Abstract: This invention obtains an image forming apparatus and image forming method capable of achieving a simple, low-cost arrangement by controlling memory write-in/read-out similarly to image signal generation using a single beam even when an image is formed using a plurality of light beams. Write-in of a first light beam image signal in a memory A starts before a first light beam image signal for previous scanning is completely read out from the memory A. Write-in of a second light beam image signal in a memory B starts after a second light beam image signal for previous scanning is completely read out from the memory B.

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 misalignment detector includes a light source, a synthesizing unit, a focusing unit, an image sensor, and a misalignment calculator. The light source, the synthesizing unit, the focusing unit, and the image sensor are arranged in such a manner that light illuminated by the light source passes through the synthesizing unit so as to illuminate the position detection pattern, gets reflected from the position detection pattern, passes through the synthesizing unit so as to be focused by the focusing unit on the image sensor. A misalignment calculator detects an amount of misalignment of the laser beams based on an image formed in the image sensor.

Abstract: The sensors SP and SO detect a position in the sub-scanning direction through which a light beam scanned by the scanning unit passes. The correction pulse generator corrects the amplitude of the position signal obtained by the sensors SP and SO. The integrator integrates the position signal corrected by the correction pulse generator, and outputs the integration value corresponding to the sub-scanning direction position. The CPU 51 adjusts the correction amount of the correcting unit (the amplitude of the pulse) such that the integration value output from the integrator falls within a target range. The target range is varied in accordance with the light beam position that changes due to an influence caused by a change in the surrounding temperature or the like.

Abstract: A multi-beam scan optical system and an image forming apparatus using the same are provided in which high-quality printing can be realized at high speed with a relatively simple construction.

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: An image forming apparatus is constructed to include an image bearing member which is rotatably supported to bear a toner image, a light beam scanning section to simultaneously scan the image bearing member by a plurality of light beams so as to form an electrostatic latent image, a developing section to develop the electrostatic latent image into the toner image, a transfer section to transfer the toner image onto a recording medium, and an ON start timing adjuster to adjust an ON start timing of one of the plurality of light beams, based on an image tone of each of a plurality of patterns of an image pattern formed by the light beam scanning section.

Abstract: An apparatus to detect a laser beam at a predetermined location within a light scanning unit of an image forming apparatus in order to synchronize a start position at which an electrostatic latent image is formed on a surface of a photosensitive body is disclosed. The apparatus includes laser beam detection optics, which may be formed of either a single unit lens or a cluster of one or more lenses that are placed in close proximity of each other. The laser beam detection optics receives the laser beam directed in the direction of the photosensitive body at a predetermined location relative to the start position on the photosensitive body, redirects the received laser beam towards a sensor, and focuses the laser beam on the sensing area of the sensor. The close proximity of, or the fact that the laser beam detection optics, minimizes the possibility of misalignment during the assembly that may result in the improper focusing of the laser beam on the sensor sensing area.

Abstract: Provided are a multi-beam scanning optical system capable of implementing high-quality printing in relatively simple structure and at high speed, and an image forming apparatus using it. The multi-beam scanning optical system has an incidence optical unit for guiding a plurality of beams emitted from a light source unit having a plurality of light-emitting regions spaced apart from each other in a main scanning direction, to a deflector; a scanning optical unit for focusing the plurality of beams deflected by the deflector, on a surface to be scanned; and a synchronism-detecting optical unit for converging part of the plurality of beams deflected by the deflector, via a return mirror on a slit surface by a lens section, thereafter guiding the beams to a synchronism detector, and controlling timing of a scan start position on the surface to be scanned, by use of a signal from the synchronism detector.

Abstract: A multibeam scanning optical apparatus having a light source, an optical deflector, a scanning optical system, a detection optical element, and a photodetector. A plurality of light beams modulated in accordance with information signals are emitted from the light source and lead to the optical deflector. The light beams deflected by the optical deflector are then focussed on a surface to be scanned, typically a photosensitive drum, by way of the scanning optical system having an f&thgr; characteristic. Part of the deflected light beams are lead to the photodetector by a way of the detection optical system in order to control the timing of the start of scanning so that the centers of the scanning areas of the plurality of light beams agree with each other on the surface to be scanned.

