Bias Control Patents (Class 399/55)
  • Patent number: 10437190
    Abstract: An AC measuring circuit measures a magnitude of an alternating current flowing through a bias applying circuit synchronized with a cycle of an AC voltage in a developing bias voltage. A control unit changes a level of the AC voltage in the developing bias voltage, and executes a developing bias adjustment process for setting a level of the AC voltage based on the level of the AC voltage when the leakage current detecting circuit detects the direct current. The control unit, when a measurement by the AC measuring circuit during execution of a developing process exceeds a predetermined allowable value, executes a warning process to prompt execution of the developing bias adjustment process, or the control unit executes the developing bias adjustment process to update the level of the AC voltage.
    Type: Grant
    Filed: May 22, 2018
    Date of Patent: October 8, 2019
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Kensuke Fujihara
  • Patent number: 10394156
    Abstract: An image formation apparatus according to an embodiment includes: an image carrier; a charging member facing the image carrier; a developer carrier facing the image carrier; and a controller that controls a rotating operation of the image carrier, application of a charge voltage to the charging member, and application of a development voltage to the developer carrier. In a first period, the controller sets an absolute value of a voltage difference between a DC component of the charge voltage and a DC component of the development voltage to a first value to develop a latent image on the image carrier. In a second period after the first period, the controller sets the absolute value of the voltage difference to a second value smaller than the first value.
    Type: Grant
    Filed: July 12, 2018
    Date of Patent: August 27, 2019
    Assignee: Oki Data Corporation
    Inventor: Fumitaka Ozeki
  • Patent number: 10386778
    Abstract: In an image forming apparatus, a neutralizing portion provided on an image forming unit is configured to emit a neutralizing light toward a front irradiation position between a developing portion and a first transfer portion 15, on a photoconductor drum of an image forming unit, and a rear irradiation position between the first transfer portion and a cleaning portion, on the photoconductor drum of the image forming unit. A light quantity limiting portion is configured to limit an amount of light irradiated on the front irradiation position of the image forming unit, such that the amount of light is less than amounts of light irradiated on other front irradiation positions.
    Type: Grant
    Filed: November 26, 2018
    Date of Patent: August 20, 2019
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Yosuke Saito
  • Patent number: 10353320
    Abstract: Example implementations provide a method of controlling an ink developer used in electro-photography; the method comprising, following cessation of printing, varying a plurality of voltages associated with movement of ink within the ink developer at temporally disparate times.
    Type: Grant
    Filed: August 19, 2015
    Date of Patent: July 16, 2019
    Assignee: HP Indigo B.V.
    Inventors: Eric G. Nelson, Yoav Nachmias, Michel Assenheimer, Vitaly Portnoy, Amiran Lavon
  • Patent number: 10295930
    Abstract: An applied voltage control device includes a potential difference determiner and an applied voltage controller. The potential difference determiner determines a potential difference between a maximum alternating current development voltage and a minimum alternating current development voltage, depending on a developing potential that is an absolute value of a difference between an average electric potential of an alternating current development and an electric potential of a latent image, so as to maintain a constant maximum voltage of a developing bias in the alternating current development. The applied voltage controller controls an alternating current development voltage, applied to move developer from a developer bearer to the latent image, so as to obtain the potential difference determined by the potential difference determiner.
    Type: Grant
    Filed: October 12, 2016
    Date of Patent: May 21, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Emiko Shiraishi, Hiroaki Kuwabara
  • Patent number: 10151997
    Abstract: An image forming apparatus includes first and second image forming units each having an image bearing member and an electrification portion. A developing bias application portion applies a common developing bias to first and second developer bearing members. A controller controls a second electrification bias application portion so as to have a voltage value of a second electrification bias applied to a second electrification portion in a first period different from that in a second period such that an absolute value of a potential difference between a surface potential of a second image bearing member and the common developing bias applied to the second developer bearing member in the first period is smaller than that in the second period.
    Type: Grant
    Filed: November 29, 2016
    Date of Patent: December 11, 2018
    Assignee: Canon Kabushiki Kaisha
    Inventor: Hideaki Suzuki
  • Patent number: 10133225
    Abstract: An image forming apparatus includes a developing roller, a voltage applying part, a direct current correcting part and a correction switching part. The developing roller supplies a toner to an image carrier. The voltage applying part applies a superimposed voltage of an alternating current voltage and a direct current voltage to the developing roller. The direct current correcting part corrects the direct current voltage on the basis of variation of an alternating current flowing between the voltage applying part and the developing roller. The correction switching part switches the direct current voltage correcting part between an operating state and a non-operating state.
