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: 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: A reference voltage generation circuit includes a first current-mirror circuit including a first MOS transistor connected to a first power source and a second MOS transistor of the first conductive type connected to the first power source; a second current-mirror circuit including a third MOS transistor and a fourth MOS transistor; a first resistor connected to the first node; a first bipolar transistor having a collector connected to the first resistor, an emitter connected to a second power source, and a base connected to the first node; a second bipolar transistor having a collector connected to the second node, an emitter connected to the second power source, and a base connected to the first bipolar transistor; a fifth MOS transistor connected between the first power source and an output terminal; and a third resistor connected between the output terminal and the second power source.

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: 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: 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: A disclosed device printer apparatus includes a recording sheet conveying block holding a recording sheet and including a light emitting element, and a first light receiving element; a head block printing characters, graphics or the like on the recording sheet including a second light receiving element positioned to face the light emitting element so as to directly receive the light; and a control circuit connected to the light emitting element, the first light receiving element, and the second light receiving element, wherein the control circuit determines, when the light is detected by the second light receiving element, that the recording sheet does not exist between the light emitting element and the second light receiving element, and when the light is not detected by the second light receiving element and is detected by the first light receiving element, that the recording sheet exists.

Abstract: An image forming apparatus to form an image by optical scanning includes a light emitter to emit a light beam; a rotary reflective mirror to reflect the light beam; a photoreceptor to receive the light beam reflected by the rotary reflective mirror to form a latent image; a light sensor to detect the light beam; and an optical scanning controller to control scanning of the light beam. In such an image forming apparatus, the optical scanning controller causes the light emitter to emit the light beam when the light beam does not expose an area of the photoreceptor where a latent image is formed and adjusts a power of the light beam in discrete increments to a predetermined level appropriate for optical scanning.

Abstract: An optical scanning device is disclosed that includes a light source unit, a light source drive unit, a deflection unit, a scanning image optical system, and a light beam detection unit. In the optical scanning device, the light source drive unit controls an amount of light emission of the light source unit, and a light emission amount control period in which the light source unit is forcibly turned OFF is set to the light source drive unit during a period from when the deflection unit deflects to an edge of a scanning angle for scanning the main scanning area to when the deflection unit deflects to a maximum deflection angle of the deflection unit within a non-image forming period.

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: 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: 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: 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: The present invention provides an image processing method which includes at least any one of image recording and image erasing, wherein a light irradiation intensity at a center position of the laser beam irradiated in the image recording is controlled; in the image recording, a first auxiliary line extended by a predetermined distance from a start point of each of image lines constituting an image in the opposite direction from the scanning direction and a second auxiliary line extended by a predetermined distance from an end point of each of the image lines in the scanning direction are prepared, and when the first and second auxiliary lines including an image line are continuously scanned, the image line is scanned with irradiating the laser beam, and the first and the second auxiliary lines are scanned without irradiating the laser beam to thereby record the image.

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 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: 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.

Abstract: A beam light scanning apparatus capable of reducing influences of variations in characteristics of circuits disposed in a signal path extending until a laser driver and speeding up image data transfer for scan and exposure. Data of each line is distributed by an image data I/F into data trains of two channels, i.e., an odd-numbered pixel train and an even-numbered pixel train. The data in the two-channel trains are written by writing units into a plurality of memories in parallel for each of the trains in response to a line sync signal. During the same processing cycle as that for the writing, the data are read out of the memories in parallel by reading units. The data of two channels are combined by a multiplexer into a data train in the original order of pixels in each line, and a driving signal based on the combined data is generated by a PWM. A laser is driven by the driving signal.

Abstract: An image forming apparatus includes a light source that emits a laser beam, a separating unit that separates the laser beam emitted from the light source into a first laser beam, and a second laser beam. a first photoelectric converting unit, a second photoelectric converting unit, and a control unit that executes a first light-intensity correction for correcting the light intensity of the second laser beam per scan by each scanning line, and a second light-intensity correction for adjusting a performance in forming the image data based on a current correction value for correcting a light intensity of the laser beam based on a first voltage and a second voltage and a drive current preliminarily-set with respect to the laser beam to cause the light source to emit the laser beam.

Abstract: An electro-optical device includes a potential generating circuit that generates a first power supply potential and a second power supply potential that is different from the first power supply potential; a first signal processing circuit that selectively outputs one of a first high potential and a first low potential according to a data signal at one of at least three levels; a second signal processing circuit that selectively outputs one of a second high potential that is different from the first high potential and a second low potential that is different from the first low potential according to the data signal; a first current source that generates a first current in accordance with an output of the first signal processing circuit and the first power supply potential; a second current source that generates a second current in accordance with an output of the second signal processing circuit and the second power supply potential; and an electro-optical element that provides a tone level according to the fi

Abstract: A scanning optical apparatus includes, for example, a light source that outputs a light beam that has been pulse width modulated in accordance with input image data and a deflection unit that deflects the light beam so that the light beam scans the surface of an image carrier in the main scanning direction. The scanning optical apparatus furthermore includes a correction unit that corrects the pulse width and light amount applied to the light beam at each scanning position in the main scanning direction on the image carrier in accordance with focus error in the light beam at each scanning position.

