Analysis of the most popular web concave horizonta

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Analysis of Web concave horizontal registration

people who have been in contact with web concave printing know that the horizontal shrinkage of the paper will be caused by the contact of ink (especially water-based ink) with the paper, which will cause inaccurate horizontal overprinting. To solve the problem of horizontal overprinting has become the key and difficult problem of cylinder paper gravure printing for the mechanical property test and process capability analysis of various springs. In combination with the actual production experience of paper concave, the following is a simple analysis on the problem of overprint accuracy which aims to promote the overall upgrading of China's new material industry

1. The transverse shrinkage of the paper is related to the humidity of the paper itself. The paper roll needs to be equipped with the following testing instruments: quantitative sampling knife, electronic balance, paper thickness gauge, ring pressure gauge (paperboard pressure gauge), tension machine, moisture tester, bursting tester, folding tester, surface absorption weight tester, smoothness tester, whiteness tester, stiffness tester, gloss tester, etc. Different water content before printing will lead to different shrinkage rates, resulting in inconsistent horizontal registration. The solution is to add a preheating oven to the printing machine before printing, and try to control the moisture content of the paper before printing

At the same time, it also has a respiratory effect

2. According to practical experience, the amount of contraction is reserved horizontally during plate making. Make the plate shrinkage consistent with the actual paper shrinkage

3. The transverse shrinkage of web paper from different manufacturers is often inconsistent. It is better to use the same manufacturer for the same set of plates

4. Different water content of ink will produce different shrinkage of paper. Therefore, the water content of the ink should be controlled so that the water content of the ink before and after the ink is consistent and the viscosity is consistent

5. Control the temperature of the drying oven. Different drying humidity of the drying oven will lead to different water evaporation rates, resulting in different horizontal shrinkage rates. In actual operation, the drying oven shall maintain the same drying temperature for each printing. The oven temperature can also be appropriately increased or decreased according to the actual horizontal overprint error

reprinted from: China Packaging News

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