Abstract: In a laser drawing apparatus, a pattern is drawn on a workpiece by scanning the workpiece with at least one laser beam. The laser beam is modulated on the basis of raster-graphic data, in accordance with a series of clock pulses. A calculator calulates clock-pulse-phase-shift location data, indicative of where a phase of the clock pulses should be shifted, with a unit of less than 2.PI.. The calculation is made on the basis of pixel-dot-pitch discrepancy data measured along a scanning line defined by the scanning laser beam. A clock-pulse-outputting controller controls outputting the clock pulses so that the phase of the clock pulses is shifted, with the unit of less than 2.PI.. The shift occurs whenever the laser beam reaches each of the clock-pulse-phase-shift locations, represented by the clock-pulse-phase shift location data, during scanning of the workpiece with the laser beam. Consequently, a pixel-dot-pitch discrepance in the scanning line can be corrected with a unit of less than a one-pixel-dot size.

Abstract: An image processor includes an input device for inputting image signals, and a correcting device for correcting the image signals. A generating device generates a pulse-width modulation signal responsive to an image signal corrected by the correcting device, and a light emitting device emits light on the basis of the pulse-width modulation signal. A detecting device detects the pulse width of light emitted from the light emitting device, and a setting device sets correction conditions of the correcting device on the basis of the pulse width detected by the detecting device when a predetermined signal is supplied to the generating device.

Abstract: A high resolution continuous tone medical image printer is capable of printing a high resolution image on a plurality of different sized media. In a normal resolution mode, a medical image of m.times.n pixels is printed on a first sized media with a variable pixel clock operating at a first pixel clock rate, and in a second resolution mode where the medical image of m.times.n pixels is printed on a second sized media larger than the first sized media in either or both the line scan direction and the page scan direction, the pixel clock is operated at a pixel clock rate less than the first pixel clock rate such that m pixels are printed per line with the pixel size being larger in the line scan direction and such that lines of pixels are added so that more than n lines of pixels are printed in the page scan direction and such that the beam of light size, the scanner speed and the page scan speed are held constant no matter what sized media is being printed.

Abstract: A non-impact recording method and apparatus comprises recording grey level pixels using a recording element in accordance with a selectable combination of recording element on-time and intensity wherein at least some pixels are recorded using the recording element so that a pixel of one density is recorded using a different recording element on-time and a different intensity than used for recording a pixel recorded at a second density, the selectable combination being predetermined in accordance with a multi-bit signal representing a grey level of the pixel to be recorded. The recording element also records certain other pixels represented by multi-bit signals that define the same grey level using different combinations of on-time and duration to form pixels of different densities over an image area which pixels tend to average out to the density defined by the multi-bit signal for the certain other pixels.

Abstract: A method and apparatus for forming machine readable code on an optical information storage disk is provided. The code is formed by periodically pulsing a laser along a path and directing the laser pulse to a preselected point. The laser pulse is adjusted to a preselected spot length and width. A prerecorded optical disk is placed in the path of said laser pulse at said preselected point. The disk is then selectively moved relative to the laser upon each pulse of the laser so that a machine readable mark is made at a different location in the program area of optical information storage disk upon each laser pulse to form a preselected machine readable code.

Abstract: A method for printing a label on an optical disc using a rainbow graphic cutting system includes storing in a memory a location signal and color information data of the label to be printed on the surface of the optical disc. Corresponding location and data signals from among the location signals and the color information data are selectively output to a laser beam recorder LBR. A label corresponding to the signals output to the LBR is then printed on a surface of the optical disc.

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: 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: A method of producing an image on a printing medium comprises producing a pulse train of modelocked laser pulses, providing a source of image input data in the form of a series of gate pulse of varible length and modulating the pulse train with reference to the gate pulses to produce a gated pulse train for producing the image on the printing medium. An apparatus for carrying out the method is also provided.

Abstract: A color printer is equipped with a digital micromirror device having at least one micromirror array constituted of a number of micromirrors. Each micromirror changes its tilt angle in accordance with a value of mirror drive data of one bit. As the mirror drive data takes a value "1", the micromirror reflects spot light toward color paper, whereas as the mirror drive data takes a value "0", it reflects spot light toward a light absorption plate. During red exposure, red light from a red LED unit is incident upon the digital micromirror device which is then driven by red mirror drive data to expose a red image on the color paper. Next, during radiation of a green LED unit, the digital micromirror device is driven by green mirror drive data to expose a green image on the color paper. Lastly, a blue image is exposed on the color paper by using a blue LED unit. A full-color image is therefore printed on the color paper through three-color line- or frame-sequential exposure.

