Abstract: Disclosed is an image forming apparatus including a detachable unit having a rotator with a driven shaft coupling and a drive unit having a drive shaft coupling to engage with the driven shaft coupling and providing a force to the rotator via the drive shaft coupling. The driven shaft coupling includes spiral first and second receiving surfaces. The drive side shaft coupling includes a spiral first transmitting surface, which contacts the first receiving surface and provides a rotational force in a first rotational direction to the driven shaft coupling, and a spiral second transmitting surface, which contacts the second receiving surface and provides a force in the second rotational direction opposite to the first rotational direction to the driven shaft coupling when the drive shaft coupling rotates in the second rotating direction. The second transmitting and receiving surfaces are rougher than the first transmitting and receiving surfaces.

Abstract: An image forming apparatus includes a support frame, a driving device including a first supporting portion configured to hold the drive source on a first surface and configured to rotatably support the drive gear on a second surface, and a second supporting portion configured to support the drive gear with the first supporting portion, a board holding member disposed in a manner overlapping the first supporting portion in a rotational axis direction of the drive gear, and a third supporting portion disposed between the first supporting portion and the board holding member in the rotational axis direction, and configured to support the board holding member, one end of the third supporting portion being fixed to a side of the first surface of the first supporting portion by a first fastening member, another end of the third supporting portion being fixed to the board holding member by a second fastening member.

Abstract: An Oldham coupling having play in a rotational direction and being capable of transmitting a driving force. The Oldham coupling includes a developing drive gear as a first hub, a drive coupling as a second hub, and an intermediate member that transmits a driving force between the developing drive gear and the drive coupling. The developing drive gear includes a protruded portion that is fitted to a recessed portion of the intermediate member to transmit a driving force between the developing drive gear and the intermediate member. When seen in a rotational axis direction of the Oldham coupling, the shape of a protruded portion is a substantially rhombic shape.

Abstract: An image forming apparatus includes a driving unit including a driving source, a drive gear, a first support member that holds the driving source and includes a first support portion that supports one end portion of a rotation shaft of the drive gear, and a second support member that includes a second support portion that supports another end portion of the rotating shaft. The first support member includes a fastening hole disposed in a projection plane obtained by projecting the second support portion in the rotation axis direction of the drive gear. The second support member is disposed upstream of the first support member in a fastening direction, and includes a mounting portion extending so as to be in contact with the first support portion in the projection plane, the mounting portion including an attachment hole, the attachment hole being disposed at a position overlapping the fastening hole.

Abstract: An image forming apparatus is capable of suppressing deterioration in accuracy of control for switching a motor from forward to reverse rotation in a configuration in which a coupling having play in a rotation direction is interposed in a drive train between the motor and a driven member. The image forming apparatus includes a motor that rotationally drives a photosensitive drum and a developing sleeve; a coupling interposed in a drive train between the motor and the developing sleeve and/or a drive train between the motor and the photosensitive drum and having play in a rotation direction; and a CPU that controls the motor. The CPU rotates the motor forward at a speed V1 at the time of image formation, stops the motor after the end of the image formation, rotates the motor forward at a speed V2 lower than the speed V1, and then reversely rotates the motor.

Abstract: An image forming apparatus includes a driving unit including a driving source, a drive gear, a first support member that holds the driving source and includes a first support portion that supports one end portion of a rotation shaft of the drive gear, and a second support member that includes a second support portion that supports another end portion of the rotating shaft. The first support member includes a fastening hole disposed in a projection plane obtained by projecting the second support portion in the rotation axis direction of the drive gear. The second support member is disposed upstream of the first support member in a fastening direction, and includes a mounting portion extending so as to be in contact with the first support portion in the projection plane, the mounting portion including an attachment hole, the attachment hole being disposed at a position overlapping the fastening hole.

Abstract: An image forming apparatus includes a support frame, a driving device including a first supporting portion configured to hold the drive source on a first surface and configured to rotatably support the drive gear on a second surface, and a second supporting portion configured to support the drive gear with the first supporting portion, a board holding member disposed in a manner overlapping the first supporting portion in a rotational axis direction of the drive gear, and a third supporting portion disposed between the first supporting portion and the board holding member in the rotational axis direction, and configured to support the board holding member, one end of the third supporting portion being fixed to a side of the first surface of the first supporting portion by a first fastening member, another end of the third supporting portion being fixed to the board holding member by a second fastening member.

Abstract: Provided is an Oldham coupling having a play in a rotational direction and being capable of transmitting a driving force. An Oldham coupling 1 includes a developing drive gear 99 that is a first hub, a drive coupling 89 that is a second hub, and an intermediate member 3 that transmits a driving force between the developing drive gear 99 and the drive coupling 89. The developing drive gear 99 includes a protruded portion 99a that is fitted to a recessed portion 3a of the intermediate member 3 to transmit a driving force between the developing drive gear 99 and the intermediate member 3. When seen in a rotational axis direction of the Oldham coupling 1, the shape of a protruded portion 89a is a substantially rhombic shape.

Abstract: An image forming apparatus is provided, which is capable of suppressing deterioration in the accuracy of control for switching a motor from forward rotation to reverse rotation in a configuration in which a coupling having play in a rotation direction is interposed in a drive train between the motor and a driven member. The image forming apparatus includes: one motor 92a that rotationally drives a photosensitive drum 26 and a developing sleeve 71; a coupling that is interposed in at least one of a drive train between the motor 92a and the developing sleeve 71 and a drive train between the motor 92a and the photosensitive drum 26 and has play in a rotation direction; and a CPU 53 that controls the motor 92a. The CPU 53 rotates the motor 92a forward at a speed V1 at the time of image formation, stops the motor 92a after the end of the image formation, rotates the motor 92a forward at a speed V2 lower than the speed V1, and then reversely rotates the motor 92a.

