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Bias control

Subclass of:

399 - Electrophotography

399038000 - CONTROL OF ELECTROPHOTOGRAPHY PROCESS

399053000 - Control of developing

Patent class list (only not empty are listed)

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Class / Patent application numberDescriptionNumber of patent applications / Date published
399056000 In response to potential of latent image 6
Entries
DocumentTitleDate
20130028621IMAGE FORMING APPARATUS - An image forming apparatus having; an electrostatic latent image support member; an electrostatic latent image forming section; a developer support member; a first voltage applying device for applying a developing bias voltage that is a superimposed voltage of a first DC voltage and a first AC voltage to the developer support member; and a controller for controlling the first voltage applying device. The first voltage applying device is controlled to stop an output of the first AC voltage at a first frequency, to change the first DC voltage outputted therefrom from a first voltage value to a second voltage value and to start an output of the first AC voltage at a second frequency, in this order. The controller selects a screen ruling for each page in accordance with image data and determines the output from the first voltage applying device in accordance with the selected screen ruling.01-31-2013
20090196639Image forming apparatus, developing device, and method of adjusting developer - An image forming apparatus includes an image supporting member; a developer supporting member for attaching developer to the image supporting member to form a developer image; a regulation member for forming a thin layer of the developer on the developer supporting member; a charge adjustment member for receiving a charge adjustment voltage and contacting with the thin layer of the developer formed on the developer supporting member to adjust a charge amount of the developer; and a charge adjustment voltage switching unit for switching the charge adjustment voltage applied to the charge adjustment member between an image forming voltage upon forming an image and a non-image forming voltage during a preparation operation.08-06-2009
20130034360IMAGE FORMING APPARATUS - 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.02-07-2013
20100092197IMAGE FORMING APPARATUS - An image forming apparatus performs a control sequence in which an AC voltage having a peak-to-peak voltage is applied to a charging member so that a relationship between an absolute value of a surface potential of an image bearing member at a portion under a transfer residual toner remaining on the image bearing member which has been electrically charged by the charging member during non-image formation and an absolute value of a surface potential of a developer carrying member is reversed with respect to a relationship between these absolute values during image formation.04-15-2010
20100092196DEVELOPING CARTRIDGE AND IMAGE FORMING APPARATUS USING THE SAME - A developing cartridge includes: a developing roller for developing an electrostatic latent image of a photoconductor with a toner; and a developing tank for storing the toner to be supplied to the developing roller, the developing tank including: a toner receiving port for receiving the toner to be stored; a shutter having a function for sliding to open and close the toner receiving port, the shutter being adapted to be maintained in a closed state by an electrically-releasing adhesive; and a pair of conductive member for supplying an electric current to the electrically-releasing adhesive to open the shutter.04-15-2010
20090041492IMAGE FORMING APPARATUS - An image forming apparatus, which reduces toner spatter and produces a good quality image when forming a toner image using the direct recording method. An image forming part includes: a toner carrier for carrying toner; and toner controlling means, which is disposed between the toner carrier and recording paper on which the toner is made to adhere, and which has a plurality of toner passage holes, the toner controlling means having a control electrode for controlling the passage of toner on the toner carrier side surface in the area around the toner passage hole, and forming a toner image by causing the toner to fly to the recording paper, and the image forming apparatus having liquid applying/humidifying means for either applying a liquid to or humidifying the imaging surface of the recording paper prior to forming a toner image.02-12-2009
20090041491PROCESS CARTRIDGE AND IMAGE FORMING APPARATUS USING THE SAME - An image forming apparatus includes an image carrying member, an image writing unit, a development unit, a transfer device, a charging device, and a toner charge control device. The image writing unit forms a latent image on the image carrying member, which is developed as a toner image by the development unit, and the toner image is transferred to a transfer member by the transfer device. The charging device charges the image carrying member and toner on the image carrying member. The toner charge control device, controls a polarity of charge and charging voltage level of toner remaining on the image carrying member. The toner charge control device includes an endless belt having a surface made of a conductive material, a support member extending the endless belt pressed against the image carrying member, and a bias voltage applicator for supplying a voltage to the surface of the endless belt.02-12-2009
20090232533Image Forming Apparatus and Image Forming Method - An image forming apparatus according to the present invention includes an image carrier, a charging section that electrically charges the image carrier, an exposure section that exposes the image carrier to light to form a latent image, a development section that develops the latent image by means of a liquid developer containing carrier and toner particles, a first squeezing roller that is held in contact with the image carrier carrying an image developed by the development section and adapted to bear a bias voltage Vs09-17-2009
20090010666DEVELOPMENT APPARATUS, IMAGE FORMING APPARATUS AND DEVELOPMENT METHOD - The development apparatus that develops an electrostatic latent image formed on an image carrier comprises: a developer roller operable to carry toner on a circumferential surface thereof and develop the electrostatic latent image using the toner; a supply roller operable to perform toner supply to the developer roller; a voltage applier operable to apply a bias voltage V01-08-2009
20120114350IMAGE FORMING APPARATUS - An image forming apparatus includes a first rotating unit, an image carrier, an electrostatic latent image forming unit, a third rotating unit, an intermediate transfer body, first and second transfer units, and the following elements. A developing device includes a rotating body, a second rotating unit, plural developing units. A supply unit supplies a bias to a developer carrying member of each developing unit. A setting unit sets the bias to a first condition to develop the latent image of a first color at least while the latent image is being located at the developing position, and sets the bias to a second condition to suppress transferring of the toner in the subsequent developing unit to the image carrier after the second rotating unit starts rotating the rotating body from a waiting position and before stopping rotating the rotating body and locates the subsequent developing unit at the developing position.05-10-2012
20120237236IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD - Image forming apparatus to expose-scan electrically charged surface of image carrier based on image data in unit of page to form electrostatic latent image, and develop electrostatic latent image at development position on image carrier by using developer carried by developer carrier. The image forming apparatus determines, based on image data of page, first and second partial regions having first and second attributes in page, not overlapping in sub scanning direction, and switches development bias voltage value and/or rotational speed of developer carrier to value for first attribute while electrostatic latent image on image carrier corresponding to first partial region passes through development position, and to value for second attribute while electrostatic latent image corresponding to second partial region passes through development position.09-20-2012
