Abstract: An optical scanning device includes a plurality of scanning optical systems arranged in a main scanning direction. Each of the scanning optical systems includes a plurality of light sources emitting light beams, a light source driving circuit modulating the emitted light beams separately, and a deflector causing the light beams to perform scanning. At least one of the scanning optical systems includes a light source selection part selecting one of the light sources of the one of the scanning optical systems.

Abstract: An image forming apparatus is provided which not only transmits optical signals of image information and optical signal for synchronizing from the video controller to the print engine using a single optical fiber and without using a special synchronization optical fiber, but also transmits a synchronizing optical signal reflected by the SOS mirror on the print engine side simultaneously in the reverse path to the video controller, such that the number of lines are reduced in the layout, external noise and emitted noise are reduced, and the interior of the image forming apparatus is consolidated making handling and assembly easier. The apparatus transmits optical signals over an optical fiber, scans a photosensitive drum via a beam emitted from the optical fiber and detects the beam at a detection position disposed outside the image region, and synchronizes the main scan direction based on the detected beam.

Abstract: A system and related methods for automatically identifying media type in a printing device media tray is presented. The system comprises a controller, and an optical sensor, communicatively coupled to the controller, wherein the sensor is positioned to locate and identify a code containing media type information from a next available piece of print media, and to generate a signal to the controller based, at least in part, on the identified code.

Abstract: In an image forming apparatus such as a digital copying machine using a multi-beam optical system, a printing area can be set in the unit equal to or smaller than a clock for image formation by use of a delay pulse for each light beam and the exposure position in the light beam scanning direction (main scanning direction) is always precisely controlled by selecting an optimum set value while the actual light beam position is being checked by use of a sensor.

Abstract: An optical scanning apparatus includes a light source, a deflector with a deflecting/reflecting surface which deflects an incident light beam from the light source, an imaging optical system including at least one scanning optical element for leading the light beam deflected by the deflector onto a surface to be scanned and forming an image as a spot on the surface to be scanned and, a synchronization detector for obtaining a scanning start position signal with respect to a main scanning direction on the surface to be scanned. The scanning optical element is provided with a light-beam passage for allowing a light beam traveling toward the synchronization detector to pass through. The light-beam passage is provided in an inner portion of the scanning optical element located outside an effective portion of the scanning optical element.

Abstract: An optical scanning apparatus provides improved image quality by changing the amount of writing scale compensation for a pixel clock during a scanning cycle. A pixel clock generation unit of the optical scanning apparatus divides the scanning cycle into multiple division periods. A phase change of the pixel clock is carried out for each of the division periods. The phase change can also be different from scanning cycle to scanning cycle.

Abstract: A transition detection circuit detects a transition of a state of a pixel clock, and outputs a detection signal according to a timing of the detected state transition. A control signal generation circuit generates a control signal according to the detection signal and phase data indicating a transition timing of the pixel clock. A pixel clock control circuit causes the state of the pixel clock to transit according to the control signal.

Abstract: A method and an apparatus to control the scanning velocity and the amount of light to form a color image, including checking the rotation velocity of the scanning motor and varying the amount of light scanned according to the checked rotation velocity of the scanning motor. A motor clock signal to drive a scanning motor is generated without using an additional oscillator by dividing the frequency of a main clock signal, and the frequency of the motor clock signal is varied by varying a division ratio according to the formation velocity of the color image to be printed. Thus, power and noise are reduced by reducing the velocity of the scanning motor, and the amount of light irradiated to a photosensitive body is easily and finely varied according to the variation in the velocity. These effects are achieved without adding additional parts or logic circuits.

Abstract: A laser scanner is adapted to cause a laser beam to scan in the main-scanning direction by deflecting the laser beam by means of a deflecting optical system. A horizontal synchronizing signal is obtained by detecting the laser beam by means of a photodetector. Forced emission of laser beam is started after a predetermined time period since the detection of the laser beam, which predetermined time period is variable as a function of the rotary speed of the deflector section. With this arrangement, a horizontal synchronizing signal can be reliably detected if the rotary speed of the deflecting operation system fluctuates.

Abstract: A synchronization signal detector receives a laser beam each time it is scanned in a main scanning direction, and detects a synchronization signal from the received laser beam. An external circuit or the like sets a binary value-determining level for this detector. The binary value-determining level is so determined as not to generate a signal arising from stray light. By this determination, a synchronization error, which is due to stray light, is prevented without adding manufacturing steps to prevent the stray light or without incurring an increase in the cost needed for structural components.

