Abstract: Apparatus for aligning a scanner assembly in a laser scanning unit for an image forming device. A MEMS torsion oscillator is attached to a spherical base that is received by a socket in a laser scanning unit. The pivotal center of the scanner coincides with the center of the spherical base such that the center of the scanner does not move as the scanner is aligned in the skew, process, and scan directions. In various embodiments, the aligned relationship of the spherical base to the socket is maintained by an adhesive, a through-bolt, or a plurality of spring-biased adjustment screws. The configuration and location of the adjustment screws is such that adjustment of the scanner assembly is accomplished without blocking the laser beam used for alignment.

Abstract: The white vector—the voltage difference between white areas of a latent image on a photoconductive unit and a developer roller—may be independently adjusted at each photoconductive unit, allowing multiple image forming units to be driven from a shared power supply. The photoconductive unit is charged to a high voltage level relative to the developer roller, and selectively optically discharged to the desired white vector by a first laser source. The voltage of the discharged area may be measured, or may be calculated by increasing the developer roller voltage a predetermined amount, discharging the photoconductive unit until toner is sensed in white image areas, and then reducing the developer roller voltage. The white areas are discharged using a different light source, such as a laser, LED or electroluminescent source. A second laser may be of a different wavelength than a writing laser.

Abstract: A scanning apparatus for a printer or similar instrument. A multiharmonic oscillator is used to provide a composite motion of a laser beam or other light beam to scan an imaging surface. The multiharmonic oscillator may have multiple sections each having a different resonant frequency. One section includes a reflector that intercepts the light beam, and drive electronics move the reflector so the light beam scans the imaging surface. Linear and complex non-linear motions of the light beam may be achieved. Microelectromechanical systems (MEMS) technology may be used to fabricate the oscillator.

Abstract: The white vector—the voltage difference between white areas of a latent image on a photoconductive unit and a developer roller—may be independently adjusted at each photoconductive unit, allowing multiple image forming units to be driven from a shared power supply. The photoconductive unit is charged to a high voltage level relative to the developer roller, and selectively optically discharged to the desired white vector. The voltage of the discharged area may be measured, or may be calculated by increasing the developer roller voltage a predetermined amount, discharging the photoconductive unit until toner is sensed in white image areas, and then reducing the developer roller voltage. The white areas may be discharged using a lower optical power from the writing light source or a different light source, such as a laser, LED or electroluminescent source. A second laser may be of a different wavelength than a writing laser.

Abstract: In bi-directional imaging, such as bi-directional printing, a driving mechanism scans a light beam through a scan path across an imaging window. A controller enables transmission of video data to a modulator when the light beam is positioned for imaging on the imaging window. Video data is transmitted to the modulator when the light beam is traveling in a forward direction or a reverse direction across the imaging window, whereby a modulated light beam is capable of producing an image when traveling in the forward or reverse directions. The controller adjusts scan durations or image rasterization rates to ensure that each scan is properly aligned with the prior and subsequent scan.

Abstract: A method for improving the operation of an electrophotographic printer. The method includes providing an electrophotographic printer containing a laser scanning unit. A torsion oscillator for the laser scanning unit is enclosed in closed compartment. The closed compartment includes side walls having first and second side wall edges, a bottom wall attached on the first side wall edges, and a cover attached adjacent to the second side wall edges. The closed compartment is sufficient to reduce stray air currents from adjacent the torsion oscillator thereby improving the operation of the electrophotographic printer.

Abstract: A laser scanning unit is provided. It comprises a housing; a scanning device; a pre-scan assembly generating a light beam and directing the light beam toward the scanning device; and a post-scan optical assembly receiving a scanning beam reflected from the scanning device and causing the beam to traverse a photoconductive member along a scan path. The post-scan optical assembly comprises a sensor for detecting the beam at a start-of-scan location and an end-of-scan location along the scan path.

Abstract: A collimation assembly for a multi-beamed laser scanner including a collimation housing mounted to a printhead housing of the laser scanner, and at least two adjustment brackets supported on the collimation housing and located adjacent to each other in a cross-scan direction. Each of the adjustment brackets includes a mount member and a laser light source is supported within each of the mount members, each of the light sources defining a respective light beam axis. At least two collimation lenses are also provided supported on the collimation housing and intersected by one of the light beam axes. Each of the adjustment brackets is movable relative to the collimation housing in a scan direction and in the cross-scan direction to locate each of the light beam axes at a predetermined position relative to a respective collimation lens.

