A paper conveying apparatus and an image forming apparatus are described which can appropriately convey a sheet when the sheet is restarted after forming a loop. The paper conveying apparatus includes a conveying roller pair in the upstream side of a loop roller pair, a stepping motor for rotationally driving the conveying roller pair, and a processor for controlling rotation of the stepping motor by controlling pulse signals and excitation current supplied to the stepping motor. This processor halts rotation of the conveying roller pair by stopping output of the pulse signals when loop formation of the sheet is completed, and switches the excitation current to a lower current value which is lower than a reference current value at which excitation is turned on.

A sheet conveying apparatus capable of continuing conveyance of sheets without causing a jam even when a switching member performs an operation for switching a conveyance path again. A switching member is disposed at a branching point of a conveyance path through which the sheet is conveyed by a conveying unit, and is operated by a drive unit for witching a destination of conveyance of the sheet. A controller causes the drive unit to operate the switching member, and performs a checking operation for checking a state of the drive unit based on an output from a sensor that detects a state of the switching member. The controller controls a sheet conveyance interval between a first sheet conveyed by the conveying unit and a second sheet conveyed following the first sheet, according to a result of the checking operation.

A sheet conveying apparatus capable of continuing conveyance of sheets without causing a jam even when a switching member performs an operation for switching a conveyance path again. A switching member is disposed at a branching point of a conveyance path through which the sheet is conveyed by a conveying unit, and is operated by a drive unit for witching a destination of conveyance of the sheet. A controller causes the drive unit to operate the switching member, and performs a checking operation for checking a state of the drive unit based on an output from a sensor that detects a state of the switching member. The controller controls a sheet conveyance interval between a first sheet conveyed by the conveying unit and a second sheet conveyed following the first sheet, according to a result of the checking operation.

A document conveyance apparatus includes a document conveyance section, a cover, an opening and closing detection sensor, a document detection sensor, and a control section. The control section detects opening and closing of the cover on the basis of an output value of the opening and closing detection sensor and detects whether or not there is a document in a predetermined detection position on the basis of the output value of the document detection sensor. If, when the output value of the document detection sensor has changed from a value indicating an opened state of the cover to a value indicating a closed state thereof, the output value of the document detection sensor is a value indicating that there is the document, the control section detects a half-closed state where the cover is not completely closed.

A document conveyance apparatus includes a document conveyance section, a cover, an opening and closing detection sensor, a document detection sensor, and a control section. The control section detects opening and closing of the cover on the basis of an output value of the opening and closing detection sensor and detects whether or not there is a document in a predetermined detection position on the basis of the output value of the document detection sensor. If, when the output value of the document detection sensor has changed from a value indicating an opened state of the cover to a value indicating a closed state thereof, the output value of the document detection sensor is a value indicating that there is the document, the control section detects a half-closed state where the cover is not completely closed.

The object of the present invention is to propose a novel device and a novel method to allow the transportation of printable substrates precisely, suited to substrates of various types, sizes and thicknesses. Furthermore, the invention is suited to printing machines that involve no contact with the substrate, such as inkjet printing machines.

An image forming apparatus is provided. Sheets, a plurality of which form a set, are contained in each of containers, and sheets are fed from the corresponding containers. If a first sheet to be fed is in the same layer as a second sheet that was fed from the containers last time, the first sheet is fed from a set that included the second sheet in the containers is fed. If the layer of the first sheet is higher than the layer of the second sheet that was fed from the containers last time, all remaining sheets in the set that included the second sheet are discharged from the containers.

An image forming apparatus is provided. Sheets, a plurality of which form a set, are contained in each of containers, and sheets are fed from the corresponding containers. If a first sheet to be fed is in the same layer as a second sheet that was fed from the containers last time, the first sheet is fed from a set that included the second sheet in the containers is fed. If the layer of the first sheet is higher than the layer of the second sheet that was fed from the containers last time, all remaining sheets in the set that included the second sheet are discharged from the containers.

Temperature-dependent motor control device, including: a motor controller configured to switch a motor control state among an activated state in which the motor is activated by a first current, an activation stopped state in which activation of the motor is stopped by stopping current supply, and an activation suspended state in which activation of the motor is suspended with a second current smaller than the first current kept supplied; and a temperature estimator configured to calculate an estimated motor temperature value and to perform a first calculation for gradually increasing the estimated value when the motor is in the activated state, a second calculation for gradually decreasing the estimated value when the motor is in the activation stopped state, and a third calculation for gradually decreasing the estimated value at a rate of decrease lower than that in the second calculation when the motor is in the activation suspended state.

Temperature-dependent motor control device, including: a motor controller configured to switch a motor control state among an activated state in which the motor is activated by a first current, an activation stopped state in which activation of the motor is stopped by stopping current supply, and an activation suspended state in which activation of the motor is suspended with a second current smaller than the first current kept supplied; and a temperature estimator configured to calculate an estimated motor temperature value and to perform a first calculation for gradually increasing the estimated value when the motor is in the activated state, a second calculation for gradually decreasing the estimated value when the motor is in the activation stopped state, and a third calculation for gradually decreasing the estimated value at a rate of decrease lower than that in the second calculation when the motor is in the activation suspended state.