Inkjet Printer Printhead Load Balancing for Streak Reduction
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Solution Overview
Problem
Inkjet printers face issues with streakiness due to cross-process direction errors, where inkjets eject ink drops along deviating paths, leading to reduced image quality, and this problem worsens with increased ink throughput.
Innovation Solution
A color inkjet printer system that includes a media transport, an image sensor, and a controller to identify and redistribute inkjet operations from overworked printheads to underworked ones, using test patterns to assess and adjust the printing process, thereby reducing cross-process direction errors and streakiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink throughput through an inkjet is increased to improve productivity, then printing speed and output are improved, but the likelihood of cross-process direction error and streakiness increases
Solution Approach 1:
The system dynamically adjusts the operational load of individual inkjets based on real-time performance monitoring. The controller continuously tracks cross-process direction errors for each inkjet and redistributes printing operations to maintain optimal performance across all inkjets, allowing the system to adapt to changing conditions as ink throughput increases.
Solution Approach 2:
The system changes the operational parameters of individual inkjets by redistributing print jobs between them. When an inkjet exhibits cross-process direction error, the controller modifies the workload distribution by assigning fewer operations to that inkjet and more to neighboring inkjets, thereby maintaining print quality at higher throughput levels.
2Productivity
If the number of inkjet operations per inkjet is increased to improve productivity, then printing efficiency is improved, but the onset of cross-process direction error occurs earlier
Solution Approach 1:
The system implements continuous feedback monitoring of each inkjet's performance through test patterns and image sensor analysis. The controller uses this feedback to detect early signs of cross-process direction error and adjusts the operational load of individual inkjets accordingly, preventing reliability degradation while maintaining high overall productivity.
Solution Approach 2:
The workload distribution among inkjets is dynamically adjusted based on real-time performance data. The system transitions from static load assignment to dynamic load balancing, where inkjets that maintain stability can handle more operations while those showing early signs of error are relieved of workload, extending the reliable operation period.
3Productivity
If inkjets operate continuously with high load to maintain productivity, then output is maintained, but streakiness and cross-process direction errors increase
Solution Approach 1:
The system identifies and temporarily reduces the load on inkjets that are developing cross-process direction errors, allowing them to 'recover' by operating at lower stress levels. This selective load management prevents the propagation of errors while maintaining high output through redistribution to healthier inkjets.
Solution Approach 2:
The system dynamically balances the workload across the inkjet array based on real-time performance monitoring. By continuously adjusting which inkjets handle which print operations, the system maintains high overall output while preventing any single inkjet from exceeding its stable operational capacity, thereby maintaining print quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces the likelihood of cross-process direction errors and streakiness by redistributing inkjet operations, delaying the onset of errors and reducing printhead maintenance, thus improving image quality and operational efficiency.
Implementation Method 1
The actuators in the printheads respond to the firing signals by expanding into an ink chamber to eject ink drops
Implementation Method 2
Each inkjet has a thermal or piezoelectric actuator that is coupled to a printhead controller
Data Source
AI summary
A method of operating a printer distributes inkjet operations from frequently used inkjets to lesser used inkjets. The redistribution of the inkjet operations helps reduce the number of inkjets exhibiting cross-process direction error so printhead maintenance operations, such as purging, occur less frequently.