Abstract: A disclosed control device includes a first unit configured to generate image data of multiple images to be superposed one on the other to form a single image and transmit the image data. The second control unit transmits to the first control unit a horizontal sync reference signal for achieving synchronization of the images in a horizontal direction. Based on the horizontal sync reference signal, the first control unit transmits to the second control unit a transfer clock signal that indicates transmission timing of the image data and an effective area signal that indicates an effective area of the image data. The first control unit asserts the effective area signal for an effective-area-signal assertion period that occurs between two consecutive reference-signal assertion periods during which the horizontal sync reference signal is asserted.

Abstract: In an electrophotographic (EP) device, methods and apparatus include determining a delay of one or more sensors (hsync) to accurately know when to start the process of scanning latent images. In one aspect, the sensor includes a leading and trailing edge defined along a direction of laser beam scan travel. Determining the delay includes learning a position of a laser beam on the sensor at a time when a controller connected to the sensor receives a signal from the sensor indicating the sensor is being sufficiently impinged upon by the laser beam. It also includes learning a latest possible position of the laser beam along the direction of laser scan travel where the laser beam can be turned on and still have the sensor assert a signal indicating it has been sufficiently impinged upon by the laser beam. Bi-directionally scanning EP devices are also disclosed, including controllers, photoconductors, sensors, etc.

Abstract: An optical scanning apparatus capable of properly correcting a main scanning scale factor. Upstream and downstream laser-light detection sensors of the optical scanning apparatus each generate a signal when first or second light beam passes through each of slits formed in the sensors. Based on signals, a scanning time required for each light beam to scan between the sensors is measured. A correction coefficient is decided by a correction value calculation unit based on a difference between wavelengths of the first and second light beams, a scanning time difference is calculated by a comparison unit based on the correction coefficient and scanning times of the light beams, and the downstream laser-light detection sensor is rotated by a sensor rotation drive unit to make the scanning time difference zero, whereby the slits are made parallel to each other.

Abstract: An image forming apparatus, and a method of controlling same, the image forming apparatus including an image carrying body; a light exposing unit which emits a light toward the image carrying body according to a light exposing signal; a light sensor which is disposed to a side of the image carrying body to receive a part of the emitted light; and a control unit which detects a biased amount in a sub scanning direction of the emitted light of the light exposing unit based on a sensing result of the light sensor.

Abstract: An image forming apparatus forms a latent image on a photoconductor by irradiating light beams from a plurality of light sources onto the photoconductor. A detection unit detects a time difference between timings of start writing on the photoconductor by the light beams in a main scanning direction. A calculation unit calculates a shift of each of the light beams in a sub-scanning direction based on the time difference detected by the detection unit and a rotation speed of the photoconductor. A correction unit corrects irradiated positions on the photoconductor by the light beams in the sub-scanning direction based on the shift calculated by the calculation unit.

Abstract: An apparatus (100) and method (200) that determines beam delays in a printing device is disclosed. The apparatus can include a photosensitive surface (110) and a raster output scanner (120) optically coupled to the photosensitive surface, an integrated scan detector (130) configured to detect the beams from the raster output scanner and configured to produce a signal based on the beams detected from the raster output scanner, and a beam calibration controller (140) coupled to the integrated scan detector. The beam calibration controller can be configured to determine at least one beam delay between the first optical emitter and the at least one second optical emitter based on signals from the integrated scan detector and can also be configured to delay operation between the first optical emitter and the at least one second optical emitter based on the at least one beam delay.

Abstract: Systems and methods are provided for aligning a video clock with the raster output scanner start-of-scan signal in printing systems. A system and method is proposed to align the pixel clock to an asynchronous reference signal generated in the raster output scanner. The proposed system and method adjusts a phase for a static phase value while performing a dynamic phase shifting for the start-of-scan signal alignment.

Abstract: An optical scanner unit includes an LD unit, a polygon mirror deflecting a light beam, an optical scan system focusing the light beam from the polygon mirror on a photoconductive drum to form an electrostatic latent image, and a synchronous detector receiving a part of the light beam to detect a write start position on the photoconductive drum in main scan direction. The synchronous detector is fixed on a portion of a housing at predetermined angles in main and sub scan directions relative to an incidence angle of the light beam on the synchronous detector.

