Machines have been developed in order to apply labels to a moving form web. This is desirable where one wants to apply labels to a large number of articles such as catalogs or other printed forms. Typically, the label is shorter than the form. For example, the form may be eleven inches long and the label two inches long. Accelerating and decelerating the labels to match the form speed allows for continuous label placement on the moving forms. Applying the labels to the forms by hand labor would be time consuming and expensive.
An example of such a device is described in U.S. Pat. No. 4,294,644 to Anderson. This machine uses a motor to pull a label web around a curved edge. The label web includes a series of adhesive labels on a web backing. At the edge, the labels are separated from the backing and applied to a moving form web positioned beneath the curved edge. The device uses sensors to detect a position of a form to receive a label and uses that information to calculate when to apply the label to the moving form web.
The machine described in the '644 patent has limitations, however. For example, there is a limit to the speed at which the motor may pull the label web around the curved edge. Accelerating the label web to match the form web moving at higher speeds may cause the label web to break at the edge due to the increased tension resulting from the higher speed. Therefore, as the speed of the form web increases due to advances in printing technology, this machine will not be able to keep up with those increased speeds. In addition, this machine requires a high degree of accuracy in placing the labels at a particular position onto the moving form web. Since the form web is moving at a high rate of speed, the particular position which is to receive the label is only beneath the curved edge of the machine for a very brief instant. The machine must, therefore, be very accurate when applying the label to the moving form web in order to place the label in a precise position on the form web.
Accordingly, a need exists for an improved apparatus and method for applying labels to moving articles and in particular for increased speed and accuracy for applying the labels. Such an apparatus and method would allow for label application at increased form web speeds, such as from increased printer speeds.