Beam Generator Driving Means Patents (Class 347/132)
  • Patent number: 6219084
    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.
    Type: Grant
    Filed: September 1, 1999
    Date of Patent: April 17, 2001
    Assignee: Agfa-Gevaert
    Inventors: Bruno August Van Uffel, Johannes Stoffel Buyze
  • Patent number: 6195109
    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.
    Type: Grant
    Filed: February 23, 1999
    Date of Patent: February 27, 2001
    Assignee: Oki Data Corporation
    Inventor: Nobuo Wakasugi
  • Patent number: 6188420
    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.
    Type: Grant
    Filed: December 21, 1998
    Date of Patent: February 13, 2001
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Kuribayashi, Noboru Koumura, Yukio Nagase, Izumi Narita, Seiji Mashimo
  • Patent number: 6175375
    Abstract: An improved EP printer will automatically compensate for printer output darkness shift over the usage life of one or more components of the print engine. In many EP print engines, the printer output darkness without correction will gradually change as the components are used, and typically, the darkness will increase to an extent that is perceptible. The printer output darkness can be controlled using a EP operating point that changes certain operating parameters, such as the laser diode current, the duty cycle of the video data signals driving the laser diode, and other voltage parameters including the charge roller voltage, or the developer bias voltage. It is desirable to make adjustments over the usage life of these components, so as to maintain the initial printer output darkness throughout the life of the major system components.
    Type: Grant
    Filed: January 25, 2000
    Date of Patent: January 16, 2001
    Assignee: Lexmark International, Inc.
    Inventors: Douglas Anthony Able, Cyrus Bradford Clarke, Mark Edwin Kirtley Lund, Daniel George Mlejnek, George Peter Olson, Gregory Lawrence Ream, Thomas Campbell Wade
  • Patent number: 6144393
    Abstract: An image forming apparatus includes an exposing unit for performing exposure by scanning a beam to a photosensitive belt to form an electrostatic latent image, a developing unit for forming a toner image by supplying liquid toner to the electrostatic latent image formed by the exposing unit, a sensor for detecting the position of the toner image formed on the photosensitive belt, and a controller for calculating a positional error by comparing the position detected by the sensor with an established reference position and controlling exposure performed by the exposing unit to correct the calculated positional error. Thus, since errors between the established scanning position and the actual scanning position are automatically corrected during scanning, the scanning can be performed more precisely and conveniently.
    Type: Grant
    Filed: June 30, 1998
    Date of Patent: November 7, 2000
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Hee-kook Kwak
  • Patent number: 6108018
    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.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: August 22, 2000
    Assignee: Canon Kabushiki Kaisha
    Inventors: Izumi Narita, Kenji Muto
  • Patent number: 6016156
    Abstract: The invention avoids an increase in the number of parts and components which form an apparatus for forming an image, and hence, prevents a main body of the image forming apparatus from completed in a large size.
    Type: Grant
    Filed: February 10, 1998
    Date of Patent: January 18, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Toshio Urakawa
  • Patent number: 6014161
    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.
    Type: Grant
    Filed: January 31, 1997
    Date of Patent: January 11, 2000
    Assignee: Hewlett-Packard Company
    Inventors: B. Mark Hirst, Mark Wibbels
  • Patent number: 5973709
    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.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: October 26, 1999
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Jiro Tanuma, Norio Nakajima, Shinichi Katakura
  • Patent number: 5959650
    Abstract: In a method for forming a digital image with use of electrophotographic process wherein the gradation is expressed by changing the laser intensity according to image information, at least one of the surface electric potential V.sub.O of photoconductor and the development bias electric voltage V.sub.B is controlled, and the laser intensity is controlled for gradation correction to compensate a change in gradation due to the control of V.sub.O and V.sub.B.