Abstract: A measuring section that measures the position shift in the main scanning direction of a plurality of light sources, a signal generating section that generates synchronized INDEX signals that in which the writing timing of the different light sources has been adjusted according to the position shifts, a signal generating section that generates the signals for driving the light sources based on the synchronized INDEX signals and image data, and a measuring section that detects the timing shift component in the main scanning direction included in the synchronized INDEX signal generated in the condition in which adjustments have been made according to the position shift, and further shift correction is carried out in the main scanning direction based on the timing shift component, for the synchronized INDEX signal which are adjusted and generated in accordance with the position shift of a plurality of light sources.

Abstract: A method for determining a location on an image bearing surface of an image printing system where a toner image is to be printed is provided. The method comprises generating a first signal from a detector that is configured to detect a reference mark on the image bearing surface, and a second signal from a clock system that counts incremental movements of the image bearing surface, determining a first value that correlates the first signal and the second signal, where the first value corresponds to a value of the second signal at a start of characterization of the image bearing surface, and determining a second value using the first value, where the second value provides the location on the image bearing surface where the toner image is to be printed.

Abstract: A mechanical galvanometer tilt control system includes two beam detection sensors that detect vertical displacement caused by the horizontal rotation of a galvanometer and the vertical rotation of a photoconductive drum. The galvanometer may be in communication with a mirror holder that holds a mirror. The mirror holder may be operable to horizontally rotate the mirror as the mirror reflects a light beam onto a photosensitive image forming surface of the photoconductive drum. The two beam detection sensors receive the reflected light beam as the galvanometer generates one or more forward-going and one or more reverse-going scanlines on the photosensitive image forming surface. The mechanical galvanometer tilt control system may further determine an amount of vertical correction required to correct for the vertical displacement caused by the rotation of the galvanometer and the rotation of the photoconductive drum.

Abstract: Systems and methods are provided for correcting color registration errors in a printing device comprising a plurality of print engines driven by a single pixel frequency clock. In some embodiments, the print engines can include a reference print engine and one or more non-reference print engines. An adjusted resolution may be computed for color data sent to each non-reference engine to offset color registration errors attributable to the non-reference engine. The adjusted resolution is computed using calibration information for the non-reference print engines relative to the reference engine, and resolution information for color data processed by the first reference engine. The resolution of color data processed by each non-reference print engine is adjusted according to the computed adjusted resolution for the non-reference engine and sent to the print engines for printing.

Abstract: Multiple images are combined where the images exhibit variations in illumination between one another. The images are of the same portion of an object, and each image is represented by a set of image data. A comparative data transform is applied to each set of image data, such that the transformed comparative image data isolates and preserves first variations in the illumination between the images but suppresses second differences in illumination between the images. At least one normalization transform is determined from the transformed comparative image data sets. When applied to at least one of the image data sets, the at least one normalization transform minimizes the variation in illumination between the image data sets. Each determined normalization transform is applied to the at least one of the image data sets. The normalized sets of image data are transformed to a single image of the portion of the object.

Abstract: A color image forming apparatus and a control method thereof to correct an error between scanning lines due to an alignment error between the laser scanning units corresponding with each color of the image forming apparatus on the basis of a difference of detection times between termination signals for each color when the scanning units output a horizontal synchronization signal and a termination signal to scan a line. A difference of termination times between termination detecting sensors may be used to variably set video clocks for each color, thus reducing the number of components required and reducing the signal processing load. A single sensor may be used to detect the synchronization and termination signals, thus further reducing manufacturing costs.

Abstract: An image compensating method. First, multiple scanning lines are used to scan a document and a longitudinal black and white pattern, in order to produce the actual gray level value for multiple pixels with respect to each of the scanning lines and the document, as well as a correctional gray level value for complete black and a correctional gray level value for complete white with respect to the longitudinal black and white pattern. Then, the compensational gray level value with respect to the actual gray level value for each of the pixels is obtained according to the correctional gray level value for complete black, the correctional gray level value for complete white, the theoretical gray level value for complete black, the theoretical gray level value for complete white, and the actual gray level value for each of the pixels. Then, the procedure is complete.