    Type: Grant
    Filed: June 12, 2017
    Date of Patent: November 20, 2018
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Tatsuya Nakagawa
  • Patent number: 10101705
    Abstract: The present invention discloses a process cartridge and a power supply method therefor. The process cartridge is detachably mounted in an electrophotographic image forming apparatus, comprising a developing member rotatably mounted in the process cartridge and a voltage generating unit, the voltage generating unit is electrically connected to the conductive contact and the developing member. The process cartridge supplies power by using a data line, and the power supply method comprises: providing a conductor, and transmitting electric energy on the data line to the voltage generating unit by using the conductor. When the process cartridge is mounted in an electrophotographic image forming apparatus that outputs a DC bias voltage, because the voltage generating unit can generate an AC bias voltage, the process cartridge can work in an electrophotographic image forming apparatus that outputs a DC bias voltage and also in an apparatus that outputs an AC bias voltage.
    Type: Grant
    Filed: May 15, 2017
    Date of Patent: October 16, 2018
    Inventors: Xueping Ding, Junqing Liu, Zhengjun Zhou, Jizhong Wang
  • Patent number: 9964889
    Abstract: An image forming apparatus includes: a development unit configured to develop, using a developer, the electrostatic latent image formed on an image carrier and form a developer image in a region where the image carrier faces the development unit; a supply unit configured to output a supply bias, supply the developer to the development unit, and collect the developer from the development unit; a reception unit configured to receive image data; an analysis unit configured to analyze a non-image region where the developer image is not formed from the image data; and a control unit configured to control the supply bias in accordance with a length of the non-image region where the developer image is not formed in a rotation direction of the image carrier.
    Type: Grant
    Filed: March 2, 2016
    Date of Patent: May 8, 2018
    Assignee: Canon Kabushiki Kaisha
    Inventor: Michio Sugano
  • Patent number: 9851671
    Abstract: An example method of controlling a printing process in accordance with aspects of the present disclosure includes controlling an optical density of a printed image such that the optical density is increased for a predetermined portion of a leading edge of a page.
    Type: Grant
    Filed: January 31, 2014
    Date of Patent: December 26, 2017
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Noam Parvin, Erez Kopel, Idan Federman, Gregory Braverman, Moshe Birenboim
  • Patent number: 9835973
    Abstract: An image forming apparatus includes an image bearing member on which a latent image is formed, a developer carrying member for developing the latent image, and an electroconductive regulating member for regulating a layer thickness of the developer in contact with the developer carrying member. A voltage source applies, to the electroconductive regulating member, a voltage of the same polarity as a polarity of the developer on a surface of the developer carrying member at least during a developing operation. The developer remaining on the surface of the image bearing member, after a developer image formed on the image bearing member is transferred, is collected by the developer carrying member.
    Type: Grant
    Filed: February 23, 2016
    Date of Patent: December 5, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Gosuke Goto, Satoshi Sunahara, Akihisa Matsukawa
  • Patent number: 9798281
    Abstract: An image forming apparatus includes an image bearing member to which lubricant is supplied; a toner image forming section; and a patch image forming section and a control section configured to control the toner image forming section and the patch image forming section such that a first development condition for forming the patch image and a second development condition for forming the toner image are different from each other.
    Type: Grant
    Filed: July 29, 2016
    Date of Patent: October 24, 2017
    Assignee: KONICA MINOLTA, INC.
    Inventor: Atsuto Hirai
  • Patent number: 9791799
    Abstract: An image forming apparatus includes a charging roller and a developing voltage application portion. The charging roller is in contact with a rotating image carrier to charge the image carrier. The developing voltage application portion applies a developing bias voltage including an AC component to a developing roller in a developing portion, when the image carrier is in a rotation state with no image. The rotation state with no image indicates a state in which the charged image carrier rotates with no electrostatic latent image being formed thereon. The developing portion supplies toner containing an external additive to the image carrier.
    Type: Grant
    Filed: April 26, 2016
    Date of Patent: October 17, 2017
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Kiyotaka Kobayashi
  • Patent number: 9785098
    Abstract: In an image forming apparatus including a power source for forming a secondary-transfer electric field at a secondary-transfer position and for forming a primary-transfer electric field at a primary-transfer position by applying a voltage to a transfer member to pass a current through a constant-voltage element, a potential of an image portion is controlled depending on a detection result of a detecting member.
    Type: Grant
    Filed: March 9, 2016
    Date of Patent: October 10, 2017
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tohru Nakaegawa, Masanori Shida
  • Patent number: 9599925
    Abstract: An image forming apparatus includes: an image carrier; an image forming unit configured to form, on the image carrier, an electrostatic latent image; a developing unit including a toner carrier configured to develop, on the image carrier, a toner image corresponding to the electrostatic latent image; an application unit configured to apply a lubricant onto the image carrier; a calculation unit configured to calculate an image portion ratio representing a ratio of a toner sticking region to the electrostatic latent image or the toner image; and a control unit configured to cause the lubricant mixed into the developing unit to stick to the toner carrier, and change, depending on the image portion ratio, an amount of the lubricant caused to stick to a non-image-formation region which is a region on the image carrier and in which the electrostatic latent image or the toner image is not formed.
