Abstract: An image forming apparatus includes a toner image forming device that forms a toner image by using at least one of a plurality of toners that include a color toner and a first transparent toner; an intermediate transfer body to which the toner image is transferred; a second transfer unit that transfers the toner image to a recording medium; and a controller that acquires characteristic information that represents a characteristic of in-plane resistance variation of a currently-used recording medium before the toner image forming device forms the toner image, and if the characteristic information indicates that the in-plane resistance variation of the currently-used recording medium is larger than a predetermined value, controls the toner image forming device so that the toner image forming device forms a transparent toner image in such a way that a color toner image is superimposed on the transparent toner image on the intermediate transfer body.

Abstract: An image forming apparatus includes a rotatable image bearing member for bearing a toner image; a transfer member constituting a transfer portion for transferring the toner image formed on the image bearing member onto a recording material; a voltage source for applying, to the transfer member, a voltage in the form of superimposed DC voltage and AC voltage; a controller for controlling the voltage source such that a duty ratio of the AC voltage is changed in accordance with a kind of the recording material; and an executing portion for executing an operation in an image forming mode in which the toner image is transferred from the image bearing member onto the recording material with the duty ratio controlled by the controller.

Abstract: 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.

Abstract: A transfer device includes a transfer belt, a transfer roller and a tension roller over which the transfer belt is passed in a tensioned condition and which is made to be in an electrically floated state; it also includes a guide member that is installed in the vicinity of the tension roller. A control section, in transfer processing, controls a first switch so that the guide member is in a grounded state while controlling a second switch so that an electric current being caused to flow to the transfer roller becomes a first electric current; and in cleaning processing, controls the first switch so that the guide member is in an electrically floated state while controlling the second switch so that an electric current being caused to flow to the transfer roller becomes a second electric current.

Abstract: An image forming apparatus is constituted by an image carrying member movable while carrying a toner image, or a recording material carrying member movable while carrying a recording material onto which a toner image is to be transferred; a contact member movable while contacting the image carrying member or the recording material carrying member; and a voltage adjusting member for adjusting a voltage to be applied to the contact member so that an absolute value of the voltage when a state of the image carrying member or the recording material carrying member and the contact member is changed from a rest state in which these members are resting to a moving state in which these members are moving is larger than an absolute value of the voltage in the rest state.

Abstract: An image forming apparatus includes: a first image forming unit including a first transfer unit forming a first nip with a first photosensitive drum for black; a second image forming unit including a second transfer unit forming a second nip with a second photosensitive drum for a color; and a control device which, when a first sheet and a second sheet are continuously conveyed in corresponding order by the conveyance belt at the monochrome mode, is configured to supply a first transfer current for a first time period during which the first sheet or the second sheet pass through the second nip and supply a second transfer current, which is smaller than the first transfer current, for a second time period that is a sheet interval between the first sheet and the second sheet.

Abstract: An image forming apparatus, including: a rotatable image bearing member; a developing unit configured to supply a developer onto the image bearing member; a transfer unit configured to transfer the developer on the image bearing member to a recording medium by a transfer voltage being applied to the transfer unit by a voltage applying unit; and a cleaning unit configured to remove the developer on the image bearing member, wherein when the apparatus stops an image forming operation halfway, the apparatus executes a recovery operation in which the image bearing member is rotated while the voltage applying unit applies a voltage to the transfer unit so that a part of the developer remaining on the image bearing member is once transferred from the image bearing member to the transfer unit, transferred again from the transfer unit to the image bearing member, and then removed by the cleaning unit.

Abstract: An image forming apparatus can form a high-quality image without a toner image being rubbed with and transferred onto a sheet.

Abstract: An image forming apparatus includes: an image bearing member; a toner image forming portion; a transfer member; a power source configured to apply a voltage to the transfer member so that a level of the voltage in a non-sheet-passing period in which a recording material is not in a transfer position is the same as that in a preceding sheet-passing period in which the recording material is in the transfer position; a current detecting member configured to detect a current flowing through the transfer member; and a controller configured to correct the voltage applied by the power source for the subsequent sheet-passing period on the basis of the detected current by the current detecting member in the non-sheet-passing period so that a predetermined current flows through the transfer member in the sheet-passing period.

