Abstract: An image forming apparatus comprises: an image processor to convert image data based on a conversion condition; an image forming unit to form an image based on the converted image data using a replaceable member; a memory to store the image data and the converted image data; a sensor to perform measurement of a test image; and a controller. If the replacement of the replaceable member is detected while forming images, the controller controls the image forming unit to form the test image and generates the conversion condition based on a result of the measurement of the test image. If the replacement of the replaceable member is detected while forming the images, the controller further controls the image processor to convert the image data stored in the memory based on the generated conversion condition.

Abstract: A remaining-toner-amount detecting device includes: first sensor disposed at a supply channel for a toner; a second sensor disposed at a location different from the supply channel; detection processing that compares a capacitance detected by the first sensor with a determination threshold value to detect a toner end; and a memory that stores a capacitance detected by the second sensor in an initial period as initial reference data, and a capacitance detected by the second sensor after part replacement as post-replacement reference data. The detection processing circuitry sets, based on the initial reference data, the determination threshold value as an initial determination threshold value in the initial period, and re-sets the determination threshold value, from the initial determination threshold value, to a value based on the post-replacement reference data, as a post-replacement reference data after the part replacement.

Abstract: In response to determining that image forming in a color mode is performed on a first sheet and then image forming in a monochrome mode is successively performed on the second sheet, perform charging bias reduction processing gradually reducing a charging bias from first to second charging bias and developing bias reduction processing of gradually reducing a developing bias from first to second developing bias during a first inter-sheet period after the first sheet passes a first photosensitive drum and before the second sheet reaches the first photosensitive drum, and perform separation processing such that an execution period of the separation processing overlaps at least one of an execution period of the charging bias reduction processing and an execution period of the developing bias reduction processing, the separation processing being processing of controlling a moving mechanism to move a first developing roller from a contact position to a separation position.

Abstract: An image forming apparatus includes a plurality of image forming units, a developing voltage power supply, a current detection unit, and a control unit. The image forming units form an image by superimposing a toner image of a same color and a same type, and substantially same development conditions are set to evenly divide an image density among the image forming units. The control unit detects whether there is an anomaly in the image forming unit based on detecting a DC component of developing current, being either of current flowing through a non-exposed portion of an image carrier during image formation, and current flowing through an exposed portion of the image carrier. When an anomaly is detected in any image forming unit, the control unit inhibits use of the image forming unit, and resets the development conditions to evenly divide an image density among the usable image forming units.

Abstract: An image forming apparatus includes a plurality of image forming units, a developing voltage power supply, a density detection device, a current detection unit, and a control unit. The plurality of image forming units form an image and substantially same development conditions are set to evenly divide an image density among the image forming units. The control unit detects whether there is an anomaly in a developing device, based on a toner charge amount calculated based on a DC component of developing current when a reference image is formed on an image carrier by each of the developing devices and a density of the reference image. When an anomaly is detected in any of the developing devices, the control unit inhibits use of the image forming unit including the developing device, and resets the development conditions to evenly divide the image density among the usable image forming units.

Abstract: In an image forming apparatus, a first photosensitive drum is disposed upstream of a second photosensitive drum in a conveyance direction. Each of first and second developing rollers is movable between a contact position contacting a corresponding photosensitive drum and a separated position separated from the corresponding photosensitive drum. In a first case where a color print process is executed, a first moving mechanism starts moving the first developing roller toward the contact position, a manual feed roller starts picking up the sheet on a manual feed tray, and a second moving mechanism starts moving the second developing roller toward the contact position. In a second case where the monochrome print process is executed, the manual feed roller starts picking up the sheet on the manual feed tray, and the second moving mechanism starts moving the second developing roller toward the contact position.

Abstract: An image-forming apparatus includes: a process motor; a developing motor; a sheet conveying device; first and second photosensitive drums rotatable by a driving force from the process motor; first and second developing rollers and first and second cams each rotatable by a driving force from the developing motor; a switching mechanism, and a controller. Rotation of each cam causes each developing roller to move between a contact position in contact with the corresponding photosensitive drum and a separated position away from the corresponding photosensitive drum. The controller allows the switching mechanism to transmit the driving force from the developing motor to each cam such that a timing of contact between the second developing roller and the second photosensitive drum in a low speed mode is coincident with or earlier than a timing of contact between the second developing roller and the second photosensitive drum in a normal mode.

Abstract: An image forming apparatus includes a photoconductor, a charger; a charge voltage applier that applies first and second charge voltages to the charger; an exposure device; a development device; a development voltage applier that applies first and second development voltages to the development device; a transfer device; a fixing device; a motor that drives the photoconductor simultaneously with at least one of the transfer device, the fixing device, and the transporter; and a controller. When the motor is driven for image formation, the first charge voltage and the first development voltage are respectively applied to the charge voltage applier and the development voltage applier. When the motor is driven for an operation other than image formation, the second charge voltage and the second development voltage are respectively applied to the charge voltage applier and the development voltage applier.

