Abstract: An image forming apparatus includes an image carrier, a charging member, a transferring member, a first voltage applying part, a current measuring part, a fan, a cleaning member and a controlling part. The controlling part carries out an aging operation rotating the image carrier and bringing the cleaning member in sliding contact with the image carrier before forming an image. The controlling part lengthens a running time of the aging operation in a case where a current value measured by the current measuring part is equal to or less than a first threshold value when the fan blows an outside air to the image carrier and the first voltage applying part applies voltage to one of the charging member and transferring member, in comparison with another case where the current value measured by the current measuring part exceeds the first threshold value.

Abstract: A charging device includes a charging member and a pulling device. The charging member charges a surface of an image carrier and includes a charging member body and axial-end members. The charging member body is arranged so as to face the image carrier and extends along an axial direction of a rotation shaft of the image carrier. The axial-end members are supported at both ends of the charging member body in the axial direction and do not extend through the inside of the charging member body in the axial direction. The pulling device pulls the charging member in the axial direction.

Abstract: The high-voltage output apparatus includes a voltage application part that applies a DC voltage to the charge member; a current detection part that detects a value of a current flowing in the image bearing member when the DC voltage is applied to the charge member; and a control part that calculates a plurality of discharge start voltages for the image bearing member, based on a plurality of current values detected by the current detection part as a result of the voltage application part applying a plurality of different DC voltages to the charge member, and controls the DC voltage applied to the charge member, using the plurality of calculated discharge start voltages. Consequently, a high-quality image can be formed by maintaining a potential on a photosensitive drum to be constant irrespective of the states of the circumstances and/or the drum layer thickness.

Abstract: A method includes moving a first end portion of a charging member with respect to a photoconductive member to obtain a first electrical discharge event corresponding to conduction of an electrical current from the charging member to the photoconductive member. The method also includes identifying a first adjustment value corresponding to a distance in which the first end portion moved toward the photoconductive member to obtain the first electrical discharge event. The method also includes moving a second end portion of the charging member with respect to the photoconductive member to obtain a second electrical discharge event corresponding to conduction of an electrical current from the charging member to the photoconductive member. The method also includes identifying a second adjustment value corresponding to a distance in which the second end portion moved toward the photoconductive member to obtain the second electrical discharge event.

Abstract: Engine response curves (RCs) can be used for streak compensation for printed documents. A feedback control paradigm can be included to effect RC compensation. Singular Value Decomposition (SVD) can be used to represent each RC in the collection of spatial RC data as a linear combination of basis vectors. RCs are approximated by selecting the first few basis vectors, the approximation aiding in noise rejection and reducing computation in the controller by reducing dimensionality of the RC data from gray levels to the number of SVD bases selected. An optimal subset of RCs is selectable from the set of approximated RCs by clustering the SVD weights, the clustered SVD weights producing TRCs that span all engine response RCs generated by a printer. Compensation RCs are constructible using reduced number of bases and clustered SVD weights.

Abstract: An image forming apparatus includes an image carrier, a charging member, a voltage applying part, a current measuring part and a controlling part. The image carrier carries a toner image. The charging member electrically charges the image carrier. The voltage applying part applies voltage to the charging member. The current measuring part measures current flowing into the charging member. The controlling part controls applied voltage of the voltage applying part. The controlling part decides, when a predetermined voltage is applied to the charging member for a predetermined time by the voltage applying part, if an increase quantity of the current measured by the current measuring part exceeds a predetermined threshold value, that at least one of the image carrier and the charging member is in an abnormal state.

Abstract: According to one embodiment, a motor control apparatus includes a timer to measure a period in which a job is not executed, a sensor to detect a temperature of a physical object, an acquisition part to acquire time information measured by the timer and temperature information detected by the sensor, and a drive control part that determines a current value of a motor provided in the physical object based on the time information and the temperature information acquired by the acquisition part, and controls the motor current value by applying a voltage level corresponding to the determined current value to a drive element of the motor.

