Universal roll-fed label cutter

A method of operating a labeling machine which cuts individual labels from a roll of labels and applies them to containers, the labeling machine having means for continuously and independently controlling the surface speeds of a vacuum drum, a cutter drum, and a feed roller, the method comprising the steps of:

• rotating the vacuum drum at a generally constant surface speed;
• transporting a label strip off of the label roll at a label feed rate, said label feed rate being slower than the surface speed of the vacuum drum;
• and
• varying the cutter drum surface speed during distinct intervals of a label cutting cycle, the cutter drum having a lower surface speed during the interval in the cycle in which the cutter drum cuts a label, the cutter drum having a higher surface speed during the interval in the cycle in which the cutter drum transfers a cut label to the vacuum drum.

An apparatus for cutting individual labels from a continuous roll of labels before applying them to containers, the apparatus comprising:

• a microprocessor;
• a rotary mounted feed roller driven by a first servomotor, said feed roller having a generally cylindrical shape and having a central axis about which it rotates;
• a rotary mounted cutter drum, said cutter drum having a generally cylindrical shape and having a central axis about which it rotates, said cutter drum further having means for cutting labels from the label roll;
• a rotary mounted vacuum drum, said vacuum drum having a generally cylindrical shape and having a central axis about which it rotates, said vacuum drum further having means for securing a cut label to the vacuum drum outer surface using suction;
• said first servomotor rotatably mounted to said feed roller about said feed roller central axis;
• said first servomotor electrically connected to said microprocessor whereby said microprocessor controls the rotational speed of said first servomotor and rotates said feed roller at varying surface speeds during the label cutting cycle, said feed roller surface speed remaining slightly less than said cutter drum speed, the surface speed of said feed roller tracking the surface speed of the cutter drum throughout the label cutting cycle;
• a feed roller encoder means for sensing the surface speed and position of said feed roller, said feed roller encoder means electrically connected to said microprocessor;
• a second servomotor rotatably mounted to said cutter drum about said cutter drum central axis, said second servomotor driving said cutter drum at variable rates of surface speed throughout a label cutting cycle, said label cutting cycle being a 360.degree. rotation of a single blade cutter drum, said cutter drum rotating at substantially the same surface speed as the feed roller during the interval in the cycle in which said cutter drum is cutting a label, said cutter drum increasing surface speed to rotate at substantially the same surface speed as said vacuum drum during the interval in cycle in which said cutter drum is transferring a cut label to the vacuum drum and slowing down thereafter, such that the average surface speed of said cutter drum over a complete cycle is less than said vacuum drum surface speed but greater than the average feed roller surface speed;
• said second servomotor electrically connected to said microprocessor whereby said microprocessor controls the rotational speed of said second servomotor;
• a cutter drum encoder means for sensing the surface speed and position of said cutter drum, said cutter drum encoder means electrically connected to said microprocessor;
• a third servomotor rotatably mounted to said vacuum drum about said vacuum drum central axis, said third servomotor driving said vacuum drum at a generally constant surface speed;
• and
• a vacuum drum encoder means for sensing the surface speed and position of said vacuum drum, said vacuum drum encoder means electrically connected to said microprocessor.