Sheet conveying apparatus and image forming apparatus

A sheet conveying apparatus comprising:

• a conveying roller configured to convey a sheet;
• an abutment member against which a leading end of the sheet conveyed by the conveying roller abuts, the abutment member being provided at a downstream side of the conveying roller in a conveying direction in which the sheet is conveyed;
• a motor configured to drive the conveying roller;
• a phase determiner configured to determine a rotation phase of a rotor of the motor;
• and
• a controller configured to control the motor by controlling a value of a torque current component and a value of an excitation current component so that a difference between an instruction phase representing a target phase of the rotor and the rotation phase determined by the phase determiner is decreased, the torque current component being a current component having a current value represented in a rotating coordinate system based on the rotation phase, which generates torque in the rotor, and the excitation current component being a current component having a current value represented in the rotating coordinate system based on the rotation phase, which affects a strength of a magnetic flux through a winding of the motor,
• wherein the controller continues driving of the motor if the value of the torque current component is lower than a predetermined value when the conveying roller conveys the sheet in a state in which the leading end of the sheet abuts against the abutment member to deflect the sheet and stops the driving of the motor if the value of the torque current component is higher than or equal to the predetermined value when the conveying roller conveys the sheet in a state in which the leading end of the sheet abuts against the abutment member to deflect the sheet.

A document reading apparatus comprising:

• a document tray in which an original document is stacked;
• a conveying roller configured to convey the original document stacked in the document tray;
• a reading unit configured to read the original document conveyed by the conveying roller;
• an abutment member against which a leading end of a sheet conveyed by the conveying roller abuts, the abutment member being provided at a downstream side of the conveying roller and at an upstream side of the reading unit in a conveying direction in which the sheet is conveyed;
• a motor configured to drive the conveying roller;
• a phase determiner configured to determine a rotation phase of a rotor of the motor;
• a controller configured to control the motor by controlling a value of a torque current component and a value of an excitation current component so that a difference between an instruction phase representing a target phase of the rotor and the rotation phase determined by the phase determiner is decreased, the torque current component being a current component having a current value represented in a rotating coordinate system based on the rotation phase, which generates torque in the rotor, and the excitation current component being a current component having a current value represented in the rotating coordinate system based on the rotation phase, which affects a strength of a magnetic flux through a winding of the motor;
• and
• a torque determiner configured to determine load torque exerted on the rotor,
• wherein the controller continues driving of the motor if the load torque determined by the torque determiner is lower than predetermined torque when the conveying roller conveys the sheet in a state in which the leading end of the sheet abuts against the abutment member to deflect the sheet and stops the driving of the motor if the load torque determined by the torque determiner is higher than or equal to the predetermined torque when the conveying roller conveys the sheet in a state in which the leading end of the sheet abuts against the abutment member to deflect the sheet.

An image forming apparatus comprising:

• a conveying roller configured to convey a recording medium;
• an image forming unit configured to form an image on the recording medium conveyed by the conveying′ roller;
• an abutment member against which a leading end of a sheet conveyed by the conveying roller abuts, the abutment member being provided at a downstream side of the conveying roller in a conveying direction in which the sheet is conveyed;
• a motor configured to drive the conveying roller;
• a phase determiner configured to determine a rotation phase of a rotor of the motor;
• a controller configured to control the motor by controlling a value of a torque current component and a value of an excitation current component so that a difference between an instruction phase representing a target phase of the rotor and the rotation phase determined by the phase determiner is decreased, the torque current component being a current component having a current value represented in a rotating coordinate system based on the rotation phase, which generates torque in the rotor, and the excitation current component being a current component having a current value represented in the rotating coordinate system based on the rotation phase, which affects a strength of a magnetic flux through a winding of the motor;
• and
• a torque determiner configured to determine load torque exerted on the rotor,
• wherein the controller continues driving of the motor if the load torque determined by the torque determiner is lower than predetermined torque when the conveying roller conveys the sheet in a state in which the leading end of the sheet abuts against the abutment member to deflect the sheet and stops the driving of the motor if the load torque determined by the torque determiner is higher than or equal to the predetermined torque when the conveying roller conveys the sheet in a state in which the leading end of the sheet abuts against the abutment member to deflect the sheet.