Abstract: An LED printer which forms a printed image by driving an LED head comprises a smoothing circuit in the LED head driving circuit the smoothing circuit forms interpolation lines by matching the original lines of the input data signal having a vertical resolution of 200 dpi with a given pattern and produce a print data signal of 400 dpi so as to improve the resolution of the printed image. The LED head driving circuit comprises a circuit for detecting the printing condition related to the image to be printed and producing a printing condition signal comprised of a line counter for detecting whether the line to be printed is the original line or the interpolation line, a transition counter point for counting the transition points of the input data signal between black and white dots, a dot counter for detecting the print density of the input data signal and a resolution detecting portion for detecting the resolution of the input data signal.

Abstract: An LED printer includes a printing control unit and an LED head. When a video signal received at the control unit has a higher resolution than the LED head, the control unit carries out the logical AND between successive bit data of the video signal to convert the video signal to a first signal. Corresponding to a line timing signal, this first signal is transferred as a head data signal to the LED head and is then printed on a basic raster scanning line. Further, the control unit also carries out the exclusive-OR between the successive bit data of the video signal so that the video signal is converted to a second signal and outputted to a line buffer. Corresponding to an additional line timing signal, the second signal is transferred as another head data signal to the LED head and is printed on an additional raster scanning line. The LED head drive energy for performing printing along the basic raster scanning line is set independently.

Abstract: A recording head includes a light emitting element array comprised of a plurality of light emitting elements and a plurality of switch elements for scanning the plurality of light emitting elements, and a drive device for driving the light emitting element array. The drive device has a variable resistor in a route for supplying a driving current to the plurality of switch elements. The control voltage of the variable resistor is varied to thereby adjust the driving current for the plurality of switch elements.

Abstract: A pixel array driver for applying gray level voltages to a group of pixels without the use of a ramp voltage generator employs an integrated circuit arrangement which multiplexes a plurality of discrete gray level voltages in staircase fashion onto a high-voltage bus, identifies each of the discrete voltages appearing on the high-voltage bus with a code word applied to a code word bus, and matches for each pixel the word on the code word bus to a previously stored data word that designates the gray level intensity voltage desired at the pixel. When the code word and the data word match, the pixel is disconnected from the high-voltage bus. Each pixel is provided with a sample and hold circuit to maintain the value of voltage reached after being disconnected from the high-voltage bus.

Abstract: An image recording apparatus has an array light source having a plurality of light-emitting elements arrayed in a predetermined density; a photosensitive member exposed to light beams emitted from the plural light-emitting elements so that images are recorded by fixing a traveling path of the light beams from the plural light-emitting elements to the photosensitive member and by moving the photosensitive member relative to the array light source; a beam-converging unit which intercrosses a bundle of the light beams emitted from the light-emitting elements onto a beam-conversion point; and an focusing unit disposed between the beam-converging unit and the photosensitive member, which images the light beams emitted from the plural of light-emitting elements and intercrossed by the beam-converging unit onto the photosensitive member.

Abstract: In a image processing system for an electrophotographic printer, a density selective circuit selects density data of a pixel to be corrected in response to the black-and-white patterns of surrounding pixels in a line matrix, and a density correction operation circuit outputs a picture signal with corrected density data corrected by the selected density and other density correction coefficients, thereby the toner adhesion amount, i.e., the printing density is made uniform and a clear printed picture without density unevenness can be obtained irrespective of the content of the picture signal.

Abstract: An LED head includes a circuit board and a plurality of LED arrays aligned on the circuit board in a longitudinal direction of the circuit board. Each of the plurality of LED arrays includes a row of a plurality of first LEDs aligned in the longitudinal direction between a second LED and a third LED. The second and third LEDs are at the end of the row. The first LEDs have a width W1 in the longitudinal direction and the second LED and the third LED have a width W2 in the longitudinal direction. The width W2 is smaller than a width W1. The first, second, and third LEDs have the same dimension D in a direction perpendicular to the longitudinal direction. The first, second, and, third LEDs are aligned at predetermined intervals P1 and the plurality of LED arrays are aligned such that the first, second, and third LEDs are aligned in the predetermined intervals P1.

