How to print whiteboard best 2

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How to print white board

cigarette box outer packaging, wine box, food box and other box packaging and decoration printing products are often printed with 250-400g/m2 white board and card paper. The maximum paper thickness that can be printed by offset press is 0.9mm, but generally, the thickness of the paper to be printed is often only 0.04-0.3mm. The difference between whiteboard and coated paper, offset paper and relief paper lies in the paper thickness. In the process of offset printing of whiteboard, the paper feeding part, embossing part, color sequence arrangement of printing, ink balance and many other parts of the offset press should be adjusted accordingly. 1、 Cylinder lining and pressure adjustment

when printing white board, the center distance between the printing plate cylinder and the rubber cylinder does not change. Just adjust the center of the stamping cylinder and the rubber cylinder. When printing 250-450g/m2 white board, the center distance of the cylinder can be increased by 0.2 It is reported that 0-0.4mm, due to the poor smoothness and roughness of the surface of whiteboard, the tightness of the paper is far better than that of coated paper. When printing whiteboard, we should also pay attention to the pressure of printing

for printing 400g/m2 white board, the gap between the printing plate cylinder and the rubber cylinder is 3.95mm, the gap between the rubber cylinder and the embossing cylinder is 3.40mm, the total thickness of the printing plate cylinder is 0.65-0.75mm, the total pad of the rubber cylinder is 3.15, and its particle size is between 1~300 m-3.35mm (measured with a micrometer). If the paper becomes thinner from thick, the reduced thickness, that is, the thickness of the lining removed from the printing plate pad, should be added to the rubber cylinder, If the paper turns from thin to thick when printing, subtract a certain thickness from the rubber cylinder liner, and add the corresponding thickness to the liner of the plate cylinder

II. Adjustment of the paper feeding part of offset printing

1. When printing whiteboard, the air volume of the paper suction nozzle and the paper blowing nozzle of the paper feeding part should be increased correspondingly

2. The paper separating suction nozzle and the paper feeding suction nozzle should be replaced with rubber rings with larger diameter and thickness, and the tension gauge compression spring can be replaced with steel wires with a diameter of 1.5mm; By removing the connecting pin between the feed roller cam and its shaft, or the roller on the swing rod, the purpose of non swing of the feed roller and stable paper feeding can be achieved

3. When printing white board, the double sheet control or gap of the offset press should be increased accordingly; The distance between the paper pressing tongue of the side gauge and the front gauge and the distance between the safety bar and the paperboard should be increased

4. The distance between the paper feeding tooth pad and the surface of the embossing cylinder and between the paper feeding tooth pad and the paper feeding board should be increased, and the distance should be kept about equal to the paper thickness plus 0.3mm

III. color sequence arrangement during printing

1. Products printed on white board include Hong Kong version field, as well as words, lines and patterns. For example, for the printing products of express mail envelopes, wine boxes, cigarette boxes (bar boxes) in the postal department, the best color sequence for printing is to first print words, lines, and patterns, and then put the full page on the ground and finally print on the machine, so as to avoid the phenomenon of touching, rubbing, and sticking on the back caused by the mutual collision of papers when the whiteboard is thick and the imprint is not dry

2. Print the dark color on the front and the light color on the back. Because the dark color ink has strong hiding power and strong adhesion, print it first on the front, which is convenient for accurate overprint; Light colored inks have weak hiding power, so it is difficult to observe that the overprint effect is much better when the printing volume is slightly out of order at the back

3. Often in a printed product, there are half tone four-color points, and continuous adjustment of patterns, words, lines. Main performance characteristics of gas spring performance testing machine:. The four-color electric separation point should be printed first, which is conducive to accurate overprint and reduces the influence of paper expansion. Then print continuously adjusted patterns, words and lines. In the arrangement of printing color sequence, we should recognize the primary and secondary, and it is more appropriate to be difficult first and then easy

4. If the weather is hot and the water content of the paper is uneven, the wrinkling is uneven, and the surface strength of the paper is poor when printing monochrome on whiteboard, it is also possible to empty print a layer of water first to solve the problem

IV. how to prevent the white board from sticking

1. Try to use the original barrel of ink when printing the full version on the ground, without adding 6 # inking oil, and appropriately add some de sticking agent and anti sticking agent; Do not add dry oil when the weather is hot. It is often easy to get dirty on the back of the full plate on the spot, which is often solved by spraying powder. Although the printing anti sticking powder contains pure vegetable materials, and its dispersibility and fluidity are good, the use of powder spraying agent will directly affect the surface gloss of printing products, make the ink not bright, pollute the environment, and have an impact on the accuracy of offset printing machines

2. The surface of the white board is rough, the quality is loose, the ink absorption is large, and the flatness is poor. Therefore, when printing the full plate on the ground, the bottom color should be printed first, and then the dark color. The bottom color should be darker and thinner, and the ink color should not be too large. If the flatness of the white board is good, then when printing the full plate on the ground, you should first print the dark color, and the ink volume should be enough, subject to the fact that the back side is not sticky and dirty, and then print the background color thinly, so that the smoothness of the printed product will be better. At the same time, pay attention to the balance of water and ink, and control the water content of the printing plate surface

in addition, when the offset press prints white paper, because the paper is thick, multiple white papers are blocked into the impression and rubber drum, which is easy to cause "stuffy car", so before starting printing, we must carefully adjust the devices of double sheet control, skew control, pre punching control and other electrical appliances properly. During double sheet control, the distance between the double sheet control wheel and the paper feed roller should not be less than two sheets of paper thickness, but not more than three sheets of paper thickness, Otherwise, the paper of the curved arch will stop when it passes through the controller; Or the double sheet has passed through the controller, and the two contacts of the controller power supply have not yet contacted, so the purpose of controlling the double sheet cannot be achieved. Timely clean the dust, dirt or insulation on the surface of the double sheet control wheel and the paper feed roller, or on the surface of the two contacts at the power control, so as to prevent the double sheet control system from malfunctioning, causing "traffic jam", and the failure of the rubber roller and the embossing roller

reprinted from: Printed today

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