Liquid Jet Head Pulse Control for Stable High-Viscosity Ejection
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Solution Overview
Problem
Existing liquid jet recording apparatuses face challenges in maintaining stable ejection of liquids, particularly those with high viscosity, due to fluctuations in ejection speed and heat generation, leading to instability and increased complexity.
Innovation Solution
Incorporating ejection pulses and heat generation pulses in the drive signal to control heat generation, with specific control methods such as adjusting pulse count and thermal distribution, ensuring stable ejection even with high viscosity liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the jet unit is driven continuously to maintain ejection, then the ejection speed can be maintained, but heat generation increases causing ejection instability
Solution Approach 1:
The drive signal is designed with periodic pulses including both ejection pulses (for liquid ejection) and heat generation pulses (for heating without ejection). This periodic action allows the system to alternate between ejection phases and heating phases, preventing excessive heat accumulation while maintaining ejection capability. The ejection pulses have widths in a range where liquid is ejected, while heat generation pulses have widths in a range where liquid is not ejected, enabling independent control of ejection and heating functions.
2Reliability
If the drive frequency is increased to improve ejection stability, then ejection consistency improves, but heat generation increases causing viscosity changes
Solution Approach 1:
By implementing periodic ejection pulses and heat generation pulses in the drive signal, the system can control the average heat generation while maintaining ejection stability. The ejection pulses occur at frequencies that ensure stable ejection, while interspersed heat generation pulses provide controlled heating without causing excessive temperature rise that would change liquid viscosity.
Solution Approach 2:
The system changes the parameters of the drive signal, specifically the pulse widths of ejection pulses and heat generation pulses. By adjusting these pulse widths within specific ranges, the system optimizes the balance between ejection stability and heat generation control, preventing viscosity changes that would affect ejection performance.
3Ease of operation
If heating is applied to reduce liquid viscosity for easier ejection, then ejection becomes easier, but excessive heat causes ejection instability
Solution Approach 1:
The periodic alternation between ejection pulses and heat generation pulses ensures that heating is applied only when needed to reduce viscosity, rather than continuously. This prevents excessive heat accumulation that would cause ejection instability, while still providing sufficient heating to maintain ease of ejection for high viscosity liquids.
Solution Approach 2:
The heat generation pulses maintain a continuous heating effect over time by being periodically applied, ensuring that the liquid remains at an optimal temperature for ejection without requiring continuous high-power heating that would cause instability.
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
Stabilizes ejection characteristics by controlling heat generation, allowing for consistent ejection of high viscosity liquids and reducing fluctuations in ejection speed, thereby improving overall ejection stability.
Implementation Method 1
one heat generation pulse or a plurality of heat generation pulses which has a pulse width in a range in which the liquid is not ejected from the nozzle, and which controls a heat generation amount generated when the jet unit is driven
Data Source
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AI summary
A liquid jet head and so on capable of easily improving ejection stability of a liquid are provided. A liquid jet head (4) includes a jet unit (41, 42, 43) including a plurality of nozzles (Hn) configured to jet a liquid (9) and a plurality of pressure chambers (C1e, C2e) communicated individually with the nozzles, and each filled with the liquid, and a drive unit (49) configured to drive the jet unit based on a drive signal (Vd) having a plurality of pulses (P) in a predetermined print period (Tp) to thereby jet the liquid which fills an inside of the pressure chamber from the nozzle. The plurality of pulses in the drive signal includes one ejection pulse or a plurality of ejection pulses (Pj) having a pulse width in a range in which the liquid is ejected from the nozzle, and one heat generation pulse or a plurality of heat generation pulses (Ph) which has a pulse width in a range in which the liquid is not ejected from the nozzle, and which is configured to control a heat generation amount generated when the jet unit is driven.