Perfect-Bound Booklet Binding Method for 180-Degree Spreadability
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Solution Overview
Problem
Perfect-bound booklets face issues with insufficient spreadability and adhesive infiltration, preventing pages from opening fully 180 degrees due to adhesive application methods and kerf slits, which also hinder the ability to neatly cut off leaves from the bottom joint.
Innovation Solution
A binding method involving paper folding, pressing creased parts, applying a flexible first adhesive in the middle area of the rear face, and a high-adhesiveness second adhesive on the entire rear face, allowing for neat cutting of leaves along creases without the signature coming off, while ensuring excellent spreadability and integral fixing of the front and back covers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adhesive is applied on the rear face of the body to fix the back, then the booklet can be opened from its joint, but the rear end part of each sheet bulges upward and sheets do not open substantially 180 degrees
Solution Approach 1:
The adhesive application area is segmented into multiple zones: a first adhesive application area that extends from the rear edge toward the center, and a second adhesive application area adjacent to the first area. This segmentation allows different adhesive properties or amounts in different regions, preventing uniform bulging while maintaining binding strength.
Solution Approach 2:
Different regions of the rear face receive different adhesive treatments. The first adhesive application area may use adhesive with different viscosity, drying time, or bonding strength compared to the second area. This local differentiation ensures that adhesive does not uniformly infiltrate crease portions, allowing pages to open flat while maintaining secure binding.
2Strength
If kerf or slit is provided in the rear part of the body to improve adhesion, then sheets are bonded to the front cover, but adhesive infiltrates through the kerf to bond rear areas of adjacent sheets, preventing 180 degree spread
Solution Approach 1:
The harmful element (kerf or slit that allows adhesive infiltration) is completely removed from the binding structure. Instead of providing penetration paths for adhesive, the invention uses surface-level adhesive application areas that bond sheets to the front cover without creating channels for adhesive to reach rear areas of adjacent sheets.
3Strength
If hot-melt adhesive is applied to attach the front cover, then the front cover is bonded to the body, but the adhesive flows into the joint part and bonds the first sheet, preventing it from opening favorably
Solution Approach 1:
The adhesive application strategy dynamically adapts to the functional requirements of different areas. The first adhesive application area is positioned and sized to provide strong front cover bonding while the second adhesive application area compensates to ensure overall binding strength, allowing the first sheet to open properly while maintaining secure attachment.
4Ease of manufacture
If adhesive is applied in the middle area excluding top and bottom end edges, then leaves can be cut off neatly from the bottom joint, but the top and bottom areas lack adhesive bonding
Solution Approach 1:
The adhesive application is segmented into a first area for neat cutting functionality and a second area for compensatory bonding. The first adhesive application area excludes the top and bottom end edges to allow clean leaf removal, while the second adhesive application area is positioned to provide necessary bonding strength in those end regions.
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 method achieves excellent spreadability and allows for neat cutting of leaves from the bottom joint, maintaining the integrity of the remaining signatures and ensuring the booklet can open fully 180 degrees with continuous printing areas across pages.
Implementation Method 1
a first application step of applying a first adhesive that remains flexible upon curing, in a layer in a middle area excluding each part of 5 to 10 millimeters width from top end edge and bottom end edge of a rear face of the one-book bundle or the multi-book bundle
Implementation Method 2
a second application step of applying a second adhesive in a layer on the entire rear face of the one-book or multi-book bundle including the parts where the first adhesive is not applied
Implementation Method 3
a pressing step of pressing creased parts of the multiple signatures in a thickness direction of the multiple signatures
Data Source
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AI summary
[Problem to be Solved] To provide a binding method of a perfect-bound booklet having excellent spreadability, and in which an arbitrary signature of a body or one or several leaves can be cut off neatly from the bottom of a joint. [Solution] A binding method of a perfect-bound booklet of the present invention includes: a step of folding a sheet to obtain multiple signatures; a step of pressing creased parts of the multiple signatures in a thickness direction of the multiple signatures; a step of jogging a one-book bundle formed of a predetermined number of signatures forming a body, a front cover, and a back cover, or a multi-book bundle formed by stacking a plurality of one-book bundles on top of one another; a step of applying a first adhesive that remains flexible upon curing, in a layer in a middle area 5 to 10 millimeters from both top and bottom ends of a rear face of the one-book bundle or the multi-book bundle; a step of applying a second adhesive on an entire face of the rear face including the parts where the first adhesive is not applied, after leaving the first adhesive layer for a predetermined drying time; and a step of drying and curing the second adhesive for a predetermined drying time.