Abstract: An image forming apparatus includes an image bearing member, a transfer unit, a control circuit board, and a power supply module detachably attachable relative to the image forming apparatus. The image bearing member bears a toner image on a surface thereof. The transfer unit includes a transfer device to transfer the toner image onto a recording medium and is disposed opposite the image bearing member. The control circuit board controls the transfer unit. The power supply module is disposed in the transfer unit and includes a power source to apply, between the image bearing member and the transfer device, an AC-DC superimposed bias in which an alternating voltage (AC) is superimposed on a direct current (DC) voltage to form a transfer electric field to transfer the toner image from the image bearing member onto the recording medium.

Abstract: An image transfer device includes an image bearing member, a pair of opposed transfer members, a media separator, and an electrical bias applicator. The image bearing member defines an image bearing surface on which a toner image is created. The pair of opposed transfer members is disposed opposite each other via the image bearing member to form a transfer nip therebetween through which a recording medium is passed. One of the transfer members defines a first electrode to which a first electrical bias is applied. The media separator defines a second electrode downstream from the transfer nip to which a second electrical bias is applied. The electrical bias applicator includes a power supply connectable with each of the first and second electrodes to supply the first electrical bias to the first electrode and the second electrical bias to the second electrode.

Abstract: An image forming apparatus includes a transfer unit configured to transfer a toner image onto a recording medium; a power supply unit configured to output one of an alternating-current-based voltage including at least an alternating-current voltage and a direct-current voltage to the transfer unit; and a power supply control unit configured to cause the power supply unit to start switching to the alternating-current-based voltage a first time after the power supply unit stops outputting the direct-current voltage in the case that output of the power supply unit is switched to the alternating-current-based voltage, and cause the power supply unit to start switching to the direct-current voltage a second time after the power supply unit stops outputting the alternating-current-based voltage in the case that output of the power supply unit is switched to the direct-current voltage. The second time is longer than the first time.

Abstract: An image forming apparatus includes an image bearing member, an image forming unit for forming a toner image and a toner pattern comprising toner not to be transferred onto a recording medium for adjustment of a density of toner on a surface of the image bearing member, a nip forming member contacting the surface of the image bearing member to form a transfer nip therebetween, a transfer bias applicator for applying a transfer bias in which an alternating current component and a direct current component are superimposed to transfer the toner image onto the recording medium in the transfer nip, a first cleaning device to mechanically remove toner remaining on the image bearing member after passing through the transfer nip. The transfer bias applicator applies a charge eliminating bias to remove charge from toner in the toner pattern when the toner pattern passes through the transfer nip.

Abstract: An image forming apparatus includes an image bearing member, an image forming unit for forming a toner image and a toner pattern comprising toner not to be transferred onto a recording medium for adjustment of a density of toner on a surface of the image bearing member, a nip forming member contacting the surface of the image bearing member to form a transfer nip therebetween, a transfer bias applicator for applying a transfer bias in which an alternating current component and a direct current component are superimposed to transfer the toner image onto the recording medium in the transfer nip, a first cleaning device to mechanically remove toner remaining on the image bearing member after passing through the transfer nip. The transfer bias applicator applies a charge eliminating bias to remove charge from toner in the toner pattern when the toner pattern passes through the transfer nip.

Abstract: An image forming apparatus includes a controller and a transfer device including a power source to output a superimposed bias in which an AC voltage is superimposed on a DC voltage, a first electrode, a second electrode disposed opposite the first electrode with an image bearing member interposed therebetween to form a transfer electric field to transfer a toner image on the image bearing member to a recording medium. The controller including a CPU adjusts the transfer electric field and a transfer speed. One of the first electrode and the second electrode is connected to the power source, and the other is grounded. The controller adjusts the transfer speed such that in a case in which an oscillating electric field of the transfer electric field is strong, a maximum transfer speed is slower than the maximum transfer speed in a case in which the oscillating electric field is weak.