Abstract: A compact light-beam deflecting device with a photonic crystal is provided, which has the capability of deflecting a light beam incident on the photonic crystal by a controlled angle to output a transmitted light beam having a desired direction from the photonic crystal. This light-beam deflecting device comprises the photonic crystal designed to have a photonic band gap wavelength that is different from a wavelength of a light beam to be incident on the photonic crystal, and a deflection controller for applying an amount of energy to the photonic crystal to deflect the light beam incident on a side of the photonic crystal, and to provide a transmitted light beam, which forms the desired angle with respect to the light beam, from the other side of the photonic crystal.

Abstract: A scanning type optical device comprises one optical characteristics measuring unit per color. Each optical characteristics measuring unit further includes three units. The first unit is provided on a writing start side within a scanning region, the second unit is provided on the other end side within the scanning region, and the third unit is arranged substantially at the center in the scanning region. Laser beams emitted from each of four semiconductor lasers are modulated based on signals detected by the three units in such a manner that a difference between a real image height and an ideal image height is reduced over the entire scanning region.

Abstract: Provided are a multi-beam scanning optical system capable of implementing high-quality printing in relatively simple structure and at high speed, and an image forming apparatus using it. The multi-beam scanning optical system has an incidence optical unit for guiding a plurality of beams emitted from a light source unit having a plurality of light-emitting regions spaced apart from each other in a main scanning direction, to a deflector; a scanning optical unit for focusing the plurality of beams deflected by the deflector, on a surface to be scanned; and a synchronism-detecting optical unit for converging part of the plurality of beams deflected by the deflector, via a return mirror on a slit surface by a lens section, thereafter guiding the beams to a synchronism detector, and controlling timing of a scan start position on the surface to be scanned, by use of a signal from the synchronism detector.

Abstract: Provided are a multi-beam scanning optical system capable of implementing high-quality printing in relatively simple structure and at high speed, and an image forming apparatus using it. The multi-beam scanning optical system has an incidence optical unit for guiding a plurality of beams emitted from a light source unit having a plurality of light-emitting regions spaced apart from each other in a main scanning direction, to a deflector; a scanning optical unit for focusing the plurality of beams deflected by the deflector, on a surface to be scanned; and a synchronism-detecting optical unit for converging part of the plurality of beams deflected by the deflector, via a return mirror on a slit surface by a lens section, thereafter guiding the beams to a synchronism detector, and controlling timing of a scan start position on the surface to be scanned, by use of a signal from the synchronism detector.

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: It is an object of this invention to provide an image input system, image input apparatus, and image input method which can greatly reduce the time before actual image reading is started, and which is easy to use in accordance with a power-saving standard. To achieve this object, an image input system having an image input apparatus whose image reading is controllable from an external apparatus includes a light source light amount controller for controlling a light source for illuminating an original, and a switch for designating the start of original image reading. When designation of the start of original image reading is detected, the light source light amount controller turns on the light source and starts light amount adjustment, and the start of the image input apparatus from the external apparatus is designated.

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 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: 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: 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: To obtain an optical scanning device in which timing of a scanning start position on a surface to be scanned (hereinafter referred to as object surface) is stabilized and detection precision of a synchronous signal by a synchronous position detecting unit is improved, with the result that an image with higher definition can be obtained.

Abstract: Information of oscillation frequency of a laser beam source in a predetermined range including usable oscillation frequency that takes into consideration an output quality of the laser beam source, such as information on a relationship between oscillation frequency and output quality, is stored in a memory. Then, when the laser beam source is controlled, based on the information stored in the memory, a particular frequency range where the output quality of the laser beam source deteriorates or becomes good is specified, and a decision is made whether or not oscillation frequency f, which is going be used, is within the particular frequency range. Then, according to the results, the oscillation frequency is set, avoiding a frequency range where the output quality deteriorates or within a frequency range where the output quality becomes good according to the result. Thus, a laser beam source whose output quality is always good can be used.

