Staggered Edge Delta-Folding for Printed Signatures
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Solution Overview
Problem
Existing printing press technologies face challenges in efficiently cutting and folding printed products, particularly in preventing dog-earing and skewing during delta-folding, as they rely on mechanical tucking and gripping methods that can lead to misalignment and bulkiness, making it difficult to maintain precise folding and prevent inner sheets from being pulled out.
Innovation Solution
An apparatus and method that involves creating staggered edge signatures through perforation and cutting, followed by delta-folding, where lead edge tabs engage perforation slots to secure the fold, minimizing dog-earing and skewing by using a combination of perforation blades, cutting blades, and folding jaws to form precise folds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical tucking and gripping methods are used for delta-folding, then the folding process can be completed, but dog-earing and skewing occur during the process
Solution Approach 1:
The patent applies preliminary action by creating perforation slots and lead edge tabs before the delta-folding process. These pre-formed features guide the folding operation and prevent misalignment, thereby preventing dog-earing and skewing during the actual folding operation.
Solution Approach 2:
The patent introduces perforation slots as an intermediary element that mediates between the cutting process and the folding process. These slots serve as guides that receive the lead edge tabs during folding, ensuring precise alignment and preventing harmful effects like dog-earing and skewing.
2Productivity
If traditional folding methods are used, then the folding operation can be performed, but inner sheets are pulled out and misalignment occurs
Solution Approach 1:
The lead edge tabs act as intermediary elements that engage with the perforation slots during folding. This engagement mechanism reliably holds inner sheets in place during the folding operation, preventing them from being pulled out while maintaining efficient productivity.
Solution Approach 2:
The perforation slots and lead edge tabs are created in advance before folding, establishing a reliable engagement system that ensures inner sheets remain aligned and secured throughout the folding operation, thereby improving both reliability and productivity.
3Productivity
If conventional cutting and folding processes are used, then production can proceed, but bulkiness is created making precise folding difficult
Solution Approach 1:
The perforation slots are created in advance during the cutting process, establishing precise fold lines before the actual folding operation. This preliminary action eliminates bulkiness by creating clean, defined fold lines, enabling precise folding to proceed efficiently without compromising production continuity.
Data Source
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AI summary
An apparatus for cutting and folding printed products is provided. The apparatus (20) includes a perforator (30, 31), a first cutting device (32, 33), creating first slits (142) in the web a second cutting device (34, 35) creating second slits (144) in the web longitudinally offset from the first slits (142) so as to form a signature with a staggered edge (234), and a folder (60) delta- folding the signature so that the staggered edge (234) engages slots (230) in the signature, the slots (230) created by the perforator (30, 31). A method of folding a printed product and a signature are also provided. Lead edges (123) can be more easily prevented from dislodging and dog-earing and skewing can be minimized.