Abstract: A driver apparatus drives light emitting elements connected to a common terminal. A clock driver outputs first and second pulses to first and second output terminals, respectively, alternately. A differentiating circuit includes an inductor and a resistor, and differentiates the first and second pulses to produce first and second clocks, respectively. A data driver circuit outputs a data signal to the common terminal in response to an ON/OFF command signal. A scanning circuit starts to operate in response to a starting signal such that the cascaded sub scanning stages turn on in sequence one at a time. A sub scanning stage turns on in response to the second clock, outputting a drive signal to a corresponding one of the light emitting elements. The light emitting elements emit light only when the drive signal and the ON/OFF command signal are fed to the light emitting elements.

Abstract: An optical writing device forms an electrostatic latent image on a photosensitive element by a connected light source controlled by a light source control circuit that includes: a pixel data output unit; a pixel data correcting unit that corrects a skew between main scanning line of electrostatic latent image and photosensitive element and a local deviation of the electrostatic latent image on the main scanning line, and outputs pixel data; a pattern generating unit that outputs pixel data for forming a predetermined pattern in an electrostatic latent image; a first light source control unit for causing a first light source, that needs correction of the local deviation, to emit light; a second light source control unit for causing a second light source, that does not need correction of the local deviation, to emit light; and a switch that switches between a first transmission status and a second transmission status.

Abstract: When the cathode of a light emitting thyristor is at the low (L) level, voltage is applied between the anode and cathode of the light emitting thyristor. In addition, because the gate of each thyristor and the gate of each light emitting thyristor are connected to each other in a self scanning circuit 100, voltage is also applied between the gate and cathode of the thyristor. At this time, by selectively turning only the gate of the light emitting thyristor, which is instructed by the self scanning circuit to emit light, to the high (H) level, the light emitting thyristor that is instructed is turned on. In particular, because an output signal of a clock driving circuit is differentiated by an RL differential circuit to generate an undershoot or overshoot waveform, the number of output terminals of the clock driving circuit can be reduced.

Abstract: A light-emitting device includes: plural light-emitting chips each having plural light-emitting elements, and each being designated, as a control target for lighting up or not lighting up, by two to Q designation signals (Q is an integer of two or more); and a selection signal generating part that selectively transmits P selection signals (P is an integer of three or more where P>Q) as the designation signals to designate each of the plural light-emitting elements as the control target, the designation signals for each of the plural light-emitting chips including a combination of two to Q selection signals taken from the P selection signals.

Abstract: An optical writing unit includes a plurality of light emitting element arrays, a plurality of clock signal generators, and a plurality of light emitting element controllers. The plurality of light emitting element arrays includes a plurality of light emitting elements aligned in one direction to project light. The plurality of clock signal generators generates image data transfer clock signals having different frequencies. The plurality of light emitting element controllers outputs the image data transfer clock signals received from the plurality of the clock signal generators and image data signals to the plurality of the light emitting element arrays to light up the light emitting elements based on the image data signals. The optical writing unit performs optical writing using light projected from the light emitting element arrays and controlled by the light emitting element controller based on the image data signals.

Abstract: An image recording apparatus including a memory element and a processor for a specially programmed general purpose computer. The memory element stores correction data for a plurality of locations on a photoreceptor for the image recording apparatus. The processor is for: inducing a charge on the photoconductive layer; receiving image data including, for said each location in the plurality of locations, a first or second desired voltage level; calculating, using the correction and image data, respective desired output power levels for a LED printbar for the apparatus, aligned with the plurality of locations, to discharge each location to the one of the first or second desired charge level, the respective desired output power levels selected to compensate for variances of respective induced charge levels at the plurality of locations; and supplying respective power inputs to the plurality of LEDs to generate the respective desired output power levels.

