Digital Filter for Web Meandering Control Noise Attenuation
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Solution Overview
Problem
Existing meandering control devices for inkjet printing apparatuses require a large number of components and time-consuming part selection to set the time constant for filters, which increases complexity and reduces accuracy due to noise components in position signals.
Innovation Solution
A meandering control device incorporating a digital filter to attenuate noise components in position signals, reducing the number of components and simplifying part selection by using a digital filter configuration that includes delayers, adders, and multipliers to set a suitable time constant for effective meandering correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter formed of passive elements (resistor, capacitor, inductor) is used to remove noise from position signals, then noise attenuation is achieved, but the number of parts on the electric circuit increases and part selection becomes time-consuming
Solution Approach 1:
The patent replaces the mechanical/electrical filter system (composed of passive elements like resistors, capacitors, and inductors) with a digital filter implemented in software or firmware. This substitution eliminates the need for multiple physical components while achieving the same noise attenuation function through digital signal processing algorithms.
Solution Approach 2:
The patent changes the approach from selecting physical component values (resistance, capacitance, inductance) to setting digital parameters (filter coefficients, sampling rates) that define the filter characteristics. This allows for easier adjustment and optimization of noise filtering performance without changing the physical hardware configuration.
2Reliability
If a filter formed of passive elements is used to remove noise from position signals, then noise attenuation is achieved, but the time required for selection of parts increases
Solution Approach 1:
The patent replaces the manual selection and assembly of physical filter components with a digital filter implementation where filter characteristics are defined by software parameters. This eliminates the time-consuming process of selecting, testing, and adjusting physical components while maintaining effective noise attenuation.
3Speed
If edge sensor position signals are used directly for meandering correction, then response speed is fast, but accuracy decreases due to noise components
Solution Approach 1:
The patent applies digital filtering to the position signals from the edge sensor, replacing the need for complex analog filtering circuits. The digital filter processes the signals in real-time, maintaining fast response while effectively removing noise components to improve measurement accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the filtered position signals are continuously used to adjust the roller angle for meandering correction. The digital filter provides clean, accurate position information that enables precise feedback control while maintaining responsive correction action.
Data Source
AI summary
A meandering control device includes: a detector configured to detect a position of an edge of a web being conveyed in a width direction of the web; a corrector configured to correct a position of the web being conveyed in the width direction; and a controller including a digital filter configured to perform filtering on a position signal indicating the position of the edge detected by the detector to attenuate a noise component. The controller is configured to drive the corrector to correct the position of the web in the width direction based on the position signal after the filtering.