Abstract: An image forming apparatus includes a toner image bearer, a transfer device, a cleaner, a bias power source, and circuitry. The toner image bearer bears a toner image. The transfer device performs a transfer process The cleaner contacts the toner image bearer to remove transfer residual toner that is subject to the transfer process and remove untransferred toner that is not subject to the transfer process. The bias power source applies one of a first bias and a second bias different from the first bias to the cleaner. The circuitry controls the bias power source to output the first bias to the cleaner in response to a start of an image forming operation to remove the untransferred toner from the toner image bearer and control the bias power source to switch an output from the first bias to the second bias.

Abstract: A powder conveying device includes a drop conveyance passage, an intersecting conveyance passage, a conveying screw, and a floating member. Powder entering from an inflow port drops in the drop conveyance passage. The intersecting conveyance passage communicates with a lower end of the drop conveyance passage and extends in an intersecting direction that intersects the drop conveyance passage. The conveying screw is disposed in the intersecting conveyance passage and rotates in a specified direction to convey the powder in the intersecting direction. The floating member is movably installed in the drop conveyance passage and floats in the drop conveyance passage to move by contact with the conveying screw. The inflow port and the floating member interfere with each other to prevent the floating member from coming out of the inflow port of the drop conveyance passage.

Abstract: An image forming apparatus includes an image bearer; a nip forming member configured to form a transfer nip between the image bearer and the nip forming member; a nip pressure changer configured to change a nip pressure of the transfer nip; a transfer bias applier configured to apply, to the transfer nip, a transfer bias in which an AC component is superimposed on a DC component; and a DC component adjuster configured to adjust the DC component in the transfer bias, according to the nip pressure that is changed by the nip pressure changer.

Abstract: A transfer device includes a transfer roller and a transfer counter roller. The transfer roller has an elastic layer, contacts with and separates from an image bearer including a belt-shaped elastic body, and nips a recording medium with the image bearer. The transfer counter roller has an elastic layer, is disposed facing the transfer roller, and nips the image bearer with the transfer roller. The transfer counter roller or the transfer roller is applied with a bias to transfer the toner image. Each of the elastic layers of the transfer roller and the transfer counter roller has an Asker C hardness of 75 or less. A difference in thickness between the elastic layers of the transfer roller and the transfer counter roller is ±3% or less.

Abstract: A biasing force adjusting device includes a roller, a roller holder, a first biasing member, and a second biasing member. The roller faces a mover. The roller holder holds the roller and is displaceable with respect to the mover. The first biasing member applies a first biasing force to the roller holder to press the roller against the mover. The second biasing member applies a second biasing force greater than the first biasing force to the roller holder to press the roller against the mover.

Abstract: An image forming apparatus includes a rotatable image bearer, a transfer rotator, a detector, and circuitry. The image bearer bears an image. The transfer rotator transfers the image from the image bearer onto a recording medium sandwiched and conveyed between the image bearer and the transfer rotator. The detector detects length information indicating a length, in a direction of conveyance of the recording medium, of the image on the recording medium. The circuitry corrects a correction value, based on the length information detected by the detector and a target value of the length information, to correct an image magnification, in the direction of conveyance of the recording medium, of the image to be formed on the recording medium. The circuitry controls an image forming operation of forming the image on the recording medium with the correction value.

Abstract: An image forming apparatus includes an image bearer; a nip forming member configured to form a transfer nip between the image bearer and the nip forming member; a nip pressure changer configured to change a nip pressure of the transfer nip; a transfer bias applier configured to apply, to the transfer nip, a transfer bias in which an AC component is superimposed on a DC component; and a DC component adjuster configured to adjust the DC component in the transfer bias, according to the nip pressure that is changed by the nip pressure changer.

Abstract: An image forming apparatus includes an image bearer, a transfer rotator, an adjuster, and circuitry. The image bearer bears a toner image. The transfer rotator contacts the image bearer to form a transfer nip between the transfer rotator and the image bearer. The transfer rotator transfers the toner image from the image bearer onto a sheet conveyed to the transfer nip. The adjuster adjusts at least one of a relative difference in linear velocity of the transfer rotator to the image bearer at the transfer nip and a relative contact pressure of the transfer rotator to the image bearer at the transfer nip. Based on a difference in image magnification, in a direction of conveyance of the sheet, of toner images transferred onto surfaces of one or more sheets conveyed to the transfer nip, the circuitry causes the adjuster to reduce the difference in image magnification.

Abstract: An image forming apparatus includes a rotatable image bearer, a transfer rotator, a detector, and circuitry. The image bearer bears an image. The transfer rotator transfers the image from the image bearer onto a recording medium sandwiched and conveyed between the image bearer and the transfer rotator. The detector detects length information indicating a length, in a direction of conveyance of the recording medium, of the image on the recording medium. The circuitry corrects a correction value, based on the length information detected by the detector and a target value of the length information, to correct an image magnification, in the direction of conveyance of the recording medium, of the image to be formed on the recording medium. The circuitry controls an image forming operation of forming the image on the recording medium with the correction value.

Abstract: A roller unit includes a roller, an arm, a holder, a tension spring, and a restriction member. The arm rotatably holds the roller. The holder swingably holds the arm. The tension spring includes a first hook at one end of the tension spring and a second hook at another end of the tension spring. The first hook is hooked on an arm-side hook of the arm. The second hook is hooked on a holder-side hook of the holder. The restriction member is configured to restrict movement of the tension spring in a state in which the first hook or the second hook is unhooked.

