Abstract: An optical scanning device is provided with a light source that emits a light beam, a driver that controls output power and modulation of the light beam emitted by the light source, a controller that transmits, to the driver, power control data and modulation data respectively used for controlling the output power and modulation of the light beam. The optical scanning device is further provided with a single data bus that connects the driver and the controller. The power control data and the modulation data being transmitted through the single data bus at different timing.

Abstract: In order to realize edge smoothing in an image printing apparatus using a plurality of laser beams, commonality of a data processing circuit to the plurality of laser beams is attained by obtaining image data for the plurality of scanning lines in synchronism with a common scanning position of one of the plurality of laser beams and storing the image data into a common memory and generating laser modulating data for each of the laser beams; temporarily the laser modulating data for the other laser beams into FIFOS; using the laser modulating data in synchronism with the respective scanning positions of the plurality of laser beams to generate laser modulating signals for the respective laser beams in a PWM.

Abstract: The present invention provides an exposure device capable of operating at a high speed and obtaining an excellent printing result. The exposure device according to the present invention includes optical write heads using shift registers of two systems, and a circuit that supplies image data for one line divided into the first half and the second half to the respective shift registers. The circuit is consist of a write control section, a memory, a read control section and a transfer control section), and receives data of twice the number of bits of data inputted to the shift register.

Abstract: An electrophotography apparatus has a charging unit, and an exposing unit, and a developing unit. The charging unit charges the surface of a rotating image bearing body having an axis of rotation. The exposing unit emits light to illuminate the surface of the image bearing body to form an electrostatic latent image on the surface. The developing unit applies charged toner to the electrostatic latent image to develop the electrostatic latent image into a visible image. The electrophotography apparatus includes, for example two electrodes and power supplies for applying voltages to the electrodes. The electrodes are disposed between the light-emitting surface of the exposing unit and extend parallel to the axis of rotation of the image bearing body. The electrodes are aligned on opposite sides of the light emitted from the exposing unit.

Abstract: In an electrophotographic image formation, a driving current for laser emission is pulse-width-modulated in correspondence with externally input image data. The pulse width modulation of the driving current is started after a predetermined time period has passed from a time point of beam detection by a light detector located at a position leading a photosensitive drum in a main scanning direction. The driving current is adjusted in correspondence with the light amount detected. Current adjustment data is supplied to a current modulation circuit in the same manner as image data. Detection is made of the laser beam, which is pulse-width-modulated by the current modulation circuit on the basis of the supplied adjustment data, and is emitted from the laser light source, by a laser monitor device under control of a monitor controller.

Abstract: A method for controlling a radiation intensity of a laser beam emitted by a laser having a threshold current level above which the laser emits the laser beam, the method including the steps of: supplying an electrical driving current for driving the laser, the electrical driving current increasing up to about the threshold current level; subsequently immediately further increasing the electrical driving current to a value above the threshold current level for causing the laser to emit the laser beam; and an image exposure device implementing this method.

Abstract: A laser imaging system having a diode laser for producing a laser beam; a beamsplitter for splitting the laser beam into a laser writing portion and a feedback portion; a photodetector for detecting the feedback portion; a photodetector amplifier for amplifying the output of the photodetector; a sample and hold coupled to the photodetector amplifier; an integrator adder; an integrator for integrating the outputs of the photodetector amplifier and the sample and hold processed by the integrator adder; and a laser input circuit including a laser amplifier, a linear power signal provider, a threshold power signal provider, and a laser input adder for adding the laser power signal, the linear power signal, and the output of the integrator.

Abstract: A printer controller 41 sets compensation values, representing the positional deviations of LED array chips 31, in a delay circuit section 68 via shift register 61 and a latch circuit 63. The shift register 69 sequentially acquires bit map data from the printer controller 41, and supplies the acquired bit map data to an AND gate 66 through the latch circuit 62. Upon receiving a strobe signal from the printer controller 41, the delay circuit section 68 supplies the received strobe signal to the AND gate 66 after a delay time corresponding to a preset compensation value has lapsed. The AND gate 66 generates drive signals each being the logical product of the input bit map data and the strobe signal, and supplies them to the LED array chips 31 through a buffer 67. The LED array chips 31 make LEDs emit light at the timings corresponding to the positional deviations so that images are formed without a positional deviation.

