Segmented Substrate Transport for Precise Lateral Positioning
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Solution Overview
Problem
Conventional vacuum conveyor belts in sheetfed printing systems experience significant lateral movement, leading to imprecise and inaccurate printing due to excessive play, which existing guidance methods fail to adequately address.
Innovation Solution
A transport device with segments connected via joints and a drive system, featuring a pressure system that maintains precise positioning by minimizing transverse movement through segment guide elements and track guide elements, allowing segments to follow a defined path with minimal lateral deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vacuum conveyor belts are used to transport printed sheets, then the sheets can be moved through the printing system, but the conveyor belts exhibit considerable lateral movement resulting in imprecise printing and poor register accuracy
Solution Approach 1:
The conveyor belt is divided into multiple individual segments that can move independently. Each segment is guided separately by guide elements, allowing the belt to accommodate lateral movements while maintaining precise positioning of each segment during printing. This segmentation resolves the contradiction by enabling the belt to be flexible enough to handle lateral shifts yet precise enough for accurate printing.
Solution Approach 2:
Guide elements are introduced as intermediary components between the conveyor belt segments and the printing system. These guide elements actively compensate for lateral movements of the segments, serving as a mediator that maintains precise positioning despite the inherent instability of the conveyor belt. The guide elements translate the unstable motion of the belt into stable, controlled positioning for accurate printing.
2Stability of the object's composition
If side walls are used to guide the conveyor belt along its entire length, then lateral movement is restricted, but a relatively large amount of play must be accepted to prevent tilting and ensure low-wear operation
Solution Approach 1:
Instead of guiding the entire conveyor belt as a single unit with side walls, the belt is segmented into individual sections. Each segment can be guided independently with minimal play, allowing precise positioning during printing while accommodating necessary play for low-wear operation elsewhere in the system. This segmentation enables different parts of the belt to have different guidance requirements.
Solution Approach 2:
The guidance system provides different levels of lateral constraint at different locations along the conveyor belt. In the printing area, segments are precisely guided with minimal play to ensure printing accuracy. In other areas, more play is allowed to prevent tilting and reduce wear. This local differentiation of guidance quality resolves the contradiction between stability and precision.
3Manufacturing precision
If a wedge strip is used to guide the conveyor belt in the center, then lateral positioning is improved, but a relatively low contact force is necessary resulting in certain play perpendicular to the transport direction
Solution Approach 1:
The single central wedge strip guidance is replaced with multiple guide elements distributed across the conveyor belt segments. Each segment has its own guide elements that provide localized lateral positioning with sufficient contact force. This segmentation eliminates the need to choose between low contact force and precise positioning, as each segment can be independently controlled.
Solution Approach 2:
Instead of using a single central guidance point (one-dimensional approach), the system employs multiple guide elements distributed across the width of the conveyor belt (two-dimensional approach). This dimensional expansion allows simultaneous achievement of precise lateral positioning and adequate contact force across multiple points, resolving the contradiction inherent in the single wedge strip approach.
4Manufacturing precision
If segmented deflection rollers with variable diameter are used to adjust bend positions, then positioning precision can be improved, but the system becomes extremely complex and expensive
Solution Approach 1:
The complex system of segmented deflection rollers with variable diameters is replaced by simpler guide elements that work with straight or minimally curved conveyor segments. The segmentation principle is retained for maintaining precision, but the complex deflection mechanism is eliminated in favor of simpler guidance structures that achieve comparable positioning accuracy without the excessive complexity and cost.
Data Source
Figure 1~2a
Figure 2b
Figure 3a
AI summary
The invention relates to a transport device (1) with segments (2) for transporting substrates, wherein in a variant A the segments form a segment traction element (2000) which is driven via a drive element (31) of a drive system (3), or wherein in a variant B the transport device (1) has transverse guides (33) by means of which the segments (2) are movably arranged in a positioning section (101) in a transverse direction (12) relative to one or more traction elements (32), wherein a force (102) is exerted on the segments (2) in the transverse direction (12) by means of a pressure system, such that segment guide elements (211) are pressed against a track guide element (4).so that the segments (2) in the positioning section (101) can each be positioned in the transverse direction (12) independently of the position in the transverse direction (12) of the one or more traction elements (32) and/or the drive element (31) and/or of segments outside the positioning section (101), and/or that the segments (2) in the positioning section (101) have a freedom of movement in the transverse direction (12) that is less than the freedom of movement of the one or more traction elements (32) and/or the drive element (31) and/or the segments (2) outside the positioning section (101). The invention also relates to a pressure device (10) and a use of the transport device (1).