20100226675Image Forming Apparatus - An image forming apparatus is provided. The image forming apparatus includes an accommodating member configured to accommodate developer; a supply member configured to supply the developer of the accommodating member; a developer holding member configured to supply the developer from the supply member to an image holding member; and a voltage controller configured to apply a first predetermined voltage to the supply member and apply a second predetermined voltage to the developer holding member so as to supply the developer from the accommodating member to the electrostatic latent image formed on the image holding member through the supply member and the developer holding member. The voltage controller, when starting to apply a voltage to the supply member, applies an excessive voltage to the supply member, the excessive voltage having a polarity same as the first predetermined voltage and being larger in an absolute value than the first predetermined voltage.09-09-2010
20090169229Image Forming Apparatus, Image Forming Method, Image Forming Computer Program, and Computer Readable Storage Medium Containing The Program - The image forming apparatus include: a resistance detection section (07-02-2009
20090310995IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD - In case new and old toners may be mixed, a developing bias is set as follows. The time is first clocked. The number of times toner is replenished from a hopper into a buffer for a clocked period is counted. If a replenishment amount per clock time is a threshold value or higher, considering that new and old toners are mixed, the setting of the developing bias is changed. An electric field intensity between a developing roller and a photoconductor is set to cause normally-charged toner to fly in an image area but not to fly in a background area. No image fogging is therefore generated in the background area. Thus, an image forming apparatus and method capable of preventing low-charged toner and oppositely-charged toner generated by mixing of new and old toners from adhering to the background area of an electrostatic latent image on the photoconductor, thereby avoiding generation of image fogging.12-17-2009
20090087205IMAGE FORMING APPARATUS - A development device configured to develop an electrostatic image formed on an image bearing member by applying a developing bias in a development operation includes a developer bearing member configured to bear a developer, a bias applying unit configured to apply an input waveform bias including an alternating component to the developer bearing member, a bias detection unit configured to detect information concerning an output waveform bias generated on the developer bearing member when the bias applying unit applies the input waveform bias to the developer bearing member, and a controller configured to execute a mode for controlling the developing bias to be applied to the developer bearing member based on the input waveform bias and the output waveform bias.04-02-2009
20090162085Device for measuring electrostatic charge amount of toner and method for measuring distribution of electrostatic charge amount of toner - A device for measuring electrostatic charge amount of toner is provided. The device comprises a hollow toner suction port for sucking the toner from a toner substrate and a means for measuring electrostatic charge amount of the sucked toner. The toner suction port forms a hermetically sealed space with the toner substrate.06-25-2009
20090279911METHOD FOR CALIBRATING BID CURRENT IN ELECTRO-PHOTOGRAPHIC PRINTER - A method for calibrating the BID current in an electrophotographic printer includes the steps of measuring electrode capacitance of an empty BID unit, installing the BID unit in an electrophotographic printer, comparing the measured capacitance with a calibration curve to determine the proper current for the BID unit, and adjusting the operating current of the BID unit according to the calibration curve.11-12-2009
20090297192Developing device, image forming apparatus and method of forming image - An image forming apparatus includes an image supporting member for supporting a static latent image; and a developer supporting member for developing the static latent image formed on the image supporting member using developer. It is configured to supply developer to the developer supporting member so that a ratio of a maximum amount of the developer on the image supporting member per unit area with respect to an amount of the developer on the developer supporting member per unit area does not exceed 0.60.12-03-2009
20100111552Image Forming Apparatus with Developing Roller Cleaning Capability - An image forming apparatus includes a photosensitive member, a developing roller, a toner supply roller, and a charging member. The toner supply roller supplies single-component non-magnetic toner to the developing roller for developing a latent image formed on the photosensitive drum. In a toner cleaning mode, the toner supply roller removes the toner from the developing roller. To this effect, the charging member charges up the toner held on the developing roller. A bias circuit and a controller are further provided, wherein the bias circuit applies bias voltages to the developing roller, supply roller, and charging member, and the controller controls the bias circuit to produce the bias voltages such that a potential difference between the charging member and the supply roller is greater than a potential difference between the developing roller and the supply roller in the toner cleaning mode.05-06-2010
20100061749IMAGE FORMING APPARATUS AND IMAGE FORMING SYSTEM - An image forming apparatus includes a developer bearing member configured to bear a developer to develop a latent image, a developer regulating member configured to regulate an amount of the developer carried on the bearing member, a voltage application unit that can apply a plurality of direct current voltages of different values between the bearing member and the regulating member, and a current detection unit that can detect a plurality of direct currents of different values flowing in the regulating member when the voltage application unit applies the plurality of direct current voltages, wherein the image forming apparatus sets a direct current voltage value Vb applied by the voltage application unit when developing the latent image, so that the following expression is satisfied: |Vb|>|Vbmin|, where Vbmin indicates a direct current voltage value when the direct current detected by the current detection unit is a minimum value.03-11-2010
20100061750IMAGE FORMING APPARATUS - An image forming apparatus includes a image bearing member (drum); a developing device for forming a developing portion at which an electrostatic latent image formed on the drum is developed with toner; a toner supply device for supplying toner to the developing device; a density detecting portion for detecting a density of a control toner image formed on the drum; a toner ratio detecting portion for detecting a toner ratio in a two component developer contained in the developing device; a transfer member for forming a transfer portion; a charging member for electrically charging the toner image formed by the developing device by being supplied with a bias of an identical polarity to a charge polarity of the toner; an adjusting portion for adjusting an amount of the toner supplied from the toner supply device so that the toner ratio is below a preset lower limit when the toner ratio detected by the toner ratio detecting portion reaches the lower limit; and a bias determining portion for determining, after the adjustment by the adjusting device, a condition of a bias to be applied to the charging member on the basis of a detection result of the density detecting portion with respect to the density of the control toner image formed on the drum.03-11-2010
20080240759Developing device, image forming device, and image forming method - A developer device applies bias voltage including an alternating-current component equal to or larger than a value corresponding to a developing electric field of 9 V/μm to a developing roller. The bias voltage is set to apply developer to a latent image on a photosensitive element to develop the image in an image forming mode. The bias voltage is set so that a difference between an area central potential and a surface potential of the photosensitive element is shifted to a direction attracting the normally charged developer to a developer carrier, in relation to a difference between an area central potential and a surface potential of the image carrier in the latent image section in the image forming mode, and a supply amount of the developer to the photosensitive element is smaller than that in the latent image section in the image forming mode.10-02-2008
