International Business Machines Corporation

Lexmark International, Inc.

Randall A Maddox

Wilson Morgan Routt, Jr

Sherwood Kantor

Duane E Grant

Paul S Yosim

Edwin L Libby

Douglas J Roberts

Gerald L Cox

Joseph W Rudolph

An optical system for light scanning devices in which a beam of light travels from an origin to an object along a light path and has along that path a scan direction and a cross-scan direction. The optical system includes a light source at the origin of the light path, a polygonal reflector located along the light path and having adjacent peripheral mirror surfaces rotatable in the scan direction, and a pre-scan optical sub-system located along the light path between the light source and the polygonal reflector. The pre-scan optical sub-system includes, in order of light travel from the light source, a collimating lens and a pre-scan lens having a convex cylindrical lens entrance surface aligned in the scan direction for converging the light beam in the cross-scan direction, and a convex lens exit surface for converging the light beam in the scan direction. An aperture stop may be provided between the collimating lens and the pre-scan lens to further truncate or reduce the diameter of the collimated beam. The optical system has a post-scan optical sub-system located along the light path between the rotatable polygonal reflector and the object and including a first f-theta lens and a second f-theta lens.

Optical system for light beam scanning

Disclosed is an optical encoder structure which is easily attached to a motor case and shaft in either the factory or field, and which automatically achieves, by its construction, both axial and radial alignment. This is achieved by first securing to a housing by a novel latch, a mounting plate which is spaced a predetermined distance from the housing. A rotatable encoder disc, having a conically shaped hub is placed in an aperture in the housing, the conically shaped hub serving to self center the disc radially relative to the housing. The assembly is pushed onto the motor shaft, and the disc is secured to the shaft. The plate is then attached to the motor case and the housing rotated. This moves the housing into an abutting relationship with the plate and spaces the housing a predetermined distance from the disc. Thus the disc is both axially and radially positioned, no instruments being required to accurately position the housing with respect to the disc or motor. Moreover, so that no electrical adjustment is necessary in either the field or in the factory, the aperture for the mask or slits of the stationary member of the optical encoder and the transparent or slit openings on the rotating member are made equal to the period of the rotating disc pattern divided by two. This creates a half-wave rectified analog waveform which in conjunction with direct feedback of the voltage created by the analog waveform to control the code cycle, operational amplifier saturation is inhibited.

Modular shaft encoder

Image transferring apparatus for a continuously variable reduction electrostatic copier. A single fixed aperture is employed, adjacent the object plane, to:

Apparatus for the reduction of image intensity variations in a

Mirror multiplexor for linear image sensors

A field replaceable encoder including a slotted housing having a pair of passages therethrough essentially perpendicular to the longitudinal axis of the housing, is attachable to the frame of a machine having a rotatable shaft to which the encoder is to be mounted. Attached to the housing is an accurate stationary mask, the mask having slits which are aligned with the passages in the housing. The mask includes an accurately dimensioned aperture for locating the mask, and thus the housing, on a bearing on the rotatably mounted shaft. A pair of light sources and a pair of light detectors are mounted on opposite sides of the housing aligned with the passages and slits in the mask. A hub, to which is attached a rotating disc, is connected to the rotating shaft, the disc being mounted in the slotted housing so that interdigitated opaque and transparent portions align with the slits of the mask, and thus the light sources and light detectors. In the preferred embodiment, the light sources are mounted in the passages (tunnel like in formation) which converge at their outlets and which prevents having to employ collimated light sources while inhibiting cross-talk between the detectors and adjacent sources allowing for close spacing of the source pair and the detector pair.

Incremental rotary encoder

Dimensional variations, such as skew, alignment and abutment, in an array scanner are corrected by scanning and storing into a storage means an uncorrected electronic image generated from a test pattern. Correctional factors are generated from the stored electronic image. The correctional factors are used to correct the dimensional variations in the electronic image of the test pattern and/or dimensional variations in subsequent electronic image outputted from the scanner.

Electronic control system

An illumination system of particular use in document copiers wherein an incandescent lamp which may be of the tungsten-halogen type is located at the focal point of a reflector shaped as a conic section such as elliptical cylinder, directing light rays toward an interference filter for separating the IR radiation and redirecting the IR rays back to the incandescent lamp for heating the lamp. Both cold mirror and hot mirror embodiments of the system are disclosed.

Growing community of inventors

Lexington, KY, United States of America

Randall A Maddox