Abstract: An image transfer device includes an image bearing member, a pair of opposed transfer members, a media separator, and an electrical bias applicator. The image bearing member defines an image bearing surface on which a toner image is created. The pair of opposed transfer members is disposed opposite each other via the image bearing member to form a transfer nip therebetween through which a recording medium is passed. One of the transfer members defines a first electrode to which a first electrical bias is applied. The media separator defines a second electrode downstream from the transfer nip to which a second electrical bias is applied. The electrical bias applicator includes a power supply connectable with each of the first and second electrodes to supply the first electrical bias to the first electrode and the second electrical bias to the second electrode.

Abstract: An image forming apparatus includes an image bearing member, a transfer unit, a control circuit board, and a power supply module detachably attachable relative to the image forming apparatus. The image bearing member bears a toner image on a surface thereof. The transfer unit includes a transfer device to transfer the toner image onto a recording medium and is disposed opposite the image bearing member. The control circuit board controls the transfer unit. The power supply module is disposed in the transfer unit and includes a power source to apply, between the image bearing member and the transfer device, an AC-DC superimposed bias in which an alternating voltage (AC) is superimposed on a direct current (DC) voltage to form a transfer electric field to transfer the toner image from the image bearing member onto the recording medium.

Abstract: A transfer device including an image carrier; a transfer member disposed facing the image carrier; a transfer electrical field generator including a direct-current (DC) power source to generate a DC voltage and an alternating current (AC) power source to generate an AC voltage; and a controller. The transfer electrical field generator forms the transfer electrical field between the image carrier and the transfer member using the DC voltage and the AC voltage, to transfer the toner image on the image carrier, charged to a predetermined polarity, onto the recording medium. The controller controls the AC voltage source so that, the AC voltage output from the AC voltage source when a leading edge of the recording medium is positioned in the transfer electrical field is set larger than the AC voltage when the portion of the recording medium other than the leading edge is positioned in the transfer electrical field.

Abstract: An image forming apparatus includes a transfer device to transfer a toner image from an image bearing member onto a recording medium, disposed opposite the image bearing member, a transfer bias power source to apply, between the image bearing member and the transfer device, a superimposed transfer bias in which a direct current (DC) component and an alternative current (AC) component are superimposed to transfer the toner image borne on the image bearing member to the recording medium, and a controller to change the superimposed bias that the transfer bias power source applies. The controller changes the levels of the DC component and the AC component of the superimposed transfer bias in a color mode from that in a monochrome mode to secure a return electric field in the superimposed transfer bias by which the toner is returned from the recording medium to the image bearing member.

Abstract: An image forming apparatus includes a transfer unit configured to transfer a toner image onto a recording medium; a power supply unit configured to output one of an alternating-current-based voltage including at least an alternating-current voltage and a direct-current voltage to the transfer unit; and a power supply control unit configured to cause the power supply unit to start switching to the alternating-current-based voltage a first time after the power supply unit stops outputting the direct-current voltage in the case that output of the power supply unit is switched to the alternating-current-based voltage, and cause the power supply unit to start switching to the direct-current voltage a second time after the power supply unit stops outputting the alternating-current-based voltage in the case that output of the power supply unit is switched to the direct-current voltage. The second time is longer than the first time.

Abstract: An image forming apparatus includes a transfer unit configured to transfer a toner image onto a recording medium; a power supply unit configured to apply one of a superimposed voltage in which an alternating-current voltage and a first direct-current voltage are superimposed and a second direct-current voltage to the transfer unit; and a power supply control configured to, when the power supply unit outputs the superimposed voltage, instruct the power supply unit to output the first direct-current voltage at a first timing, and, when the power-supply unit outputs the second direct-current voltage, instruct the power-supply unit to output the second direct-current voltage at a second timing which is later than the first timing.

Abstract: An image forming apparatus includes an image bearing member to bear a toner image on a surface thereof, a transfer unit including a transfer device to transfer the toner image onto a recording medium, disposed opposite the image bearing member, a direct current (DC) power source to apply, between the image bearing member and the transfer device, a DC bias to form a first transfer electric field to transfer the toner image onto the recording medium, and a power supply module detachably attachable relative to the image forming apparatus. The power supply module includes an AC-DC superimposed bias power source to apply, between the image bearing member and the transfer device, a superimposed bias in which an alternating voltage is superimposed on a DC voltage to form a second transfer electric field to transfer the toner image onto the recording medium.

