Itek Graphix Corp.

Itek Colour Graphics, Ltd.

Eltra Corporation

Icg Limited

Peter J Neilson

Paul Christopher Cook

Graham A Thomson

John S Wirtz

Stephen Clifford Smith

Alan R Dresch

Nicholas P Cook

Anthony G Bach

William J Pickering

Platesetter

A rotary drum scanner comprises a rotatably mounted hub, a drum detachably mounted to the hub and an interlock mechanism which locks the hub against rotation until the drum is locked to the hub.

Rotary drum scanner

Drum scanner for color scanning

A compact rotary drum colour separation scanner includes a drum which is rotatably mounted about an upwardly extending axis which is preferably slightly inclined to the vertical. A part of the carriage carrying either a light source or reading head travels into the drum through the hub upon which the drum is mounted.

A method and apparatus for color separation scanning wherein a workpiece is movably supported and scanned by a linear detector. At least one color filter is interposed in the optical path between the workpiece and the linear detector and multiple scans are taken of a linear portion of the workpiece. The data obtained from multiple scans are averaged and stored in memory. A second memory may be provided to accept data input during a scan of a subsequent portion of the workpiece while the data in the first memory is output to a print device.

Method and apparatus for color separation scanning

An optical scanner is provided wherein each waveband, i.e. blue, green and red, is detected during successive revolutions of an analyzing drum. A variable scanning aperture disc selectively transmits a different image portion during each waveband scan so that the image portion detected during each waveband scan is transversely displaced along the axis of the analyzing drum. The transverse distance of optical image portion displacement corresponds to and corrects for the transverse distance travelled by the optical scanning head during one revolution of the analyzing drum. Magnification optics are also provided for, inter alia, adjusting the transverse displacement of the image portions.

Optical system for stagger compensation in an optical scanner

A dot generator system is provided wherein an LED microchip array having staggered rows of LED's imaged onto the surface of a rotating exposure drum is controlled to create a multiple exposure beam microdot image on the drum surface in a microdot line by microdot line and scanline by scanline exposure scan. Picture values are compared to microdot density values recalled from a dot density profile array using address values incremented with microdot, flyback and scanline increment values in order to produce exposure data bits indicating whether each active LED on the array is to be turned on. Exposure data bits are accumulated into an exposure data word equal in length to the number of active LED's on the LED array and stagger compensation time delays are applied to exposure bits corresponding to the second and subsequent staggered LED rows to create a timed microdot line exposure on the drum surface.

High resolution halftone dot generator system including LED array

Four color separations are produced from a single full-color photographic transparency. The transparency is mounted on the transparent curved surface of a rotatable cylinder and light is directed axially into the cylinder and out through the transparency to a photomultiplier. The illumination of the transparency is provided by red, blue and green light in time sequence, and the itensity from each color is stored separately while the transparency is being scanned and used to produce the separations contemporaneously on photosensitive paper on a second cylinder. The transparency is scanned axially of the first cylinder, which is rotated. The relative speed of rotation of the cylinders is used as a control of the magnification of the reproduced separations. A further photomultiplier is used to provide unsharp masking, and color correction is applied between the color intensities detected by the photomultiplier.

Growing community of inventors

Stroud, United Kingdom

Peter J Neilson