Abstract: In an image forming apparatus, the charging bias supply circuit generates a second charging bias voltage that causes no positive discharge between the charging unit and the photoreceptor drum, during a recovery mode, the charging unit charges the surface of the photoreceptor drum upon application of the second charging bias voltage during the recovery mode, and the cleaning unit rubs the surface of the photoreceptor drum charged by the second charging bias voltage, during the recovery mode.

Abstract: An image forming apparatus may include a first and second mode. In the first mode, the image forming apparatus uses a second charging member to charge toner that remains on an intermediate transfer member and then transfers the charged, remaining toner to an image carrier in a primary transfer portion. In the second mode, the image forming apparatus transfers the remaining toner adhered to the second charging member in the first mode to the intermediate transfer member. Also in a second mode, the image forming apparatus controls so that a surface potential of the image carrier that reaches the primary transfer portion at a timing at which the remaining toner transferred to the intermediate transfer member passes through the primary transfer portion has a same polarity as that of a surface potential of the image carrier in the first mode and also has an absolute value smaller than that thereof.

Abstract: An image forming apparatus includes an image bearing member; a first charging member for electrically charging the image bearing member by being supplied with an oscillating voltage in the form of a DC voltage biased with a common AC voltage during image formation; a second charging member, provided downstream of the first charging member with respect to a movement direction of the image bearing member, for electrically charging the image bearing member by being supplied with the DC voltage and the common AC voltage during the image formation; detecting portion for detecting an AC current passing through the second charging member; and a setting portion for setting, on the basis of a detection result of the detecting portion when a predetermined AC voltage is applied to the second charging member during non-image formation, the common AC voltage applied to the first charging member and the second charging member during the image formation so that a discharge current between the second charging member and the

Abstract: An image forming device has: an image forming body on which an image is formed in a state in which the image forming body is charged; a charging device having plural discharge portions, and charging the image forming body by discharging of plural discharge portions; and a control section that, when forming the image on the image forming body, operates the plural discharge portions, and when not forming the image on the image forming body, switches between a state of operating some of the plural discharge portions and decreasing output of or stopping the discharge portions other than the some discharge portions, and a state of operating some other of the plural discharge portions and decreasing output of or stopping the discharge portions other than the some other discharge portions.

Abstract: In a high voltage power supplying apparatus, a pulse generation unit generates a pulse signal with a predetermined frequency. A piezoelectric transformer outputs a voltage in accordance with the frequency of the pulse signal. A detection unit detects an output voltage of the piezoelectric transformer. A control unit controls the pulse generation unit to change the frequency of the pulse signal by a predetermined value towards a frequency corresponding to a target voltage until the output voltage becomes equal to the target voltage. A storage unit stores data indicating the frequency when the output voltage reaches the target voltage. The control unit controls the output voltage to be equal to the target voltage by variably controlling the frequency of the pulse signal by a value smaller than the predetermined frequency from the frequency corresponding to the data stored in the storage unit.

Abstract: An image forming apparatus includes an image forming unit, a charging bias application section, a static eliminating bias application section, and a control section. In the case where the image forming unit causes an image carrier to be rotated without forming an electrostatic latent image on the image carrier, the control section performs a bias control to allow the charging bias application section to apply to a charging section a smaller charging bias than used in forming a toner image and allow the static eliminating bias application section to apply to a static eliminating section a smaller static eliminating bias than used in forming the toner image. The control section performs the bias control to increase respective values of the charging bias and the static eliminating bias every one revolution of the image carrier until the charging bias and the static eliminating bias in forming the toner image are reached.

Abstract: Apparatus and method for minimizing ghosting defects and process control instabilities for a printing system are disclosed. According to an exemplary embodiment, a controller retrieves uniformity measurements of an interdocument zone (IDZ) and sheet zone (SZ). In response to the uniformity measurements, a transfer current IDZ level is controlled to minimize differences in subsequent charging, photodischarge and/or development associated with the IDZ and SZ.