Abstract: Provided are a multi-beam scanning optical system capable of implementing high-quality printing in relatively simple structure and at high speed, and an image forming apparatus using it. The multi-beam scanning optical system has an incidence optical unit for guiding a plurality of beams emitted from a light source unit having a plurality of light-emitting regions spaced apart from each other in a main scanning direction, to a deflector; a scanning optical unit for focusing the plurality of beams deflected by the deflector, on a surface to be scanned; and a synchronism-detecting optical unit for converging part of the plurality of beams deflected by the deflector, via a return mirror on a slit surface by a lens section, thereafter guiding the beams to a synchronism detector, and controlling timing of a scan start position on the surface to be scanned, by use of a signal from the synchronism detector.

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: A method of printing with an electrophotographic machine includes providing a first optical sensor for sensing a start-of-scan position of a laser beam produced by a scanning laser printhead and transmitting a first position signal indicative thereof A second optical sensor senses an end-of-scan position of the laser beam produced by the scanning laser printhead and transmits a second position signal indicative thereof A temperature of the scanning laser printhead is measured with a temperature sensing device. A plurality of positions of each of the first optical sensor and the second optical sensor are empirically determined at each of a plurality of values of the temperature of the scanning laser beam printhead.

Abstract: An optical writing head is provided in which the deviation of a line of light spots on the photosensitive drum in a sub-scanning direction due to manufacturing dispersion of a rod-lens array is corrected. In the optical writing head comprising a self-scanning light-emitting element array and a rod-lens array for projecting light emitted from the self-scanning light-emitting element array onto the photosensitive drum, the timing of a start pulse supplied to the start pulse line every chip is regulated to correct the deviation of the line of light spots.

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: An image forming apparatus maintains a constant beam scanning state so that light beams scan each drum always in the same state once a desired color overlapping accuracy is obtained by controlling color registration in color image formation. This mechanism achieves constantly fine color overlapping without forming a test pattern several times or consuming toner unnecessarily. A beam passage switch is provided in a laser scanning system. Sensors provided near each photosensitive drum determine whether each light beam has scanned a certain portion with no inclination or a certain scanning area, or whether each image magnification provides a desired size.

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: Even when reset during standby, an optical scanning apparatus according to the present invention enables the angles of mirror faces of galvanomirrors to be easily adjusted to reduce the time required to adjust the positions of light beams.

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: 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 light source, a light beam controlling mechanism, a sensor, and a signal controller. The light source emits parallel light beams with an angle smaller than 90° relative to a sub-scanning direction. The light beam controlling mechanism controls a scanning of the light beams. The sensor detects one of the light beams and generates a line synchronous signal. The signal controller delays the data streams and generates PLL clock signals divided into different clock signals having a same frequency and having phases sequentially varied. The signal controller selects one of the different clock signals and drives the light source with the selected clock signal.

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: The emission level of a laser source at the non-imaging time when image data “0” is input and the emission level at the imaging time when image data “1” is input are controlled so that each of them becomes a desired level. The light output intensity is stabilized at all times regardless of variations in ambient temperature. As a result, images uniform in density can be obtained.

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: 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: Provided are a multi-beam scanning optical system capable of implementing high-quality printing in relatively simple structure and at high speed, and an image forming apparatus using it. The multi-beam scanning optical system has an incidence optical unit for guiding a plurality of beams emitted from a light source unit having a plurality of light-emitting regions spaced apart from each other in a main scanning direction, to a deflector; a scanning optical unit for focusing the plurality of beams deflected by the deflector, on a surface to be scanned; and a synchronism-detecting optical unit for converging part of the plurality of beams deflected by the deflector, via a return mirror on a slit surface by a lens section, thereafter guiding the beams to a synchronism detector, and controlling timing of a scan start position on the surface to be scanned, by use of a signal from the synchronism detector.

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: An image forming device in which a plurality of image frames are exposed onto a photosensitive material at an exposure device, and the photosensitive material is superposed with image receiving materials of same sizes as the image frames on a heat drum, such that a plurality of image frames can be heat transferred all at once onto the image receiving materials. Image receiving materials of different sizes are readied in a plurality of magazines, and an image receiving material (magazine) of an appropriate size is selected in accordance with an exposure pattern and sizes of the image frames. Various types of prints can be formed by merely setting one photosensitive material. Further, because the plurality of image frames are heat transferred onto the image receiving materials all at once, printing processing efficiency can be improved.