Web Conveyance Apparatus with Detection Devices for Color Shift Compensation
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately positioning liquid discharge head units to prevent undesired color shift and improve image quality due to web displacement during conveyance, particularly when the displacement occurs in the orthogonal direction.
Innovation Solution
The apparatus incorporates a conveyance apparatus with liquid discharge head units, detection devices, and a controller that adjusts the liquid discharge timing and moves the head units relative to the web to compensate for displacement, ensuring accurate landing positions and reducing color shift by using sensors positioned at specific intervals relative to the conveyance rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid discharge head units discharge liquid onto a to-be-conveyed object at different positions in a conveyance direction, then the liquid discharge can be performed at multiple locations, but web displacement during conveyance causes color shift and positioning accuracy deteriorates
Solution Approach 1:
The patent employs detection devices to detect the actual position of the web during conveyance and feeds this information back to the controller. The controller then adjusts the liquid discharge timing and head unit positioning based on this feedback to compensate for web displacement, ensuring accurate color alignment despite variations in web movement
Solution Approach 2:
The patent makes the liquid discharge system dynamic by allowing the liquid discharge head units to move relative to the web based on detected displacement. The system transitions from a static discharge pattern to a dynamic adjustment mechanism that responds in real-time to web position changes, maintaining accurate liquid application positions
2Measurement precision
If detection devices are positioned close to each other to detect web position accurately, then measurement precision improves, but the system complexity increases
Solution Approach 1:
The patent divides the detection function into multiple separate detection devices positioned at different locations along the conveyance direction. Each device detects web position at its specific location, and the controller integrates this segmented information to determine overall web displacement, achieving accurate measurement without requiring a single complex detection system
Data Source
AI summary
A conveyance apparatus includes a liquid discharge head unit, a conveyance rotator, and a plurality of detection devices. The liquid discharge head unit discharge liquid to an object conveyed in a conveyance direction. The conveyance rotator conveys the object. The plurality of detection devices output a detection result indicating a position of the object. The adjacent two of the plurality of detection devices are spaced at a prescribed distance. The prescribed distance is an integral multiple of a circumference of the conveyance rotator.