Abstract: An active switching mechanism is used for diverting paper sheets from a first area (A) to either possible paths (ab or ac). The sheets along the first path (ab) can be directly conveyed to a second area (B), and the sheets along the second path (ac) can be directed through a passive switching mechanism (4) to a third area (C), the direction of the moving sheets being reversed through a reversing mechanism, thereby enabling said sheets to be conveyed in the reverse direction from the third area (C) along a third path (cb) to the second area (B), using a passive switching device (4).

Abstract: In a printing method and system for production of a print image on a carrier material, a print carrier is provided, a surface of which is charged with water vapor at locations corresponding to structures of the print image to be printed. Water vapor is condensed at these locations as a film of water. Ink is applied to the surface, the ink adhering to non-wetted locations and not being accepted by the wetted locations. The ink from the non-wetted locations is printed onto the carrier material.

Abstract: A unified bus system is used for communication in a printer or copier apparatus. Each functional unit of the printer or copier apparatus is connected to the bus by an interface. The interface includes a duel-port RAM memory unit in which data messages associated with the specific functional unit or sensors in the printer or copier apparatus are stored. The functional units are notified of the presence of new data or messages on demand so that each functional unit has an overall picture of the functional status of the printer or copier.

Abstract: A character generator for a printer or copier which illuminates a surface of a photoconductor is provided with a cooling device, wherein a line of LEDs is mounted on a bearing surface of a hollow, thin walled profile that runs along the direction of the LED row. The hollow interior is filled with a liquid. On the other side of the hollow profile from the row of LEDs is a heat dissipating structure, such as a finned heat sink.

Abstract: In an electrographic printer or copier using an LED for exposing the photoconductor, an arrangement of two disconnectable flat conductors are provided which form part of the electrical connection between a current supply and an exposure system. A first flat conductor contains a first current carrying metal strip, at least one second current carrying metal strip which has at least sections thereof in parallel to the first metal strip, and at least one insulating strip which insulates the second metal strip from the first metal strip. The first flat conductor provides a connection with the second flat conductor which has the first metal strip protruding beyond the insulating strip. The second flat conductor has essentially the same geometrical structure as the first flat conductor at least at the connection point.

Abstract: An apparatus for transporting a band-shaped recording medium in an electrographic printing or copying device, includes a drive cylinder, a pressure cylinder mounted displaceably relative to the drive cylinder, and a pressure spring effecting a contact pressure of the pressure cylinder on the drive cylinder, wherein the recording medium is transported between the drive cylinder and the pressure cylinder by friction, and the drive cylinder adjoins the recording medium with a contact surface, and wherein the force effect of pressure spring is divided into a first, radial force component acting perpendicularly to the contact surface and a second force component received by a guide face guiding the pressure cylinder.

Abstract: A method for operating a printer or copier is disclosed.

Abstract: A printer or copier has an optical character generator for reproducing raster image data in grey-scale displays. Integrated light sources in the form of LEDs arranged in arrays are aligned to form a print line. A control IC is provided for each LED array. Groups of the control ICs are formed in which information is shifted for the switch on time of all LEDs of a group starting with the first control IC to the next IC. The ICs are connected together by bonding. A ramp circuit is provided to prevent current surges when the LEDs are switched on. A flat unit that extends along the character generator is used to transmit information and power to the control ICs. Busbars ensure that power is provided to the LEDs.

Abstract: A fixing station for fixing toner images on a carrier material is provided in a printer or copier. A flap or shutter mechanism having a plurality of flaps or shutters that are pivotable into an open and into a closed position are arranged between a heat radiation source and the carrier material for controlling fixing of the toner to the carrier material.

Abstract: A printer or copier optimizes half tone printing by a method including printing a raster toner mark and scanning the raster toner mark to determine if it is in the parameters for optimum half-tone reproduction. The raster toner mark has pixels with toner and pixels without toner. If the optical density of the raster toner mark is below a lower limit, the bias voltage between the photoconductor and the developer station is increased so long as the current bias voltage is below an upper limit. The optical density may also be increased by increasing the ratio of toner mixed into the carrier particles. If the raster toner mark is above the target optical density, the bias voltage is decreased (if it is above a minimum level) and/or the ratio of toner to carrier particles is decreased. The combined effects of adjusting toner/carrier ratio (a slower process) with adjusting the bias voltage (a faster process) provides optimization of the half-tone printing.

