Halftone Dot Generation in Color and Monochrome Scanners

This paper describes dot generation in Dainippon Screen's color and monochrome scanners. The optical systems for halftone dot exposure, particularly the recording head with built-in laser, in the various Direct Scanagraph color scanners are described, and the halftone dot formation, composed of approximately 23 x 23 minute dots, and its advantages in halftone dot quality and tone reproduction are discussed. The importance of the advantages in reproducing tones through certain types of halftone dots and in simultaneously outputting images and linework through a page make-up system is also explained. The optical system for dot exposure in the Scania monochrome scanner and the relation between CCD input scanning and laser output recording are also described, and the halftone dot formation, composed of fewer minute dots than those of the color scanners, and the tone reproduction are discussed in comparison to those of the color scanners. advantages in halftone dot quality and tone reproduction are discussed. The importance of the advantages in reproducing tones through certain types of halftone dots and in simultaneously outputting images and linework through a page make-up system is also explained. The optical system for dot exposure in the Scania monochrome scanner and the relation between CCD input scanning and laser output recording are also described, and the halftone dot formation, composed of fewer minute dots than those of the color scanners, and the tone reproduction are discussed in comparison to those of the color scanners.