Abstract: A write control circuit for controlling driving of a plurality of light sources each including a laser diode for emitting light includes a plurality of write control mechanisms configured to control the plurality of laser diodes to perform writing for image forming with a plurality of colors. Each of the plurality of write control mechanism includes at least one image development part for developing and processing image data and at least one laser diode control part for controlling driving of the laser diodes.

Abstract: The light-emitting device includes: a self-scanning light-emitting element array including: light-emitting elements; memory elements; and switch elements; and a light-up controller supplying a transfer signal setting ON of the switch elements, a memory signal causing, in a case where a switch element corresponding to a light-emitting element forming a group is set at the ON state, a corresponding memory element to be temporarily changed from OFF to ON if the light-emitting element is to light up, and the corresponding memory element to be kept in OFF if the light-emitting element is not to light up, and then causing the memory element having been temporarily changed to the ON state to be temporarily set at ON again, and a light-up signal for each group, the light-up signal causing a light-emitting element to be set at ON after causing a memory element to be set at ON.

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 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: 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: A drive circuit for supplying a drive current to a plurality of driven elements includes a plurality of drive output terminals to be connected to the driven elements. The drive output terminals are arranged with a specific pitch in between in an arrangement direction. The drive circuit further includes a plurality of drive transistors. Each of the drive transistors is arranged in an occupied area with a specific width in the arrangement direction larger than the specific pitch.

Abstract: An image forming apparatus includes an exposing unit and a first processing component. The first processing component is configured to generate a first data and a second data. The first data causes the exposing unit to blink in accordance with image data. The second data sets a blink mode of the exposing unit. The image forming apparatus also includes a second processing component connected to the first processing component through a first signal line. The second processing component is configured to receive the first data and the second data from the first processing component and perform blink control of the exposing unit based on the first data and the second data. The exposing unit is connected to the second processing component through a second signal line. The image forming apparatus thus can remedy a defect in data communication to the exposing units.

Abstract: A light-emitting element array drive device includes: plural light-emitting elements; plural switch elements electrically connected mutually in an array and respectively to the light-emitting elements, and setting the respective light-emitting elements ready to emit light when turned on, and unready to emit light when turned off; a transfer signal supply unit supplying transfer signals for getting the switch elements turned-on by sequentially switching each switch element from being turned-off to turned-on, and to turned-off, where periods during which the respective switch elements are turned on are displaced so that each two periods for two of the switch elements adjacently-connected overlap; and a light-emission signal supply unit supplying a light-emission signal having light-emitting periods for the light-emitting elements, where an end point of each light-emitting period is set based on a start point of the above overlap, while a start point thereof is set before each end point.

Abstract: A recording head is supplied capable of generating a plurality of concentration dots on the same line without providing a complicated circuit. The recording head has a recording device array in which a plurality of recording devices are arranged, and comprises a first input terminal which inputs a first driving signal for deciding a first driving time; a second input terminal which inputs a second driving signal for deciding a second driving time; a selecting section which selects whether or not the driving signal of the first input terminal or the second input terminal is used for each of the recording devices; and a driving circuit which drives the corresponding recording device by the driving signal selected by the selecting section, wherein the plurality of recording devices of the recording device array are driven by selected signals on the basis of print data.

Abstract: An exposure head includes a light emitting segment that emits light; an electrical load that is electrically connected to a circuit in which a current to be supplied to the light emitting segment flows; and a current supply controller that supplies a first current to the light emitting segment to cause the light emitting segment to emit light and supplies a second current to the electrical load during the time when the current supply controller blocks the supply of the first current to the light emitting segment.

Abstract: An image forming apparatus in which a BD signal, which is a main-scanning reference signal, and image data are input to an image signal generating unit. Using a converting unit, main-scanning coordinate information, output from a main scanning coordinate measuring counter, and correction amounts, recorded in a correction amount LUT, are referred to, to convert a proper amount of image data. Here, the converting unit performs calculations in accordance with the main-scanning coordinate information, to obtain the image data of correction amounts that differ in accordance with coordinates. The correction amounts are in correspondence with different amounts of driving current in a main-scanning direction. Therefore, laser light emission, which provides a light quantity in accordance with the image data, is controlled.

