Abstract: An image forming apparatus includes a stacking portion, a pickup roller, a motor, an image forming unit, and a controller. Upon receiving an instruction for starting a first image forming job, the controller performs an initial operation of supplying current to a motor winding of the motor in a stop state and determining a phase of the rotor based on the flowing current. Based on the determined phase, the controller supplies current to rotate the rotor from its stop state and holds the rotor at a first phase when the first job ends. Upon receiving start instructions for a second image forming job within a period until a predetermined time elapses from when the rotor is held at the first phase, the controller rotates the rotor without performing the initial operation. The controller stops supplying current to the winding if no instructions are not received for starting the second job.

Abstract: An image forming apparatus includes a stacking portion, a pickup roller, a motor, an image forming unit, and a controller. Upon receiving an instruction for starting a first image forming job, the controller performs an initial operation of supplying current to a motor winding of the motor in a stop state and determining a phase of the rotor based on the flowing current. Based on the determined phase, the controller supplies current to rotate the rotor from its stop state and holds the rotor at a first phase when the first job ends. Upon receiving start instructions for a second image forming job within a period until a predetermined time elapses from when the rotor is held at the first phase, the controller rotates the rotor without performing the initial operation. The controller stops supplying current to the winding if no instructions are not received for starting the second job.

Abstract: An image forming apparatus includes a transfer unit, a fixing unit having a first rotating member and a second rotating member, and includes a first motor, a second motor, a drive transmission unit that operates in a first state and in a second state, and an adjustment member that adjusts a shaft-to-shaft distance and moves between a first position and a second position. In a state where a driving force of the second motor is not transmitted to the adjustment member located at the second position, the adjustment member maintains the shaft-to-shaft distance at a second distance that is shorter than a first distance. In a state where the drive transmission unit operates in the first state and the shaft-to-shaft distance is maintained at the second distance by the adjustment member located at the second position, the first rotating member is driven by both the first and second motors.

Abstract: An image forming apparatus includes a transfer unit, a fixing unit having a first rotating member and a second rotating member, and includes a first motor, a second motor, a drive transmission unit that operates in a first state and in a second state, and an adjustment member that adjusts a shaft-to-shaft distance and moves between a first position and a second position. In a state where a driving force of the second motor is not transmitted to the adjustment member located at the second position, the adjustment member maintains the shaft-to-shaft distance at a second distance that is shorter than a first distance. In a state where the drive transmission unit operates in the first state and the shaft-to-shaft distance is maintained at the second distance by the adjustment member located at the second position, the first rotating member is driven by both the first and second motors.

Abstract: A sheet conveyance apparatus includes a stacking unit having a sheet, a feeding unit, a conveyance roller to convey a sheet fed by the feeding unit, a motor to drive the conveyance roller, a phase determiner, first and second controllers, and a discriminator. The feeding unit feeds the sheet. The phase determiner determines a motor rotor rotational phase. The first controller controls a drive current flowing in a motor winding to reduce a deviation between an instructed phase of the motor rotor and the determined rotational phase. The second controller controls to perform a first drive for driving the conveyance roller for a predetermined time before a feeding unit feed operation is started. The discriminator discriminates presence or absence of the sheet at a nip portion of the conveyance roller based on a value of a parameter corresponding to load torque applied to the rotor during the first drive.

Abstract: A sheet conveyance apparatus includes a stacking unit having a sheet, a feeding unit, a conveyance roller to convey a sheet fed by the feeding unit, a motor to drive the conveyance roller, a phase determiner, first and second controllers, and a discriminator. The feeding unit feeds the sheet. The phase determiner determines a motor rotor rotational phase. The first controller controls a drive current flowing in a motor winding to reduce a deviation between an instructed phase of the motor rotor and the determined rotational phase. The second controller controls to perform a first drive for driving the conveyance roller for a predetermined time before a feeding unit feed operation is started. The discriminator discriminates presence or absence of the sheet at a nip portion of the conveyance roller based on a value of a parameter corresponding to load torque applied to the rotor during the first drive.

Abstract: A position estimation unit of a motor control apparatus includes a counter electromotive voltage estimation unit configured to estimate a counter electromotive voltage generated in a motor based on generated voltage and current of the motor, and an arc tangent calculation unit configured to perform an arc tangent calculation using coordinate data on a two-dimensional plane based on the estimated counter electromotive voltage to calculate an angle of deviation. The arc tangent calculation unit includes a rotation calculation unit configured to repeatedly perform a rotation calculation of coordinate data on a fundamental wave and a harmonic; a rotation direction judgment unit configured to judge a rotation direction of a subsequent rotation calculation based on a result of the rotation calculation of the rotation calculation unit; and a deviation angle calculation unit configured to calculate a total of rotation angles obtained as a result of the rotation calculation.

Abstract: A motor control apparatus includes: a unit configured to determine a counter-electromotive voltage in a winding of a motor; a unit configured to determine a rotational position of a rotor of the motor based on the counter-electromotive voltage; a unit configured to determine a first velocity of the rotor, based on change in the rotational position; a correction unit configured to obtain a second velocity by correcting the first velocity based on a harmonic component included in the first velocity; and a driving unit configured to drive the motor based on the second velocity and the rotational position. The correction unit includes a unit configured to obtain the second velocity by reducing error in the first velocity that occurs due to the harmonic component.

