Abstract: In an image forming apparatus, a moving member is provided with a first engagement member. A lever is provided with a second engagement member to engage and disengage the first engagement member provided in the moving member. The lever moves between a predetermined first position and a second position different from the first position to move the moving member in such a manner that when the lever is at the first position, a transfer member reaches a contact position at which the transfer member is pressed against an image carrier via a belt, and when the lever is at the second position, the transfer member reaches a separation position at which the transfer member separates from the image carrier.

Abstract: An image forming apparatus includes a toner image carrying member, an image transfer device, a fixing device, a registration unit, a guide member, an upstream-side transportation unit, and a downstream-side transportation unit. The image transfer device transfers a toner image from the toner image carrying member to a recording medium. The fixing device fixes the toner image. The registration unit transports the recording medium. The guide member guides the recording medium. The upstream-side transportation unit includes an upstream-side transportation member, disposed at an upstream side in the transport direction of the recording medium. The downstream-side transportation unit includes the downstream-side transportation member, disposed at a downstream side in the transport direction of the recording medium. The upstream-side transportation unit includes an upstream-side positioning member to position the guide member to the upstream-side transportation member.

Abstract: An optical sensor detects at least one of a toner image and a toner adhesion amount per unit area based on a change of an optical characteristic on a surface of an endless belt member. A control unit performs a predetermined process based on a detection result obtained by the optical sensor. A sensor moving unit moves the optical sensor between a first position in opposite to a belt supporting area in which the endless belt member is supported by a supporting roller and a second position that is different from the first position. The detection result is obtained by the optical sensor when the optical sensor is placed at the first position by the sensor moving unit.

Abstract: A transfer unit includes a belt member, a bending roller, a transfer section, and a bias application unit. The belt member is extended between rollers and has a movable surface on which a toner image is transferred from an image carrier. The bending roller externally contacts the surface of the belt member to bend the belt member and rotates in conjunction with the belt member. The transfer section includes one of the rollers and a surface moving member. The surface moving member rotates at least one full turn while cleaning is performed on the surface moving member and the bending roller. A surface moving speed of the bending roller is equal to or greater than a surface moving speed of the surface moving member. A circumferential length L1 of the surface moving member and a circumferential length L2 of the bending roller satisfy L1?L2.

Abstract: A turnable transfer unit, including a transfer member forming a transfer nip while contacting an image bearer installed in an image forming apparatus; and a pressurizer pressurizing the transfer member to the image bearer, wherein the turnable transfer unit further includes a turnable lever member, including an engaging part engaging with a positioning part of the image forming apparatus; and a contact part contacting an opening and closing body openable and closable in the image forming apparatus, wherein the lever member turns in conjunction with a closing operation of the opening and closing body to position the transfer unit in the image forming apparatus.

Abstract: A powder container includes a first container to contain powder falling from an opening located in an upper portion of the powder container, a second container that contains the powder and is located in the first container, on a route through which the powder that falls from the opening, a powder transport mechanism to transport the powder from the first container to the second container, and a detection mechanism to detect whether or not the first container is completely or nearly filled with the powder based on a load to the powder transport mechanism.

Abstract: A transfer device, which transfers an image onto a recording medium directly or indirectly and is included in an image forming apparatus, includes an endless belt member extended between a drive roller rotated and a driven roller and configured to receive the image from the image carrier part onto either a surface thereof or the recording medium carried on the surface thereof while moving according to rotations of the drive roller, and a rotation speed detector configured to detect a rotation speed of the driven roller. An image detector is provided either to the transfer device or to the image forming apparatus to detect the image formed on the endless belt member directly or the recording medium carried on the endless belt member, and disposed facing the driven roller in a circumferential direction of the endless belt member.

Abstract: A cleaning apparatus is for removing a toner from a surface of an endless belt. The cleaning apparatus includes a blade, a blade holding structure, and an abutment maintaining structure. The blade abuts on the endless belt that is supported on a tension roller. The blade holding structure holds the blade with its rotation restricted, in a movable manner in the direction of motion adjustment to adjust tension on the endless belt, and causes the blade to abut on a winding area of the endless belt with respect to the tension roller. The abutment maintaining structure allows the blade to follow up movement of the tension roller to thereby maintain abutment of the blade on the endless belt.

Abstract: A cleaning apparatus is for removing a toner from a surface of an endless belt. The cleaning apparatus includes a blade, a blade holding structure, and an abutment maintaining structure. The blade abuts on the endless belt that is supported on a tension roller. The blade holding structure holds the blade with its rotation restricted, in a movable manner in the direction of motion adjustment to adjust tension on the endless belt, and causes the blade to abut on a winding area of the endless belt with respect to the tension roller. The abutment maintaining structure allows the blade to follow up movement of the tension roller to thereby maintain abutment of the blade on the endless belt.