    Type: Grant
    Filed: March 30, 2016
    Date of Patent: March 21, 2017
    Assignee: KONICA MINOLTA, INC.
    Inventor: Takeshi Maeyama
  • Patent number: 9501017
    Abstract: An image forming apparatus includes a conversion unit configured to convert image data based on a conversion condition, an image forming unit configured to be controlled based on an image forming condition, and to form an image based on the converted image data, a measurement unit configured to measure a plurality of measurement images, a first determination unit configured to determine the image forming condition based on a first measurement result of a first measurement image, a generation unit configured to generate the conversion condition based on second measurement results of second measurement images and a feedback condition, and a second determination unit configured to determine the feedback condition based on the first measurement result. The image forming unit sets the determined image forming condition in next timing. The conversion unit updates the conversion condition after the generation unit generates the conversion condition and before the next timing.
    Type: Grant
    Filed: September 16, 2015
    Date of Patent: November 22, 2016
    Assignee: Canon Kabushiki Kaisha
    Inventor: Yasuhito Shirafuji
  • Patent number: 9488930
    Abstract: When rotation speed of second rotator is greater than or equal to a threshold previously determined, first control portion causes first generation portion to generate a first potential difference that enables toner in a predetermined amount to be transferred from first rotator to second rotator, and causes second generation portion to generate a second potential difference that enables the toner in the predetermined amount to be transferred from second rotator to a electrostatic latent image. When the rotation speed is less than the threshold, second control portion causes first generation portion to generate a third potential difference that enables the toner in an amount exceeding the predetermined amount to be transferred from first rotator to second rotator, and causes second generation portion to generate a fourth potential difference that enables the toner in the predetermined amount to be transferred from second rotator to the electrostatic latent image.
    Type: Grant
    Filed: November 16, 2015
    Date of Patent: November 8, 2016
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Yoshinobu Yoneima
  • Patent number: 9479057
    Abstract: A circuit arrangement for supplying an output current to a load which is useable in power supplies and is connectable in parallel to other circuit arrangements, wherein effects of component tolerances on a uniform working load are avoided.
    Type: Grant
    Filed: May 6, 2010
    Date of Patent: October 25, 2016
    Assignee: Siemens Aktiengesellschaft
    Inventors: Michael Cyron, Arnold Klamm
  • Patent number: 9459554
    Abstract: An image formation apparatus includes: an image carrier; an exposure unit; a developer container part; a developer supply unit; a development unit; a remaining amount detector which detects a remaining amount of the developer in the container part; a development voltage application unit which applies a development voltage to the development unit; a supply voltage application unit which applies a supply voltage to the supply unit; and a voltage controller which controls the development voltage and the supply voltage. When the remaining amount of the developer detected by the remaining amount detector is reduced to a predetermined first threshold or less, the voltage controller makes an absolute value of a difference between the development voltage and the supply voltage smaller than that used when the remaining amount of the developer is larger than the first threshold.
    Type: Grant
    Filed: February 18, 2016
    Date of Patent: October 4, 2016
    Assignee: Oki Data Corporation
    Inventor: Yoshio Niijima
  • Patent number: 9459553
    Abstract: An image forming apparatus includes a first roller, a second roller, a first voltage applying section, and a control section. An electrostatic latent image is formed on the first roller. The second roller is located opposite to the first roller with a first gap therebetween. The first voltage applying section applies voltage to the second roller. The control section determines a first voltage value to be applied to the second roller during development of the electrostatic latent image. The control section determines a first distance non-uniformity value indicating a degree of non-uniformity of a distance across the first gap. The control section determines a first indicator value by increasing voltage applied to the second roller in stages and performing electrical discharge measurement at each of the stages. The control section determines the first voltage value based on the first distance non-uniformity value and the first indicator value.
    Type: Grant
    Filed: July 31, 2015
    Date of Patent: October 4, 2016
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Kensuke Fujihara
  • Patent number: 9442415
    Abstract: An image formation apparatus includes an image carrier; a charge member; an exposure unit; a development member; a measurement unit that measures a stop time period when a rotation of the image carrier is being stopped, or a physical amount that varies as the stop time period increases; a setting unit that sets a polarity of an initial voltage to be applied to the development member, the polarity being determined based on the stop time period or the physical amount measured by the measurement unit; and a power source unit that applies the initial voltage with the polarity set by the setting unit to the development member, at rotation start time of the image carrier.