Abstract: An image forming apparatus includes: a light source that emits a light beam; a photosensitive member; a driving motor; a rotary polygon mirror, which is rotated by the driving motor, and which periodically deflects the light beam emitted from the light source to sequentially form scanning lines on the photosensitive member; a position detecting unit, which detects a rotational position of the driving motor, and which outputs a detection signal; a sensor, which receives the light beam deflected by the rotary polygon mirror, and which outputs a light receiving signal; a detecting unit, which receives the detection signal and the light receiving signal, and which detects a rotation direction of the driving motor based on a timing pattern of a detection of the rotational position of the driving motor and a reception of the light beam by the sensor.

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 thermosensitive recording printer is provided with semiconductor lasers 1a to 1c, a polygon mirror 7 for condensing laser light emitted from the semiconductor laser 1a to 1c as condensed spots on a recording medium 10 to perform scanning in a main scanning direction, and a control unit 9 for controlling the output of the laser light. If a ratio of a spot diameter D1 of the condensed spots in the main scanning direction and a spot diameter D2 in a sub scanning direction satisfy a relationship of D1/D2?½ at the time of forming an image composed of a plurality of pixels on the recording medium 10 using laser light, high-speed thermosensitive recording and a recording method with an uncomplicated power control are realized without reducing the power density of the condensed spots.

Abstract: A light-source driving device includes a high-frequency clock generating circuit that generates high-frequency clock signals of which phases are different from each other; an image-data generating circuit that generates a plurality of pieces of image data corresponding to light emitting units in accordance with image information; a write control circuit that generates a plurality of pieces of modulation data corresponding to the light emitting units based on the image data and adjusts output timing of the modulation data individually in units of time corresponding to a phase difference of the high-frequency clock signals; and a light-source driving circuit that drives the light emitting units based on a plurality of pieces of PWM data output from the write control circuit.

Abstract: An image-data transfer controller divides one line of image data for each of the light-emitting-element array units, transfers the divided image data to respective light-emitting-element array units, to drive each of the light-emitting elements in the light-emitting-element array units for an exposure in a main-scanning direction. The image-data transfer controller divides the one line of image data for each of the light-emitting-element array units and transfers the divided image data during one-line interval in the main-scanning direction, performs a plurality of data transfers in the one-line interval for driving each of the light-emitting elements by controlling a lighting time, and includes a plurality of lines of storing units.

Abstract: A scanning laser having a wavelength compatible with a coating binder so as to cure it as the laser scans and irradiates the coating on a moving web. A system and method for curing flakes by providing a scanning laser which scans across a moving coated substrate in a magnetic field allows images to be formed as magnetically aligned flakes are cured into a fixed position. The images have regions of cured aligned flakes. The scanning laser cures the magnetically aligned flakes within it region it irradiates. Alternatively an array of lasers can be used wherein individual lasers can be switched on and off to fix irradiated coating as a moving web is moved at a high speed.

Abstract: The light-emitting device includes: a setting unit switching a potential difference between anode and cathode electrodes alternately between first and second potential differences so that light-emitting thyristors are caused to have one of the first and second potential differences in common; a specifying unit sequentially specifying, as a target for controlling, one light-emitting thyristor; a supply unit alternately supplying transition voltage for causing specified light-emitting thyristor to transition from the off state to the on state and maintaining voltage for keeping the thyristor being in the off state to a gate electrode of the thyristor, in a light-emission control period during which the specifying unit specifies the target and the setting unit sets the second potential difference; and an adjusting unit that adjusts a light-emitting period of the one light-emitting thyristor by supplying the maintaining voltage and stopping supplying the voltage at a variable timing, in the light-emission control

Abstract: A driving apparatus having driving circuits formed to correspond to driven circuits arranged on a circuit board. Each driving circuit includes a driving control unit for driving the corresponding driven circuit, a reference voltage generation unit for generating a reference voltage according to a temperature of the corresponding driven circuit, a control voltage generation unit for generating, based on the reference voltage supplied from the reference voltage generation unit, a control voltage for driving the corresponding driven circuit, the control voltage generation unit supplying the generated control voltage to the driving control unit, a switch device formed between the control voltage generation unit and the reference voltage generation unit, and a switch control unit for driving the switch device based on an inputted control signal. The control voltage generation unit is connected to the reference voltage generation unit of another of the driving circuits via the switch device.