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 stops the intermediate transfer belt so that a wrinkle is formed at a predetermined position of an intermediate transfer belt and, by detecting a reference mark during a preparation operation for forming an image when starting image formation, the toner image is not transferred onto the wrinkle formed in the intermediate transfer belt when formation of a toner image is started immediately after the preparation operation has been completed.

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: A toner pattern for detecting the degree of toner deterioration is created on a photosensitive element and transferred to an intermediate transfer belt by a primary transfer unit under a transfer condition different from that at the time of image formation. A toner adhesion amount detection unit detects the toner adhesion amount of the toner pattern at multiple places. A degree-of-toner-deterioration calculation unit calculates the degree of toner deterioration on the basis of the variation in data of the toner adhesion amount at multiple places detected by the toner adhesion amount detection unit. A background potential determination coefficient in a process control unit is controlled on the basis of the degree of toner deterioration calculated by the degree-of-toner-deterioration calculation unit.

Abstract: An image forming apparatus includes an image forming device, a print object moving device configured to move a print object in a moving direction relatively to the image forming device, a detector configured to detect images formed on the print object, and a control device configured to control the image forming device to form a first plurality of marks and a second plurality of marks on the print object. The first marks are along the moving direction and the second marks are along the moving direction and to be away from the first marks in a width direction that is perpendicular to the moving direction and the second marks are smaller in number than the first marks. The control device is further configured to control the detector to detect the first marks and the second marks on the print object for detecting deviation in image forming positions.

Abstract: An image forming apparatus includes a photosensitive drum, a charging section, an exposure section, a developing section, an ion-conductive transfer roller, a transfer bias applying section configured to apply a transfer bias of reverse polarity to charge of toner to the transfer roller, a conveyance section, and a control section. The control section is configured to, during double-sided printing, cause the transfer bias applying section to apply a reverse bias of the same polarity as the charge of the toner to the transfer roller while a recording medium is reversed and conveyed again to a toner image transfer position.

Abstract: An image forming apparatus includes: an image carrier; a toner image forming unit that forms a toner image on the image carrier; a transfer unit that transfers the toner image on the image carrier to a transfer target having ridges and valleys on a surface thereof; an adjusting unit that adjusts a ratio of A/B, where A is a transfer ratio [%] from the image carrier to a valley portion of the transfer target while B is a transfer ratio [%] from the image carrier to a ridge portion of the transfer target, based on an adjustment input by a user; and a control unit that controls a transfer condition of the transfer unit based on the ratio of A/B adjusted by the adjusting unit.

Abstract: An image forming apparatus including: an image bearing member for bearing a toner image; a transfer section, which is pressed against, and is separated from, the image bearing member, for transferring a toner image on the image bearing member onto a recording medium when being pressed against the image bearing member, a transfer section drive section for driving the transfer section to rotate; and a control section configured to control the transfer section drive section to carry out constant speed control and constant torque control, to drive said transfer section to rotate at a constant speed, and at a constant torque, respectively, wherein the control section carries out the constant torque control while the transfer section is pressed against the image bearing member, in accordance with a drive torque detected when the constant speed control is carried out while the transfer section is separated from the image bearing member.

Abstract: A system that avoids any stopping or reversing of the web direction in a continuous feed printer, instead maintaining consistent process speed, only requiring a slowing and speeding up of the web to cycle through the PR belt seam. This is done by forming a web loop and then immediately flattening the loop after passage of the seam through the transfer zone that includes two transfer BTR rolls with alternating transfer operations, but simultaneous transfer for short periods. Two vacuum assist rolls, one located between the two bias transfer rolls controls the formation of the web loop. A pair of nip forming rolls upstream of the first transfer station and a second vacuum assist roll downstream of the second transfer station control the size of the loop.