Abstract: The present invention relates to a pulse generation apparatus for generating a pulse signal having a pulse width controlled, and a pulse signal having a pulse width controlled with high precision is generated by a circuit suitable for conversion into LSI.

Abstract: The magnification of an image in the main scanning direction thereof is altered by making the frequency of the image clock variable. At this time, if the pre-SOS lighting signal and the APC signal are output synchronously with the frequency of the image clock, then an SOS signal may not be output from the SOS sensor and control of the amount of light of a light beam may not be accurately executed. Therefore, the timings of the outputs of the pre-SOS lighting signal and the APC signal are controlled so as to normally be output at a uniform timing (i.e. the periods from the input of the SOS signal until the outputs of each signal are made uniform).

Abstract: In a color image recording apparatus provided with plural print heads and a conveyor, each print head includes a plurality of recording elements aligned along at least a single line in a primary scanning direction and the plural print heads are arranged in parallel to each other in the primary scanning direction so that plural component images of the color image are formed parallel respectively by the plural print heads. A reference component image forming device controls the plural pieces of print heads so as to form and superimpose plural reference component images based on the reference component image data and timing setting values. A timing correcting unit analyzes positional deviations in the secondary scanning direction among the plural superimposed reference component images and corrects the timing setting values on the basis of the positional deviations in the secondary scanning direction.

Abstract: A first embodiment of an adjustment circuit for a laser diode output power compensator includes a feedback circuit for adjusting the laser diode output power compensator so that the output power of the laser diode is substantially constant. The feedback circuit includes a photodiode for measuring the output power of a VCSEL diode. The signal from the photodiode is coupled to a first amplifier. The difference between the signal from the photodiode and a first reference value is amplified and coupled through electronic switches to selectively charge one of multiple capacitors. The multiple capacitors are each coupled to one of a drive current source, a compensation current source, and a voltage controlled resistor, each of which are voltage controlled. A second amplifier is used for amplifying the difference between the signal from the photodiode and a second reference value to charge a capacitor coupled to a voltage controlled bias current source.

Abstract: A printer includes LED heads and head controllers. Each head controller transfers items of data to a corresponding head over a set of common buses. The LED head has a receiver activated by a corresponding head selecting signal. In one configuration, the common buses may include a selector bus over a data bus. Image data and a group of signals are alternately transferred over the data bus, the group of signals including a latch signal for latching the image data into a corresponding head and a strobe signal for driving a corresponding head in accordance with the image data. The selector signal allows the receiver to direct the image data and the group of signals into separate data paths. In another configuration, the control signals may further include an image clock and a control clock.

Abstract: In a method of driving a plurality of optical output media aligned in one direction in an optical writing apparatus that drives activation and deactivation of the optical output media based on image data to thereby perform optical writing onto an object onto which writing is to be performed, it is determined whether the number of optical output media that are writing-driven based on the image data in order to perform optical writing onto the object is smaller than the total number of optical output media, and when the number of writing-driven optical output media is smaller than the total number of optical output media, non-writing driving of optical output media other than the writing-driven optical output media is performed. The non-writing driving is a driving in which optical writing is not performed onto the object.

Abstract: An electrophotographic printer has a print head that illuminates a photoconductor to form an electrostatic latent image. The print head has light-emitting elements. Each corresponding to a pixel of the image and emitting light when driven. Drive circuits are provided for driving the light-emitting elements. Each drive circuit drives a corresponding one of the light-emitting elements in accordance with a value of the pixel. A controller controls the drive circuits to start driving corresponding light-emitting elements in a predetermined order.

Abstract: Compact and inexpensive color printers can be manufactured. An exposure head using linearly-aligned organic EL elements each composed of subpixels each emitting light of R, G, and B is used as a light source. Input color image data are dealt with as color data corresponding to each of the color components R, G, and B. For each color data, each of the organic EL elements is caused to emit light in accordance with line data for one line corresponding to all organic EL elements composing the exposure head, and a photosensitive material is exposed to the light. After completion of the exposure, vertical scan means moves the photosensitive material by a predetermined amount in the vertical scan direction and the photosensitive material is exposed in accordance with image data corresponding to a subsequent line, as has been described above. By repeating this procedure, exposure corresponding to all image data is carried out.

