Abstract: A method and apparatus for using a raster output scanner which includes an array of independently addressable light valve elements that control the slow scan direction position of a spot in an image plane. In operation, the array is illuminated by light from a separate optical source and disposed such that the spot from each element of the array impinges the image plane in a different position in the slow scan direction and such that the maximum distance between the spots is less than the distance between scan lines. Only a single element of the array passes light per scan line, thus only a single spot is formed on the image plane per scan line. Control of which element in the array transmits a light beam per scan line allows control of the spot position in the slow scan direction for that scan line.

Abstract: A print apparatus includes a photoconductor and a mechanical system for moving the photoconductor past a scan line exposure station. The print apparatus includes a test signal generator for providing outputs indicative of the movement of the photoconductor. A first comparator produces a first position error signal that is derived from a difference between a reference signal and a position error signal output, such position error signal indicating that the position of the photoconductor differs from a predetermined print position that is determinable with respect to the reference signal. The print apparatus further includes a laser beam scanner and a beam detector for producing a scan position signal. A second comparator is responsive to the scan position signal and the position error signal from the first comparator to produce a beam deflection control signal that is applied to a beam deflector.

Abstract: Fluorescent reference tracks for use in correcting for geometric and other distortions in an image scanning system comprising a rotatable cylindrical drum assembly and an optical subsystem disposed within a protective housing is disclosed. Fluorescent reference tracks illuminable by light outside the visible spectrum, such as ultraviolet (UV) light, are disposed on inner surfaces of inwardly directed film support shoulders of the drum assembly. Respective edges of film containing an image to be scanned are retained on the outer surfaces of the film support shoulders of the drum assembly. As the film is rotated by the drum assembly past a primary light source disposed adjacent one side of the drum, light from the primary light source is directed through the film and is focused by a lens assembly disposed internal to the drum assembly onto a sensor assembly disposed at an opposite side of the drum assembly, which scans the transilluminated film portion.

Abstract: A system and method of correcting aberrations in an output image of an image transfer apparatus, the aberrations being due to variations in a velocity of a scanning surface in the image transfer apparatus. Specifically, laser printer banding effects are reduced by modifying the gray scale dithering concentration based on a sensed variation of drum rotation velocity. A closed loop feedback system monitors errors in the drum motion and compensates the modulation of the laser to help cancel out the perceivable amount of banding effect in the printed image.

Abstract: A laser beam printing device for conducting the print includes a control circuit for controlling a rotation speed of a rotation mirror which reflects the laser beam to scan, an image processing circuit for outputting image information in synchronism with an origin pulse signal, and an origin sensor to receive the laser beam to generate a detection signal and to transmit the signal to the image processing circuit as the origin pulse signal. The control circuit receives the detection signal from the origin sensor as a signal for detecting the rotation speed of the rotation mirror.

Abstract: A device for patterning an imaging member (46) is provided. The device comprises a light source (24) which emits light rays (26). Light rays (26) pass through a collimator lens (28) to collimate the light rays (30). The light then strikes a spatial light modulator (32) which is controlled by a computer (40) to reflect the light (42). The light passes through an imaging lens (44) to magnify the pattern for striking imaging member (46). Imaging member (46) is thus patterned by changing modulator (32) by computer (40).

Abstract: An image forming apparatus has an image scanner, a sensor for determining that the image sensor has scanned the front edge of a document, and a controller using main scanning line synchronizing signals and an output signal of the sensor as reference signals. In response to the reference signals, the controller causes at least a writing unit to start writing each image data of particular color and causes a transfer medium driving circuit to start driving a transfer medium. The apparatus allows image components of different colors to be transferred to the transfer medium one above the other in accurate registration.

Abstract: An image forming apparatus includes a device for forming an image; a device for detecting information relating to the image formed by the image forming device and for repeating the detection; and a device for determining a timing at which the detection is repeated by the detecting device on the basis of the information detected by the detecting device. A device for generating a pattern signal corresponding to a predetermined pattern for detecting the amount of registration deviation by the detecting device is also provided. In addition, a transport belt for transporting the recording medium through the plurality of image forming units is provided so that the image forming units also form predetermined images on the transport belt. A device is also provided for mechanically and/or electrically correcting registration in the image forming units on the basis of the amount of registration deviation detected by the detecting device.

Abstract: An image forming apparatus includes a charging member in contact with a photosensitive member for applying a charging voltage at least containing an a.c. component, a laser beam irradiator having a polygon mirror to form an electrostatic latent image and a developing unit for developing the latent image into a visible image and collecting residual developer remaining on the surface of the photosensitive member after the visual image is transferred to a transfer material. The number of revolutions Fp(rps) of the irradiator polygon mirror, the frequency Fb(Hz) of the a.c. component to be applied to the contact charging unit and the system velocity Vp(cm/sec) have a correlation so determined as to meet the requirement of:.vertline.Fp-2.times.Fb.vertline.<Vp or .vertline.Fp-2.times.Fb.vertline.>Fp/2.

