Abstract: An image forming apparatus includes a first forming unit that forms a color image on a first image-carrier using a color toner, a first transfer unit that transfers the color image formed on the first image-carrier to a transfer medium at a first transfer bias, a second forming unit that, using an invisible toner absorbing infrared light or ultraviolet light, forms on a second image-carrier a code image representing information by an arrangement of dots, and a second transfer unit that transfers the code image formed on the second image-carrier to the transfer medium at a second transfer bias higher than the first transfer bias.

Abstract: An image forming apparatus includes: a carrier configured to carry developer; a voltage applying unit configured to apply a voltage to the carrier so that a carrier current flows from the voltage applying unit through the carrier; and a current detecting unit configured to detect the carrier current. The current detecting unit detects the carrier current at an uncharged portion of the carrier.

Abstract: An image forming apparatus includes at least one image carrier and a recording medium conveyor forming a transfer nip therebetween, a conveyance member disposed closest to the transfer nip on an upstream side of the transfer nip to convey the recording medium to the transfer nip, and a conveyance control mechanism to deactivate the conveyance member to stop providing a conveyance force to the recording medium after the leading edge of the recording medium has entered the transfer nip and before the trailing edge of the recording medium passes a point of force application and remaining in the inactive state until the recording medium passes the point of force application. The conveyance force remains unapplied to the recording medium from when the conveyance control mechanism deactivates the conveyance member to when the trailing edge of the recording medium passes the transfer nip.

Abstract: An image forming apparatus is constituted by an image bearing member; a corona charging member including a wire; a heat generating member for generating heat by energization; a shielding member, including the heat generating member, capable of shielding a portion of the corona charging member opposing to the image bearing member from the image bearing member by being moved between the corona charging member and the image bearing member; an energization control member for controlling energization of the heat generating member; and moving member for moving the shielding member to a first position at which the shielding member shields the portion and a second position retracted from the first position. When the shielding member is located at the first position, at least a part of the heat generating member is disposed between the corona charging member and the image bearing member.

Abstract: This disclosure is directed to systems and methods for calibrating, to a higher level of precision, the timing of operation of a bias transfer element in an image forming device. Specifically, the systems and methods are directed to calibrating the timing of forward and reverse biasing in a document processing apparatus to account for myriad mechanical and environmental disturbances.

Abstract: An image forming apparatus includes an image carrier, an intermediate transfer member, a primary transfer member, and a power supply unit to form a primary-transfer electric-field between the image carrier and the primary transfer member by performing constant-current control. The primary transfer member also detects a change in a primary transfer voltage in a sub-scanning direction that is applied to the primary transfer member from the power supply unit in the sub-scanning direction. There is a conductive member, a secondary transfer member, and a secondary-transfer electric-field forming member to apply a secondary transfer current to the secondary transfer member or the conductive member. A control device controls the secondary transfer current applied to the secondary transfer member or the conductive member in accordance with the change in the primary transfer voltage in the sub-scanning direction detected by the power supply unit.

Abstract: The image forming apparatus has a first and a second transfer member which transfer toner images onto a transfer body; and a control section, which measures a first density of a first toner image formed on the transfer body, measures a second density of a second toner image formed on the transfer body and determines a transfer current for the first and the second transfer member based on the first and the second density.

Abstract: An image forming apparatus includes an image carrier, a transfer unit, an applying unit, a detector, an acquisition unit, and an adjusting unit. The image carrier carries a toner image obtained by developing an electrostatic latent image using toner. The transfer unit transfers the toner image from the image carrier to a recording medium. The applying unit applies a voltage to the transfer unit. The detector detects a current being made to flow in the transfer unit. The acquisition unit acquires the image density of the toner image to be transferred in the transfer unit. The adjusting unit adjusts a voltage to be applied to the applying unit on the basis of a change in the relationship between the current detected by the detector and the image density acquired by the acquisition unit.

Abstract: According to one embodiment, a transfer device includes: a transfer member configured to come into contact with an image bearing member with a predetermined pressing force and transfer a toner image onto a sheet; a supporting member configured to support the transfer member; a regulating member configured to regulate a movement amount of the supporting member; a determining section configured to determine whether a sheet is present between the image bearing member and the transfer member; and a control section configured to control the regulating member to reduce a pressing force applied when the sheet is absent between the image bearing member and the transfer member to be smaller than a pressing force applied when the sheet is present between the image bearing member and the transfer member.