20100129102IMAGE FORMING APPARATUS AND METHOD FOR CONTROLLING SAME - An image forming apparatus includes: a photoconductive drum; a developing roller carrying toner; a DC voltage application portion outputting a DC voltage to be applied to the developing roller, and receiving a feedback voltage; an AC voltage application portion applying an AC voltage to be applied to the developing roller; a detection portion detecting occurrence of electric discharge; a first resistor portion generating a feedback voltage that is fed to the DC voltage application portion; a second resistor portion connected between the DC voltage application portion and the AC voltage application portion, and having a switching portion with which conducting on and off are switchable; and a control portion controlling the switching portion, at the time of printing, to bring the second resistor portion into a conducting state and, at the time of electric discharge detection, to bring the second resistor portion into a non-conducting state.05-27-2010
20100135685IMAGE FORMING APPARATUS AND CONTROL METHOD THEREOF - An image forming apparatus and a control method thereof are disclosed. A charge unit charges a surface of an organic photo conductor (OPC) to a predetermined electric potential. A developing unit develops an electrostatic latent image formed on the surface of the OPC by coating a developer on the same. A power supply unit supplies power to the charge unit and the developing unit. A control unit regulates the power supplied to the charge unit and the developing unit. After a developing process in the developing unit, the control unit regulates the power applied to at least one of the charge unit and the developing unit so as to collect a residual developer on the surface of the OPC to the developing unit. Accordingly, contamination of the charge unit and the transfer unit can be prevented and an image of a good quality can be achieved.06-03-2010
20090162086IMAGE FORMING APPARATUS - There is provided an image forming apparatus, including: a image bearing member; a charging member; a developing device; a transfer member that forms a transfer portion, thereby transferring a toner image on the image bearing member, to a transfer material; a first toner charging member disposed on the lower stream side of the transfer portion and on the upper stream side of the charging member in a rotating direction of the image bearing member, thereby charging the toner on the image bearing member by applying voltage; wherein the developing device develops the electrostatic latent image and recovers the toner charged by the first toner charging member, the image forming apparatus further including: a first current detecting portion that detects a current value flowing through the first toner charging member; and a changing portion that changes a transfer condition according to the detected current value.06-25-2009
20120070170DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - 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.03-22-2012
20090052918IMAGE FORMING APPARATUS AND METHOD OF DETECTING AMOUNT OF RESIDUAL DEVELOPER - An image forming apparatus having a developer container containing a developer and a developer carrying member for carrying the developer and adapted to switch an AC voltage to be applied to the developer carrying member, the apparatus comprising a detecting member for detecting the amount of developer in the developer container and a processing portion for determining the amount of developer in the developer container according to the value output by the detecting member when the AC voltage is applied to the developer carrying member, the processing portion being adapted to determine the amount of developer by executing a process that corresponds to the operation of switching the AC voltage.02-26-2009
20110142466REDUCING RELOAD IMAGE QUALITY DEFECTS - An image forming apparatus includes a sensor that is configured to detect a property of a developer material, a transport unit that is operatively in contact with the developer material and that is configured to move the developer material toward a recording medium, and a controller that receives the property of the developer material from the sensor unit and sets a voltage of the transport unit, wherein the voltage is determined based on the property of the developer material received from the sensor.06-16-2011
20090052917Image forming apparatus - A disclosed image forming apparatus comprises: a conveying belt conveying a record medium attracted to the conveying belt using electrostatic force; a recording head for ejecting droplets on the record medium and forming an image; and a voltage waveform applying unit applying voltage waveforms, in which the shape of a positive waveform and the shape of a negative waveform are different, to the conveying belt so as to apply positive and negative electric charge thereto and generate the electrostatic force.02-26-2009
20090080921Image forming apparatus - An image forming apparatus includes a latent image bearing body that bears a latent image, a charging member applied with a charging voltage and configured to charge a surface of the latent image bearing body, a developer bearing body applied with a developing voltage and configured to develop the latent image with a developer, a developer regulating member applied with a regulating-member-application voltage and configured to form a layer of the developer on the developer bearing body, and a voltage switching unit configured to switch the regulating-member-application voltage. In a non-image-forming period, the voltage switching unit switches the regulating-member-application voltage from a voltage set for an image forming period to a different voltage.03-26-2009
20110229175DEVELOPING APPARATUS - A developing apparatus including a developing container for containing developer, the developing container having an opening portion, a developer carrying member for carrying the developer at the opening portion, a detecting member for detecting a developer amount, the detecting member detecting a capacitance between the developer carrying member and the detecting member, and a force receiving portion for receiving a force and moving the developing container between a first position in which a developing operation is performed by the developer carrying member and a second position in which the developing operation is not performed, wherein the capacitance can be detected in the second position, and the detecting member is a rotatable developer supplying member for supplying the developer to the developer carrying member, the developer supplying member including a foam layer in which the developer can enter.09-22-2011
20090220265DEVELOPING BIAS CONTROL DEVICE CAPABLE OF PROPERLY CONTROLLING DEVELOPING BIAS VOLTAGE - Upon receiving a request to control developing bias voltage, first and second square-wave signal output units output first and second square-wave signals, respectively. When a rising edge of the first square-wave signal coincides with a rising edge of the second square-wave signal, the rising edge of the second square-wave signal is advanced with respect to the rising edge of the first square-wave signal. When a falling edge of the first square-wave signal coincides with a falling edge of the second square-wave signal, the falling edge of the second square-wave signal is delayed with respect to the falling edge of the first square-wave signal. Subsequently, a voltage-controlling square-wave signal for controlling developing bias voltage is generated based on the first and second square-wave signals.09-03-2009
20090252515IMAGE FORMING APPARATUS - An image forming apparatus includes an alternating-current high-voltage power supply generating an alternating-current bias for detection of the remaining amount of toner. The alternating-current high-voltage power supply includes a piezoelectric transformer, a piezoelectric-transformer driving unit, a piezoelectric-transformer driving-signal generating unit, a voltage detecting unit, a voltage setting unit, and an controlling unit that feeds back a difference signal between a detection level signal supplied from a detection signal detecting unit and a setting signal supplied from the voltage setting unit to the piezoelectric-transformer driving-signal generating unit to control an output voltage from the piezoelectric-transformer.10-08-2009
