Abstract: Disclosed are an apparatus for and a method of correction color registration in an electro-photographic printer. An apparatus for correcting color registration in an electro-photographic printer, in which exposure start points of each color unit for a photosensitive drum are adjusted to superpose images developed in a plurality of colors on matching positions of a transfer belt, includes an exposure unit to project light beams on the photosensitive drum to form latent images of one or more marks for each color unit. A developing unit is also disclosed to generate developed images by developing the latent images of the marks and a mark sensing unit is provided to detect the developed images transferred on a surface of the transfer belt for a predetermined time period. A color registration controller stores information on time points at which the developed images are detected and compares the number of the time points with the number of the marks.

Abstract: An image processing apparatus which comprises a RAM acting as a shared memory for storing image data, and an image processing board, connected to the RAM through a PCI bus acting as a general-purpose bus, for performing raster conversion to the image data and performing a necessary image process to the converted data by using a line memory is provided. In this apparatus, in a case where the image processing board can not input or output the data from or to the PCI bus, it is controlled not to generate a sync signal used for a process in the image processing board, whereby a stable operation is possible in an image forming apparatus and an image processing method which include the image processing apparatus.

Abstract: In a beam irradiation device of the present invention, laser beams emitted from a semiconductor laser impinge on an irradiation lens supported by a lens actuator. The laser beams that have passed through the irradiation lens change in outgoing angle in the direction of a y-z plane as the lens actuator is driven. A laser beam scan in the target region is thus performed. A part of the laser beams that have passed through the irradiation lens is reflected and separated by a beam splitter. The separated beams are converged on a PSD through a converging lens. A DSP control circuit monitors a scan position of the laser beams that have passed through the irradiation lens based on a signal from the PSD. When an irradiation position has deviated from a scan trajectory, the DSP control circuit controls an actuator driving circuit to draw the irradiation position back onto the scan trajectory. This beam irradiation device can realize a smooth and stable beam scan operation with a simple construction.

Abstract: A scanning unit of an image-forming device has a polygon mirror for deflecting a laser beam across the surface of a photosensitive member. A disc that rotates together with the polygon mirror is provided with a reference mark. When the reference mark passes a photointerrupter, the photointerrupter detects the rotating position of the polygon mirror. A counter measures the number of pulses in a reference clock from the moment the photointerrupter detects the reference mark until a sensor provided in a measuring device detects the laser beam deflected by the polygon mirror, and the value of the counter is stored in memory as timing data. When the scanning unit is subsequently mounted in an image-forming device, the count value stored in memory is used to control the exposure timing for irradiating the photosensitive member in the image-forming device with the laser beam.

Abstract: A printing apparatus with a plate-making mechanism with a data modification part for modifying width of an original image in a subscan direction by computation to obtain a modified image and a controller for recording an image with its length in a main scan direction modified by shifting a writing clock in image recording. This allows reduction in the amounts of computation as compared with a case where modification against extension of a paper in the main scan direction and subscan direction is performed only by computation and makes it easy to control modification as compared with a case where the modification in the main scan direction and subscan direction is performed only by shifting the writing clock and a moving clock for a writing head. Thus, it becomes possible to easily correct the influence of extension of paper in printing.

Abstract: An optical scanning device and method of optical scanning are provided. The optical scanning unit includes a resonant mirror controller scanning light emitted from a laser diode on a photoconductive drum, a first receive light sensor which receives the light scanned by the resonant mirror controller, and outputs a first horizontal synchronization signal which determines a start position of optical scanning according to the received light, and a video signal controller, responding to the first horizontal synchronization signal output from the first receive light sensor, controls the laser diode so that light corresponding to a video signal is emitted. In the optical scanning unit, a video signal controller can receive a plurality of horizontal synchronization signals (SOS; Start of Scan) through only one input pin irrespective of the number of receive light sensors which generate horizontal synchronization signals (SOS; Start Of Scan), which correspond to a start position of optical scanning.