Abstract: In a method and apparatus for raster scanning optical output device, such as a laser printer or the like, an array of independently addressable light emitting devices, such as an array of solid state lasers, is used to control spot position on an image plane in the slow scan direction. The array is disposed such that the spots emitted from each element of the array impinge the image plane displaced in the slow scan direction from one another. The total distance between all the spots is less than the distance between fast scan direction scan lines. Only a single element of the array is operated per scan line, thus only a single spot is formed on the image plane per scan line. Control of which of the elements of the array emits a light beam per scan line allows control of the spot position in the slow scan direction for that scan line.

Abstract: An image forming apparatus for forming images by allowing a light beam to be scanned and exposed on a photosensitive body includes a single detecting device for detecting the light beam scanned and exposed onto the photosensitive body, a plurality of signal generating devices for generating a predetermined control signal on the basis of an output from the detecting device, and an output control device for controlling the routing of an optical signal output which is output from the detecting device to the objective signal generating device.

Abstract: An electro-optic imager, used for exposing photosensitive media, wherein a moving drum or mirror(s) are used to obtain a scanning action, and a plurality of scanning beams is preferably used. An encoder, preferably a radial optical ruling and two or more optical interrupters, is attached to a shaft connected to the moving drum or mirrors which cause the optical scanning action. The output from the interrupters is processed in circuitry which interpolates position, generating clocks much faster than the rate of signals received by the interrupters, and responding quickly to any speed changes which might occur.

Abstract: An image exposure apparatus for eliminating discrepancies between the positions in the main scanning direction desired to be exposed and actually exposed by a laser beam. This may be achieved by controlling the rotational speed of the polygon mirror based on accurate rotation information. A first and second beam detectors for detecting the scanning laser beam in the main scanning direction are positioned at either side of the region of a recording medium where an image is to be formed. These detectors output signals upon detecting the laser beam. The scanning speed in the main scanning direction is calculated based on these signals. Further, deviation in speed in the main scanning direction is obtained from these signals. Rotational speed and phase information obtained about the polygon mirror using a clock signal is added to scanning speed deviation to control rotational speed of the polygon mirror.

Abstract: Computer controlled numbering of consecutive business forms is provided for both computer controlled presses and in the form of a retrofit unit for conventional rotary presses. The retrofit unit includes a disk provided with radially oriented metallic strips of predetermined locations on the disk, and mounted on a suitable shaft of the press. The disk cooperates with a stationary transducer mounted, for example, on a stationary press wall to send signals to the control unit to fire the printer.

Abstract: A raster output scanner is capable of creating images at a wide range of selectable resolutions. A laser source for creating an image is modulated at a pixel clock rate. A clock command value is determined as a function of a value related to the pixel clock rate and a value related to a desired resolution in the fast-scan direction and a desired resolution in the slow-scan direction of an image to be created on the photosensitive surface. The pixel clock rate is controlled in response to the clock command value. A polygon command value is determined as a function of the value related to the pixel clock rate, a value related to a desired resolution in the fast-scan direction of an image to be created on the photosensitive surface, and a value related to a rotational velocity of the polygon mirror. The rotational velocity of the polygon mirror is controlled in response to the polygon command value.

Abstract: An image forming apparatus which forms on a recording paper a visible image in accordance with image data, the forming being performed by using an electrophotographic method, and the apparatus being able to reduce a total recording time spent for recording one page as compared to the present technology. The image forming apparatus comprises a processing unit, comprising a photosensitive drum on which a latent image is formed while the drum is being rotated at a predetermined rotational speed, for processing the image data so as to form the visible image, a conveying unit for conveying the recording paper to/from the processing unit, a driving unit for driving the photosensitive drum and the conveying unit, and a controlling unit for controlling the driving unit so that the rotational speed of the photosensitive drum is changed based on a length of the visible image being formed on said recording paper.

Abstract: In an LED head, a photosensitive drum is positioned with reference to an upper surface of a circuit board on which surface at least one light-emitting element is supported in order to accurately set the distance between the light-emitting element and a photosensitive drum. Further, clips and a spring are used to accurately set the distance between the light-emitting element and a lens and to simplify the process of production.