    Type: Grant
    Filed: October 19, 2015
    Date of Patent: September 13, 2016
    Assignee: Oki Data Corporation
    Inventor: Kenichi Funatsu
  • Patent number: 9400447
    Abstract: An image forming apparatus includes a first power source configured to supply charging voltage to a first charging unit, and a second power source configured to supply predetermined voltage to at least one of a second charging unit, a second developing member, and a second transfer unit. The first and the second power sources are grounded via a common resistor component. When the second power source in a state of supplying no voltage or supplying voltage lower than the predetermined voltage at a first timing starts supplying the predetermined voltage while the first power source is supplying the charging voltage, a control unit causes a separating mechanism to move a first developing member to a separation position before a second timing at which an area of a first photosensitive member that is at a charging position at the first timing reaches a developing position.
    Type: Grant
    Filed: October 16, 2015
    Date of Patent: July 26, 2016
    Assignee: Canon Kabushiki Kaisha
    Inventor: Shinsuke Kobayashi
  • Patent number: 9348256
    Abstract: An image forming apparatus includes a detachably mountable developing device including a developer container, a developer carrying member, a feeding member, provided in contact with the developer carrying member, for supplying the developer to the developer carrying member, and a developer regulator; and a voltage device capable of applying to the developer carrying member and the developer regulator respective voltages different from each other. The image forming apparatus carries out, when a fresh developing device is mounted, an initial operation in which the developer carrying member is rotated. In the initial operation, the voltage device applies, to at least one of the developer carrying member and the developer regulator, a voltage for the initial operation which is different from the voltage for normal image forming operation, so as to urge a material applied to the developer carrying member in the fresh developing device toward the developer regulator from the developer carrying member.
    Type: Grant
    Filed: March 6, 2015
    Date of Patent: May 24, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Yoshihiro Mitsui, Kodai Hayashi, Hisashi Taniguchi, Shuhei Kawasaki
  • Patent number: 9335665
    Abstract: An image forming apparatus includes an alternating transformer that splits an alternating voltage into a first alternating voltage and a second alternating voltage, a developer bias application unit, an alternating voltage shutoff unit, and a discharge starting voltage measurement unit. The developer bias application unit applies a pulsed sleeve roller voltage composed of a first alternating voltage superimposed on a first direct voltage to a sleeve roller and also applies a second alternating voltage and a second direct voltage separately to a magnetic roller in order to apply a pulsed magnetic roller voltage composed of the second alternating voltage superimposed on the second direct voltage. The alternating voltage shutoff unit stops applying the second alternating voltage to the magnetic roller. The discharge starting voltage measurement unit increases the alternating voltage of the alternating transformer to measure the discharge starting voltage between the sleeve roller and magnetic roller.
    Type: Grant
    Filed: June 24, 2015
    Date of Patent: May 10, 2016
    Assignee: KYOCERA DOCUMENT SOLUTIONS INC.
    Inventor: Kensuke Fujihara
  • Patent number: 9304432
    Abstract: An image forming apparatus includes an image carrier, a developing device, a bias applying unit, a leak detecting unit, a bias controller and a leak detection controller. The developing device includes a magnetic roller and a developer layer. The bias applying unit applies development biases to the magnetic roller and the developing roller. The leak detecting unit detects a leak generated between the image carrier and the developing roller or a leak generated between the developing roller and the magnetic roller. The leak detection controller performs a leak detecting operation for detecting the value of an inter-peak voltage of the alternating current voltage of the development bias applied to the developing roller, at which the leak is generated, while changing the inter-peak voltage at a time different from that during the developing operation.
    Type: Grant
    Filed: October 6, 2014
    Date of Patent: April 5, 2016
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Tamotsu Shimizu, Yukihiro Mori
  • Patent number: 9250563
    Abstract: An image forming apparatus includes an image carrier that rotates, a latent image forming unit that forms an electrostatic latent image on the image carrier, a developing unit that develops the electrostatic latent image formed on the image carrier, with a developer including a toner and an external additive, a transfer unit that transfers an image developed on the image carrier to a recording material, a cleaning member that cleans a residue remaining on the image carrier after transfer, a supply unit that supplies a developing bias, which has an alternating-current component superimposed on a direct-current component, between the image carrier and the developing unit, and a setting part that increases a peak-to-peak value of the alternating-current component of the developing bias when a non-image region on the image carrier passes a developing region, in comparison to when an image region on the image carrier passes the developing region.
    Type: Grant
    Filed: September 18, 2014
    Date of Patent: February 2, 2016
    Assignee: FUJI XEROX CO., LTD.