Abstract: A light beam scanning apparatus controls a scan position for a light beam with a first light volume so that output from a sensor is adjusted to a target value. Further, the light beam scanning apparatus controls a scan position for the light beam with a second light volume so that output from the sensor is adjusted to the target value.

Abstract: The write lines of a color laser printer are maintained substantially equal throughout the printer's operation by an electronic control arrangement. At the factory, the write lines on all photoconductors of the color laser printer are calibrated to be substantially equal, and the ratio of each write line to a measuring line for each photoconductor is ascertained. During operation of the printer, the length of each of the measuring lines is periodically determined through counting the number of PELslice clock timing pulses produced from a PELslice clock operating at a fixed frequency determined during factory calibration. The length of the write line is determined by the product of the length of the measuring line and the factory calibrated ratio of the length of the write line to the length of the measuring line.

Abstract: Forming an image by utilizing a scanning device for scanning a color image for each color element, a reading device for reading image data for each scanned line, a rotary polygon mirror for deflecting, in a main scan direction, a modulated light beam that is based on the image data for each read line, so that an image holding member that is rotated in a sub-scan direction is scanned by the deflected light beam and a latent image is formed thereon, a first generation device for determining whether the light beam deflected by the rotary polygon mirror has scanned a predetermined location, and for generating a main scan start reference signal, and a second generation device for generating a sub-scan start reference signal in synchronization with the rotation of the image holding member, a first control device that controls the rotary polygon mirror and the rotary image holding member, so as to maintain a phase difference between the sub-scan start reference signal and the main scan start reference signal, no mat

Abstract: A light beam is scanned in the main scanning direction on a scanned face. The light beam is detected by a pair of sensors arranged on the scanned face or a position equivalent thereto and is converted to an electric signal. A processing circuit having a plurality of operational amplifiers corrects electric signals from the pair of sensors based on a correction signal and integrates a difference between these electric signals. A correction amount of the correction signal is set based on a value integrated by the processing circuit and an offset amount present in the processing circuit.

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: A method for determining a scan line error for a scan line, wherein the scan line is produced from one of a plurality of facets of a rotating reflector of a scanning device. The method comprises the steps of (a) determining a difference between a time of an occurrence of a point in a scan line produced from a first facet and a time of an occurrence of a point in a scan line produced from a second facet, and (b) determining from the difference, a scan line error for the scan line produced from the first facet.

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: A system and method are provided for microlithographic writing on photosensitive substrates, and especially high precision printing of patterns, such as photomasks, for semiconductor device patterns, display panels, integrated optical devices and electronic interconnect structures. The method includes the steps of detecting significant temporary writing error conditions and interrupting the writing process as a response to a detection of such an error condition. Thereafter a support table is reversed to the position it had when the writing was interrupted, and the writing process is restarted at the same position where the writing was interrupted when the error condition ceases to exist.

Abstract: A laser scanning apparatus, can suppress the unnecessary emission of a laser beam for a photosensitive drum, can prevent the degradation of the photosensitive drum, and can prolong the life time of a laser, using simple configuration. An image forming apparatus includes this laser scanning apparatus, and a method for starting the laser scanning apparatus. A laser scanning apparatus performing exposure with a laser beam predicts a time elapsing until completion of start on the basis of initial start conditions, shuts off the laser beam during the time predicted, emits a laser beam after the time predicted elapses, and detects completion of start.

Abstract: The sensor for converting a light beam into an electric signal is formed by a pair of symmetrical saw-toothed patterns with a narrowed width for marginally located teeth. The patterns are arranged interdigitally on the surface to be scanned or at a position equivalent to the surface. The difference of the output signals from the patterns is integrated to determine the scanning position of the light beam.

Abstract: An image forming apparatus includes a semiconductor laser that irradiates a laser beam modulated based on an image modulation signal, a scanning device that scans an image carrier with the semiconductor laser beam, and a pixel clock generating device that generates a pixel clock that controls the laser beam. The pixel clock includes a plurality of pulses having a prescribed normal width constituted by a prescribed number of fractions (N), and substantially periodically includes one or more pulses having a greater width constituted by a number of fractions of (N) plus (M).

Abstract: A signal is generated which is active only during an interval of taking one pulse of a series of output pulses of said synchronization detecting sensor, but is not active during an interval of taking more than one pulse thereof. Then, synchronization detection pulses are separated from the pulses output by the synchronization detecting sensor for the respective colors by using the thus-generated signal.

Abstract: An image forming apparatus that forms an image by scanning a recording medium with a plurality of light beams that are modulated by individual image forming signals respectively corresponding to the light beams. A beam detecting device detects the plurality of light beams at preset positions and outputs corresponding detection signals. At least one delay device delays each of the detection signals from the beam detecting device by an arbitrary time period which is predetermined individually for each of the detection signals. A reference clock signal generating device generates a plurality of reference clock signals on the basis of delayed detection signals output from the at least one delay device. The image forming apparatus performs an image forming operation according to the plurality of reference clock signals.

