Abstract: A multi-beam scanning device for focusing deflected light beams onto an object to be scanned includes a light source unit, a deflector, a pitch adjustment device, and a conical-shape compression-torsion coil spring. The light source unit is rotatable about an optical axis and includes a plurality of light sources to emit the light beams and a plurality of coupling lenses disposed corresponding to the light sources. The deflector deflects the light beams emitted from the plurality of the light sources and passed through the plurality of the coupling lenses. The pitch adjustment device moves the light source unit in a first direction around the optical axis to adjust a beam pitch. The conical-shape compression-torsion coil spring urges the light source unit in a second direction opposite the first direction around the optical axis as well as in the optical axis direction. An image forming apparatus includes the multi-beam scanning device.

Abstract: An optical scanning device 65 is adapted to bring a deflector mirror plane 651 into independent pivotal motions about a first axis and a second axis perpendicular to each other. A mirror driver section including a first axis driver and a second axis driver is so controlled as to bring the deflector mirror plane 651 into pivotal motion about the first axis thereby deflecting a light beam L for scanning along a main scan direction. On the other hand, the deflector mirror plane 651 is pivotally moved about the second axis thereby to adjust the scanned beam L for its position on a photosensitive member 2 with respect to a subscan direction. Thus, even if the scanned beam is deviated from a reference scan position with respect to the subscan direction due to component tolerances or assembly errors, such a deviation can be corrected.

Abstract: An image is formed by dividing rasterized original image data into regions in accordance with N recording heads, and scanning a recording body by simultaneously irradiating recording beams from the N recording heads. Corrected image data divided into regions in accordance with the recording heads are generated by changing the rasterized original image data based on information including positional displacements of the recording beams, so that the positional displacements are corrected. Scanning information is generated based on the positional displacement information. The scanning information includes positions and orders for the recording beams to scan the recording body to record the corrected image data.

Abstract: A multi-beam scanning device includes a light source part having a plurality of light emitting sources which light emitting sources are monolithically arranged in a surface perpendicular to an optical axis; a light deflection part configured to deflect a plurality of light beams from the light source part in a lump and scan an image carrier surface; and an image-formation optical system where lateral magnification is set so that beam spots of the plural light beams are arranged at a designated pitch in a sub-scanning direction on the image carrier surface.

Abstract: Positioning displacement characteristics of each of scanning beams are obtained in advance. The positioning displacement characteristics is indicative of a relation between temperature and a displacement amount by which each of the scanning beams is displaced in a sub-scanning direction. A displacement control is performed based on the positioning displacement characteristics by shifting the positioning displacement characteristics in a direction opposite to that of a trend of the positioning displacement characteristics within a pixel pitch.

Abstract: An image forming apparatus that is operable at a plurality of image forming speeds and can be constructed at low costs without adding circuits or the like. A conversion circuit converts image data into lighting patterns for turning on/off laser light on a basis of each of units of auxiliary pixels formed by dividing a pixel as an image forming element. A shift register sequentially stores lighting patterns for pixels pixel from the conversion circuit, and sequentially outputs them to a laser drive circuit. In monochrome printing, the rotational speed of a polygon motor is set to perform a printing operation. In color printing, the difference between an image forming speed for the monochrome printing and an image forming speed for the color printing is calculated, and based on the difference, the amount of insertion of pixel pieces using the shift register is determined for a printing operation.

Abstract: An image forming apparatus is provided with a light scanning device that directs laser beams emitted from a plurality of laser light sources on to a plurality of photoconductive members via focusing device which includes optical elements and a deflecting device that deflects the beams in a main scanning direction; an image forming device which forms visible images of different colors from images written onto the photoconductive members by the light scanning device; and an intermediate transfer member or a recording sheet transport member capable of carrying the visible images formed on the photoconductive members. When in detection mode, a control device controls the correction of color registration errors between each color forms patterns on an intermediate belt by an image forming device, detects the patterns by a color registration error detection sensor, and stores the color registration error correction values obtained from the detection output of the sensor in a memory device.

Abstract: Adaptive correction techniques are disclosed that adaptively correct aberrations which may arise in systems such as laser printers, for example. For laser printers, calibration data processing results may be detected by a detector that is disposed to correspond physically to the recording medium so that characteristics such as position and intensity of a laser beam at the detector corresponds to that of a laser beam at the recording medium. In this way, aberrations in system performance may be adaptively corrected while the system is performing operational processes.