Abstract: An image processing apparatus includes an image forming unit, an adjustment unit, an image control unit, a sensor, a deviation amount calculating unit, and a determination unit. The image forming unit forms an image. The adjustment unit forms one set of a plurality of predetermined images in color, and adjusts color deviation. The image control unit controls the image forming unit to form a lesser number of predetermined images than the number of predetermined images formed by the adjustment unit. The sensor detects the predetermined images formed on the basis of control of the image control unit by the image forming unit. The deviation amount calculating unit calculates a deviation amount on the basis of the predetermined images. The determination unit determines whether or not color deviation occurs on the basis of the deviation amount, and controls performance of the adjustment unit on the basis of the determination result.

Abstract: An image forming apparatus includes a transfer bias output device and an information receiving device. The transfer bias output device outputs a transfer bias including a superimposed bias composed of an AC bias superimposed on a DC bias to form a transfer electric field in a transfer nip between an image bearing member bearing a toner image and a nip forming member, to transfer the toner image onto a recording medium in the transfer nip. A controller operatively connected to the information receiving device and the transfer bias output device causes the transfer bias output device to change a target output of a peak-to-peak voltage of the AC bias based on information received by the information receiving device that affects transfer of the toner image and to reduce a target output of the DC bias as the target output value of the peak-to-peak voltage of the AC bias increases.

Abstract: An image forming apparatus including; an image carrier carrying a toner image; a transfer belt making pressure contact with the image carrier through a sheet of paper and transferring the toner image onto the sheet of paper; a plurality of supporting rollers stretching and supporting the transfer belt; and a transfer roller to which transfer electrical current is applied, as well as making pressure contact of the transfer belt with the image carrier from a back surface of the transfer belt, wherein at least one roller of the supporting rollers is formed in an inverted crown shape with a size of the center portion is smaller than a size of the end portion, and the transfer belt is rotationally driven for a prescribed time without applying transfer electrical current both or in either of before and after transfer of a toner image.

Abstract: An image forming apparatus having: an image support that supports a toner image; a transfer member adapted to sandwich with the transfer member and the image support; a voltage application unit that applies a transfer bias voltage to the transfer member; a current detecting unit that detects transfer current flowing from the voltage application unit to the transfer material after transfer processing on the transfer material starts; and a control unit that sets an upper limit of transfer current on the basis of a value of the transfer current detected by the current detecting unit, and thereafter further acquires a transfer current value from the current detecting unit to control a transfer bias voltage generated by the voltage application unit, such that the transfer current value during transfer does not exceed the upper limit.

Abstract: An image forming apparatus includes an image bearer to bear a latent image formed thereon, a developing device to render visible the latent image borne on the image bearer as a toner image, and a transfer device to transfer the toner image onto a recording medium either directly or via an intermediate transfer member. A granularity detector is provided to detect granularity of the toner image transferred onto the recording medium. A controller is provided to control a transfer rate of toner in the toner image transferred onto the recording medium to reduce the image degradation when the granularity detected by the granularity detector exceeds a prescribed threshold.

Abstract: An image forming apparatus is disclosed that can reduce the time required for adjustment operations when a first adjustment operation that requires speed change and a second adjustment operation that does not require speed change overlap. When first adjustment operation that can be performed at a first speed is to be performed during operation at a second speed lower than the first speed, the image formation speed is changed from the second speed to the first speed. When second adjustment operation that can be performed at a plurality of image formation speeds is to be performed during operation at the second speed, the second adjustment operation is performed while maintaining the second speed. When both the first and second adjustment operations are to be performed during operation at the second speed, the image formation speed is changed from the second speed to the first speed.

Abstract: In an image forming apparatus, a transfer current output unit outputs a transfer current having a same value as a target value to a nip forming member to transfer a toner image on a latent image carrier to the nip forming member to determine the target value based on an algorithm representing a relationship between an image area ratio of the toner image and the target value and the image area ratio, and in an algorithm for a second transfer step in which the toner image is transferred to be superimposed on the toner image of the nip forming member to which the toner image has been transferred, a smaller target value is related to a same image area ratio compared to the algorithm for a first transfer step in which the toner image is transferred to the nip forming member to which no toner image is transferred.

