Inkjet Conveyance Roller Phase Control for Banding Reduction
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Solution Overview
Problem
The existing multi-pass printing methods using inkjet recording apparatuses often suffer from banding issues due to conveyance accuracy problems, ink characteristics, head variations, and mounting accuracy, which degrade image quality and are difficult to completely eliminate without increasing processing accuracy and costs.
Innovation Solution
A liquid discharge apparatus and method that control the conveyance roller and liquid discharge head to alternately convey the medium and discharge ink in specific patterns, ensuring that the positions of liquid droplets from different nozzles align in the sub-scanning direction, and adjust the phase difference of sine waves generated by the conveyance roller to minimize banding, using a control device to manage the number of nozzles and scanning patterns to maintain image quality without enhancing processing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-pass printing is performed with conventional conveyance control, then productivity is maintained through efficient printing processes, but banding occurs due to conveyance accuracy deviations and landing position variations
Solution Approach 1:
The patent implements dynamic conveyance control by adjusting the conveyance roller's rotation phase and speed based on detected landing position deviations. The system dynamically modifies conveyance parameters between passes to compensate for deviations, ensuring accurate dot placement while maintaining efficient multi-pass printing operations
Solution Approach 2:
The system employs feedback mechanisms by detecting actual landing positions of ink droplets and using this information to adjust conveyance roller parameters for subsequent passes. This closed-loop control ensures that conveyance accuracy is continuously optimized based on actual printing performance, eliminating banding while preserving productivity
2Manufacturing precision
If conveyance roller processing accuracy is enhanced to eliminate banding, then image quality improves through reduced landing position deviations, but production costs increase
Solution Approach 1:
The patent changes operational parameters of the conveyance roller (rotation phase, speed, and timing) rather than modifying the physical precision of the roller itself. By adjusting these controllable parameters dynamically, the system achieves high conveyance accuracy without requiring expensive manufacturing precision improvements
Solution Approach 2:
The system replaces mechanical precision requirements with electronic control mechanisms. Instead of relying on mechanically precise conveyance rollers, the invention uses electronic sensors and controllers to detect and correct landing position deviations, substituting mechanical precision with intelligent control
3Manufacturing precision
If the number of passes is increased to improve image quality, then manufacturing precision improves through better dot placement, but productivity decreases due to longer printing time
Solution Approach 1:
The system performs preliminary detection of landing position deviations before subsequent passes occur. By detecting deviations early and pre-adjusting conveyance parameters, the system ensures accurate dot placement from the beginning of multi-pass printing, eliminating the need for excessive correction passes and maintaining high productivity
Data Source
AI summary
A liquid discharge apparatus includes a conveyance roller, a liquid discharge head, and a control device. The control device controls the head to discharge liquid onto a medium X times in the main scanning direction and Y times in the sub-scanning direction and controls the roller such that a position of a droplet on the medium discharged by an m-th discharge and a position of another droplet on the medium discharged by an (m+Y)-th discharge are same in the sub-scanning direction, where m is an integer not smaller than one and not greater than ((X−1)×Y). Where P is a circumferential length of the roller and L is a difference in a conveyance distance in the sub-scanning direction when the m-th discharge is compared with the (m+Y)-th discharge, the following relation is satisfied:L=(n+(Δθ/2π))×P, where |π−Δθ|<60° and n is an integer.