Abstract: An image forming apparatus, which judges whether image forming is permitted when a pre-registered identification number is received, includes an input mode setting unit for setting either a first mode or a second mode, where the first mode deals with a numerical string received by an input receiving unit as a first identification number, and the second mode deals with the numerical string received by the input receiving unit as a second identification number. The image forming apparatus also performs display control to have a display unit not display the received numerical string in the case where the first mode is set and to have a display unit display the received numerical string in the case where the second mode is set.

Abstract: A fault-tolerant self-replacing xerographic light emitter array includes circuitry for operating an array of organic light emitting diodes (OLEDs). The light emitter array provides imaging from a single row of imagers which operate at high brightness and high current. The emitter area is extended by having multiple rows of emitters. When one or more of the pixels of a currently-selected row burns out or decays to a level insufficient for imaging, a new row is activated and imaging continues. This is possible because the emitter rows are closely spaced and share an optical lens wide enough to collect light with adequate throughput for all rows. This redundancy permits imaging to continue without adjusting or replacing any mechanical parts of the emitter array. In addition, because of the fault-tolerant design, a single bad row or pixel does not render the device unusable. This technique is applicable to a variety of emitters or light valves, but is particularly suited to inexpensive OLEDs.

Abstract: An electrostatographic reproduction method and apparatus includes an electrostatic recording member moving in a process direction. A plurality of recording elements on a writer imagewise expose the recording member to form electrostatic latent images on the recording member. The writer includes driver circuitry for actuating selected recording elements. The exposed recording member is then moved through a development station to develop the latent images. The developed images are transferred to a record member. An operator selectable adjustment controller is manually adjusted for generating adjustments in operation of the recording elements to compensate for a misalignment of a process station in the apparatus.

Abstract: A photographic recording apparatus capable of being small-sized and simplified in structure and reducing color aberration of an optical system. A refractive index distribution type lens array has a central axis arranged perpendicularly to a light emission direction of a fluorescent luminous tube. Light emitted from the fluorescent luminous tube passes through red (R), green (G) and blue (B) color filters, is incident on the lens array, is reflected on a first mirror and then is guided to a color film, resulting in forming an image on the color film. The fluorescent luminous tube is driven depending on data on R, G and B colors and the whole apparatus is moved with respect to the color film. The color filters are changed over and scan of the color film is carried out three times, so that an image of R, G and B colors may be formed on the color film.

Abstract: An optical scanning apparatus includes light beam emitter that emits a plurality of light beams, such as laser beams having different wavelengths, respectively; light beam deflector that deflects the plurality of light beams emitted by the light beam emitter that scans an object; guider that guides the plurality of deflected light beams so that the deflected light beams fall at about the same position on the object; light receiver that receives the reflected light beams reflected from the object of reading; and image information generator that generates image information representing the object based on the reflected light beams.

Abstract: A driver chip for use in an LED or other multi-element recording printhead includes a plurality of current driver channels. Data for determining recording durations for each of the current driver channels is provided on a data bus. A token bit is shifted through a shift register in association with image data to be latched by registers corresponding to a specific driver channel. The driver chip is operational in different recording resolution modes so that it may be connected to recording arrays of different resolutions. When operational in other than its highest or higher resolution, a by-pass signal is generated causing the token bit to by-pass certain stages of the shift register.

Abstract: A non-impact printer apparatus and method employs a printhead including a plurality of recording elements and drivers for driving respective recording elements in response to data relative to respective corrected exposure times for recording respective pixels. A first data storage device stores data relative to associating sets of respective recording elements with respective bins. The first data storage device is responsive to first input signals identifying respective recording elements and outputs second signals relative to respective bin assignment numbers for the respective recording elements. A second data storage device is responsive to the second signals for outputting data relative to corrected exposure times for recording respective pixels by respective recording elements. The bin assignment determination for recording elements are established by propagating exposure error calculated from an adjacent respective recording element.