    Type: Grant
    Filed: August 10, 1993
    Date of Patent: September 28, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5943087
    Abstract: A laser beam printing machine according to the present invention includes a polygon mirror motor; a first control circuit which generates, in response to an error in rotation of the polygon mirror motor, a control signal which bring about the rotation of the polygon mirror motor to a target rpm and performs a PWM control; an output circuit which receives data for printing and, in response to the received data, outputs data for controlling a laser beam; a voltage controlled oscillator which generates clock pulses for determining the transmission timing of the data from the output circuit; and a second control circuit which controls, in response to the control signal, a control voltage of the voltage controlled oscillator to follow up the rotation fluctuation of the polygon mirror motor.
    Type: Grant
    Filed: September 10, 1996
    Date of Patent: August 24, 1999
    Assignee: Rohm Co., Ltd.
    Inventors: Emika Kataoka, Noboru Takizawa
  • Patent number: 5872587
    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.
    Type: Grant
    Filed: October 18, 1993
    Date of Patent: February 16, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Atsushi Fujita, Kenichi Wada, Tomohiko Masuda
  • Patent number: 5815025
    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.
    Type: Grant
    Filed: October 20, 1995
    Date of Patent: September 29, 1998
    Assignee: Ricoh Company, Ltd.
    Inventor: Shinichi Kubota
  • Patent number: 5754215
    Abstract: In the present invention, data with regard to passing time of respective sides of a polygon mirror when a polygon motor is in a predetermined rotating condition is stored in a memory at the respective addresses, the memory is accessed in response to the rotation of the polygon mirror and the data on the side (reflection face) performing the scan on a photo sensitive drum are successively generated while corelating with the scan, a difference between a target rotating amount under a proper standard rotation of a particular side and an actual rotating amount of the particular side is obtained time to time for respective sides of the polygon mirror, which depends on the processing accuracy of the respective sides, thereby even the polygon motor having a poor processing accuracy can be controlled at the standard rotation so that the scanning speed by the rotation is brought about to a target value like a polygon motor having a high processing accuracy.
    Type: Grant
    Filed: November 8, 1994
    Date of Patent: May 19, 1998
    Assignee: Rohm Co., Ltd.
    Inventors: Emika Kataoka, Noboru Takizawa
  • Patent number: 5739842
    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.
    Type: Grant
    Filed: February 27, 1997
    Date of Patent: April 14, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Kazuyuki Murata
  • Patent number: 5734406
    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.
    Type: Grant
    Filed: April 7, 1994
    Date of Patent: March 31, 1998
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Yukio Nakamura, Hiroshi Furuya, Takashi Ishizaki, Takeyuki Yanagibashi
  • Patent number: 5719613
    Abstract: In a apparatus for forming a digital image with use of electrophotographic process wherein the gradation is expressed by changing the laser intensity according to image information, at least one of the surface electric potential V.sub.O of photoconductor and the development bias electric voltage V.sub.B is controlled, and the laser intensity is controlled for gradation correction to compensate a change in gradation due to the control of V.sub.O and V.sub.B. A ratio of variable differences of potential in the apparatus, (V.sub.B -V.sub.I)/(V.sub.O -V.sub.I), is kept constant to control the gamma characteristic in the apparatus.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: February 17, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5682192
    Abstract: To create a latent electrostatic gray scale image on a charge receptor, a gray scale generator determines a charge distribution for a unit cell having at least two pixels. A charge manager then determines the amount of charge to be placed in each pixel. More specifically, the charge amount for a first ON pixel in the unit cell is assigned a relative full charge amount. The charge amount in each succeeding ON pixel is determined such as to ensure faithful reproduction of gray scale for any given ratio of pixel size to charge receptor thickness. To increase the developability in proportion to the gray scale, the charge manager manages the charge amount of succeeding ON pixels to be a smaller amount than the first ON pixel.
    Type: Grant
    Filed: December 9, 1993
    Date of Patent: October 28, 1997
    Assignee: Xerox Corporation
    Inventor: Inan Chen
  • Patent number: 5668587
    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.