Abstract: A pixel position specifying method in an image forming device, the method measuring positions of exposure beams of the respective exposure heads and specifying pixel positions of junctures of the exposure heads, the method includes: using a beam position detecting mechanism to measure the positions of the exposure beams; detecting a first exposure beam position on an image receiving surface provided at the beam position detecting mechanism, by turning on a first connecting pixel near a juncture of a first exposure head; detecting a second exposure beam position on the image receiving surface, by turning on a second connecting pixel near a juncture of a second exposure head and moving the beam position detecting mechanism in the Y axis direction; and specifying connecting pixel positions from a moving amount of the beam position detecting mechanism in the Y axis direction and positions of exposure beams of the exposure heads.

Abstract: An image forming apparatus in which the intensity of a light beam used to form a latent image is switched in response to a change in resolution. A laser emits a light beam for forming a latent image on a photosensitive drum. A polygon mirror scans the emitted light beam. BD sensors detect the scanned beam. A timing controller selects the preferable timing from a storage device table according to the intensity of the light beam or the resolution when controlling the light emission timing of the lasers in response to a detection of timing of the detected light beam.

Abstract: An electrophotographic device comprises a printhead having at least one laser associated with a corresponding photoconductive surface. Where multiple laser beams are associated with the same photoconductive surface, the laser beams are spaced a predetermined distance from one another in a process direction, which is orthogonal to a scan direction in which the laser beams are swept. The electrophotographic device operates at one of at least two image transfer rates. A controller in the electrophotographic device selectively directs image data to the printhead based, at least in part, upon the selected image transfer rate, the facet resolution, and/or the desired output image resolution. The print speed can thus be adjusted over a relatively wide range.

Abstract: A scanning system for a printer or scanner that has a beam source that produces a light beam at a point of origin and has a scanning mirror that sweeps the light beam from a position “A” to a position “B.” A lens receives the light beam from the scanning mirror and directs the light beam as a scanning beam to an image plane surface. A first synchronizing mirror intercepts and reflects a light ray to a photo detection system when the scanning beam is at a position “A?” that is in the vicinity of position “A” and between position “A” and “B”. A second synchronizing mirror intercepts a light ray when the scanning beam is at a position “B?” that is in the vicinity of position “B” and between position “A” and “B”, and reflects the light ray to a folding mirror that reflects the light ray to the photo detection system. In some configurations two photo detection systems are used in lieu of the folding mirror.

Abstract: Disclosed in a multi-beam optical scanning apparatus which includes a light source unit including a plurality of radiation points disposed with being spaced from each other in a main scanning direction, and a deflecting unit for deflecting a plurality of light beams radiated from the light source unit toward a surface to be scanned.

Abstract: An image forming apparatus having: a plurality of scanners, each of the scanners having a rotary polygonal mirror; a position detecting section for generating an image start reference signal in a main scanning direction; a PLL control section for controlling a rotation number of the mirror on a basis of a reference frequency signal of the mirror and a pulse signal generated per one rotation of the mirror; and a phase control section for detecting phase difference of each mirror on the basis of the image start reference signal in the main scanning direction in the plurality of the scanners, controlling a phase of the reference frequency signal of each mirror, and correcting image deviation in a sub-scanning direction of an image formed by the plurality of the scanners.

Abstract: A multi-beam scanner includes light sources, a deflector deflecting the beams emitted from the light sources at an equiangular velocity, a scanning image-forming optical system guiding the deflected beams to a surface so as to be formed into light spots on the scanned surface, a light receiving device receiving the beams deflected toward optical write-in starting portions on the scanned surface as synchronizing beams, and a synchronizing beam optical system guiding the beams deflected toward the optical write-in starting portions on the scanned surface to the light receiving device. The scanning image-forming optical system includes two or more scanning positive lenses, with a region having a positive power in a main scanning direction on an optical write-in starting side, and each deflected beam received by the light receiving device passes through one or more but not all of the scanning positive lenses to be guided to the light receiving device.

