Longitudinal sealing mechanism

Abstract

A longitudinal sealing mechanism is adapted to seal an overlapped portion of a packaging material formed into a tubular shape with the overlapped portion extending along a conveying direction of the packaging material. The longitudinal sealing mechanism includes a contact section, a heating section and a receiving member. The contact section comes into contact with the overlapped portion of the packaging material. The heating section heats the contact section to perform longitudinal sealing of the overlapped portion to form a longitudinal seal portion. The receiving member abuts against the contact section with the overlapped portion of the packaging material being disposed therebetween. The contact section, the heating section, and the receiving member are arranged such that an amount of heat per unit time applied to the packaging material from the contact section decreases in a direction toward both sides of the longitudinal seal portion.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This national phase application claims priority to Japanese Patent Application No. 2006-280335 filed on Oct. 13, 2006. The entire disclosure of Japanese Patent Application No. 2006-280335 are hereby incorporated herein by reference.TECHNICAL FIELD[0002]The present invention relates to a longitudinal sealing mechanism mounted on a bag manufacturing and packaging apparatus and configured to seal an overlapped portion of a packaging material formed in a tubular shape while the packaging material is being conveyed.BACKGROUND ART[0003]In recent years, there has been provided a bag manufacturing and packaging apparatus as a device for bag manufacturing and packaging, which manufactures bags and fills the inside of these bags with articles to be packaged such as snack foods. For example, with a longitudinal bag manufacturing and packaging apparatus called a pillow packaging apparatus, a packaging material that is a sheet-like film is formed into...

AI Technical Summary

Benefits of technology

The present invention provides a longitudinal sealing mechanism for a packaging material that reduces the generation of wrinkles, sealing failure, and other problems along the longitudinal seal portion. The mechanism achieves this by reducing the amount of heat applied to the packaging material in the surrounding area of the seal portion. This is achieved by configuring the contact section, heating section, and receiving member such that the amount of heat per unit time applied to the packaging material decreases in the direction perpendicular to the conveying direction of the packaging material. Additionally, the mechanism includes a receiving member that has a convex contact surface to face the overlapped portion of the packaging material, which prevents direct contact with the heating section and reduces the risk of sealing failure.

Problems solved by technology

However, the above described conventional longitudinal sealing mechanism has the following problems.

Specifically, with the longitudinal sealing mechanism disclosed in the above publication, because a relatively large amount of heat is applied also to the surrounding area of the seal portion, there is a risk that not only the seal portion but also its surrounding becomes contracted, generating wrinkles.

Images