Apparatus for imaging text and graphics on photosensitive material

摘要

Image setting apparatus is disclosed for producing two-dimensional images on photosensitive sheet material. The apparatus includes a device for transporting the photosensitive sheet material past an image point to provide a first dimension of the two-dimensional image; a light source for producing a modulated beam of light, a scanning device for converting the light beam into a scanning beam; and a scan lens in the path of the scanning beam such that a focused beam spot moves repeatedly in a linear direction across the photosensitive material at the image point to provide the other dimension of the two-dimensional image. According to one improvement the scanning device is a rotatable prism having two mirror facets whose planes intersect in a common line. The prism is arranged to rotate about an axis perpendicular to this line so as to reflect the light beam into a scanning beam having a substantially constant angular velocity. According to another improvement, the device for transporting the photosensitive sheet material includes a pair of driving rollers at the nip of which the sheet material is pinched, the image point being located along a line on the surface of one of these rollers extending parallel to its axis of rotation.