Abstract: A print head for non-impact printer is, for example, an LED head which comprises a plurality of light-emitting elements, LED drivers for selectively causing a drive current to flow into the light-emitting elements on the basis of the print data, a non-volatile memory for storing the modification data related to the value of the drive current. The modification data are determined in advance at the manufacturing process on the basis of the measured result when the light-emitting elements were driven by the LED driver so that all the light-emitting elements emit substantially same amount of light at the printing operation.

Abstract: Disclosed is a multi-beam laser scanning device which scans a surface to be scanned with a plurality of laser beams in accordance with an image data. Each image data includes driving pulses which periodically occur in each image data, and are representative of intensity of laser beams. Phase of the image signals are shifter with each other so that the driving pulses do not overlap within a period of the driving pulses.

Abstract: An optical character generator for an electrographic printer has a plurality of monolithic circuits (11) which are arranged on a carrier (10) and have LEDs (12) which are integrated in the circuits and can be driven individually. The monolithic circuits (11) include a monolithically integrated photodiode drive combination, in the case of which both the associated LEDs (12) and the drive circuit (13), possibly including a BUS circuit (14) for the LEDs (12), are integrated in a monolithic circuit (11). The monolithic circuits are constructed using thin-film technology from III-V semiconductor material, preferably GaAs.

Abstract: A light signal generating device wherein a line of light shutter elements made of PLZT are turned on and off individually in accordance with a driving signal corresponding to image data, and each turned-on light shutter element generates a light signal. The light shutter elements are impressed with a specified voltage by order of a composite signal made by combining a modulation signal modulated in accordance with the image data and a micro duration pulse signal.

Abstract: An apparatus for compensating LED printbars, and printers which use LED printbars, for aging. Changes in the slopes of the forward voltage drop verses forward current characteristics (the I-V characteristics) of the LEDs of the LED printbar are determined. The drive currents of the LEDs are then changed as a function of the changes in the slopes so as to compensate for changes in the LED light outputs.

Abstract: A non-impact printhead having a plurality of driver IC chips and and a plurality of recording elements such as LEDs. Each driver IC chip includes a plurality of current-carrying channels that are operative for carrying current to respective recording elements on the printhead and a control for controlling operation of the driver.

Abstract: A method for connecting selected bonding pads of a universal current driver IC supporting a maximum resolution, e.g., 600 DPI, with the appropriate bonding pads of the same or a lower resolution LED chip array. The output pads of the current driver IC and the pads of the LED elements of each LED chip array or segment are matched so that wire bonding takes place between the physically closest pads. Consequently, the universal current driver IC may be employed with LED chips or segments of a certain standardized length that contain 96 LED elements for 300 DPI, 128 LED elements for 400 DPI, and 192 LED elements for 600 DPI or the like. The selection algorithm, in picking the physically closest IC current driver pad to be connected to an LED element pad leaves certain stages of the IC driver unconnected.

Abstract: Apparatus for estimating LED printhead junction temperature as a function of an input data stream, and for automatically compensating the printhead drive signal to maintain proper printer calibration to provide junction-level compensation for efficiency loss of an LED as the LED warms due to thermal energy generation from an electrical drive current is effected by a plurality of selectable LED temperature-specific look up tables constructed for a plurality of different LED temperatures. The selected look up table produces an output for driving the LED when the selected look up table is accessed by the input data. A model of the thermal characteristics of the LED, its heat sink, and the structure attaching the LED to the heat sink is adapted to produce an estimate of the temperature of the LED as a function of the image data. An address decoder selects one of the plurality of look up tables to process the input data stream in accordance with the estimate produced by the model.

Abstract: A printhead includes a plurality of recording elements such as LEDs each having a light output characteristic related to a driving parameter such as current. A plurality of driver circuits establishes the driving parameter for driving the recording elements. The driver circuits are mounted on a circuit board. A flex circuit having a conductive pattern electrically connects the driver circuits to the recording elements. The driver circuits include resistors for use in regulating the driving parameter. In lieu of mounting the resistors on the circuit board, the resistors are instead advantageously mounted on the flex circuit for controlling current to the respective recording elements. This allows the resistors and recording elements to be replaced without the need to also replace or modify the circuit board in the event that more efficient recording elements are to be used.

