Abstract: A control circuit for a laser printer is described which utilizes a laser switching amplifier for supplying current to a laser diode, the latter being modulated by means of image signals. The control circuit has a correction circuit which compensates for the turn-on delay time of the laser diode. Preferably, the correction circuit lengthens the incoming image signal which controls the laser diode by a correction time which substantially corresponds to the time that elapses between when current is supplied to the laser diode and when the laser diode delivers its light, thereby eliminating distortion of the final image.

Abstract: An improved printing device is provided with a rotatable, cylindrical image-receiving support having a number of image-forming stations disposed along the rotational path of the image-receiving support. In each image-forming station a separation image of a required image is generated and transferred in correct registration to the image-receiving support at an image-transfer zone. Preferably, each image-forming station has a rotatable, cylindrical image-registration element and an imaging means for forming the separation image on the image-registration element. When measured along the circumference of the image-registration element in the direction of movement thereof, there is an equal distance in each image-forming station between the place where the separation image is formed on the image-registration element and the center of the image-transfer zone where the separation image is transferred to the image-receiving support.

Abstract: The present amplifier is designed in such a way that the amplifier will exhibit a linear characteristic in response to small variations of the input signal and a hard switching characteristic in response to large variations of that input signal. Due to the design of this amplifier, the output signal will generally be proportional to the input signal, but will be able to respond more quickly to a sudden increase of the input signal. The present amplifier is particularly useful in an amplifying circuit of a videoamplifier.

Abstract: An improved laser module is disclosed wherein a solid state laser is mounted on a laser holder and a lens system is mounted in a lens holder. The lens holder is movable with respect to the laser holder and is provided with a cylindrical part having a first screwthread. To achieve precise focussing of the laser, the laser holder is provided with a cylindrical recess wherein a second screwthread is provided. A cam and groove assembly is also provided in the lens holder and laser holder to prevent rotation of the lens holder. A rotatable intermediate ring is disposed between the first and second screwthreads when viewed radially. This rotatable intermediate ring is provided with an internal screwthread in engagement with the first screwthread and with an external screwthread in engagement with the second screwthread. The pitch of the internal screwthread is slightly different from the pitch of the external screwthread which enables the lens holder to be adjusted more precisely.

Abstract: The present invention provides a method and a device for printing images on halves of both sides of a group of receiving sheets by passing each sheet seriatim four times directly in succession through a printing station thereby printing the four halves of the sheet. The sheets thus printed are together folded double to form a book in which the sequence of the images corresponds to the sequence of the original images.

Abstract: The present invention provides a method and a device for printing images on halves of both sides of a group of receiving sheets by passing each sheet seriatim four times directly in succession through a printing station thereby printing the four halves of the sheet. The sheets thus printed are together folded double to form a book in which the sequence of the images corresponds to the sequence of the original images.

Abstract: Method for the generation of line segments having a specific thickness and having round extremities on a homogeneous raster, the raster points of which form a number of parallel raster lines, between a start point and an end point, the line segment being stored in a bit map memory in the form of a large number of image points or pixels, comprising: the determination of the coordinates of the center points of the line segment in the consecutive raster lines; the generation of a disc having a diameter which corresponds to the thickness of the line segment: and the placing of the bit-representation of the disc at the start point of the line segment in the bit-map memory, the center point of the disc corresponding to the coordinates of the start point of the line segment.

Abstract: An improvement in an office automation system for composing and printing text such that when the presence of an operator is required at the printer, the operator can instruct the system to delay the printing action and wait for a command to start printing. The start command may be generated by the printer itself, when a certain required action has been performed, or by the operator, by means of keying in a code at the control panel of the printer. A display at the control panel of the printer may show a message related to the cause of the delay.

Abstract: An exposure device for the image-wise exposure of a photosensitive layer by means of an LED array, whereby the cumulative loading of each LED over a specific time interval is determined, and on the basis thereof in a correction interval each LED is subjected to a specific extra loading equal to the difference between the maximum LED loadings and the subject LED cumulative loading so that at the expiration of the correction interval all the LED's have experienced equal aging.

Abstract: A device for discharging sheets has a holder for a stack of sheets such that the stack is pressed against a conveyor roller disposed at a fixed location above the holder. The holder is pivotably secured to a movably mounted support with the pivot axis being parallel to the roller axis and being situated between the roller and the center of gravity of the holder and straight beneath the center of gravity of the stack. Springs are connected to the support which exert an upwardly directed force on the holder. As a result of this configuration, the stack, irrespective of its size, is pressed against the conveyor roller with a substantially constant force and the sheets are discharged in substantially the same direction.

Abstract: A process for forming a visible image in which an electrophotographic element having a homogeneous and amorphous silicon layer as the sole photoconductive layer is provided with a charge image and the charge image is developed by a developing powder. The electrophotographic element has a very thin silicon layer with a thickness between 0.5 and 3 .mu.m and a dark decay time greater than 25 seconds. The photoconductive layer is developed by a one-component developing powder having a resistivity of less than 10.sup.5 ohm.meter.

