Exposure device having a movable light-attenuating filter for controlling an amount of exposure light and exposure method thereof

An exposure method of an exposure device, the exposure device comprising:

• a light source which illuminates an original;
• a light-adjusting filter which adjusts light from said light source in accordance with color of an image recorded on the original:
• illumination means which gathers at least one of light from said light source and light adjusted by said light-adjusting filter and irradiates the gathered light onto the original;
• moving means which causes at least one of said light source, said light-adjusting filter and said illumination means, and the original to move relatively during exposure to effect scanning;
• a light-attenuating filter which can move in a direction of the relative movement and has a light-attenuating region of a fixed transmittance, which attenuates light illuminated onto the original, an area of said light attenuating region gradually increasing in the direction of the relative movement;
• filter-moving means which moves said light-attenuating filter such that an amount of light illuminated onto the original becomes a target amount of light;
• an imaging optical system which causes light from the original to be imaged at the image-receiving element;
• and
• a slit which changes light imaged at the image-receiving element by said imaging optical system into slit light, said slit being formed in that a longitudinal direction thereof is disposed in a direction crossing the direction of the relative movement, said method comprising the steps of:
• moving said light-adjusting filter and moving said light-attenuating filter such that an amount of slit light imaged at the image-receiving element becomes a target amount of light in accordance with color of an image recorded on the original.

An exposure method of an exposure device, the exposure device comprising:

• a light source which illuminates an original;
• a light-adjusting filter which adjusts light from said light source in accordance with color of an image recorded on the original;
• illumination means which gathers at least one of light from said light source and light adjusted by said light-adjusting filter and irradiates the gathered light onto the original;
• moving means which causes at least one of said light source, said light-adjusting filter and said illumination means, and the original to move relatively;
• a light-attenuating filter which can move in a direction of the relative movement and has a light-attenuating region of a fixed transmittance, which attenuates light illuminated onto the original and of which area gradually increases in the direction of the relative movement;
• filter-moving means which moves said light-attenuating filter such that an amount of light illuminated onto the original becomes a target amount of light;
• an imaging optical system which causes light from the original to be imaged at the image-receiving element;
• and
• a slit which changes light imaged at the image-receiving element by said imaging optical system into slit light, said slit being formed in that a longitudinal direction thereof is disposed in a direction crossing the direction of the relative movement, wherein said light-adjusting filter has a plurality of movable filters for adjusting light from said light source, and wherein said filter moving means moves the plurality of filters and said light-attenuating filter such that an amount of the slit light becomes a target amount of light in accordance with color of an image recorded on the original, said method comprising the steps of:
• (A) calculating respective transmission amounts of the plurality of filters;
• (B) calculating an amount by which said light-attenuating filter moves on the basis of the respective transmission amounts calculated by said step (A) and moving said light-attenuating filter in accordance with the calculated amount by which said light-attenuating filter moves;
• (C) calculating respective amounts by which the plurality of filters move on the basis of the respective transmission amounts calculated by said step (A) and moving the plurality of filters in accordance with the calculated respective amounts by which the filters move;
• and
• (D) causing at least one of said light source, said light-adjusting filter and said illumination means, and the original to move relatively at a conveying speed of a value obtained by dividing a conveying speed of the image-receiving element by a latent-image enlargement ratio of said imaging optical system with respect to the original, so as to scan and expose the image-receiving element.