Abstract: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The remaining bit data of the received video signal, which are not converted into the first signal are converted into a second signal representing another data sequence corresponding to the resolution of an LED head. The LED head includes a resolution conversion circuit which converts the video data into the first signal and the second signal. The signals are stored in a shift register having a plurality of line buffers. The first signal is printed on a basic raster line and the second signal is printed on an additional raster line. An LED head drive energy with which basic raster lines are printed and another LED head drive energy with which additional raster lines are printed are set independently of each other.

Abstract: When exposing thermally imageable materials using a multi-channel exposure head, an overlap of at least one channel is used to avoid a visible border at the point where one group of channels, written at the same time, meets a second group of channels. The overlapped area is written twice with identical data.

Abstract: A non-impact printer apparatus includes a printhead having a plurality of recording elements. The printhead further includes a non-volatile memory that stores prebinned data representing recording characteristics relative to the recording elements. The prebinned data includes (a) data associating respective recording elements with respective bins; and (b) data relative to a characteristic of each bin. A controller means is located off of the printhead for generating tables for correcting for non-uniformity of the recording elements. The controller uses the prebinned data for generating the tables.

Abstract: An intensity controlling circuit device can correct variation in intensity of light beams, due to tolerance occurred in each of a plurality of LED-array chips, emitted by LEDs provided in each of the LED-array chips. The intensity controlling circuit device is connected to at least one LED-array chip comprising a plurality of LEDs and slave transistors corresponding to each of the LEDs. The intensity controlling circuit device comprises an intensity controlling circuit connected to the respective LED-array chip. The intensity controlling circuit comprises a first transistor provided between a power source and a constant current generating unit so as to supply a current to the LED-array chip, and an intensity adjusting unit having a second transistor connected to the first transistor in parallel and a controlling unit for controlling the on/off state of the second transistor.

Abstract: An apparatus has a plurality of semiconductor cells as current switchings for driving a laser diode which exposes to light a photosensitive member so as to effect image recording. The semiconductor cells have each different characteristics, or same characteristics respectively. In response to the light amount signal corresponding to light quantity of the laser diode, a selector selects one or more of the semiconductor cells so as to supply a suitable driving current turned on or off later with an image signal. As a result, no fluctuations in the pulse duty ratio and the rise time are present in the entire driving current active range, thus improving the quality of a recorded image. The effect of selection by the selector is held for a certain recording time, whereby malfunction due to noises or the like can be avoided, and stable actions of the laser diode are ensured.

Abstract: In an apparatus for forming an image on a recording medium by using a group of recording elements including a plurality of recording elements aligned in an array form of at least a single line, a controller controls each recording element so as to be driven plural times for each pixel in accordance with image data and controls the plurality of recording elements in such a way that while one group of the plurality of recording elements is in an operable condition as working elements, neighboring recording elements located next to the working elements are controlled to be in an inoperable condition as non working elements.

Abstract: A non-impact recording apparatus and method is described for recording pixels on a recording medium by recording sub-pixel recording portions of the pixel represented by a multibit recording data signal having a most significant data bit and a least significant data bit in a series of consecutive subline recording intervals. The apparatus includes one or more recording elements that are drivable by driver currents to generate recordable output signals such as light or ink droplets or heat. A driver provides driver currents to each recording element during plural subline recording intervals to record the pixel. One driver current is provided during one subline interval for one duration that is different than a second driver current that is provided during a second subline interval for a second duration.

Abstract: In an LED printhead or the like, a plurality of LED arrays are arranged in a row. Opposite the LED arrays are driver IC chips providing current in respective current driving channels to respective LEDS. Current to an LED for recording of a pixel will be provided for say a duration related to a multibit image data signal. A data bus is provided for carrying the data signals. The data signals are latched in respective data registers associated with each current driving channel. A token bit shift register is provided for identifying a respective data register for latching of the multibit image data signal presently on the data bus. A direction of shifting of the token bit is determined through automatic self-sensing of the token bit itself as the token bit is moved from a boundary scan register that forms a part of a boundary scan test architecture.