Abstract: An image forming apparatus includes a paper cassette feeding a recording material, an image forming unit forming an image on a photosensitive member, a primary transfer roller transferring the image onto an intermediate transfer belt, a secondary transfer roller transferring the image onto the recording material, and a sensor detecting the size of the recording material. The timing of starting feeding the recording material is earlier than the timing of starting forming the image. When image formation on the recording material is started, until the sensor detects the size of the recording material, a plurality of images are formed on the intermediate transfer belt at a first interval according to a predetermined recording material size, and after the sensor detects the size of the recording material, a plurality of images are formed on the intermediate transfer belt at a second interval according to the detected recording material size.

Abstract: When a toner image formed on the surface of a photosensitive drum is transferred onto an intermediate transfer belt, a transfer bias is applied to a primary transfer portion. When a patch formed in an upstream image forming station and transferred onto the intermediate transfer belt and a patch formed on the surface of the photosensitive drum pass through the primary transfer portion, a passing bias different from the transfer bias is applied to the primary transfer portion. A control section controls a laser beam scanner as exposure member not to expose the surface of the photosensitive drum to which the passing bias is applied.

Abstract: An image forming apparatus includes: an image bearing member; a transfer portion; a first electrostatic cleaning portion including a first electroconductive member; a second electrostatic cleaning portion including a second electroconductive member; a first detecting portion for outputting first information corresponding to a first current passing through the first electroconductive member; a second detecting portion for outputting second information corresponding to a second current passing through the second electroconductive member; and a controller for controlling, based on the first information and the second information, a transfer voltage so that the voltage is decreased when a decrease amount of the first current is larger than that of the second current and so that the voltage is increased when the decrease amount of the second current is larger than that of the first current.

Abstract: An image forming apparatus includes a first detection portion at a first guide provided in an image forming unit and a second detection portion at a second guide provided in a unit drawable to the exterior of the image forming apparatus. Since there are many parts in this apparatus, an error in the relative positions of the first and the second detection portions is large. The image forming apparatus includes a lock member configured to lock the unit to an image forming apparatus main body, and a pressure member configured to, when the unit is locked to the image forming apparatus main body, press the first guide and the second guide to each other. As a result, adjustment of the relative positions of the first and the second detection portions is not required at the time of replacement of the unit or the detection portions.

Abstract: An image forming apparatus includes a belt member bearing a toner image, a contact member disposed inside loop formed by the belt member, a rotary pressing member to contact the contact member through the belt member and form a nip between the contact member and the rotary pressing member via the belt member through which a recording medium is conveyed, and a transfer device to transfer the toner image onto the recording medium. An amount of winding of the belt member around the rotary pressing member is changeable between a first state in which the belt member is wound around the rotary pressing member upstream from the nip in the direction of move to the nip and a second state in which the amount of winding of the belt member around the rotary pressing member is reduced from the first state while contacting the belt member.

Abstract: An image forming apparatus that reduces a time period during which no image is formed due to a margin in leading end portion, by calculating the margin in leading end portion from position information of an image and moving forward output timing of a /TOP signal according to the margin in leading end portion.

Abstract: In an image forming apparatus that separates a thin recording material by pushing up a transfer belt, if a position where a thick recording material separates from the transfer belt is far from a leading end of a recording-material guide, conveyability of the separated thick recording material after separation becomes stable. A stretching member is provided downstream of a push-up means and upstream of the recording-material guide in a recording-material conveying direction, and the stretching member separates a thick recording material from the transfer belt.

