Method and device for cutting off band-like paper member and controller of the device

A cut off control device for band-like paper, which device controls a preceding knife driving motor for rotationally driving a preceding knife cylinder on whose peripheral surface a preceding helical knife is provided and also a following knife driving motor for rotationally driving a following knife cylinder on whose peripheral surface a following helical knife is provided, said control device comprising:

• a speed pattern generator, to which a paper feeding speed of the band-like paper and the sheet length to be cut off is input, for generating rotational speed patterns of the preceding knife driving motor and the following knife driving motor based on the input paper feeding speed and the input sheet length to be cut off and for outputting a speed instruction value;
• a comparator which compares the speed instruction value from said speed pattern generator with a detected speed of the preceding knife driving motor or the following knife driving motor;
• an instruction torque computing unit which computes rotational torque instruction values for the preceding knife driving motor and the following knife driving motor based on a signal from said comparator;
• a cutting torque computing unit which computes cutting torque of the preceding knife driving motor and the following knife driving motor;
• a to-be-given torque pattern generator which distributes the cutting torque sent from said cutting torque computing unit, and generates a to-be-given torque pattern based on the paper feeding speed of the band-like paper and the sheet length to be cut off, and outputs a to-be-given torque instruction value;
• an instruction torque subtractor unit which subtracts the to-be-given torque instruction value, output from said to-be-given torque pattern generator, from the rotational torque instruction value computed by said instruction torque computing unit;
• a preceding power amplifier which controls the preceding knife driving motor based on a computation result obtained by said instruction torque subtractor;
• an instruction torque adder which adds the rotational torque instruction value, computed by said instruction torque computing unit, to the to-be-given torque instruction value computed by said to-be-given torque pattern generator;
• and
• a following power amplifier which controls the following knife driving motor based on a computation result obtained by said instruction torque adder.

A cut off apparatus for cutting off band-like paper, comprising:

• a preceding knife cylinder on whose peripheral surface a preceding helical knife is provided;
• a following knife cylinder on whose peripheral surface a following helical knife, which cuts off band-like paper in cooperation with the preceding knife, is provided;
• a preceding gear attached at one of the opposite ends of the rotation axis of the preceding knife cylinder;
• a following gear attached at one of the opposite ends of the rotation axis of the following knife cylinder;
• a preceding drive gear which has a meshing engagement with said preceding gear;
• a following drive gear which has a meshing engagement with said following gear;
• a preceding knife driving motor which rotationally drives said preceding drive gear;
• a following knife driving motor which rotationally drives said following drive gear, said following knife driving motor having the same rated capacity as that of said preceding knife driving motor;
• and
• a cut off control device which individually controls said preceding knife driving motor and said following knife driving motor.

A cut off apparatus for cutting off band-like paper, comprising:

• a preceding knife cylinder on whose peripheral surface a preceding helical knife is provided;
• a following knife cylinder on whose peripheral surface a following helical knife, which cuts off band-like paper in cooperation with the preceding knife, is provided;
• a preceding gear attached at one of the opposite ends of the rotation axis of the preceding knife cylinder;
• a following gear attached at one of the opposite ends of the rotation axis of the following knife cylinder;
• a preceding drive gear which has a meshing engagement with said preceding gear;
• a following drive gear which has a meshing engagement with said following gear;
• a preceding knife driving motor which rotationally drives said preceding drive gear;
• a following knife driving motor which rotationally drives said following drive gear;
• and
• a cut off control device which individually controls said preceding knife driving motor and said following knife driving motor,
• wherein at least either one of said preceding gear and said following gear has one or more teeth shaped so that said preceding gear and said following gear do not come into contact with each other after passing a specified distance from initiation of a cut off operation, said one or more teeth being provided at a portion of said gear relating to the cut off operation performed by said preceding and following knives in cooperation with each other.

A cut off apparatus for cutting off band-like paper, comprising:

• a preceding knife cylinder on whose peripheral surface a preceding helical knife is provided;
• a following knife cylinder on whose peripheral surface a following helical knife, which cuts off band-like paper in cooperation with the preceding knife, is provided;
• a preceding gear attached at one of the opposite ends of the rotation axis of the preceding knife cylinder;
• a following gear attached at one of the opposite ends of the rotation axis of the following knife cylinder;
• a preceding drive gear which has a meshing engagement with said preceding gear;
• a following drive gear which has a meshing engagement with said following gear;
• a preceding knife driving motor which rotationally drives said preceding drive gear;
• a following knife driving motor which rotationally drives said following drive gear;
• and
• a cut off control device which individually controls said preceding knife driving motor and said following knife driving motor,
• wherein a part of at least either one of said preceding gear and said following gear has no teeth so that said preceding gear and said following gear do not come into contact with each other after passing a specified distance from initiation of a cut off operation, said part without teeth being provided at a portion of said gear relating to the cut off operation performed by said preceding and following knives in cooperation with each other.