Abstract: An optical information recording and/or reproducing apparatus includes a first semiconductor laser for generating a light beam for recording or erasing information on an optical information recording medium. Also provided is a second semiconductor laser for generating a light beam for reproducing recording information from the optical information recording medium, and a first direct current supplying circuit for supplying a first direct current to the first semiconductor laser. A second direct current supplying circuit supplies a second direct current to the second semiconductor laser, and a high-frequency current supplying circuit supplies high-frequency currents to the first semiconductor laser and the second semiconductor laser. The high-frequency current supplying circuit supplies a smaller high-frequency current to the first semiconductor laser than to the second semiconductor laser.

Abstract: A light source apparatus for a scanner secures a uniform illuminance. The light source apparatus includes a plurality of light emitting diodes arranged at regular intervals. The light emitting diodes disposed at the periphery are provided with a higher voltage and the light emitting diodes disposed at near the center are provided with a lower voltage, so as to compensate for a loss of the light beam at the outer side. Further, the light source apparatus includes a constant-current source for providing the light emitting diodes with a constant current.

Abstract: A light scanning controller includes a plurality of light scanning parts for forming a latent image on a photoconductor by irradiating it with a scanning laser beam, and a clock controller for generating a timing signal by using a single clock signal obtained from a master clock oscillator to transmit the timing signal to each of the light scanning parts which controls the timing of the scanning laser beam on the basis of the timing signal received from the clock controller.

Abstract: An electrophotographic printer includes a photoreceptor on a drum or belt, a laser beam that is reciprocally scanned thereacross, a beam detect signal circuit for generating a beam detect signal and an asynchronous clock oscillator for generating clock pulses. The printer also includes circuitry for generating a plurality of clock signals that are phase synchronized with the beam detect signal. The circuitry includes a tapped delay line for receiving the asynchronous clock pulses, each tap outputting a delayed clock pulse train. A register/selector circuit is coupled to the taps and is responsive to a transition of the beam detect signal for determining a tap which outputs a 0.degree. phase clock transition that is closely proximate to the beam detect signal. Phase delay logic provides signals indicative of which taps of the delay line circuit manifest clock pulse trains that are closest in time to leading and lagging edges of a 0.degree. phase clock pulse, respectively.

Abstract: The present invention is directed to a laser printer including a printer controller, a printhead including a plurality of lasers formed in an array for receiving modulating image data from the printer controller, a variable magnifying means such as a zoom lens, and a drum on which a receiver member is mounted on which an image is to be printed. The printer controller is arranged to selectively use any one of a set of predetermined microdot matrixing values and a separate sub-microdot matrix associated therewith, and distribute image data to the plurality of lasers based on such microdot and sub-microdot matrixing values. The variable magnification means (e.g., a zoom lens) applies optical magnification or demagnification to light beams from the array of lasers to provide selective variable microdot matrixing values between the predetermined microdot matrixing values of the set.

Abstract: Bit data of a received video signal is partially converted into a first signal representing a data sequence corresponding to the resolution of an LED head. The first signal is transmitted to the LED head in the form of a real printing data signal that is to be printed on a basic raster line in synchronism with a line timing signal. The remaining bit data of the received video signal, which are not converted into the first signal, are converted into a second signal representing another data sequence, and then stored in a line buffer. The second signal stored in the line buffer is transmitted to the LED head in the form of a real printing data signal that is to be printed on an additional raster line in synchronism with an additional line timing signal. The LED head drive energy with which the basic raster lines are printed and another LED head drive energy with which the additional raster lines are printed are set independently of each other. The LED head may be provided with such a resolution function.

Abstract: A non-impact printer apparatus includes a printhead having a plurality of recording elements. Nonuniformities in emission characteristics of the recording elements are corrected using look-up tables (LUT) assemblages that include a first LUT wherein the recording elements are binned in accordance with bin values associated with their emission characteristics and a second LUT wherein bin values, output from the first LUT are used to address various tables providing exposure correction. The first and second LUTs are advantageously dual port RAM devices that allow operation during printing while simultaneously allowing loading of data into the tables for use for subsequent printing. Thus, process conditions may be continually monitored and correction data updated without delaying of current printing which may occur using correction data already stored in the LUT assemblages.

