Abstract: A visible laser beam scanned by a galvano-scanner system is aligned at each of positioning points on the top surface of a master work by manual operation to record sensor position signals of position sensors on galvano-scanners. The sensor position signals on each positioning point are recorded to create a drive pattern in accordance with recorded sensor position signals. The drive pattern no longer has optics system error sources including focus error and attachment error as well as errors caused by scale, offset and the like, also eliminating the need for entering a distance as far as the top surface of the work. Therefore, the drive pattern with error components removed can be created with ease.

Abstract: An image forming device includes a photoreceptor drum including a target surface that is scanned in a main scanning direction and a sub-scanning direction, an exposure head including a plurality of light emitting segments aligned in parallel to the main scanning direction, an exposure driving unit which selectively drives the plural light emitting segments, a storing unit which stores a profile where the respective positions of the plural light emitting segments correspond to a correction amount from the main scanning direction toward the sub-scanning direction at every position, and a correcting unit which smoothes a local change of the correction amount in the profile.

Abstract: An image forming apparatus having: a light source for emitting a beam; a deflector for deflecting the beam; a light receiving element for receiving the beam and generating a detection signal; a converter for converting electric potentials of the detection signal into data values and generating time data associated with the data values; and a first calculator for calculating a position of center of the beam from the data values and the time data.

Abstract: An image forming apparatus includes a photosensitive body, an exposure unit, a pulse generating unit, a smoothing unit, a drive current generating unit, and a second emitting control unit. The exposure unit includes a light source for emitting a light beam, and causes the light beam emitted from the light source to perform scanning in a main scanning direction, thereby drawing a main scanning line on the photosensitive body. The second emitting control unit causes the light source to emit the light beam, in an APC period of automatically controlling the light quantity of the light beam, by causing the pulse generating unit to generate a pulse signal having a duty ratio of 100 percent, causing the smoothing unit to smooth the pulse signal thereby generating an analog signal, and causing the drive current generating unit to generate a drive current based on the analog signal.

Abstract: An optical scanning apparatus that is capable of increasing use life of a semiconductor laser by decreasing the emission time for sensors that are independently provided for synchronous control, light control, and focus control. A laser beam emitted from a light source is deflected by a deflector, and scans a photoconductor. A beam splitter arranged between the light source and the deflector separates the laser beam, which is detected by a first detection unit. A second detection unit arranged in a non-image forming area detects the deflected laser beam to detect defocus amount. A focusing unit focuses the scanning laser beam based on a detection result of the second detection unit. A control unit controls the light amount of the laser beam applied to an image forming area based on a detection result of the first detection unit at the timing when the second detection unit detects the laser beam.

Abstract: An optical writing device includes a light emission control unit configured to cause a light source to emit light based on a rotational position of a photosensitive element and pixel information making up a correction pattern to form an electrostatic latent image of the correction pattern on the photosensitive element, the correction pattern being formed across an entire circumference of the photosensitive element in a rotating direction; a reading signal acquiring unit configured to acquire reading signals resulting from reading the correction pattern, and generate, based on the reading signals, density variation information in which the rotational position and a density of the correction pattern are associated; and a correction value information generation control unit configured to generate information about correction to an amount of light emitted by the light source based on the density of the correction pattern to generate correction value information.

Abstract: A light source includes a plurality of light-emitting units arranged in a two-dimensional array. An optical element changes divergence angles of laser beams from the light-emitting units. A splitting element splits a part of each of the laser beams passing through the optical element. A compensating element compensates for a fluctuation in the divergence angle of each of the laser beams incident on the splitting element due to a change of temperature. A light-receiving element receives laser beams split by the splitting element. The light source, the optical element, the splitting element, the compensating element, and the light-receiving element are integrally supported.

Abstract: Since a photodiode (PD) is disposed in the vicinity of the plurality of light emitting elements and, therefore, the PD also receives a laser beam emitted only by a bias current during the APC period, setting a bias current based on a result of light amount detection by the PD does not result in a bias current setting with sufficient accuracy. To solve this issue, an electrophotographic image forming apparatus forms an electrostatic latent image pattern on a photosensitive drum, and controls the value of the bias current set for a first light emitting element based on the potential of the electrostatic latent image pattern and a detecting result of the PD.