Abstract: Scanning beam systems in both pre-objective and post-objective designs for display, printing and other applications. Various servo feedback control mechanisms are described to control display imaging qualities on fluorescent screens that emit fluorescent light to form images or a target surface of a printing medium or other objects.

Abstract: An image reading apparatus in which cross-talk noise occurring between plural reading units is reduced, an image reading method and an image reading program are provided. There are included plural reading units that respectively operate at different timings, a noise calculation unit that acquires first read data as a result of reading of a first read object as the read object by the plural reading units, acquires an operation state of the plural reading units during the reading of the first read object, and calculates, based on the operation state and the first read data obtained in the operation state, noise information based on the operation state, and a noise removal unit that acquires second read data as a result of reading of a second read object as the read object different from the first read object by the plural reading units, and removes noise from the second read data based on the noise information calculated by the noise calculation unit.

Abstract: An image forming apparatus capable of forming a high-resolution image without complicating a circuit construction. A difference between a phase of an operation clock for a BD detection unit and a phase of an operation clock for an image processing unit is measured by a phase measurement unit of the image forming apparatus, and a timing of data delivery between the BD detection unit and the image processing unit is adjusted by a BD input timing adjuster based on a measurement result. A difference between the phase of the operation clock for the image processing unit and a phase of an operation clock for a laser drive unit is measured by the phase measurement unit, and a timing of data delivery between the image processing unit and the laser drive unit is adjusted by an image output timing adjuster based on a measurement result.

Abstract: A method for compensating misalignment errors associated with a laser beam in an electrophotographic (EP) device is disclosed. A first value and a second value of a time-of-flight of the laser beam are determined. The second value of the time-of-flight is associated with a current value of SOS time and EOS time of the laser beam. The second value of the time-of-flight of the laser beam is compared with the first value of the time-of-flight. A duty cycle of a fuser of the EP device is monitored. An average value of the duty cycle of the fuser for a predetermined time period is determined. One or more alignment conditions of the laser beam are adjusted based on at least one of the comparisons of the second value and the first value of the time-of-flight of the laser beam, and the determined average value of the duty cycle of the fuser.

Abstract: Methods and apparatus include aligning printing of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine. At least first and second scan lines formed in opposite directions define a calibration page for manufacturing, servicing or end-user operation. The page includes pluralities of objects with one formed from either the first or second scan lines, but not both, and another of the objects formed from the other of the first or second scan lines, but not both. In this manner, corrections can be implemented by simply observing misalignments between the objects. Printed calibration pages also include visually or mechanically read objects for implementing corrections. In this regard, calibrating devices external to the EP device are contemplated. Objects include lines, squares or other shapes and their arrangement on a page varies. Fiducials for macro-scale observations are also contemplated.

Abstract: The video data is parallel processed allowing for extremely fast video processing or a greatly reduced clock requirement for the video processing circuit. In operation, each video channel reads from main memory. This allows each video channel to track the laser directly. The Parallel video processor receives non-columnar pixel data, such as rows. The videoprocessor may support printers of any width without significantly increasing the size of the system.

Abstract: In an image-forming device includes an image-forming unit, a first conveying unit, a first changing unit, and a second changing unit. The image-forming unit includes a rotatable mirror, a light-emitting unit, a photosensitive drum, a developing unit, a transferring unit. An electrostatic latent image composed of a plurality of line electrostatic latent images extending in a main scanning direction over a first length is formed on the photosensitive drum. The first conveying unit conveys a recording medium to the transferring position in a sub-scanning direction orthogonal to the main scanning direction. The first changing unit changes a rotating speed of the rotatable mirror to change the first length. The second changing unit proportionally changes a conveying speed of the first conveying unit in accordance with the change of the rotating speed of the rotatable mirror.

