Simple pressure seal methods

Business forms, particularly mailer type business forms, having pressure sensitive cohesive (such as the type shown in U.S. Pat. Nos. 4,918,128 and 5,427,851 and sold commercially by Toppan Forms Ltd. of Japan under the trade designation TN-124), are becoming increasingly popular because of the significant advantages associated with the use of pressure activated cohesive as opposed to heat activated adhesive or rewettable adhesive. One of many examples of business forms utilizing this pressure activated cohesive is shown in U.S. Pat. No. 5,201.464 (the disclosure of which is hereby incorporated by reference herein). A wide variety of different types of pressure sealing equipment, such as that sold by Moore North America, Inc. under the trademark "SpeediSealer"® has been developed for utilization with such forms, typically such equipment having at leas. two sets of in-line pairs of pressure-seal rollers to apply a sealing force of at least about 100 pounds per lineal inch to effect proper sealing of folded forms, having the cohesive thereon. Much of this equipment is expensive, however, and particularly the pressure-seal rollers themselves can be very expensive. Therefore, there has been a desire to reduce the complexity and expense of such equipment particularly for low or mid-volume installations. A simplified pressure sealing apparatus for acting on business forms having pressure activated cohesive to seal the cohesive has only two or three pressure-seal rollers for effecting proper sealing. The pressure seal rollers may receive a folded business form substantially immediately from the output of a folder, or one of the pressure-seal rollers may function to both assist in folding the form, and then pressure sealing it. The form may be held in a flip plate above the nip between first and second pressure-seal rollers, or a separate set of idler nip wheels may hold the form in position once it has passed completely through the sealing nip. In either case the form may pass completely through the sealing nip yet be moved through the sealing nip in the opposite direction, and then diverted to a stack.