Abstract: An image forming device has a full-color image formation mode to form a color image using color photoconductor drums and a monochrome image formation mode to form a monochrome image using a photoconductor drum. In the image forming device, a driving unit drives rotation of an intermediate transfer belt or a transfer transport belt. A control unit changes rotational speeds of the color photoconductors in a transition from the full-color image formation mode to the monochrome image formation mode to make a torque to the driving unit in the full-color image formation mode equal to a torque to the driving unit in the monochrome image formation mode. A separator unit separates the color photoconductors from the intermediate transfer belt or the transfer transport belt after the rotational speeds of the color photoconductors are changed by the control unit.

Abstract: An image-forming device includes an image-bearing member, transfer unit, bias applying unit, a pair of conveying rollers, first sensor, second sensor, determining unit, and controller. An image is formed with developer on the image-bearing member. The transfer unit transfers the image formed on the image bearing member onto a sheet of paper at a transfer position located between the image-bearing member and the transfer unit. The bias applying unit applies a transfer bias to the transfer unit. The conveying rollers convey the sheet of paper to the transfer position. The first sensor detects an electrical property of the conveying rollers. The second sensor detects an electrical property of the transfer unit. The determining unit determines a bias for an ambient condition based on the detection results of the first sensor and the second sensor. The controller controls the bias applying unit to apply the bias to the bias applying unit.

Abstract: An image forming apparatus in which multiple image forming units for forming a developer image arranged along a prescribed medium feeding path are disposed in a manner to contact and face a belt component, the image forming apparatus includes an image formation driving unit for driving said multiple image forming units; a belt component driving unit for driving said belt component; and a drive control unit for supplying a drive command to said belt component driving unit and said image formation driving unit, said drive control unit sequentially initiating the driving of said image forming units from said image forming unit located downstream in the medium feeding path, after initiating the driving of said belt component drive unit.

Abstract: A color image forming apparatus includes one image bearing member, an image forming unit configured to successively form images with toners in plural different colors on the image bearing member per color, a revolving intermediate transfer member, and a transfer unit configured to successively transfer the images on the image bearing member onto the intermediate transfer member in a superimposed relation in a transfer section. Images are transferred in a superimposed relation by executing control such that, when formation of the next image is not started at a due timing of starting the formation of the next image, a timing at which transfer is started after the formation of the next image and a timing at which a leading end of the previously transferred image reaches the transfer section are matched with each other by temporarily changing the revolving speed of the intermediate transfer member or stopping it.

Abstract: An image forming apparatus is configured to control the timing to switch a development unit by a development rotary after forming an image, based on the size of the image to be formed. Accordingly, if the switching of the development unit is completed within a time period corresponding to a trailing edge margin of an image area, a subsequent color image can be formed without idling an intermediate transfer member, so that the image forming apparatus can suppress or reduce degradation of the throughput.

Abstract: In an image forming apparatus, a control portion forms a restoring toner image (restoring toner band) at a position, in which the refreshing toner image overlaps with a control image with respect to a longitudinal direction of a secondary transfer roller, during post-rotation after image formation in an image forming job is completed. The restoring toner band is formed in a length corresponding to 3 full circumferences of the secondary transfer roller for one-sheet image forming job, 2 full circumferences of the secondary transfer roller for 5-sheet image forming job, and one full circumference of the secondary transfer roller for 10-sheet image forming is job. In the case of an image forming job on 50 sheets or more, a lowering in cleaning performance of a secondary transfer member cleaning device for the secondary transfer roller is not caused to occur, so that the restoring toner band is not formed.

Abstract: At a time for resetting a transfer voltage after a predetermined time period from the performance of ATVC in both a color mode and a monochrome mode, ATVC is performed only in a currently running mode. A transfer voltage in another mode that the ATVC has not been performed at that time is set based on results of the ATVC performed in both the color and monochrome modes and a result of the ATVC performed in the other mode at that time.

Abstract: An image forming apparatus including a transfer unit that transfers onto a transfer medium an image that is formed on a photosensitive medium; a power supply unit that provides a transfer power to the transfer unit; and a transfer power control unit that controls the transfer power that is provided to the transfer unit by the power supply unit. The transfer power control unit sets as a target voltage an output voltage of the power supply unit that is measured by supplying an initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium and controls the power supply unit to apply the set target voltage to the transfer unit while an image is being transferred onto the transfer medium.