Abstract: A method and apparatus for producing within an imaging area of a charged surface and without significant banding, an array of pixel spots forming image scan lines including a start-of-image scan line. The method and apparatus include a ROS for generating an even number of light beams. The ROS includes a rotating polygon assembly having a plural number of facets `F` for each deflecting the even number of light beams onto the imaging area of the charged surface forming scanning beams for simultaneously each producing an image scan line. The method and apparatus also include a controller for controlling the even number of light beams so that a scanning beam spacing "d" is maintained where "d" is equal to `F`-1, and so that at start-of-producing the pixel spots forming the image scan lines, the beams are offset relative to the start-of-image scan line and only one-half the even number of light beams is deflected onto the imaging area of the charged surface to each form an image scan line.

Abstract: A driver IC includes a plurality of electrode pads on a belt-shaped power supply electrode. The electrode pads are arrayed with a pitch dividing a row of driver circuits into groups of equal number. A power source voltage VDD is supplied through the plurality of the electrode pads. Further, the power supply electrode is disposed between the digital circuits and the driver circuits. A print head includes the driver IC with a plurality of light emitting elements connected thereto. A printer includes the print head in combination with photo sensitive drum, a lens array, a charger, a developer and a transcriber.

Abstract: A multiple-source array for use in thermal printing uses source interleaving to avoid overlapping of the dye-transfer tracks upon the donor material in a single pass. The array includes independently addressable printing element data channels and a data distributor allowing interleaving to be accomplished in the printhead. The printhead also includes pixel replication circuitry that allows pixel replication in both the fast and slow scan directions.

Abstract: A copier/printer system includes an image scanner for scanning a document and providing, after a compression step, digital image scanning signals, P.sub.1, that may be communicated to a computer system for display and editing or alternatively communicated to a grey level printer having a magnetic tape memory. The computer system may be used to display the scanned image for editing by an operator and is coupled to the printer so that the edited image signals, P.sub.2, which may be the scanned signals and a common page description language to modify its usage, may be printed by the printer. The edited image signals, P.sub.2, may be sent to the printer over a suitable network. The printer includes image processing electronics for transforming the edited data, P.sub.2, into device independent data signals, P.sub.3. Such signals may be received by printers of the same type; i.e., those employing similar process and halftone algorithms. The signals, P.sub.

Abstract: A laser printer produces a raster image of plural scan lines of image pixels, each raster scan line separated from an adjacent raster scan line by a pitch distance p. The printer includes a movable photoreceptor and n laser sources, where n.ltoreq.2. The laser sources produce n optical beams, separated by a distance of (n+1)p in a direction of movement of the photoreceptor. A scanner scans the n optical beams in parallel paths across the photoreceptor as they are modulated in accordance with pixel data provided from an image buffer. Control circuitry modulates the n optical beams, respectively, with pixel values from one set of n raster scan lines. The n raster scan lines of the set are separated from each other by a distance of (n+1)p. At the completion of each scan, the photoreceptor is moved by a distance (n.times.p). The n optical beams are again modulated with pixel values from another set of n raster scan lines that are respectively, (n+1)p distant from the n raster scan lines of the first set.

Abstract: An imaging system and method employ a linear perceived optical density interface that produces a substantially linear relationship between digital image values generated by an input imaging device and perceived optical densities of corresponding pixels within a visible representation of the image on film. The interface produces a linear change in perceived optical density in response to a linear change in the digital image values, enabling a system user to achieve predictable changes in appearance characteristics by simply adjusting the digital image values. The user can adjust the appearance characteristics in a flexible manner, without being constrained to a set of fixed transfer functions. The user can also perform desired formatting of the image at the input imaging device. The interface provides a single transfer function that is commonly applicable different input imaging devices, such that development of modality-specific transfer functions is unnecessary.