    Inventor: Yasuhiro Funayama
  • Patent number: 9223248
    Abstract: An image forming apparatus according to the invention includes a light source, an image carrier, a developer carrier, a supply member, and a controller. The light source emits light in accordance with printing data. The image carrier carries on a surface thereof a latent image based on the emitted light out of the light source. The developer carrier develops the latent image carried on the image carrier. The supply member supplies a developer to the developer carrier. The controller controls a voltage between the developer carrier and the supply member in accordance with a light emitting amount of the light source at a prescribed use amount.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: December 29, 2015
    Assignee: Oki Data Corporation
    Inventors: Masahiro Kawano, Takeshi Ishii
  • Patent number: 9217951
    Abstract: An image forming apparatus includes an image carrier, a developing device, a bias applying unit, a leakage detecting unit, a bias control unit and a leakage detection control unit. The developing device includes a magnetic roller and a developing roller. The magnetic roller carries a developer layer by being rotated. The developing roller receives the toner from the developer layer and supplies the toner to the image carrier. The leakage detection control unit performs a leakage detecting operation of detecting a value of an inter-peak voltage, at which the leakage occurred. The leakage detection control unit simultaneously starts the leakage detecting operation for a plurality of developing devices and performs the leakage detecting operations of the developing devices in which leakage simultaneously occurred while switching the leakage detecting operations one by one if the leakage simultaneously occurs in a plurality of developing devices at an inter-peak voltage.
    Type: Grant
    Filed: March 10, 2015
    Date of Patent: December 22, 2015
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Masashi Fujishima, Yoshinobu Yoneima, Tamotsu Shimizu
  • Patent number: 9213269
    Abstract: There is provided a developing device including a first developing roller that is disposed to be rotatable with a desired distance set between the first developing roller and an outer circumferential surface of a rotatable latent image holding member, transports a developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape, and a second developing roller that is disposed to be rotatable with desired distances set between the second developing roller and the respective outer circumferential surfaces of the corresponding latent image holding member and the corresponding first developing roller at a position on the downstream side of the first developing roller in a rotation direction of the latent image holding member, transports the developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape.
    Type: Grant
    Filed: January 29, 2013
    Date of Patent: December 15, 2015
    Assignee: FUJI XEROX CO., LTD.
    Inventors: Masanori Kato, Nobumasa Furuya, Jun Abe, Sakae Yoshioka
  • Patent number: 9207558
    Abstract: An image forming apparatus includes photosensitive drums, charging devices, an exposure unit configured to expose surfaces of photosensitive drums to generate a non-image portion potential and expose the surfaces to generate an image portion potential, developing members configured to make a developer adhere to an area where the image portion potential is generated to form a developer image on the photosensitive drums, a control unit configured to control an intensity of the charging voltage, and an acquisition unit configured to acquire thicknesses of photosensitive layers of the respective plurality of photosensitive drums, wherein the control unit is configured to set the intensity of a charging voltage applied to the common charging devices according to a maximum thickness among the thicknesses acquired by the acquisition unit, and individually control the output of the first laser power for the photosensitive drum according to surface potentials of the charged photosensitive drums.
    Type: Grant
    Filed: May 15, 2013
    Date of Patent: December 8, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hideaki Hasegawa, Motoki Adachi, Takayoshi Kihara
  • Patent number: 9164417
    Abstract: An image forming apparatus of a representative configuration of the present invention includes a photosensitive drum, which carries an electrostatic latent image, and a developing sleeve, which carries a two-component developer and develops the electrostatic latent image on the photosensitive drum into a toner image. Moving directions of the photosensitive drum and the developing sleeve are opposite at an opposing portion in a developing device having a speed changing portion, which changes the driving speed of the developing sleeve, and a controller, which switches a target speed of the developing sleeve so that it is driven at a second velocity, before it is driven at the first velocity set in a lower speed mode, when the lower speed mode is executed in which the photosensitive drum is driven at a lower speed than in the normal image forming.
    Type: Grant
    Filed: April 24, 2013
    Date of Patent: October 20, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shinya Suzuki, Tadashi Fukuda
  • Patent number: 9146505
    Abstract: An image forming apparatus includes a photosensitive member, a charging device, an exposure device, a development device, a transfer device, a first driving device, a voltage application device, and a controller. The first driving device rotatably drives one of the photosensitive member and a combination of the photosensitive member and an intermediate transfer member. The voltage application device supplies a respective predetermined voltage to the charging device, the development device, and the transfer device. The controller controls the first driving device and the voltage application device. When the photosensitive member is stopped, both illumination from the exposure device and the transfer electrical field electrically discharge the surface of the photosensitive member.
    Type: Grant
    Filed: June 27, 2014
    Date of Patent: September 29, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeshi Yamashita, Yasuhiro Fujiwara
  • Patent number: 9057976
    Abstract: An image forming apparatus includes a control unit controlling first and second voltage application mechanisms and shifting a difference Vdif (=Vrs?Vdr) between Vrs and Vdr toward polarity opposite to normal charge polarity of a developer as S decreases, where S is an absolute value of a speed difference between a circumferential speed of an image bearing member, which rotates while bearing an electrostatic latent image and a circumferential speed of a developer bearing member, which rotates at a constant circumferential speed ratio with respect to the image bearing member to develop the electrostatic latent image while bearing the developer, Vdr is a voltage that the first voltage application mechanism applies to the developer bearing member, and Vrs is a voltage that the second voltage application mechanism applies to the developer supply member.