Abstract: An image forming apparatus includes: a plurality of light-emitting elements, each light-emitting element receiving a driving current from a power supply and converting the current into a beam; a plurality of driving elements, each driving element being interposed between the power supply and each light-emitting element and controlling the driving current based on an image signal; and a photoconductor on which the beams from the plurality of light-emitting elements form an image by scanning, wherein each light-emitting element is positioned so immediately adjacent to each driving element that a power leakage factor floating therebetween is reduced, whereby an intensity of the beam is substantially equivalent to the image signal in waveform.

Abstract: An optical shutter drive period detector detects a drive period of each optical shutter element. Based on the detected drive period, an optical shutter drive voltage control device sets an optical shutter driving voltage which is applied to an optical shutter driver. Furthermore, an optical shutter open period controller sets an optical shutter open period corresponding to the set optical shutter driving voltage and to a tone level of a pixel to be exposed and the optical shutter open period is input to the optical shutter driver as data for changing an optical shutter open period. Based on the optical shutter driving voltage and the optical shutter open period changing data, the optical shutter driver drives each optical shutter element of an optical shutter array, an electrostatic latent image is formed on a surface of a photosensitive drum, and the electrostatic latent image is developed by a developer, transferred by a transfer/separation charger onto a recording sheet and discharged.

Abstract: Regardless of a relative installation position error between a light source and a photosensitive material, or of a deviation from a properly preset value of rotation speed of a photosensitive material, images are obtained with minimum loss of image quality and excellent reproducibility. The number m of light-emitting elements to make up a unit and the distance between adjacent pixels formed on the photosensitive surface are adjusted such that the width of the pixel groups is ⅓ mm or less, which is a period that the periodic image noise is not recognized as stripes.

Abstract: The exposure device of an image forming apparatus includes a light-emitting device array having light-emitting devices; a switching device array including switching devices connected to the light-emitting devices, the switching device array being divided into a plurality of groups; a first line group for connecting commonly to first terminals of switching devices of each of the groups; a second line group for connecting commonly to second terminals of switching devices of each of the groups; and a circuit for performing simultaneous light emission of the light-emitting device array to expose the photosensitive member.

Abstract: An electrocoagulation printing apparatus has a printing head with an array of electrodes in contact with an electrically conductive electrocoagulation printing ink, and a driver circuit for impressing electric signals to individual electrodes of the array. The driver circuit includes a current limiter for limiting the magnitude of electric current passing through individual electrodes and the electrocoagulation printing ink to a predetermined value. The current limiter corrects a density of adjacent ink film pixels of a printed line to compensate for a cross-influence of impedance between adjacent ink film pixels.

Abstract: An optical write head operable in high speeds is provided with better printing results. The optical write head is arranged by an LED array constructed of a plurality of LEDs arrayed in a line form, one shift register used to store thereinto pixel data for a front half portion of this LED array, and the other shift register used to store thereinto pixel data for a rear half portion of this LED array. The optical write head is further arranged by registers for latching parallel pixel data outputted from these shift registers, and a driving circuit for simultaneously driving the LEDs employed in the LED array in response to patterns of the pixel data outputted from the registers when a control signal is inputted.

Abstract: A writing devices for an image forming apparatus of the present invention determines whether or not an image at and around an interval between nearby light emitter chips of a light emitter array is of halftone. If the image is of halftone, the writing device corrects image data corresponding to the above interval in order to increase the quantity of light. This successfully reduces or fully obviates the local omission of an image ascribable to intervals between nearby light emitter chips and insures a smooth output image.

Abstract: To achieve a reduction in the size of the print head and a reduction in the cost, LED array chips 1 achieved by matrix-connecting M×N LED elements 2 with M pad electrodes to be scanned 4 and N pad electrodes to be driven 3 and LED array drive ICs 10 are mounted at a mounting substrate 41. The pad electrodes to be driven 3 are connected with drive pad electrodes 16 and the pad electrodes to be scanned 4 are connected with scan pad electrodes 17 through wires 42a and 42b respectively. The pad electrodes to be driven 3 and the pad electrodes to be scanned 4 are provided in a single row along one side or edge of the lengthwise side of the chip.