Abstract: The present invention relates to a system for optically adjusting a computer-to-plate (CTP) imaging head which includes an a light source (104), optical fiber (124) for transmitting light emitted from the light source; an imaging lens (204) for focusing light emitted from a distal end of the optical fiber (128) on a substrate; wherein a portion of light striking the substrate is reflected back to the distal end of the optical fiber; a fiber optic coupler (116) in the optical fiber which transmits the reflected light to a light detector (112); wherein the light detector measures intensity of the reflected light; and a control unit configured to adjust the imaging head according to the intensity of the reflected light.

Abstract: A method of compensating for a light amount drift of a photosensor used in an image control device, wherein the photosensor includes a light emitting portion and a light receiving portion which projects light onto an image control mark formed on an intermediate transfer medium of a printer and detects an optical signal reflected by the image control mark, thereby controlling the quality of an image. In the compensation method, the light amount drift is calculated by projecting light on the intermediate transfer medium, detecting an amount of light reflected by the intermediate transfer medium, and comparing the detected light amount with a pre-set reference light amount. The detected light amount is then corrected to be substantially equal to the reference light amount.

Abstract: An image processing method including calculating a density of a character to be recorded based on information of a type, size and line width of the character; adjusting an irradiation energy of a laser beam for recording the character based on the density of the character; and irradiating a recording medium with the laser beam whose irradiation energy is adjusted so as to record the character thereon.

Abstract: In an image forming apparatus, a separating unit separates each laser beam into a first laser beam used for measuring light intensity and a second laser beam used for scanning a photosensitive element, a photoelectric converting unit measures a light intensity of each of the first laser beams and outputs a voltage indicative of the light intensity. A control unit controls a light intensity of each of the laser beams based on a common drive current and a corresponding one of a current correction value, which is set by each of the laser beams to correct a light intensity of a corresponding one of the laser beams based on a corresponding one of the voltages output by the photoelectric converting unit.

Abstract: A light-amount detecting device includes: a light source which emits a light beam; a branching optical element which divides the light beam emitted from the light source into a first light beam traveling in a predetermined direction and a second light beam traveling in a direction different to the predetermined direction; a light-condensing element which condenses the second light beam; a light-receiving element having a light-receiving surface which receives the second light beam condensed by the light-condensing element; and a detector which detects a light-amount of the second light beam received by the light-receiving element, and at least one of a direction of reflected light of the second light beam reflected from the light-receiving surface of the light-receiving element and spread of the reflected light of the second light beam reflected from the light-receiving surface of the light-receiving element is adjusted to control a light-amount of the reflected light of the second light beam returning to the

Abstract: An optical scanning apparatus includes a light source and a structure for performing light-power control for the light source, the structure including a light-power-detection optical unit that establishes an optically conjugate relationship between a deflecting surface of a deflecting unit and a light-receiving surface of a light-power detector in a main-scanning plane. Accordingly, the storage time of a light beam on the light-power-detection optical unit is increased and variation in the power of light emitted by the light source due to heat generated by the light source and environmental variation is accurately detected.

Abstract: Apparatuses and methods are provided for processing a substrate having an upper surface that includes a central region, a peripheral region, and an edge adjacent to the peripheral region. An image having an intensity sufficient to effect thermal processing of the substrate is scanned across the upper surface of the substrate. The image scanning geometry allows processing the central region of the substrate at a substantially uniform temperature without damaging the outer edge. In some instances, the image may be formed from a beam traveling over at least a portion of the central region so that no portion thereof directly illuminates any portion of the edge when the image is scanned across the periphery region. The substrate may be rotated 180° or the beam direction may be switched after part of the scanning operation has been completed.

Abstract: A semiconductor laser driver to drive at least one semiconductor laser, the semiconductor laser including a storage device, an emission-intensity setting device, and a drive circuit. The storage device stores emission-intensity switching data to control light-emission intensity of the semiconductor laser, the emission-intensity setting device sets the light-emission intensity based on the emission-intensity switching data stored in the storage device, and, the drive circuit generates a driving current to drive the semiconductor laser based on the light-emission intensity set in the emission-intensity setting device.

