Rotary Printing Web Gluing for Waste Reduction
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Solution Overview
Problem
Rotary printing systems generate significant paper waste due to the overfold required for producing printed products with multiple pages, accounting for 2 to 4% of total paper usage, which is not addressed by existing methods.
Innovation Solution
A method involving web-fed rotary printing where partial web strands are glued at the leading and trailing edges, then folded centrally, eliminating the need for overfolds and reducing paper waste by introducing a cross-fold that minimizes trimming waste, using a detection and opening device to manage the signatures for efficient collation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an overfold is created by offsetting the fold line from the center, then signatures can be opened in collating devices, but paper waste increases due to trimming requirements
Solution Approach 1:
The invention extracts and removes the overfold from the signature structure. By applying adhesive at the leading and trailing edges to create a transverse fold exactly at the center, the overfold is eliminated entirely. This allows signatures to be opened in collating devices without requiring the traditional overfold margin, thereby eliminating the paper waste that would otherwise be trimmed away.
Solution Approach 2:
The adhesive is applied at the leading and trailing edges before folding occurs, creating a pre-bonded structure that enables central folding. This preliminary adhesive application allows the fold line to be positioned exactly at the center of the signature without requiring an offset overfold, thus preventing future paper waste while maintaining signature openability.
2Loss of substance
If the fold line is centered between leading and trailing edges, then paper waste is minimized, but signatures cannot be properly opened in collating devices
Solution Approach 1:
Adhesive is applied to the leading and trailing edges before folding, creating a bonded structure that enables the fold line to be positioned exactly at the center. This preliminary bonding action allows central folding while maintaining the structural integrity needed for signatures to be opened in collating devices, thus resolving the contradiction between paper waste minimization and signature openability.
Solution Approach 2:
The invention changes the physical state of the leading and trailing edges by applying adhesive, transforming them from unbonded edges to bonded edges. This parameter change (from unbonded to bonded) enables the fold line to be positioned at the exact center while maintaining the structural properties necessary for signature opening, thus resolving the contradiction between centralized folding and signature openability.
3Loss of substance
If adhesive is applied at leading and trailing edges with central folding, then overfold is eliminated and paper waste reduced, but new gluing process is required
Solution Approach 1:
The invention merges the adhesive application process with the existing printing or finishing processes in the printing press. By integrating the gluing unit into the existing production line and applying adhesive at the leading and trailing edges during the same production cycle, the additional process complexity is minimized while achieving the benefit of overfold elimination and paper waste reduction.
Solution Approach 2:
The system performs the gluing operation automatically as part of the continuous production process, without requiring separate manual intervention. The adhesive application is integrated into the automated production flow, where the gluing unit operates in conjunction with the printing and folding processes, thus minimizing the added complexity while achieving waste reduction.
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
This approach reduces paper waste by eliminating the overfold, resulting in substantial savings of 500 to 1600 tons of paper annually in rotary printing machines, with the central fold minimizing paper usage and maximizing savings.
Implementation Method 1
The method comprises the steps of printing at least two partial web strands (4a, 4b, 4c) of a substrate web (4) in a rotary printing press in successive web sections... applying adhesive in at least one gluing section (18)... overlapping the substrate webs and gluing the two substrate webs in the area of the leading and/or trailing edges
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method for producing a printed product (2) with more than four pages comprises the following process steps: - Printing at least two partial web strands (4a, 4b, 4c) of a substrate web in a rotary printing press in successive web sections of predetermined length, each having a leading edge (6.1) and a trailing edge (6.2), between which an imaginary fold line (24) extending transversely to the web direction runs, - Applying adhesive in at least one adhesive section (18), which is arranged in the area of the leading and/or trailing edge (6.1, 6.2) on one of the mutually facing sides of the at least two partial web strands (4a, 4b, 4c), - Overlapping and gluing the two partial web strands (4a, 4b, 4c) in the area of the leading and/or trailing edges (6.1, 6.2).2), -feeding the glued and superimposed partial web strands (4a, 4b, 4c) to a folding apparatus (8) and cutting the partial web strands (4a, 4b, 4c) along the leading and trailing edges (6.1, 6.2) into signatures (2a) and folding the signatures (2a) along the imaginary fold line (24), -laying out the signatures (2a) and arranging them one above the other in a product storage unit (34), -inserting the stored signatures (2a) into a feeder (42) of a collating device (40) such that the glued leading edges (6.1) or trailing edges (6.2) are aligned.2) are positioned leading in the transport direction (44) of the feeder (42), -capturing the front sides of the signatures (2a) leading in the transport direction of the feeder (42) and having the adhesive section (18) and opening the signatures (2a) by means of a capture and opening device (48) and -feeding the opened signatures (2a) to a conveying element (46) of the gathering device (40).