Abstract: An optical print head including, a first element row in which a plurality of light emitting elements aligns in a predetermined direction; a second element row in which a plurality of light emitting elements aligns in a predetermined direction, which aligns with the first element row in a direction orthogonal to the predetermined direction, and deviates in the predetermined direction with respect to the first element row; a data sorting circuit which outputs image data corresponding to an exposure region formed on a photoconductor due to light emitting of the first element row, and image data corresponding to an exposure region formed on the photoconductor due to light emitting of the second element row, at timings which are different from each other; and a driver which drives the light emitting elements in the first element row and the second element row, by receiving an output from the data sorting circuit.

Abstract: An image data is pre-processed in parallel by a pre-processing unit (A) and a pre-processing unit (B) arranged in parallel. The image data is transferred in synchronization with an image processing signal obtained by ORing a BD signal and an interpolation signal. Laser scanning for plural beams of a multi-laser beam is performed in synchronization with the BD signal. Color matching processing or zeronization processing for the multi-laser beam is performed in synchronization with the image processing signal.

Abstract: An image forming apparatus which performs exposure for “n” lines in one scan by scanning “n” light rays from “n” light sources in a main scanning direction of an image carrier, where “n” is an integer greater than 1, including: a laser driving section; and a control section which, corresponding to density unevenness generated in an adjoining section of a nth exposure in a Nth scan and a first exposure in a N+1th scan, determines a correction value of exposure amount to resolve the density unevenness for the nth exposure amount in the Nth scan and the first exposure amount in the N+1th scan, along with that, determines a correction value of each exposure amount for the “n” lines, based on the correction values of the first and nth exposure amount.

Abstract: For suppressing density unevenness which is caused by changes in a main scanning line interval of a laser beam on the image bearing member due to a polygonal face tangle, laser luminance is controlled so as to maintain the density unevenness with a spatial frequency sensitive to human visibility substantially constant.

Abstract: A drive device for outputting a drive signal for driving a plurality of light emitting elements time-divisionally, the drive device includes a plurality of input terminals receiving input of a drive control signal for the light emitting elements, and a plurality of output terminals connected to the light emitting elements, for outputting the drive signal based on the drive control signal input into the input terminals, in which the input terminals and the output terminals are arranged substantially in a line.

Abstract: An image formation apparatus for executing image formation by exposing an image carrier with irradiation light emitted from a laser source on the basis of an input signal to drive the laser source includes a correction amount calculation unit configured to calculate, on the basis of a generated correction pattern, a correction amount to control the ON or OFF timing to drive the laser source, and a signal generation unit configured to generate, on the basis of image data and the correction amount calculated by the correction amount calculation unit, a corrected signal obtained by correcting the input signal to drive the laser source so as to form the image data by controlling the ON or OFF timing.

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: According to one embodiment, a laser controller generates a signal which corresponds to an output signal of a laser beam detection sensor before detecting an abnormality, in which the abnormality is detected, in a pseudo manner, on the basis of an output signal of a laser beam detection sensor in which the abnormality is not detected. In addition, the laser controller controls a laser unit which corresponds to the laser beam detection sensor in which the abnormality is detected, according to the generated signal.

Abstract: An image forming apparatus includes a laser exposure device including plural laser oscillators, at least two pattern detection sensors to detect a pattern of forced light emission lines formed on a transfer belt by forced light emission of the plural laser oscillators at a time of initialization of the laser exposure device, and a shift amount calculation part to calculate a position shift amount between the forced light emission lines from output signals of the pattern detection sensors.

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: A light-emitting element head includes: plural light-emitting element array chips that are divided into plural groups and that each are provided with light-emitting elements arranged in an array; a signal generation unit that generates a light-emission control signal for controlling blinking of the light-emitting elements, and an identification signal for identifying which of the light-emitting element array chips in each of the groups the light-emission control signal is for; signal lines through which the light-emission control signal and the identification signal are transmitted; and identification signal discrimination units that are connected to the signal lines and that are provided in the respective light-emitting element array chips, each of the identification signal discrimination units discriminating the identification signal, and transmitting the light-emission control signal to the light-emitting elements.

