Paper cutter for variable format

A method of consecutively cutting sheets of variable length and at variable speed from a continuous web fed from an upstream location to a downstream location along a predetermined path to a cutter mechanism having a fixed blade at a first angle to the path and having a rotary blade at a second opposite angle to the path so that during its annular rotation through a cutting arc, the rotary blade makes moving cutting point contact with the fixed blade to make a cut laterally across the web to cut the web into the sheets, said method comprising the steps of:

• feeding the web by means of pinch rollers past the cutting mechanism at a speed indicative of a number of sheets to be cut per unit of time;
• varying the speed of the pinch rollers to vary the number of sheets cut per unit of time;
• sensing a relative rotational position between the rotary blade and the pinch rollers;
• rotating the rotary blade at a first constant rotational speed through the cutting arc so that the relationship of the web speed with respect to the movement of the cutting point along the fixed blade results in the formation of a predetermined angular cut across the web;
• rotating the rotary blade at a second variable rotational speed from the end of the angular rotation through the cutting arc in response to the sensed relative rotational position of the rotary blade to the pinch rollers to position the rotary blade at a predetermined location prior to the beginning of a next angular rotation through the cutting arc for making a next cut at a desired location along the web to cut sheets to a desired length:
• simultaneously controlling the rotation of the pinch rollers and the rotation of the rotary blade to simultaneously vary both the speed at which the web is cut into sheets and the format of each sheet;
• providing a first sensor upstream from the cutter mechanism at a predetermined distance;
• determining a format of each sheet to be cut from the web which corresponds to the indicia positioned thereon;
• sensing the position of a leading edge of the web by the first sensor as it moves along the path;
• sensing the position of the indicia adjacent the leading edge with a second sensor;
• and
• cutting the web at a desired position indicative of the sensed position of the leading edge and the adjacent indicia.