Detect ink layer abrasion resistance to improve product print quality

Editor's note: Nowadays, the requirements for quality of printed matter are higher and higher, and the requirements for the abrasion resistance of the ink layer are also different. In view of the customer's satisfaction with the printing quality, many packaging and printing plants ensure the stability of the printing color. The wear resistance of the ink layer is generally adopted by some inspection instruments such as densitometers, friction testers, etc. to inspect the printing quality. In order to promote more rigorous and quantitative printing quality control, special test instruments should be used as far as possible. The following is a brief introduction to the detection technology and testing methods of ink layer wear resistance.

The control of the abrasion resistance of the ink layer is particularly important in the printing of cartons and cigarette packs. If the control is improper, the product will cause the ink layer to fall off due to storage, transportation, migration, etc., which will seriously affect the appearance of the printed products and ultimately affect the interests of users. It is understood that there are several methods for controlling the abrasion resistance of ink layers in printing production:

1) Adopt the friction tester and spectrodensitometer and strictly implement the national standard. Most of these manufacturers are powerful manufacturers that can control the wear resistance of the ink layer.

2) Use a friction tester to test the wear resistance based on the change of the specimen before and after the friction, but it is impossible to quantify the wear resistance. At present, such manufacturers account for the majority, and most of their customers can accept it.

3) Without testing equipment, experience wear resistance in production, that is, through visual inspection. Hand touch. It can also control the wear resistance within the specified range, but it is highly dependent on people. Such manufacturers also account for a certain number.


First, testing equipment
The abrasion resistance test of the ink layer requires the use of a friction tester and a color densitometer.

1. The requirements of the friction tester
1 friction body: 2 pieces of rubber with hardness of HS5O-53, area of ​​25mm x 50mm, thickness of 8mm, and distance of about 45mm.
2 Friction speed: 43±2 times per minute, stroke 60mm. 3 Load: 20±0.2N.

2. Color density meter
Densitometer test error should be ≤ ± 0.02D, can use ×-rite series 500 spectrometer densitometer, which can measure CMYK four-color density, accuracy up to 0.001D.

Second, the test conditions

1 The friction paper is an 80g/m2 clean offset paper with a width of 50mm. According to experience, office A4 printing paper can also meet this requirement.
2 The standard of friction frequency is 40 times back and forth. Jinan Languang's friction testing machine is set 0-999 times. Different times can be set according to user requirements.

Third, the test procedure
1 The sample cut to a certain size is fixed on the friction table. The area of ​​the ink layer to be measured is larger than the area of ​​the friction body. Generally, the area is 300 mm×55 mm, and try to take a sample with a relatively uniform color to facilitate measurement.

2 Measure the color density of the ink layer to be tested on the sample, and measure the average value at 3 points. The maximum density of four-color medium density should be taken as the measured value.

3 Fix the friction paper on the friction body, and gently place the friction body on the sample to be rubbed.

4 Set the number of frictions (40 times), open the friction tester reciprocating friction times, and stop to remove the sample.

5 Measure color density on the most heavily rubbed ink layer. Measure 3 points and average.

IV. Test results and standards
The print ink wear ten life is calculated as follows:

Ink resistance=D/D0×100%

In the formula, D0: average density before rubbing: D: average density after rubbing.

The national standard (GB7706-87) stipulates that the wear resistance of decorating printed matter should be ≥70%. This standard is applicable to printed decorative prints that are printed using a flexographic printing process. It does not apply to plastic film prints. This indicator can effectively guide the printing plant to control the ink layer. When the wear resistance is low, the production process can be adjusted as soon as possible to reduce the number of non-conforming products; at the same time, the quality of the product can be graded based on this parameter. .

Reprinted from: Ke Yin Network