【正文】 inting ink connection materials have the certain viscosity to play the disperser pigment role one kind of fluid medium in the printing ink. Its function as follows:(1)For printing ink by certain viscosity, stickiness, fluidity。(2) Decides the printing ink the dry type and the drying velocity。(3) Decides the printing ink glossiness, the resistance to wear, the reliability and so on.　　3. Printing ink assists the material the function:　　In the printing ink auxiliary material to aspect and so on printing ink tone, viscosity, thickness, dryness, fluidity makes certain adjustments.　　To assistance material request:(1)Pellet fine degree of fineness must be similar with the printing ink, cannot excessively be thick。(2)Cannot affect performance and so on printing ink coloring strength, adhesion。　　(3)Can very good dissolve with the printing ink gathers, does not have any chemical reaction?！　?4) Cannot play the corrosion to the printing plate and the chemical reaction role.Second, the printing ink discoloration, changes color the reason　　The printing product discoloration, changes color mainly is the printing ink performance question, but, also some are because printing labor art is the result of, as well as the printing ink meets the acid and alkali, the sulfide, is mellow as for example: The methyl alcohol, the ethyl alcohol (ethyl alcohol), the glycerol, the surfaceactive substance equalization study matter extremely is also easy to cause discoloration, changes color the question:　　1. Ink penetrations and conjunctiva process changing color: When the printing process, the print just prints good the black color is deep, however, after separates period of time the printing ink color could change palely, this was the printing ink not fast light reason by no means, mainly was in the printing ink drying in transit the seepage and the conjunctiva reason. The light shines through the connection material to the pigment pellet on, the colored light which reflects again to the sunlight choice absorption only then presents the color after the pigment. Light penetration ink membrane deeper, then reflects again the colored light is more saturated. Therefore said the ink level thick luster is thick, ink level transparent luster dazzling. Just printed good India, the ink level was thick. But after in the dry printing ink connection material will have the very big branch to seep into the paper textile fiber in, therefore the dry after ink level will want superficial somewhat, like this, the color also changed palely. When printing must the color control in pared to the original kind slightly thick degree, after then the printing ink is dry can achieve the original design color the request.　　2. Printing ink because the fast light does not cause discoloration: We when adjust the ink, should select the good printing ink as far as possible, any printing ink in the sunlight or under other illuminations, all can have the varying degree discoloration the phenomenon, in mixes the superficial color printing ink to be supposed to estimate the printing ink is diluted after the light resistance. Like pale lake blue color easiest to use cyanine blue, do not have to use the peacock blue, because the cyanine blue parison fast light, is not easy to change color. The pessimistic ink may in the chalk slightly the black ink and the cyanine ink。 The Paris green color may use the single color cyanine green, insufficiently yellow then may add the bright ink, bright also may the dot chalk, if adds the chrome yellow ink with the peacock blue, after a considerable period of time, is easy to exude yellow.　　If we accept for printing the product is pastes in outdoor advertisement picture, the picture poster, the lunar new year39。s painting and so on, because these products paste in the outdoors receive the sunlight the direct radiation, under the sunlight ultraviolet ray function, the wind blows, the rain drenches, the time long bright luster has been easy discoloration, discovers only then the black, the blue color these two kind of colors printing ink still exists. The superficial color, the yellow, the red printing ink all discoloration, after therefore said in order to reduce the solar ultraviolet ray illumination discoloration, when best four colors chromatography in the color foreword arrangement y, the m two colors first prints, C, the BK two colors put behind printing, like this, folds India in final C, the BK two colors has the lightfast heatresisting function, thus reduces India discoloration the phenomenon.　　3. Paper characteristics loose, rough changing color: If prints paper smoothness bad, paper surface roughness, loose offset paper, raised printing paper, news paper, and so on, paper absorptive quality big, printing ink pigment pellet tiny, together is absorbed gradually in the slow drying in transit along with the connection material by the paper, therefore the ink discoloration was pale. The paper increases to the printing ink absorption and the printing ink to the paper infiltration capacity, then can cause the connection material and the pigment separation, causes the ink membrane to change thinly, changes color, glossiness is bad, reduces the paper the absorption seepage time, must the corresponding enhancement drying velocity, red and white oil increase amount used in the printing ink.　　4. Between 5~6, the acidic moist fluid can affect to the printing ink changes color, in ideal moist fluid PH value =7, assumes the neutrality, at the same time the acidic paper, the moist fluid also has the resisting printing ink dry function.　　In the ordinary circumstances, the printing ink does not bear the alkalinity, prints golden Jin Mo, the bronzed electrification aluminum foil meets the alkalinity to be able to turn the ancient yellow, also gloomily does not have glossiness, center the blue ink meets the alkali to be able discoloration, the chrome yellow ink meets the alkali color to