Curl in a web may be caused by any one or more of several factors. In a printing operation, a strip of paper or the like is unwound from a roll thereof and forms a continuous web. Frequently such a web has a curl therein as it is unwound from the roll thereof.
Numerous types of printing apparatus print upon a continuous web or strip. During the printing process a web may be caused to curl.
When curl occurs, problems exist.
For example, curl in the web usually results in curl in individual sheets which are severed from the web following a printing operation. Other problems may occur in the web prior to severance thereof into individual sheets, if curl is permitted to remain in the web.
Several types of mechanisms have been employed to remove curl in a continuous web. However, none of the mechanisms designed to solve the curl problem have been completely satisfactory. Most known types of decurler mechanisms do not have adjustment capability and are therefore not capable of proper removal of curl regardless of the degree thereof.
Other known decurler devices, in an attempt to remove curl regardless of the degree thereof, sometimes scratch the web.
Another problem exists in that webs used in a printing process may be of any one of numerous thicknesses or weights or have various degrees of rigidity or flexibility.
Other problems which occur in known decurler mechanism include that in which a decurler mechanism causes wrinkle in a web.
Another problem which exists in most known decurler mechanisms is that such mechanisms are capable of removal of curl in a web only if the curl exists in a given direction in a web.
A suitable decurler is one which is capable of removing curl in a web regardless of the type or nature of the web and the degree and direction of curl therein.