Hoechst Aktiengesellschaft

Kalle, Niederlassung Der Hoechst Ag

Roland Moraw

Gunther Schadlich

Renate Schadlich

Kurt Dryczynski

Klaus Horn

Gunther Schaedlich

Helmut Walter

Peter Steinau

Manfred Unger

Gotz Von Dem Bussche

Fritz Pierson

Guenther Schaedlich

Renate Schaedlich

Adolf Rebhan

Peter P Schwierz

The present invention relates to a fixing device comprising a curved heating plate which is heated by means of a temperature controlled electrical main heating system and an electrical stand-by heating system. The main heating system comprises two heating means mounted on the underside of the heating plate, between which is disposed a bar- or plate-shaped stand-by heating means.

Fixing device

Disclosed is a method of manufacturing multilayer identity cards by electrophotographically reproducing identity information on a card core material and then laminating protective film on both sides of the core material. In preferred embodiments, the core material itself may be made up of several layers with additional security markings thereon. A relief grid image or a hologram can be inserted into the card core prior to lamination. In a further embodiment, after lamination, the identity card blank is photomechanically scanned and positioned in accordance with existing control marks and punched to produce the finished identity card.

Process for the manufacture of identity cards

Method and apparatus for electrophotographically utilizing a textured photoconductor coating and a coating carrier. Textured surface of coating can be produced by placing a textured pattern on the coating directly, or on the coating carrier. In the latter case, the pattern on the coating corresponds to that of the underlying carrier. The coating is electrostatically charged and exposed to produce an image thereon. The image is rendered visible by a liquid developer and transferred to a copy carrier. The photoconductive coating is thereafter freed from toner residues and residual charges.

Electrophotographic recording process and photoconductive coating

In the device and method of the present invention, a stripping roller is positioned a short distance from an electrostatically charged photoconductor surface in an electrophotocopy machine. The roller is supplied with a bias voltage which has a polarity the same as that of the charge on the photoconductor surface and a magnitude which is equal to or higher than that of the photoconductor surface charge, but greater than 1 kV. The photoconductor surface is moved past the stripping roller to remove excess developer liquid.

Device and method for stripping developer from a photoconductive surface

In the method and apparatus of the present invention, a voltage of up to 1,800 V is applied to the photoconductor surface of the drum of an electrophotographic copier. A latent charge image is formed by exposing the photoconductor surface and the latent charge image is developed by contact with a developing liquid to form a toner image. Excess developer is removed by a stripping roller which contacts the drum and rotates at a speed which is up to 20% faster than that of the drum.

Device and method for stripping developer liquid from a photoconductive

A process for transferring a pigment image, produced by treating an electrostatic charge image with liquid developer, from a charge image carrier to a copy carrier with the aid of an electric field, the liquid developer layer having a pigment distribution arranged according to the image, being transferred across a small air gap, preferably having a width of 5-50 .mu.m.

Process for transferring a pigment image using a spacer

A process is disclosed for thermally fixing on a support a latent electrostatic image which has been rendered visible by means of a suspension developer by applying heat and vaporizing the developing liquid, in which process the evaporating developing liquid is sucked off, condensed, separated and collected.

Process and apparatus for thermally fixing toner images

Disclosed is a method and apparatus to facilitate the method of discontinuously laminating at least two thermoplastic layers together. The layers are heated and pressed together over all but a selected window portion of the layers to facilitate lamination between the layers at all points except the selected window portions. Relief grid images can be embossed in the selected window portion or holograms or other difficult to forge inserts can be provided in these window areas prior to lamination. During lamination, the reduced or absence of heating in these window portions permits lamination of the card without destruction of the selected window portion insert.

Method for selective lamination of thermoplastic layers

Disclosed is a fixing device for an electrophotographic copier, comprising a heater plate for fixing the toner image of a recording support passing over the surface of said heater plate. The heater plate comprises a multiple-layered laminate including a contact layer for contacting the recording support; a heating layer; and at least first and second heat-insulating layers, one provided on either side of the heating layer and being selected so as to provide for a lower heat capacity of the heater plate during the heating-up operation and until it reaches the working temperature than the heat capacity during continuous operation. The device comprises a heat accumulating layer, and the first insulating layer is adjacent to the contact layer and the second insulating layer is in contact with the heat accumulating layer. The heat transfer coefficient of the first insulating layer is higher than the heat transfer coefficient of the second insulating layer.

Fixing device for copier

A method and an apparatus for charging a dielectric layer electrostatically to a predetermined potential. An AC electrode is arranged at a distance from the dielectric layer and connected to one output of an AC voltage generator. The AC voltage generator has the other output connected to an output of a DC voltage generator. Between the AC electrode and the dielectric layer there is a DC electrode which is connected to the other output of the AC voltage generator. The dielectric layer rests on a counter-electrode which is connected to the other output of the DC voltage generator and is at ground potential. Each of the electrodes can comprise one or a plurality of mutually insulated single electrodes.

Method and apparatus for electrostatically charging a dielectric layer

An original information carrier is disclosed which comprises a recording layer applied to a carrier material. The recording layer contains information in the form of a relief image which is made of relief part-images which border on one another without overlapping. The recording layer further comprises a relief grating of different grating depths superimposed over the areas of said relief part-images. A process for producing an information carrier is disclosed which comprises exposing a recording layer through separate color separation originals, exposing the layer to a grating pattern, and developing the exposed recording layer. A process for forming a matrix containing the information stored on an information carrier is disclosed which comprises forming a layer of material on the original information carrier and then separating the layer from the carrier. The separated layer of material may then be used to make additional copies of the original relief image by contacting it with transparent deformable materials. Also, an information carrier which is a copy of an original information carrier is disclosed which is made of a deformable material having the relief gratings and part-images of the original embossed therein.

Information carriers, method of forming and copying said carriers

A process and apparatus for rendering visible an electrostatic charge image. The visible image is formed on the surface of a liquid by positioning a charge image adjacent the liquid at distances of about 10 to 1,000 .mu.m from the surface of the liquid without contacting the liquid.

Process and apparatus for rendering visible charge images

An electrophotographic copying process is disclosed comprising the steps of performing a cleaning operation on a recording element by carrying out at least one rinsing operation of the element utilizing a first quantity of a developer liquid; performing a series of copying cycles comprising charging, exposing, developing with a liquid developer, transferring and fixing; and intermittently performing additional cleaning operations independently of each cycle of the series of copying cycles using a quantity of developer liquid which is at most as great as the first quantity.

Cyclic electrophotographic copying process

A process for reproducing the information stored on an information carrier by forming a matrix containing the stored information is disclosed, which comprises coating the original information carrier with a layer of material and then separating the layer from the carrier. The separated layer of material may then be used to make additional copies of the original relief image by contacting it with transparent deformable materials.

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Wiesbaden, Germany

Roland Moraw