Abstract: A copying machine provided with an optical system having a variable imaging ratio and a fixed distance between the image plane and the object plane and a lens whose focal length can be adjusted to the selected imaging ratio by rotation of a toothed ring coupled to the lens. Displacement of the lens with respect to the object plane and the image plane, in order to change the imaging ratio, is converted into a rotation of the toothed ring on the lens by means of a system of cooperating gearwheels. One of these gearwheels has at least one toothed ring segment which is pivotable about an axis; situated almost at the circumference of the gearwheel and extending axially of said gearwheel. The toothed ring segment can be caused to pivot about the axis and be fixed in any position.

Abstract: The present invention provides a method and a device for printing images on halves of both sides of a group of receiving sheets by passing each sheet seriatim four times directly in succession through a printing station thereby printing the four halves of the sheet. The sheets thus printed are together folded double to form a book in which the sequence of the images corresponds to the sequence of the original images.

Abstract: A new family of compounds known as dioxaphosphorinanes having the formula: ##STR1## wherein, M represents a hydrogen atom, a metal ion or an ammonium ion; R1 and R2, individually, represents a hydrogen atom, a halogen atom, an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms or a nitro group or, together, represent a methylene dioxy group; and R3 and R4, individually, represents a halogen atom, an alkyl group having from 1 to 4 carbon atoms or a hydrogen atom so long as only one of the groups R3 and R4 represents a hydrogen atom or, together, represent a cyclohexyl group.A method for preparing these dioxaphosphorinanes by reacting phosphoryl chloride with a substituted 1-phenyl-1,3-dihydroxypropane is described. Also described is a method for resolving the new dioxaphosphorinanes into their optical isomers by reacting them with an optically active amino-compound.

Abstract: An apparatus for collecting sheets of different lengths in a tray having first and second parts and wherein the second part of the tray consists of a first portion which adjoins the first part and from there extends downwardly to receive the trailing part of sheets of intermediate lengths, and a second portion which adjoins the bottom point of the first portion and from there extends upwardly in order to receive the trailing part of sheets of longer lengths than the intermediate lengths.

Abstract: A medium to be charged is conveyed past a corona charging device, so that charge emitted by the corona charging device is deposited on the medium surface. A measuring wire disposed between the medium and the corona charging device, but positioned near the medium, collects a part of the emitted charge. A first measuring circuit is used to determine a measure i.sub.d of the charge current collected by the measuring wire. A second measuring circuit determines a measure i.sub.f of that part of the emitted charge current that flows to the medium. In accordance with a predetermined relation, a value E of the surface potential is derived from these measures i.sub.f and i.sub.d.

Abstract: A copying machine is provided with a sheet stapling device for both automatically fastening together in a corner area a bundle of sheets successively printed in the copying machine and fastening together a bundle of sheets manually inserted in an externally accessible opening formed in the side of the stapling device. Preferably, the opening is formed by an elongated slot which extends to the operating side of the copying machine and which coincides with the opening through which sheets printed in the copying machine are discharged from the stapling device. A bundle of sheets can be inserted in the opening so that any edge part is under the stapling means. Thus, the inserted bundle can be stapled at different places along any edge. The opening is provided with two detectors to determine when a bundle of sheets inserted manually is correctly positioned under the stapling device and to initiate the stapling action.

Abstract: The invention provides a method for reconstructing a dither matrix, used to transform a rastered gray-level image into an image of binary pixels, from the dithered image. The method includes the steps of determining the dimensions of the dither matrix from the spatial frequencies present in the dithered image and then determining the threshold values of the dither matrix from the distribution function of the pixels having a specific value.

Abstract: Apparatus and method for printing information by a raster output scanner adapted to form an image on an image-forming medium which has fixed imaging sections, and thereafter transferring the image to a receiving sheet at a repetition frequency corresponding to one machine cycle time (T). The front-end processor of the apparatus is adapted to postpone a set-up-page signal one or more whole multiples of a machine cycle time (T) by means of a prediction algorithm stored in a memory on the basis of coded signals.

Abstract: A device for holding, adjusting and driving a rotatable body such as a polygonal mirror or a polygonal mirror firmly attached to a bushing is disclosed. The rotatable body has a central bore which encloses an axis of rotation and is provided with a means for connecting the rotatable body to the axis of rotation. The means for connecting the rotatable body to the axis of rotation comprises a first fastening zone wherein the rotatable body is rigidly connected to the axis of rotation by an interference fit and a second fastening zone located at a distance from the first fastening zone on the axis of rotation, wherein set screws spaced at regular intervals over the circumference of the rotatable body and are used to position the rotatable body relative to the axis of rotation. Preferably, the central bore of the rotatable body in the area of overlap has a diameter larger than the diameter of the axis of rotation contained therein other than in the first fastening zone.