Liquid-Ejection Head Unit With Dual Step-Down Voltage Control
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Solution Overview
Problem
Existing liquid ejection apparatuses using piezoelectric elements face a deterioration in ejection accuracy as the apparatus size increases, necessitating improvements in power management and drive signal control.
Innovation Solution
The apparatus incorporates a drive unit with first and second step-down circuits to convert commercial AC voltage to first and second drive voltages, and a drive control circuit to manage these voltages, ensuring precise ejection control through a drive signal output circuit and ejection unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the apparatus size is increased, then the power supply capacity is improved, but the ejection accuracy deteriorates
Solution Approach 1:
The power supply voltage is divided into multiple voltage levels through separate step-down circuits. The first step-down circuit generates a first drive voltage for the output circuit, while the second step-down circuit generates a second drive voltage for the drive control circuit. This segmentation allows independent optimization of power delivery and control precision, resolving the contradiction between power supply capacity and ejection accuracy.
Solution Approach 2:
Different parts of the system are provided with different voltage qualities tailored to their specific needs. The output circuit receives a higher first drive voltage optimized for power delivery to the piezoelectric element, while the drive control circuit receives a lower second drive voltage optimized for precise control operations. This local quality differentiation maintains ejection accuracy while supporting larger apparatus size.
2Power
If the power supply voltage is increased, then the drive power is improved, but the control precision deteriorates
Solution Approach 1:
The power supply system is segmented into two independent voltage generation paths. The first step-down circuit is dedicated to generating high-power first drive voltage for the output circuit, while the second step-down circuit generates low-voltage second drive voltage for the drive control circuit. This segmentation ensures that high drive power and precise control can coexist without interference.
Solution Approach 2:
The second step-down circuit acts as an intermediary between the high-voltage power supply and the drive control circuit. It converts the high power supply voltage into a suitable second drive voltage that provides sufficient control precision while maintaining the ability to drive the high-power first step-down circuit. This intermediary enables both high drive power and precise control.
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
Enhances ejection accuracy and stability by stabilizing power supply voltages and controlling drive signals effectively, maintaining consistent ink ejection across larger apparatus sizes.
Implementation Method 1
The piezoelectric element is provided so as to correspond to each of a plurality of ejection parts in a print head. Further, by the piezoelectric element being driven in accordance with a drive signal, a corresponding amount of liquid to drive of the piezoelectric element is ejected from the ejection part corresponding thereto
Data Source
AI summary
A head unit includes an ejection unit configured to eject a liquid in accordance with a drive signal, and a drive unit supplied with a power supply voltage from outside and configured to output the drive signal, wherein the drive unit includes a first step-down circuit configured to step down the power supply voltage to output a first drive voltage, a second step-down circuit configured to step down the power supply voltage to output a second drive voltage, an output circuit supplied with the first drive voltage and configured to output the drive signal according to the first drive voltage, and a drive control circuit supplied with the second drive voltage and configured to control drive of the output circuit in accordance with the second drive voltage.