Abstract: An optical signal control process and circuit providing an improved electronic photography method reproduction apparatus. The reproduction apparatus has a data transmitting unit converting data to be printed to a series of video data in accordance with a first clock signal and transmitting the converted video data in response to a horizontal synchronization signal applied with a predetermined time interval, and a printing control unit for controlling a mechanism used to print the video data by sending electrical signals, providing beam data used to switch the light generation of a light source element controlled by chopped chopping video data applied to the light source element, and generating the horizontal synchronization signal on the basis of a beam detection signal produced by the light source element.

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.

Abstract: An optical scanning apparatus has an incident optical system for causing a light beam from a light source to be obliquely incident in a sub-scanning cross-section on a deflecting surface of an optical deflector, and an imaging optical system for forming, on a scanned surface, an image of the light beam deflected by the deflecting surface.

Abstract: A pixel clock pulse generating apparatus for use in an image forming apparatus includes high frequency clock pulse and pixel clock pulse generators. The high frequency clock pulse generator generates relatively high frequency clock pulses. The pixel clock pulse generator generates pixel clock pulses based on the phase data for instructing a transition time of pixel clock pulses and the high frequency clock pulses.

Abstract: Two sawtooth sensor patterns are combined so that they engage with each other. These sensor patterns are arranged so that a light beam passes sawtooth portions in a horizontal scan direction. A light beam's scan position is determined by integrating a difference between output signals from these sensor patterns. It is possible to provide a highly sensitive circuit for processing signals from the sensors and to improve detection accuracy for light beams.

Abstract: An image forming apparatus for accurately correcting misregister between images and effecting image formation is an apparatus for forming images by a plurality of image forming portions each having an image bearing member and a scanner unit for deflecting and scanning a light beam in conformity with an image signal and writing an image onto the image bearing member, and has an image signal outputting portion for outputting the image signal in conformity with a partly masked horizontal sync signal, and is designed to change the mask timing of the horizontal sync signal in conformity with the misregister amount among the images and to change the phase of a rotation reference signal for the control of the rotation of the scanner unit.

Abstract: A multibeam scanner capable of scanning an image forming area with constant beam amounts of laser beams. The multibeam scanner of the invention performs automatic power control (APC) on each of a plurality of beam emitting points one by one during corresponding time durations, respectively, in a non-image forming area. The laser beam emitted last among the plurality of laser beams is controlled to reach a predetermined beam detecting position within the corresponding time duration. Before scanning the image forming area, the multibeam scanner determines a scan start timing upon the detection of the laser beam emitted at the beam detecting position, which has been stabilized during APC. This arrangement allows the laser diode to avoid wasting time again and again, as rise time for stabilizing the laser beam for performing APC and for identifying the scan start timing, and to secure the time durations as long as possible.

Abstract: An image forming apparatus includes a semiconductor laser that irradiates a laser beam modulated based on an image modulation signal, a scanning device that scans an image carrier with the semiconductor laser beam, and a pixel clock generating device that generates a pixel clock that controls the laser beam. The pixel clock includes a plurality of pulses having a prescribed normal width constituted by a prescribed number of fractions (N), and substantially periodically includes one or more pulses having a greater width constituted by a number of fractions of (N) plus (M).

Abstract: An image recording apparatus includes a reference clock signal generating unit which generates a reference clock signal; a light beam generating unit which generates a plurality of light beams; a beam detect sensor which detects the plurality of generated light beams to output a plurality of light beam detection signals; an image clock signal. generating unit responding to the reference clock signal and the plurality of light beam detection signals to successively generate a plurality of image clock signals. These clock signals have the same period, and correspond to the plurality of light beam detection signals.

Abstract: Four beams are caused to scan a scanning surface in the main scanning direction in parallel. The beams expose the target area between two optical sensors, not the surface of a photosensitive drum, to produce correction data to correct shifts in the exposure positions of the four beams in the main scanning direction with an accuracy of less than a small fraction of one pixel. On the basis of the correction data, an actual image formation area is set on the photosensitive drum. This makes it possible to always control the relative exposure scanning position accurately even when the relationship between the main scanning positions of the light beams is unknown.

Abstract: A circuit for controlling scanning of light includes a detection-signal processing unit which generates a detection signal indicative of a timing at which a light beam hits a predetermined reference position, and a clock-generation unit which generates a clock signal in synchronism with the detection signal such that a timing of the clock signal is adjustable by the detection signal independently of a length of one clock cycle of the clock signal, wherein the clock signal synchronizes the light beam.

