Sheet Folding Mechanism with Compressed Air and Braking
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Solution Overview
Problem
Existing methods for processing printed sheets from digital printing machines face challenges in reducing transport speed while maintaining high performance and avoiding quality issues and blank pages, particularly when handling consecutive sheets with different formats and properties.
Innovation Solution
A device with a mechanical braking element, a stationary folding knife with compressed air, and a folding table that collects sheets to form a stack, allowing for controlled folding and reduced transport speed, along with sensors for precise control and adjustment to prevent collisions and ensure proper alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If transport speed is reduced to enable gentle processing of printed sheets, then processing quality improves, but productivity decreases
Solution Approach 1:
The folding blade performs folding action in advance before the sheets reach the transport line, allowing high-speed folding without affecting subsequent gentle transport and processing quality
Solution Approach 2:
The processing system is segmented into high-speed folding section and gentle transport section, allowing different speed requirements to be met in different stages of the process
2Manufacturing precision
If folding is performed to enable gentler processing, then processing quality improves, but the number of blank pages increases
Solution Approach 1:
The system dynamically adjusts the folding pattern based on the specific production order and sheet characteristics, optimizing the folding arrangement to minimize blank pages while ensuring gentle processing
3Productivity
If high transport speed is used to maintain productivity, then productivity is maintained, but gentle processing becomes difficult and quality problems occur
Solution Approach 1:
All high-speed processing actions are performed in advance before sheets enter the gentle transport zone, allowing productivity to be maintained without compromising quality in the final processing stages
Solution Approach 2:
The system separates high-speed folding operations from gentle transport operations, allowing each to be optimized independently for their respective requirements
4Ease of operation
If gaps are created between printed sheets to accommodate finishing equipment, then processing is enabled, but transport speed must increase
Solution Approach 1:
Folding is performed in advance before sheets need to be separated for finishing equipment, allowing continuous high-speed transport without requiring speed reduction for gap creation
Data Source
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AI summary
The invention relates to a device and a method for further processing successive, sequentially printed sheets (21...n), comprising a conveyor (3), a folding table (6), a folding blade (7), a pair of folding rollers (8), at least one hold-down device (29), and a machine control (35) operatively connected to the folding blade (6) and the hold-down device (29). The hold-down device (29) has at least one mechanical braking element (34) acting on the top surface (21"'...n"') of the printed sheet (21...n) to be positioned on the folding table (6), acting in the region of the trailing edge (21"...n"). The stationary folding blade (7) has a compressed air device (15) connected to a first compressed air source (14) and has at least one outlet opening (18) for compressed air (16) directed towards the folding roller gap (25). The folding table (6) forms a gathering unit (6') for at least two consecutive printed sheets (21...n).In the area of the conveyor (3) a sensor (38) connected to the machine control (35) is arranged to detect the printed sheets (21...n) transported by the conveyor (3).