Abstract: An optical recording apparatus includes a light source, a scanner, and a phase shift controller. The light source emits a light beam controlled to be lit on and off in synchronism with a pixel clock signal according to input image data. The scanner reforms the light beam emitted by the light source into a cyclic scanning light beam scanning in a main scanning direction a photosensitive surface moving in a sub-scanning direction. The phase shift controller performs an image magnification correction by a phase change for changing a phase of the pixel clock signal in units of one nth of a cycle of the pixel clock signal at one or more positions on the photoconductive surface in the main scanning direction, in which n is an integer greater than one. A method and apparatus of optical image forming is also described.

Abstract: In a pixel clock creation method and device, a high frequency clock is created. A scanning time needed to scan a predetermined scanning length is detected in accuracy of half a period of the high frequency clock to output a detection value indicating the detected scanning time. The detection value and a predetermined target value are compared to output a comparison result. A phase data is created based on the comparison result. A pixel clock whose phase is controlled based on both the high frequency clock and the phase data is created.

Abstract: A scanning line alignment compensation apparatus and method for a laser printer. The scanning line alignment compensation apparatus includes a laser scanning unit (LSU) having a first laser diode and a second laser diode and at least one sync signal detection sensor that generates a sync signal based on at least one of the first laser diode and the second laser diode based on selectively driving either of the first laser diode and the second laser diode, and generates at least one offset sync signal having first and second sensor detection periods based on the sync signal generated based on the at least one of the first laser diode and the second laser diode; a compensation unit compensating for first and second video data input in synchronization with a video clock based on the first and second sensor detection periods; and a laser diode control unit outputting control signals to control the first laser diode and the second laser diode based on the compensated first and second video data.

Abstract: An image signal with an overshoot is generated on a positive-going edge of an input image signal with an overshoot producing unit. Then, a light signal with an overshoot is outputted from a recording light source in response to the image signal with the overshoot supplied from the overshoot producing unit. The light signal outputted from the recording light source is applied to scan a photosensitive medium to record an area gradation image on the photosensitive medium.

Abstract: A bi-directional electrophotographic raster imaging system that sweeps a modulated light beam across an imaging region of a photosensitive surface to create both forward-going and reverse-going scanlines of dot data on the imaging region, and which compensates for image misalignment that may be caused by varying the power used to drive a laser light source that generates the modulated light beam. An SOS photosensor detects the beginning of each scanline in both forward and reverse directions, outputting an SOS signal used to create both forward and reverse margins. When the laser power is varied, compensating data is used to correct the forward and reverse margins to keep them aligned (straight), even though the beginning of the scanline locations for both forward and reverse scans are affected in opposite directions by an increase or decrease in laser power.

Abstract: A method for refining a length of a scan line, where the scan line is produced from a facet of a scanning device. The method includes the steps of: (a) acquiring a plurality of scan line lengths produced from the facet, (b) determining from the plurality of scan line lengths, an average scan line length for the facet, and (c) determining from the average scan line length, a scan line length correction for the facet. A method for measuring a length of a scan line includes the steps of: (a) charging an electrical current integrator to a voltage while a scan line is produced from a facet, (b) measuring the voltage, and (c) determining from the voltage, the length of the scan line produced from the facet.

Abstract: An optical exposure method and a device are used for forming patterns on a printed board wiring or semiconductor board. A single exposing region of a surface to be exposed is irradiated with a plurality of optical beams having different irradiating areas and different scanning pitches, such as, a peripheral area is irradiated with an optical beam having a smaller irradiating area and an inner area is irradiated with an optical beam having a larger irradiating area.

Abstract: A light beam scanning apparatus according to an embodiment of this invention includes a reflection unit for reflecting a light beam, a rotation unit for rotating the reflection unit, a rotation control unit for controlling rotation of the rotation unit, a rotational speed detection unit for detecting a rotational speed of the rotation unit, a light amount control unit for, before the rotational speed detection unit detects that the rotational speed has reached a predetermined rotational speed, controlling light emission of the light beam and controlling the light amount of the light beam to a predetermined value, and a light emission control unit for, after the rotational speed detection unit detects that the rotational speed has reached the predetermined rotational speed, controlling a light emission timing of the light beam.