20090252513Developing device and image forming apparatus - A developing device and image forming apparatus are provided, wherein high quality images, in which generation of development hysteresis (ghost image) is alleviated, are obtained over a long period using a hybrid development method comprising a toner-supplying developer supporting member and a toner-collecting developer supporting member. Bias voltage is applied in the direction in which the toner is supplied to the toner supporting member in the toner supply region and the toner collection region of the toner-supplying developer supporting member and the toner-collecting developer supporting member respectively so that the toner collecting capability in the toner collection region is higher than the toner collecting capability in the toner supply region.10-08-2009
20090252514DEVELOPING APPARATUS - A developing apparatus includes a developer carrying member rotatably provided for carrying a developer; a regulating member that has conductivity, and is provided to be capable of being in contact with the developer carrying member for regulating a amount of the developer carried by the developer carrying member; a power supply that applies voltage to the regulating member; a deformation detecting unit that detects information relating to the deformation of the developer carrying member; and a control unit that controls the power supply to apply a correction voltage when a deformed portion of the developer carrying member passes through the regulating member in order that the amount of the developer carried by the developer carrying member in the circumferential direction is in uniform based on a result of the detection by the deformation detecting unit.10-08-2009
20120195615PRINTER WITH DISCHARGE AREA DEVELOPED TONER BALANCING - Printers are provided. In one aspect, at least one first toner image is formed and transferred onto a receiver to form a composite toner image on a receiver having a first polarity. A second development station of a toner layer balancing system creates a second development difference of potential of the first polarity between a bias member and the first toner at each location of the receiver, to cause a second toner of the first polarity to deposit at individual locations on the receiver in amounts according to the second net development difference of potential at the individual locations such that total amount of first toner and any second toner deposited at each location on the receiver is within a range that is less than a range of first toner amounts on the receiver.08-02-2012
20120195614ENHANCEMENT OF CHARGE AREA DEVELOPED TONER - Methods for printing are provided. In one aspect a primary imaging member having a pattern of engine pixel locations with image modulated differences of potential of a first polarity and with first toner having a first toner difference of potential of a second polarity is moved to a second development station. A second development difference of potential of the first polarity at the second development station forms a second net development difference of the second development difference of potential less any image modulated difference of potential at the individual engine pixel location and less any difference of potential relative to ground of any first toner at the individual engine pixel location. The second development difference of potential is less than the first development difference of potential so that second toner that is different from the first toner, is developed onto the first toner using the second net development difference of potential.08-02-2012
20120195613PRINTER WITH CHARGE AREA DEVELOPED TONER BALANCING - Printers are provided. In one aspect, at least one first toner image is formed and transferred onto a receiver to form a composite toner image on a receiver having a second polarity. A second development station of a toner layer balancing system creates a second development difference of potential of a first polarity between a bias member and the first toner at each location of the receiver, to cause a second toner of the second polarity to deposit at individual locations on the receiver in amounts according to the second net development difference of potential at the individual locations such that total amount of first toner and any second toner deposited at each location on the receiver is within a range that is less than a range of first toner amounts on the receiver.08-02-2012
20100226674IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD - An image forming apparatus includes a developing section that includes a feed member having a groove, a developer carrier developing with liquid developer fed from the feed member, and a charging member charging the liquid developer carried in the developer carrier. An image carrier carries an image developed by the developing section. An optical sensor includes a light emitting section emitting light to the image developed in the image carrier. A first light receiving section receives light reflected from the image. A second light receiving section is disposed at a position different from that of the first light receiving section. A control section adjusts a developing bias applied to the developer carrier in response to an output signal of the first light receiving section, and controls a bias applied to the charging member by the output signals of the first and second light receiving sections.09-09-2010
20110058836DEVELOPING DEVICE, AND CONTROLLING METHOD THEREOF - A developing device is provided with a developer transporting member for transporting a developer containing a toner and a carrier; a toner transporting member opposite to the developer transporting member and opposite to an electrostatic latent image carrying member; a first electric field forming device, which is composed of a power source for the developer transporting member and a power source for the toner transporting member, for shifting the toner in the developer held onto the developer transporting member to the toner transporting member; and a second electric field forming device for shifting the toner held onto the toner transporting member to an electrostatic latent image on the carrying member. Operation of the first electric field forming device is controlled based on an electric current flowing in the developer transporting member power source, which is detected by a detecting block.03-10-2011
20110058835DEVELOPING DEVICE, AND CONTROLLING METHOD THEREOF - A developing device is provided with a first transporting member for transporting a developer containing a toner and a carrier; a second transporting member opposite to the first transporting member to interpose a first spatial region therebetween and opposite to an electrostatic latent image carrying member to interpose a second spatial region therebetween; a first electric field forming device, composed of first and second power sources, for shifting the toner in the developer held onto the first transporting member to the second transporting member; and a second electric field forming device, composed of the second power source, for shifting the toner held onto the second transporting member to an electrostatic latent image on the carrying member. The operation of the second electric field forming device is controlled based on electric currents flowing in the first and second power sources, which are detected by first and second detecting blocks, respectively.03-10-2011
20100239291HIGH-VOLTAGE POWER SUPPLY - A high-voltage power supply for applying a developing bias to a developing roller of an image forming apparatus is provided. The high-voltage power supply includes: a developing bias application unit that applies a developing bias to the developing roller in accordance with a control voltage that is input therein; a developing bias detection unit that detects the developing bias applied to the developing roller; a control voltage adjustment unit that adjusts the control voltage input to the developing bias application unit such that the developing bias detected by the developing bias detection unit approaches a predetermined target value; and a condensation determination unit that determines condensation of the developing bias application unit based on the control voltage.09-23-2010
20100254725DEVELOPMENT APPARATUS AND IMAGE FORMING APPARATUS - Provided are a development apparatus and an image forming apparatus which, in a hybrid development apparatus provided with a plurality of toner carriers, a toner supply capability to supply toner to each toner carrier is controlled independent of development electric fields between the toner carriers and an image carrier, whereby each toner carrier is allowed to exhibit a desired development capability, and even in the case of high speed development, a high quality image is provided. The phases, the frequencies, and/or the duty ratios of the alternating current components of the voltages applied to the plurality of the toner carriers are made to be different, whereby the toner supply amount for each toner carrier from the developer carrier is controlled independently of the development electric fields between the toner carriers and the image carrier.10-07-2010
