Horizontal form-fill-seal packaging machine and method of controlling the same

In a horizontal form-fill-seal packaging machine including a former for forming a film supplied from a film source into a tubular configuration with lapped side edges extending in a longitudinal direction of the film, conveyor means for conveying articles to be packaged and for feeding articles into the tubular film one after another, a fin sealer for sealing the lapped edges of the tubular film in the longitudinal direction with the articles positioned within the tubular film;

• an end sealer for sealing the tubular film in a crosswise direction thereof in a position between two adjacent articles, and film feeding means for feeding the film supplied from said film source into said end sealer via said former and said fin sealer;
• the improvement comprising:
• a plurality of pushers mounted on said conveyor means and equi-distantly spaced from each other in the feeding direction of the articles, each of said pushers defining the position of a rear end of the article opposite to the feeding direction of the article;
• length detecting means for sequentially detecting the length in the feeding direction of the articles conveyed by said conveyor means;
• and
• control means for controlling said conveyor means and said end sealer in response to the length of each article detected by said length detecting means, said control means controlling the speed of said conveyor means such that an equi-distant space is formed between each two adjacent articles, and controlling the operation timing of said end sealer such that the end sealer seals the tubular film in substantially the central position of said space between two adjacent articles.