| 摘要 |
PURPOSE:To dispense with the press plate in offset printing, by a method wherein a plate cylinder is provided as a drum being subjected to hydrophilic treatment and a magnetic latent image is formed to the outer surface of a magnetic drum from image data and a magnetic powder is supplied to said latent image to be transferred and fixed to the plate cylinder and ink is adhered to the magnetic powder on the plate cylinder becoming the printing image part of the magnetic drum. CONSTITUTION:The digital image data inputted to an image data operating part 13 from the outside is divided into the data corresponding to the four primary colors. The image data are converted to printing image part data to be magnetized and the data corresponding thereto are sent to a magnetic head 2 to magnetize the part corresponding to a printing image part of a magnetic drum 1. When the outer surface of the magnetic drum 1 reaches a magnetic powder supply part 4; a magnetic powder is adhered and fixed only to a magnetic latent image part by the magnetic force of said drum 1. The magnetic powder on the magnetic drum 1 is transferred to a plate cylinder 8 when contacted therewith and fixed to the surface of the plate cylinder being subjected to hydrophilic treatment by a fixing roll 12. When the above mentioned operation is finished, the plate cylinder 8 passes a dampening water supply part 6 and an ink supply part 7 and the ink of the printing image part is transferred to the outer surface of a blanket roll 9 to perform printing. |
