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A printing medium conveying technique is disclosed for moving a printing medium in a sub scanning direction. The technique involves controlling the moving of the printing medium through feedback control using a speed profile. The speed profile includes an accelerating region, a constant speed region

A printing medium conveying technique is disclosed for moving a printing medium in a sub scanning direction. The technique involves controlling the moving of the printing medium through feedback control using a speed profile. The speed profile includes an accelerating region, a constant speed region, a decelerating region, a constant low speed region, and a stopping operations region. The technique also involves switching the speed profile from the accelerating region to the constant speed region according to speed information; and switching the speed profile between the constant speed region, the decelerating region, the constant low speed region, and the stopping operations region according to the current distance from a target position.

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1. A printing medium conveying apparatus that is configured to move a printing medium in a sub scanning direction, the apparatus comprising: a drive pulley including a rotatable shaft;a belt arranged over the drive pulley and configured to rotate in correspondence with a rotation of the rotatable sh

1. A printing medium conveying apparatus that is configured to move a printing medium in a sub scanning direction, the apparatus comprising: a drive pulley including a rotatable shaft;a belt arranged over the drive pulley and configured to rotate in correspondence with a rotation of the rotatable shaft;a motor configured to move the printing medium by rotating the rotatable shaft; anda control unit that includes a speed profile and is configured to calculate the rotation of the rotatable shaft and control the moving of the printing medium through feedback control using the speed profile;wherein the speed profile includes an accelerating region, a constant speed region, a decelerating region, a constant low speed region, and a stopping operations region;the speed profile is switched from the accelerating region to the constant speed region according to speed information; andthe speed profile is switched between the constant speed region, the decelerating region, the constant low speed region, and the stopping operations region when a current position of the motor reaches a predetermined distance from a target position. 2. The printing medium conveying apparatus as claimed in claim 1, wherein a profile of the decelerating region is determined by a linear function of a difference of the current position of the motor and the target position, and a speed according to said profile is arranged to decrease as the current position comes closer to the target position. 3. The printing medium conveying apparatus as claimed in claim 2, wherein a target speed for decelerating from a first speed V1 to a second speed V2 in the decelerating region is determined by a function of an encoder pulse count value Pr which function is expressed as: Vt=(Pr×(V1−V2)/(P1−P2)−(P1×(V1−V2)/(P1−P2)−V1))/(Lp)wherein P1 denotes a count value at the first speed V1, P2 denotes a count value at the second speed V2, and Lp denotes an encoder pulse resolution. 4. A printing medium conveying method for moving a printing medium in a sub scanning direction via a motor, the method comprising: arranging a belt over a drive pulley, the drive pulley including a rotatable shaft;rotating the belt arranged over the drive pulley in correspondence with a rotation of the rotatable shaft to generate the moving of the printing medium;calculating the rotation of the rotatable shaft;controlling the moving of the printing medium through feedback control using a speed profile, which speed profile includes an accelerating region, a constant speed region, a decelerating region, a constant low speed region, and a stopping operations region;switching the speed profile from the accelerating region to the constant speed region according to speed information; andswitching the speed profile between the constant speed region, the decelerating region, the constant low speed region, and the stopping operations region when a current position of the motor reaches a predetermined distance from a target position. 5. The printing medium conveying method as claimed in claim 4, wherein a profile of the decelerating region is determined by a linear function of a difference of the current position of the motor and the target position, and a speed according to said profile is arranged to decrease as the current position comes closer to the target position. 6. The printing medium conveying method as claimed in claim 5, wherein a target speed for decelerating from a first speed V1 to a second speed V2 in the decelerating region is determined by a function of an encoder pulse count value Pr, which function is expressed as: Vt=(Pr×(V1−V2)/(P1−P2)−(P1×(V1−V2)/(P1−P2)−V1))/(Lp)wherein P1 denotes a count value at the first speed V1, P2 denotes a count value at the second speed V2, and Lp denotes an encoder pulse resolution. 7. A computer-readable medium containing a printing medium conveying program run on a computer for moving a printing medium in a sub scanning direction via a motor, the program being executed by the computer to perform a method, comprising: arranging a belt over a drive pulley, the drive pulley including a rotatable shaft;rotating the belt arranged over the drive pulley in correspondence with a rotation of the rotatable shaft to generate the moving of the printing medium;calculating the rotation of the rotatable shaft;controlling the moving of the printing medium through feedback control using a speed profile, which speed profile includes an accelerating region, a constant speed region, a decelerating region, a constant low speed region, and a stopping operations region;switching the speed profile from the accelerating region to the constant speed region according to speed information; andswitching the speed profile between the constant speed region, the decelerating region, the constant low speed region, and the stopping operations region when a current position of the motor reaches a predetermined distance from a target position. 8. The printing medium conveying program as claimed in claim 7, wherein a profile of the decelerating region is determined by a linear function of a difference of the current position of the motor and the target position, and a speed according to said profile is arranged to decrease as the current position comes closer to the target position. 9. The printing medium conveying program as claimed in claim 8, wherein a target speed for decelerating from a first speed V1 to a second speed V2 in the decelerating region is determined by a function of an encoder pulse count value Pr, which function is expressed as: Vt=(Pr×(V1−V2)/(P1−P2)−(P1×(V1−V2)/(P1−P2)−V1))/(Lp)wherein P1 denotes a count value at the first speed V1, P2 denotes a count value at the second speed V2, and Lp denotes an encoder pulse resolution. 10. The printing medium conveying apparatus as claimed in claim 1, further comprising: an encoder configured to count a number of revolutions of the motor to determine the current position of the motor. 11. The printing medium conveying apparatus as claimed in claim 1, wherein the target position is a position of the motor at which the motor stops rotating in the stopping operations region. 12. The printing medium conveying method as claimed in claim 4, further comprising: counting a number of revolutions of the motor to determine the current position of the motor. 13. The printing medium conveying method as claimed in claim 4, wherein the target position is a position of the motor at which the motor stops rotating in the stopping operations region. 14. The printing medium conveying program as claimed in claim 7, further comprising: counting a number of revolutions of the motor to determine the current position of the motor. 15. The printing medium conveying program as claimed in claim 7, wherein the target position is a position of the motor at which the motor stops rotating in the stopping operations region. 16. The printing medium conveying apparatus as claimed in claim 1, further comprising: an encoder arranged coaxially with the drive pulley; andan encoder sensor configured to detect a slit formed on the encoder,wherein the control unit calculates the rotation of the rotatable shaft by counting a number of outputs of the encoder sensor. 17. The printing medium conveying method as claimed in claim 4, further comprising: arranging an encoder coaxially with the drive pulley; anddetecting a slit formed on the encoder with an encoder sensor,wherein the calculating the rotation of the rotatable shaft includes counting a number of outputs of the encoder sensor. 18. The printing medium conveying program as claimed in claim 7, further comprising: arranging an encoder coaxially with the drive pulley; anddetecting a slit formed on the encoder with an encoder sensor,wherein the calculating the rotation of the rotatable shaft includes counting a number of outputs of the encoder sensor.