Abstract: Laser printers are plagued with an assortment of alignment issues. In color laser printers the issues are exacerbated. Variations in distance from the mirror to the drum can lines in different color planes to vary in size. Variations in angles in the facets of the mirror can cause alignment issues between lines. Even lack of synchronization between the dot clock and start of line indication can cause misalignment between rows. In addition, a cosine distortion occurs due to the non-constant linear velocity of the laser scan of a single line. A very high speed master clock can drive the laser scanning unit. By using a very high speed clock, the control circuitry has the resolution to compensate for many of these distortion types, by appropriately counting clock cycles and indicating such to the laser modulator.

Abstract: An optical scanning apparatus forms a latent image by scanning a laser beam emitted from a light source on an image bearing member. The apparatus includes first and second laser beam detectors for detecting the laser beam and a scanning-line slope detector for detecting a slope of a scanning line on the image bearing member on the basis of the result of detection obtained by the first and second laser beam detectors. The first laser beam detector detects the laser beam in a scanning area in front of an area in which the latent image is formed on the image bearing member and the second laser beam detector detects the laser beam in a scanning area behind the area in which the latent image is formed on the image bearing member.

Abstract: An image forming apparatus includes a photoreceptor member; a LED head that includes a plurality of light emitting diodes arrayed in a line along a rotating axial direction of said photoreceptor member and that is modulated in response to image signals, so as to expose said photoreceptor member while said photoreceptor member is rotating; a deviation detecting sensor to detect deviations on a circumferential surface of said photoreceptor member; a filter to extract low frequency components including a rotational frequency component of said photoreceptor member from deviation signals detected by said deviation detecting sensor, so as to acquire deviation information with respect to said circumferential surface of said photoreceptor member; a driving section to move said LED head back and forth against said circumferential surface of said photoreceptor member; and a position controlling section to control said driving section, based on said deviation information acquired by said filter, so as to keep a distance

Abstract: An image recording apparatus according to this invention includes a frequency divider 22 for generating a reference signal of a frequency higher than that of a dot clock signal, a pulse exposure control circuit 31 for causing a laser beam emitted from a laser diode 27 to irradiate a recording medium when both an image signal and the reference signal are ON, and a switching device 25 for switching between a first recording mode for causing the laser beam emitted from the laser diode 27 to irradiate the recording medium when the image signal is ON, and a second recording mode for causing the laser beam emitted from the laser diode 27 to irradiate the recording medium when both the image signal and reference signal are ON.

Abstract: The invention relates to a method and apparatus for recording digital data on an image-receiving medium (20). The recording head (71) is transported along a slow-scan-direction (Y) and digital image data is recorded along a fast-scan-direction (X). The recording head (71) is decoupled from its drive (60) during recording of digital image data of a line or an image or part of it. The transient movement of the recording head (71) along the fast-scan-direction (X) is detected before and/or during exposure using a sensor system (52, 53) and these signals are used to derive a high precision synchronized clock by suitable interpolation and/or extrapolation for the recording of image data to the image-receiving medium (20).

Abstract: An image-recording device for generating image spots (210) by n individually controllable light sources (12), which each have a distance si, i being=1 . . . n, to an object line (14), in a projection line (16) of the object line (14) on a printing form (28), which moves with a velocity component v normally to the direction defined by the projection line (16) and tangentially to the surface of the printing form. The image-recording device is distinguished by the triggering device (216) having an assigned time-delay device (222), which delays the tripping instant of the triggering device for each light source (12) as a function of the particular distance si. The image-recording device may advantageously by used in direct imaging print units or printing-form exposure units.

Abstract: An image forming device includes a photoconductor drum having a rotational shaft in a first direction, and an exposure head having a plurality of imaging optical systems disposed in the first direction and a second direction and each having a negative optical magnification, and a light emitting element substrate on which a plurality of light emitting elements are disposed, the plurality of light emitting elements emitting light beams imaged on the photoconductor drum by one of the imaging optical systems, and the light beams are imaged by the imaging optical systems disposed in the second direction on the photoconductive drum at positions different from each other in the second direction.

Abstract: A high-quality image forming apparatus that is capable of accurately adjusting the size and position of an image during image formation on a second surface of a transfer material, even when there has been expansion/contraction of the transfer material due to thermal fixing after image formation on a first surface thereof, to thereby avoid image displacement during two-sided image formation and multiple image formation.