    Type: Grant
    Filed: October 23, 2013
    Date of Patent: June 16, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventors: Nobuyoshi Yoshida, Yoshihiro Mitsui, Kodai Hayashi, Hisashi Taniguchi
  • Patent number: 9052634
    Abstract: A developing apparatus includes a developer carrying sleeve for carrying a developer to a position opposing an image bearing drum. The sleeve is provided with a plurality of groove portions extending in an axial direction of the sleeve, and a developing bias voltage applying device for applying a developing bias voltage to the sleeve. The bias voltage applying device is capable of outputting, as the bias voltage, a voltage of a waveform having a cyclic period including an AC bias portion having an AC component and a DC component superimposed thereto, and a blank portion following the AC bias portion and consisting of a DC component. A width L (m) of the groove, a peripheral speed Vs (m/s) of the sleeve, and a duration t1 (s) of the blank portion in one cyclic period of the bias voltage satisfy L/Vs<t1.
    Type: Grant
    Filed: July 30, 2014
    Date of Patent: June 9, 2015
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Mitsuhiro Furukawa, Tomoyuki Sakamaki
  • Publication number: 20150139674
    Abstract: An image forming apparatus includes an electrostatic latent image bearer; a charger to charge a surface of the electrostatic latent image bearer; a power source to output a charging bias supplied to the charger; an electrostatic latent image writing unit to write an electrostatic latent image on the surface of the electrostatic latent image bearer charged by the charger; a developing unit including a developing member to develop the electrostatic latent image to obtain a toner image; a developing power source to output a developing bias supplied to the developing unit; a processor to adjust the charging bias output from the power source to a predetermined target value; and a storage unit to store an adjustment value algorithm.
    Type: Application
    Filed: November 12, 2014
    Publication date: May 21, 2015
    Inventors: Hiroyuki SUGIYAMA, Shigekazu KOGUCHI, Masahiko SHAKUTO, Shinji MINAMI, Tomoko TAKAHASHI, Yoshinori NAKAGAWA, Ryuji YOSHIDA, Taichi URAYAMA
  • Publication number: 20150139669
    Abstract: An image forming apparatus includes: a cartridge installing section in which a first cartridge and a second cartridge are selectively installable; and a controller. The first cartridge includes: a first case configured to contain a first developer; a first developing roller; and a first transport member configured to transport the first developer toward the first developing roller. The second cartridge includes: a second case configured to contain a second developer, an amount of the second developer being greater than an amount of the first developer; a second developing roller; and a second transport member configured to transport the second developer toward the second developing roller. The controller is configured to control a drive source to drive one of the first transport member and the second transport member.
    Type: Application
    Filed: November 14, 2014
    Publication date: May 21, 2015
    Inventor: Hikaru Yoshizumi
  • Patent number: 9037019
    Abstract: A developing device includes a developing roller, a magnetic roller, a capacitor, a transformer, and a control signal generating unit. The developing roller carries toner. The magnetic roller performs supply of toner to the developing roller and removal of toner from the developing roller. The transformer includes a primary side to which a capacitor is connected and a secondary side from which an AC voltage is output and applied to the developing roller. The control signal generating unit inputs a control signal to the capacitor and adjusts a DC bias value of the control signal so that a DC component of the control signal is the same before and after the change of the duty ratio of the control signal.
    Type: Grant
    Filed: March 28, 2013
    Date of Patent: May 19, 2015
    Assignee: KYOCERA Document Solutions Inc.
    Inventor: Kensuke Fujihara
  • Patent number: 9025979
    Abstract: An image forming apparatus includes an image carrier and the following elements. A charging unit charges the image carrier. An exposure unit exposes the charged image carrier to light and forms an electrostatic latent image. A developing unit generates a developing electric field and develops the electrostatic latent image. A transfer unit transfers the developed image. A controller outputs an AC setting signal. The developing unit includes a bias power supply source having the following elements. An output transformer includes a primary winding and a secondary winding. A switching circuit supplies a current to the primary winding. A current control circuit includes first impedance and second impedance. The first impedance is set when the AC voltage has a first frequency and the second impedance is set when the AC voltage has a second frequency, thereby controlling a current flowing between the primary winding and the switching circuit.
    Type: Grant
    Filed: January 23, 2013
    Date of Patent: May 5, 2015
    Assignee: Fuji Xerox Co., Ltd.