20120195616Image Forming Apparatus - An image forming apparatus includes first photosensitive members, first chargers for charging the first photosensitive members, developer carriers for supplying developer to the first photosensitive members, a first charging-bias applying unit that applies charging biases to the first chargers, development-bias applying units for applying development biases to the corresponding developer carriers, a charging-current sensing unit that separately senses a charging current flowing in each of the first chargers, and a control unit that controls the development biases based on the sensed charging current. When a difference between a reference charging-current value and a detected charging-current value exceeds a predetermined value, if the detected charging-current value is larger than the reference charging-current value, the control unit increases an absolute value of a development bias applied to a developer carrier corresponding to the charger having the difference exceeding the predetermined08-02-2012
20090110422IMAGE FORMING APPARATUS AND CONTROL METHOD THEREOF - An image forming apparatus includes a density detector to detect a density of an image to be printed, and an image density controller to adjust a toner supply amount and a developing bias based on a detection result of the density detector to thereby adjust a density of the image.04-30-2009
20090214240DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - A developing device capable of improving the image density and the dot reproducibility, and an image forming apparatus including the same are provided. A developing device applies an alternating voltage superimposed on a direct current voltage to a developing roller to thereby develop an electrostatic latent image formed on a photoreceptor with toner. A bias voltage waveform superimposed at this time has an original period (first period) in which each of a development-side electrical potential and an opposite development-side electrical potential is applied one time and a period (second period) in which a Vpp is gradually increased from the initial value to the maximum value.08-27-2009
20110243592ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS USING A PERIODIC WAVE AS A DEVELOPING BIAS - An image forming apparatus comprises an image carrier, a developing unit, a supply unit and a control unit. A developing unit visualizes an electrostatic latent image formed on a surface of the image carrier, using a developing material. A supply unit supplies a periodic wave as a developing bias to the developing unit. A single period of the periodic wave is formed by a first time period and a second time period. In the first time period a voltage in which a DC voltage and an AC voltage are superimposed is applied. In the second time period only a DC voltage is applied. A control unit changes the duration of the second time period according to the amount of electrostatic latent images that have been formed in succession.10-06-2011
20110085811Image Forming Device - An image-forming device can include an image acquiring unit that acquires image data, an image forming unit that forms an image based on the image data, a determining unit that determines whether the image data includes a part having density greater than or equal to a prescribed density, and a controller. The image forming unit can include a developing roller, a supply roller for supplying developer to the developing roller, and a bias applying unit that applies first and second voltages between the developing roller and the supply roller in first and second modes, respectively. The controller can control the bias applying unit to apply one of the first and second voltages when the determining unit determines whether the image data includes the part having density greater than or equal to a prescribed density.04-14-2011
20100061751IMAGE FORMING APPARATUS - The present invention provides an image forming apparatus, which is able to prevent the adherence of toner on the surface of toner controlling means and around a toner passage hole, and to stably carry out toner passage ON/OFF control when forming an image using the direct recording method. This image forming apparatus includes: a toner carrier; recording medium means; toner controlling means, disposed between the toner carrier and recording medium means, and having a plurality of toner passage holes; and cloud electrode means disposed between the toner carrier and toner controlling means, a toner cloud being formed by applying an AC bias between the toner carrier and cloud electrode means. A control electrode and a common electrode are disposed in toner controlling means, and when the toner of the toner carrier is able to pass through the toner controlling means toward recording medium means, a loop-shaped line of electric force is formed between the recording medium means side and the toner controlling means common electrode, the loop-shaped line by-passing the control electrode.03-11-2010
20110097097Image forming apparatus with developing units having different voltage levels - An image forming apparatus is disclosed. Zener diode separately installed to correspond to each developing device so as to form a difference in potential between the developing bias voltage and the supply bias voltage of each developing device, is installed at a common end, so that a deviation of the developing voltage applied to the developing device affected by a deviation of Zener diode components can be reduced, resulting in an increased color image quality. In addition, the Zener diode is installed in a common end, such that the number of Zener diodes is reduced, resulting in a reduction in production costs.04-28-2011
20100054780IMAGE FORMING APPARATUS - An image forming apparatus includes an image bearing member for bearing an electrostatic latent image; a developing device including a developer carrying member for carrying a developer and developing an electrostatic latent image formed on the image bearing member, and a supplying member for contacting to the developer carrying member to supply the developer to the developer carrying member; and a control device for controlling Vdr and Vrs such that Vrs relative to Vdr increases in a direction of a polarity which is the same as a polarity of the developer with the decrease of an absolute value S, where S is a difference between a peripheral speed Sopc of a surface of the image bearing member and a peripheral speed Sdr of the surface of the developer carrying member, Vrs is a voltage applied to the supplying member, and Vdr is a voltage applied to the developer carrying member.03-04-2010
20110150513IMAGE FORMING APPARATUS - A charge bias causing the surface potential of a photosensitive drum to be lower than that in image formation is applied to a charge roller during a period in which the stop position of a rotary is moved from an unknown state to a home position to cause a developing bias to be applied to a developing roller to be smaller than that in the image formation.06-23-2011
20120201556IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD - An image forming apparatus includes a photoreceptor, a developing apparatus, a developing bias supply power source, a control section for controlling a developing bias, a density sensor, and an arithmetic section. When an image density adjustment operation is performed, the arithmetic section determines a print-time developing bias in accordance with a detection result obtained by detecting, by the density sensor, a plurality of image density adjustment toner images formed by changing a developing bias. The print-time developing bias is set by the control section when printing is performed. also, In a case where a previous print-time developing bias falls within at least a low range of a predetermined range of the developing bias, the arithmetic section determines the print-time developing bias to a value between a reference developing bias for a target image density and the previous print-time developing bias.08-09-2012
20120201555Image Forming Apparatus and Image Forming Method - An image forming apparatus of the invention includes; a cleaning member that collects liquid developer by cleaning a developer carrier; a first transporting path that moves the liquid developer collected by the cleaning member; an oscillating member that applies vibration to the liquid developer transported from the first transporting path; a developer supply unit that stores the liquid developer transported from a first transporting mechanism; a second transporting mechanism that includes a second transporting path that transports the liquid developer stored in the developer supply unit to a developer storage in a developing unit; and a control unit that adjusts a toner charge current applied to the toner charging unit and controls vibration applied to the oscillating member on the basis of the adjusted toner charge current.08-09-2012