Abstract: A mode controller outputs a characteristic value according to a DC component of a developing current measured by an ammeter at a predetermined measurement timing. The measurement timing is defined as a timing at which a non-image forming region of a surface of a photosensitive drum is located opposite to a developing roller in the entirety of an axial direction and an electric field in a direction in which a toner moves from the photosensitive drum toward the developing roller by a potential difference between a surface potential of the photosensitive drum and the DC component of a developing bias is formed in a developing nip part. A determining section determines an execution timing for a charge amount acquisition operation according to the characteristic value output by the mode controller.

Abstract: A recording apparatus includes a recording head that performs recording on a medium, a transport belt that has an clinging surface that cling the medium, and transports the medium to a position facing the recording head, a first charging unit that is in contact with the transport belt to frictionally charge the clinging surface, and a second charging unit that applies a voltage to the transport belt to charge the clinging surface, in which a control unit, which switches between charging of the clinging surface by the first charging unit and charging of the clinging surface by the second charging unit, switches between the charging of the clinging surface by the first charging unit and the charging of the clinging surface by the second charging unit, according to a state of a surface of the medium, which is in contact with the clinging surface.

Abstract: First correction data for use in a first printing mode is generated by image density measurement in the first printing mode, and second correction data for use in a second printing mode, which is different from the first printing mode in peripheral speed ratio of a developing roller to a photosensitive drum, is generated by image density measurement in the second printing mode. First processing for generating first and second correction data for the first and second printing modes, respectively, by density measurement, or second processing for generating the first correction data by density measurement and generating the second correction data using the generated first correction data and a difference in image density between the first printing mode and the second printing mode is executed. The first processing is executed when a predetermined condition is satisfied.

Abstract: A method of balancing current in a developer roller is described. The method includes pulsing voltage to a squeegee roller and a cleaner roller. The pulsed voltage yields a differential voltage at the developer roller after impression. The method also includes pulsing compensating voltage to at least one of the squeegee roller or the cleaner roller to reduce or cancel an accumulated developer current imbalance of the developer roller. The compensating voltage pulses include pulses before or after the impression.

Abstract: An image forming apparatus includes a rotatable intermediate transfer member; a first image forming portion having a first photosensitive member which rotates, a first developing unit, and a first charge eliminating unit; a second image forming portion that is located on a downstream side of the first image forming portion in a rotational direction of the intermediate transfer member, and that has a second photosensitive member which rotates, a second developing unit, and a second charge eliminating unit; a transfer unit; and a switching unit that switches a light amount of the second charge eliminating unit when a usage amount of the second image forming portion reaches a predetermined amount to a value that is greater than a light amount of the first charge eliminating unit when a usage amount of the first image forming portion reaches the predetermined amount.

Abstract: In an image forming operation of transferring one developer image to a recording material, when a plurality of image forming portions include a non-image forming portion that is an image forming portion which does not form a developer image on an image bearing member, applying means for applying a charging bias to a charging member which comes into contact with and charges the image bearing member applies a second charging bias to the charging member in the non-image forming portion, the second charging bias having a same polarity as a first charging bias for forming a developer image and being a voltage equal to or lower than a discharge start voltage.

Abstract: An image forming apparatus includes an apparatus body, an image bearing member, a developing unit, a power supply, and a contact portion. The developing unit includes a developing container configured to store developer, a developer bearing member configured to rotate while bearing the developer stored in the developing container, and a developing magnet provided within the developer bearing member and comprising a plurality of magnetic poles in a circumferential direction. The developing unit is removably provided to the apparatus body. The contact portion electrically is connected with the power supply. The developing unit comprises a conductive member which is made of a conductive resin comprising a fixing portion fixing the developing magnet so that the magnetic poles of the developing magnet are fixed unrotatably with respect to the developing container. The conductive member is provided to electrically connect the contact portion with the developer bearing member.

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.

Abstract: An image forming apparatus includes a controller to execute a first mode for forming a toner image on a recording medium, in which a maximum toner carrying amount per unit area is a first maximum toner carrying amount, and a second mode for forming a toner image on the recording medium, in which the maximum toner carrying amount per unit is a second maximum toner carrying amount larger than the first maximum toner carrying amount. In the first mode, the controller sets a circumferential speed ratio of the toner bearing member against an image bearing member at a first circumferential speed ratio, and in the second mode the controller sets the circumferential speed ratio at a second circumferential speed ratio higher than the first circumferential speed ratio. The controller executes the second mode upon an order of the second mode by an operator.

Abstract: An image forming apparatus is provided. The image forming apparatus includes a sensor configured to sense a toner concentration, a processor configured to determine at least one of a coring level and a total area coverage (TAC) level according to the detected toner concentration, and an image former configured to print the rendered print data.

Abstract: An image forming apparatus includes a charger, a photoconductor, a charging high-voltage power supply, and circuitry. The charging high-voltage power supply supplies a charging bias to the charger and generates an output value feedback voltage representing a voltage value corresponding to an output current value from the charger to the photoconductor. The circuitry extracts a minimum value of the output value feedback voltage based on the output value feedback voltage generated in a given time. The circuitry calculates a maximum gap value between the charger and the photoconductor based on the minimum value. The circuitry calculates an AC voltage value based on the maximum gap value. The circuitry adds the AC voltage value to a DC voltage value to generate and transmit an output value control signal to the charging high-voltage power supply, to cause the charging high-voltage power supply to adjust the charging bias.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.