Abstract: In an image forming apparatus which transfers a toner image formed on a photoconductive member primarily onto the intermediate transfer belt and then transfers the same secondarily onto an image bearing medium, a relation; 40<F×R×L<1×104 (N?cm2), where F(N) is an average adhesion between the intermediate transfer belt and toner, R (?cm) is a resistivity, and L(cm) is a thickness of the intermediate transfer belt is satisfied.

Abstract: The image forming apparatus transfers a toner image onto a print paper via a transfer roller having an electrode configured to apply a bias electric potential upon the print paper. The image forming apparatus includes a humidity detection sensor to detect a humidity of the print paper, a retention electrode to preserve the toner image transferred to the print paper by applying a bias electric potential upon the print paper and a control device configured to control the bias electric potential of each of the electrode of the transfer roller and the retention electrode. The control device measures moisture content quantity of the print paper based on an interval from commencement of variation in the humidity to a maximum quantity of variation of the humidity and controls the bias electric potential of the electrode of the transfer roller and the retention electrode according to the moisture content quantity thus measured.

Abstract: An image forming apparatus including a latent image bearing member, a charger to evenly charge a surface of the latent image bearing member, an electrostatic latent image forming device to form an electrostatic latent image on the surface of the latent image bearing member, a developing device to develop the electrostatic latent image into a toner image using toner, a transfer bias application device to apply a transfer bias to an image transfer area where the latent image bearing member faces a recording medium, a pre-transfer neutralizing device to reduce an electric potential at a portion on the surface of the latent image bearing member, a surface electric potential detector to detect an electric potential at the surface of the latent image bearing member, and a radiation amount control device to control an amount of radiation from the pre-transfer neutralizing device.

Abstract: A method and system for compensating for an image quality defect in an image printing system comprising at least one marking station, the at least one marking station comprising a charging device for charging the image bearing surface, an exposing device for irradiating and discharging the image bearing surface to form a latent image, a developer unit for developing toner to the image bearing surface, and a transfer unit for transferring toner from the image bearing surface to an image accumulation surface is provided. The method includes sensing the image quality defect on an image bearing surface by an electrostatic voltmeter (ESV) in the image printing system and determining the frequency, amplitude, and/or phase of the image quality defect by a processor. In one embodiment, the method includes compensating for the image quality defect by modulating the power of an exposing device during an expose process.

Abstract: An electrographic image forming device may use a feedback loop to determine environmental conditions and accordingly set one or more operating parameters. The device may detect a resistance/capacitance characteristic of a feedback loop comprising an interface between a first component and a second component of an image forming unit. The device may detect temperature measurements and humidity measurements that can be used to calculate wet-bulb temperature or other metrics used to characterize ambient environmental conditions. The interface may be one in which a toner image is transferred during image forming device operation. A controller may adjust the resistance/capacitance characteristic in response to wet-bulb temperature in conjunction with measured transfer feedback voltage.

Abstract: An image formation apparatus includes an image carrier; a driving source generating a driving force for the image carrier; a drive transmission unit; a driving control unit controlling the driving source; an image formation unit forming an image on a surface of the image carrier; a transfer nip between a transfer member and the surface of the image carrier; a driving-force exerting unit exerting a driving force on any one of the image carrier and a first drive transmission member on a drive transmission path, and a specific drive transmission member imparting weakest spring characteristics among drive transmission members to a drive transmission system; a detecting unit detecting an estimation parameter used in estimating a driving-load-torque variation amount of the image carrier; a torque-variation-amount estimation unit; and a driving-force control unit controlling the driving force to cancel the driving-load-torque variation.

Abstract: An image forming apparatus equipped with an image forming unit capable of image formation using color toner and transparent toner includes, a determining unit to determine whether each pixel of image data belongs to an image region or a text region; a control unit to control the image forming unit by switching between transfer of a toner image to the image region and transfer of a toner image to the text region; a fixing unit to fix the toner image formed on recording material; and a transport unit to discharge the recording material on which the toner image is fixed or re-feed the recording material to the image forming unit.

Abstract: A transfer device includes: a first transfer unit that transfers a developer image formed on an image carrier to an intermediate transfer member; a second transfer unit that transfers the developer image on the intermediate transfer member to a recording medium; and a control unit that controls at least one of a transfer pressure and a transfer electric field by the first transfer unit in accordance with a type of the recording medium to which the developer image is transferred.