Abstract: An optical device includes: an irradiation unit that irradiates a part of laser beams output from a light source as a scan beam onto an irradiation target and outputs the remaining part of the laser beams as a monitor beam used to monitor a light amount of the laser beams; a measurement unit that measures a light amount of the monitor beam; a storage unit that stores a plurality of measurement results obtained by the measurement unit when the laser beams are output in a plurality of different light amounts, and the plurality of the different light amounts associated with each other; and a prediction unit that predicts the light amount of the monitor beam relative to a reference light amount of the laser beam using a plurality of the light amounts stored in the storage unit and the measurement results corresponding to the plurality of the light amounts.

Abstract: First and second light amount detection elements are arranged on a scanning line of a laser beam. The first light amount detection element receives a laser beam having a first light amount, and the second light amount detection element receives a laser beam having a second light amount that is lower than the first light amount. The detection signal that is output by the second light amount detection element is amplified by an amplifier and used as a synchronization signal. Here, an amplification factor of this amplifier is greater than an amplification factor of another amplifier for amplifying the detection signal that is output by the first light amount detection element. The detection signals amplified by the amplifiers are modified by a modification coefficient that correspond to the amplification factors, and used as signals that indicate the light amounts.

Abstract: A light source control apparatus that do not always require calculations for the upper limit of driving current when characteristic of a light source varies. The light source control apparatus controls a light source that exhibits a characteristic including an uptrend region where the light amount increases with increasing driving current and a downtrend region where the light amount decreases with increasing driving current. A determination unit determines whether the light source is in the uptrend or downtrend region based on signals from a light variation detection unit and a current variation detection unit. A control unit matches the light amount (L) with target light amount (T), by increasing the driving current when L<T in the uptrend region or when L>T in the downtrend region, and by decreasing the driving current when L>T in the uptrend region and when L<T in the downtrend region.

Abstract: An optical device includes a drive unit configured to drive a light source that outputs a laser beam; a detecting unit configured to detect the laser beam output from the light source; a converting unit configured to convert an output of the detecting unit into a value within a predetermined range; and a control unit configured to control the drive unit to switch a light quantity of the laser beam output from the light source from a first light quantity within an imaging light quantity range for forming an image to a second light quantity outside the imaging light quantity range, or vice versa. The converting unit converts an upper limit light quantity in the imaging light quantity range into a maximum value in the predetermined range, and converts a lower limit light quantity in the imaging light quantity range into a minimum value in the predetermined range.

Abstract: An image forming device includes: an exposure head that includes a light emitting element and a light emission controller that causes the light emitting element to emit light on the basis of a control signal; a photoreceptor that is exposed to the light emitted by the light emitting element included in the exposure head so that a latent image is formed on the photoreceptor; a correcting section that corrects the control signal on the basis of the spectral sensitivity of the photoreceptor to a spectral distribution of the light emitting element; and a developing section that develops the latent image formed on the photoreceptor.

Abstract: Apparatus that forms an image according to image information includes density sensors that detect image density variations in main and sub-scanning directions. A processing device generates correction data for correcting a light source output to suppress the density variations based on detection results. The processing device modifies the correction data such that the light source output after the correction is at least a minimum rated output at a position at which the output after the correction is lower than the minimum rated output, in the relation between a position on the surface of the photosensitive element in the main-scanning direction and the output after the correction, and modifies the correction data such that the light source output after the correction is at most a maximum rated output at a position at which the output after the correction is higher than the maximum rated output.

Abstract: An image processing method including: measuring a distance between a medium where an image is to be recorded and an image processing apparatus which stores a relation between irradiation energy and distance previously measured; calculating an irradiation energy from the distance measured in the measuring based on the relation stored in the image processing apparatus; and irradiating and heating the medium with laser beams having the irradiation energy obtained in the calculating to record an image in the medium.

Abstract: An image forming apparatus that generates a synchronization signal without breaking laser diodes (LDs). The LDs output beams, which in turn are deflected to scan a photosensitive member. The synchronization signal is generated upon detecting the deflected beams. The LDs output the beams so as to generate the synchronization signal, based on which the output timing of the beams from the LDs is controlled. It is possible to select a first mode in which at least two of the LDs output the beams so as to generate the synchronization signal, and a second mode in which one of the LDs output the beams so as to generate the synchronization signal. The value of drive current supplied to at least two of the LDs when the first mode is selected is smaller than the value of drive current supplied to one of the LDs when the second mode is selected.