Abstract: An image forming apparatus includes: a plurality of optical scanning parts that scan a photoconductor with light of plural colors to form an electrostatic latent image on the photoconductor based on print data; and a controller that, based on a first optical scanning part to which a horizontal synchronization signal is applied of the optical scanning parts, calculates an offset value for light-scan of a second optical scanning part of the optical scanning parts, and controls the optical scanning parts to scan the photoconductor with the light according to the calculated offset value.

Abstract: First delay mechanisms to delay a beam-detect signal by different lengths of time in synchronization with a first clock signal. The beam-detect signal is generated responsive to one or more beams being output towards a rotating polygonal mirror having facets and directed towards a sensor. One or more second delay mechanisms each correspond to one of the beams to delay a second clock signal, resulting in a beam-clock signal to align the beam over successive reflections by the facets. A mechanism determines a delay by which each second delay mechanism is to delay the second clock signal, based on the beam-detect signal as differently delayed by the first delay mechanisms.

Abstract: The laser beam output from each of the semiconductor lasers is applied to the same print dot, such as each of the print dots on a thermosensitive recording medium, in such a manner that the laser beams are superimposed on one another sequentially at the same time that each of the semiconductor lasers is moved in the main scanning direction.

Abstract: An image forming apparatus includes photosensitive drums including one for black, light source devices, a rotary polygonal mirror having deflecting surfaces with chamfers, input optical systems, imaging optical systems and a synchronism detecting system for detecting a synchronizing light beam for determining the timing for scanning each of the photosensitive drums in a main scan direction, wherein the synchronism detecting system detects a light beam for forming an image of a color different from the black, and wherein the timing as the synchronism detecting device obtains a synchronizing signal and the timing as a light beam from the input optical system, which is at the side where the synchronism detecting device is provided, is incident on the chamfer of the deflecting surface of the rotary polygonal mirror, are at least partly overlapping.

Abstract: A light scanning device is provided. The light scanning device includes: an oscillating mirror which oscillates rotationally and reflects a light beam to be scanned over a scanning range, the scanning range including a first scanning range and a second scanning range set across a center of the scanning range; a detection unit including a light receiving face, on which the light beam is incident, to detect the light beam; and first and second stationary mirrors which reflect the light beam reflected by the oscillating mirror to the first scanning range and the second scanning range, respectively, to be incident on the light receiving face, wherein an incident pattern of the light beam reflected by the first stationary mirror incident on the light receiving face is different from an incident pattern of the light beam reflected by the second stationary mirror incident on the light receiving face.

Abstract: A light scanning unit of an image forming apparatus to scan a light beam in forward and reverse directions, the light scanning unit including: a beam deflector to deflect the light beam, and to form forward direction and reverse direction scanning lines in an image section and first and second non-image sections respectively provided on opposite sides of the image section; a reflecting member to reflect a light beam inputted from the beam deflector; and a light detecting unit to receive a first light beam directly inputted from the beam deflector, and a second light beam inputted via the reflecting member, wherein the reflecting member includes a reflecting unit to reflect the inputted light beam to the light detecting unit, and a distinguishing unit to distinguish the reflected second light beam from the first light beam.

Abstract: A mechanical galvanometer tilt control system includes two beam detection sensors that detect vertical displacement caused by the horizontal rotation of a galvanometer and the vertical rotation of a photoconductive drum. The galvanometer may be in communication with a mirror holder that holds a mirror. The mirror holder may be operable to horizontally rotate the mirror as the mirror reflects a light beam onto a photosensitive image forming surface of the photoconductive drum. The two beam detection sensors receive the reflected light beam as the galvanometer generates one or more forward-going and one or more reverse-going scanlines on the photosensitive image forming surface. The mechanical galvanometer tilt control system may further determine an amount of vertical correction required to correct for the vertical displacement caused by the rotation of the galvanometer and the rotation of the photoconductive drum.

Abstract: A tandem type color image forming apparatus, which can continuously form color images each containing two or more colors, including: a signal creating section having, for each color, two or more image area setting counters for generating an image valid area signal to set a starting position and a width of an image formation area in a sub-scanning direction; and a control section for executing color image formation control on a predetermined face of paper, based on an image top signal for controlling writing of an image on an image carrier and the image valid area signal for each color, wherein the control section sets each of the outputs of the image area setting counters independently according to a preset image formation mode, and selects and controls one of the image area setting counters for each image formation of each color.