Abstract: A detachable coupling is provided for transmitting mechanical rotation from a driving shaft to a driven shaft which extend substantially coaxially with one another. A spring apparatus is provided in the detachable coupling which acts axially and is rigid in the direction of rotation. The spring apparatus presses wedge-shaped catch slots of the detachable coupling in an axial direction against catch pins in the shafts.

Abstract: A printer or copier which operates by transfer printing has a fixing roller for affixing toner to the recording medium. A release agent, or parting oil, is applied to the roller by a dosing tube having openings through which the release agent flows to a wick. An application element is moved over the roller between the wick and the roller for cleaning and application of the release agent. The wick is held in guide elements and the lower guide element has a duct for collecting excess release agent and applying it to the application element.

Abstract: In a device for transporting and temporarily storing a web-like recording medium in an electrographic printing or copying device, the recording medium is fed with a roller arrangement to a temporary storage unit by use of friction. A loop forming in the temporary storage unit is adjusted by a pendulum. When the pendulum is nearing a vertical position, tension on the recording medium is decreased to such an extent that the roller arrangement feeding the recording medium no longer has frictional driving engagement with the recording medium so that feed of the recording medium substantially ceases. When the pendulum is moved away from the vertical position towards a horizontal position as a result of the loop in the temporary storage unit being decreased, tension stress in the recording medium increases and frictional engagement at the roller arrangement increases so that the recording medium is then fed by the roller arrangement.

Abstract: A printer for printing endless paper webs on both sides has two printing stations with a web turnover station therebetween. The paper web is fed in parallel side-by-side to the two printing stations which are on the same rollers. The drive of the web through the printer is by a positive drive, using pins to engage holes in the paper web, for example, into the first printing station. The drive of the paper web thereafter is by friction drive to permit slippage in the drive to compensate for variations in paper length during heating, etc. The slippage is controlled by brakes or other drag inducing devices acting on one or both of the two portions of the paper web.

Abstract: A method and apparatus for operating stepping motors in a printer or copier senses temporarily changes in the moment of resistance caused by the introduction of the leading edge of the paper and overcomes this change in moment by changing the current amplitude to the motor windings. The currents are modified at a starting time, as determined by sensors.

Abstract: A printer or copier has an intermediate carrier for applying toner to the recording medium. Used toner is scraped off the intermediate carrier and carried away by a conveyor helix. The conveyor helix is of a spring wire and a resistance element is provided extending between coils of the conveyor helix to intermittently catch and release the spring wire so as to cause wobbling of the conveyor helix and prevent sticking of the used toner.

Abstract: An apparatus for turning and displacing a web of continuous recording material in a printer or copier provides that the web is conveyed along a transport path by a web supply, around a deflection device below the web supply, and to a web take-up that is spaced by at least one web width from the deflection device. The first edge of the web facing the take-up device lies loosely on a first guide surface of the deflection device. The web may also be displaced without turning.

Abstract: A pneumatic toner feed mechanism for a developer station of a printer or copier is disclosed. The feed mechanism includes at least two storage containers which are separately allocated to the developer chambers of the developer station. The toner storage containers act as intermediate storage units which are linked to the developer chambers of the developer station by supply ducts. Toner is supplied from bottle-shaped transport containers by a vacuum transport mechanism to the toner storage containers. The transport mechanism includes controllable solenoid valves. The toner level is detected by way of a control mechanism that preferably includes associated capacitive sensors. When a level of toner in a storage container exceeds a predetermined level, the associated valves are opened thereby eliminating the vacuum and associated automatic toner refill. A controller or control means may include a priority control system which preferably refills the toner of the main printing color.

Abstract: An electrographic printer with a printing unit that comprises a photoconductor provided with a toner image during the printing process and which further comprises a corona device arranged at a distance from the photoconductor that generates an electrical field during the printing process for transferring the toner image onto an endless carrier material is provided. The printer, in a first operating mode, can print a first web section of the endless carrier material conducted along a transport path and, in a second operating mode, can simultaneously print a second web section conducted along a parallel transport path and arranged next to the first web section at a distance therefrom. The length of the electrical field generated by the corona device is adjustable according to whether a first web section or a first and second web section is transported along the transport path.

Abstract: An apparatus is provided in a printer to prevent wrapping of the paper web onto the printer's fixing roller which fixes the toner particles onto the paper web. The apparatus includes a sensor to monitor the speed and moving direction of the web at the output of the fixing station. The sensor is connected to a controller which operates to halt the operation of the fixing station or the printer when the sensor senses a reversal of the moving direction of the web. The controller may average the web moving speed and compare the average speed to a predetermined speed for halting printer operation if the average speed traverses the predetermined speed.