Test of the hottest plate and its printability 2

2022-10-15
  • Detail

Test of plate and its printability 2

v. change of ink

"is the transfer and printing performance of ink affected by its color, viscosity and pH value?" is there any difference between inks produced by different manufacturers? " Practical exploration has found answers to these two questions related to ink. In the test, three inks of different colors from three different manufacturers were used, and each ink was tested for three different pH values and three different viscosities

in this test, 3 × three × three × 3 = 81, that is, there are 81 parameters in total. In order to further reduce the workload, it was decided to test one color of ink separately. GCM 139 reduced the test parameters to 27 controllable parameters

the inks of manufacturer 1 and manufacturer 3 are stored in 5-gallon barrels. The pH value of ink 1 is 9.0 and the viscosity is 23 seconds (measured with 2 chann cup), and the pH value of ink 3 is 9.1 and the viscosity is 30 seconds. The ink produced by manufacturer 2 is stored in a 1 gallon bottle with a pH value of 8.6 and a viscosity of 46 seconds

in the test process, we start with adjusting the nine ink samples of each manufacturer, and the parameter settings are as follows: the pH value of the ink is set to 9.2, 8.8 and 8.4, and the viscosity is 24 seconds, 21 seconds and 18 seconds respectively (2 chann cup). Adjust the viscosity of the ink with water, and increase the pH value of each ink sample by adding pH stabilizer (amine compound) produced by various manufacturers. If you want to reduce the pH value of the ink, you can add a certain amount of water to the ink, or open the cover of the ink container to volatilize the amine in the ink, so as to reduce the pH value of the ink. In addition, the pH value of water is 7.0, which is neutral. Therefore, in addition to adjusting the viscosity of the ink, water can also reduce the pH value of the ink

next, the nine inks are combined with the previously used plates and substrates and tested on the IGT F1 flexographic printing suitability tester. The minimum pressure of the embossing roller is 30 Newton, and the minimum pressure of the embossing roller is 45 Newton. The printing speed of the corrugated roller is kept at 3 M/s, and the ink transfer capacity of the corrugated roller used is 9.0bcm/in2

then use these 405 data points to draw the assets of the energy storage system. 1. Generally, the corresponding ink parameters are in the hands of the energy storage manufacturer or system integrator (3 manufacturers × 9 adjustments × 5 color code printing samples × Each sample is measured 3 times)

VI. result report

the test results show that when changing inks from different manufacturers or when the viscosity and pH value of inks change, hue deviation occurs along the Yellow/green (a*) and red/blue (b*) axes

as predicted, the brightness changes the most. However, there are still great differences between different manufacturers. When the pH value of the ink is 9.2 and the viscosity is 24 seconds, only the ink of manufacturer 2 is closer to the error range of 1.5 △ E

gcm1 39mw standard average color difference (△ E) is ink 1 = 13.18, ink 2 = 7.9, ink 3 = 11.49

VII. Difference of printing plates

the test finally includes 13 printing plates and involves the plates included in the post-processing of corrugated board. When the plate is transported from the manufacturer, give a random code to the printing plate, install the printing plate on the tester, and measure the hardness of the remaining fragments

Table 1 printing plate hardness and type

printing plate B C D E F G H I JK l m

hardness 23.5 35 27.5 30 29 29 29 29 30.5 29 29.5 32 33 24.5

type liquid solid liquid liquid solid liquid solid liquid liquid liquid liquid liquid type

test

because the performance of the inks of manufacturer 1 and manufacturer 3 is very similar, the inks of manufacturer 1 and manufacturer 2 are selected for testing.The. In addition, only three different pH/viscosity grades were tested: ① pH 9.2, viscosity 24 seconds; ② PH value 8.8, viscosity 21 seconds; ③ PH 8.4, viscosity 18 seconds

for various ink parameter settings, the contact angle method is used to measure various printing plates. Each printing plate is installed on the IGT F1 flexographic printing suitability tester, and the used wrinkle roller, printing pressure, printing speed and substrate material are exactly the same as the previous. Three inks with different viscosities and pH values from manufacturer 1 and manufacturer 2 were tested on 13 printing plates, and a total of 390 printing samples were obtained

measure the color of each printed sample, but due to the aperture size of the spectrophotometer used, the visually perceived difference is very small. Therefore, it is necessary to measure the uniformity of the ink film

if the ink film is smooth and uniform, the inking coefficient is relatively low, and this coefficient will also be affected by the smoothness of the substrate material. However, since the same batch of substrate materials are used, the recorded value can reflect the performance of the printing plate

IX. performance of printing plate

some printing plates have the same ink transfer performance, which means that the inking performance of inks with different performance is similar after printing. Printing plates a, C, D, G, h and m have the same ink transfer performance and are not affected by the ink condition. Printing plate G has the lowest inking coefficient and the most consistent transfer performance

there is no relationship between the hardness and transfer performance (inking coefficient) of the plate. For example, the hardness of printing plate G is 29, which is just right, and its printing characteristics are also the best. Our conclusion is that the hardness of the plate cannot be used as a good indicator of its printability

when the data of 390 samples are subdivided according to a certain relationship, the following aspects are studied:

1. If the transfer performance of the printing plate is poor, the printing results will be different when using inks from different manufacturers or when the ink parameter settings (pH value and viscosity) are different

2. When only the inks with different pH values and viscosities from the two manufacturers are compared, the consistency of printed products printed with inks with pH value of 9.2 and viscosity of 24 is the best (except for plate I)

"In fact, 3. As the pH value and viscosity of the ink decrease, the predictability of the printed matter also decreases.