Abstract: A motor includes: a bobbin having an insertion hole; a coil wound around the bobbin; a stator core having an excitation part that is inserted into the insertion hole; a rotor that is disposed rotatably with respect to the stator core; and a resin mold covering the bobbin, the coil, and the stator core. On a first opening end of the insertion hole, an exposed portion having an exposed surface that is exposed from the resin mold is formed. The exposed portion is positioned between the stator core and the resin mold.

Abstract: An image forming apparatus includes an image forming unit configured to form an image; a holding portion configured to hold the image forming unit; a supporting portion configured to support the holding portion; a fastening portion configured to fasten the holding portion and the supporting portion to each other; and an arcuate slit portion provided in at least one of the holding portion and the supporting portion and extending substantially about the fastening portion in a range at least not less than 180° and less than 360° around the fastening portion.

Abstract: An image forming apparatus includes a control portion that controls a drive speed of a first drive source, so that a speed of a sheet conveyed in a conveyance nip portion is greater than a speed of the sheet conveyed in a transfer nip portion, and a drive speed of a second drive source, so that the speed of the sheet conveyed in the transfer nip portion is greater than a speed of the sheet conveyed in a fixing nip portion. The control portion changes a rotation speed of a pair of conveyance members from a first speed to a second speed greater than the first speed after a first loop amount of the sheet formed between the transfer nip portion and the fixing nip portion becomes greater than a second loop amount of the sheet formed between the transfer nip portion and the conveyance nip portion.

Abstract: An image forming apparatus includes a sensor and a shutter to cover a window for the sensor. The shutter includes a detection hole to uncover the window and a cover portion to cover it. In an opening position of the shutter, the window and the hole are opposed to each other, and in a closing position of the shutter, the window and the cover portion are opposed to each other. A holder for the sensor includes a side wall opposed to a side of the sensor remote from a sheet feeding path and extended in a widthwise direction. As viewed in a horizontal direction perpendicular to the belt, the side wall is provided with a first area overlapping the hole in the closing position and a second area overlapping the window in the closing position. The first area is below the shutter and lower than the second area.

Abstract: A communication path that communicates with a first main pressure chamber is provided in a main piston and a piston rod. A check valve, which opens by being pressed by a booster piston and allows the communication path to communicate with a first sub-pressure chamber when the piston rod reaches a booster start position before a forward stroke end, is disposed in an end portion of the communication path. A plurality of steel balls are disposed in a coupling-member containing chamber formed in the booster piston. An engagement surface and an engagement groove, which engage with the steel balls when the booster piston moves forward due to an action of a pressure fluid supplied to the first sub-pressure chamber 11a through the communication path, are formed in the coupling-member containing chamber and an outer peripheral surface of the piston rod.

Abstract: An image forming apparatus includes a sensor, a shutter to cover a window for the sensor. The shutter includes a detection hole to uncover the window and a cover portion to cover it. In an opening position of the shutter, the window and the hole are opposed to each other, and in a closing position of the shutter, the window and the cover portion are opposed to each other. A holder for the sensor includes a side wall opposed to a side of the sensor remote from a sheet feeding path and extended in a widthwise direction. As viewed in a horizontal direction perpendicular to widthwise of the belt, the side wall is provided with a first area overlapping the hole in the closing position and a second area overlapping the window in the closing position. The first area is below the shutter and lower than the second area.

Abstract: A belt conveyance apparatus includes an endless belt conveyed while being supported by a plurality of support rollers in a tensioned state. The plurality of support rollers include a tension roller and a steering roller. The tension roller, which is disposed adjacent to and downstream of the steering roller in a conveyance direction of the endless belt, has a reverse crown shape in which end portions in a rotational axis direction each have an outer diameter larger than a middle portion.

Abstract: A communication path that communicates with a first main pressure chamber is provided in a main piston and a piston rod. A check valve, which opens by being pressed by a booster piston and allows the communication path to communicate with a first sub-pressure chamber when the piston rod reaches a booster start position before a forward stroke end, is disposed in an end portion of the communication path. A plurality of steel balls are disposed in a coupling-member containing chamber formed in the booster piston. An engagement surface and an engagement groove, which engage with the steel balls when the booster piston moves forward due to an action of a pressure fluid supplied to the first sub-pressure chamber 11a through the communication path, are formed in the coupling-member containing chamber and an outer peripheral surface of the piston rod.

Abstract: An apparatus comprises a flute, a base, and a thumb rest. The base is attached to the flute and defines a channel. The thumb rest is inserted into the channel and defines an elongate body. The thumb rest is positioned such that a flutist may rest a right thumb against the thumb rest while using conventional fingering to play the flute.

Abstract: A belt conveyance apparatus includes an endless belt conveyed while being supported by a plurality of support rollers in a tensioned state. The plurality of support rollers include a tension roller and a steering roller. The tension roller, which is disposed adjacent to and downstream of the steering roller in a conveyance direction of the endless belt, has a reverse crown shape in which end portions in a rotational axis direction each have an outer diameter larger than a middle portion.