Abstract: A position estimation unit of a motor control apparatus includes a counter electromotive voltage estimation unit configured to estimate a counter electromotive voltage generated in a motor based on generated voltage and current of the motor, and an arc tangent calculation unit configured to perform an arc tangent calculation using coordinate data on a two-dimensional plane based on the estimated counter electromotive voltage to calculate an angle of deviation. The arc tangent calculation unit includes a rotation calculation unit configured to repeatedly perform a rotation calculation of coordinate data on a fundamental wave and a harmonic; a rotation direction judgment unit configured to judge a rotation direction of a subsequent rotation calculation based on a result of the rotation calculation of the rotation calculation unit; and a deviation angle calculation unit configured to calculate a total of rotation angles obtained as a result of the rotation calculation.

Abstract: A motor control apparatus includes: a unit configured to determine a counter-electromotive voltage in a winding of a motor; a unit configured to determine a rotational position of a rotor of the motor based on the counter-electromotive voltage; a unit configured to determine a first velocity of the rotor, based on change in the rotational position; a correction unit configured to obtain a second velocity by correcting the first velocity based on a harmonic component included in the first velocity; and a driving unit configured to drive the motor based on the second velocity and the rotational position. The correction unit includes a unit configured to obtain the second velocity by reducing error in the first velocity that occurs due to the harmonic component.

Abstract: A driving transmission device includes a motor, a first pulley, a second pulley, an endless belt which is wound on the first pulley and the second pulley, dielectric layers disposed between the endless belt and the first pulley and between the endless belt and the second pulley, and a power source unit. A length of a portion of the endless belt which is wound on the second pulley is longer than a length of a portion of the endless belt which is wound on the first pulley. An amount of current supplied from the second pulley to the endless belt in a region in which the endless belt is wound on the second pulley is smaller than an amount of current supplied from the first pulley to the endless belt in a region in which the endless belt is wound on the first pulley.

Abstract: A driving transmission device includes a motor, a first pulley to be rotated by the motor, a second pulley connected to a rotating member, an endless belt wound on the first pulley and the second pulley, a dielectric layer provided between the endless belt and the first pulley and between the endless belt and the second pulley, and a power supply unit configured to apply a voltage to the first pulley. The first pulley, the endless belt, and the second pulley are connected in series. A length by which the endless belt is wound on the second pulley is larger than a length by which the endless belt is wound on the first pulley. A voltage applied to the second pulley is lower than the voltage applied to the first pulley.

Abstract: A belt driving device includes first and second steering rollers to stretch an endless belt, first and second pivoting mechanisms, and first and second detecting members to detect a position of the belt A first setting portion sets first and second pivoting instruction values through which the first and second steering rollers are pivoted in the same direction, and a second setting portion sets third and fourth pivoting instruction values through which the first and second steering rollers are pivoted in the opposite directions. A controller pivots the first steering roller by the first pivoting mechanism on the basis of an addition value of the first pivoting instruction value and the third pivoting instruction value, and pivots the second steering roller by the second pivoting mechanism on the basis of an addition value of the second pivoting instruction value and the fourth pivoting instruction value.

Abstract: A driving transmission device includes a motor, a first pulley to be rotated by the motor, a second pulley connected to a rotating member, an endless belt wound on the first pulley and the second pulley, a dielectric layer provided between the endless belt and the first pulley and between the endless belt and the second pulley, and a power supply unit configured to apply a voltage to the first pulley. The first pulley, the endless belt, and the second pulley are connected in series. A length by which the endless belt is wound on the second pulley is larger than a length by which the endless belt is wound on the first pulley. A voltage applied to the second pulley is lower than the voltage applied to the first pulley.

Abstract: A driving transmission device includes a motor, a first pulley, a second pulley, an endless belt which is wound on the first pulley and the second pulley, dielectric layers disposed between the endless belt and the first pulley and between the endless belt and the second pulley, and a power source unit. A length of a portion of the endless belt which is wound on the second pulley is longer than a length of a portion of the endless belt which is wound on the first pulley. An amount of current supplied from the second pulley to the endless belt in a region in which the endless belt is wound on the second pulley is smaller than an amount of current supplied from the first pulley to the endless belt in a region in which the endless belt is wound on the first pulley.

Abstract: A belt driving device for driving an endless belt includes rollers configured to stretch the belt, the rollers including first and second steering rollers being provided in an upstream side and a downstream side of an image receiving surface of the belt for receiving a image, respectively, and being configured to change a position of the belt in a direction crossing with a moving direction of the belt by inclining respectively; a pivoting unit configured to pivot the first and second steering rollers, respectively; a detecting unit for detecting an inclination amount of the belt with respect to a feeding direction of the belt; and a controller configured to pivot the first and second steering rollers in the same direction by the pivoting unit on the basis of a result of detection of the detecting unit.