Abstract: An image forming apparatus for reproducing an image corresponding to a digitized image signal includes; an imaging member; a halftone image forming device for reproducing a latent image composed of a plurality of pixels on the imaging member, and for developing the latent image so that coloring particles are adhered in each pixel being put together as an island, the halftone image including a relatively low density halftone image; and a transfixing device for simultaneously transferring the halftone image and fixing the halftone image onto a recording sheet. The image forming apparatus may further includes an intermediate transfer medium. The island-like toner image reproduces the halftone image clearly.

Abstract: An image forming apparatus includes a photosensitive member; an exposing device for emitting a beam of light in accordance with image data for forming an electric image on the photosensitive member; a plurality of developing devices for developing the electric image formed on the photosensitive member; a controller for controlling, for each picture element, duration of the beam of light emitted from the exposing device in response to an image signal; wherein the controller varies, for each picture element, a maximum value of the duration of the beam of light emitted from the exposing device, depending on which developing device is used.

Abstract: Forming dots on a photosensitive material by irradiating the photosensitive material with a laser beam having a pulse width S (sec) and energy density E (w/cm.sup.2), wherein the pulse width S and the energy density E are within the region bounded by the following formulas:log E=-0.46 log S+3.68log E=-0.46 log S+2.

Abstract: The present invention provides an image forming apparatus comprising a photosensitive member, scan means including light emitting elements for emitting laser beam to scan the photosensitive member, and control means for controlling the illumination of the light emitting elements. Wherein, when a shifting speed of the laser beam on the photosensitive member is v, a length of one side of a pixel is L and a maximum light emitting time of the light emitting element for each pixel is t, the control means controls the light emitting elements to satisfy a relation of t<L/v.

Abstract: A laser thermal system that uses a dye donor produces a desired relationship of exposure to density by modifying the input current waveform supplied to the exposure source. The modification is a combination of amplitude modulation and pulse width modulation in an imagewise fashion. The efficiency and the speed of image formation is increased by bringing the dye donor temperature near the threshold of dye transfer using a segment of the total current waveform for a very short duration.

Abstract: A scanning laser beam heats selected regions of a dye donor ribbon to transfer dye to a receiver sheet to form an image therein. The beam scan rate and delay time between the start of successive pulses is set so that adjacent heated pixel regions overlap and so that a significant amount of residual heat from a first printed pixel is still present when heat is applied to the next adjacent pixel. The use of this residual heat improves the printing efficiency. An elliptical beam may have its major axis in the scan direction to facilitate overlap. Printing may be effected to a non-square grid with more information, or a repetition of information, a set number of times in the scan direction. The power applied to a pixel may be adjusted depending on the darkness of previous adjacent printed pixels.

Abstract: A laser printer provides a photoreceptor and a laser which produces an optical beam. A modulator is coupled to the laser and is responsive to binary data values to apply modulation signals to the laser to cause an image-wise modulation of the optical beam. Scan apparatus repetitively scans the optical beam across the photoreceptor to induce an image-wise charge state thereon. The scan apparatus causes, for one of the binary values, a variation in charge states corresponding to the one binary value across the photoreceptor. A function generator applies correction signals to the modulator to alter the optical beam in such a manner as to substantially prevent the variation of charge states. The function generator either causes a modulation of the voltage bias applied to the laser or modulates its pulse width output.

Abstract: Fine pulse width modulation (PWM) adjustments in the output of a laser printer are accomplished by receiving values from a bit map and modifying the values in accordance with values in a lookup table (LUT). The lookup table is subdivided into a plurality of blocks, and a selection of the blocks is made in accordance with external values. This allows the output of a pulse width modulation circuit to be adjusted to a precision that is greater than that afforded by the bit size of the values from the bit map. The use of plural blocks in the lookup table permits adjustments in the output of the pulse width modulation circuit in accordance with external factors such as relative humidity, sensitivity of an optical photoreceptor, and developer life.

