with K :100 and C :80. This is because the area is too large and the printing press is fast. It is difficult to make the color solid, so the value will increase accordingly. Also, if there is a warm color pattern on the entire figure and the edge is feathered, or there is a warm tone transparency, the value at this time is adjusted according to the actual main warm color tone, such as K :100, M :60, Y :70, This pattern transition is very comfortable and not as weird as it was at K :100. This phenomenon can be seen in the PHOTOSHOP test.

3, on the variegated pattern anti-white or anti-white thin lines. When choosing fonts(or the number of pounds of lines), pay attention not to use thin fonts such as imitation songs and fine circles, and try to use bold letters, official script, and other lines that are obvious in order to avoid the possibility that the set will not be correct and the text or lines will not be seen. clear situation.

4, do small hanging cards and other things that need to roll the box, punch holes, should be careful, try not to design the outer border. Because if there is a slight deviation in the plate position when rolling the box, there will be a situation where one side is large and the other side is small.

5, the design of newspaper manuscripts, offset paper printing should be noted, newsprint and offset paper are more ink eating, so, in addition to paying attention to the number of mesh when the film is released, but also pay attention to the corresponding reduction in color when making, such as making newspaper manuscripts. You need to see the grayscale of 30, so when you make it, you set the grayscale to about 24, so that printed on some gray newsprint, the actual effect is equivalent to the grayscale of 30. The offset paper is whiter than the news paper, and the adjustment color can be lower than the normal copper printing, and it is higher than the newspaper manuscript, depending on experience and feelings.