Web Movement Sampling With Quadrature Gating to Reduce Maculature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed web movement in printing systems results in significant spoilage due to inertia and uneven acceleration/deceleration, leading to increased maculature during run-up and braking.
Innovation Solution
A device using an incremental encoder to generate phase-offset output signals, a quadrature decoder to produce digital signals for forward and backward motion, and an evaluation circuit with counters and comparators to ensure accurate control signals are generated only when the web is moving forward, preventing unintended backward motion and reducing maculature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the web speed is increased to improve productivity, then the production output increases, but the web movement inertia causes significant speed deviation from the control signal, leading to increased maculature and spoilage
Solution Approach 1:
The patent implements a feedback mechanism where the actual web movement is continuously sampled by an incremental encoder and compared with the control signal. The system detects deviations between commanded and actual movement, and only activates processing operations when the web is moving at the desired speed. This feedback loop prevents processing during acceleration/deceleration phases, reducing maculature while maintaining high productivity.
Solution Approach 2:
The system performs preliminary detection of web movement status before activating processing operations. The incremental encoder continuously monitors web position and speed in advance, and the control system evaluates whether the web is ready for processing before initiating printing or other handling operations. This preliminary action prevents spoilage by ensuring operations only start when web speed is stable.
2Loss of substance
If the web acceleration and deceleration time is extended to reduce speed deviation and maculature, then the spoilage decreases, but the production time increases and productivity decreases
Solution Approach 1:
The feedback mechanism allows the system to maintain high productivity by quickly detecting when web speed stabilizes and immediately activating processing operations. The continuous monitoring enables rapid response to speed changes, minimizing the time the web spends in non-processing states while ensuring no spoilage occurs during acceleration/deceleration.
Solution Approach 2:
The system maintains continuity of useful action by keeping the web moving continuously at high speed while intelligently controlling when processing operations occur. The web never stops moving, but processing is activated only during stable speed phases, maximizing both productivity and quality without requiring extended acceleration/deceleration times.
3Device complexity
If conventional incremental encoders are used to sample web movement, then the device complexity is low, but the measurement precision is insufficient to accurately detect unintended movements during acceleration and deceleration
Solution Approach 1:
The patent employs a feedback-based evaluation circuit that processes encoder signals to detect not only position but also speed and acceleration patterns. This feedback processing enhances the effective measurement precision without requiring a more complex encoder hardware, by intelligently analyzing the timing and pattern of encoder pulses to detect unintended movements.
Solution Approach 2:
The evaluation circuit acts as an intermediary between the simple incremental encoder and the control system. It processes the raw encoder signals, compares actual movement with commanded movement, and generates control decisions. This intermediary layer extracts precise movement information from the simple encoder, achieving high measurement precision without complex encoder hardware.
Data Source
AI summary
In a method or device to sample a web movement, an incremental encoder translates the web movement into two phase-offset output signals. A quadrature decoder generates first and second digital output signals with two respective signal levels. The first output signal is designated as a forward signal and the second output signal is designated as a backward signal. An evaluation circuit outputs a control signal and has a first counter that counts a signal change of the forward signal and subtracts from the count a signal change of the backward signal. A second counter counts a signal change of the control signal. A comparator compares values of the first and the second counters. A disabling device enables the forward signal if values of both the first and second counters are the same so that the forward signal is output, and disables the forward signal if values of the two counters are different.