Abstract: An optical scanning system including a resonant oscillating device having a first magnetic field and a mirrored surface. The system includes first and second light sources for directing first and second beams of light to the mirrored surface of the resonant oscillating device to provide first and second reflected scan beams. The second reflected scan beam is offset a first distance from the first reflected scan beam. A second magnetic field is included for interacting with the first magnetic field to provide torque to the resonant oscillating device for scanning the first and second reflected scan beams across a surface to provide first and second scan lines on the surface substantially simultaneously as the resonant oscillating device oscillates under the influence of the first and second magnetic fields. The optical scanning system is effective to increase scan efficiency of the resonant oscillating device over that of a system using a single light source.

Abstract: An optical apparatus compensates for imaging errors associated with the sinusoidal angular scan rate of a light beam reflected from a bidirectional scanning torsion oscillator. The compensation is achieved by a combination of pre-scan optics positioned between the source of the light beam and the scanning torsion oscillator, and post-scan optics positioned between the scanning torsion oscillator and an imaging surface of an imaging device. Based on the optical characteristics of its components, the post-scan optical system causes deflection of the light beam in the scan direction. To compensate for the sinusoidal scan rate, the deflection caused by the post-scan optical system is greater at the opposing edge positions of the imaging surface than at a central position. In this manner, the scan rate of the light beam at the first and second edge positions is substantially equivalent to the scan rate at the central position.

Abstract: A laser scanning unit is provided comprising a housing; a scanning assembly including a scanning device; a first light beam source directing a first light beam toward the scanning device; a second light beam source directing a second light beam toward the scanning device; and first and second post-scan optical assemblies located to receive first and second scanning beams reflected from the scanning device. Each post-scan optical assembly may comprise a first, second and third fold mirror, a first f-theta lens located between the first and the second fold mirrors, and a second f-theta lens located to receive light reflected from the third fold mirror and outputting a compensated scanning beam for generating a scan line on a corresponding photoconductive member.

Abstract: An image scanning apparatus and a torsion oscillator are capable of operating across a dynamic range of possible operating frequencies. The image scanning apparatus uses a light source to produce a light beam, and the oscillator scans the light beam through a scanning pattern. The oscillator includes a plate member having a non-rectangular shape. At least one magnet is disposed on the plate. A surface of the plate member includes a reflective surface for reflecting a light beam. A frame is disposed in a spaced apart relation to a lower surface of the plate member. The frame includes at least one coil configured to induce an electromagnetic force on the at least one magnet to thereby oscillate the reflective surface to a rotational angle of oscillation at an oscillation frequency. The system also includes an imaging surface disposed in the path of the scanning pattern so that the light beam scans across the imaging surface, and a mechanical drive to move the imaging surface.

Abstract: An optical scanning system including a resonant oscillating device having a first magnetic field and a mirrored surface. The system includes first and second light sources for directing first and second beams of light to the mirrored surface of the resonant oscillating device to provide first and second reflected scan beams. The second reflected scan beam is offset a first distance from the first reflected scan beam. A second magnetic field is included for interacting with the first magnetic field to provide torque to the resonant oscillating device for scanning the first and second reflected scan beams across a surface to provide first and second scan lines on the surface substantially simultaneously as the resonant oscillating device oscillates under the influence of the first and second magnetic fields. The optical scanning system is effective to increase scan efficiency of the resonant oscillating device over that of a system using a single light source.

Abstract: A lens has a lens body (1), reinforcing extensions (3a, 3b) and a clear aperture (9) surrounded on top and bottom by lens body. The lens is suitable for spot scanning. The lens is made of a water absorbing material, such as most polymers, particularly acrylate polymers. Aluminum sheets as vapor barriers are attached on each side of the lens body. This results in excellent resistance to change or distortion in high humidity environments.

Abstract: A collimation assembly for use in a laser scanning unit is provided. Methods for aligning collimation and pre-scan assemblies in a laser scanning unit are further provided. Also provided are alignment structures for use in aligning collimation and pre-scan assemblies in a laser scanning unit.

Abstract: A collimation assembly for use in a laser scanning unit is provided. Methods for aligning collimation and pre-scan assemblies in a laser scanning unit are further provided. Also provided are alignment structures for use in aligning collimation and pre-scan assemblies in a laser scanning unit.

Abstract: A laser scanning unit is provided comprising a housing; a scanning assembly including a scanning device; a first light beam source directing a first light beam toward the scanning device; a second light beam source directing a second light beam toward the scanning device; and first and second post-scan optical assemblies located to receive first and second scanning beams reflected from the scanning device. Each post-scan optical assembly may comprise a first, second and third fold mirror, a first f-theta lens located between the first and the second fold mirrors, and a second f-theta lens located to receive light reflected from the third fold mirror and outputting a compensated scanning beam for generating a scan line on a corresponding photoconductive member.