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 an image forming apparatus equipped with an exposure section including a plurality of LED elements, the apparatus forming an electrostatic latent image on a photosensitive body with the exposure section, the apparatus including: an RFID tag provided in the exposure section, the RFID tag including a light quantity correction data storing section and a communication section to perform wireless communication; an RFID reader/writer to perform the wireless communication with the RFID tag; a control section to allow the RFID reader/writer to perform the wireless communication with the RFID tag so as to read or write the light quantity correction data from/to the light quantity correction data storing section of the RFID tag during a period when no processing related to the image data is being performed; and a storage section to store the read light quantity correction data.

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: Disclosed is an evaluation device of an optical writing device, comprising: the optical writing device; a light reception section; a drive section; and a control section to light each light emitting element in a previously set lighting pattern based on a light amount; to drive the drive section to move the light reception section to a position opposite to the light emitting element to be lit; to calculate characteristic data based on a light amount value of the light received by the light reception section; to calculate a first calculation value based on the characteristic data for each light emitting element; to calculate a second calculation value different from the first calculation value based on the characteristic data; to calculate a third calculation value based on the first calculation value and the second calculation value; and to instruct the display section to display the third calculation value.

Abstract: In a light source device including an aperture member that regulates a light beam, |(Pap1?Pap2)/Pap2|<|(P1?P2)/P2| is satisfied where P2 is a light intensity of the light beam entering the aperture member at a time t2 when 2 microseconds have passed since current was applied to the laser, P1 is a light intensity of the light beam entering the aperture member at a time t1 when 40 nanoseconds have passed since a light intensity of the light beam entering the aperture member reached 0.1 time the light intensity P2, Pap2 is a light intensity of the light beam output from the aperture member at the time t2, and Pap1 is a light intensity of the light beam output from the aperture member at a time t1? when 40 nanoseconds have passed since a light intensity of the light beam output from the aperture member reached 0.1 time the light intensity Pap2.

Abstract: A light-emitting device includes: light-emitting elements whose luminous energy is controlled according to a current value and a pulse width of a driving signal; a storage unit that stores first and second coefficients for every light-emitting element; a pulse width determining unit that determines the pulse width of the driving signal supplied to each light-emitting element on the basis of the first coefficient, a current value determining unit that determines a current value of the driving signal supplied to each light-emitting element on the basis of the second coefficient, a driving unit that supplies the driving signal having the current value determined by the current value determining unit within the determined pulse width determined, to the light-emitting element, and a coefficient determining unit that calculates the first coefficient based on target values of a light amount and first peak light amounts of one of the light-emitting elements, and calculates the second coefficient.

Abstract: A method of compensating for a light amount drift of a photosensor used in an image control device, wherein the photosensor includes a light emitting portion and a light receiving portion which projects light onto an image control mark formed on an intermediate transfer medium of a printer and detects an optical signal reflected by the image control mark, thereby controlling the quality of an image. In the compensation method, the light amount drift is calculated by projecting light on the intermediate transfer medium, detecting an amount of light reflected by the intermediate transfer medium, and comparing the detected light amount with a pre-set reference light amount. The detected light amount is then corrected to be substantially equal to the reference light amount.

Abstract: An image forming apparatus includes an optical scanning device that scans a scan area on an image carrier with light flux containing image information and writes the image information onto an image area in the scan area. In the optical scanning device, a first light receiving unit receives light flux emitted from a light source and reflected by a reflecting optical unit; a second light receiving unit receives light flux that passes through an aperture of the reflecting optical unit, is deflected by a deflecting unit, and heads for outside the image area within the scan area; and a control unit controls a drive signal of the light source based on signals output from the first and second light receiving units.

Abstract: The invention relates to a method for establishing a light beam (CLB) with substantially constant luminous intensity comprising the steps of establishing a light beam (LB) by means of a light source (SAL) and controlling an attenuation of said light beam (LB) on the basis of occurrences of luminous intensity peaks (IP) in said light beam (LB).

Abstract: In an exposure device comprising a laser controller that is configured as a circuit board capable of independently being changed, and that controls the emission of laser light from a laser emitter emitting laser light on receipt of an instruction for control given from a main controller responsible for overall control of the operation of the exposure device, error control information that is obtained in advance with regard to the circuit board and controls variations of a controlling factor due to a circuit error of the circuit board is stored into a memory provided to the laser controller prior to the provision of the circuit board to the exposure device. On receipt of an instruction for control given from the main controller to cause the emission of laser light in a predetermined amount of light, the laser controller determines a condition of emission of laser light based on the error control information stored in the memory to cause the laser emitter to emit laser light under the condition of emission.

Abstract: At least one light emission array includes a plurality of light emitting elements arrayed in a first direction. Each of the light emitting elements is an organic electroluminescence element. A monitor quantitatively monitors a light emitting state of at least one of the light emitting elements to obtain a monitored amount. A comparator compares the monitored amount and a reference amount. A controller performs a constant current control with respect to at least one of the light emitting elements in accordance with a result of the comparison performed by the comparator.

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: 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.