Base material conveying device, printing apparatus, coating apparatus and base material roll diameter obtaining method

A base material conveying device, comprising:

• a conveyor which conveys a base material in the form of an elongated band;
• a winding roll on which the base material conveyed from the conveyor is wound;
• a driver which rotationally drives the winding roll to wind the base material on the winding roll;
• a conveying distance meter whish measures a conveying distance of the base material wound on the winding roll and conveyed;
• a diameter meter which includes a sensor facing the base material wound on the winding roll and measures a plurality of measured winding diameter values corresponding to the conveying distance by measuring a diameter of the base material wound on the winding roll a plurality of times by the sensor at the time of conveying the base material by the conveyor;
• a value acquirer which obtains an initial diameter value which is a value of the diameter of the base material wound on the winding roll before the conveyance of the base material by the conveyor is started and a thickness value of the base material;
• and
• a controller including:
• a winding diameter calculator which calculates a plurality of calculated winding diameter values corresponding to the conveying distance by calculating the value of the diameter of the base material wound on the winding roll a plurality of times at the time of conveying the base material by the conveyor based on the initial diameter value and the thickness value of the base material obtained by the value acquirer and the conveying distance measured by the conveying distance meter;
• a filter unit which smooths the plurality of measured winding diameter values corresponding to the conveying distance by a low-pass filter to extract a plurality of smoothed winding diameter values corresponding to the conveying distance;
• a difference calculator which calculates a plurality of differences corresponding to the conveying distance by performing an operation of calculating a difference between the calculated winding diameter value and the smoothed winding diameter value while compensating for a delay by the low-pass filter for the plurality of calculated winding diameter values and the plurality of smoothed winding diameter values;
• and
• a corrector which corrects the plurality of calculated winding diameter values corresponding to the conveying distance by the plurality of differences corresponding to the conveying distance.

A base material roll diameter obtaining method to obtain a diameter of a base material wound on an unwinding roll in a base material conveying device which conveys the base material unwound from the unwinding roll by a conveyor by rotationally driving the unwinding roll on which the base material in the form of an elongated band is wound, comprising:

• a value obtaining step of obtaining an initial diameter value which is a value of the diameter of the base material wound on the unwinding roll before the conveyance of the base material by the conveyor is started and a thickness value of the base material;
• a conveying distance measuring step of measuring a conveying distance of the base material unwound from the unwinding roll and conveyed;
• a diameter measuring step of measuring a plurality of measured winding diameter values corresponding to the conveying distance by measuring the diameter of the base material wound on the unwinding roll a plurality of times by a sensor facing the base material wound on the unwinding roll at the time of conveying the base material by the conveyor;
• a calculating step of calculating a plurality of calculated winding diameter values corresponding to the conveying distance by calculating the value of the diameter of the base material wound on the unwinding roll a plurality of times at the time of conveying the base material by the conveyor based on the initial diameter value and the thickness value of the base material obtained in the value obtaining step and the conveying distance measured in the conveying distance measuring step;
• a filtering step of smoothing the plurality of measured winding diameter values corresponding to the conveying distance by a low-pass filter to extract a plurality of smoothed winding diameter values corresponding to the conveying distance;
• a difference calculating step of calculating a plurality of differences corresponding to the conveying distance by performing an operation of calculating a difference between the calculated winding diameter value and the smoothed winding diameter value while compensating for a delay by the low-pass filter for the plurality of calculated winding diameter values and the plurality of smoothed winding diameter values;
• and
• a correcting step of correcting the plurality of calculated winding diameter values corresponding to the conveying distance by the plurality of differences corresponding to the conveying distance.

A base material roll diameter obtaining method to obtain a diameter of a base material wound on a winding roll in a base material conveying device which rotationally drives the winding roll to winds the base material, which is in the form of an elongated band and conveyed from a conveyor, on the winding roll, comprising:

• a value obtaining step of obtaining an initial diameter value which is a value of the diameter of the base material wound on the winding roll before the conveyance of the base material by the conveyor is started and a thickness value of the base material;
• a conveying distance measuring step of measuring a conveying distance of the base material wound by the winding roll and conveyed;
• a diameter measuring step of measuring a plurality of measured winding diameter values corresponding to the conveying distance by measuring the diameter of the base material wound on the winding roll a plurality of times by a sensor facing the base material wound on the winding roll at the time of conveying the base material by the conveyor;
• a calculating step of calculating a plurality of calculated winding diameter values corresponding to the conveying distance by calculating the value of the diameter of the base material wound on the winding roll a plurality of times at the time of conveying the base material by the conveyor based on the initial diameter value and the thickness value of the base material obtained in the value obtaining step and the conveying distance measured in the conveying distance measuring step;
• a filtering step of smoothing the plurality of measured winding diameter values corresponding to the conveying distance by a low-pass filter to extract a plurality of smoothed winding diameter values corresponding to the conveying distance;
• a difference calculating step of calculating a plurality of differences corresponding to the conveying distance by performing an operation of calculating a difference between the calculated winding diameter value and the smoothed winding diameter value corresponding to the same conveying distance while compensating for a delay by the low-pass filter caused in the plurality of smoothed winding diameter values corresponding to the conveying distance for the plurality of calculated winding diameter values and the plurality of smoothed winding diameter values;
• and
• a correcting step of correcting the plurality of calculated winding diameter values corresponding to the conveying distance by the plurality of differences corresponding to the conveying distance.