Web splicing method and web splicing apparatus

A splicing apparatus, comprising:

• a first driver operable to spin a first roll of web;
• a second driver operable to spin a second roll of web;
• a splicer operable to connect a second web fed out from the second roll to a first web fed out from the first roll, and cut off the first web;
• an accumulator comprising a movable roller and a fixed roller, the accumulator operable to store at least one of the first web and the second web between the movable roller and the fixed roller;
• a first sensor operable to sense a position of the movable roller;
• a second sensor operable to sense spinning information regarding a number of turns the second driver is spun per unit time;
• and
• a controller operable to control a rotational speed of the first driver and that of the second driver, wherein after the first web is spliced with the second web, the controller is operable to calculate a first diameter of the second roll based on a positional change of the movable roller, information regarding an angular velocity of the second driver and a web flow velocity at a position downstream of the accumulator and wherein the controller is further operable to calculate a second diameter of the second roll based on the first diameter of the second roll, the spinning information, and an amount of time that has passed from when the first diameter of the second roll is calculated.