Abstract: An image forming apparatus including: a light scanning portion that lights a plurality of beams, and scans a surface to be scanned of an image carrier to form an electrostatic latent image; a detection portion that detects at least one lighted beam; an abnormality detection portion that transmits data to the light scanning portion via a transmission-line, causes the light scanning portion to light a beam, and detects abnormality of the transmission-line based on the detected beam; and a setting portion that sets a number of beams to be lighted in the case of the formation of the electrostatic latent image so that an amount of light of the detected beam in the case of abnormality detection of the transmission-line is equal to or more than a minimum amount of light of the detected beam in the case of the formation of the electrostatic latent image.

Abstract: An optical scanning apparatus controls an output of a light source for forming an electrostatic latent image on an image carrier. The optical scanning apparatus includes a correction amount control unit configured to variably control a light quantity correction amount of the light source according to a scanning position on the image carrier during one scanning operation with a beam generated from the light source, an output signal level changing unit configured to change a level of an output signal from the correction amount control unit, and a light quantity control unit configured to control a light quantity of the light source according to the scanning position based on a signal from the output signal level changing unit.

Abstract: An electrophotographic image forming apparatus performs latent image rendering using a plurality of light sources. The electrophotographic image forming apparatus includes a rendering time control unit that controls a latent image rendering start time for each of the light sources, a scanning time control unit that controls a scanning start time for each of the light sources, a pattern forming unit that forms a pixel pattern corresponding to pixel pattern data defined in advance on a photosensitive member, and a density detection unit that detects a density of the pixel pattern formed on the photosensitive member. The rendering time control unit and the scanning time control unit respectively control the rendering start time and the scanning start time for each of the light sources using a density value detected by the density detection unit.

Abstract: An image forming apparatus, which forms an image by forming an electrostatic latent image on a photosensitive member with a laser beam, developing the electrostatic latent image with a developer to obtain a developer image, and transferring the developer image to a sheet, includes a light source which outputs the laser beam for exposing the photosensitive member; a PLL circuit which generates a multiplied clock that is obtained by multiplying a reference clock; a pulse-width modulating circuit which outputs a pulse-width-modulated signal based on image data and the multiplied clock in order to drive the light source; and a CPU which obtains image data to be input to the pulse-width modulating circuit and, when it is unnecessary to output the pulse-width-modulated signal based on the obtained image data, controls the PLL circuit so as not to generate the multiplied clock.

Abstract: Disclosed is an image forming apparatus including an optical writing device including, a light source section composed of a plurality of light emitting elements arranged in a main scanning direction; an optical section including a plurality of coupled lenses to form an image on a light exposure face by gathering light emitted from the light emitting elements; and a storage section to store first correction data for correcting the light intensity of the plurality of light emitting elements and second correction data for correcting an optical characteristic specific to the coupled lens, and a control section to read out the first correction data and the second correction data from the storage section of the optical writing device and to correct the first correction data based on the second correction data.

Abstract: An image forming apparatus that performs a shading correction includes a light source that emits a light beam; a light-source drive unit that drives the light source; and a light-quantity-adjustment-amount control unit that performs an adjustment of a light quantity in accordance with a shading correction curve by controlling, for the light-source drive unit, a light-quantity adjustment amount and an increase/decrease cycle of the light-quantity adjustment amount. The increase/decrease cycle is a unit of time within a time period during which the light-quantity adjustment amount increases or, decreases.

Abstract: A deflector deflects a light beam emitted from a light source including a plurality of light-emitting units. A scanning optical system focuses the light beam deflected by the deflector on a scanning target surface. A monitoring photoreceiver receives a part of a light beam deflected by the deflector and directed toward an area within a scanning area outside an image area. A detecting unit individually detects emission powers of at least two light-emitting units based on an output signal of the monitoring photoreceiver in a single sweep of scanning.

Abstract: An exposure device configured to perform exposure using a plurality of light beams and capable of stabilizing image density without increasing circuit size. The exposure device has a first light source for emitting a first light beam and a second light source for emitting a second light beam. The exposure device exposes a photosensitive drum such that areas exposed to the respective first and second light beams at least partially overlap each other. A first drive current having a predetermined value and a second drive current are supplied to the respective first and second light sources. A photodiode detects the intensities of the respective first and second light beams or the sum of the intensities. The second drive current is controlled based on a detection result from the photodiode such that the sum of the intensities becomes equal to a target intensity.

