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How to solve the problem of irregular drawing in printing blank?
Jan 08, 2019

The random drawing of the printing blanks shows an irregular ink track that is sometimes absent and sometimes short, usually thick. The reasons and solutions are as follows.

 

1. There are foreign bodies stuck on the edge of the scraping knife or under the knife

 

In the process of printing, the scraping knife can be moved back and forth, up and down, and the stuck foreign matter can be dropped or removed directly on the scraping knife blade with a bamboo stick (it must be completed by skilled operators to avoid unnecessary losses caused by improper operation). When necessary, the machine should be stopped to thoroughly clean the scraping knife.

 

2, ink cycle is not enough

 

Part of the ink in ink slot corner position, due to can not get good circulation resin precipitation, form the crystallization of different size and agglomeration, or too dry skin surface ink during the spring and autumn (summer skin prone to ink, ink because of the influence of the temperature crystallization and agglomeration situation more), as the cycle of ink, some ink crystallization or ink skin was turning version of drum to the blade, scraping blade will be broken to form a random drawing. So must be improved from the ink circulation and filtration.

 

(1) cycle improvement. Method one, the ink tank left and right, ensure that the ink can be slightly higher end injection, from the lower end of the outflow, forming a good cycle; Method two, the ink tank flat, but the ink must be injected from both ends at the same time, from the middle of the reflux, this can also form a good cycle, not from the unilateral injection of ink.

 

(2) improvement of filtration. Ink must be used before the first filter, even if the new ink also to filter, generally use 140 mesh/inch filter. Ink in the ink tank loop filter work is more important, it is a good way to filter out the ink in the use of the resin in the process of crystallization and the foreign material, choose the mesh should be more thin, method is below the set of a silk stockings, ink fountain on the way out to form a filter set, in the filter after a period of time, if the filter is blocked, poor flow of ink, can be set on the top of the bucket skewer inserted a few small holes, increase the guide effect of ink, set down to the bottom of the bucket can also play the role of good deposited impurities, as shown in figure 3. Some large printing plants in Shanghai and guangdong are using this method is a good control of the ink intermittent drawing problem.

 

3, ink fatigue

 

This situation occurs in the printing plate inking area is relatively small. In the printing process, the resin in the ink is constantly consumed, if the solvent is added without adding new ink, resin can not be supplemented, so that the proportion of each component of the ink changes, resulting in ink fatigue and affect the normal use. Appropriate addition of new ink can solve the problem.