Web Position Correction for Liquid Discharge Apparatus
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Solution Overview
Problem
Existing liquid discharge apparatuses face challenges in accurately correcting positional deviations of elongated webs during liquid discharge, particularly due to expansion and contraction, which affects the precision of image formation on continuous sheets under tension.
Innovation Solution
The apparatus includes a conveyor, discharger, first and second movers, and circuitry that control the movement of these components based on position information and expansion-and-contraction range data to adjust the position of image sensors and ink heads, ensuring precise alignment and correction of positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the web is conveyed under tension to maintain stability, then the web position stability is improved, but the web expansion and contraction increases, worsening the position correction accuracy
Solution Approach 1:
The system performs preliminary measurement of the web's expansion and contraction state using the output device before the liquid discharge process. This allows the control unit to pre-calculate compensation values and adjust the discharger position in advance, thereby maintaining position correction accuracy even when the web is under tension and experiencing dimensional changes.
Solution Approach 2:
The control unit continuously monitors the web's position and expansion/contraction state through the output device, comparing actual measurements against target values. Based on this feedback, the system dynamically adjusts the discharger position and liquid discharge timing to compensate for tension-induced dimensional changes, resolving the contradiction between stability and precision.
2Device complexity
If the discharger position is fixed to simplify the structure, then the device complexity is reduced, but the ability to correct web position deviation decreases
Solution Approach 1:
The discharger is transformed from a fixed position to a dynamically adjustable position along the web's width direction. The control unit modifies the discharger's location based on real-time web position deviation measurements, enabling precise liquid discharge even when the web shifts during conveyance under tension.
Solution Approach 2:
The system changes the discharger's positional parameters (location and timing) based on measured web expansion/contraction and position deviation. By adjusting these parameters dynamically, the system achieves high liquid discharge precision without requiring complex mechanical correction mechanisms, thus resolving the contradiction between simplicity and precision.
3Manufacturing precision
If the output device measures web position continuously to improve correction accuracy, then the position correction accuracy is improved, but the measurement time increases, reducing productivity
Solution Approach 1:
Instead of continuous measurement, the output device performs measurements at specific critical points during web conveyance (e.g., at the start and end of the discharge cycle). This partial measurement approach provides sufficient data for accurate position correction while minimizing measurement time and maintaining high web conveyance throughput.
Solution Approach 2:
The control unit maintains continuous calculation and adjustment based on discrete measurements, ensuring that the liquid discharge process remains uninterrupted. By efficiently processing measurement data and immediately applying corrections, the system achieves high position correction accuracy without creating bottlenecks that would reduce productivity.
Data Source
AI summary
A liquid discharge apparatus includes a conveyor, a discharger, a first mover, an output device, a second mover, and circuitry. The conveyor conveys an elongated web in a conveyance direction in a state in which tension is applied to the web. The discharger discharges liquid to the web conveyed by the conveyor. The first mover moves the discharger in a width direction intersecting the conveyance direction. The output device outputs position information of the web in the width direction. The second mover moves the output device in the width direction. The circuitry controls movement of the discharger based on the position information of the web. The circuitry controls movement of the output device based on information of a length of the web in the width direction and expansion-and-contraction range information of the web in the width direction to change a position of the output device in the width direction.