Abstract: The invention concerns a clock-generating circuit, which generates dot clock pulses for driving a light-emitting element employed in an optical-writing section of an image-forming apparatus and has a function of canceling f&thgr; property errors caused by a f&thgr; lens employed in the image-forming apparatus. The clock-generating circuit includes a digital-delay dot clock adjusting section to adjust timings of rising-edges or falling-edges of the dot clock pulses generated by changing a selection for a plurality of delayed-clock pulses, which are generated by delaying clock-pulses, outputted from a reference oscillator, in slightly different delay times; and a controlling section to control a selecting operation for the plurality of delayed clock pulses, performed in the digital-delay dot clock adjusting section, so as to compensate for f&thgr; property errors caused by the f&thgr; lens employed in the optical-writing section.

Abstract: Two sawtooth sensor patterns are combined so that they engage with each other. These sensor patterns are arranged so that a light beam passes sawtooth portions in a horizontal scan direction. A light beam's scan position is determined by integrating a difference between output signals from these sensor patterns. It is possible to provide a highly sensitive circuit for processing signals from the sensors and to improve detection accuracy for light beams.

Abstract: A synchronization signal detector receives a laser beam each time it is scanned in a main scanning direction, and detects a synchronization signal from the received laser beam. An external circuit or the like sets a binary value-determining level for this detector. The binary value-determining level is so determined as not to generate a signal arising from stray light. By this determination, a synchronization error, which is due to stray light, is prevented without adding manufacturing steps to prevent the stray light or without incurring an increase in the cost needed for structural components.

Abstract: A laser scanner is adapted to cause a laser beam to scan in the main-scanning direction by deflecting the laser beam by means of a deflecting optical system. A horizontal synchronizing signal is obtained by detecting the laser beam by means of a photodetector. Forced emission of laser beam is started after a predetermined time period since the detection of the laser beam, which predetermined time period is variable as a function of the rotary speed of the deflector section. With this arrangement, a horizontal synchronizing signal can be reliably detected if the rotary speed of the deflecting operation system fluctuates.

Abstract: A laser scanning system including a wavelength tunable laser generating and emitting a laser beam having tunable wavelengths, and at least one photonic crystal receiving the laser beam emitted from the wavelength tunable laser. The photonic crystal deflects the received laser beam, during propagation within the photonic crystal, at an angle depending on the wavelength of the laser beam, and emits the deflected laser beam at various angles of emission depending on the angle deflected in the photonic crystal to scan the laser beams over the surface area of a body to be scanned. Non-linearities found in the wavelength versus scanning beam position relation are corrected with position sensors provided at both ends, and in between positions, of the beam scanning range on the photosensitive drum. With this configuration of the position sensors, the non-linearities are corrected and also beam scanning with high precession becomes feasible.

Abstract: A method of setting a plurality of margins in an electrophotographic machine includes setting a top margin for a reference color black by establishing a first time delay between a vertical synchronization signal and a first line. A right margin or a left margin for the reference color black is set by establishing a second time delay between a horizontal synchronization signal and a start of printing. The other of the right margin and the left margin is set by adjusting a scan speed of a laser beam across a photoconductive element and adjusting a process speed in the cross-scan direction including the speed of the photoconductive element, image accumulation member, and print medium. A bottom margin is set by adjusting the process speed. The other three color planes, cyan, magenta and yellow are then registered or aligned to the reference color plane, black.

Abstract: An optical scanning system of a printer includes an optical scanning unit including a light source, a rotating polygonal mirror having a plurality of mirror surfaces for deflecting light emitted from the light source toward a photoreceptor web, and a driving source for driving the rotating polygonal mirror.

Abstract: The write lines of a color laser printer are maintained substantially equal throughout the printer's operation by an electronic control arrangement. At the factory, the write lines on all photoconductors of the color laser printer are calibrated to be substantially equal, and the ratio of each write line to a measuring line for each photoconductor is ascertained. During operation of the printer, the length of each of the measuring lines is periodically determined through counting the number of PELslice clock timing pulses produced from a PELslice clock operating at a fixed frequency determined during factory calibration. The length of the write line is determined by the product of the length of the measuring line and the factory calibrated ratio of the length of the write line to the length of the measuring line.

