Abstract: A method and a device are provided for determining the moment that a layer of tacky material needs to be rejuvenated. Typically, the layer is present on a cleaning member for removing contaminants such as paper dust and softened toner material from a fusing surface. The method includes measuring the light reflection value of the layer of tacky material, comparing the measured light reflection value with a reference value and rejuvenating the layer of tacky material as soon as the measured light reflection value differs by a predetermined value from the reference value. The device implements the method of the present invention.

Abstract: A method and device for controlling an image forming device in which image forming stations can form an image on a medium that is advanced past these stations. For each image under formation, the positions occupied by the leading and trailing edges are registered with respect to the image forming stations. Signals for controlling the image forming stations are generated depending upon the positions registered. In doing so, the positions of the leading and trailing edges are compared with predetermined positions belonging to a first and second group respectively. If two compared positions correspond to one another, a control signal will be generated that is associated with the specific predetemined position used for the comparison.

Abstract: A printing device for recording information in the form of toner images comprising a moveable image-forming medium on a support, the surface of which forms a dielectric layer; an image-forming station disposed along the trajectory of the image-forming medium having a magnetic roller with an electrically conductive nonmagnetic outer sleeve with magnets disposed inside the sleeve; a means for supplying electrically conductive toner particles to a linear zone in the image-forming station; and a plurality of electrodes for generating an electric field corresponding to a desired image pattern, said electrodes extending in the direction of movement of the image-forming medium and disposed so as to be insulated from one another and covered by a dielectric layer wherein each electrode can be actuated by a voltage source and each electrode can generate an electric field across the dielectric layer over part of the zone wherein image formation takes place when in the image-forming station.

Abstract: A contact fixing device primarily used in electrophotographic copiers is described. It has a driven and heated fixing surface which is made from a partially resilient material and a driven pressure surface which presses against the fixing surface forming a fixing zone through which copy material can be fed for fixing a toner image thereon. It also has a hollow perforated cleaning roller which while rotating in contact with the fixing surface takes up toner from the fixing surface. To prevent contamination of the device due to toner material flowing over the ends of the cleaning roller, this roller is provided with a narrow circular thickening near each end.

Abstract: A conveyor system is described, consisting of a pair of electrically conductive rollers about which an insulating belt is trained and a static-charge eliminator. The static charge of the belt and, thus, the conveyor system is reduced by providing the electrically conductive rollers with an insulating sleeve, guaranteeing the reliable transport of the document. The conveyor system may be used in a copier for moving originals onto a glass platen or copies through the toner transferring section.

Abstract: In a reproduction device for making simplex or duplex copies having image-free side margins of the desired width, means are provided for supplying to the process control unit of the device data concerning the width of each of two oppositely situated image-free side margins of the original to be reproduced and the required minimum width of the corresponding side margins on the copies to be produced and calculating in the process control unit the imaging ratio and an adjustment or activation time of at least one of the copy forming process functions and then they control the copying process in accordance with these calculated values.

Abstract: A device for collecting sheets comprising a collecting tray and a conveyor roller for feeding sheets into the tray. The collecting tray comprises a baseplate having a distance between abutment surfaces which corresponds to a dimension of the sheets to be collected, preferably the length. The middle part of the baseplate is higher than the side parts. An abutment strip which contacts and stops the leading edge of a sheet fed into the tray is connected to an edge of the baseplate and has a surface which is cylindrically curved, the centerline of which coincides with the centerline of the conveyor roller. A wall plate is connected to the opposite edge of the baseplate and also has a cylindrically curved abutment surface, the centerline of which coincides with the line of intersection between the baseplate and the abutment strip.

Abstract: In a device for collating sheets of paper having at least one receiving surface made from electrically insulating material, a set of rolls for feeding a sheet from one side of the receiving surface and depositing it thereon and an improved charge remover for removing electrical charges from a deposited sheet comprising at least one conductor connected to earth potential which is disposed on the side of the insulated receiving surface remote from the side where the sheet enters and which forms an abutment with which the leading edge of each sheet comes into contact when it is being deposited on the insulated receiving surface, thereby removing electrical charges from the entire sheet.

Abstract: Electrophotographic copying device provided with an endless photoconductive element, means for forming a powder image on the element and an intermediate support which, under the influence of pressure, is capable of picking up the powder image from the element and then under the influence of pressure and heat, transferring the image to and to fixing it on a copy sheet. Further, the device is provided with cooling means, e.g., blower slots, for cooling that portion of the surface of the intermediate support which has not been in contact with the copy sheet.

Abstract: A device for exposing an edge zone of a photoconductive element to light comprising a light source and a moveable screen by means of which the width of the edge zone that is exposed to light can be adjusted. The light source is fixed to the moveable screen and is moveable therewith. Preferably, the screen consists of a pivotable housing in which the light source is mounted in an area defined by two planes which intersect along the bottom edge of the innermost side wall of the housing and form an angle of 15.degree. such that the plane through the pivot line of the housing and the bottom edge of the innermost side wall of the housing bisects the 15.degree. angle.

Abstract: An exposure system for imagewise exposure of a movable light-sensitive layer, dot by dot along a line on the layer, to an electronically modulated light beam such as that of a laser has a narrow slit disposed near the light-sensitive layer in the path of the light beam, the slit being made with a width less than the dimension at the slit of the light beam in the direction of slit width. In this simple way, the laser beam always describes at least one and the same imaging line relative to the light-sensitive layer, even when beam run-out occurs.