Abstract: In an image recording apparatus provided with an optical unit having a plurality of laser diodes; a driving circuit is provided to drive the plurality of laser diodes in accordance with image output signals applied with a predetermined first bias; and a beam intensity measuring element is provided to measure a beam intensity of each of beams emitted from the plurality of laser diodes. When the beam intensity measuring element measures the beam intensity of each of beams emitted from the plurality of laser diodes, the driving circuit switches the first bias applied to at least one of the plurality of laser diodes to a second bias smaller than the first bias.

Abstract: Gray scale printing data with compensation for dispersion is stored in a first shift register, the data is sliced into respective bits and is fetched by means of a second shift register and AND-gates. Standard resistances are scanned by means of a third shift register and switches, in synchronization with the data retrieval, for changing standard current, and light emitting current to light emitting bodies is changed according to the standard current.

Abstract: A method for controlling the intensity of an imaging laser of an electrophotographic device in order to produce both positive and negative output. This is accomplished by using a software controlled digital circuit to increase or decrease the power supplied to the laser based on the user's desire to print positive or negative output. When the user desires to print positive output, the laser is set to full power. When the user selects negative mode printing, the power to the laser is digitally reduced by a factor unique to the electrophotographic characteristics of the printing device.

Abstract: An integrating xerographic light emitter array includes circuitry for using organic light emitting diodes (OLEDs) operated at modest light levels to expose a photoreceptor drum or belt. This is accomplished by staging an array of the emitters in the slow scan direction and clocking the data through pixel driving shift registers synchronously with the movement of a photoreceptor past the array in the slow scan direction. Increased emitter lifetime and the ability to operate at lower light levels are achieved in proportion to the number of stages. The method for operating the xerographic light emitter array includes transmitting data signals to the first row pixels, shifting the data signals down the columns synchronously with photoreceptor movement and supplying current to drive the OLEDs. Multicolor devices for xerocolography and tandem or multipass color architectures are straightforward extensions of this design.

Abstract: A device for correcting the non-linearity of a scanner comprising: a reset pulse generator for generating a reset pulse with a predetermined pulse width in synchronization with a scanning start signal generated corresponding to an input photosensitive belt sensing signal; an address generator for outputting an address by being reset by the reset pulse; a look-up table, that is initiated by the scanning start signal, for receiving an address from the address generator and for outputting information corresponding to the address in the form of digital data; and a converter for outputting a synchronizing signal with a frequency corresponding to the digital data from the LUT. Another aspect of this invention is a method for correcting the non-linearity of a scanner.

Abstract: A printer includes a photosensitive drum which is exposed by a line head which includes a fluorescent head having a large number of light points which are aligned in a direction of a width of the photosensitive drum, and the respective light points of the fluorescent head are driven by a line driver in accordance with drive data from a shift register which holds the drive data for all the light points. One print line is formed by a set of four sublines. In a case where the thinning of a line width is corrected in a main scanning direction, the print line is formed by sublines more than five, whereby the line width is fatted.

Abstract: A light emitting apparatus including a photosensitive member and an exposure device including a light emitting device array made up of a plurality of light emitting devices arranged in a direction of main scan across a moving direction of the photosensitive member and a switching device array made up of a plurality of switching devices arranged and connected to the light emitting devices in one-to-one relation. The switching device array is divided into a plurality of groups, a first group of leads connected in common to first terminals of the switching devices for each of the plural groups of switching devices, a second group of leads connected to second terminals of each of the switching devices, and a third group of leads, each of the third group of leads connected to third terminals of each switching device in a respective group of switching devices.

Abstract: It is an object to provide an image recording apparatus for recording an image of high resolution at a high speed. An electrostatic latent image is recorded onto a photosensitive material by using a recording head which has a plurality of switching elements which are arranged in an array shape and sequentially turn on the adjacent switching elements and light emission element arrays of a plurality of columns each of which is constructed by arranging light emission elements, in an array shape, which are connected to the switching elements and which are arranged in almost parallel, and in which each of the switching elements turns on the corresponding light emission element, so that the plurality of light emission elements are scanned. Developing means develops the electrostatic latent image and transfer means transfers the developed latent image onto a recording paper.

