印刷光泽度w49

IGT Information leaflet W49IGT AIC2-5T2000 GLOSS (85 Shore A)Version : October 2003Introduction:When ink is printed on paper a part of the ink is partially absorbed by the paper. For the offset process this property is very important. If the ink is absorbed too slowly or too fast, it may result in a change of the dry ink properties. An absorption, which is too slow, may result in e.g. smearing because the ink does not dry fast enough. An absorption, which is too fast, may result in a reduction of e.g. gloss; in this case the absorption of the ratio of binding agent and pigments has been changed. This Information leaflet W49 describes a method to make a print to measure gloss. The printing form is covered with a coated rubber with a hardness of 85 Shore A. Information leaflet W71 describers the method with coated rubber of 65 Shore A.Often this method is used as a quality control test.Principle:The paper strip to be tested is printed with a standard gloss ink with the help of a printability tester. After drying the ink, the gloss is measured.To test inks, the method can be executed in the same way, but instead of a test ink the ink to be tested is used together with a standard paper.Method of operation:• It is recommended to execute the test in the standard atmosphere; to most standards it is 23.0 ± 1.0 °C (73.4 ± 1.8 °F) and 50 ± 2% rh.• For the operation of the AIC2-5T2000, the High Speed Inking Unit 4 and the ink pipette follow the instructions of the manuals, IGT information leaflet W100 and the displays accurately.• Handle the samples carefully.Preparation1.Condition the papers, the ink and equipment during > 6hours in the standard atmosphere.2.Cut the paper strips (preferable 55 x 340 mm, 3 strips persample) and mark them with top and/or bottom side, machine and/or cross direction and a code for the type of material.3.Adjust the printing force of the upper printing disc shaft to625 N and pay attention for the right backlash. See W100.4.Adjust the speed to constant (5), end speed 0.2 m/s.5.Check and if needed, move the slide in front of the sectorinto the constant speed mode (5).6.Check the functioning of the Global Standard Testerfollowing the instructions in the chapter “Execution”.7.Fill the ink pipette with the gloss ink.8.Adjust the High Speed Inking Unit with the settingsmentioned in note 2.9.Check the functioning of the High Speed Inking Unit. Execution1.Apply2.4 or 4.8 µm of ink to the inking unit and distributethe ink. (indication: 2.4 µm for art paper and 4.8 µm for rough paper). See note 3 or the manual of the inking unit. 2.Place the printing disc on the printing disc shaft of theinking unit and ink the disc during the preset time.3.Mount a test strip on the sector of the printability tester.4.Remove the disc from the inking unit and place it on the(top) shaft of the printability tester.5.Turn the sector into starting position.6.Press one of the side buttons to start the motor.7.Move the printing disc into printing position against the teststrip.8.Press the other side button as well to make a print.9.After the sector has stopped, release the side buttons.10.Move the printing disc out of printing position Materials / testing conditions12345678910IGT AIC2-5T2000IGT High Speed Inking Unit 4(with 4 segmented top roller forconventional inks)IGT ink pipettePrinting disc, with rubber 85 Shore A,coated, 50 mmGloss inkStrips of paper to be tested, preferable55 x 340 mm, 3 strips per sampleLint free ragsCleaning naphthaGloss meter710466.410.100(466.003.003)408.200 or 408.400402.333404.380.010Printing forcePrinting speedInk film thickness625 N0.2 m/s2.4 or 4.8 µmThe numbers 1 thru 6 are available at IGT Testing Systems.The numbers 5 thru 6 can be obtained as Gloss Set forAIC2-5T2000, article number 476.41211.Remove the test strip from the sector.12.Store the printed strip during >5 hours in a safe andpreferably to the standard atmosphere conditioned room. 13.Check the test result as pointed out in the chapter“Assessment”.14.Remove the printing disc from the tester and clean it withthe rags and naphtha.15.Clean the rollers of the inking unit or use the next segmentfor the following test.16.Repeat the points 1 thru 15 for the next test. It isrecommended to perform the test at least three times.17.After finishing the tests clean and store all parts as describedin the manuals.18.Make an accurate record of the conditions and the results ofthe test.Assessment1.Measure the gloss on the dried ink of the printed samplewith a gloss meter on every strip.2.Calculate the average and if desired, the standard deviation.Sometimes it can be useful to mention the highest and lowest values as well.Notes:1.The test results of the AIC2-5T2000, AIC2-5 and GlobalStandard Testers 2, 3 and 3H compare well with another on the condition that the tests have been carried out under the same testing conditions.2.It is advised to use the following settings for the High SpeedInking Unit 4:Water bath : 23.0º C (73.4º F)Mode : 2Starting time : 5 sDistribution time : 10 sDistribution speed : 1.2 m/sInking time printing disc : 5 s3.To reach an ink film thickness of 2.4 µm on the High SpeedInking Unit 4 with a 4-segmented top roller a quantity of0.104 cm³ has to be applied, for 4.8 µm the quantity is 0.208cm3. It is not advised to add some ink after a test.W49 for IGT AIC2-5T20004.To perform the test to test inks it is advised to use thestandard APCOII/II paper strips. The article number is404.009.025.5.The storage life of the ink in the original packing is 3 yearsmaximum; in an opened packing 1 year.This information leaflet has been compiled with the utmost care.However, may you find any inadequacies or if there are any comments,we kindly request you to send these to IGT Testing Systems, SalesDepartment.。