Ink Jet Printer Drop Size Control via Feedback
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Solution Overview
Problem
Ink jet printers face challenges in maintaining consistent ink drop size over time due to changes in printhead characteristics, leading to variations in image quality.
Innovation Solution
A printer controller determines the actual ink drop size by counting the number of ink drops and measuring ink flow, then adjusts activation signals to ink drop ejectors to ensure drops meet predetermined size criteria, using specialized detectors and sensing features on solid ink sticks to track ink consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the printhead is used over time, then the ink jet printer can produce more images, but the ink drop size changes due to printhead characteristic changes
Solution Approach 1:
The system measures the actual ink drop size using a detector and compares it to the target drop size. Based on this feedback, the controller adjusts the activation signal parameters (voltage, pulse width) to compensate for printhead degradation and maintain consistent ink drop size over time.
Solution Approach 2:
The system dynamically changes the activation signal parameters (voltage magnitude, pulse duration) in response to measured ink drop size variations. By adjusting these parameters, the system compensates for printhead characteristic changes and maintains consistent printing performance.
2Manufacturing precision
If the activation signal is increased to compensate for printhead degradation, then ink drop size can be maintained, but energy consumption increases
Solution Approach 1:
Instead of uniformly increasing activation signals for all nozzles, the system applies targeted adjustments only to nozzles that exhibit deviation from target drop size. This partial action approach maintains precision while minimizing unnecessary energy consumption in properly functioning nozzles.
Solution Approach 2:
The activation signal parameters are dynamically adjusted based on real-time measurements of actual ink drop size. The system transitions from static, predetermined signals to dynamic, adaptive signals that optimize energy consumption while maintaining drop size consistency.
3Manufacturing precision
If an algorithm is used to adjust activation signals based on time and temperature history, then ink drop size consistency can be maintained, but device complexity increases
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by measuring its own output (ink drop size) and automatically modifying its operation (activation signals) to maintain performance. This eliminates the need for external calibration equipment or complex manual adjustment mechanisms.
Solution Approach 2:
The system performs preliminary measurements of ink drop size under various conditions (time, temperature) to establish baseline characteristics. This preliminary data is used to pre-calculate compensation parameters that simplify real-time control decisions.
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
This method ensures consistent ink drop size, maintaining image quality by compensating for changes in printhead characteristics and ink consumption, thereby improving print consistency.
Implementation Method 1
the ink drop ejectors are thermal ejectors that heat ink in the conduit to boil the ink and form a gas bubble behind the drop of ink to be ejected
Implementation Method 2
the ink drop ejectors are piezo-electric ejectors that line the ink conduit near the orifice. The piezo-electric ejectors change shape in response to an electrical activation signal
Data Source
AI summary
An ink jet printer includes an ink supply system and a printhead with nozzles for ejecting ink drops. The printer determines the average size of the ejected ink drops by comparing the number of ink drops ejected in a predetermined time with the quantity of ink delivered through the printers ink supply system during that time. If the determined average ink drop size does not match predetermined ink drop size criteria, the printer adjusts the activation signals for the ink jet nozzles to alter the ink drop size. A solid ink printer determines the quantity of ink delivered through the ink supply system by counting the number of whole or partial ink sticks that pass a predetermined point in the ink supply system. The counter detects a sensing element formed on an external surface of the ink stick. Exemplary detectors include a mechanical arm, or a thermistor to detect a change in the printer melt plate temperature due to a change in the cross sectional area of an ink stick being melted.