Abstract: An image forming apparatus includes an image bearer, a transfer rotator, an adjuster, and circuitry. The image bearer bears a toner image. The transfer rotator contacts the image bearer to form a transfer nip between the transfer rotator and the image bearer. The transfer rotator transfers the toner image from the image bearer onto a sheet conveyed to the transfer nip. The adjuster adjusts at least one of a relative difference in linear velocity of the transfer rotator to the image bearer at the transfer nip and a relative contact pressure of the transfer rotator to the image bearer at the transfer nip. Based on a difference in image magnification, in a direction of conveyance of the sheet, of toner images transferred onto surfaces of one or more sheets conveyed to the transfer nip, the circuitry causes the adjuster to reduce the difference in image magnification.

Abstract: A belt running device includes a plurality of rollers, a belt, a guide, a regulating member, and an abutting member. The belt is wound around the plurality of rollers and configured to rotate. The guide is provided at an end of an inner peripheral surface of the belt. The regulating member is provided at an end of at least one roller of the plurality of rollers in the axial direction of the at least one roller and configured to contact the guide and regulate a movement of the belt in the axial direction of the at least one roller. The abutting member is configured to contact an outer peripheral surface of the belt to press the belt inward in a vicinity of a contact start point at which the guide and the regulating member start to contact when the belt runs.

Abstract: A roller unit includes a roller, an arm, a holder, a tension spring, and a restriction member. The arm rotatably holds the roller. The holder swingably holds the arm. The tension spring includes a first hook at one end of the tension spring and a second hook at another end of the tension spring. The first hook is hooked on an arm-side hook of the arm. The second hook is hooked on a holder-side hook of the holder. The restriction member is configured to restrict movement of the tension spring in a state in which the first hook or the second hook is unhooked.

Abstract: A belt running device includes a plurality of rollers, a belt, a guide, a regulating member, and an abutting member. The belt is wound around the plurality of rollers and configured to rotate. The guide is provided at an end of an inner peripheral surface of the belt. The regulating member is provided at an end of at least one roller of the plurality of rollers in the axial direction of the at least one roller and configured to contact the guide and regulate a movement of the belt in the axial direction of the at least one roller. The abutting member is configured to contact an outer peripheral surface of the belt to press the belt inward in a vicinity of a contact start point at which the guide and the regulating member start to contact when the belt runs.

Abstract: A belt device includes an endless belt, a support shaft, a contact member, a frame, and a regulating member. The contact member is configured to contact the belt. The support shaft is configured to support the contact member and rotate together with the contact member. The frame is configured to support the support shaft. The regulating member is configured to regulate movement of the contact member. The regulating member is configured to move relative to the frame, in a direction that crosses an axial direction of the support shaft, from a regulating position to regulate movement of the support shaft in an axial direction of the support shaft.

Abstract: An improved image forming apparatus includes an image bearer, a nip forming member, a transfer power source, and a controller. The controller switches a transfer mode between a first mode to transfer the toner image onto a first type sheet having a surface smoothness higher than a surface smoothness of a second type sheet and a second mode to transfer the toner image onto the second type sheet. The controller controls the transfer power source to output the transfer bias having an opposite-peak duty of greater than or equal to 50% that is a duty on the side of the opposite-peak value in the first mode. The controller controls the transfer power source to output the transfer bias having an opposite-peak duty of less than 50%, which is different from the opposite-peak duty of the first mode, in the second mode.

Abstract: An image forming apparatus includes a belt-shaped image bearer, a transferer, a guide, two rotators, and a support. The image bearer has an image bearing surface to bear an image thereon. The transferer forms a transfer section between the transferer and the image bearer, to transfer the image onto a recording medium. The guide is disposed upstream from the transfer section in a delivery direction of the recording medium, to guide the recording medium toward the transfer section. The two rotators are disposed upstream from the transfer section in a moving direction of the image bearer and in contact with a non-image bearing surface of the image bearer opposite to the image bearing surface, a first rotator being closer to the transfer section than a second rotator. The support supports the first rotator and the guide and adjusts a position of the first rotator and a position of the guide.

Abstract: An image forming apparatus includes an image bearer to bear a toner image, a nip forming member contacting the image bearer to form a transfer nip, and a transfer power source. The transfer bias has a transfer peak value to electrostatically move toner from the image bearer to the recording sheet and an opposite-peak value to electrostatically move less toner from the image bearer to the recording sheet than the transfer peak value. An opposite-peak duty of the transfer bias is less than 50%. The opposite-peak duty is tr/T×100% where T is one cycle of the transfer bias and tr is a time period during which the transfer bias is on a side of the opposite-peak value relative to an offset voltage of the transfer bias in the one cycle T.

Abstract: An image forming apparatus includes an image bearer, an intermediate transferor, a secondary transferor, a plurality of rotators including a secondary driving rotator, and a detector. The image bearer bears a detection image. The detection image is transferred from the image bearer to the intermediate transferor at a primary transfer position. The secondary transferor is looped around the plurality of rotators and disposed in contact with the intermediate transferor at a secondary transfer position where the detection image is transferred from the intermediate transferor to the secondary transferor. The secondary driving rotator drives the secondary transferor. The detector detects the detection image on the secondary transferor at a detection position. With this configuration, a distance from the secondary transfer position to the detection position on the secondary transferor is an integral multiple of a circumference of the secondary driving rotator.

Abstract: A belt device includes an endless belt, a support shaft, a contact member, and a regulating member. The support shaft supports the contact member. The contact member rotates together with the support shaft and contacts the belt. The regulating member moves between a regulating position to regulate movement of the support shaft and a releasing position to allow movement of the support shaft, thereby regulating movement of the contact member in an axial direction of the support shaft.