Abstract: An image forming apparatus includes: a photoconductor; a charger configured to charge the photoconductor, the charger including a discharge wire and a grid; a voltage applying circuit configured to generate charge voltage and apply the charge voltage to the discharge wire of the charger; a grid-current detector configured to detect a grid current passing through the grid; a controller configured to control the voltage applying circuit on the basis of a detection value detected by the grid-current detector so that the grid current is constant; an abnormal-discharge detector configured to detect an abnormal discharge occurring in the charger; and a suppression resistor configured to suppress abnormal discharge energy. The suppression resistor includes a first terminal and a second terminal. The first terminal is connected to the grid. The second terminal is connected to at least one of the grid-current detector and the abnormal-discharge detector.

Abstract: There is provided an image forming apparatus which includes multiple charging rollers and which can suppress accumulation of deposits such as external additives onto a charging roller without reducing productivity of the image forming apparatus. A changing voltage is applied to a first charging roller. A voltage obtained by superimposing an alternating voltage on a direct voltage is applied to a second charging roller disposed on the downstream side of the first charging roller in the rotation direction of a photosensitive member. During image formation, the changing voltage applied to the first charging roller is changed so that the magnitude relationship between the potential of the photosensitive member which has been charged by using the first charging roller and which has reached a position at which the photosensitive member is charged by using the second charging roller and the direct voltage applied to the second charging roller is alternately switched.

Abstract: An image forming apparatus includes an image bearing member on which a developer image is formed, a developer bearing member configured to develop a surface of the image bearing member, and a cleaning member configured to clean a residual developer remaining on the surface of the image bearing member, wherein, when an image forming operation is interrupted, the image forming apparatus is capable of performing a recovery operation before resuming the image forming operation, and wherein the image forming apparatus is capable of, during the recovery operation, a potential difference between a potential applied to the developer bearing member and a surface potential of a non-image area within the surface of the image bearing member greater than that during the image forming operation according to a predetermined value such that the developer on the image bearing member is moved to the developer bearing member.

Abstract: A cleaning system has a composite photoreceptive imaging member having a support layer, an electrically conductive layer interfacing with the support layer, a photoconductive charge generation layer interfacing with the electrically conductive layer and generating charge holes and electrons in response to exposure to electromagnetic radiation; a charge transport layer that allows charge holes to migrate from the charge generation layer to the outer surface while resisting migration of electrons from the charge generation layer to the outer surface and a cleaning blade member having a cleaning surface layer against the electrostatic surface to at least in part remove toner and debris from the outer surface. The cleaning surface layer has a first material and a second material that are combined in proportions that cause a triboelectric charge to be formed on the outer surface having a difference of potential of between zero and minus 20 volts.

Abstract: An image forming device includes each of developing devices including an image carrying part, a charging part that charges the image carrying part, a developing part on which a developing voltage is applied and which attaches developer to the image carrying part to develop the electrostatic latent image, and a control part that controls each of the developing devices. The developers are a white developer and other color developers, one of the developing devices using the white developer being defined the white developing device, the others using the other color developers being defined the non-white developing devices, and a developing potential difference of the white developing device is smaller than other developing potential differences of the non-white developing devices, the developing potential difference being defined between the developing voltage and potential of the image carrying part of the each developing device.

Abstract: A charging device includes a charger facing a rotatably supported image carrier and configured to charge the image carrier on which an electrostatic latent image is to be formed, and a movement mechanism configured to move the charger between a charging position at which the charger is close to the image carrier and a retracted position at which the charger is retracted away from the image carrier. The movement mechanism includes a support member supporting the charger that has been moved to the retracted position by the movement mechanism, and a movable member configured to move when a driving force from a drive source is transmitted thereto. The movable member moves to the charging position or the retracted position when the movable member is moved in a direction of a rotational axis of the image carrier while being in contact with the support member.

Abstract: An image forming apparatus includes: a photosensitive member driven rotary; a charging unit configured to charge the photosensitive member; an exposure unit configured to form an electrostatic latent image on the photosensitive member by exposing the charged photosensitive member; a detecting unit configured to detect a current flowing between the charging unit and the photosensitive member; and a correction unit configured to determine a fluctuation location and a fluctuation amount of the charged potential of the photosensitive member, according to a fluctuation amount of the current detected by the detecting unit, and to correct an amount of light irradiated by the exposure unit onto the photosensitive member at the fluctuation location of the charged potential according to the determined fluctuation amount of the potential.

