| 摘要 |
PURPOSE:To light an original to the sufficient quantity of light and to speed up the lighting, and to prevent the wall of a flash bulb from being stained by specifying the magnitude of a discharging current flowed every time a flash lamp is turned on and its half-value pulse width (pulse width at the time of the half of current crest value). CONSTITUTION:The flash lamp L used as a light source for lighting is constituted by sealing an anode 2 at one sealed part of a glass-made flash bulb 1 charged with inert gas such as xenon and sealing a cathode 4 at the other sealed part through an electrode support rod 3, and does not have a barium getter film made of a thin film of barium metal in the flash bulb 1. Further, a trigger electrode 5 is formed on the external wall of the flash bulb 1. In a copying method which uses a lighting device like this, the flash lamp L is put in operation on condition that the discharging current flowed every time the lamp L turns on has a half-value pulse width of <=400musec at a current crest value of >=800A. |