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: Each light detecting sensor, which is installed corresponding to each photoconductor drum, and to which the plurality of light beams passing through the scanning optical system are incident while moving in a main scanning direction includes a light-receiving device having a first light-receiving unit and a second light-receiving unit, which have different intervals from each other in the main scanning direction depending on a position of a sub-scanning direction, all the sizes of the first and the second light-receiving units being sizes covering an overall virtual area in a quadrangular shape surrounding a plurality of light spots in the light-receiving surface.

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: A multi-beam optical scanning apparatus including a light source including a plurality of radiation points disposed spaced from each other in a main scanning direction and in a sub-scanning direction, a rotational polygon minor for deflecting a plurality of light beams radiated from the radiation points, and an imaging optical system for imaging the plurality of light beams deflected by a deflecting facet of the rotational polygon mirror. The deflecting facet has a width in which a light beam reaching a farthest location from a center of the deflecting facet is eclipsed by an edge of the deflecting facet if emitted prior to a light beam from a second radiation point when controlled by auto-power-control. Control is performed such that the light beam from the second radiation point is radiated prior to the light beam from the first radiation point when controlled by the auto-power-control.

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: In an image forming apparatus, a polygon mirror, a plurality of laser generators, a first sensor, and a second sensor are disposed at a resin frame. A laser beam outputted from each of the laser generators and deflected by a deflection surface is irradiated onto a surface of a photosensitive drum to scan the surface over a scan part. The first sensor is disposed at a first position to detect a laser beam deflected by the deflection surface. The second sensor is disposed at a second position to detect a laser beam deflected by the deflection surface. A storage unit stores correspondence information indicating shift of the scan part from a reference scan part in relation to time difference between detections of the laser beam by the first and second sensor. A controller controls the laser generator to output a laser beam based on the shift of the scan part.

Abstract: In a bi-directionally scanning electrophotographic (EP) device, methods and apparatus include storing alignment information. In one aspect, pre-characterization parameters of the EP device are stored in memory, such as NVRAM, resistant to the removal of power. In another, actual parameters of the EP device are learned during calibration and stored in the same memory. A controller has local or remote access to the memory and makes comparisons of the pre-characterized and learned parameters to implement corrections. Especially, scan alignment corrections are implemented to alter future scanning of scan lines of latent images on a photoconductor whereby the scan lines are formed in alternating directions. Certain contemplated parameters include, but are not limited to, a scan detect to print distance from a sensor to the start of imaging, temperature, pressure, a scanning mechanism drive signal parameter, such as pulse width, or sensor delay information.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to temperature. A moving galvanometer or oscillator reflects a laser beam to create forward and reverse scan lines of a latent image. During use, the actual ambient temperature is obtained and used make corrections to improve print quality, such as by producing the latent image with a signal altered from an image data input signal to help ensure proper alignment of the forward and reverse scan lines.

Abstract: A method of producing an image that can eliminate an f? lens is provided. This method of producing an image includes producing the image from a plurality of dots with varying intervals that are to be formed by linearly scanning an image forming surface with light that has been modulated using image data for producing by a polygon mirror that rotates at a constant angular velocity, and generating, before the producing the image, the image data for producing to form the image with the plurality of dots with varying intervals from original image data that forms a target output image with a plurality of dots with constant intervals. The step of generating the image data for producing includes setting a state of a first dot included in the plurality of dots with varying intervals at a state of a second dot that is included in the plurality of dots with constant intervals obtained from the original data and is at a position that is close to a position of the first dot.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: An optical scanning device includes a deflecting unit, a first sensor, and a modulating system. The deflecting unit deflects a plurality of beams in a main scanning direction to a writing area of a surface to be scanned for scanning the writing area. The first sensor detects a beam to be incident on a point on a first side of the writing area, and outputs a signal in response to detected beam. The modulating system modulates the beams in synchronization with the signal output from the first sensor.