Abstract: An optical beam scanning device includes plural light sources, a pre-deflection optical unit, a light deflection unit, a post-deflection optical unit, and a horizontal synchronization unit. One of the formed plural latent images is formed by plural light beams while the other latent images are respectively formed by one light beam, and the light deflection unit deflects the light beams forming the plurality latent images by one surface or integrally processed surface thereof. The horizontal synchronization unit is on a position of an upstream side of scanning lines forming the latent image formed by the plural light beams and detects that the light beam forming the latent image formed by the plural light beams reaches a predetermined position. The image forming apparatus employs the optical beam scanning device and controls timing to form images by the respective light beams with reference to a moment when the light beam to be detected reaches a predetermined position.

Abstract: This invention is to obtain a multi-beam scanning apparatus which always executes synchronization detection at the same timing to prevent any jitter, and an image forming apparatus using the apparatus. In a multi-beam scanning apparatus which guides a plurality of light beams emitted from a light source to an optical deflector, guides the plurality of light beams deflected by the optical deflector onto a target scanning surface through a scanning lens system, and guides some of the plurality of light beams deflected by the optical deflector to a synchronization detecting unit to execute synchronization using a sync signal obtained by the synchronization detecting unit, the synchronization detecting unit includes a BD slit which determines the synchronization detecting timing, and the BD slit has a smooth member.

Abstract: An image-forming apparatus is disclosed that includes at least one imaging optical system forming an electrostatic latent image on the scanning surface of a medium moving in a sub scanning direction by scanning the scanning surface in a main scanning direction by periodically deflecting a laser beam with a rotary deflector, a pixel clock generation part generating a pixel clock signal for controlling the emission timing of the laser beam and changing the phase of the pixel clock signal, a region setting part setting the length of each of multiple regions based on image writing magnifications in a line in the main scanning direction, the regions being formed by dividing part of the scanning surface corresponding to the line in the main scanning direction, and a phase control part controlling the changing of the phase of the pixel clock signal region by region based on the image writing magnifications.

Abstract: In a multibeam-type image printing apparatus, a process of adjusting a beam scanning position at which a photosensitive body is scanned is simplified. More specifically, consumption of a developing agent such as toner or the like is suppressed, and the time required for the adjustment process is shortened. A test pattern is formed on the photosensitive body using the first beam out of a plurality of beams, thereby detecting the irradiation position of the first beam with respect to the photosensitive body. Correction data for all the beams are generated on the basis of adjustment data as the detection result and predetermined beam information (information indicating a relative positional relationship between the plurality of beams on the photosensitive body). Image transfer clocks and scanning start positions are set on the basis of the correction data.

Abstract: An object is to obtain a multi-beam optical scanning apparatus in which a displacement of an image location of each of light beams emitted from a plurality of light emitting portions is reduced, and which is suitably usable in a high-speed and high-image-quality application, and an image forming apparatus using the multi-beam optical scanning apparatus.

Abstract: In a multi-beam scanning optical system, when at least three light fluxes emitted from a light source having at least three light-emitting points are deflected and reflected on a deflection unit and guided to a surface to be scanned by a scanning optical unit, at least three light fluxes are entered into a deflection surface of the deflection unit at irregular angles within a main-scanning section and entered into the surface to be scanned at an angle within a sub-scanning section, and provided that a variation in lengths of scanning lines which is caused when each of the at least three light fluxes is entered into the surface to be scanned at an angle within the sub-scanning section is represented as ?Y1, a variation in lengths of scanning lines which is caused when each of the at least three light fluxes is allowed to enter as a non-parallel light flux to the deflection surface within the main-scanning section is represented as ?Y2, and a variation in lengths of scanning lines which is caused from a differe

Abstract: In an image forming apparatus which uses a semiconductor laser as a light source, a semiconductor laser is controlled by adjustment of an image write-in clock, and a highly accurate scanning position alignment is performed with a simple structure. An optical unit scans a rotational photo conductor by a laser light output by a semiconductor laser. A photodetector detects the laser light output by the semiconductor laser at a predetermined position. An electrostatic latent image is formed by scanning the rotational photo conductor based on the laser light detected by the photodetector. By dividing a clock output from a high-frequency clock generation circuit, an image clock which synchronized with the output of the photodetector is generated, and the phase of the image clock is changed.

