Eastman-Kodak Company

David A Skye

Anthony Earle

Christopher B Rider

Paul C Ward

Nicholas John Taylor

Peter J Twist

Edward C Glover

Leslie J Pummell

Bruce S Gowans

Christopher M Graebe

Optical scanning of a moving sheet of image-bearing material is carried out in a stand-alone apparatus. No drive is provided for the sheet in the scanning apparatus, and the sheet accelerates therethrough under its own momentum and under its own weight. Transmittance scans from an optical sensor are obtained at a uniform frequency, and are analysed to determine the final speed of the sheet. Computation then allows the data to be corrected such that the detected transmittance can be related to the actual area of the sheet under acceleration. The transmittance of the sheet is then combined with its measured area to determine the amount of image present on the sheet. The invention finds application in photoprocessing apparatus, and a signal dependent on the amount of image present on the sheet and its area is sent back to the photoprocessor to control the amount of replenishment chemicals added to the processing tanks.

Determination of the speed of movement of an image-bearing sheet

A processed sheet of photographic film is guided into a channel of scanning equipment in which it is subjected to light from an elongate fluorescent tube. Light transmitted through the film is detected by a sensing arrangement in the form of an elongate solar cell strip. The strip is scored so as to divide it into 3 small subsidiary sensors and four longer sensors. All seven sensors form the main light sensor. As the leading edge of the film, which is assumed to be of uniform light density, enters the channel and totally obscures at least one of the subsidiary sensors, that sensor measures the transmittance of the film. This value, together with the reduction in light sensed by the main sensor, is then used to determine the width of the film. The film width is combined with the separately computed film length, to provide a signal used to control the amount of replenishment chemicals to be supplied to a photoprocessor.

Width measurement of an image-bearing sheet

Described herein is a buffer device for use with photographic processing apparatus which provides a buffer for solution being fed to or collected from the apparatus. The buffer device (18) comprises a flexible plastic concertina-shaped container (30) having a volume appropriate to the apparatus with which it is to be used. The container (30) is preferably constructed to be normally-closed and requires liquid pressure to open it. The container (30) is fixed at its upper end (38) and its lower end (40) is free to move downwardly when liquid enters it. An index member (32) is attached to the lower end (40) and this member (32) cooperates with a position sensor to indicate to an operator whether the container (30) is 'not empty', 'not full' or 'full'.

Photographic processing apparatus

Processing of photographic film

Automatic processing devices for processing photographic materials

Photographic film processing

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Harpenden, United Kingdom

David A Skye