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: An image forming apparatus includes an image bearing member, a charger for electrically charging the member, an electrostatic latent image forming device for forming an electrostatic latent image on the member, a developer for developing the electrostatic latent image into a toner image, a transferer for transferring the toner image from the member onto a recording material and including a transfer member to which a transfer voltage is to be applied, a transfer-voltage source variably setting the transfer voltage, and a circuit for detecting a current passing between the image bearing and the transfer members by the transfer voltage applied from the voltage source, and a controller for controlling the voltage source. The controller sets the transfer-voltage value, applied from the voltage source during a non-passing period of the recording material, so that a predetermined current is detected by the circuit.

Abstract: Disclosed is a closed-loop control method and system to control the nip width and transfer field uniformity associated with an image marking apparatus. According to an exemplary embodiment, a closed-loop control system senses the uniformity of the image transfer field and applies forces to a transfer nip based on the sensed field to provide a more uniform field.

Abstract: An image forming apparatus including a latent image bearing member, a charger, a latent image forming device, a developing device, and a transfer device is provided. The transfer device is adapted to transfer a toner image formed on the latent image bearing member onto an intermediate transfer member or a recording medium by action of a transfer elected field in a transfer position where the latent image bearing member faces the transfer device. When a non-charged portion of the latent image bearing member that has not been charged to a predetermined potential by the charger passes through the transfer position, a strength of the transfer electric field is lowered than that in transferring the toner image.

Abstract: A voltage maintenance element is connected to a contact member that contacts a primary transfer surface area of an intermediate transfer belt to which toner images are transferred from a plurality of image carriers between stretch members, in such a way as to prevent the electric potential of the intermediate transfer belt from varying between respective stations.

Abstract: A printing system includes a rotatable transport member that transports a receiver on its obverse. A tackdown unit includes an electrode arranged facing the reverse of the transport member. A source responsive to the control system produces a tackdown current, and a charger spaced apart from the transport member facing the obverse thereof selectively deposits charge on the receiver in response to the tackdown current. A non-contact voltmeter arranged facing the receiver on the obverse after the charger measures a resulting voltage. A control system drives a selected voltage or current through the charger using the source and measures a resulting voltage using the non-contact voltmeter. The selected voltage or current and the measured resulting voltage are used to automatically estimate a capacitance of the receiver.

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: A secondary transfer facing roller includes a roller part that has a through-hole penetrating in a rotary shaft line direction at a rotation center position, and a penetrating shaft member penetrating the through-hole of the roller part and spinning the roller part on a surface of the penetrating shaft member. Eccentric cams are fixed to both end regions that are not located in the roller part, so as to rotate integrally with the penetrating shaft member. A position regulating cam and an abutting roller form a gap between the intermediate transfer belt and the secondary transfer roller immediately before a transfer sheet enters a transfer nip part. While the gap is formed, current flows between the intermediate transfer belt and the secondary transfer roller via the position regulating cam and the abutting roller.

Abstract: An image forming apparatus includes image carrier carrying latent image, developer carrier supplying developer on the image carrier, transfer part transferring the developer on the image carrier, cleaning blade removing attachment that attaches to a surface of the image carrier, internal environment detection part detecting an internal environmental temperature in the apparatus, developer disposal control part controlling disposal of developer from the developer carrier to the image carrier, and voltage control part controlling an applied voltage to the transfer part. Wherein, the developer disposal control part determines an absolute value of the applied voltage larger, which is applied to the transfer part during disposing the developer, where the internal environment temperature is high, and the voltage control part controls the applied voltage to the transfer part based on the absolute value of the voltage decided by the developer disposal control part.

Abstract: An image forming apparatus includes a transport member, image forming units (used as pattern forming unit), a pattern detector, and an image misalignment detector. The image forming units form correction-use patterns for each color on the transport member. The pattern detector directs a light beam onto the transport member having the correction-use patterns and detect reflected light reflecting from the transport member. The image misalignment detector detects image misalignment of the correction-use patterns. The pattern forming unit forms a reference color pattern and a first color pattern. The pattern detector uses an irradiation light having a first wavelength matched to a spectral sensitivity peak of the first color pattern to detect an intensity of reflected light reflected from the transport member. The image misalignment detector computes an image misalignment value between the reference and first color patterns based on the intensity of reflected light reflected from the transport member.