Abstract: An image forming apparatus includes an intermediary transfer member having an elastic layer; a toner image forming portion for forming a toner image for an image to be carried on the intermediary transfer member; a transfer member, which presses the intermediary transfer member, for transferring the toner image for the image from the intermediary transfer member onto a recording material; a pressing mechanism capable of changing pressure applied from the transfer member to the intermediary transfer member; and a controller for controlling the toner image forming portion so that a length of the toner image for the image on the intermediary transfer member with respect to a rotational direction of the intermediary transfer member is decreased with an increase of the pressure.

Abstract: In the case where a peripheral velocity of photosensitive drums differs from a peripheral velocity of an intermediate transfer belt, the peripheral velocity of the intermediate transfer belt or the peripheral velocity of the photosensitive drums is corrected. The velocity of the intermediate transfer belt is transiently varied in an image forming operation. Accordingly, a plurality of tonner patch patterns including toner patches are formed on the intermediate transfer belt, and the difference in peripheral velocity between the intermediate transfer belt and the photosensitive drums is estimated based on a difference between the displacements in the tonner patch patterns.

Abstract: An image forming apparatus includes an image bearing member; a stretched rotatable belt member; a transfer device for forming a transfer portion where a toner image is transferred from the image bearing member onto a recording material carried and conveyed on the belt member; a separation roller capable of separating the recording material from the belt member; a push-up device capable of pushing up a belt surface locally with respect to a widthwise direction of the belt member to separate the recording material from the belt member; and an execution portion for executing, when an abnormality occurs during an image forming operation, an operation in a stop mode in which the belt member is, after the image forming operation is stopped, rotated in a push-up state of the push-up device and then the rotation of the belt member is stopped.

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 image forming apparatus, image adjustment is performed by detecting a toner image constituting an image adjustment pattern 22 transferred to an intermediate transfer member. On the intermediate transfer member 2, a leading pattern 21 longer than a circumference of a secondary transfer roller 13 is formed at a leading position in a travelling direction of the intermediate-transfer-member ahead of the image adjustment pattern 22 by using a toner that is highest in brightness among toners used for the image adjustment pattern 22 or a toner that is higher in brightness than any toner used for the image adjustment pattern 22. Staining of the rear face of the recording medium due to toner adhering to the secondary transfer roller is prevented without increasing the apparatus scale.

Abstract: A printing apparatus includes a detection unit which detects a rotation period of a transfer belt, and a printing control unit which performs a printing preparation operation, and detects the rotation period if the printing preparation operation is started, and performs printing in the detected rotation period if the printing preparation operation is completed. Accordingly, a rotation period of the transfer belt is detected while performing the printing preparation operation, so that an initial printing time can be reduced.

Abstract: An intermediate transfer tandem type image forming device which has multiple first stage transfer units set parallel and a single power unit which simultaneously applies bias to the multiple first stage transfer units. When executing successive printing or both-sides printing and there is a need to change the bias value of the first stage transfer bias due to a mix of multiple types of recording media, the device is able to hold down electricity consumption, sustain image quality, and form images productively. When executing successive printing or both-sides printing, the application timing of the changed transfer bias due to the detection of a different recording medium to that of the initial medium is placed after the previous first stage transfer of a final color toner image is completed.

Abstract: An image forming apparatus including a transfer section for transferring a toner image formed on an image bearing member onto a sheet by pressure contact of the sheet against the image bearing member with a transfer member; a cleaning section having a cleaning blade to remove residual toner on the image bearing member; and a control section for controlling a rotation of the image bearing member so as to carry out a return action of a blade configuration which stops or reverses the rotation of the image bearing member, when the rotation amount reaches a predetermined value, wherein the control section additionally carries out the return action when the rotation amount reaches a value smaller than the predetermined value, in a case where a size of a sheet in a current job is larger than a size a sheet having been passed through in a previous job.

Abstract: A transfer device includes: a transfer section for transferring a toner image on an image carrier onto a sheet passing through a nip portion which is formed between the transfer section and the image carrier; an application section for applying a voltage to the transfer section; and a control section for controlling the application section, wherein the control section controls the application section to apply a voltage having an opposite polarity to a transfer polarity to the transfer section since a leading edge of the sheet in a conveyance direction advances into the nip portion until a predetermined non image area of the sheet has passed through the nip portion, and then switch to apply a voltage having the transfer polarity from the voltage having the opposite polarity to the transfer section while a non image area of the sheet passes through the nip portion.