Abstract: The high-voltage output apparatus includes a voltage application part that applies a DC voltage to the charge member; a current detection part that detects a value of a current flowing in the image bearing member when the DC voltage is applied to the charge member; and a control part that calculates a plurality of discharge start voltages for the image bearing member, based on a plurality of current values detected by the current detection part as a result of the voltage application part applying a plurality of different DC voltages to the charge member, and controls the DC voltage applied to the charge member, using the plurality of calculated discharge start voltages. Consequently, a high-quality image can be formed by maintaining a potential on a photosensitive drum to be constant irrespective of the states of the circumstances and/or the drum layer thickness.

Abstract: This disclosure provides methods and systems for troubleshooting charging and photoreceptor failure modes associated with a xerographic process. Specifically, according to an exemplary method the photoreceptor decay behavior, with and without the effects of depletion, are quantified and used to determine a performance state of one or more of the charging stations and the photoreceptor surface.

Abstract: An image-forming apparatus includes an image carrier that has an electrically chargeable film formed on a surface thereof and that carries an image and a charging section that charges a surface of the film on the image carrier. The charging section includes a first charging member that applies a direct-current voltage between the first charging member and the image carrier and a second charging member that applies a direct-current voltage between the second charging member and the image carrier to charge the film on the image carrier to a predetermined surface potential after the first charging member charges the film on the image carrier. The voltage applied by the first charging member is decreased such that the surface potential of the image carrier after the voltage is applied by the first charging member is decreased as the film on the image carrier becomes thinner.

Abstract: A charging device includes a charging member to charge an image bearing member; an applying device configured to apply to the charging member a charging bias voltage comprising a DC voltage component and an AC voltage component; an AC current detector; a DC current detector; and a controller. The controller determines a saturation peak-to-peak voltage V0 at which the detected DC current saturates when a peak-to-peak voltage of the AC voltage is increased, calculates a relational expression using only a detected AC current when a peak-to- peak voltage which is not more than the saturation peak-to-peak voltage V0 is applied, and determines the peak-to-peak voltage of the AC voltage applied to the charging member in an image forming operation on the basis of the relational expression and a detected AC current when a peak-to-peak voltage higher than the saturation peak-to-peak voltage V0 is applied.

Abstract: An image forming apparatus for printing an image on a medium, including: a first image carrier; a second image carrier disposed downstream of the first image carrier in a traveling direction of the medium; a first charging member configured to charge the first image carrier; a second charging member configured to charge the second image carrier; and a control unit configured to execute a monochrome printing mode in which a monochromic image is formed on the medium using the first image carrier and the first charging member and a color printing mode in which a color image is formed on the medium using the second image carrier and the second charging member. In the monochrome printing mode, the control unit makes an absolute value of an electric surface potential of the second image carrier larger than an absolute value of an electric surface potential of the first image carrier.

Abstract: An image forming apparatus according to an embodiment includes a charging device that charges an electric charge to an image carrier, a developing device supplying the image carrier with a developer, and a transfer device that transfers a toner image formed on the image carrier by a developing device onto a recording medium. The apparatus further includes a control unit, discriminates between a first mode of forming an image on a first recording medium of a first thickness and a second mode of forming an image on a second recording medium thinner than the first recording medium to control a developing contrast electric potential, and controls a magnitude of the developing contrast electric potential in the second mode so as to be lower than the first mode.

Abstract: An image forming apparatus includes: a first image forming unit for a monochrome printing including a first photosensitive member for black, a first charging member and a first collection member; a second image forming unit for a multi-color printing including a second photosensitive member for a color, a second charging member and a second collection member; and a control device configured to, at the color printing mode, apply a first charging bias to the second charging member and apply a first bias having a reverse polarity to a charged polarity of developer to the first and second collection members, and at the monochrome printing mode, apply a second charging bias to the second charging member, apply a second bias having the reverse polarity to the first collection member and apply a third bias to the second collection member.