Abstract: At least two light beam detection units are spaced at a predetermined distance and provided in the scanning direction of a surface to be scanned. A light beam is emitted to the light beam detection unit provided on a scanning start side, by lighting a light beam source which is employed to scan the surface linearly during a scanning period equivalent to 1 dot during scanning. A light beam is emitted to the light beam detection unit provided on a scanning end side, by lighting the light beam source during the scanning period after elapse of a light-off period computed from a previously designed scanning speed and the predetermined distance. Based on a detection result of the light beam detection unit provided on the scanning start side and a detection result of the light beam detection unit provided on the scanning end side, scanning characteristics required of the light beam are evaluated.

Abstract: A Direct Digital Synthesis pixel clock generator for use in electrophotographic printers. A controller receives a start-of-scan signal and a facet 0 signal. In response, the controller sends a pre-stored frequency control word to a Direct Digital Synthesis Oscillator. The Direct Digital Synthesis Oscillator sends pulses at a frequency that depends on the frequency control word to a Digital Phase Shift Circuit. The controller also applies a sequence of delay profile words to the Digital Phase Shift Circuit. Each delay profile word causes the Digital Phase Shift Circuit to delay a contemporaneous pulse from the Direct Digital Synthesis Oscillator between 0° and 360° degrees, with the actual delay depending upon the delay profile word. The delay profile words are selected such that scan line pixels are “adjusted” in position. A phase-locked-loop circuit integrates and smoothes the frequency step changes.

Abstract: An optical scanning apparatus includes a light source, a deflector with a deflecting/reflecting surface which deflects an incident light beam from the light source, an imaging optical system including at least one scanning optical element for leading the light beam deflected by the deflector onto a surface to be scanned and forming an image as a spot on the surface to be scanned and, a synchronization detector for obtaining a scanning start position signal with respect to a main scanning direction on the surface to be scanned. The scanning optical element is provided with a light-beam passage for allowing a light beam traveling toward the synchronization detector to pass through. The light-beam passage is provided in an inner portion of the scanning optical element located outside an effective portion of the scanning optical element.

Abstract: Distortions, wherein a recording image is inclined relative to a printing plate, are removed when image data from a computer are recorded spirally in recording bands, having a predetermined band width, of a plurality of picture elements on the printing plate which is wound on a drum. Printing plate exposure apparatus comprises the printing plate being wound spirally on the drum such that an extension line of a side edge line of the printing plate is shifted a band width after one drum revolution. The printing plate exposure apparatus further includes: an exposure unit for recording the image data in the recording bands on the printing plate; a moving mechanism for moving the exposure unit by one band width along a drum axial direction relative to the drum during one revolution of the drum; and a timing mechanism for adjusting a band recording start position of the image data for each rotation of the drum so as to set a top edge line of the recording image parallel to a top edge line of the printing plate.

Abstract: An optical scanning device is provided with a light source, a scanning system, a light receiving unit having a plurality of light receiving elements arranged in a main scanning direction, a resonance amplifying system that amplifies the light receiving signals of the light receiving elements. A clock signal is generated based on the resonance amplified signals. Further, a delay signal is generated to wait for stabilization of the clock signal. A synchronizing signal is generated based on the clock signal and the delay signal.

Abstract: An electrophotographic imaging device uses a transition placement device to position transitions in a stream of video data. A rasterizer included in the electrophotographic imaging device generates pixel data bytes based upon data received from a computer defining an image. A converter generates codes specifying positions of transitions within a pixel time period corresponding to a pixel data byte. The transition placement device includes a phase measuring device to measure a timing offset between an active edge of a beam detect signal and a rising edge of a reference clock. A transition adjustment device adjusts the positions of the transitions specified by the codes relative to the rising edge of the reference clock using the timing offset. Transition generation logic generates the transitions for the stream of video data using the adjusted transition positions received from the transition adjustment device.

Abstract: To provide a laser scanning apparatus, which can suppress the unnecessary emission of a laser beam for a photosensitive drum, can prevent the degradation of the photosensitive drum, and can prolong the life time of a laser, with using simple configuration, an image forming apparatus using this laser scanning apparatus, and a method for starting the laser scanning apparatus. A laser scanning apparatus performing exposure with a laser beam predicts a time elapsing until completion of start on the basis of initial start conditions, shuts off the laser beam during the time predicted, emits a laser beam after the time predicted elapses, and detects completion of start.

Abstract: A system is provided for rendering an output image on an image transfer surface using multiple optical scan paths in an image rendering device. The system includes a plurality of lasers, a plurality of scan time detectors, and processing circuitry. Each of the lasers is configured to generate an optical scan path on the surface. Each scan time detector is associated with a corresponding laser and is operative to measure scan time of the laser along the respective optical scan path. The processing circuitry communicates with each scan time detector and is operative to generate a video signal having a video frequency associated with the scan time detected for the respective laser. A method is also provided.