Abstract: An image forming apparatus includes: a light source; a brushless motor including a stator and a rotor; a rotary polygon mirror rotated by the brushless motor to form scanning lines on a photosensitive member; an energization switching unit turning on/off energizations of the coils; a voltage detecting unit outputting a detection signal based on induced voltages generated in coils of the stator by rotation of the rotor; a motor controlling unit turning on/off of the energizations by the energization switching unit based on the detection signal; an electric component that operates during formation of the scanning lines; and a power supply controlling unit which, in a detecting period of the detection signal for starting a rotation control of the brushless motor, reduces an amount of electric power supplied to the electric component to less than in a period of the formation of scanning lines after the detecting period.

Abstract: An image forming apparatus includes: a light source that emits a light beam; a photosensitive member; a brushless motor including a stator where a plurality of coils are placed and a rotor where a plurality of magnets are placed; a rotary polygon mirror, which is rotated by the brushless motor, and which periodically deflects the light beam emitted from the light source to sequentially form scanning lines on the photosensitive member; an energization switching unit that turns on and off energizations of the coils; a voltage detecting unit that outputs a detection signal based on induced voltages that are generated in the coils by rotation of the rotor; and a control unit that controls turning on/off of the energizations by the energization switching unit based on the detection signal.

Abstract: A light emission control device images an electrostatic latent image on a photosensitive element by a plurality of light emitting elements corresponding to a line in a second direction perpendicular to a first direction which is a rotational direction the photosensitive element. The light emission control device includes: a detecting unit that detects a rotational position of the photosensitive element, in the first direction, corresponding to a line in the second direction; an acquiring unit that acquires a distance between the light emitting elements and the rotational position of the photosensitive element in the first direction detected by the detecting unit; and a control unit that controls light emission by the light emitting elements according to the distance acquired by the acquiring unit and corrects a fluctuation in a density of a visible image converted from the electrostatic latent image.

Abstract: A light emitting element array includes a plurality of light emitting elements each having a first terminal, a second terminal, and a third terminal. The light emitting elements are arranged next to each other to form a group. The first terminal receives a drive signal, the second terminal is connected to ground, and the third terminal has a threshold voltage or a threshold current controllable from outside so that the light emitting elements are driven in a time division way.

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 exposure device includes a mirror to reflect light used for exposure of an object, a holder to hold the mirror, an adhesive that bonds the mirror to the holder and elastically deforms, and an adjusting tool that pushes the mirror to change a direction of the mirror.

Abstract: A semiconductor laser driver to drive a semiconductor laser, the semiconductor laser includes a drive circuit to generate a drive current to cause the semiconductor laser to emit, and a current control circuit to cause the driving current to repeatedly increase and decrease in a predetermined cycle.

Abstract: A drive circuit is provided for supplying a drive current to drive a plurality of driven elements each having two main electrodes. The drive circuit includes a switch circuit for receiving a drive signal; and a constant current circuit connected to the switch circuit for adjusting the drive current at a constant level. The constant current circuit is formed of a depletion type MOS transistor.

Abstract: The invention provides an exposure apparatus having a configuration such that, when a single laser light source having a plurality of light-emitting points is driven by a plurality of laser control apparatuses, mutual monitoring of the control state of the respective laser control apparatuses is possible, thus reducing malfunctions due to the effects of noise, and also provides a method to control this exposure apparatus, and an image forming apparatus. To accomplish this, the exposure apparatus does not execute light amount control of the light source to be driven when the determination unit has determined that another driving unit is causing the light source to be driven to emit light, and executes the light amount control of the light source to be driven when the determination unit has determined that another driving unit is not causing the light source to be driven to emit light.

Abstract: An optical writing apparatus includes a light source device that includes a VCSEL having an alignment of at least two channels in a sub scanning direction configured to emit plural light beams in a block. A deflector deflects the plural light beams toward an image bearer that forms an image by changing a line speed of image formation. A control device decreases a number of light beams by turning off a prescribed same number of the channels symmetrically from the both ends of the alignment in accordance with the line speed.

