At the stage of rapid development of China's economy,the contradiction between economic growth and cost expansion has become increasingly fierce.However,this contradiction is not irreconcilable.In the highly polluting printing industry,green printing is popular.In the process of continuous improvement of many printing equipment,how to make gravure printing machine have great advantages in cost saving and pollution reduction?
Gravure printing is generally used for high-speed printing of high-quality multicolor long plate living parts.It uses plate rollers called intaglio.These plate rollers are generally iron,copper plated and a photosensitive layer.After the small groove on the plate representing the image area is made,chrome plating is also required.
The plate roller of gravure printing machine is usually in direct contact with the image substrate.Therefore,before the plate roller comes out of the ink tank and comes into contact with the substrate,there must be a scraper to scrape the ink on the surface of the roller,and then the oil and ink in the concave hole are transferred to the substrate through the pressure of the impression roller and the capillary action of the substrate.Gravure printing machines are mostly roller type printing machines,which use continuous printing.
Gravure ink is generally solvent type.At present,there is a trend to use water-based ink,but the process running speed using solvent ink will be much faster than of water-based ink,because the volatilization of solvent is conducive to the drying of ink.Generally,the printing color used in the gravure printing process is 8-10 colors higher than that of the gravure printing.The printing process generally includes the substrate,plate roller,impression roller,ink system,ink viscosity control,solvent recovery system and drying furnace;Online cutting and stripping device,quality control system,to get the final product.
The printing material will affect the printing process:for example,how the ink is transferred to thesurface of the substrate,how the ink is on the surface of the substrate,how the ink is on the surface of the substrate,how the ink is dry or absorbed on the surface how the printing machine operator controls the registration,etc.Common substrates are coated,uncoated paper,cardboard,food packaging paper,aluminum foil and metal paper.Less commonly used are cellophane,polyurethane and fabrics.Gravure proofing is generally carried out online,and sometimes a proofing machine is also used.
Intaglio is made by engraving or etching.After chrome plating,the hardness of the plate will be increased to improve the resistance to India.The engraving or eyching depth and shape of the plate used by solvent based ink will be different from that of the water-based ink plate.Generally,when water-based ink is engraved on the plate,the circumference of the plate roller is determined by the size of the printing machine and the printed text.
According to different intaglio printing machines,there are two types of plate rollers:aluminum copper plating and iron copper plating.When preparing the plate,the roller is heated in hot water,and then put into chloric acid solution to peel off the chromium layer and embroidery layer.Then rinse it clean,nickel the iron bar to stabilize the copper coating,and zinc the aluminum roller to achieve the same purpose.Before copper plating,the aluminum roller must be treated with cyanide.After engraving,the process is chrome plating and ready for proofing.
There are several methods to solve the pollution caused by gravure printing.Each method should ne considered in terms of cost and resource consumption.The printing personnel shall establish cooperative relations with their main raw material suppliers so that the suppliers can provide the required technical support in time,ensure the quality of high-quality products and reduce pollution and waste as much as possible.Use a shallower ink tank and improved blade technology to reduce the amount of ink.Steam recovery system is the method to minimize solvent type pollution.
In many equipment improvement methods can reduce pollution.Gravure printter manufacturers use new technology for their machines and install several process improvement control accessories on their equipment.The use of vegetable oil instead of gasoline as solvent and the use of water-based ink will reduce environmental pollution,and it is also a good method to use less polluting solvent materials to replace the current solvent.