Abstract: A raster output scanner for use in an electrophotographic printer uses two light sources to create two scan lines on a photoreceptor simultaneously. The two light sources are operated in an alternating fashion, and the intensity of the light sources is monitored by a single sensor. The sensor is associated with a reflex-based exposure control system, which operates to shut off a particular light source when the exposure created by the light source reaches a threshold level.

Abstract: An image processing apparatus includes a first delay generation circuit, requiring no high-frequency clocks, for obtaining a pixel formation start timing signal from a digital input signal, a second delay generation circuit, requiring no high-frequency clocks, for obtaining a pixel formation end timing signal from the digital input signal, and a unit for obtaining a pixel formation interval signal from the pixel formation start and end timing signals.

Abstract: Information or data in the form of a mathematical representation of an area to be covered by a desired gray level, is sent, for example in floating point format, to a printer, e.g. a laser printer, for processing by the printer processor. The area to be covered is converted to a representation of pixels with the gray level converted to a digital value such as an eight bit value. Supercell representations with a gray level threshold matrix is provided, with each of the supercell array cells having threshold levels associated therewith whereby if the selected gray level is either above or below the threshold, one of print/no-print conditions are met for that pixel. Alternatively, if the level is the opposite and greater than a preselected range of values, the print/no-print condition will be opposite.

Abstract: The present invention discloses a dynamic control of a drive circuit to a diode laser used in a raster output scanning system. In the prior art, the binary serial stream input to a diode laser operates on the laser to pulse the laser on when a "one" input is applied, the laser staying on when the first one input is immediately followed by successive one inputs. The first on pixel creates an exposure at an image plane which is less than uniform due to the characteristics of the drive circuit due to the overshoot or undershoot characteristics of the drive circuit. The second and succeeding pixels following the first pixel turned on will be at a maximum exposure value and hence will have an undesirable exposure contrast with the first pixel.

Abstract: An image forming apparatus which can form gray-scale images comprises a pulse width modulation device for outputting a pulse width modulation signal according to image data, a light emitting device for emitting modulated light in response to the pulse width modulation signal outputted from the pulse width modulation device, a detecting device for detecting quantity of the modulated light, a current control device for controlling, at a time when the light emitting device emits modulated light continuously, current to be supplied to the light emitting device in accordance with the quantity of light detected by the detecting device, and a condition control device for controlling a condition of the pulse width modulation device according to the quantity of light detected by the detecting device at a time when the light emitting device emits the modulated light according to the pulse width modulation signal.

Abstract: Image forming apparatus and method for forming half tone images by pulse width modulating multi-valued image signals comprises first and second pattern signal generators which generate pattern signals each having the same period and a phase shifted from each other, first and second pulse width modulators for pulse width modulating said image signals using the first and second pattern signals, respectively, a selector for selecting either of the first and second pulse width modulated signals and a controller for controlling the selector to obtain a screen angle of 45.degree..Further, image forming apparatus and method which realizes a screen angle .theta. wherein tan .theta. is represented by a rational number.

Abstract: An image forming apparatus including a bit map data generating section for generating binary dot data for each color from image data, an image memory for storing the dot data, an edge dot discriminating section for discriminating edge dots positioned in an edge section, such as a curved-line section, a slanted-line section of characters, graphics, photo images, etc. in dot data for black stored in the image memory, and a dot modulating circuit for modulating the dot data so that the edge dots and printing dots other than black ones become smaller than black printing dots other than the edge dots. With this arrangement, since linear tone can be obtained even in a section with a deep color, excellent tone can be obtained in multi-color printing such as full-color printing. Therefore, reproducibility of tone of binarized image data can be improved, and jaggedness in an edge section can be improved so as to have a smooth line.

Abstract: An image forming apparatus in which two delay time generators input data for two delay times, and a reference signal, and outputs two pulse signals having predetermined pulse-widths. A pulse generator generates a pulse signal based on the phase difference between the two output pulse signals. The pulse-width and pulse position of the generated pulse signal is arbitrarily controlled by the two output pulse signals.

Abstract: A method of processing image data to reproduce an image having good half-tone reproduction, sharpness, and details, through pulse modulation of a laser beam. In the method, the laser beam is turned on and off in accordance with the result of comparing an input image signal with a reference signal which has been frequency modulated in accordance with a shape feature of the input image signal. In the case of an image having low input contrast, the tone performance of an image output unit is improved by the mesh dots of the low spatial frequency. In the case of an image having high input contrast, an image having high sharpness and details is reproduced by the mesh dots of the high spatial frequency.