Abstract: An image forming apparatus includes a photosensitive member; a charging device for electrically charging the photosensitive member; an exposure device for exposing to light the photosensitive member charged by the charging device to form an electrostatic image on the photosensitive member; a developing device for developing the electrostatic image on the photosensitive member with toner to form a toner image; a transfer portion for transferring the toner image from the photosensitive member onto an image receiving member; a toner charging portion, disposed upstream of the charging device and downstream of the transfer portion with respect to a rotational direction of the photosensitive member, for electrically charging the toner remaining on the photosensitive member without being transferred onto the image receiving member; and control portion for controlling the charging device and the exposure device so that a stripe-shaped electrostatic image is repeatedly formed in substantially parallel to a longitudina

Abstract: A developing device includes a developer supplying member for supplying developer; and a developer supporting member for supplying the developer supplied from the developer supplying member onto a static latent image supporting member. The developer supplying member includes an outer circumferential portion having an electrical resistivity between 1.2×104 and 1.0×108?.

Abstract: An image forming apparatus including: a plurality of photosensitive drums; a plurality of scorotron chargers provided for the plurality of photosensitive drums, respectively, a voltage application circuit commonly connected to the plurality of scorotron chargers, a plurality of wires provided for the plurality of scorotron chargers, respectively; a plurality of grid electrodes provided for the plurality of scorotron chargers, respectively; at least one of current detecting units provided for at least one of the plurality of grid electrodes, respectively, and at least one of the current detecting units detecting grid current which flows into at least one of the grid electrodes, respectively; and a control device configured to control the voltage application circuit such that at least one of the grid currents detected by at least one of the current detecting units become equal to or higher than a reference value.

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 for forming an image on a sheet includes an image bearing drum; a charging member for charging the drum by applying of a voltage while contacting to the drum; an AC voltage generating unit for generating and applying an AC voltage to the charging member; a state detector for detecting a state of the apparatus; a discharge current detector for detecting a discharge current between the charging member and the drum; a discharge current control unit for controlling the AC voltage generating unit on the basis of a result of detection of the discharge current detector; a discriminating unit for discriminating whether to calibrate the discharge current detector before formation of the image, in accordance with a result of detection of the state detector.

Abstract: An image forming apparatus includes a rotatable image bearing member including an electroconductive base member and a photosensitive member formed on the electroconductive base member; a contact charging device for electrically charging the photosensitive member; a DC voltage applying device for applying a DC voltage to the contact charging device; an exposure device for exposing the charged photosensitive member to light; and a current detecting device for detecting a current passing from the contact charging device to the electroconductive base member of the image bearing member.

Abstract: A method of charging a photoreceptor (3) includes a first corona charging unit (2) a first corona electrode (4), a first shell electrode (6), and a first high voltage power supply (22). The shell electrode is connected through a resistor to ground and the high voltage power supply is connected to the first corona electrode. A second corona charging unit (10) has a second corona electrode (12), and a first grid electrode (14) connected to a second shell electrode (16). A first corona current from the first high voltage power supply to the first corona electrode and a return current from the first shell electrode to ground is sensed and a voltage on the first high voltage power supply is adjusted to maintain a constant difference. The first corona charging unit charges the photoreceptor to at least 63% of the desired voltage and the second corona charging unit charges the photoreceptor to within 10% of the desired voltage.

Abstract: An image forming apparatus having; an electrostatic latent image support; a charger for charging the electrostatic latent image support; an exposure unit for exposing the electrostatic latent image support with a light beam to form an electrostatic latent image; a development unit for developing the electrostatic latent image into a toner image; a sheet feeding unit for feeding a recording sheet in an image forming operation; a transfer member for transferring the toner image to the recording sheet; a fuser for fusing the toner image onto the recording sheet; and a high-voltage power supply circuit for, in an image forming operation, applying a plurality of bias voltages at least to the charger and to the development unit, wherein the high-voltage power supply circuit supplies a high voltage only to the charger in an operation in an ion generation mode so as to cause the charger to generate ions.