Abstract: An image forming apparatus includes an image carrier; a facing member facing the image carrier via a transfer position; a power supply to output a voltage between a first position on the image carrier side and a second position on the facing member side; a resistance detector to detect electrical resistance between the first position and the second position via the transfer position; and a controller to switch between a first transfer mode in which the power supply outputs a direct current voltage, and a second transfer mode in which the power supply outputs a superimposed voltage. When a toner image on the image carrier is transferred onto a recording medium at the transfer position, the controller selects either the first transfer mode or the second transfer mode. When the resistance detector detects the electrical resistance, the controller selects the first transfer mode.

Abstract: An image forming apparatus, includes an image bearer to bear a toner image; a transfer member to transfer the toner image; a transfer bias applicator to apply a transfer bias to the transfer member, the transfer bias applicator including a direct current voltage source to apply a direct current transfer bias constituted by a direct current voltage to the transfer member; and a superimposed voltage source to apply a superimposed transfer bias in which an alternating current voltage is superimposed on a direct current voltage to the transfer member; and a controller to switch between a direct current transfer mode during which the direct current transfer bias is applied to transfer the toner image and a superimposed transfer mode during which the superimposed transfer bias is applied to transfer the toner image while the direct current voltage source and the superimposed voltage source are off.

Abstract: An image forming apparatus includes an image bearing member, an image forming unit for forming a toner image and a toner pattern comprising toner not to be transferred onto a recording medium for adjustment of a density of toner on a surface of the image bearing member, a nip forming member contacting the surface of the image bearing member to form a transfer nip therebetween, a transfer bias applicator for applying a transfer bias in which an alternating current component and a direct current component are superimposed to transfer the toner image onto the recording medium in the transfer nip, a first cleaning device to mechanically remove toner remaining on the image bearing member after passing through the transfer nip. The transfer bias applicator applies a charge eliminating bias to remove charge from toner in the toner pattern when the toner pattern passes through the transfer nip.

Abstract: An image forming apparatus is provided, which forms a releasing agent absorption toner image on an in-between printed sides area of a moving surface of an image carrier in the duplex printing mode. When the in-between printed sides area of the moving surface enters a transfer position at which a toner image is transferred from the image carrier to a recording medium, the transferring operation of transferring the toner image from the image carrier to a recording medium is interrupted to keep the releasing agent absorption toner image on the in-between printed sides area of the moving surface of the image carrier.

Abstract: An image forming apparatus is provided, which forms a releasing agent absorption toner image on an in-between printed sides area of a moving surface of an image carrier in the duplex printing mode. When the in-between printed sides area of the moving surface enters a transfer position at which a toner image is transferred from the image carrier to a recording medium, the transferring operation of transferring the toner image from the image carrier to a recording medium is interrupted to keep the releasing agent absorption toner image on the in-between printed sides area of the moving surface of the image carrier.

Abstract: A cleaning device is used in an image forming apparatus to remove residual attachments including toner and paper powders from a surface of a movable intermediate transfer element onto which toner images are transferred from an image carrier. The cleaning device includes a cleaning brush that contacts the surface of the intermediate transfer element to apply a bias having a predetermined polarity to the toner adhered onto the surface of the intermediate transfer element so as to make uniform a polarity of the toner. The cleaning device further includes a pressing member that contacts the surface of the intermediate transfer element with a predetermined pressure. The pressing member is disposed at a position upstream of the cleaning brush in a direction of movement of the intermediate transfer element.

Abstract: A cleaning device is used in an image forming apparatus to remove residual attachments including toner and paper powders from a surface of a movable intermediate transfer element onto which toner images are transferred from an image carrier. The cleaning device includes a cleaning brush that contacts the surface of the intermediate transfer element to apply a bias having a predetermined polarity to the toner adhered onto the surface of the intermediate transfer element so as to make uniform a polarity of the toner. The cleaning device further includes a pressing member that contacts the surface of the intermediate transfer element with a predetermined pressure. The pressing member is disposed at a position upstream of the cleaning brush in a direction of movement of the intermediate transfer element.