Abstract: A method is used for correcting amounts of light of light emitting elements. A first correction range is defined which has a median of maximum and minimum values of the amounts of light of the light emitting elements, and includes a predetermined number of first subdivided ranges. If the minimum amount of light is not within the first correction range, a second correction reference is produced which is smaller than the first correction reference by a predetermined fraction of the difference between the maximum and minimum values. Then, a second correction range is defined which includes the minimum amount of light, has the second correction reference in its middle, and includes a predetermined number of second subdivided ranges.

Abstract: A multi-beam scanning system has a beam control using an Electrostatic Voltage Sensor or an Image Density Sensor on the Organic Photoconductor. The laser beams can be attuned according to the voltage or density results. This results in a more reliable system as compared to the use of one or more photodetectors.

Abstract: A printer or copier has an optical character generator for reproducing raster image data in grey-scale displays. Integrated light sources in the form of LEDs arranged in arrays are aligned to form a print line. A control IC is provided for each LED array. Groups of the control ICs are formed in which information is shifted for the switch on time of all LEDs of a group starting with the first control IC to the next IC. The ICs are connected together by bonding. A ramp circuit is provided to prevent current surges when the LEDs are switched on. A flat unit that extends along the character generator is used to transmit information and power to the control ICs. Busbars ensure that power is provided to the LEDs.

Abstract: In a non-impact recording apparatus that includes a plurality of recording elements, there is provided a source of first data signals representing for each of plural pixels density, size or percentage of coverage for recording. A first look-up table memory is responsive to the first data signals for adjusting the density, size or percentage coverage of each of the pixels with a gamma adjustment related to density development by the apparatus and generates multibit gamma adjusted second data signals. A second look-up table memory generates a third signal related to a characteristic of the recording elements such as for nonuniformity correction. A process look-up table memory is responsive to the gamma adjusted second data signals and the third signals for generating fourth multibit signals relating to exposure on-times for recording pixels by the recording elements. The use of the three look-up table memories results in substantial saving in memory requirements.

Abstract: In a laser scan based recording apparatus, laser light from a measuring laser diode is directed to one reflecting surface of a polygonal mirror. The reflected light is detected with a measuring photodiode. The reflectance of laser light is calculated from the detection output of the measuring photodiode and a reference voltage is generated. When the reflecting surface has rotated to the position where the laser light from laser light source scans a photoreceptor drum, the emission output of the laser light source is controlled by a laser output control circuit on the basis of the generated reference voltage. Despite variation in reflectance among the multiple reflecting surfaces of the polygonal mirror, the photoreceptor is scanned with a constant optical intensity of laser light. Since automatic power control is performed at all times, overdriving of the laser diode is effectively prevented to protect it against breakdown, producing consistent and highly reliable laser power control.

Abstract: An integrating xerographic light emitter array includes circuitry for operating an active matrix array of organic light emitting diodes (OLEDs). The light emitter array stages rows of emitters in the slow scan direction and moves the object image and synchronization with the photoreceptor. Grey scale resolution, increased emitter lifetime and the ability to operate at lower light levels are achieved in proportion to the number of stages. The entire printbar can be rewritten during each line time of the photoreceptor, which allows the exposure on any pixel on the photoreceptor to be varied in a number of grey levels from zero to the number of stages. Bringing a grey level signal to the photoreceptor allows improved continuous tone image quality and line placement. Additional grey resolution is obtained by analog driving of individual pixels. This technique is applicable to a variety of emitters or light valves, but is particularly suited to inexpensive OLEDs.

Abstract: A non-impact printer apparatus and method wherein enabling waveforms for enabling a plurality of recording elements for recording pixels are characterized by pulse durations that can vary by one exposure clock pulse period with some recording elements being enabled after others so that some of the benefits of center pulsewidth modulation (CPWM) are provided without the disadvantages of CPWM of pulsewidths being at least two exposure clock periods apart.

Abstract: A raster output scanner is disclosed which utilizes a replaceable laser diode and a replaceable microchip which contains characteristics information of the laser diode in use by the raster output scanner. Once, the laser diode is replaced, the microchip has to be also replaced by a microchip which contains the characteristics information of the new laser diode.