Abstract: An optical sensor detects at least one of a toner image and a toner adhesion amount per unit area based on a change of an optical characteristic on a surface of an endless belt member. A control unit performs a predetermined process based on a detection result obtained by the optical sensor. A sensor moving unit moves the optical sensor between a first position in opposite to a belt supporting area in which the endless belt member is supported by a supporting roller and a second position that is different from the first position. The detection result is obtained by the optical sensor when the optical sensor is placed at the first position by the sensor moving unit.

Abstract: A plurality of supporting rollers over which the endless belt member is supported includes at least a driving roller that drives the endless belt member and a driven roller that is driven by a rotation of the endless belt member. A detecting unit detects a plurality of marks provided on the driven roller at a predetermined position. A control unit controls a speed at which a driving unit drives the endless belt member based on a result of detecting the marks. The driven roller functions as a tension roller that applies a tension to the endless belt member. The detecting unit is held by the tension 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 roller 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: A belt member faces a plurality of carrying bodies that respectively carry toner images or developers. A plurality of facing members respectively faces the carrying bodies via the belt member. A detaching unit brings at least one of the facing members to face a corresponding carrying body and detaches other facing members from other carrying bodies. A contacting member contacts the belt member to detach the belt member from the other carrying bodies when the detaching unit detaches the other facing members from the other carrying bodies.

Abstract: An endless belt device includes an endless belt and a plurality of rotary members rotatably supporting the endless belt. One of the plurality of rotary members includes a marker formed on a part of a circumferential surface of a rotation axis thereof. A reflection-type sensor is arranged to oppose the circumferential surface of the rotation axis of the one of the plurality of rotary members to detect the marker formed on the circumferential surface. A rotation speed of the endless belt is detected by detecting the marker on the circumferential surface of the rotation axis of the one of the plurality of rotary members by the reflection-type sensor.

Abstract: An image forming apparatus that transfers a toner image on a photosensitive element to a recording medium includes a transfer unit that includes a transfer member in a form of an endless belt pressed against an outer surface of the photosensitive element, and that is detachable from a main unit of the image forming apparatus; a first cleaning unit that cleans residual toner on the transfer member; and a waste toner receptacle that collects the residual toner cleaned by the first cleaning unit. The waste toner receptacle is arranged in an inner circumference of the transfer member. The waste toner receptacle is held inside the main unit, so that the transfer unit is detachable from the main unit.

Abstract: An endless belt device includes an endless belt and a plurality of rotary members rotatably supporting the endless belt. One of the plurality of rotary members includes a marker formed on a part of a circumferential surface of a rotation axis thereof. A reflection-type sensor is arranged to oppose the circumferential surface of the rotation axis of the one of the plurality of rotary members to detect the marker formed on the circumferential surface. A rotation speed of the endless belt is detected by detecting the marker on the circumferential surface of the rotation axis of the one of the plurality of rotary members by the reflection-type sensor.

Abstract: An image forming apparatus that transfers a toner image on a photosensitive element to a recording medium includes a transfer unit that includes a transfer member in a form of an endless belt pressed against an outer surface of the photosensitive element, and that is detachable from a main unit of the image forming apparatus; a first cleaning unit that cleans residual toner on the transfer member; and a waste toner receptacle that collects the residual toner cleaned by the first cleaning unit. The waste toner receptacle is arranged in an inner circumference of the transfer member. The waste toner receptacle is held inside the main unit, so that the transfer unit is detachable from the main unit.

Abstract: A cleaning apparatus is for removing a toner from a surface of an endless belt. The cleaning apparatus includes a blade, a blade holding structure, and an abutment maintaining structure. The blade abuts on the endless belt that is supported on a tension roller. The blade holding structure holds the blade with its rotation restricted, in a movable manner in the direction of motion adjustment to adjust tension on the endless belt, and causes the blade to abut on a winding area of the endless belt with respect to the tension roller. The abutment maintaining structure allows the blade to follow up movement of the tension roller to thereby maintain abutment of the blade on the endless belt.

Abstract: A fixing device includes a fixing belt, a first heater, a second heater, a supporting roller, and a counter roller. During activation of the fixing device, a maximum power is supplied to the first heater, and only the first heater heats the fixing belt. When a temperature on the fixing belt reaches a first reference temperature, the fixing belt is driven rotationally, the power supplied to the first heater is dropped, and power is supplied also to the second heater. When the temperature on the fixing belt reaches a target temperature and the temperature on the counter roller reaches a second reference temperature, fixing operation is allowed to start.

Abstract: A fixing device includes a fixing belt, a first heater, a second heater, a supporting roller, and a counter roller. During activation of the fixing device, a maximum power is supplied to the first heater, and only the first heater heats the fixing belt. When a temperature on the fixing belt reaches a first reference temperature, the fixing belt is driven rotationally, the power supplied to the first heater is dropped, and power is supplied also to the second heater. When the temperature on the fixing belt reaches a target temperature and the temperature on the counter roller reaches a second reference temperature, fixing operation is allowed to start.