Multi-Printhead Die Ink Drop Alignment via Encoder Phase Adjustment
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Solution Overview
Problem
Inkjet printers with multiple printhead dies face challenges in aligning ink drops due to non-uniform nozzle spacing and media variations, such as stretch or shrinkage, which affect print quality and resolution.
Innovation Solution
A system that uses an encoder signal up-sampling technique to align firing pulses between printhead dies to sub-pixel accuracy by adjusting the phase of the up-sampled encoder signal, allowing for precise alignment of ink drops across the media, even with varying media conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple printhead dies are used to print multiple colors, then printing productivity is improved, but alignment precision between ink drops deteriorates due to non-uniform nozzle spacing and media variations
Solution Approach 1:
The system measures the actual position of ink drops from multiple printhead dies and uses this feedback to calculate and apply compensation values to the encoder signal, dynamically adjusting the firing timing to correct alignment errors caused by non-uniform nozzle spacing and media variations
Solution Approach 2:
The invention modifies the encoder signal parameters (phase and timing) based on measured print offsets, transforming the fixed timing signal into a dynamically adjusted signal that compensates for alignment errors and maintains precise ink drop positioning across multiple printhead dies
2Manufacturing precision
If encoder signal up-sampling is applied to achieve sub-pixel accuracy, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary measurement of print offsets during a calibration phase and pre-calculates compensation values that are stored and applied during actual printing operations, avoiding the need for complex real-time calculations and reducing operational complexity
Solution Approach 2:
The invention replaces complex mechanical alignment adjustment mechanisms with an electronic signal processing approach, using software-based phase adjustment of the encoder signal to achieve precise alignment without additional mechanical complexity
Data Source
AI summary
A method and apparatus for printing is disclosed. The printing is done with multiple printhead dies. The nozzles in the different printhead dies are fired using different phases in an up-sampled encoder signal. The different phases correspond to a print offset between the different printhead dies.