    Inventor: Yuya Sakurabayashi
  • Publication number: 20150104207
    Abstract: An image forming apparatus includes a charging member, a charging bias power source, a developing member, a developing bias power source and a controlling device. The charging member electrically charged an image carrier. The charging bias power source applies a DC charging bias to the charging member. The developing member develops a toner image onto the image carrier. The developing bias power source applies an AC and DC developing bias to the developing member. The controlling device carries out, before image forming process, pre-charging control controlling the charging bias power source to electrically charge the image carrier. The controlling device carries out, after the image forming process is started, post-charging control controlling the charging bias power source and developing bias power source to adjust an electrical potential difference between a surface potential of the image carrier and developing bias to a significant electrical potential difference preventing occurrence of image failure.
    Type: Application
    Filed: September 9, 2014
    Publication date: April 16, 2015
    Applicant: KYOCERA Document Solutions Inc.
    Inventor: Shingo SAKATO
  • Publication number: 20150104208
    Abstract: An image forming apparatus includes an image carrier, a developing device, a bias applying unit, a leak detecting unit, a bias controller and a leak detection controller. The developing device includes a magnetic roller and a developer layer. The bias applying unit applies development biases to the magnetic roller and the developing roller. The leak detecting unit detects a leak generated between the image carrier and the developing roller or a leak generated between the developing roller and the magnetic roller. The leak detection controller performs a leak detecting operation for detecting the value of an inter-peak voltage of the alternating current voltage of the development bias applied to the developing roller, at which the leak is generated, while changing the inter-peak voltage at a time different from that during the developing operation.
    Type: Application
    Filed: October 6, 2014
    Publication date: April 16, 2015
    Inventors: Tamotsu Shimizu, Yukihiro Mori
  • Publication number: 20150098717
    Abstract: An electrophotographic image forming apparatus including a photoreceptor on which an electrostatic latent image is formed, a developing roller for forming a visual toner image by supplying toner onto the electrostatic latent image, a transfer unit for transferring the visual toner image onto a recording medium, and a cleaning member for removing residual toner remaining on the photoreceptor after the transfer of the visual toner image from the photoreceptor is described. The image forming apparatus operates in a printing mode, and a collecting mode in which the residual toner on the cleaning member is collected on the developing roller via the photoreceptor. A linear velocity of the developing roller in the collecting mode is faster than in the printing mode.
    Type: Application
    Filed: April 3, 2014
    Publication date: April 9, 2015
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Sung-min PARK, Dong-uk Kim, Ki-hyun Yoo
  • Patent number: 9002226
    Abstract: A developing device which includes a developing roller which supplies a toner to a photoreceptor and a supply roller which performs supply of a toner to the developing roller and peeling of a toner from the developing roller, and applies a bias voltage to the developing roller so as to develop an electrostatic latent image formed on the photoreceptor with a toner. The developing device includes a first current measuring portion which measures a value of a current flowing in the developing roller, a second current measuring portion which measures a value of a current flowing in the supply roller, and a control portion which calculates a toner charging amount on the developing roller and a toner peeled amount by the supply roller based on measured results by the first current measuring portion and the second current measuring portion.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: April 7, 2015
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Toshimasa Hamada
  • Publication number: 20150093130
    Abstract: An image forming apparatus includes an apparatus main body, a power supply switch, a photoreceptor drum, a charging device, an exposure device, a developing device, a transfer roller, a cleaning device, and a toner-layer formation unit. The transfer roller contacts the circumferential surface of the photoreceptor drum at a downstream side with respect to the developing device in the rotation direction and is configured to transfer the toner image to a sheet. The cleaning device is cleaning device arranged opposed to the photoreceptor drum, downstream. The cleaning device is configured to clean the photoreceptor drum. The toner-layer formation unit is configured to form a toner layer on a surface of the transfer roller in an initial operation started after the apparatus main body is installed in a predetermined installation location and the power supply switch is switched on.
    Type: Application
    Filed: September 27, 2014
    Publication date: April 2, 2015
    Inventor: Einosuke Kikuchi
  • Patent number: 8989639
    Abstract: An image forming apparatus includes a toner carrying roller for carrying a toner, an image carrying member, contacting the toner on the toner carrying roller, on which a toner image is to be formed with the toner, and an electrode portion provided at an opposing position in which the electrode portion opposes the toner carrying roller via the image carrying member interposed therebetween. The toner image is formed on the image carrying member by changing a value of a voltage, on the basis of image information, applied to the electrode portion, and the toner carried on the toner carrying roller and the image carrying member contact each other in a toner contact area. The toner is moved between the toner carrying roller and the image carrying member in a toner movement area by changing the value of the voltage applied to the electrode portion, and the toner movement area is present downstream of the toner contact area with respect to a movement direction of the image carrying member.