Abstract: An exposure device includes light emitting elements, a driving circuit, an image-signal connector, a power connector, and an adjustment-control-signal connector. The light emitting elements emit light which an exposure target member is exposed to. The driving circuit performs one of first and second drive operations. The image-signal connector has terminals connected to core wires of an image-signal cable, and relays, to the driving circuit, image signals transmitted through the image-signal cable. In the image-signal cable, the core wires are arranged at a first pitch. The power connector has terminals arranged at a pitch wider than the first pitch, and relays, to the driving circuit, power transmitted through power cables. The adjustment-control-signal connector has terminals arranged at a pitch wider than the first pitch, and relays, to the driving circuit, light-amount adjustment control signals transmitted through adjustment-control-signal cables.

Abstract: A light stabilizer used for an electronic device including a plurality of electronic parts including a light source, a main power source for supplying a drive current to the electronic parts, and a start button for the light source, wherein the light stabilizer comprises, a heating power source that supplies a heating current to the light source to make the light source self-heat in a non-light emitting state, and a control section that executes control so that after the main power source is turned on, the heating current is supplied to the light source firstly out of the plurality of electronic parts to increase temperature of the light source to the degree higher than dew point temperature, and when the start button is pressed down, the drive current is supplied to make the light source emit light.

Abstract: Systems and methods for providing laser texturing of solid substrates are disclosed. The texturing may be used to provide grayscale images obtainable from substrates, which may include steel, aluminum, glass, and silicon. In some embodiments, images may be obtainable from the substrate by modifying the reflective, diffractive, and/or absorptive features of the substrate or the substrate surface by forming random, periodic, and/or semi-periodic micro-structure features on the substrate (or substrate surface) by an ultrafast laser pulse train. The ultrafast pulse train may be modulated in order to vary, for example, optical exposure time, pulse train intensity, laser polarization, laser wavelength, or a combination of the aforementioned. The ultrafast pulse train and the substrate may be scanned with respect to each other to provide different optical energies to different regions of the substrate (or substrate surface).

Abstract: A method of calibrating an electrophotographic printer (30), the printer configured with a plurality of light settings, each light setting arranged to produce a different element type, the method comprising: determining (S10) a first light level required to print a first element type by applying a proportional change to a first initial light setting; and determining (S30) a second light level required to print a second element type by applying substantially the same proportional change to a second initial light setting.

Abstract: An apparatus for switching and controlling the intensity of a laser beam directed toward a beam detect sensor for an image forming device. A printing power reference signal and a beam detect power reference signal is selectively connected to a laser driver through a first switch. A printing power reference holding capacitor and a beam detect power reference holding capacitor is selectively connected to the laser driver through a second switch that is controlled in tandem with the first switch. During each scan cycle, the output laser power is monitored and used to adjust one of the two holding capacitors based such that both the printing power and the beam detect power have a controlled reference.

Abstract: Disclosed are an image forming apparatus capable of correcting a color registration error and a method for correcting the color registration error. The image forming apparatus can include an image receptor, a light scanning unit having a plurality of light sources and one or more beam deflectors, a developing unit, a transfer unit, and a color registration error correction unit configured to generate data about a color registration error based on a change in a light output value of the plurality of light source and to correct the color registration error between visible images formed on the image receptor.

Abstract: An optical writing device includes a light source that emits multiple laser beams; a separating unit that separates each of the multiple laser beams into a monitor beam and a scanning beam; a photoelectric converting element 218 that outputs a monitor voltage depending on a quantity of the monitor beam; a memory that stores an initial correction value for correcting a set common current; and a microcontroller that calculates a reference current, which is produced by correcting the common current updated on the basis of the monitor voltages with the initial correction values, obtains corrected currents by correcting the common current with the calculated correction values, controls each quantity of the laser beam on the basis of the corrected currents, and determines that the light source is degraded if a ratio of the corrected current to the reference current is larger than a predetermined threshold value.

Abstract: A light output device comprises a controller configured to generate a set signal that sets a reference voltage for determining a predetermined value of an output power of the light in a case of power adjustment wherein the output power is changed to a power different from in a case of power accuracy requirement, and a reference voltage generating section configured to generate the reference voltage according to the set signal. The controller in the case of power accuracy requirement puts a set-signal output port in a high-impedance state, while in the case of power adjustment generates the set signal using a predetermined voltage, the set signal alternating between a high level and a low level. The reference voltage generating section in the case of power accuracy requirement generates the reference voltage on a basis of a level shift voltage generated by level shifting the predetermined voltage.