Abstract: An image forming apparatus includes a plurality of image bearing members; an electrostatic image forming portion; a belt member; an electrostatic image transfer member for transferring an electrostatic index image, onto an electrostatic image transfer area located adjacent to an image area of a toner image with respect to a widthwise direction of the belt member, formed on the upstreammost image bearing member with respect to a rotational direction of the belt member; an antenna potential sensor for detecting an induced current of the electrostatic index image; a controller for controlling superposition of the toner images through detection of the electrostatic index image; and a setting portion on the basis of a detection result of the electrostatic index image which is formed during non image formation.

Abstract: An image forming apparatus including an image carrier; a transfer member, which is provided in a face-to-face relation to the image carrier and to which a transfer bias is applied; a first sensor that measures a resistance value of a section between the image carrier and the transfer member; and transfer bias controlling means. The transfer bias controlling means controls the transfer bias, which is applied to the transfer member based on a first resistance value measured by the first sensor before a recording sheet enters a nip between the image carrier and the transfer member and also based on a second resistance value measured by the first sensor when the recording sheet has entered the nip between the image carrier and the transfer member.

Abstract: An image forming apparatus includes an image carrier for carrying developer image, a transfer device configured to transfer the developer image to a recording media, a forward bias applying circuit configured to apply a forward bias voltage to the transfer device, and a reverse bias applying circuit configured to apply a reverse bias voltage to the transfer device. The apparatus includes a detecting circuit configured to detect inflow current flowing from the image carrier into the forward bias applying circuit, and a decision circuit configured to determine a lower limit of the reverse bias voltage based on a detected value of the inflow current when the detected value of the inflow current exceeds a first predetermined value. The reverse bias applying circuit applies the reverse bias voltage of the determined lower limit to the transfer device at least before the forward bias voltage is applied to the transfer device.

Abstract: An image forming apparatus includes a belt member, a toner image forming device, a stretching member for stretching the belt member, and a transfer member for transferring a toner image onto a recording material. The image forming apparatus also includes a fur brush for electrostatically cleaning the transfer member, a controller for controlling an electric field formed between the transfer member and the stretching member, and an executing portion for executing an ejecting operation for forming a second toner image in the form of a band which is not transferred onto the recording material. When the executing portion executes the ejecting operation, and the second toner image passes through the transfer portion, the controller forms an electric field having an absolute value which is smaller than an electric field for transferring the first toner image onto the recording material, and the fur brush electrostatically cleans said transfer member.

Abstract: An image forming apparatus includes an intermediate transfer belt unit and a transfer belt unit each of which has a deviation control mechanism and which are held in contact with each other at a transfer portion, wherein at least a steering roller on which a secondary transfer belt is suspended is situated such that a traction surface thereof does not constitute a transfer surface including a transfer roller.

Abstract: An image forming apparatus includes an intermediate transfer belt, a photosensitive belt, a primary transfer roller, a secondary-transfer opposing roller, and a secondary transfer roller. The photosensitive belt comes into contact with a surface of the intermediate transfer belt to form a primary transfer nip. The secondary-transfer opposing roller comes into contact with the surface of the intermediate transfer belt to form a secondary transfer nip. The closest distance between a surface of the photosensitive belt and that of the primary transfer roller is greater than the thickness of the intermediate transfer belt. A toner image on the intermediate transfer belt is transferred onto a recording sheet at the secondary transfer nip while a transfer bias is applied to the secondary transfer roller.

Abstract: An image forming apparatus includes an image carrier, an endless intermediate transfer member having a transport surface and being tensioned to transport a developer image, transferred from the image carrier to the intermediate transfer member, from a first transfer position to a second transfer position, a first transfer member that brings the intermediate transfer member in contact with the image carrier and transfers a developer image present on the image carrier to the intermediate transfer member at the first transfer position, a second transfer member that transfers the developer image to a recording medium at the second transfer position, a position adjusting member that adjusts a position of the transport surface of the intermediate transfer member downstream of the first transfer position, and a controller that controls the position adjusting member responsively to a type of the recoding medium to which the second transfer member transfers the developer image.

Abstract: An image forming apparatus includes an image bearing member; a transfer portion that transfers a toner image; a conveying member that conveys a recording material; a conveying member position index sensing member that senses a conveying member position index fixed to the conveying member in the transfer portion; a toner image position index sensing member that senses a toner image position index fixed to the image bearing member in the transfer portion; a drive member that can control a position of the conveying member in a moving direction of the conveying member and a rotating speed of the conveying member; and a control portion that controls the drive member to position the conveying member position index with respect to the toner image position index reaching the transfer portion based on the sensing results of the conveying member position index and the toner image position index.

