报纸是怎样制造的 英语作文 Ps.这是今晚的作业

From the 1970s began,the newspaper's production department began a historic change,so Linotype casting machine and the other row is widely used in letterpress printing of "hot row" machines and other labor-intensive technology is gradually being abandoned.This new technology and Fort (Johannes Gutenberg) in the 14th century used the same technique:the direct one-page coverage in a movable plate."Cold type" row of the invention is based on speed camera technology-based,this technology greatly reduced cost than letterpress printing.Moreover,more suitable for cold row had just put to use offset printing press.
Most daily newspapers are beginning to adopt some form of offset printing.This method is a photographic plate the image etched in the newspaper thin aluminum top (if there are color images on the page text or color you need another aluminum).Reverse the previous full-page layout is different now is presented on these aluminum forward layout.Other staff will be loaded to the printer on the layout.This method is called offset photoengraving,because the metal plate will not come into contact with the paper through the press,but to dwell on the image printed on the rubber roller,the roller in turn the image on the paper.