Abstract: An optical head expresses gray scales of pixels, which belong to a block constituted by n pixels and m pixels in a first and second direction, respectively. The optical head includes light emitting devices that extend in the first direction and emit light; driving transistors that are provided corresponding to the light emitting devices; a potential line that applies potential to the driving transistors; and driving circuits that are provided corresponding to the driving transistors and that supply a driving control signal to gates of the driving transistors. The driving circuits each include a line having an intersection at which the line intersects the potential line; and a logic circuit that generates the driving control signal based on image data to instruct the light emitting devices. The logic circuits invert logic levels of the lines at the intersections every n number of intersections extending in the first direction.

Abstract: An optical scanner includes a light source modulated based on image data, an optical deflection and scanning part deflecting a light beam emitted from the light source, and a scanning and imaging optical system condensing the deflected light beam toward a scanning surface so as to form a light spot optically scanning the scanning surface. The effective scanning region of the scanning surface is divided into a plurality of regions according to a scanning line curving characteristic. Suitable image data for optically scanning the divided regions are selected from image data of a plurality of image lines every time the light spot optically scans the effective scanning region, so that the image data of each of the image lines is written with scanning line curving being corrected.

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 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: An image forming apparatus for simultaneously conducting multiple lines of exposure by scanning multiple laser beams from multiple light sources onto an image carrier in a main scanning direction, including: multiple light sources which are driven to emit laser beams based on image data; and a control section capable of controlling an image formation in two types of image forming modes of a first image forming mode where an image is formed at a first image forming speed by using all the multiple light sources, and a second image forming mode where the image is formed without using at least one of the multiple light sources at a second image forming speed slower than the first image forming speed, wherein the control section controls a light source which is not used in the second image forming mode to emit a laser beam onto outside of an image area.

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 optical scanning device includes at least one scanning unit having a deflector for scanningly deflecting a light beam from a light source, and an imaging optical system for imaging the light beam scanningly deflected by the deflector upon a plurality of photosensitive drums, wherein, at each of a plurality of light paths extending from the deflector to the plurality of photosensitive drums, at least one reflection member for turning the light path into a sub-scan direction is provided, wherein the plurality of light paths are different in the number of the reflection members, wherein a polarization direction of a light beam incident on each reflection of the plurality of light paths is S-polarized at an optical axis of the imaging optical system, wherein the reflection surfaces of all the reflection members of the plurality of light paths have the same film structure, and wherein the difference among the plurality of light paths of a total turn angle defined by the reflection surface or surfaces of the ref

Abstract: A drive circuit includes a drive element for supplying a drive current to a driven element; a control voltage generation circuit for outputting a control voltage to the drive element to generate the drive current through inputting a reference voltage; and a switch section for shutting down the reference voltage when the driven element is not driven so that the control voltage decreases to a level not to generate the drive current.

Abstract: A light emitting apparatus includes optical thyristors, a driver circuit that supplies a drive current to the thyristors so that the thyristors emit light, and a control circuit that controls the thyristors. Each thyristor includes an anode, a cathode connected to the ground, and a gate. The thyristor emits light when the drive current flows therethrough. The control circuit controls the gate, causing a control current to flow from the anode to the gate to turn on the thyristors. The control circuit applies a control voltage to the gate, the control voltage being higher than a voltage appearing across the gate and the cathode when the thyristor remains turned on.

Abstract: An exposure device includes a plurality of light emitting elements, a load, a first supplying unit and a second supplying unit. The first supplying unit supplies a driving current to one of (i) light emitting elements used to form an image among the plurality of light emitting elements and (ii) the load, in accordance with a modulation signal. The first supplying unit supplies a bias current to the other. The second supplying unit supplies the bias current to light emitting elements not used to form the image among the plurality of light emitting elements, regardless of the modulation signal.

