Inkjet Ejection Timing for Expansion-Compensated Print Resolution
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Solution Overview
Problem
The expansion and contraction of recording media, such as paper or film, due to ink adhesion, drying, or heat, cause differences in print resolution between upstream and downstream ejectors, leading to deteriorated image quality.
Innovation Solution
An inkjet printing apparatus with multiple ejectors and controllers that estimate and adjust ejection timing based on the expansion and contraction of the recording medium, using encoders and expansion/contraction amount estimators to synchronize ink ejection across different ejectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ejectors are used to print on different portions of the recording medium, then printing efficiency is improved, but differences in print resolution occur due to recording medium expansion and contraction
Solution Approach 1:
The system estimates the expansion or contraction amount of the recording medium before the downstream ejector performs ink ejection. Based on this preliminary estimation, the ejection timing is adjusted in advance to compensate for the dimensional changes, ensuring that ink dots from different ejectors align properly on the expanded or contracted medium.
Solution Approach 2:
The system incorporates an expansion/contraction amount estimator that continuously monitors and estimates the dimensional changes of the recording medium. This estimation feedback is used to dynamically adjust the ejection timing of downstream ejectors, creating a closed-loop control system that maintains print resolution consistency despite medium expansion or contraction.
2Manufacturing precision
If ejection timing is adjusted for downstream ejectors based on expansion/contraction estimation, then print resolution consistency is improved, but device complexity increases
Solution Approach 1:
The expansion/contraction amount estimator acts as an intermediary component that bridges the upstream and downstream ejectors. It processes the dimensional change information and translates it into timing adjustment parameters for the downstream ejector controller, simplifying the overall control architecture while achieving precise resolution consistency.
Data Source
AI summary
A technique is provided that reduces the occurrence of a difference in print resolution between an upstream ejector and a downstream ejector due to expansion and contraction of a recording medium. An inkjet printing apparatus includes four heads arranged in a transport direction and four ejection controllers that control the four heads, respectively. Each ejection controller includes an ejection timing generator that generates an ejection timing signal for causing the head that is controlled to eject ink toward a target portion of a recording medium, an expansion/contraction amount estimator that estimates the amount of expansion and contraction in the target portion, and a correction information generator that outputs, to a downstream ejection controller, correction information that includes the ejection timing signal and expansion/contraction amount information indicating the amount of expansion and contraction.