Abstract: In a color image forming apparatus, a latent image forming device selectively forms on a photoconductive element images respectively corresponding to images of particular colors and a position mark latent image representative of position information. A developing unit develops the latent images with developers of respective colors to thereby produce corresponding color images, and develops the position mark latent image to thereby produce a position mark. The color images are transferred to an intermediate transfer belt one above another and then transferred to a recording medium. The position mark is also transferred to the transfer belt to form a position information portion. A position information detecting device generates a detection signal on detecting the position information portion formed on the transfer belt. A starting device starts forming a latent image on the photoconductive element in response to the detection signal.

Abstract: A multicolor non-impact printer is described that includes a photoconductive image receiver. The receiver is uniformly charged with an electrostatic charge. The receiver is then imagewise exposed by a first electronic exposure source to create a first electrostatic image. A toner of a first color is applied to the receiver to create a first toner image of the first color. The receiver is then exposed by a second electronic exposure source to create a second electrostatic image in the same general area as the first toner image. A toner of a second color is applied to the receiver to create a second toner image which, with the first toner image, forms a multicolor toner image. An encoder roller is associated with each exposure source and rotates with movement of said receiver and generates encoder position pulses. In response to the encoder position pulses, an address is generated for input to the look-up table.

Abstract: The raster scanning system of the present invention includes a beam generator which generates a beam of radiant energy in response to a drive signal. The drive signal comprising a series of pulses. The raster scanning system further includes a polygon having an overfilled facet design in which a plurality of facets are at least partially positioned in the optical path of the beam of radiant energy regardless of the rotational position of the polygon. The polygon being adapted to scan a spot across a beam receiving surface. Additionally the raster scanning system includes spot size correcting means for maintaining a constant spot size of the scanned spot by modulating the pulse width of the drive signal provided to the beam generator.

Abstract: A color image forming apparatus forms a color image by superposing images of plural colors in plane-sequential manner. In the color image forming apparatus, the amount of aberration between the detection signal for the recording medium for the first color and the horizontal synchronization signal is measured by a counter, and the start timing of image formation of the second and subsequent colors is controlled by a delay device, according to the measured amount of aberration.

Abstract: An image forming apparatus includes a movable image bearing member; an image forming device for forming an image on the image bearing member; a transfer device for transferring an image from the image bearing member onto a recording material at a transfer position; a detector for detecting a recording material conveying passage from a recording material feeding station to the image transfer position; and a controller responsive to the detector to form blanks at a leading and trailing edges of the recording material by controlling image forming operation of the image forming device.

Abstract: An optical printer, suitable for use in printing upon a recording medium, includes a tubular compensator disposed between a print head and the recording medium. The print head directs an elongated exposing beam through the compensator to impinge upon the medium, and the beam effects a line exposure across the medium. A transport device introduces relative motion between the medium and the print head during a line exposure by the beam. The relative motion is perpendicular to the exposure line and introduces a smear to each exposure line as well as an overlap between exposure lines. The tubular compensator includes inner and outer cylindrical surfaces having centers of curvature displaced relative to each other resulting in a wedge-like cross-section to a wall of the tubular compensator. The wedge angle varies with rotation of the compensator to provide for a linear deflection of the beam during a line exposure by the beam, thereby offsetting the advancement of the medium during the line exposure.

Abstract: An image forming apparatus such as a laser beam printer or an ink-jet recording apparatus has a recording head which records an image on a recording medium in the direction of main scan in accordance with image signals. The recoding medium is moved relative to the recording head in a sub-scan direction substantially perpendicular to the direction of the main scan. A controller controls conditions of recording performed by the recording head so as to effect a correction of recording density unevenness cause by a variation of the relative speed of movements of parts of the apparatus.

Abstract: An oscillation detector circuit detects an oscillating condition of a resonant light deflector having a reflecting mirror, and applies an oscillating condition signal to a reference signal generator, which generates a reference signal. An auxiliary scanning feed motor for feeding a scanned medium in an auxiliary scanning direction is controlled by the reference signal to adjust the speed at which the scanned medium is fed in the auxiliary scanning direction, depending on the oscillating condition of the resonant light deflector.

Abstract: In a color image forming apparatus such as a color laser printer, misregistration of colors of an output image along a subscanning direction is minimized so as to prevent accumulation of color misregistrations in the output image. In the apparatus, a photosensitive drum motor and a transfer drum motor are driven by motors exclusively provided thereto. The apparatus includes a photosensitive drum motor controller and a transfer drum motor controller respectively provided for speed-controlling the photosensitive drum motor and the transfer drum motor. By these motor controllers, a phase difference between a frequency generator signal from the motor and a phase reference signal is checked. Even if the phase difference exceeds a predetermined range of phase, the motor controller controls the motor so that the phase difference quickly falls within the predetermined range of phase.