| 摘要 |
PURPOSE:To ensure favorable spread of an ink in a solid area and enhance image quality of printed matter, by irradiating an inked surface of a printing plate on a plate cylinder with light from a near infrared lamp having a major light emission wavelength region in a specified range, immediately before printing. CONSTITUTION:A near infrared lamp 5 for irradiating an inked surface of a printing plate with light of a specified wavelength at a position on the immediate upstream side of a printing position has a light emission wavelength region of 0.76-3mum. When the inked plate surface is irradiated with the light from the lamp 5, black image areas absorb the light, whereas white non-image areas reflect the light, so that the non-image areas are not heated. The inked plate surface thus heated selectively only in the image areas is brought into contact with a printing paper, followed by pressing by an impression cylinder, whereby direct printing on the printing paper is achieved. An effective light irradiation timing is after inking the plate surface by an inking roll roll and before the contact of the inked plate surface with the printing paper. By this, it is possible to obtain an excellent direct-printed matter with favorable ink spread in solid areas. |