Abstract: The emission intensity of a laser beam source, at a time when a laser beam emitted from the laser beam source and scanned by an optical scanning device becomes incident to a laser beam detector provided in a predetermined position on the scanning path of the laser beam in order to hold a position of an electrostatic latent image formed on a photoreceptor constant in the main scanning direction, while at the same time, changing the emission intensity of the laser beam, is set so as to become the consistently same emission intensity regardless of a change in emission intensity at the time of electrostatic latent image formation onto a photoreceptor. This allows the detection timing of a laser beam by a laser beam detector to be kept constant.

Abstract: The image densities of images formed with a plurality of laser beams on the basis of image data are measured. The quantity of each of the plurality of laser beams is adjusted in accordance with the measurement result.

Abstract: An image forming apparatus includes a light source, a polygon mirror, and a plurality of photosensitive elements. The polygon mirror has a plurality of reflection surfaces that reflect a light beam at different angles. The light beams deflected by the reflection surfaces travel along different optical paths and impinge on different photosensitive elements. A light-beam control unit controls emission of the light beam from the light source depending on a distance between the deflecting unit and the photosensitive elements thereby performing an f? correction of the light beam.

Abstract: An optical write apparatus. The apparatus has a semiconductor laser drive apparatus that modulates a semiconductor laser according to a modulation signal and induces the semiconductor laser to emit light. The drive apparatus has a control unit that is adapted to supply a fixed bias current during a light emission off time, and start supplying a predetermined current that is less than a light emission threshold current right before a light emission time. The apparatus has a write unit that is adapted to realize optical writing on an image sustaining element by scanning a laser beam that is emitted from the semiconductor laser driven by the semiconductor laser drive apparatus using a polygon mirror.

Abstract: A method for adjusting a spatial light modulator comprising an array of channels, the method includes selecting a plurality of channel sets, wherein all the channels in each set are contiguously arranged; determining a first intensity value for first output radiation in the channel sets; performing a first adjustment based on the first intensity value, including adjusting a control level of a first channel in the first channel set without adjusting a control level of a second channel in the first one of the channel sets; determining a second intensity value for second output radiation, which includes output radiation by some of the channels in the first channel set, and excludes output radiation provided by at least one channel in the first channel set; and performing a second adjustment based at least on the second intensity value.

Abstract: It is determined whether a low density area in which pixels having density less than a predetermined density exist in succession is included in an image signal or not, and if the low density area exists, an image is formed by irradiating the laser light in a first condition for a pixel to be interested in each pixel area within the low density area and irradiating the laser light in a second condition being different from the first condition for other pixels in the pixel area. In this way, it is possible to improve reproducibility of a highlight area in a high resolution image and improve reproducibility of characters and line images or the like.

Abstract: A scanning optical device includes a deflector for scanningly deflecting a plurality of light beams from a plurality of light sources, and an imaging optical system for imaging the light beams upon a plurality of scan surfaces to be scanned, wherein at least one piece of reflecting element is provided at each of a plurality of light paths extending from the deflector toward the scan surfaces.

Abstract: An exposure device includes plural light-emitting elements, a light amount detection unit, a controller, plural holding units and a connection unit. The controller sequentially determines control values of the light-emitting elements based on comparison between the light amounts detected by the light amount detection unit and a predetermined reference value. The holding units are provided for the light-emitting elements, respectively. Each holding unit holds a control voltage of the controller. When the controller is to sequentially determine control values of a part of the plurality of light-emitting elements, the connection units connects the controller and the holding units corresponding to one or more light-emitting elements for which control values are determined earliest among the part of the plural light-emitting elements, before the controller determines the control values of the one or more light-emitting elements.

Abstract: Disclosed are an apparatus, optical scanning device, and a corresponding method of forming images on a photosensitive surface. The apparatus includes a laser raster output scanner (ROS) including laser emitters arranged to simultaneously scan a plurality of laser beams across a single scan line of the photosensitive surface in response to received image data corresponding to pixels in an image to be reproduced, and a controller individually controlling each of the laser emitters to selectively apply one of a plurality of power levels to each of the laser beams based on the image data for each of the pixels, wherein a total power applied by the laser beams for each pixel is determined by a sum of the power levels applied by each of the laser beams.