    Type: Grant
    Filed: August 11, 1995
    Date of Patent: September 16, 1997
    Assignee: Xerox Corporation
    Inventors: Thomas J. Hammond, George A. Charnitski
  • Patent number: 5648810
    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.
    Type: Grant
    Filed: July 2, 1992
    Date of Patent: July 15, 1997
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Jiro Tanuma, Katsuyuki Ito, Shinichi Katakura, Nobuo Wakasugi, Kazuhiko Nagaoka, Toshikaru Ito
  • Patent number: 5633669
    Abstract: In a digital image forming apparatus, the intensity or the pulse width of laser beam exposure is modulated according to image signals of a document detected by a sensor. A peak waveform having a peak is generated in each light-emitting period of laser beam. For example, and a signal having a peak is synthesized with the image signals to generate the peak waveform. Thus, the laser is driven according to the peak waveforms so that the exposed portions on a photoconductor in correspondence to the peaks are exposed with a larger quantity of light at low densities. Then, the amount of the gamma correction can be decreased and the gradation characteristic can be stabilized.
    Type: Grant
    Filed: January 26, 1994
    Date of Patent: May 27, 1997
    Assignee: Minolta Co., Ltd.
    Inventors: Yoshinobu Hada, Masaki Tanaka, Kazuyuki Fukui, Kouichi Etou
  • Patent number: 5600363
    Abstract: An optical print head in an image forming apparatus includes linearly arranged blocks and integrated circuits for driving disposed at one or both ends of the line of blocks. Each of the blocks includes a plurality of light emitting diodes. Positionally corresponding light emitting diodes in each block are connected to one of a plurality of meandering individual signal lines which are connected to the integrated circuits and each block is further connected to a corresponding common signal electrode to which power is selectively applied, thereby making possible illumination and drive of light emitting diodes in each block. The head may include a housing containing the blocks, individual signal lines and common signal electrodes and further include a flexible substrate located outside of the housing connected to and supplying power to the common signal electrodes.
    Type: Grant
    Filed: November 3, 1993
    Date of Patent: February 4, 1997
    Assignee: Kyocera Corporation
    Inventors: Toshihiro Anzaki, Yasuo Nishiguchi, Moriyuki Arai, Shunji Murano, Sadayuki Orito, Yuuji Kurazono
  • Patent number: 5592207
    Abstract: A laser printer can record high definition and high quality images without requiring any increase of electrical and mechanical design precision for increasing a scanning line density thereof. The laser beam is deflected in a primary scanning direction and a subsidiary scanning direction. With such scanning, an artificial scanning line along an edge of a recording image can be established for accurately recording an oblique line, a curved line, a barbel portion of a character, a half-tone image or so forth.
    Type: Grant
    Filed: September 16, 1992
    Date of Patent: January 7, 1997
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Shinya Kobayashi, Akira Arimoto, Hiroo Fujisaki, Susumu Saito
  • Patent number: 5488404
    Abstract: A plurality of light-emitting diode chips (2) densely packed in the form of rows is associated with driver chips (34) and associated drive chips (3) on both sides. The printing information is supplied from a printer control (6) via a bus system (4, 4' and 5, 5'). Each light-emitting diode chip is subdivided into n groups of light-emitting diodes (for example LED1, LED3, LED5 . . . LED31 and LED98, LED100 . . . LED128), which are arranged geometrically offset with respect to one another transversely to the main direction of the diode row. Each drive chip contains a switching unit (32) for generating internal sequence control signals (for example SWE1, SWE2, I-CLK) and n part-circuits (33/0 to 33/3) associated with the n groups of light-emitting diodes for the simultaneous processing of the printing information into temporally staggered drive signals (DS).
    Type: Grant
    Filed: May 23, 1994
    Date of Patent: January 30, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventors: Friedrich Fleck, Klaus-Dieter Jorgens
  • Patent number: 5477257
    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.