Abstract: In a conveyor device for conveying sheet material in sheet or web form, two pairs of conveyor rollers are spaced apart with their axes parallel to one another, each pair including a deformable roller cooperating with a substantially non-deformable conveyor roller, and the two pairs of rollers are driven by a non-deformable drive roller which is mounted for rotation about a fixed axis disposed between them, with the deformable conveyor roller of each pair pressed against its cooperating non-deformable conveyor roller and also against the drive roller so that compensating differences of peripheral speed occur at the two pressure nips of each deformable conveyor roller. Each deformable roller is pressed in a direction located in or at least proximate to the plane of the bisector of the dihedral angle between a plane through the axes of the drive roller and the deformable roller and a plane through the axes of the deformable roller and its cooperating non-deformable conveyor roller.

Abstract: An electrophotographic element and an indirect electrophotographic process for producing copies are described wherein the electrophotographic element contains a photoconductive pigment dispersed in a binder, the binder being a copolymer of an acrylic or methacrylic acid ester monomer, a vinyl aryl monomer, and 1% to 3% by weight unsaturated acid, such that 2.5 to 6.0 parts by weight of copolymerized vinyl aryl monomer are present per part by weight of copolymerized acrylic or methacrylic acid ester monomer. After repeated use of this electrophotographic element, the contours of smaller sized images do not become visible on larger sized images produced after the smaller images.

Abstract: A holder for a stack of sheets which can be fed therefrom in successive cycles from the bottom of the stack and returned to the top of the stack or, in the last cycle, discharged to a tray. The holder includes a separator which can be engaged between the sheets of the stack for separating returned sheets from the other sheets of the stack. A detection system is provided for detecting sheets that have been placed in the holder (for starting a first cycle) and for detecting when all of the sheets have been returned to the holder (for starting a next cycle). The detection system includes a light source and a light sensitive detector installed at the bottom of the stack. When, by the feeding of sheets, the separator reaches the bottom of the stack, the separator intercepts the light from the light source to cause a signal from the detector. This signal is similar to the signal of the detector when the holder is empty, but which signal differs from the reaction of the detector when a sheet intercepts the light.

Abstract: A device for positioning an original in sheet form on an exposure table comprising a ruler and a means for moving the ruler between a position in which an edge of the ruler extends upwardly from the exposure table for positioning and retaining a sheet original arriving along the exposure table and a position in which the original is released so that it may be displaced in the direction of and past the ruler. The exposure table has a recessed part such that when the ruler occupies the retaining position the part of the ruler bearing the retaining edge rests partly in the recessed part such that it lies against the upright wall of the recessed part and partly projects above the surface of the exposure table.

Abstract: Charge-transporting compounds which form substantially colorless layers having a minimal residual charge and a good cleanability are disclosed. These compounds are of the general formula: ##STR1## wherein R1, R2, and R3, individually, represent a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms. Also disclosed is a photoconductive element containing a charge-generating compound and a charge-transporting compound of the general formula shown above which is homogeneously distributed in a binder. The charge-transporting compounds of the general formula are very soluble in various solvents and film-forming polymers providing for great maneuverability in processing the compounds into layers.

Abstract: A colored magnetically attractable toner powder in which the individual toner particles comprise a core containing magnetically attractable material, a light-reflecting layer which envelops the core and comprises light-reflecting pigment, yellow-fluorescent dye and a binder in which the dye fluoresces, and a coloring layer which covers the light-reflecting layer and comprises yellow-fluorescent dye, optionally in an admixture with other fluorescent dye or dyes or pigments, and a binder in which the fluorescent dye or dyes fluoresce(s).

Abstract: In a contact fixing system in which a heat-softened toner image is fixed onto a sheet material by being pressed against the sheet material in a nip between the peripheral surfaces of two circulating fixing members, such as rollers pressing one against the other or a roller pressing against an image carrying belt, residues of the toner of an image and paper dust are removed from the surface of a fixing member in a cleaning zone beyond the fixing nip by moving in rolling contact with that surface a circulating cleaning surface, such as a roller surface, to which the toner adheres preferentially and which has a multiplicity of spaced-apart perforations formed therein and so disposed that with continued movements of the cleaning surface through the cleaning zone a toner layer formed on the cleaning surface is repeatedly pressed thin and excess toner present in it is displaced to the perforations for discharge through them into a cavity inside the cleaning member.

Abstract: Electrophotographic apparatus, provided with an endless photoconductive belt having a seam, said belt being taken past a number of processing stations, including a charging and a developing station, in order to form an image on said belt. An image formed is transferred onto receiving material in a transfer station. A check is made for each image to be formed to determine whether the seam is situated inside the belt section intended for forming that image. If the seam is situated inside that belt section no receiving material is fed to the transfer station and that belt section is discharged before that section reaches the developing station.

Abstract: A device for transferring an image present on a belt (1) driven at a first speed to an intermediate support (14) driven at a second speed. A pressing element (28) keeps the belt (1) and the intermediate support (14) in contact with one another during the image transfer, the belt (1) assuming the speed of the intermediate support (14) in the contact zone under the influence of frictional forces. A belt storage device (27,33) disposed between the belt drive means (7,8) and the contact zone stores the length difference arising from the difference in the belt speed at the belt drive means and at the contact zone. The belt length present in the belt storage device (27,33) is measured. The speed of the intermediate support (14) is controlled in dependence on the length measured.