Abstract: A system for charging a photoreceptor (3) includes a first corona charging unit (2) a first corona electrode (4), a first shell electrode (6), and a first high voltage power supply (22). The shell electrode is connected through a resistor to ground and the high voltage power supply is connected to the first corona electrode. A second corona charging unit (10) has a second corona electrode (12), and a first grid electrode (14) connected to a second shell electrode (16). A first corona current from the first high voltage power supply to the first corona electrode and a return current from the first shell electrode to ground is sensed and a voltage on the high voltage power supply is adjusted to maintain a constant difference. The first corona charging unit charges the photoreceptor to at least 63% of the desired voltage.

Abstract: An image forming apparatus includes a rotatable drum, a charging section for charging the drum, a latent image forming section, a potential detector, a phase detector, and a controller. The charging section includes a first carrying member and a second carrying member for carrying electroconductive magnetic particles. The second carrying member is disposed downstream of said first carrying member. The latent image forming section forms a latent image on the drum, and is disposed downstream of the charging section. The potential detector detects a surface potential of the drum, and is disposed downstream of the charging section. The phase detector detects information relating to a rotational phase of the second carrying member. The controller controls voltages applied to the first carrying member and to the second carrying member, on the basis of a result of detection by the potential detector and a result of detection by the phase detector.

Abstract: An image forming apparatus has first and second image carriers that are configured by positively-charged single layer type electrophotographic photoreceptors, and a controller that controls an operation for charging or destaticizing circumferential surfaces of these image carriers. The controller switches between a first mode for causing the first and second image carriers to perform image formation while rotating these image carriers, and a second mode for causing only the first image carrier to perform image formation while rotating the first and second image carriers. In the second mode, the second image carrier is applied with a charging bias and subjected to a destaticizing operation without undergoing a developing operation. The first image carrier is applied with the charging bias and subjected to the developing operation and the destaticizing operation.

Abstract: The image forming apparatus is capable of executing a color mode for forming images of a plurality of colors using the plurality of developer bearing members, and a mono-mode for forming images of mono color using one developer bearing member of the plurality of developer bearing members. The control unit, when the color mode is executed, determines the charging bias and, the first laser power and the second laser power for respective image bearing members, based on information about the plurality of image bearing members. The control unit, when the mono-mode is executed, determines the charging bias and, the first laser power and the second laser power to image bearing member for mono-mode, based on information about image bearing member for mono-mode.

Abstract: An image forming apparatus includes a photosensitive drum, a charging roller, a transfer roller, a first bias application unit, a second bias application unit, and a control unit. The charging roller contains an ion conductive material. The first bias application unit applies a first bias to the charging roller. The second bias application unit applies a predetermined bias to the transfer roller. The control unit controls the first bias application unit not to apply the first bias to the charging roller in a non-image forming period in which a toner image is not formed on the photosensitive drum. The control unit controls the second bias application unit to apply the second bias, which is a bias that can electrically charge the surface of the photosensitive drum, to the transfer roller in the non-image forming period.

Abstract: A power source includes a charging voltage generation unit configured to generate a charging voltage to charge an image bearing member, a developing voltage generation unit configured to generate a developing voltage to develop an electrostatic latent image formed on the image bearing member, a control unit configured to control an output from the developing voltage generation unit, and a correction unit configured to correct an operation of the control unit based on an output from the charging voltage generation unit.

Abstract: An image formation device for forming an image by an electrophotographic process includes a charge voltage controller configured to control an application charge voltage to be applied to a charge member, a transfer voltage controller configured to control a transfer voltage to be applied to a transfer member, a charge current detector configured to detect a charge current flowing through the charge member, and a controller configured to determine the application charge voltage according to the application charge voltage and the detected charge current, both detected when the transfer voltage controller applies a predetermined transfer voltage.