4. Some plates are more affected by the ink condition.

5. The comparison between different ink manufacturers is very simple. The smaller the inking coefficient is, the smoother the ink film is.

6. If the performance of the ink is changed, the situation is more complex. Under ideal circumstances, the pH value and viscosity of the ink are the same Good printing effect can be obtained by mutual cooperation

7. Measure the ink contact angle of manufacturer 1 and manufacturer 2 on each plate. It seems that there is a certain relationship between the hardness of the plate and the contact angle, with the exception of printing plates C and m

X. analysis of substrate materials

five substrate materials were planned to be tested previously, and later increased to 13. All printing machines, inks and plate parameters were tested. The printing pressure was 45 Newtons and the speed was 3 meters/second. The printing plate was selected as G, because the printing consistency of printing plate g was the highest in the previous test. The inks of various manufacturers are set as follows: pH value 8.8, viscosity 21 seconds. The number of samples obtained is 195 (13 substrate materials × 3 manufacturers × 5 printed drawings)

Table 2 substrate materials

x Ⅰ x Ⅱ x Ⅲ x Ⅳ x Ⅴ x Ⅵ x Ⅶ x Ⅷ x Ⅰ x XX XX Ⅰ XX Ⅱ XX Ⅲ

white background gray paperboard bleached paperboard white background gray paperboard bleached paperboard kraft paperboard white background gray paperboard bleached paperboard kraft paperboard kraft paperboard white background gray paperboard

analysis of substrate materials includes l*a*b*, smoothness of ink layer and contact angle. Use first ten angstroms (FTA) 125 and 200 software to measure the contact angle. FTA 125 is a dynamic video capture device, which can capture and measure the image printed on the substrate material at a fixed time (every 0.5 seconds), and the thickness of the ink film is maintained at 1~2 microns

Xi. Findings and conclusions

color difference △ e comparison can explain most of the differences between substrate materials and inks. Each substrate material is printed and compared with the appropriate samples in the Gcm1 sample book, such as the samples printed with kraft board and the kraft board samples in the atlas, etc

the biggest difference has little to do with the substrate material, but it has a lot to do with the ink. For example, when using the ink produced by manufacturer 2, 11 of the 13 substrate materials have the lowest color difference (△ E)

when printing with substrate material XX and manufacturer 1's ink, the color difference value (△ E) is the smallest. On the substrate XIX, the difference between the inks of manufacturer 1 and manufacturer 2 is less than 1 color difference unit. On the substrate material XXI, the color difference value (△ E) of the inks of manufacturer 3 is the smallest, but it is worth noting that the color difference value (△ E) of kraft paperboard is greater than 15

when comparing the inking coefficient and the contact angle of ink on the substrate material, some interesting trends deserve our attention. When printing with the ink of manufacturer 1, 12 of the 13 substrate materials have the largest contact angle, but there is almost no obvious difference in the first 6 substrate materials. In the rest of the substrate materials, the contact angle ranges from high to middle and then to low. When comparing the produced ink with the ink produced by manufacturer 2 and manufacturer 3, it is interesting that the contact angle of the substrate materials XVII, XVIII and XIX after printing is relatively small, while the contact angle of the substrate materials XVIII and XIX is relatively large, but the inking coefficient is quite the opposite, and the coefficient of manufacturer 1 on the substrate material XVIII is relatively small, The coefficients of manufacturer 2 and manufacturer 3 are relatively large; The coefficient of manufacturer 1 on substrate materials XVII and XIX is relatively large, while the coefficient of manufacturer 2 and manufacturer 3 is relatively small

XII. Conclusion

in order to accurately match the color of printed matter on the printing machine, we must match the ink on the actual substrate material in advance. It is very critical and important to measure the performance of ink and try to keep it constant. It should be remembered that the insiders ensure that the color difference is controlled within 2 units, which emphasizes that the pH value and viscosity of the ink should be continuously monitored during the printing process and kept constant

the setting and control of printing operation is also of great importance. If the pressure between the embossing roller and the printing plate or the pressure between the printing plate and the substrate material changes slightly, the color of the ink may change, resulting in a color difference of 1 unit

all kinds of plates can be printed, but not all plates can always maintain a good printing effect. When tested with various performance inks, three printing plates have good printability, they are plate a, G and m. If the printer intends to use only one plate, he can choose from the above three plates. On the other hand, the printer can also choose the oil block usually in a static state according to the specific situation of the graphic content of different printed live parts, and the range of selection may be larger

now we know that various variable factors (such as plate, ink, paper and printing pressure) should and can cooperate with each other in the reproduction process of a printed part. Therefore, testing in advance can avoid problems in the printing process

Copyright © 2011 JIN SHI