Abstract: A light emitting apparatus includes a plurality of light emitting chips, a first wire, a second wire, a third wire, and a fourth wire. The plurality of light emitting chips each have a plurality of light emitting devices and are divided into a plurality of chip groups, the light emitting devices in each of the light emitting chips being divided into a plurality of device groups. The first wire transmits in common a transmission signal to the light emitting chips. The second wire transmits in common a first selection signal to a given chip group of the light emitting chips. The third wire transmits in common a second selection signal to a set of the device groups. The fourth wire transmits a turn-on control signal to each of the chip groups.

Abstract: A semiconductor device includes three-terminal light emitting element array provided on a substrate, which includes a plurality of three-terminal light emitting elements which are substantially linearly arranged. Each three-terminal light emitting elements includes a first, second and third terminals. The third terminal is used to control a current between the first and second terminals. A Lead-out wiring portion is connected to the plurality of three-terminal light emitting elements. The three-terminal light emitting element array includes a common layer provided between two or more three-terminal light emitting elements adjacent to each other. The common layer mutually connects the second terminals (or the third terminals) of the two or three three-terminal light emitting elements.

Abstract: A light emitting element array that can perform a time-division driving operation with a small number of driving ICs is provided. A light emitting element array chip (1) includes n switch thyristors (S) (wherein n is an integer equal to or greater than 2), n signal transmission lines (GH) connected to N-gate electrodes (d) of the switch thyristors (S) individually, a plurality of light emitting thyristors (T) having N-gate electrodes (b) connected to one of the n signal transmission lines (GH). Anodes (e) of selection thyristors (U) are connected to the N-gate electrodes (d) of the n switch thyristors (S), and N-gate electrodes (f) of the selection thyristors (U) are connected to a common selection signal transmission line (CSL).

Abstract: A method is provided to manufacture displays such as, for example, reflective displays, electrophoretic displays or liquid crystal displays. In one embodiment of the invention, a method is provided for aligning a patterned layer of color filter elements with a display assembly. The method includes activating a first set of addressable pixel elements to change an activation state of each pixel element in the first set of the pixel elements. A required alignment of the patterned layer of color filter elements with the display assembly can be determined based at least on the activated first or a second set of the pixel elements. The patterned layer of color filter elements is aligned with the display assembly according to the required alignment.

Abstract: An optical writing device forms an electrostatic latent image on a photosensitive element by a connected light source controlled by a light source control circuit that includes: a pixel data output unit; a pixel data correcting unit that corrects a skew between main scanning line of electrostatic latent image and photosensitive element and a local deviation of the electrostatic latent image on the main scanning line, and outputs pixel data; a pattern generating unit that outputs pixel data for forming a predetermined pattern in an electrostatic latent image; a first light source control unit for causing a first light source, that needs correction of the local deviation, to emit light; a second light source control unit for causing a second light source, that does not need correction of the local deviation, to emit light; and a switch that switches between a first transmission status and a second transmission status.

Abstract: A light emitting control device for a light emitting diode print head includes a control unit, a pulse-mask unit, a strobe unit and a data output unit. The pulse-mask unit outputs n clock signals in sequence to a light emitting diode print head. The strobe unit outputs a strobe signal to the light emitting diode print head, so as to switch on the light emitting diode print head. The data output unit outputs a print data signal to the light emitting diode print head. When the pulse-mask unit outputs a k-th clock signal of the n clock signals, the pulse-mask unit delays the k-th clock signal for a predetermined time, and the data output unit pauses outputting the print data signal. After the predetermined time, the pulse-mask unit and the data output unit continue to output the rest of the clock signals and the print data signal.

Abstract: An image forming apparatus includes: a light source; a light-source driving unit; a photosensitive member including an image forming region; a determining unit determining a level of a rotation speed of the photosensitive member; a scanner unit exposing the photosensitive member by deflecting the light beam from the light source by a deflecting unit; a sensor receiving the light beam and outputs a detection signal; and a control unit controlling the image forming apparatus based on the detection signal output from the sensor. When the determining unit determines that the rotation speed is low, the light-source driving unit is configured to drive the light source to emit the light beam when a deflecting direction of the light beam is oriented toward the sensor and not to drive the light source to emit the light beam when the deflecting direction of the light beam is oriented toward the image forming region.