Abstract: An LED printer has a photosensitive drum, a resist roller for feeding a printing medium to the photosensitive drum at a first constant speed, a fixing device for discharging the printing medium from the photosensitive drum at a second constant speed, a separation type LED head arranged zigzag, and a printing control circuit for detecting a position of the printing medium fed by the resist roller or the fixing device and adjusting printing timings of the first portion LED head and the second portion LED head based on the detected position and the LED head interval. The LED printer can normally correct a print length in each of a front end region and a rear end region of a sheet.

Abstract: A line head, includes: a microlens array in which a plurality of microlenses having a magnification whose absolute value is below 1 are arranged in a main scanning direction of a surface-to-be-scanned, and a plurality of luminous element groups which are arranged in a one-to-one correspondence with the respective plurality of microlenses, wherein in each of the plurality of luminous element groups, a plurality of luminous elements are arranged at mutually different main-scanning-direction positions in the main scanning direction, the plurality of luminous elements are respectively caused to emit lights at timings in conformity with a movement of the surface-to-be-scanned in a sub scanning direction, and light beams emitted from the plurality of luminous elements are imaged on the surface-to-be-scanned at mutually different main-scanning-direction positions in the main scanning direction to form a plurality of spots side by side on the surface-to-be-scanned in the main scanning direction, and in each of the pl

Abstract: A method of printing using an image-on-image device that includes a photoreceptor, including monochrome exposing the photoreceptor or monochrome charging the photoreceptor, wherein monochrome exposing the photoreceptor includes charging the photoreceptor, successively exposing the photoreceptor in a monochrome mode using a plurality of exposing devices during a single revolution of the photoreceptor relative to the exposing devices, and developing a monochrome image on the photoreceptor; and monochrome charging the photoreceptor includes successively charging the photoreceptor via a plurality of charging devices during a single revolution of the photoreceptor relative to the charging devices, exposing the photoreceptor using an exposing device, and developing an image on the photoreceptor. A marking device capable of implementing the method of printing.

Abstract: A deviation amount detecting device for use in an electrophotographic color image forming device is configured to correct, during an inter-cycle period in which computation of a first deviation amount using a result of reading of deviation detection patterns is held in a waiting state, a second deviation amount computed using a result of measurement of a scanning time of a light beam, based on a first deviation amount computed at a latest cycle, so that a corrected amount of deviation of a main scanning direction and a corrected amount of deviation of a sub-scanning direction are computed.

Abstract: An optical scanning characteristic control method is applied to an optical scanning system in which a beam is deflected, and the deflected beam is converged and directed toward a scanning surface, so that optical scanning of the scanning surface is performed by an optical spot formed thereon by the deflected beam. The method comprising the steps of a) disposing a beam deflection control device on the light path of the beam before it is incident on the scanning surface; and b) controlling a beam deflection amount of the beam deflecting device provide to an incident beam so as to control a scanning characteristic of the optical scanning.

Abstract: An image forming apparatus includes an image forming unit that forms a color image in which a plurality of color component images are superimposed; and a formation controlling unit that allows the image forming unit to form images for adjustment of formation positions of the respective color component images. The formation controlling unit allows the image forming unit to form, for each color, a plurality of adjustment images having different tilts with respect to a main scanning direction. A shift of a detected position of each adjustment image from a reference position in which each adjustment image should be formed is calculated, a tilt and an intercept of a regression line that uses the reference positions and the calculated shifts as variables are calculated, and a shift in the main scanning direction and a shift in a sub-scanning direction are determined based on the calculated tilt and intercept.

Abstract: An image forming apparatus and method that detects a light beam deflected by a polygon mirror at least at two separate locations on the line in the horizontal scanning direction, measures the difference in time of passage between these locations, makes a comparison between the thus determined interval and a reference interval, and generates a proper amount of correction corresponding to the determined interval, such as either correction data adapted to change the frequency of a pixel clock, or further correction data to change the period of the pixel clock by pixels.

Abstract: An imaging system is equipped with two or more exposure heads that are each able to image either a separate media sheet or a portion of a single media sheet loaded on a media carrier. The imaging time for any combination of media sheets is minimized by providing for the adjustment of the spacing between the dual exposure heads whenever the media configuration changes. In imaging a unitary image using two exposure heads to each image a sub-image, any discontinuity between the end of the first sub-image and the start of the next sub-image is reduced by changing the traversing speed of one of the exposure heads by a fractional amount.