Abstract: The present invention is a an apparatus for enhancing the output along edges of charged area developed regions in a tri-level imaging system employing a pulse width and position modulated signal ROS for exposure. The invention enables the identification and selective alteration of video data used to drive the ROS so as to extend the developed regions by a selected amount and eliminate digitization artifacts present in the image to be printed. The extension of the charged area developed regions is accomplished by reducing or trimming the width of the exposure pulses in adjacent areas to enable development within a portion of those regions.

Abstract: Apparatus and method for digitally printing a finely detailed image using pulse width modulation (PWM) with improved productivity over the prior art. Many images, or portions of images, generated by printers utilizing PWM do not require that any of the pixels be exposed for the maximum time possible, but that a maximum exposure can be determined for a selected portion of the image, whether it is for a line, for a paragraph, or for a selected color, that can then be used to speed up the printing of that portion of the image. Thus, a less than full density exposure can be set as the maximum, and the scanning speed increased accordingly to shorten the overall time required for printing that portion of the image.

Abstract: In an image forming apparatus including a pulse-width modulating unit for subjecting an image-density signal to pulse-width modulation and an image-forming unit for forming an image in accordance with a pulse-width modulation signal outputted by the pulse-width modulating unit, an arrangement is provided such that the image is formed with a small number of lines when the image density is a low density, while the image is formed with a large number of lines when the image density is a medium/high density. In an example of the arrangement thereof, the pulse-width modulating unit has a unit for effecting modulation on the basis of a plurality of different modulation periods, and is provided with a selecting unit for selecting a modulation period of a pulse-width modulated wave to be outputted, in accordance with the image-density signal.

Abstract: An image forming apparatus comprising: a laser beam irradiating device for irradiating a laser beam onto a record support member; a storage device for storing image data composed of a plurality of dots; a detection device which reads out the image data from the storage device so as to detect whether or not dots to be subjected to light emission by the laser beam are arranged continuously; and a control device for controlling an irradiation period of the laser beam irradiating device to a smaller value when the detection device has detected that the dots to be subjected to light emission are arranged continuously.

Abstract: A graduation reproduction method in performing the halftone recording due to screen percentage by a light spot of a light beam with the light beam being intensity-modulated on the basis of digital image data in accordance with a binary recording technique. An illumination time value is reduced with respect to the normal illumination time value determined under a recording condition set to record a minimum recording dot on the recording medium. The reduced illumination time is set as a unit illumination time at the time of the recording of the halftone and the secondary scanning speed is reduced in correspondence with the rate of reduction of the unit illumination time relative to the normal illumination time value. Further, in the case that the recording operation is the screen percentage to be effected by the light spot only for the unit illumination time, the exposure is arranged so as not to be effected by the light spot, or arranged to be effected for the normal illumination time value.

Abstract: The raster scanning system of the present invention includes a beam generator which generates a beam of radiant energy in response to a drive signal. The drive signal comprising a series of pulses. The raster scanning system further includes a polygon having an overfilled facet design in which a plurality of facets are at least partially positioned in the optical path of the beam of radiant energy regardless of the rotational position of the polygon. The polygon being adapted to scan a spot across a beam receiving surface. Additionally the raster scanning system includes spot size correcting means for maintaining a constant spot size of the scanned spot by modulating the pulse width of the drive signal provided to the beam generator.

Abstract: The present invention is a an apparatus for enhancing the output along edges of discharged area developed regions in a tri-level imaging system employing a pulse width and position modulated signal ROS for exposure. The invention enables the identification and selective alteration of video data used to drive the ROS so as to extend the developed regions by a selected amount and eliminate digitization artifacts present in the image to be printed. The extension of the discharged area developed regions is accomplished by extending the width of, or adding separate, exposure pulses in adjacent areas to enable development within a portion of those regions.

Abstract: A laser printer includes a Resolution Enhancement driver for causing modulation of image edge pixels. The printer comprises a laser for discharging an electrophotographic surface in accordance with an applied modulation signal. A control processor applies modulation signals to the laser in accordance with received commands. A format controller determines if an image pixel resides at an edge of an image feature and, if so, selects a pixel modification to enhance a representation of the feature edge. The format controller, in conformance with the selected pixel modification, generates an encoded command to the control processor that enables the generation of an appropriate laser modulation signal.