Envelope Sheet Sealing with Moisture-Activated Adhesive and Narrow Pressure Rollers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sealed letter producing devices using pressure-sensitive adhesives require robust mechanical structures and are costly due to high pressure requirements, while devices using hot melts are complex and expensive, limiting their installation and maintenance. Additionally, devices with pressure-sensitive adhesives face challenges with paper deformation and breakage when folding multiple sheets.
Innovation Solution
A sealed letter producing device that uses pressure rollers smaller than conventional ones to apply pressure only to the edge portions of the envelope sheet, combined with a moistening section for remoistening paste to develop adhesive strength, allowing for simpler configuration and reduced deformation of paper sheets during the folding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure-sensitive adhesives are used for sealing, then sealing function is achieved, but high pressure is required causing paper deformation and breakage
Solution Approach 1:
The patent changes the adhesive type from pressure-sensitive adhesive to remoistening paste, which activates adhesion through moisture rather than high pressure. This parameter change in the activation mechanism allows effective sealing at lower pressure levels, preventing paper deformation and breakage while maintaining reliable sealing function.
Solution Approach 2:
The patent replaces the mechanical pressure activation system with a chemical/moisture activation system. Instead of relying on mechanical pressure to activate the adhesive, the invention uses moisture-activated remoistening paste, substituting the mechanical activation mechanism with a chemical process that occurs at lower pressures.
2Strength
If hot melts are used for adhesion, then adhesion strength is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the thermal heating system required for hot melt adhesives with a moisture-activation system. This substitution eliminates the need for heating elements, temperature control mechanisms, and associated safety systems, significantly reducing device complexity while maintaining adhesion strength through the remoistening paste mechanism.
Solution Approach 2:
The patent employs a simpler, disposable-like adhesive system (remoistening paste) that does not require complex reusable infrastructure such as heating systems. The moisture-activated adhesive can be applied and activated with simple mechanisms, reducing overall system complexity and cost while achieving the required adhesion strength.
3Device complexity
If pressure rollers are reduced in size, then device complexity is reduced, but pressure application capability is compromised
Solution Approach 1:
The patent changes the adhesive activation parameter from pressure-based to moisture-based. This allows the use of smaller pressure rollers that provide sufficient pressure for sealing without requiring the large, complex roller systems needed for traditional pressure-sensitive adhesives. The moisture activation compensates for the reduced mechanical pressure capability.
Solution Approach 2:
The patent substitutes part of the mechanical pressure system with a moisture activation system. The smaller pressure rollers provide minimal mechanical pressure, while the remoistening paste's moisture activation mechanism provides the primary adhesion force, eliminating the need for large pressure rollers and reducing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves secure sealing with reduced mechanical complexity and cost, minimizing paper deformation and breakage, while enabling easier maintenance and installation, by using smaller pressure rollers and remoistening paste to develop adhesive strength on the envelope sheet.
Implementation Method 1
a moistening section which moistens the remoistening paste provided inwardly of both edge portions in the width direction of the envelope sheet
Data Source
AI summary
In a sealed letter producing device which folds and seals, with a content, an envelope sheet on which pressure-sensitive adhesives are provided, sealing with pressure rollers smaller than in conventional rollers is achieved.Pressure-sensitive adhesives 106 are provided in both edge portions in the width direction of an envelope sheet 100, and remoistening paste 107 is provided inwardly of both edge portions. The remoistening paste is moistened when the envelope sheet wrapping a content is bent and formed into an envelope 50, the entire surface of the envelope is pressurized by low-pressure rollers and adhered with the remoistening paste, and further only both edge portions of the envelope 50 are pressurized by an upper and lower set and a left and right pair of the pressure rollers 80, 80 having a small width to adhere the pressure-sensitive adhesive 106. High pressure required for adhesion of the pressure-sensitive adhesives is only necessary in both edge portions of the envelope, and therefore small pressure rollers 80 will suffice.