Abstract: Methods are provided for imaging patterns on a media. The steps of the method include operating a first imaging head with individually addressable channels to direct imaging beams to form a first image on the media while scanning over the media along a scan path. A second imaging head with individually addressable channels is operated, either at the same time or a different time, to direct imaging beams to form a second image on the media while scanning over the media along a second scan path. It is possible that the first scan path may or may not be parallel to the second scan path, and that the first image may or may not be aligned with the second image. The first image may or may not be skewed with respect to the second image.

Abstract: An apparatus includes: a latent image carrier which is freely rotatable in a predetermined sub scanning direction; a latent image carrier gear which is attached to an end portion of the latent image carrier; a drive motor which applies drive rotation force upon the latent image carrier via the latent image carrier gear and which rotates the latent image carrier; a line head which forms on the latent image carrier a line latent image which extends in a main scanning direction which is approximately orthogonal to the sub scanning direction; an exposure controller which provides an image signal to the line head and controls writing of the line latent image; a phase detector which detects the phase data regarding the latent image carrier gear; and a timing controller which adjusts the write location of the line latent image on the latent image carrier based on the phase data detected by the phase detector.

Abstract: A technique can define a right position for forming a toner image on the transfer surface of an intermediate transfer body regardless of the size and the number of the sheets on which toner images are to be transferred. An image forming apparatus for forming a toner image on the transfer surface of an intermediate transfer body by correcting the position for forming the toner image comprises a data acquisition section that acquires predetermined data relating to the printing data for forming an image on a sheet and a correction section that corrects the predefined value for defining the position for forming the toner image on the transfer surface according to a predetermined correction value corresponding to the predetermined data acquired in the data acquisition section.

Abstract: The invention describes a method and system for correcting linearity error of an electrophotographic device with a reduced number of lenses. The method and system insert additional time-slices in the data being processed by the electrophotographic device. The additional time-slices are inserted in the data in a predefined order based on a plurality of random numbers. The insertion of additional time-slices corrects the linearity error of the electrophotographic device.

Abstract: A lateral position of a photoreceptor belt is detected by at least a first sensor and a second sensor, respectively located near a first imager and a second imager. The detected lateral positions of the photoreceptor belt by the first sensor is compared to the detected lateral position of the photoreceptor belt by the second sensor. Based on this compared difference, a correction is applied to the position of the second imager relative to the photoreceptor belt. To apply the correction, the location of the start of scan (SOS) of the respective imagers is moved.

Abstract: A multi-beam image forming apparatus and a method using the same. The image forming apparatus includes: an image process module to divide first image data into a plurality of second image data; a light scanning unit to scan the plurality of second image data using a plurality of laser beams; and a controller to control the formation of an electrostatic latent image of the first image data on a photosensitive body in an overlapping manner, using at least two of the plurality of laser beams.

Abstract: Exemplary embodiments provide an apparatus, method, system, computer program and product, each capable of controlling a timing for starting image formation such that when forming a preceding image and a following image, a timing for starting formation of the following image is adjusted based on a timing for starting the preceding image.

Abstract: An optical scanning device 65 is adapted to bring a deflector mirror plane 651 into independent pivotal motions about a first axis and a second axis perpendicular to each other. A mirror driver section including a first axis driver and a second axis driver is so controlled as to bring the deflector mirror plane 651 into pivotal motion about the first axis thereby deflecting a light beam L for scanning along a main scan direction. On the other hand, the deflector mirror plane 651 is pivotally moved about the second axis thereby to adjust the scanned beam L for its position on a photosensitive member 2 with respect to a subscan direction. Thus, even if the scanned beam is deviated from a reference scan position with respect to the subscan direction due to component tolerances or assembly errors, such a deviation can be corrected.

Abstract: A laser beam scanning device is disclosed. The laser beam scanning device includes a diffraction optical element which forms a pattern of a diffraction image including two images extending in a direction corresponding to the sub scanning direction and one image extending in a direction inclined by ? (0<?<90°) from the direction corresponding to the sub scanning direction by inputting a laser beam which is led to a surface of a photoconductor drum, and a light receiving element which receives the pattern of the diffraction image.

