Inkjet Driving Circuit Gain Switching for Waveform Accuracy
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Solution Overview
Problem
Ink jet printers face challenges with power consumption and waveform precision in high-speed and high-definition printing, where the number of nozzles increases, leading to deteriorated liquid ejection accuracy and waveform accuracy due to the class D amplification method's limitations.
Innovation Solution
A liquid ejecting apparatus with a comparator, transistor pair, and control signal generating circuit that alternately switches transistors based on voltage comparisons, adjusting output characteristics to improve voltage followability and waveform accuracy, and using capacitors or resistive elements to manage gain during voltage changes and constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the class D amplification method is used to reduce power consumption, then energy efficiency is improved, but waveform precision and liquid ejection accuracy deteriorate when the number of nozzles increases
Solution Approach 1:
The patent implements dynamic switching between linear amplification mode and class D amplification mode based on the operating conditions. The control unit determines whether to use linear amplification (for high precision requirements) or class D amplification (for power efficiency) dynamically, allowing the system to adapt to different operational demands and resolve the contradiction between power consumption and waveform precision
Solution Approach 2:
The patent changes the amplification parameter (gain) dynamically by switching between linear and class D amplification modes. The control unit adjusts the amplification characteristics based on the number of nozzles and required precision, thereby optimizing both power consumption and waveform precision under different operating conditions
2Productivity
If the number of nozzles is increased to meet high-speed and high-definition printing requirements, then productivity is improved, but waveform precision and liquid ejection accuracy deteriorate
Solution Approach 1:
The control unit dynamically selects the amplification mode based on the number of nozzles being operated. When a large number of nozzles are activated simultaneously, the system switches to linear amplification mode to maintain waveform precision despite the increased power consumption, thereby preserving liquid ejection accuracy while supporting high-productivity operations
Solution Approach 2:
The control unit predicts the amplification requirements based on the number of nozzles to be activated and pre-selects the appropriate amplification mode before actual printing occurs. This preliminary action ensures that waveform precision is maintained from the start of high-speed printing operations with multiple nozzles
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 configuration enhances the ejection accuracy and waveform precision of the driving signal, even with a large number of nozzles, by reducing oscillation width and maintaining high waveform accuracy across varying voltage conditions.
Implementation Method 1
a piezoelectric element displaced by being applied with a driving signal, and ejects a liquid from the nozzle by the displacement of the piezoelectric element
Implementation Method 2
a comparator that compares a voltage of an original driving signal with a voltage of a feedback signal
Implementation Method 3
a transistor pair that includes a first transistor having a first gate terminal and a second transistor having a second gate terminal, and outputs the driving signal
Data Source
AI summary
A driving circuit includes a comparator that compares a voltage of an original driving signal with a voltage of a feedback signal of a driving signal, transistors, and a control signal generating circuit that generates a gate signal to the transistor and a gate signal to the transistor. The control signal generating circuit controls to alternately switch on the transistors. Driving abilities of the transistors are switched to be lowered by insertion of capacitors by an adjustment circuit.