Abstract: A main control section controls a movable beam a such that a passage position thereof may come to a center of a gap between a sensor SK and a sensor SJ, and measures an output difference between a sensor SP and a sensor SO. In this case, the main control section successively measures an output difference between the sensors SP and SO while moving the movable beam a to the center of the gap between the sensors SK and SJ. Similarly, the main control section controls the movable beam a such that the passage position thereof may come to a center of a gap between the sensor SJ and a sensor SI.

Abstract: A scanning optical apparatus includes a light source capable of being modulated, a deflecting element for deflecting and scanning a beam emitted from the light source, a scanning optical element for imaging the deflected beam into a spot shape on a scanned surface, and an optical element for synchronous detection for directing the deflected beam from the deflecting element to a sensor to take the timing of image writing beginning. The scanning optical apparatus further inclueds a scanning position detecting device for making the optical axis of the optical element for synchronous detection and the principal ray of the beam from the deflecting element for taking the timing of image writing beginning coincident with each other, and detecting the position of the beam at a point having at least one image height separate from the optical axis of the scanning optical element.

Abstract: An imaging apparatus includes a controller communicatively coupled to a first laser, a second laser, a scanning device and a light sensor. The controller is configured to perform actions including controlling the first laser, the second laser and the scanning device to simultaneously scan the first light beam and the second light beam across an image region of the photoconductive substrate over a plurality of scans to form a latent image on the photoconductive substrate; activating only the first laser outside the image region between first successive scans of the plurality of scans to sense with the light sensor the first light beam; and activating only the second laser outside the image region between second successive scans of the plurality of scans to sense with the light sensor the second light beam.

Abstract: An image recording device, wherein deviation of an image-recording start position, which results from a difference in the amount of expansion and contraction based on temperature changes between a printing plate precursor, a rotating support, a mechanism for moving a recording head, and the like, is corrected so that an image can be recorded at a proper position. Temperature 1 near the rotating support is obtained by a first temperature sensor, and temperature 2 near the mechanism is obtained by a second temperature sensor. Then, an amount for correcting an image-recording start position is obtained from a correction table based on the temperatures 1 and 2 and on a size of the printing plate precursor, and the number of drive pulses for correction corresponding to the obtained amount of correction is outputted to a drive motor of the mechanism.

Abstract: A light scanning unit of the present invention can reduce the degree of variation in the quantity of light on a photosensitive body by a scanning position and can reduce a difference in density of an image which occurs at image formation.

Abstract: A method of correcting registration in an electrophotographic machine includes the steps of adjusting one of a right margin and a left margin by setting a time delay, determining a longest line length of a calibration pattern, and adjusting an other of the right margin and the left margin to match the longest line length.

Abstract: An optical head having a laser source of beams at an input end and image forming beams at an output end and a plurality of optical components arranged along the beams between the input and output ends to obtain an image on a photosensitive printing plate from the beams. The optical components include reflecting surfaces adapted to fold the beams several times between the input and output ends times in such a way as to reduce the width and height of the optical head. The folded beams are located in a plurality of parallel surfaces perpendicular to the image formed on the photosensitive printing plate. The optical head further includes optical components adapted to adjust the width, location, orientation and intensity of the image from the beams.

Abstract: A multi-beam scanner includes light sources, a deflector deflecting the beams emitted from the light sources at an equiangular velocity, a scanning image-forming optical system guiding the deflected beams to a surface so as to be formed into light spots on the scanned surface, a light receiving device receiving the beams deflected toward optical write-in starting portions on the scanned surface as synchronizing beams, and a synchronizing beam optical system guiding the beams deflected toward the optical write-in starting portions on the scanned surface to the light receiving device. The scanning image-forming optical system includes two or more scanning positive lenses, with a region having a positive power in a main scanning direction on an optical write-in starting side, and each deflected beam received by the light receiving device passes through one or more but not all of the scanning positive lenses to be guided to the light receiving device.

