Donald L Buddington

US Patent:

42721873, Jun 9, 1981

Filed:

Dec 17, 1979

Appl. No.:

6/104255

Inventors:

Ivan P. Birdsall - Boulder CO
Paul J. Bradmon - Longmont CO
Donald L. Buddington - Boulder CO
Vincent H. Garcia - Berthoud CO
Don S. Nelson - Arvada CO

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G03B 2734
G03B 2740

US Classification:

355 56

Abstract:

The optical elements of a copier are automatically aligned by positioning the elements under the control of signals from an image-dissecting scanner. The scanner, mounted to receive the image normally presented to the photoconductor, examines a master document placed in the position normally occupied by a document to be copied. Optical adjustments are made as a function of the examination of lines on the master document by the scanner. The contrast between a line and its background is maximum when optical elements between the master document and the scanner provide the sharpest focus of the line image to the scanner. Signals from the scanner for a plurality of lines on the master document determine optimum positioning of the optical elements. The scanner determines the apparent spacing between lines, which are a known distance apart on the master document, to position the optical elements for a desired magnification. The positions of selected lines, examined by the scanner, relative to absolute reference points are used to align the master document support for subsequent copying of original documents.