Abstract: An image forming apparatus includes a light source; a separating unit that separates a laser beam emitted from the light source into a first laser beam and a second laser beam; a first photoelectric converting unit that measures a light intensity of the first laser beam and outputs a first voltage depending on the light intensity of the first laser beam; a second photoelectric converting unit that measures a light intensity of the second laser beam, and outputs a second voltage depending on the light intensity of the second laser beam; and a control unit that executes a first light-intensity correction for correcting the light intensity of the second laser beam based on a current correction value and a drive current. The current correction value being a value used for correcting a light intensity of the laser beam based on the first voltage and the second voltage, and the drive current being a current preliminarily-set with respect to the laser beam to cause the light source to emit the laser beam.

Abstract: An electrophotographic image forming apparatus having an LED array with a plurality of light emitting elements aligned in a main-scanning direction and a convergent lens array for imaging light emitted from the light emitting elements on a photosensitive member. In order to correct density unevenness caused by positioning errors of the lens array, the light quantity emitted from each of the light emitting elements is adjusted such that the total difference from a target value will be closer to zero.

Abstract: A device including: a photoreceptor; an LED printbar; and a computer processor for: determining how long LEDs on the printbar are energized while the device is operated to generate an image output; determining that a first plurality of LEDs has been energized less than a second plurality of LEDs; energizing the first plurality of LEDs for a correction time period as the LEDs are aligned with an inter-document zone (IDZ); and de-energizing the second plurality of LEDs during the time period. Energizing the second plurality of LEDs is unrelated to energizing the LEDs for purposes of evaluating an image. The time period is concurrent with operation of the device to generate an image output.

Abstract: An apparatus includes an output voltage sensing unit, which senses an output voltage of a laser diode, which has been sampled during a power control period and transmits the sensed output voltage of the laser diode to an output voltage control unit; the output voltage control unit, which obtains an error voltage between a reference voltage and the sensed output voltage of the laser diode and generates a control voltage by proportionally integrating the error voltage; and an optical power compensation unit, which receives the control voltage and generates a compensated control voltage by compensating for an optical power deviation on the photosensitive drum during the printing period.

Abstract: In an optical scanning device including a vertical cavity surface emitting laser (VCSEL), an optical scanning device controls so as to satisfy P1<P100 and Wm>Ws, where P1 is light intensity obtained when a period of time corresponding to a minimum pixel unit (referred to as “T1”) has elapsed after start of illumination; P100 is light intensity obtained when a period of time 100 T1 has elapsed after the start of illumination; Wm is the static beam spot diameter in the main-scanning direction; and Ws is the static beam spot diameter in the sub-scanning direction.

Abstract: A first beam splitter splits each laser beam into a first beam and a second beam. A deflecting unit deflects a direction of the second beam. A second beam splitter splits the second beam into multiple split beams. A first photoelectric converting unit measures intensity of the first beam and outputs first voltage. A second photoelectric converting unit measures intensity of each split beam and outputs second voltage. A control unit updates a driving-current correction value using the first voltage and the second voltage, corrects a driving current, and controls intensity of the laser beam based on corrected driving current.

Abstract: An apparatus and a method of controlling a light level of a light beam irradiated by a light source are provided. The light source is caused to irradiate the light beam having a light level determined based on a light level correction value for a specific main scanning position. The light level correction value is calculated based on light level change information indicating the change in the light level correction value for the specific main scanning position changes with respect to an initial light level correction value or a preceding light level correction value.

Abstract: An exposure apparatus has a plurality of light emitting elements and a light quantity measuring circuit, sets a reference light quantity based on a plurality of emission quantities when the plurality of light emitting elements emit light in accordance with a specific gradation signal for a predetermined emission time, generates a plurality of corrected gradation signals by correcting the gradation signal based on the differences between the reference light quantity and the plurality of emission quantities so that the plurality of emission quantities of the plurality of light emitting elements become close to the reference light quantity, and corrects the emission time of the plurality of light emitting elements so that the plurality of emission quantities of the plurality of light emitting elements become close to the target reference light quantity set in accordance with image data.

Abstract: An image forming apparatus that includes: a laser beam source; plural photoconductive members corresponding to plural colors; a modulation drive unit for performing pulse width modulation for each of colors by an image clock having a cycle of a pixel length,; a single piece of polygon mirror whose reflection surfaces are disposed in a rotation direction thereof with a plurality of different inclination angles with colors; a beam detector that is disposed adjacent to the photoconductive member; and an image clock/data switching unit configured to generate the image clock of a frequency varying with the colors for making the same a color-based image magnification, and switch the image clocks generated for each of the colors in synchronization with a detection signal coming from the beam detector.