Abstract: A color image forming apparatus of a so-called tandem type which has image forming units in correspondence with colors is provided. In the color image forming apparatus, a color discrepancy amount storage unit stores information of a color discrepancy amount of each of the image forming units, which is measured in advance. A first color discrepancy correcting unit performs color discrepancy correction in a pixel unit by performing coordinate conversion of bitmap data to be printed based on the information of the color discrepancy amount stored in the color discrepancy amount storage unit. A second color discrepancy correcting unit performs color discrepancy correction in less than a pixel unit by performing tone correction of the bitmap data corrected by the first color discrepancy correcting unit based on the information of the color discrepancy amount stored in the color discrepancy amount storage unit.

Abstract: A write controlling device for an image forming apparatus including a time lag detecting device configured (i) to detect a time lag between (a) synchronization signal generated by a synchronization detecting device and (b) a mark signal generated by a mark sensor configured to detect a mark on a transfer belt configured to transfer plural color toner components; and (ii) to output a white line insertion value using the detected time lag; and a reconfiguration device configured to reconfigure the white line insertion value and a write timing setting value defining a writing start position in a sub-scanning direction using a write timing ancillary value which defines the quantity of reconfiguration.

Abstract: An image forming apparatus forms a latent image on a photoconductive member by scanning a light beam with a rotational deflector, and forms a visual image on a sheet without temporarily stopping the sheet on a sheet conveyance path. The image forming apparatus includes a motor that drives the rotation deflector when an image formation instruction is given, a rotation status-determining device that determines if the motor driven the rotation deflector reaches steady state, and a sheet feed control device that starts conveying the sheet (from a starting position of the sheet conveyance path) when the rotation status-determining device determines that the motor reaches the steady state. A detection device detects a passage time when the sheet passes a prescribed position on the sheet conveyance path. A latent image formation control device starts forming a latent image on the photoconductive member based on the passage time.

Abstract: An image forming apparatus includes a light source that emits a light beam in a main scanning direction according to image data to be used for image formation, a control unit that controls the light source, and detectors that detect the light beam. The main scanning direction is divided into areas and a cycle of a pixel clock is corrected in each area independently based on detection results of the detectors so as to correct an image position and image magnification.

Abstract: An optical scanner can write a full-color image without occurrence of writing position differences even if a record density is switched. The optical scanner includes a black writing illuminant for optically writing an image at a plurality of record densities and a color writing illuminant for optically writing the image at a predetermined record density. The optical scanner adjusts a resist position for a full-color image with respect to the main and sub-scanning directions by switching a writing position of the black writing illuminant in accordance with a requested record density and then writes the full-color image at that writing position.

Abstract: A method for forming a pixel (20) having a predetermined density onto a sensitized recording medium moving in a length direction energizes a pixel exposure source (14) to begin exposure at the leading edge (34) of a pixel (20) and for a first predetermined time interval. The pixel exposure source (14) is de-energized for a period depending on the predetermined density and on media transport speed, then re-energized at the termination of the period. The pixel exposure source (14) is then de-energized at the end of a second predetermined time interval to terminate exposure at the trailing edge (36) of the pixel (20), whereby spatial dimensions of each pixel (20) are maintained at variable transport speed or density of pixel (20).

Abstract: An image forming apparatus capable of decreasing the image unevenness of a superimposed image at the time of forming starting (head) lines of the images in respective colors with different beams in order to decrease a shift of a superimposed image. Let a position, where an image in a first color is formed with a beam A as a leading beam, be (a). Let a starting position of formation of an image in a second color be (b), and one dot (line) of shift arises in the superimposed image. In order to decrease the shift of the superimposed image, image formation is performed with selecting a beam B as a beam which writes a head of the image (c). When image formation is performed for color shift reduction with changing a leading beam for each color image, tonality correction is performed to each beam for subsequent images so as to decrease image unevenness due to the difference between shapes and exposure power of respective beams.

Abstract: When images are to be printed on two, front and lower surfaces of a sheet, in order to register the position of the image on the front surface and the position of the image on the back surface highly accurately, an image printing apparatus of this invention includes an image printing section which forms the image for the front surface of the sheet as well as an image of a reference mark on a photosensitive member at one portion in a region outside an image printing region and transfers the images onto the front surface of the sheet, a fixing unit which fixes the transferred images on the sheet, a line sensor which detects the reference mark after fixing printed on the front surface of the sheet, an arithmetic operating section which obtains a shrinkage factor of the sheet on the basis of a size of the reference mark before fixing and a size of the detected reference mark after fixing and calculates a position and magnification of the image to be printed on the back surface on the basis of the shrinkage factor

Abstract: The exposure apparatus is provided with: plural light emitting elements that are arranged in a line; a substrate that the plural light emitting elements are arranged thereon; plural temperature measuring units that are arranged along the arrangement direction of the plural light emitting elements and measure temperatures of the substrate on which the plural light emitting elements are arranged; and plural heating units that are arranged along the arrangement direction of the plural light emitting elements and heat the substrate on the basis of the temperatures measured by the temperature measuring units respectively.