Abstract: A light scanning device deflects a plurality of light beams by a deflecting means performs divided scanning on a single scanning line on a photoconductor with the plurality of deflected light beams. When the scanning line is scanned, a detecting means detects a light beam passing through a predetermined position in front of a position where the light beam first strikes an image forming range on the photoconductor. An oscillating means oscillates a specified number of clocks in a time interval from when the light beam is detected by the detecting means until it is detected thereby again. An adjusting means makes adjustments so as to irradiate a plurality of light beams based on clocks oscillated by the oscillating means. In a time interval after the light beam is detected by the detecting means until it is detected thereby again, a plurality of light beams are irradiated based on the specified number of clocks.

Abstract: A printer including a light emitting body for emitting light along a main scanning direction. A photosensitive surface of a photosensitive body is sensitized by the light emitted from the light emitting body. The photosensitive surface is moved relative to the light emitting body at a predetermined distance along a sub scanning direction perpendicular to the main scanning direction. While the photosensitive surface is moved at the predetermined distance along the sub scanning direction, the light emitting body emits the lights at a predetermined period. The predetermined period is determined to be a time required for moving the photosensitive surface at a dimension of the light emitting body along the sub scanning direction.

Abstract: An image sensor array includes a plurality of photosensor chips, which are butted end-to-end to form a single linear array of photosensors. Each individual chip in the array is provided with an independently-addressable output enable line and video output line. This configuration allows individual chips to be addressed to output image data at specific times and in a specific manner suitable for any kind of downstream circuitry.

Abstract: A system and method of calibrating pulsewidth modulation of a laser. The output power of the laser is determined and a signal indicative of the output power is provided to a printer system control computer. The control computer calibrates the pulsewidth modulated signal responsive to the signal indicative of the output power. In a preferred embodiment, the control computer includes a lookup table or a mathematical model. The control computer compensates for timing variations in the pulsewidth modulated signal induced by system components and environmental operating conditions.

Abstract: A light-emitting device includes a number of light-emitting element groups each including a plurality of light-emitting elements, a first drive device for driving the plurality of light-emitting elements in succession, and a number of resistance sections, each separately connected to each of the light-emitting element groups. The resistance section is connected in common to the plurality of light-emitting elements. The light-emitting device further includes a second drive device for driving the light-emitting element groups.

Abstract: An image recording apparatus which performs time division and driving of 128 recording devices arrayed within an LED chip includes shift registers for sequentially serially outputting 128 bits of continuous pixel data to 56 signal lines, corresponding to each LED, from one line of serially input pixel data row, selectors which perform time division of the 56 pieces of pixel data into 8 times of 7 pieces apiece and then outputs the data, and registers which hold the pixel data output from the selectors for each corresponding LED chip. The image recording apparatus may be used as a recording head for a printer using solid recording devices is simplified, and costs are reduced.

Abstract: A driving apparatus has driving circuits that supply driving energy to driven elements which form dots. The driving circuits are controlled by driving data indicating which driven elements are to be driven, and compensation data adjusting the amount of driving energy. The compensation data are stored in compensation memory circuits coupled to the driving circuits. A single data transfer means transfers the driving data to the driving circuits and the compensation data to the compensation memory circuits. If the driven elements are located on two or more different semiconductor chips, some of the compensation data preferably compensate for chip-to-chip differences, while other compensation data compensate for dot-to-dot differences within the same chip.

Abstract: Pulse width modulation of signals, such as provided to a driver in a laser printer, is phase locked to a beam detect signal. In addition, it must permit continuously variable, arbitrarily small pulses at extremely high speeds. This invention describes a novel method and system using multiple streams of variable phase clocked outputs. The variable phase clocked outputs are combined with a clock generator to achieve these goals at low cost. As a result, the pulse width modulated signals provide continuously variable selectable pulse widths at extremely high speed.

Abstract: An image signal processor of a printer is provided.

Abstract: An array of laser diodes, or laser diode bars, is formed by positioning adjacent diodes or bars in an offset or staircase arrangement where the emitting facets of adjacent diodes, or bars, are in different planes. The offset arrangement permits the light from adjacent facets to be separated a distance q much shorter than permitted by prior art stacking arrangements because thermal and mechanical constraints characteristic of prior art stacks, are relaxed considerably in the offset arrangement. Power densities of 2000 watts/cm.sup.2 (cw) are achieved with spacings of 0.6 mm between adjacent laser bars, a ten fold increase in power density over in-plane (prior art) positioning of like components.