Before printing, the melamine base paper needs to maintain the average humidity of the paper to achieve high-quality printing effect. However, many factories have ignored this, and have a certain misunderstanding. It has mistakenly thought that the quality of the paper is not good! Actually that’s not right. The quality of the paper will certainly affect the quality of the printing, but some paper will wrinkle which causes many defective products during printing. Today, Shunhao Machines & Moulds is going to share with you the experience: How to keep the paper away from the wrinkles?

Normally, small tableware factories will purchase printed decal paper directly from the printing factory, and they only need to check the decal paper’s quality. The problem of whether the base paper will wrinkle before printing is a problem faced by printing factories. Some big tableware factories will be equipped with printers to print the paper the factories need, so they will also face the wrinkle problem.

The wrinkle problem will reduce the output and also the quality of the finished decal paper.

Now, let’s talk about how to fix this problem.

First of all, we must understand the moisture content of the base paper which is generally 7%. Big paper factories have very strict requirements in all aspects to achieve and ensure the quality of the base paper and even require vacuum packaging. The vacuum-packed base paper can keep the fresh color and 7% moisture content even after half a year. The base paper used by the Chinese government for printing RMB is very strict, and it is specially supplied by a well-known state-owned enterprise for a long time. Cooperating with such enterprises, there is no need to worry about quality. But after the paper leaving the factory, how can the tableware factories keep and use the decal paper in the right way? Let’s continue to find out.

The moisture in the air is 10%, and after unpacked, the base paper with 7% moisture content will begin to absorb the moisture in the air, especially the 4 corners of the paper with high absorption speed than the paper middle. That is to say, a package of 30 reams, the upper and lower layers of paper will absorb more moisture from the air than the paper in the middle. Therefore, there will be a problem with the uneven moisture content of the entire base paper. The four corners with more moisture will be obviously warped or bulged during printing. This is what we commonly call the "wrinkle problem". Then how to maintain decal paper moisture at 7% will be the best solution.

The following methods are valuable experiences summarized by most tableware factories in my country, which are worth sharing and learning.

1. If you pay attention to the quality of the base paper, you can purchase vacuum-packed base paper. The freshness of such base paper will be maintained for a certain period of time, which can meet the long-term needs. If you unpack the vacuum packaging of the base paper, take it out according to your need. The unused base paper should be wrapped in a film bag to prevent moisture from intruding. The decal paper for printing must be finished within 5 hours after taking out. If the cut base paper needs to be used after a few days, it is recommended to wrap it in film bag, which is also to prevent the intrusion of moisture, which may cause wrinkles.

2. The base paper can also be exposed in the air to allow it to fully absorb the moisture of the air to reach the average moisture content of the entire base paper. The approximate reference time is that the humidity can be balanced in 1.5-2 months in the summer; and longer time, even 3 months in the dry winter to reach a more balanced humidity. Of course, the base paper should be exposed in a clean, dry, and no sunlight place.

3. When the exposing time of base paper for equalizing humidity is too long, the factory will make some racks to separate the base paper in a pallet to fully absorb it and shorten the waiting time. For example, the whole pallet is 30 reams of base paper, which can be divided into 15 reams.

4. If the base paper has been wrinkled due to irregular placement, it can be baked with some fluorescent lamps to reduce the humidity on the four corners of the base paper. Certainly, this requires technology and experience.

In all, all these methods have only one purpose, that is, to keep the base paper at the same balanced humidity to avoid wrinkling problems when printing.

After reading this article, when you face the base paper wrinkling problem in printing, can it easily be attributed to the quality of the paper?