20100303492Image Forming Apparatus - In an image forming apparatus, a first photoconductor drum for use in at least in a monochrome printing mode is located upstream, in a direction of transport of a medium, of a plurality of second photoconductor drums for use in a color printing mode. A transfer bias for each of transfer members is regulated in such a manner that a transfer bias applied in the monochrome printing mode between a second photoconductor drum located adjacently downstream of the first photoconductor drum and the corresponding transfer member is larger than that applied in the color printing mode. A developing bias for each of the development rollers is regulated in such a manner that an absolute value of a developing bias voltage applied to a development roller corresponding to the first photoconductor drum in the monochrome printing mode is smaller than that applied in the color printing mode.12-02-2010
20100086323IMAGE FORMING APPARATUS - An image forming apparatus includes: a supplying section for supplying developer; a first developing roller including plural magnetic poles and a first sleeve arranged rotatable to the first developing roller; a second developing roller including plural magnetic poles and a second sleeve arranged rotatable to the second developing roller, the second developing roller arranged adjacent to the first developing roller and parallel to the same; an electrode arranged between the first and second developing rollers; and a voltage applying unit for applying bias voltages each having different electric potential corresponding to the first developing roller, the second developing roller and the electrode, wherein an absolute value of the bias voltage to be applied to the electrode is larger than that of the bias voltage to be applied to the first developing roller and smaller than that of the bias voltage to be applied to the second developing roller.04-08-2010
20120063797DEVELOPING DEVICE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD - An image forming apparatus includes a latent image carrier to carry a latent image, a developing device having a toner carrier with first and second electrodes to develop the latent image by transferring the toner to a developing region between the toner carrier and the latent image carrier while causing the toner to hop between the first and second electrodes and attaching the hopping toner to the latent image, a pulsed power supply to output a first periodic pulse voltage having a mean potential the same as a normal toner charge and a second periodic pulse voltage, a smoothing circuit to make the first periodic pulse voltage smooth to generate a direct voltage, and a toner layer thickness regulator member to regulate, on receiving the direct voltage, a thickness of the toner layer in a region between a toner supply position at which toner is supplied and the developing region.03-15-2012
20110164892DEVELOPMENT DEVICE, PROCESS CARTRIDGE INCORPORATING SAME, AND IMAGE FORMING APPARATUS INCORPORATING SAME - A development device includes a developer container, a rotary developer carrier that is disposed facing the latent image carrier and including multiple outer electrodes arranged in a circumferential direction of the developer carrier, an inner electrode electrically insulated from the multiple outer electrodes, an insulation layer disposed between the inner and outer electrodes, and a surface layer overlaying the outer electrodes and electrically insulating the multiple outer electrodes from each other, a bias power source to generate electrical fields that change with time by applying a first and second bias voltages to the inner and outer electrodes, respectively, an electrical field adjuster to regulate the electrical fields in accordance with a thickness of the surface layer of the developer carrier, and a controller.07-07-2011
20100111551IMAGE FORMING APPARATUS AND METHOD FOR CONTROLLING SAME - An image forming apparatus has: a photoconductive drum that rotates; a developing roller that carries toner to be charged and to which a first voltage application portion outputting an AC voltage is connected; a contact member that makes contact with the photoconductive drum to remove residual toner; a detection portion for detecting occurrence of electric discharge between the developing roller and the photoconductive drum; and a developing unit that feeds toner to the developing roller, that supports the developing roller opposite the photoconductive drum with a gap secured in between, and that feeds toner to the developing roller with prescribed timing and for a prescribed time during electric discharge detection.05-06-2010
20100215389IMAGE FORMING APPARATUS AND METHOD OF CONTROLLING DEVELOPMENT ELECTRIC FIELD STRENGTH THEREIN - An image forming apparatus includes an image carrier, a developer carrier, a runout measurement information storage unit to store runout measurement information of the image carrier and the developer carrier, including runout amounts on the circumference of the image and developer carriers in a development area, a development gap measurement information storage unit to store information obtained by measuring a development gap when runout measurement points of the image and developer carriers face each other, and a development electric field strength control unit to obtain each development electric field strength based on the runout measurement information and the development gap measurement information, and determine control contents of development electric field strength control to cause the entire development electric field strengths to fall within an acceptable range of a target electric field strength to perform the control contents.08-26-2010
20100067932IMAGE FORMING APPARATUS - An image forming apparatus includes an image carrier; an exposure unit configured to form an electrostatic latent image on the image carrier; a developing unit including a toner containing unit configured to accommodate a predetermined amount of toner, a toner supply unit configured to supply replenishment toner into the toner containing unit, a stirring unit configured to stir the toner to impart electric charge to the toner, a toner carrying member configured to carry the toner charged by the stirring unit, and a bias applying unit configured to apply a developing bias to the toner carrying member to develop the electrostatic latent image formed on the image carrier with the toner carried by the toner carrying member; a density sensor configured to detect a density of a toner pattern developed by the developing unit; and a control unit configured to control an amount of the toner supplied to the toner containing unit.03-18-2010
20100021191IMAGE FORMING APPARATUS, DEVELOPING UNIT, AND COMPUTER SYSTEM - An image forming apparatus, for example, that is capable of accurately writing information into a developing unit or the like having an element is achieved. An image forming apparatus comprises: an attach/detach section to and from which a developing unit having an element into which information can be written and a developer containing section can be attached and detached; a photoconductor on which a latent image can be formed; a writing member for writing information into the element; and an AC voltage supply section for supplying an AC voltage. During a period from a start to an end of an image forming process, the writing member writes information into the element of the developing unit attached to the attach/detach section when the AC voltage supply section is not supplying an AC voltage.01-28-2010
20120308248ACTIVE BANDING CORRECTION IN SEMI-CONDUCTIVE MAGNETIC BRUSH DEVELOPMENT - An electronic development compensation method which is broadly applicable to SCMB development includes controlling image banding by actively correcting for mechanical development errors by modulating DC bias to a magnetic brush.12-06-2012
