Browse Prior Art Database

Paper-Position Sensor

IP.com Disclosure Number: IPCOM000064887D
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19

Publishing Venue

IBM

Related People

Authors:
Kelly, WR Mayron, H [+details]

Abstract

An optical transducer module consisting of an infrared light-emitting diode (LED) and eight silicon photo-transistors contained in a specially designed molded plastic housing can be used in a printer mechanism for automatic print alignment. The geometric arrangement of the electro- optical devices in the molded plastic housing provides for an optical resolution of 1.25 mm while using standard devices which can be mounted no closer than 2.5 mm center-to-center. The position of a paper sheet in a printer mechanism varies from sheet to sheet, resulting in misaligned printing. Due to the mechanical nature of the drive mechanism, the position of the edge of a sheet of paper is known with an uncertainty of 10 mm. The printer performance specifications require that this be reduced to 1.25 mm.