Abstract: A method for controlling an image forming apparatus for forming a color image by superposing images formed at image forming units, each provided for a corresponding one of a plurality of color components, includes a first skipping step of skipping part of a main-scanning synchronizing signal in a first image forming unit for forming an image of a first color component, a first generation step of generating a sub-scanning reference signal based on the main-scanning synchronizing signal skipped in the first skipping step, a first exposure-scanning control step of controlling exposure scanning in a second image forming unit based on the main-scanning synchronizing signal skipped in the first skipping step and the sub-scanning reference signal generated in the first generation step, a second generation step of generating a sub-scanning reference signal in the second image forming unit for forming an image of a second color component, based on the sub-scanning reference signal generated in the first generation ste

Abstract: A multi-beams optical scanning device is constituted such that a width in a main scanning direction of each of a plurality of light beams emitted from a light source unit is wider than a moving area in the main scanning direction in which a deflection facet of a deflection unit can move and exist when the plurality of light beams emitted from the light source unit are deflected toward an entire effective scanning area on the surface to be scanned and are deflected toward the synchronous detection means provided outside the effective scanning area.

Abstract: The timing sensors provided in the light-receiving part of a beam-detecting unit have different lengths in the sub-scanning direction. The beam-passing position sensors provided in the light-receiving part of the beam-detecting unit are longer than the timing sensors, in the sub-scanning direction. The intensity of a light beam is controlled in a reference-pitch measuring routine.

Abstract: It is an object of the present invention to provide a multi-beam scanning optical system, which can reduce relative deviation of a writing position of each light-emitting portion due to focus deviation of a synchronization detection optical device, and an image forming apparatus using the same. In the multi-beam scanning optical system having the synchronization detection optical device including a light source device, an incident optical device, a deflection device, a scanning optical device and a slit, each element is set such that relative deviation of a writing position of each light beam due to deviation of a focus position within a main scanning cross section is reduced by a first light beam limiting element provided between the deflection device and the slit and a conditional expression is satisfied.

Abstract: According to a beam control device of the present invention, if an exposure device including a light emitting section is instructed to form an image and a predetermined current is then supplied to an application specific integrated circuit and a main control section, then the main control section outputs an light emitting section on signal. Then, the light emitting section outputs light having its intensity changed according to image information.

Abstract: An apparatus to generate a laser beam detect signal includes a reflective mirror arranged on a part of an optical path of a laser beam which forms an electrostatic latent image on a photosensitive body, a beam detect lens to focus the laser beam reflected from the reflective mirror, and a printed circuit board having a photo diode sensor to detect the laser beam passed through the beam detect lens, generating the laser beam detect signal to synchronize a starting point of an image formation of the electrostatic latent image. The apparatus to generate a laser beam detect signal also includes a fixing part to secure the beam detect lens on the printed circuit board so that a center of an optical axis of the beam detect lens is aligned with a detection area of the photo diode sensor. Alternatively, the beam detect lens and the photo diode sensor may be integrally formed with each other. As a result, deterioration of printing quality due to errors from part allowance and an assembling process is prevented.

Abstract: A laser beam scanner converges a laser beam by using a first f? lens and a second f? lens in a main-scanning direction and in a sub-scanning direction, respectively, onto a photosensitive medium, thereby forming a scanning line on the photosensitive medium along the main-scanning direction. Before scanning the photosensitive medium, the laser beam that has passed through and been converged by the first f? lens, but not passed through the second f? lens, is guided to a beam detector and converged by a cylinder lens in the sub-scanning direction so that the laser beam falls within a detection area of the beam detector. The beam detector determines a scan start time by detecting the laser beam.