Abstract: A transfer device includes a transfer roller that has a characteristic in which an electrical resistance is changed in accordance with a rotation speed, contacts a transferred body that moves in synchronization with movement of an image holding body holding a toner image, and transfers the toner image held by the image holding body on the transferred body by applying a transfer voltage to the transferred body; and a regulator that regulates the rotation speed of the transfer roller independently from the movement of the image holding body and the transferred body.

Abstract: An image forming apparatus capable of improving the reliability of intermediate transfer belt shift control and attaining a high quality image. The image forming apparatus includes an intermediate transfer belt onto which a toner image is transferred and formed, a shift position detecting sensor that detects a shift position of the belt, a shift control roller that changes the shift position of the belt, and an angle adjustment cam and an angle adjustment arm that correct an inclination angle of the roller. An amount of correction for the inclination angle is calculated by an ASIC based on the belt shift position detected by the sensor. In a Kf multiplier and a Kr multiplier, coefficient values used for the calculation of the amount of correction for the inclination angle can variably be changed independently for respective directions of control for the roller inclination angle.

Abstract: An image forming apparatus includes a toner forced consumption control unit that performs toner forced consumption control in which toner in a developing unit is forcibly consumed when a certain condition to perform the toner forced consumption control is met. The certain condition to perform the toner forced consumption control includes a specific performance condition that a transfer bias switching condition to switch a transfer bias to a superimposed transfer bias in which an alternating current component is superimposed on a direct current component, from a direct current transfer bias is met. When the specific performance condition is met, the toner forced consumption control unit performs preliminary toner forced consumption control in which the toner forced consumption control is performed before an image forming operation using the superimposed transfer bias is started.

Abstract: An image forming apparatus is operable in a mode in which a speed of an intermediary transfer belt is changed after all of the toner images are primary-transferred onto the intermediary transfer belt, and the toner image primary-transferred on the intermediary transfer belt is passed through a secondary transfer position and primary transfer position in this order to reach the secondary transfer position, where the toner image is secondary transferred onto the transfer material, and a controller for making, before the image forming apparatus is operated in the mode to change the speed of the intermediary transfer belt, a potential difference between the intermediary transfer belt and the photosensitive member at the primary transfer position smaller than a potential difference between the intermediary transfer belt and the photosensitive member when the toner image is primary transferred from the photosensitive member onto the intermediary transfer belt.

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.

Abstract: An image forming apparatus includes a plurality of toner-image forming units that receive image data and form electrostatic latent images on image bearing members in accordance with the image data, and form toner images of respective colors by developing the electrostatic latent images, an intermediate transfer member onto which the toner images are transferred, a transfer unit that transfers the toner images of the respective colors onto the intermediate transfer member, a controller that performs transfer control for changing a transfer pressure applied when the transfer unit transfers the toner images onto the intermediate transfer member, and a misregistration detector that detects a difference of a transfer position of each of the toner images of the respective colors on the intermediate transfer member when the transfer control is performed by the controller.

Abstract: An image forming apparatus includes an image bearing member; a transfer member for transferring a toner image from the image bearing member onto a transfer material at a transfer portion; a control portion for controlling a voltage to be applied to the transfer member; a current detecting portion for detecting a value of a current passing through the transfer portion; a calculating portion for calculating a relationship between values of the voltage and the current obtained by applying voltages of different values at different intervals between adjacent images during execution of a continuous image forming mode in which the images are continuously formed on recording materials; a determining portion for determining the voltage value for a target current from the calculated relationship; and a switching portion for switching the voltage value to the voltage value determined by the determining portion during the execution of the continuous image forming mode.

Abstract: An electrostatic transfer control method that avoids undesired retransfer effects. A printing device develops and transfers several control patches. The patches are transferred at different electrostatic set points and a control strategy is utilized involving one or more density sensors to measure the transferred toner patches whereby the obtained density information can be used to compute the optimal value of electrostatic transfer bias. Print operators can adjust the bias value based on preferences for predetermined standards.