Abstract: The image forming apparatus includes a video controller unit that receives image information to convert the image information into an image signal for image formation, an engine controller unit that controls image formation, a laser driver unit that emits a laser beam, and a plurality of signal lines that connect the video controller unit, the engine controller unit, and the laser driver unit to each other, wherein the laser driver unit detects the laser beam emitted from the illumination element and generates a horizontal synchronization signal which is electrically transmitted via any one of the plurality of signal lines and used as the reference of an image writing timing in response to the detection. Among the signal lines, a signal line for transmitting the image signal or a control signal electrically and a signal line for electrically transmitting the horizontal synchronization signal are used as a common signal line.

Abstract: An optical writing device includes two or more light sources. The two or more light sources can be driven independently, are placed away from each other in a sub-scanning direction of a photoreceptor, and each distance of beams emitted from the light sources to the photoreceptor is different. A phase control unit causes a difference in phase among timing control data of two or more beams emitted from the two or more light sources by a phase change amount, which is determined on the basis of beam position of the each beam on the photoreceptor in a main scanning direction and varies depending on the beam position. The modulating unit modulates the timing control data of the respective phase-controlled beams by a same clock.

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: A light scanning apparatus including: a light source to emit a laser beam; a light source driving unit to turn on and off the light source according to image data and a pixel clock; a rotary polygon mirror to deflect the light beam; a motor to rotationally drive the rotary polygon mirror; and a control unit to control a rotary speed of the motor to generate an acceleration control signal for accelerating the rotary speed and a deceleration control signal for decelerating the rotary speed, wherein for the acceleration control signal, the driving unit corrects the frequency of the pixel clock to be higher than the frequency, which is before the acceleration control, and for the deceleration control signal, the driving unit corrects the frequency of the pixel clock to be lower than the frequency, which is before the deceleration control.

Abstract: An exposure device includes a long board, plural light emitting elements arranged along a longitudinal direction of the board on one face of the board, plural inspection electrodes arranged along the longitudinal direction of the board on the other face of the board, and plural electrical wirings each electrically connects between one of the plural light emitting elements and one of the plural inspection electrodes that is not positioned nearest to the one of the plural light emitting elements.

Abstract: An image forming apparatus includes an optical scanning unit, a measurement unit, a first adjustment unit and a second adjustment unit. The optical scanning unit includes a plurality of light sources to emit laser beams, a single oscillating mirror deflector to deflect the laser beams used for scan processing in a main scanning direction, and a scan-focusing member to focus the deflected laser beams onto a plurality of photoconductors. The measurement unit measures a resonance frequency of the oscillating mirror deflector. The first adjustment unit adjusts a speed of the photoconductors in a sub-scanning direction. The second adjustment unit adjusts a magnification ratio of image data in the sub-scanning direction. The first adjustment unit and the second adjustment unit adjust the image magnification ratio of image data in the sub-scanning direction depending on the resonance frequency as measured by the measurement unit.

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: An image forming apparatus including; an exposure section provided with, a light emitting element, a polygon mirror to receive light beams from the light emitting element, and to expose an image carrier using light beam via the polygon mirror based on image data; an image processing section to adjust image magnification by image processing of the image data; and, a control section configured to select at least either of a first magnification adjustment to change a rotation speed of the polygon mirror and a second magnification adjustment to carry out image processing of the image data by the image processing section, based on comparison results between a paper interval time during recording paper conveyance in image formation and the first magnification adjustment time required to stabilize polygon mirror rotation in the first magnification adjustment, when adjusting image magnification with respect to recording paper.