    Type: Grant
    Filed: November 10, 1992
    Date of Patent: December 19, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Kazuyuki Murata
  • Patent number: 5473359
    Abstract: The laser beam printer apparatus can superimpose adding printing data, which is different from printing data, on printing data after bit map image data is expanded to printing data or while bit map image data is expanding. Adding printing data is synthesized with printing data at a predetermined period on basis of a clock supplied from either a main controlling unit or an image forming control section. Therefore, new printing data such as symbols and marks can be simultaneously outputted without newly remaking printing data.
    Type: Grant
    Filed: September 21, 1993
    Date of Patent: December 5, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Junji Yamada
  • Patent number: 5453773
    Abstract: In an electrophotographic image forming apparatus including a charger for electrically charging the photoconductor to a predetermined initial electric potential, a laser projects a light onto the photoconductor so as to form an electrostatic latent image thereon, and a developing device develops the latent image with toner so as to form a toner image thereon. Further, a charger controller controls the charger based on a detection result of a detector for detecting a state of the photoconductor so that the initial electric potential of the photoconductor changes in a predetermined range, and a selection controller selects one of the plurality of gradation correction data stored in a storage unit based on the detection result of the detector when the initial electric potential of the photoconductor is an upper or lower limit value of the predetermined range.
    Type: Grant
    Filed: November 27, 1991
    Date of Patent: September 26, 1995
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Yoshihiro Hattori, Kazuyuki Fukui, Takanobu Yamada, Yoshikazu Naito
  • Patent number: 5438437
    Abstract: An electrophotographic color image forming machine registers which a second color toner image on a first color toner image which has been previously formed on an image carrier to form a color image. The registered images are then transferred onto a recording sheet. The machine includes control apparatus that includes first and second exposure control modulators which respectively control an exposure amount of at least one of the first color toner images and the second color toner image. A smoothing processor controls at least one of a size and a position of at least one of the first and second color toner dot images within each of a plurality of pixels and a discriminator determines whether one of the size and the position of the dot image should be controlled.
    Type: Grant
    Filed: October 13, 1992
    Date of Patent: August 1, 1995
    Assignee: Konica Corporation
    Inventors: Yoshimi Mizoguchi, Hiroshi Ishii, Kiyoshi Kimura, Masakazu Fukuchi, Makoto Takeda, Hiroyuki Maruyama, Yasuhiko Yamaguchi, Kenji Taki, Masashi Akamatsu, Takao Kurohata
  • Patent number: 5412408
    Abstract: An image recording apparatus records an image on a recording medium by scanning a spot light beam in accordance with image information. The apparatus has a storage device for storing the image information corresponding in amount to at least three sub-scan lines, and a light intensity controller for increasing and decreasing the intensity the light beam in accordance with the contents of the storage device relative to a standard intensity. A light beam of the standard intensity satisfies a relation of 1.8.ltoreq.d/p where d represents a light beam diameter (defined as the diameter at which the light beam intensity lowers to 1/e.sup.2 (e: base of the natural logarithms) of the intensity at the light beam center, and p represents an interval between respective scan lines.
    Type: Grant
    Filed: May 21, 1993
    Date of Patent: May 2, 1995
    Assignee: Canon Kabushiki Kaisha
    Inventors: Michio Itoh, Hiromichi Yamada
  • Patent number: 5402157
    Abstract: A voltage is selectively applied between two electrodes (emitter and gate) disposed at a short distance to create an intense electric field between the electrodes. Electrons emitted by the field emission are accelerated by the intense electric field and collide against a fluorescent layer so that light can be emitted from portions of the fluorescent layer. With a recording head of the above construction, an electrostatic latent image is formed on a photosensitive drum.
    Type: Grant
    Filed: March 30, 1993
    Date of Patent: March 28, 1995
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Nagato, Yuzo Koike, Shuzo Hirahara, Masafumi Mori