Abstract: In an LED head operated on a time sharing basis, a multiplexer switches resistances for determining LED currents on LED arrays and assigns appropriate resistance to each array. The multiplexer is operated by block select signals of a block select circuit for time sharing operation, where the number of resistances corresponds to the number of blocks. The multiplexer capacity may also be less than the number of blocks, where the number of resistances less than the number of blocks and the same resistances correspond to more than one block. Output dispersions between arrays are adjusted by appropriate assignment of the resistances. sharing operation. Capacity of the multiplexer correspond to the number of blocks required for time. Gray scale printing is achieved by switching the current determining resistances in accordance with shading degree of image with the multiplexer.

Abstract: Uniformity light output of an LED printbar is achieved by a technique which senses the operational on time of each LED. When the on time difference between the LED with the longest on time and the LED with the shortest on time exceeds a predetermined value, the outputs of at least some LEDs comprising the printbar are compensated for to normalize their light output. This normalization is achieved via a drive circuit which drives each LED based upon correction data, and by determining an update of the correction data based upon the difference between the on time of individual LEDs. The correction data is determined when the difference between the on time of the LED with the longest on time and the on time of the LED with the shortest on time exceeds a predetermined maximum difference.

Abstract: A CPU calculates an optimum inclination angle, an optimum movingspeed (V.sub.X) and an optimum displacement time of delay timing on the basis of input signals commanding resolution, a rotation cycle (T) and the number of beams, supplied from an operating part, and outputs a control signal (V.sub.CONT4) providing the inclination angle to a motor (9). As the result, an LED holder (30) rotates with respect to a central axis (37) at the inclination angle and stops. A zoom lens (24) is adjusted by a control signal (V.sub.CONT3) providing a magnification which is responsive to the resolution. A motor (7) is driven by a control signal (V.sub.CONT2), to drive an exposure head (20) at the moving speed (V.sub.X). A cylinder (36) rotates by a control signal (V.sub.CONT1) in a subscanning direction (Y) at the rotation cycle (T). As the result, an image forming region (34) is inclined with respect to the central axis (37) at the inclination angle.

Abstract: A method and apparatus for calibrating a gray level recording printhead having a plurality of light-emitting recording elements is described. In the calibrating method a light intensity of each recording element is measured. The light intensities measured are quantized into M first cells. For each cell an exposure time t (i, j) is determined wherein i is a number representing number of cells and varies from i=1, . . . M and j is a number greater than one representing a number of gray levels. The set of exposure times {t (i, j)} is sorted to remove duplicate times and define a subset of exposure times {t (k)}. A non-uniformity constant value u is associated with each exposure time t (k). Boundaries for plural second cells are defined wherein exposure times, t (k), within a cell are spaced within substantially about the value u from a time b (n) that is calculated from a cell boundary and also falls within the boundaries of each cell.

Abstract: A method and apparatus for grey level printing includes a plurality of recording elements which are enabled for variable periods of time during a cycle of recording grey level pixels. For each recording element a comparator compares the count in a time-changing exposure counter with a multibit grey level data signal. The exposure counter is decremented/incremented by exposure clock pulses from a programmable exposure clock. The exposure clock includes a master clock and an address counter that provides an incremented address signal in response to each set of N pulses from the master clock. The address signal identifies a location in memory of a set of signals used to generate exposure clock pulses. The set of signals is output in parallel to a serial shift register and shifted out serially to form the exposure clock pulses for decrementing/incrementing the exposure counter.

Abstract: A circuit for driving an LED print head so as to be capable of printing a variety of gray levels, comprises a print controller for generating synchronizing signals and latch clock pulses to be applied to the LED print head, a video clock signal generator means for generating a predetermined number of video clock pulses in response to the sub-synchronizing signals, a video data generating means operated by the sub-synchronizing signals for generating a number of sub-data representing the contrast of one line data in response to the video clock pulses, a contrast mode decoding means for counting the latch clock pulses in one period of the sub-synchronizing signals to generate first, second, third and fourth enable signals, a contrast strobe pulse generating means for generating first, second and third strobe pulses of different periods in response to the first enable signal, and a drive circuit for logically combining the second, third and fourth signals and the first, second and third strobe pulses so as to dr