Xerox Corporation

William D Fender

Eddie M Zanrosso

Lothar S Jeromin

Algird G Leiga

Gordon Sohl

Phillip G Perry

Robert Manchego

Robert C Speiser

Hans P Ceelen

Gerhard K Kramer

In a xerographic image, where a darker area is separated by a lighter area across a sharp boundary, there is an edge enhancement effect where there will be a black outline around the darker area and a white outline around the lighter area. In x-ray mammography, the effect is that the skin line will be darkened for a positive image and lightened for a negative image, and a loss of detail at the skin line will result. To increase visible detail at the skin line without increasing the radiation, a recharging scorotron can be used between the imaging and toner stations to recharge back to a low level of charge only those areas of the latent image that have been fully discharged. All other areas are allowed to remain unchanged. The result is a reduction of skin line deletions at a reduced x-ray exposure. Such a scorotron, in the shape of a box around the corona wires, can be constructed using a conductive top, insulative sides and a screen bottom. The top is held at approximately 200 volts, and the screen, made of fine wire, closely spaced, is held at about 40 volts. The distance from screen to photoreceptor is about 0.06 inches.

Background recharging scorotron

An x-ray photoreceptor for use in a xerographic system having a high arsenic layer 5 to 40 microns in thickness between the substrate and the selenium layer for trapping positive charge injected from the interface. Since this positive charge otherwise tends to discharge a negatively charged plate, the provision of this trapping layer will allow the plate to be used for either positive or negative charging.

Negative charging selenium photoreceptor

A method for vacuum depositing a selenium-arsenic coating on a substrate to form a photoreceptor by evaporating selenium with an arsenic concentration of 0.1 to 0.6 percent by weight and discontinuing the evaporation when the weight of the selenium alloy remaining is 2-10 percent of the original weight.

Process for manufacturing an improved selenium alloy x-ray imaging

A selenium alloy electrophotographic imaging member having an optically transparent NESA coated substrate. An x-ray image is formed from the side of the photoreceptor opposite the transparent substrate and then is scanned from the back side through the transparent substrate with a fine beam of light, the position of which is precisely monitored. The ensuing discharge from the light beam is detected by a non-contacting x-ray transparent electrode located on the outer side of the photoreceptor, away from the substrate, which reads the discharge signal through capacitive coupling, pixel by pixel, according to the position of the light beam, to form a high resolution raster pattern digital readout of the image.

Selenium alloy x-ray imaging member on transparent substrate

A process modification for the development of x-ray electrophotographic images with selenium photoreceptors wherein the occurrence of a catastrophic spot producing artifact called fatigue is eliminated. The process change consists of the addition of a photoreceptor pre-charging step immediately after thermal relaxation and before insertion of the photoreceptor in the elevator where it may be subsequently discharged by a suitable light source within thirty seconds of the pre-charging step. The effectiveness of the pre-charging step is achieved through field assisted detrapping of interference defect site injected holes which would otherwise detrap in the image charging step, thereby producing the fatigue artifact.

Precharging of the X-ray photoreceptor to eliminate the fatigue artifact

A planar electrophotographic imaging member comprising a magnetically attractable, electrically conductive layer, a thin aluminum layer, an aluminum oxide blocking layer and at least one x-ray photoconductive selenium alloy insulating layer. This planar electrophotographic imaging member may be fabricated by providing a planar substrate comprising a magnetically attractible, electrically conductive layer and a thin aluminum layer bearing an aluminum oxide blocking layer, mounting the substrate on a magnetic support member, the blocking layer facing away from the magnetic support member, and applying at least one x-ray photoconductive insulating layer to the blocking layer. The planar electrophotographic imaging member may be overcoated while the substrate remains mounted on the magnetic support member.

Magnetic imaging member and fabrication process therefor

An electrophotographic imaging member comprising providing a conductive substrate, an alloy layer comprising selenium doped with arsenic having a thickness of between about 100 micrometers and about 400 micrometers, the alloy layer comprising between about 0.3 percent and about 2 percent by weight arsenic at the surface of the alloy layer facing away from the conductive substrate and comprising crystalline selenium having a thickness of from about 0.01 micrometer to about 1 micrometer contiguous to the conductive substrate, and a thin protective overcoating layer on the alloy layer, the overcoating layer having a thickness between about 0.05 micrometer and about 0.3 micrometer and comprising from about 0.5 percent to about 3 percent by weight nigrosine. This photoreceptor is prepared by providing a conductive substrate, cleaning the substrate, heating an alloy comprising selenium and from about 0.05 percent to about 2 percent by weight arsenic until from about 2 percent to about 90 percent by weight of the selenium in the alloy is crystallized, vacuum depositing the alloy on the substrate to form a vitreous photoconductive insulating layer having a thickness of between about 100 micrometers and about 400 micrometers containing between about 0.3 percent and about 2 percent by weight arsenic at the surface of the photoconductive insulating layer facing away from the conductive substrate, applying thin protective overcoating layer on the photoconductive insulating layer, the overcoating layer having a thickness between about 0.05 micrometer and about 0.3 micrometer and comprising from about 0.5 percent to about 3 percent by weight nigrosine, and heating the photoconductive insulating layer until only the selenium in the layer adjacent the substrate crystallizes to form a continuous substantially uniform crystalline layer having a thickness up to about one micrometer.

Selenium alloy imaging member

Asynchronous high-speed film transport apparatus wherein supply and take-up reels have opposite ends of an elongated film wound thereupon. A pair of drive motors one for each reel is selectively operable to rotate the reels respectively to move film along a path from one reel to the other. First and second film vacuum chambers are associated respectively with the supply and take-up reels, each chamber being arranged to hold a loop of film, the chambers being positioned adjacent the film path between the reels. Means are connected to the drive motors for producing movement of the film and sensing means are provided for maintaining a predetermined loop of film in each of the chambers during film movement. Between the first vacuum chamber and a read/record station is a first clamp for the film and a storage device for controlling the film advance, the storage device including a movable member for controlling the length of a frame. A second film clamp is positioned opposite the read/record station. Before frame advance, the second film clamp is closed and the first clamp is opened. Film is then pulled from the film loop formed in the supply reel vacuum chamber by applying air pressure and/or vacuum to the film in the storage device. At the same time, the movable member in the storage device, or film advance cavity, is positioned to provide the desired film advance distance. During film advance, the first clamp is closed and the second clamp is opened. Film is then pulled from the film advance cavity into the take-up free film loop by vacuum in the take-up film loop cavity and/or applied pressure.

Growing community of inventors

Pasadena, CA, United States of America

William D Fender