Abstract: An optical head includes a plurality of unit regions repeatedly arrayed in one direction. Each region is constituted by a light-emitting element which is driven by a current to emit light, a control transistor which is connected in parallel with the light-emitting element, and which receives gray-scale data that specifies a high gray-scale level for the light-emitting element so as to be turned off and which receives gray-scale data that specifies a low gray-scale level for the light-emitting element so as to be turned on, and a driving transistor which is connected in series with the light-emitting element to generate a current. In each of the plurality of unit regions, a thermal resistance between the light-emitting element formed in the unit region and the control transistor formed in the unit region is smaller than a thermal resistance between the light-emitting element and a control transistor formed in a unit region adjacent to the unit region.

Abstract: An optical scanning apparatus capable of being applied to an image forming apparatus includes a light source which emits a light beam; a modulator which pulse-width modulates drive current supplied to the light source; and a current adding unit which adds a supplemental current to the pulse-width modulated drive current at the rising edge of a pulse thereof.

Abstract: A continuous-sheet printing tandem electrophotography system for printing a continuous sheet includes first and second electrophotography units. A first size of the continuous sheet is measured before an image printed by the first electrophotography unit with a first parameter value is fused on the continuous sheet. A second size of the continuous sheet is measured after the image printed by the first electrophotography unit is fused on the continuous sheet. The second electrophotography unit then prints the continuous sheet with a second parameter value that is determined by a size difference between the first and the second sizes. The first and the second sizes include a page length and a page width of the continuous sheet. The parameter values include a print speed, a polygon mirror rotating speed, a video clock frequency, and a laser power.

Abstract: Attribute information accessory to a pixel can be used to determine whether to execute an interpolation process of less than one pixel at a scan line changing point in color misregistration compensation for a printout from an image forming apparatus having a characteristic shifted in the laser scanning direction for each color. When the attribute information is an attribute representing execution of the interpolation process of less than one pixel, it is enlarged in the sub-scanning direction. Attribute information of each color component can be generated from attribute information accessory to a pixel by using the attribute information accessory to the pixel, and each color component value which forms the pixel.

Abstract: In a line head, a plurality of element arrays arranged in a first direction. Each array includes a plurality of light emission elements arrayed in a second direction which is perpendicularly to the first direction. The light emission elements emit light for forming an electrostatic latent image on a photosensitive surface of an image carrier. A switcher activates the light emission elements in at least one of the element arrays while deactivating the others. A developer develops the latent image as a visible image with toner.

Abstract: The invention relates to an optical printer head 12 provided with one or a plurality of light emitting element array units 3. The light emitting element array unit 3 is provided with a circuit board 30, a base member 33 supporting the circuit board 30, and a plurality of light emitting elements mounted onto the base member 33 and arranged in a row in main scanning directions M1 and M2. The base member 33 has a lower hygroscopic rate than the circuit board 30. The plurality of light emitting element array units 3 are arranged along the main scanning directions M1 and M2, for example, so that end portions 34 in adjacent light emitting element array units 3 are overlapped with each other in vertical-scanning directions S1 and S2.

Abstract: An exposure device includes plural light emitting elements that light in turn for exposure, plural driving elements that drive each of the light emitting elements and a time changing member that changes one time period of a switching signal to switch light emitting elements driven by the driving elements among the plurality of light emitting elements in turn from a reference time, depending on an image forming speed, wherein the time changing member changes the one time period from the reference time for some of the light emitting elements during one main scan, and maintains the one time period as the reference time for the remaining light emitting elements.

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: The light-emitting element head includes: a first signal supply unit supplying a first signal for sequentially specifying a plurality of light-emitting elements one by one as a control target for control in common to light-emitting element chips; a second signal supply unit supplying second signals for giving an instruction to emit or not to emit light to one of the elements specified as the control target to a set of light-emitting element chips so that each of the signals is supplied in common to plural light-emitting element chips belonging to each of N groups into which the set of chips are divided; and an enable signal supply unit that supplies enable signals for allowing the set of chips to receive the second signals which are different from one another so that the enable signals are supplied respectively to the chips belonging to each of the N groups.

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 voltage circuit connected to the switch circuit for adjusting the drive current at a constant level.