Talking about the Failure Caused by Ink Printing Process and Its Treatment Method (I)

The prints left on the prints are formed by ink. The ink is the colorant used for printing and is the main raw material for printing. The ink is crucial for the quality of the print. When the ink properties are not suitable for printing, it will cause a series of processes. Failures severely affect the progress of production and the quality of products. The printing operator must change some of the properties of the ink to suit the needs of the printing, but some malfunctions are caused not only by the ink, but also related to other factors, so the printing operator must carefully analyze the correct treatment. This article discusses the failures caused by the ink printing process and the treatment methods, hoping to be helpful.

First, the imprinting is slow

Phenomenon and Cause: After the imprint is transferred from the printing plate to the paper through the blanket, it is generally required to be dried in about 10 hours to facilitate the post-color printing or finished product inspection. Once the imprint has dried, this will not only make the next color impossible. Overprinting, but also easy to make the back of the print dirty. The dryness of the blot has three factors: oxidized conjunctiva, paper absorption, and moisture evaporation. We must master the operation and prevent it in advance. The common causes of slow-drying are the following:

(1) Paper pH is 6 or less.

(2) The PH value of the bucket is 3 or less.

(3) The layout of the water is large and the ink is too large to cause serious ink emulsification.

(4) The workshop temperature is low. Relative humidity is higher than 75%.

(5) Absorption of paper is poor.

(6) There are too many auxiliary materials such as ink varnish and detackifier in the ink.

(7) The amount of dry oil is too small.

Approach:

(1) In order to prevent the print from appearing slow-drying, the height of the printed matter should be reduced, fluffing loose paper piles, and the air penetration of the semi-finished product can allow air to infiltrate the stacked paper, shortening the time for oxidation and conjunctiva.

(2) If the printing is urgently needed, use the original printing plate for dry oil overprinting. The formula is 70% for VERI oil and 30% for dry oil.

(3) In order to prevent unfavorable drying, add appropriate amounts of dry oil, dry oil consumption: winter more than summer, after the color than the previous one more place, dilute the ink more than did not dilute the ink more. $Page break $

Second, not color

Phenomenon and reason: Ink is added with too much dry oil or semi-finished products are stacked for too long, resulting in too fast drying to cause vitrification on the surface of the blot, the blot surface is too smooth, loses adsorption capacity, and the latter color cannot be printed. This failure is common in full version of the field, especially yellow (ink) or line prints.

Approach:

(1) Prevention is the main method. Add appropriate amount of Veoli oil, Kangbang, Magnesium carbonate powder and other auxiliary materials to the yellow ink that easily produces vitrification, to make the surface conjunctiva rough or extend the drying time.

(2) If the vitrification phenomenon has already occurred and the latter color is not printed, if the number of products is small, a soft cloth and magnesium carbonate powder can be wiped gently on each surface of the ink film, and then a color is set. Larger quantities can be printed while cauterizing alkali water. $Page break $

Third, the back of the dirty

Phenomenon and reason: Back sticky refers to the semi-finished product or finished product entering the delivery pile, the back of the ink is dirty on the next sheet. The cause of back sticking is.

(1) The surface of the paper is too smooth.

(2) The ink is too thin.

(3) Layout surface water and ink.

(4) The color quality of the ink is too light.

(5) The printing pressure is too light.

Approach:

(1) In the printing process, there should be no water, big ink, or large ink. Control the layout water, darken the ink, and reduce the ink fountain ink volume. If the water content is reduced to produce a greasy or mushy plate, clean the water roller or replace the new water roller, or properly strengthen the acidity of the water bucket solution and put some gum arabic.

(2) The ink is adjusted too thin and easy to stick on the back of the dirty print. New ink or some new ink should be transferred to increase the viscosity of the ink.

(3) The use of pale complex ink is commonly used in the deployment of light red, light blue, light tea, light gray ink, and should be deep-tuned to improve its color quality, to avoid printers from feeling too light, in order to achieve the hue of the sample. The requirement to artificially increase the amount of ink to be delivered causes the ink layer to be printed too thick to produce a dirty backside of the printed product.

(4) During the printing process, the rubber roller must ensure sufficient printing pressure when transferring the paper to the paper, so that the ink is completely transferred on the surface of the blanket, and the back of the printed material is prevented from getting dirty. $Page break $

IV. Powdering

Phenomenon and Cause: Ink pulverization refers to the fact that after the semi-finished product or the finished product is dried, the ink layer cannot be well combined with the paper surface, and the surface of the pigment particles will fall off as a result of slight friction. This pulverization phenomenon is related to the properties of paper and ink, in addition to the high acidity of the water bucket medicine and the presence of too much surface active material. Common ink powdering has the following reasons:

(1) The adhesive force of the ink is too small and the surface of the paper is relatively smooth, so that the ink layer and the paper surface cannot be well combined, resulting in the ink layer being wiped off from the paper surface.

(2) The ink is too thin, the linking material is easily absorbed by the paper, a large amount of the linking material penetrates into the paper, which promotes the separation of the linking material and the pigment in the ink, causing the pigment particles to float on the paper, and the pigment loses the linking material. Adhesion, the degree of its connection is reduced, and it does not adhere well to the paper surface, resulting in falling off.

(3) The used ink is emulsified seriously, which not only reduces the viscosity, drying speed, and increases the penetration. More importantly, the emulsified ink conjunctiva does not combine well with the paper surface, the adhesion is poor, and the film is firm. Very poor, slight rubbing will cause the film to break and fall off.

(4) Coated paper is made by coating the base paper. The paint and base paper have strong absorption, and the paper is thicker, can absorb a large amount of linking material, and the coating surface is smooth and the pores are very fine. It is possible to inhale the pigment together and act as a filter layer, causing the pigment particles to float on the paper and fall out of the package due to lack of binder.

Approach:

(1) No printing paper with strong absorptivity (absorbency less than 30 seconds), otherwise it must be printed with resin ink with strong adhesion.

(2) Add appropriate amount of No. 0 varnish or adhesive to enhance the adhesion of the ink to the paper surface.

(3) Control the emulsification of the ink, and the water consumption of the layout should be small. The PH value of the water bucket solution is often measured and adjusted to the required value. The dry oil is added with the use, and the ink emulsification is reduced so that the drying time can be grasped.

(4) Fine products that have been pulverized can be treated by glazing or filming.