Abstract: In an image-forming device, each of the N chargers charges the opposed photoconductor with a discharge. The voltage applying unit applies voltages to the N chargers, individually. The abnormal discharge detecting unit detects an occurrence of an abnormal discharge at least one of the N chargers. The voltage detecting unit detects first voltages applied to the N chargers before the occurrence of the abnormal discharge is detected, and second voltages applied to the N chargers after the occurrence of the abnormal discharge is detected. The calculating unit calculates a difference between the first voltage and the second voltage for each of the N chargers. The identifying unit identifies one charger as a charger at which the abnormal discharge is occurring. The difference between the first voltage and the second voltage applied to the one charger is the greatest among the differences.

Abstract: The high-voltage output apparatus includes a voltage application part that applies a DC voltage to the charge member; a current detection part that detects a value of a current flowing in the image bearing member when the DC voltage is applied to the charge member; and a control part that calculates a plurality of discharge start voltages for the image bearing member, based on a plurality of current values detected by the current detection part as a result of the voltage application part applying a plurality of different DC voltages to the charge member, and controls the DC voltage applied to the charge member, using the plurality of calculated discharge start voltages. Consequently, a high-quality image can be formed by maintaining a potential on a photosensitive drum to be constant irrespective of the states of the circumstances and/or the drum layer thickness.

Abstract: The image forming apparatus calculates a surface voltage of an image bearing member based on a first charge start voltage, which is obtained when a first voltage application section applies a first DC voltage to a charge section, and a second charge start voltage, which is obtained when a second voltage application section applies a second DC voltage to the charge section. This allows a high-quality image to be formed irrespective of a change in circumstance or drum layer thickness.

Abstract: An image forming apparatus includes an application unit that applies to a holding unit a voltage that generates a potential difference between the holding unit and a photoconductor member such that a toner image is developed on the photoconductor member, the potential difference causing toner included in a two-component developer, held by the holding unit, to transfer from the holding unit to the photoconductor member, and a controller that controls the application unit, subsequent to an expiration of an image quality assurance period throughout which a predetermined image quality is assured, such that the potential of the holding unit is decreased in step with wear of the photoconductor member.

Abstract: An image forming apparatus including: one or a plurality of photosensitive drums; a plurality of chargers each having a grid, a voltage applying unit generating a charging voltage; a plurality of grid constant voltage circuits, each of the plurality of grid constant voltage circuits including: a voltage detecting unit that detects a voltage based on a grid voltage which is generated in the grid; a first current detecting unit detecting a first current; a voltage control line making the grid voltage constant; and an operation control device performing a feedback control such that the detected voltage has a predetermined voltage value; at least one of a second current detecting units detecting a second current flowing; and a controller controlling the voltage applying unit such that a sum of the first current and the second current corresponding to one of the plurality of chargers becomes a predetermined current value.

Abstract: An image forming apparatus includes: a charging unit which charges a surface of an image bearing member by contacting the image bearing member with a charging member to which a charging bias is applied, the charging bias being a voltage obtained by superimposing an AC voltage on a DC voltage; an electrostatic latent image forming unit which forms an electrostatic latent image on the surface of the image bearing member which is charged by the charging unit; a developing unit which develops the electrostatic latent image by using a developing bias formed by the voltage obtained by superimposing the AC voltage on the DC voltage; and a control unit which performs changing control of an AC frequency of the charging bias while maintaining a frequency ratio of an AC frequency of the developing bias to be an integral multiple of the AC frequency of the charging bias.

Abstract: In an electrophotographic image forming apparatus employing a contact development system, contact of a development roller against a photosensitive drum is started while forming an electrostatic latent image of a detection pattern for detection in each individual apparatus, and a developed toner image is detected at a predetermined position. At this time, a time from the time when contact of the development roller was started until the time when the toner image was detected is measured, and a delay time from a time when contact operation of the development roller was started until a time of actual contact is calculated by subtracting the time needed until the developed toner image reaches the detection position. The time when contact of the development roller is started is delayed by this time. The same sort of control is also performed for the separation time.