A sheet processing machine stores sheets transported by a transport unit. The sheet processing machine includes: a reel on which a first end side of a tape is wound; a first stepper motor that rotates the reel about a rotation axis of the reel; a drum configured to wind up a second end side of the tape together with the sheets to form a winding body together with the tape and the sheets; a second stepper motor that rotates the drum about a rotation axis of the drum; and circuitry configured to change an interval between the sheets wound on the drum by controlling a rotation of the first stepper motor and the second stepper motor based on a parameter indicating a condition of the winding body.

A timing specifying device includes count processing circuitry to count an input reference clock; and timing control circuitry configured to set a parameter having an integer part and a fractional part in the count processing circuitry. The count processing circuitry counts the reference clock, outputs a timing signal indicating that a time corresponding to an integer value has passed, and counts a value corresponding to the fractional part at a timing at which the timing signal is output. The integer value is a value indicated by the integer part. The count processing circuitry stops counting of the reference clock when a value obtained by counting the value corresponding to the fractional part carries over from a fraction.

A PWM signal generation unit generates a PWM signal based on a driving voltage so that a midpoint of the longer period out of an H level period and an L level period in each PWM period matches a midpoint of the PWM period. FETs of a full bridge circuit (a driving circuit) are driven according to a PWM signal, and a driving current that corresponds to an A-phase is supplied to a stepping motor. A current detector detects a driving current flowing through an A-phase winding of the motor based on a voltage that is generated across a shunt resistor, at a fixed time point that is in each PWM period and in the H level or L level period that is at the center of the PWM period.

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 processing machine stores sheets transported by a transport unit. The sheet processing machine includes: a reel on which a first end side of a tape is wound; a first stepper motor that rotates the reel about a rotation axis of the reel; a drum configured to wind up a second end side of the tape together with the sheets to form a winding body together with the tape and the sheets; a second stepper motor that rotates the drum about a rotation axis of the drum; and circuitry configured to change an interval between the sheets wound on the drum by controlling a rotation of the first stepper motor and the second stepper motor based on a parameter indicating a condition of the winding body.

A sheet processing machine stores sheets transported by a transport unit. The sheet processing machine includes: a reel on which a first end side of a tape is wound; a first stepper motor that rotates the reel about a rotation axis of the reel; a drum configured to wind up a second end side of the tape together with the sheets to form a winding body together with the tape and the sheets; a second stepper motor that rotates the drum about a rotation axis of the drum; and circuitry configured to change an interval between the sheets wound on the drum by controlling a rotation of the first stepper motor and the second stepper motor based on a parameter indicating a condition of the winding body.

A timing specifying device includes count processing circuitry to count an input reference clock; and timing control circuitry configured to set a parameter having an integer part and a fractional part in the count processing circuitry. The count processing circuitry counts the reference clock, outputs a timing signal indicating that a time corresponding to an integer value has passed, and counts a value corresponding to the fractional part at a timing at which the timing signal is output. The integer value is a value indicated by the integer part. The count processing circuitry stops counting of the reference clock when a value obtained by counting the value corresponding to the fractional part carries over from a fraction.

A sheet conveying apparatus includes: a plurality of driving parts each connected to one end of corresponding one of a respective plurality of rotating shafts; a first torque adjuster connected to another end of each of the plurality of rotating shafts, the first torque adjuster applying first torque to the plurality of driving parts; a second torque adjuster that applies, to the driving parts, second torque for adjusting the first torque to be applied to the driving parts by the first torque adjuster; and a hardware processor that controls the second torque to be applied to the driving parts in the second torque adjuster in accordance with a number of revolutions of the driving part.

A sheet processing machine stores sheets transported by a transport unit. The sheet processing machine includes: a reel on which a first end side of a tape is wound; a first stepper motor that rotates the reel about a rotation axis of the reel; a drum configured to wind up a second end side of the tape together with the sheets to form a winding body together with the tape and the sheets; a second stepper motor that rotates the drum about a rotation axis of the drum; and circuitry configured to change an interval between the sheets wound on the drum by controlling a rotation of the first stepper motor and the second stepper motor based on a parameter indicating a condition of the winding body.

A sheet conveyance device including: a conveyance roller that conveys a sheet; a motor that rotationally drives the conveyance roller at a constant speed; a central processing unit (CPU) that: periodically acquires temperature increase rates for the motor from a start of sheet conveyance, the temperature increase rates depending on magnitudes of effective current applied to the motor, the effective current depending on loads during sheet conveyance; and estimates a current temperature of the motor based on a cumulative value calculated from the temperature increase rates and time elapsed from the start of sheet conveyance; and a controller that executes a motor temperature control based on the estimated temperature of the motor.