20090028593IMAGE FORMING APPARATUS - An image forming apparatus includes a charging device to electrically charge a photosensitive member, an exposure unit to expose the charged photosensitive member to light, a development device to develop, with a developer, a latent image formed on the photosensitive member by the exposure unit, and a development bias voltage generating circuit to apply a development bias voltage to the development device. The development bias voltage generating circuit includes a transformer, a capacitor connected to one end of the transformer, first-fourth switching elements, a power source to supply a voltage to the first and third switching elements, and a control unit to control an on and off action of the first to fourth switching elements and independently control the voltages applied by the power source to the first and third switching elements.01-29-2009
20120057891IMAGE FORMING APPARATUS - An image forming apparatus includes a latent image carrier; a latent image writer to write a latent image on the latent image carrier; a developing unit including a toner carrier having first and second electrodes insulated via an insulator member and a voltage applying unit to apply voltages to the first and second electrodes having a potential difference to generate first electric fields to cause the toner to hop from the toner carrier to the latent image carrier to develop a toner image; and a transfer unit to transfer the developed toner image to a transferring member. When alternating voltages having a same phase and same amplitude are applied to the first and second electrodes to form second electric fields between the latent image carrier and the toner carrier, the toner is discharged from the toner carrier to the latent image carrier in a toner discharge mode.03-08-2012
20120020688DEVELOPING DEVICE, IMAGE FORMING UNIT AND IMAGE FORMING APPARATUS PROVIDED WITH THE SAME - A developing device includes an applying portion for applying a bias at a first voltage value and a first frequency, to a toner bearing member during a development period in which toner particles are supplied to an image bearing member. A controller executes a removal control to remove attached matter adhering to a bearing surface of the toner bearing member during a non-development period. Upon executing the removal control, the controller first causes residual toner particles to separate from the bearing surface. Subsequently, the controller controls the applying portion to cause a second bias at a second voltage value higher than the first voltage value or at a second frequency higher than the first frequency to be applied to the toner bearing member while bringing a developer layer on a developer bearing member into contact with the bearing surface.01-26-2012
20120155901IMAGE FORMING APPARATUS - An image forming apparatus including a control portion which controls a bias to be applied to a charging roller for charging a photosensitive member to a predetermined potential or a developing roller for supplying toner to the photosensitive member, in which the control portion performs a developer install mode for controlling the bias to be applied to the charging roller or the developing roller during replenishment of toner to a developing container to be used for the first time, and at a time of the developer install mode, controls the bias to be applied to the charging roller or the developing roller so as to obtain a developing electric field (Vcont06-21-2012
20110182605IMAGE FORMING DEVICE AND METHOD OF ADJUSTING DENSITY OF FORMED IMAGE - An image forming device includes a toner supplying unit to supply the toner to a storage unit, a mixer to supply developer in the storage unit to a developing roller, a developer sensor to detect the amount of developer on the surface of the developing roller, a toner concentration sensor to detect toner concentration in the developer stored in the storage unit, and a control unit to adjust at least one of a developing bias and a rotation speed of the mixer based on a value detected by the developer sensor and a value detected by the toner concentration sensor, such that a printed image has uniform density.07-28-2011
20120134697DEVELOPMENT DEVICE AND IMAGE FORMATION APPARATUS - A development device includes an image carrier configured to develop an electrostatic latent image by using a developer, a development member configured to supply the developer to the image carrier, a developer supply member configured to supply the developer onto a surface of the development member, and a developer restriction member including a contact portion configured to form a developer layer on the surface of the development member while being in contact with the surface. A curvature radius R [mm] of the contact portion of the developer restriction member is 0.17 [mm] to 0.28 [mm], both inclusive, and an ASKER F hardness [°] of the developer supply member is 181.82×R+9.09≦F≦−250×R+130.05-31-2012
20120177390IMAGE FORMING UNIT AND IMAGE FORMING APPARATUS - An image forming cartridge comprises a developing unit configured to hold toner including a developing section configured to use the toner for developing and a supplying section configured to provide the toner to the developing section and a toner cartridge attachable to the developing unit, wherein the toner cartridge contains toner and supplies toner to the developing unit and the toner cartridge includes a stand-by charging unit configured to perform stand-by charge to the toner in the toner cartridge.07-12-2012
20120251146RATIO MODULATED PRINTING WITH DISCHARGE AREA DEVELOPMENT - Methods for printing are provided. In one aspect, the method includes providing a primary imaging member having engine pixel locations with a ratio modulated difference of potentials, establishing a first development difference of potential to form a first net development difference of potential between the first development difference of potential and the engine pixel location and providing a first charged toner such that the first toner develops at the engine pixel location according to the first net development difference of potential. Establishing a second development difference of potential that is greater than the first difference of potential proximate the engine pixel location such that a determined amount of second toner develops at the engine pixel locations. Wherein the range of first toner potentials is such that a determined range of ratios of first toner amounts and the determined second toner amount provide ratio modulated differences of potential.10-04-2012
20100008687IMAGE FORMING APPARATUS - An image forming apparatus including a latent image bearing member, a charger to evenly charge a surface of the latent image bearing member, an electrostatic latent image forming device to form an electrostatic latent image on the surface of the latent image bearing member, a developing device to develop the electrostatic latent image into a toner image using toner, a transfer bias application device to apply a transfer bias to an image transfer area where the latent image bearing member faces a recording medium, a pre-transfer neutralizing device to reduce an electric potential at a portion on the surface of the latent image bearing member, a surface electric potential detector to detect an electric potential at the surface of the latent image bearing member, and a radiation amount control device to control an amount of radiation from the pre-transfer neutralizing device based on a detection result obtained by the surface electric potential detector.01-14-2010
20090016755DEVELOPING UNIT AND DENSITY CONTROL METHOD IN ELECTROPHOTOGRAPHY - This invention relates to a developing unit for maintaining constant density in an electrophotographic imaging process. The developing unit has a developer roll, wherein the developer roll provides a surface and a first voltage is applied to the developer roll; a skive device, wherein the skive device is positioned in contact with the developer roll and a second voltage is applied to the skive device; a cleaning device for the developer roll, wherein the cleaning device is in contact with the developer roll; and an ink container, wherein the developer roll and the cleaning device are inside the ink container. It is preferred that a current measuring device is present to measure current flow between skive device and the developer, or a voltage meter is present to measure a voltage across a known resistor that is in series with the power supply to the skive device.01-15-2009
20120230714DEVELOPING APPARATUS - A developing apparatus including a developing container for containing developer, the developing container having an opening portion, a developer carrying member for carrying the developer at the opening portion, a detecting member for detecting a developer amount, the detecting member detecting a capacitance between the developer carrying member and the detecting member, and a force receiving portion for receiving a force and moving the developing container between a first position in which a developing operation is performed by the developer carrying member and a second position in which the developing operation is not performed, wherein the capacitance can be detected in the second position, and the detecting member is a rotatable developer supplying member for supplying the developer to the developer carrying member, the developer supplying member including a foam layer in which the developer can enter.09-13-2012