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: One aspect of this invention relates to an illumination device for an optical printer, the illumination device comprising: a first array of light sources comprising a plurality of light source elements that are each operable to emit light within a red band of the visible electromagnetic spectrum; a second array of light sources comprising a plurality of light source elements that are each operable to emit light within a blue band of the visible electromagnetic spectrum; and a third array of light sources comprising a plurality of light source elements that are each operable to emit light within a green band of the visible electromagnetic spectrum; wherein said first, second and third arrays of light sources are generally linearly arranged along respective substantially parallel notional lines on a substrate; and said plurality of light source elements of each said array are arranged such that respective adjacent light source elements of said plurality are offset from one another with respect to the associated

Abstract: An exposure device for exposing a photoreceptor, includes: data electrodes disposed for each of a plurality of columns parallel to a moving direction of the photoreceptor; selected electrodes disposed for each of a plurality of rows perpendicular to each of the data electrodes; light emitting element arrays including light emitting elements disposed near intersection points between the data electrodes and the selected electrodes in intersections between the data electrodes and the selected electrodes, the light emitting elements being linearly arrayed; a driving signal output circuit for generating a driving signal based on an image signal to supply the driving signal to the light emitting element arrays; and a column selection unit for switching the light emitting element arrays to be selected based on a lighting situation of each of the light emitting elements of each of the light emitting element arrays.

Abstract: According to one embodiment, when performing monochrome image forming, image processing circuits for color image forming, laser control circuits for the color image forming and data processing circuits for the color image forming in an integrated circuit are not operated.

Abstract: A light-emitting device includes: a circuit board including at least two of signal interconnection layers each having plural signal interconnections, at least adjacent two of the signal interconnection layers including signal interconnections provided so that center positions of the respective signal interconnections in a direction intersecting with a longitudinal direction are displaced from each other in portions of the signal interconnections provided in the longitudinal direction; and plural light-emitting chips each having plural light-emitting elements, the light-emitting chips being arrayed in line in the longitudinal direction on a surface of the circuit board.

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 pixel information acquiring unit acquires multilevel pixel information in which one pixel is expressed in multilevel scales. A line pixel information storing unit stores the multilevel pixel information for each main scanning line. A light emission control unit optically exposes a photosensitive element by controlling a binary light source on the basis of the multilevel pixel information. The photosensitive element is exposed to the binary light source with a period corresponding to N-fold in a sub scanning direction resolution of the multilevel pixel information, wherein N is a positive integer, so that the N times exposures corresponds to an exposure for one pixel in an original resolution. The switch on/off statuses of the binary light source are controlled in the N times exposures for each pixel, on the basis of lighting rate information for converting the multilevel scales into a lighting rate in the N times exposures.

Abstract: An optical writer includes a scanning part causing a light beam from a light source to perform scanning on a photosensitive body; an image information obtaining part obtaining image information of an image; a dithering information obtaining part obtaining dithering information of the image; a pixel clock generating part generating a pixel clock signal; and a light emission control part to control the light source based on the image information in accordance with the pixel clock signal. The pixel clock generating part modulates the clock frequency of the pixel clock signal in accordance with phase shift information for correcting a change in the speed of the scanning on main scanning lines on the photosensitive body, and determines the timing of modulating the clock frequency based on the dithering information on a main scanning line basis so that the timing of modulating the clock frequency differs between the main scanning lines.

Abstract: A driver circuit in an optical print head uses driving transistors to drive a row of light-emitting elements. The gate electrodes of the driving transistors are at least partly oriented so that driving current flows in the channels below the gate electrodes in a direction different from the direction of the row the light-emitting elements. This orientation reduces the temperature dependency of the driving current, so that the optical print head can produce the same high image quality at low ambient temperatures as at room temperature.

Abstract: Provided is a line head including: a light emitting device array in which N (N is an integer of 2 or more) light emitting device groups including a plurality of light emitting devices is arranged; an output unit which sequentially outputs driving signals for driving the light emitting devices of the light emitting device groups to the light emitting device groups; and a delay unit which delays input timings when the driving signals output from the output unit are input to the light emitting devices, wherein the delay unit delays the input timings of the 1 to (N?1)th driving signals output from the output unit to the input timings of the Nth driving signals output from the output unit, and allows the light emitting devices of the different light emitting device groups simultaneously to emit light.