Abstract: A synchronizing circuit and a timing adjusting circuit set a position of an exposure area by beam scanning as an additional value of a first setting value set in dot unit corresponding to the scanning of a pixel clock period and a second setting value set in tap unit corresponding to the scanning of a period smaller than the pixel clock period. A CPU controls the synchronizing circuit and the timing adjusting circuit so that the exposed position becomes an objective position. The CPU changes the second setting value to a first predetermined value by increasing the first setting value by one dot, in the case that the additional value is increased to reach a first threshold.

Abstract: While scanning two laser beams that are separated by a prescribed distance d in the scanning direction, one of the beams is first irradiated onto a BD sensor at a timing t11. However, the sensor signal Vs emitted from the BD sensor changes only slightly at this time, and the amplified sensor signal Vg, which is a reverse amplification of the sensor signal Vs, does not reach the threshold level Vth. Subsequently, at a timing t12 the other laser beam is irradiated onto the BD sensor so that both laser beams are simultaneously irradiated on the BD sensor. At this time, the amplified sensor signal Vg rises enough to exceed the threshold level Vth, and the BD signal is outputted (switched to low level). By outputting a BD signal upon simultaneously receiving two laser beams in this way, stability of the BD signal is improved.

Abstract: An image forming apparatus shifts a scanning position on a surface scanned of each of a plurality of optical beams in a main scanning direction and a sub-scanning direction, and scans a plurality of lines simultaneously in the main scanning direction by a deflecting part. A synchronization detecting sensor detects the plurality of optical beams. A counting part counts a clock having a higher frequency than a dot clock in an interval between a synchronization detection point of a first beam and a synchronization detection point of a second beam, the first and second beams being included in the optical beams detected by the synchronization detecting sensor. A determining part determines a starting position of writing for each of the plurality of optical beams based on a counted value counted by the counting part.

Abstract: A recording material is angled and wound on a rotating drum. Distortion (inclination) of an image can be eliminated with a comparatively simple control system, and the occurrence of distortion when there is a change in image recording specifications can be prevented. For standard specifications, although image recording lines have helical movement tracks during image-recording, a peripheral end of a printing plate and a peripheral end of an image region can be made to be parallel with one another without distortion of the image region. In contrast, when instructed specifications differ from the standard specifications, a conventional image region becomes distorted because an inclination angle of the printing plate cannot be varied. Accordingly, in a case in which instructed specifications differ from the standard specifications thus, image data is shifted in a sub-scanning direction by soft processing, and the distortion is alleviated.

Abstract: It is an object of the present invention to provide an image forming apparatus that is capable controlling the rotational speed of a polygon motor so as to reduce variations in the rotational speed of the polygon motor to the minimum possible level and enable steady rotation of the polygon motor with ease in controlling the rotational speed of the polygon motor to a target speed. When a photosensitive drum is exposure-scanned while the traveling direction of an exposure laser beam is deflected by the polygon mirror, a polygon motor for driving the polygon mirror is controlled according to target periods or target speeds of the polygon motor, which are determined for respective mirror planes of the polygon mirror.

Abstract: A laser imaging device is described. The laser imaging device includes a first laser, a second laser, and a controller. The first laser provides a first scan line having a first starting point, and the second laser provides a second scan line having a second starting point based on an adjusted beam detect signal. The controller is configured to generate the adjusted beam detect signal using a delay code and a beam detect signal associated with the second laser to substantially horizontally align the second starting point with the first starting point.

Abstract: An image forming apparatus includes at least one image forming mechanism configured to form an image based on image data. Each image forming mechanism includes an optical system, a sensor, an electronic circuit, and a controller. The optical system scans a photosensitive member with a light beam based on image data. The sensor detects the light beam and the electronic circuit stores a correction data table containing light amount data of the light source and corresponding start position shift amount data. The controller controls a light amount of the light source and adjusts a start position of image recording on the photosensitive member in accordance with a sync detect signal. The controller includes a write start position correction unit that adjust the start position of the image recording based on a start position shift amount data when the light amount varies.