Sheet Delivery Unit Optical Detection for Skew Correction
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Solution Overview
Problem
Existing sheet-processing machines are inefficient in detecting and correcting skewed or overshooting sheets, leading to machine damage and increased waste due to the inability to differentiate between skewed arcs and overshoots, resulting in reduced effectiveness and increased downtime.
Innovation Solution
A non-contact detection system that monitors the position of sheets downstream of the leading edge stops, allowing for the differentiation between overshoots and skewed sheets, enabling precise alignment and correction without mechanical contact, and triggering appropriate machine functions to prevent accidents and waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical scanning elements are used to detect overshoot sheets, then machine safety is improved, but the system requires safety distance from gripper carriage track and is error-prone
Solution Approach 1:
The patent replaces mechanical scanning elements with optical sensors (photoelectric sensors) to detect overshoot sheets. The optical sensor beam spans the gripper carriage track without requiring physical clearance, eliminating the safety distance problem while maintaining reliable detection capability.
Solution Approach 2:
The patent introduces an intermediary optical sensor system that detects sheet position indirectly through beam interruption rather than direct mechanical contact. This intermediary detection method allows detection without requiring safety distance from moving components.
2Manufacturing precision
If sheet feed is interrupted when side edge position deviates, then alignment precision is improved, but machine effectiveness is reduced due to waste
Solution Approach 1:
The patent segments the detection function into two independent parts: side edge position detection and front edge position detection. Each can be monitored and corrected independently, allowing skewed sheets to be corrected without interrupting the entire sheet feed, thus maintaining machine effectiveness.
Solution Approach 2:
The patent implements feedback control for both side edge and front edge positions. When deviations are detected, the system provides feedback signals to adjust sheet positioning dynamically during the feeding process, enabling correction without interrupting production and avoiding waste.
3Reliability
If mechanical overshoot control is used, then machine protection is improved, but detection accuracy is reduced due to safety distance requirements
Solution Approach 1:
The patent replaces mechanical overshoot control elements with optical sensors that can detect sheet position with high precision without requiring safety distance. The optical detection system provides accurate measurement of overshoot conditions while maintaining machine protection capability.
4Measurement precision
If non-contact detection is used downstream of leading edge stops, then detection accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent uses non-contact optical sensors positioned downstream of the leading edge stops to detect sheet position. This optical detection method provides high measurement precision without mechanical contact, and while it adds some system complexity, it eliminates the need for mechanical scanning mechanisms and safety distances.
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 system effectively reduces machine downtime and waste by accurately detecting skewed or overshooting sheets, ensuring safe operation and efficient processing of various sheet formats, thereby enhancing the overall effectiveness of the sheet-processing machine.
Implementation Method 1
at least one detection unit is provided which monitors the position of the sheets without contact
Data Source
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AI summary
The invention relates to a delivery unit of a sheet-processing machine having a sheet-conveying system that transports sheets to a delivery stack and having a sheet front edge of the sheets at at least two front edge stops. The invention further relates to a method for operating a sheet-processing machine, in which at least one detection unit is provided, which monitors the position of the sheets in a contactless manner, and in which the at least one detection unit is designed to monitor at least one point that is downstream in the sheet transport direction of a stop plane spanned by the at least two front edge stops. The problem addressed by the invention is that of creating a delivery unit of a sheet-processing machine. In particular, the delivery unit is designed in such a manner that damage caused by entrained sheets can be reliably excluded and the efficiency of the machine is increased. According to the invention, the problem is solved in that the at least one monitored point (P) lies within a region (B) that extends 100 mm in the sheet transport direction (15), starting from the stop plane (e).