Abstract: An image forming apparatus includes a bias controller that controls a first application unit that applies a bias to a transfer member. The bias controller applies a reverse bias to the transfer member when a first region passes through a nip part. Then, when a second region passes through the nip part, the bias controller applies a fixed first forward bias to the transfer member. When a third region passes through the nip part, in order to implement the control the bias controller applies a variable second forward bias to the transfer member. The first forward bias is set at a predetermined value or above and increases a potential of the transfer member 46 to a level at which a toner image is transferred in the second region when the second region passes through the nip part.

Abstract: An image forming apparatus includes a rotatable image bearing member on which a toner image is to be formed; a transferring device for transferring the toner image onto a transfer material at a transfer position; a separating member, disposed downstream of the transfer position with respect to a rotational direction of the image bearing member so as to contact the image bearing member, for separating the transfer material from the image bearing member; a density detecting device, disposed downstream of the transfer position with respect to the rotational direction of the image bearing member, for detecting a density of an image for density detection formed on the image bearing member; and an air moving device for moving air in the image forming apparatus in a direction of a rotation shaft of the image bearing member; wherein the density detecting device is disposed upstream of the separating member with respect to a direction of air movement by the air moving device.

Abstract: Printers are provided for printing using large particle toner. One printer has a printer controller causing a first imaging module to form first toner image using a first toner particle having a first charge-to-mass ratio and a median volume weighted diameter between 3 um and 9 um and having a first charge-to-mass ratio and, a second imaging module to form a second toner image using second toner particles having a median volume weighted diameter that is greater than 20 um and a charge-to-mass ratio that is between ? to ½ of the first charge to mass ratio of the first toner times the ratio of the median volume weighted diameter of the first toner to the median volume weighted diameter of the second toner. The first toner image is transferred to a receiver using a first electrostatic field and the second toner image is transferred using a second electrostatic field.

Abstract: An image forming apparatus includes a transfer roller that can be separated from an intermediate transfer belt. When an operational mode is switched from a multicolor mode to a mono-color mode, the image forming apparatus changes a rotational speed of the intermediate transfer belt to a level slower than a rotational speed of the intermediate transfer belt to be set in the multicolor mode to transfer a toner image to the intermediate transfer belt, then separates a first transfer member from the intermediate transfer belt, and after the first transfer member is separated from the intermediate transfer belt, the image forming apparatus increases the rotational speed of the intermediate transfer belt to a rotational speed to be set in the mono-color mode to transfer the toner image to the intermediate transfer belt.

Abstract: The present invention is directed to realizing a suitable electrical setting of a transferring unit as well as calculating the setting earlier than a conventional method. To achieve this, an image forming apparatus performs forcible light emission at an activation of a laser beam and automatic transferring voltage control (ATVC) concurrently. Then the image forming apparatus further corrects a result obtained by the ATVC during the forcible light emission and performs suitable electrical setting of a transferring unit.

Abstract: An image forming device is disclosed that is able to enlarge a gap of a nipping portion with a simple and inexpensive structure, and able to reduce impact when a front end of a recording sheet runs into or a back end of the recording sheet passes through the nipping portion. The image forming device includes an image carrying unit, an image forming unit, a transfer unit, a conveyance unit, a determination unit that determines whether a thickness of the recording sheet is greater than a threshold value, and a cam member that rotates to enlarge or reduce the gap of the nipping portion between the image carrying unit and the transfer unit according to rotational positions of the cam member. When the thickness of the recording sheet is greater than the threshold, the cam member rotates so that the gap of the nipping portion is enlarged.

Abstract: At a time for resetting a transfer voltage after a predetermined time period from the performance of ATVC in both a color mode and a monochrome mode, ATVC is performed only in a currently running mode. A transfer voltage in another mode that the ATVC has not been performed at that time is set based on results of the ATVC performed in both the color and monochrome modes and a result of the ATVC performed in the other mode at that time.

Abstract: An image forming apparatus and a control method thereof to improve quality of an image in consideration of a change in posture of a print media. The image forming apparatus can include a transferred unit on which a visible image is formed, a transferring unit to form a transfer region through which the visible image is transferred onto a print medium, along with the transferred unit, a bias supplying unit to supply bias to the transferring unit so that a transfer electric field is produced in the transfer region, and a controller to control the bias supplying unit to supply different first to third biases to the transferring unit while at least first to third regions of the print medium pass through the transfer region, respectively.