20080304846SEGMENTED ROLLER FOR FLOOD COATING SYSTEM - An electrostatographic apparatus and method of forming a toner image on a receiver using a segmented roller in order to improve transfer of a pigmented toner image to a receiver. The pigmented toner image is applied using the segmented roller and is then transferred to a receiver sheet.12-11-2008
20120328313IMAGE FORMING APPARATUS USING TWO-COMPONENT DEVELOPER - An image forming apparatus includes a magnetic roller voltage applier for a magnetic roller, a developing roller voltage applier for a developing roller and a controller for controlling the appliers. The controller controls the magnetic roller voltage applier to apply, to the magnetic roller, a first voltage for forcibly conveying a thin layer of toner held on the developing roller toward the magnetic roller for a first period required for one turn of the developing roller, and controls the developing roller voltage applier to apply, to the developing roller, a second voltage for causing toner on the developing roller to fly onto the image carrier for a second period when at least the forcible consumption electrostatic latent image faces a facing portion between the developing roller and the magnetic roller. At least parts of the first period and the second period are overlapped with each other.12-27-2012
20120148279WET-TYPE IMAGE FORMING APPARATUS - A wet-type image forming apparatus includes an image bearing member, a developer bearing member for bearing liquid developer containing toner and carrier liquid on the circumferential surface thereof, a bias applying unit for applying a developing bias to the developer bearing member, a first charging unit for charging the toner in the liquid developer to a first polarity before supplying the liquid developer to the image bearing member, and a second charging unit for reversely charging the toner in residual liquid developer remaining on the circumferential surface of the developer bearing member to a second polarity opposite to the first polarity after the development process. When V06-14-2012
20130022365IMAGE FORMING APPARATUS CAPABLE OF PRINTING LONG SHEETS - An image forming apparatus includes a separating unit for performing a stripping operation of forcibly returning toner particles carried on a toner bearing member to a developer bearing member, a sheet size discriminator for discriminating whether a sheet is a standard sized sheet or a long sheet, a determiner for determining whether or not there is any blank area of a predetermined length or longer in the sub scanning direction, where no toner image is to be substantially transferred, for each long sheet, and a controller for controlling the stripping operation. The controller causes the separating unit to perform the stripping operation at a developing timing of an electrostatic latent image corresponding to the blank area to be formed on the image bearing member when the sheet is a long sheet and when the blank area of the predetermined length or longer is present.01-24-2013
20080240758SYSTEMS AND METHODS FOR MOMENTUM CONTROLLED SCAVENGELESS JUMPING DEVELOPMENT IN ELECTROPHOTOGRAPHIC MARKING DEVICES - To generate a toner cloud in a development system, a first potential is applied to a donor roll for a first pulse time to project toner from the donor roll toward a photoreceptor, a second potential is applied to the donor roll for a second pulse time to slow the speed at which the toner is projected toward the photoreceptor; a third potential is applied to the donor roll for a third pulse time to hold toner between the donor roll and the photoreceptor; and a fourth potential is applied to the donor roll for a fourth pulse time to urge undeveloped toner to the surface of the donor roll. Voltages may also be applied for selectivity removing toner from a donor roll.10-02-2008
20080226320DEVELOPING UNIT AND IMAGE FORMING APPARATUS - A developing unit has a voltage-applicator (09-18-2008
20130142530IMAGE FORMING APPARATUS - 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.06-06-2013
20130094871IMAGE FORMING APPARATUS AND IMAGE FORMING SYSTEM - An image forming apparatus includes a developer bearing member configured to bear a developer to develop a latent image, a developer regulating member configured to regulate an amount of the developer carried on the bearing member, a voltage application unit that can apply a plurality of direct current voltages of different values between the bearing member and the regulating member, and a current detection unit that can detect a plurality of direct currents of different values flowing in the regulating member when the voltage application unit applies the plurality of direct current voltages, wherein the image forming apparatus sets a direct current voltage value Vb applied by the voltage application unit when developing the latent image, so that the following expression is satisfied: |Vb|>|Vbmin|, where Vbmin indicates a direct current voltage value when the direct current detected by the current detection unit is a minimum value.04-18-2013
20130129369IMAGE FORMING APPARATUS - An image forming apparatus is provided with a high-voltage substrate, a motor and a DC power source. The high-voltage substrate has a developing positive bias circuit and a developing reverse bias circuit which are connected to each other in parallel, in which the developing positive bias voltage is combined with developing reverse bias voltage to generate developing bias voltage. The high-voltage substrate includes a interruption switch for interrupting a reverse current from the motor to the developing reverse bias circuit in a case where an interlock switch is turned off at the time of emergency stop, in which, when the reverse current is interrupted by the interruption switch, electric power that is accumulated in the capacitor is supplied to the developing positive bias circuit to apply the developing positive bias voltage as the developing bias voltage to the developing roller for a given length of time.05-23-2013
20100316402DEVELOPING DEVICE - A developing device includes a developer bearing member for bearing a developer so as to develop an electrostatic image, a restricting member for restricting the amount of developer born on the developer bearing member, a detector for detecting information on the amount of developer existing between the developer bearing member and the restricting member, and a controller which can change a value of a voltage to be applied to the restricting member during image formation based on a result detected by the detector.12-16-2010
20130156454DEVELOPING DEVICE, IMAGE FORMING APPARATUS AND METHOD OF CONTROLLING DEVELOPING DEVICE - A developing device includes a development roller, a magnetic roller, a transformer, a switching portion, output control portion and a capacitor. The development roller is opposite a photoconductor drum. The magnetic roller performs, with a magnetic brush, the supply of a toner to the development roller and the removal of the toner. The transformer generates an alternating-current voltage applied to the development roller. The switching portion passes and interrupts a current to the transformer. The output control portion stepwise changes, when a duty ratio in switching is changed, the duty ratio a plurality of times from a first duty ratio to a second duty ratio. The capacitor has one end connected to the transformer and the other end connected to the switching portion.06-20-2013
20130183053DEVELOPING DEVICE, IMAGE FORMING APPARATUS, AND METHOD FOR CONTROLLING DEVELOPING DEVICE - A developing device includes a developing roller, a magnetic roller, a capacitor, a transformer, and a switching portion. The magnetic roller supplies toner to the developing roller or takes off the toner from the same. The capacitor is connected to a primary of the transformer, and the developing roller is connected to a secondary of the same. During a period while the voltage between electrodes of the capacitor is changing, the switching portion changes the duty ratio in a predetermined second time slot in which current flowing in the switching portion is smaller than that flowing in a first time slot.07-18-2013

Patent applications in class Bias control

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