Abstract: An exposure device includes a plurality of light-emitting elements, a lighting driver, a first storage, a reader, a shading correction unit and a second storage. The lighting driver drives and lights up the light-emitting elements based on image data. The first storage stores light amount unevenness correction values of the respective light-emitting elements. The reader reads the light amount unevenness correction values stored in the first storage. The shading correction unit executes shading correction for the light amount unevenness correction values read by the reader. The second storage stores correction values obtained by having the shading correction unit to execute the shading correction for the light amount unevenness correction values. The lighting driver controls light power of the respective light-emitting elements based on the correction values stored in the second storage.

Abstract: Laser printers are plagued with an assortment of alignment issues. In color laser printers the issues are exacerbated. Variations in distance from the mirror to the drum can lines in different color planes to vary in size. Variations in angles in the facets of the mirror can cause alignment issues between lines. Even lack of synchronization between the dot clock and start of line indication can cause misalignment between rows. In addition, a cosine distortion occurs due to the non-constant linear velocity of the laser scan of a single line. A very high speed master clock can drive the laser scanning unit. By using a very high speed clock, the control circuitry has the resolution to compensate for many of these distortion types, by appropriately counting clock cycles and indicating such to the laser modulator.

Abstract: An optical writing apparatus includes a light source device that includes a VCSEL having an alignment of at least two channels in a sub scanning direction configured to emit plural light beams in a block. A deflector deflects the plural light beams toward an image bearer that forms an image by changing a line speed of image formation. A control device decreases a number of light beams by turning off a prescribed same number of the channels symmetrically from the both ends of the alignment in accordance with the line speed.

Abstract: Systems, apparatuses, and methods for selecting bits from a defined print image in memory of a handheld imaging translation device are described herein. The bits may be selected by determining a location of a print nozzle, mapping the location to a memory location, and selecting a bit from the memory location. Other embodiments may be described and claimed.

Abstract: A print head, including: a plurality of chips disposed in a linear array; respective pluralities of first and second matrix drivers on each the chip connected to first and second channels, respectively; and for each chip, first groups of light-emitting diodes (LEDs). Each first group of LEDs includes: a second group of LEDs, with a first number of LEDs, connected to a respective first matrix driver; and a third group of LEDs, with the first number of LEDs, connected to a respective second matrix driver. LEDs in each first group of LEDs are disposed in a staggered arrangement; and the respective pluralities of first and second matrix drivers are for activating in sequence the LEDs in the second and third groups of LEDs, respectively.

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: A light-emitting device includes: light-emitting chips each including light-emitting elements and memory elements corresponding to each other, each memory element memorizing a light-emitting element to light up, each light-emitting chip being capable of lighting up the light-emitting elements in parallel; a unit to transmit an enable signal in common to light-emitting chips belonging to each of M groups obtained by dividing the light-emitting chips, the enable signal enabling selection of light-emitting elements to light up; a unit to transmit a write signal in common to light-emitting chips belonging to each of N classes obtained by dividing the light-emitting chips, the write signal setting memory elements corresponding to the light-emitting elements to light up, to a memory state or not, in the light-emitting chips where the selection is enabled; and a unit to transmit light-up signals for lighting up to light-emitting elements corresponding to memory elements in the memory state.

Abstract: There is provided an exposure device including: plural exposure heads having plural light-emitting elements arranged in a first direction, the plurality of exposure heads also being arranged in the first direction; plural temperature detecting units for detecting temperature arranged at both ends in the first direction of each of the plural exposure heads; and a correction unit for correcting quantities of light emitted from the exposure heads based on temperature data detected by the temperature detecting units.

Abstract: An image forming apparatus includes light sources, a light intensity controller, an optical writing unit, a controller, and an image forming unit. The light sources are switchable between activated and deactivated conditions according to supplied image data. The light intensity controller controls light intensity of the light sources. In the optical writing unit, light beams output from the light sources are deflected in a main scanning direction. The controller sets a given number of light sources to activated condition to write a latent image on an image bearing member according to an image forming line speed. The controller instructs the given number of light sources to emit light beams onto an image area on the image bearing member, and instructs all of the light sources to emit light beams at a blank area on the image bearing member to execute a light intensity control for all of the light sources.