Dennison Manufacturing Company

Other

Leo A Beaudet

Richard A Fotland

Donald J Lennon

Fred Miekka

Robert O Kaplan

An apparatus for charging insulating, nonmagnetic toner particles includes a semiconductive, elastomeric toner applicator roll in rolling contact with the dielectric or photoconductive drum which carries the electrostatic image to be developed. Toner is metered onto the surface of the toner roll and tribocharged, and the toner-bearing roll is rotated past a field electrode which repels airborne toner back to the toner applicator roll. A vacuum housing is placed in proximity to the field electrode to collect airborne toner. The field electrode is maintained at a direct current potential which is below the value required to cause corona discharges to the toner roll surface.

High speed apparatus for developing electrostatic images using single

Method and apparatus for charged particle generation, particularly for use in electrographic imaging, in which charged particles are generated in a discharge region and extracted to form an electrostatic image, wherein a controlled gas is introduced into the discharge region for improved operation and service life. The controlled gas may consist of nitrogen, an elemental noble gas (or mixture of such gasses, or a mixture of nitrogen with one or more noble gasses. In the preferred charged particle generator designs, a high voltage alternating potential (drive voltage) is applied between driver and control electrodes separated by a solid dielectric member to induce glow discharges within apertures in the control electrodes. The charged particle generator may include only the driver and control electrodes, or may further include screen electrodes to regulate the extraction of charged particles. Injection controlled gas into the various discharge sites dramatically reduces the threshold voltages for charged particle generation as well as the corrosion and fouling of electrodes and dielectrics, providing a more durable device and improved electrographic print quality. Nitrogen and nitrogen-argon mixtures are preferred, particularly nitrogen-argon mixtures of about 2:1 volume ratio. The controlled gas may be injected at relatively low concentrations with advantageous results, as well as at higher concentrations.

Method and apparatus for charged particle generation

Electrostatic transfer imaging in which a latent electrostatic image is formed on a dielectric image roller, toned, and transferred to an image receptor medium. The dielectric roller contacts a transfer roller, and receptor sheets are fed between the two to receive toner images. Image transfer is effected with simultaneous fusing using high pressure between the rollers, which are skewed for enhanced efficiency of toner transfer. The rollers are skewed, preferably at an angle in the range 0.5 degree to 1.5 degree. Receptor sheets adhere to the surface of the transfer roller in preference to that of the image roller, thereby creating a relative motion between the dielectric surface and receptor sheet. This surface motion differential considerably improves the efficiency of toner transfer from the image roller to the receptor sheet, thereby reducing residual toner on the image roller.

Pressure transfixing of toner images using skewed rollers

An imaging member employed in the high temperature transfer of toner onto paper. The imaging member operates at temperatures above the melting temperature of the toner by sealing the porous structure of the imaging member with a material having suitable dielectric, thermal and fluid release properties.

Process electrostatic imaging and developing

An ion generation system employed in forming electrostatic images on a dielectric surface in which compensation is made for variations in the electrostatic images. The desired compensation is accomplished by spacial or electrical adjustments of electrode apertures, or by adjusting their relation to the dielectric cylinder, so that more uniform electrostatic images are produced.

Ion generation compensation

An electrostatic toning system employed in applying toner to latent electrostatic images on the surface of a dielectric material. Toning is accomplished by fluidizing the toner in a gaseous stream, charging the toner in the fluidized bed, and conveying the charged toner to the dielectric surface by means of a toner receptive member in contact with the fluidized toner.

Electrostatic toning

Dielectric sealing of porous anodized aluminum, in which moisture in the pores of the oxide coating formed by hardcoat anodizing is removed, and the porous anodized surface then impregnated with a dielectric wax. Suitable wax sealants include Carnauba and Montan waxes. The anodized member is preliminarily heated to a temperature in the range 120.degree.-180.degree. C. in order to drive off moisture and other substances from the pores. This heating process may be continued for the purposes of impregnating the pores with the wax sealant, which is applied as a hot melt. Alternatively, the preliminary dehydration is achieved simply by heating the member to the impregnating temperature, with no separate dehydration stage. Any excess material remaining on the member's surface is removed. The resulting product has excellent resistivity and dielectric properties, and maintains these properties at elevated humidities. After removing material from the member's surface, the member may be polished to a better than 20 microinch finish, achieving favorable toner release characteristics where the member is used for pressure transfer of a toner image.

Process for making electrostatic imaging surface

Dielectric sealing of porous anodized aluminum, in which moisture in the pores of the coating formed by hardcoat anodizing is removed, and the porous anodized surface then impregnated with a water insoluble metallic salt. The impregnant material is a compound of a Group II or III metal with a long chain fatty acid containing between 8 and 32 carbon atoms, saturated or unsaturated. The impregnant material may be applied as a hot melt or in solution; in the former case, any excess material is removed from the surface. The resulting product has excellent resistivity and dielectric properties, and maintains these properties at elevated humidities. As a final step the surface may be polished to provide favorable toner release characteristics during pressure transfer.

Anodized electrostatic imaging surface

Method and apparatus for ion generation with enhanced performance through operation at elevation temperatures. A glow discharge ion generator is subjected to extrinsic heating, both preliminarily and during continued operation, thereby providing increased ion current outputs. Such thermal control additionally prolongs the life of the ion generator by reducing corrosion and contaminant buildup.

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Milford, MA, United States of America

Leo A Beaudet