    Type: Grant
    Filed: November 18, 2011
    Date of Patent: March 24, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasunari Kobaru, Yasuo Yoda, Takahiro Uchiyama, Yoshiki Kudo, Takeshi Kawamura, Tatsuaki Orihara, Naoto Tsuchihashi, Hidetoshi Hanamoto
  • Publication number: 20150078773
    Abstract: When a toner charging amount for toner in a liquid developer conveyed to a development portion is set, a wet-type image formation apparatus performs a sensing operation in which a sensing unit senses image densities of a plurality of patch images formed at different development biases with the toner charging amount being set to a constant value, and a setting operation in which, in a case where a control unit calculates current development characteristics based on the image densities of the plurality of patch images sensed by the sensing unit, and determines that the current development characteristics are not included within a set target range, the control unit controls a charging unit to set the toner charging amount such that the development characteristics are included within the set target range.
    Type: Application
    Filed: September 11, 2014
    Publication date: March 19, 2015
    Applicant: Konica Minolta, Inc.
    Inventors: Takeshi MAEYAMA, Atsuto HIRAI, Yuuya SATO, Makiko WATANABE
  • Patent number: 8983320
    Abstract: An image forming apparatus includes a latent-image bearing body, a charging unit, a latent-image writing unit, a development unit, a development power, and a bias control unit. After a start of an image forming operation, the bias control unit performs a process of constantly maintaining an output of a development bias at an adjustment bias value. The adjustment bias value is a central value in a periodic fluctuation range of the output of the development bias. At a timing at which a difference of the development bias from the adjustment bias value in the periodic fluctuation range is less than or equal to a predetermined threshold value, the bias control unit performs switching from the process of constantly maintaining the output of the development bias at the adjustment bias value to a process of periodically changing the output of the development bias based on development bias control data.
    Type: Grant
    Filed: March 11, 2014
    Date of Patent: March 17, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Shingo Suzuki, Satoshi Kaneko, Tetsuya Muto, Shuji Hirai, Shinichi Akatsu, Keita Gotoh, Yuuichiroh Uematsu
  • Publication number: 20150071663
    Abstract: An image forming device includes a charging power supply used in applying, to a charging unit, a charging voltage for the purpose of electrostatic latent image formation and a charging bias voltage during a cleaning operation; a developing power supply that is capable of outputting a developing bias voltage of positive polarity and negative polarity to a developing unit; a constant-voltage generating-holding unit that is used in generating and holding a constant potential difference between the charging unit and the developing unit; a developing power control unit that performs output control of a developing bias voltage with respect to the developing unit; and a charging power control unit that, when the developing power control unit performs control to output a developing bias voltage of reverse polarity to the charging unit, performs output control of the charging bias voltage of a predetermined level with respect to the charging power supply.
    Type: Application
    Filed: September 4, 2014
    Publication date: March 12, 2015
    Inventor: Yu YOSHIOKA
  • Patent number: 8977150
    Abstract: An image forming apparatus includes a rotatable photoconductor, a charging unit, an exposure unit to expose the photoconductor to reduce an electrical potential at the photoconductor, a developing unit to charge the toner held on a toner bearing member with friction and attract the toner to the exposed portion on the photoconductor by supplying a development voltage from a first power source and using an electrical potential difference between the toner bearing member and the photoconductor in the development area, a reverse development voltage controller to supply a reverse development voltage while a non-charged portion on the photoconductor passes the development area, and a developer reducing potential applier to supply a development restraining potential and an absolute value smaller than a target charging potential to the photoconductor while the reverse development voltage is supplied.
    Type: Grant
    Filed: November 15, 2012
    Date of Patent: March 10, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Shin Yamamoto, Shin Murayama, Yoshio Sakagawa, Yuji Nagatomo
  • Patent number: 8977151
    Abstract: An image forming apparatus having; a latent image support member; a latent image forming unit for forming an electrostatic latent image on the latent image support member; a developer support member for supplying toner to the latent image support member to develop the electrostatic latent image; a voltage applying device for applying a developing bias, which is a superimposed voltage of a DC voltage and an AC voltage, to the developer support member; a first selecting device for selecting a screen ruling; and a second selecting device for selecting a frequency of the AC voltage. The second selecting device selects a first frequency when the first selecting device selects a first screen ruling, and selects a second frequency lower than the first frequency when the first selecting device selects a second screen ruling higher than the first screen ruling.
    Type: Grant
    Filed: August 1, 2012
    Date of Patent: March 10, 2015
    Assignee: Konica Minolta Business Technologies, Inc.
    Inventor: Kunio Furukawa
  • Publication number: 20150063849
    Abstract: In an image forming apparatus, a high-density portion and a low-density portion are arranged close to each other such that a boundary between the high-density portion and the low-density portion intersects with the conveyance direction of a density detection patch. A controller compares, in the conveyance direction, temporal change in the density detection value at a boundary portion shifting from the high-density portion to the low-density portion, with temporal change in the density detection value at a boundary portion shifting from the low-density portion to the high-density portion, and sets a process condition based on a result of the comparison.
    Type: Application
    Filed: August 19, 2014
    Publication date: March 5, 2015
    Inventors: Hideki Ishida, Hiroki Tanaka