Abstract: An optical scan apparatus which deflects a plurality of light beams to scan a write region on a scan surface in a main scan direction is configured to include a light source which has a plurality of emission portions emitting the plurality of light beams arranged two-dimensionally on a plane in parallel to the main scan direction and a sub scan direction perpendicular to the main scan direction; a deflector which deflects the plurality of light beams from the plurality of emission portions; a light receiving element which receives the light beams and outputs a synchronous detection signal in accordance with the received light beams; and a control unit which selectively controls any one of the emission portions to emit a light beam upon each scanning and allows the light beam from the selected emission portion to be incident on the light receiving element via the deflector.

Abstract: An apparatus includes: a position detection section which detects the position of the apparatus at predetermined detection timing; a light source section which emits light at light emitting timing synchronized with the detection timing; an image-taking section which takes the image of a photographic subject by using the emitted light; and an image processing section which matches the position data indicating the detected position of the apparatus and the image data obtained by the image-taking.

Abstract: At least one exemplary embodiment is directed to an image forming apparatus using a plurality of laser beams that includes a unit configured to detect a main scanning synchronization signal per beam while performing a laser light amount control per beam for each predetermined line, and a unit configured to produce a main scanning synchronization signal of a beam whose main scanning signal is not detected, by using the main scanning synchronization signal of the detected beam.

Abstract: In an electrophotographic (EP) device, methods and apparatus include determining a delay of one or more sensors (hsync) to accurately know when to start the process of scanning latent images. In one aspect, the sensor includes a leading and trailing edge defined along a direction of laser beam scan travel. Determining the delay includes learning a position of a laser beam on the sensor at a time when a controller connected to the sensor receives a signal from the sensor indicating the sensor is being sufficiently impinged upon by the laser beam. It also includes learning a latest possible position of the laser beam along the direction of laser scan travel where the laser beam can be turned on and still have the sensor assert a signal indicating it has been sufficiently impinged upon by the laser beam. Bi-directionally scanning EP devices are also disclosed, including controllers, photoconductors, sensors, etc.

Abstract: An image forming apparatus including: optical sensor to receive a bias current and to divide the bias current into two output currents, according to positions of a light beam on the optical sensor; and a signal processor to detect horizontal synchronization signals using the output currents, to calculate a positional deviation of the horizontal synchronization signals, and to control a recording time of video data according to the positional deviation.

Abstract: Systems and methods are disclosed for determining and generating horizontal synchronization signals for a laser printer having a multi-facet rotating mirror. Each horizontal synchronization signal is determined based on measurements of the facets. The measurements are reflective of the configuration of the mirror and may be acquired using one horizontal synchronization sensor. Respective pseudo horizontal synchronization signals may be generated for multiple emitters based on the measurements obtained with the single horizontal synchronization sensor.

Abstract: An apparatus for providing delay signals to perform print scan line synchronizations within a laser printer is disclosed. The apparatus includes a voltage-control oscillator, a frequency divider and multiple output control modules. The voltage-control oscillator converts a clock signal to a higher frequency signal. The frequency divider then reduces the frequency of the higher frequency signal. Then, each of the output control modules generates a delay signal, and each of the delay signals is delayed by no more than one tenth of a clock cycle from an adjacent one of the delay signals.

Abstract: An optical scanner unit includes an LD unit, a polygon mirror deflecting a light beam, an optical scan system focusing the light beam from the polygon mirror on a photoconductive drum to form an electrostatic latent image, and a synchronous detector receiving a part of the light beam to detect a write start position on the photoconductive drum in main scan direction. The synchronous detector is fixed on a portion of a housing at predetermined angles in main and sub scan directions relative to an incidence angle of the light beam on the synchronous detector.

Abstract: A laser light control device for an image forming apparatus designed to improve the auto power control (APC) accuracy and to reduce the control time. A multifunctional optical element has a plurality of different optical characteristics. A detecting unit is adapted to detect laser light from the semiconductor laser. A control unit is adapted to perform control of the write start position of the laser light in the main scanning direction and control of the quantity of the laser light by detecting the laser light by means of the detecting unit after passage of the laser light through the multifunctional optical element.