Abstract: Reflex writing is a group of algorithms developed to maintain color registration in xerographic systems using multiple imagers, in which sequential color separations are written based on events in the spatial domain. The imaging system includes a raster output scanner imager for the black station and a light emitting diode bar for the color station. A simulated machine clock signal is generated based on a running average of a plurality of actual machine clock periods determined from pulses received from a photoreceptor module drive roll encoder. For each black scanline written the distance the belt travels is tracked using the simulated machine clock signal, and when the black latent image scanline has traveled the known distance between the two imagers, the light emitting diode scanline is written registered with respect to the raster output scanner scanline.

Abstract: The positioning of image data written along a laser beam scan path in the scan direction, e.g., the margin and/or line length is adjusted in a manner that compensates for changes in the laser beam scan path as a result of one or more operating conditions, such as changes in temperature. Further, the positioning of image data in the process direction may be adjusted in a manner that compensates for changes in the laser beam scan path as a result of the one or more operating conditions.

Abstract: A system and method are provided for calibrating a beam array of a printer. The method includes the operation of printing a dot pattern using the beam array of the printer. The dot pattern can then be scanned into an electronic file using an optical scanner. Another operation is calculating distance calibration errors found in the dot pattern in the electronic file using a software module applied to the electronic file.

Abstract: An apparatus includes: a latent image carrier which is freely rotatable in a predetermined sub scanning direction; a latent image carrier gear which is attached to an end portion of the latent image carrier; a drive motor which applies drive rotation force upon the latent image carrier via the latent image carrier gear and which rotates the latent image carrier; a line head which forms on the latent image carrier a line latent image which extends in a main scanning direction which is approximately orthogonal to the sub scanning direction; an exposure controller which provides an image signal to the line head and controls writing of the line latent image; a phase detector which detects the phase data regarding the latent image carrier gear; and a timing controller which adjusts the write location of the line latent image on the latent image carrier based on the phase data detected by the phase detector.

Abstract: A method and a device adapt the number of stepping motor cycles K to a temperature-dependent length change of a feed spindle in an exposer for recording printing originals. The length change is measured via a reference rod, which is disposed parallel to the feed direction of the exposure head carrier. A reference distance is disposed on the reference rod. The exposure head carrier is located on a feed spindle, which is driven by a stepping motor. A number K0 of cycles of the stepping motor per revolution of the exposure drum for a specific printing result is determined once. A corrected number Kk of stepping motor cycles for achieving the same printed result is then determined as a function of the different temperature-dependent length changes of feed spindle and reference rod.

Abstract: A method of, and apparatus for, reducing the visibility of banding artifacts on a printed medium comprising producing synthetic artifacts on the printed medium, overlapping scan lines at swath boundaries and controlling exposure along a scan line to reduce the visibility of the banding artifacts.

Abstract: An image-forming apparatus and print media recognition method therefor, wherein the apparatus comprises a first light-emitting element for emitting light to a print medium at a predetermined first incident angle, a second light-emitting element for emitting light to the print medium at a predetermined second incident angle, and a light-receiving element installed along an optical axis of total reflection light emitted from the first light-emitting element and reflected from a surface of the print medium. The apparatus further comprises a control unit for controlling the first and second light-emitting elements to alternately emit light for deciding a print medium material based on a reflection amount of light received by the light-receiving element and establishing print conditions adapted to the print media.

Abstract: An imager comprising a photosensitive surface; a light source which produces at least one scanning light beam; a deflector, arranged to deflect the at least one scanning light beam onto the photosensitive surface; and a sensor which measures the orientation of the deflector. The imager also comprises a controller operative to determine a placement error of said at least one scanning beam on the photosensitive surface, responsive to the orientation measurement by the sensor: and an actuator, responsive to the displacement error, and arranged to change the direction of deflection of the at least one light beam by the deflector. The sensor is configured to measure the orientation of the deflector substantially at a null in a vibrational mode of the deflector.