Inkjet Drive Circuit With Overlapping Parallel Coils for Stable Current
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Solution Overview
Problem
The existing liquid ejecting apparatus with a class D amplifier circuit faces challenges in outputting sufficient current while minimizing power consumption and heat generation in the inductor element, leading to unstable operation and potential distortion of the drive signal, which affects the ejection accuracy of the ink.
Innovation Solution
The apparatus incorporates a drive circuit configuration with coils L1 and L2 positioned to overlap in the Z direction on the substrate, allowing their magnetic fluxes to be superposed, and are electrically coupled in parallel within the smoothing circuit to distribute current dispersively, thereby reducing current through each coil and improving waveform accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of current that the drive circuit can output is set to the same level as the amount of current that is supplied to the drive element, then the amount of heat generated by the inductor element is reduced, but the feedback current in the drive circuit decreases and the operation of the drive circuit becomes unstable
Solution Approach 1:
The patent divides the inductor element into two separate inductor elements (first inductor element and second inductor element) that are electrically coupled in parallel. This segmentation allows the drive circuit to output sufficient current while distributing the current flow across multiple inductors, thereby reducing the heat generated by each individual inductor element while maintaining stable operation through adequate feedback current.
2Productivity
If the number of nozzles in the print head is increased to improve print quality and printing speed, then the printing performance is improved, but the amount of current based on the drive signal increases and more heat is generated by the inductor element
Solution Approach 1:
The patent applies segmentation by dividing the inductor element into two parallel-connected inductor elements. This allows the drive circuit to handle the increased current demand from a higher number of nozzles while distributing the thermal load across multiple components, thus enabling improved printing performance without excessive heat generation in a single inductor element.
3Use of energy by moving object
If a class D amplifier circuit is used as the drive circuit, then power consumption is reduced compared to class A, B, or AB amplifier circuits, but when the amount of current increases, the heat generated by the inductor element in the low-pass filter increases
Solution Approach 1:
The patent maintains the power-efficient class D amplifier circuit configuration while addressing the heat generation issue by segmenting the inductor element into two parallel-connected inductors. This combination allows the system to benefit from both the low power consumption of the class D amplifier and the reduced heat generation per inductor element achieved through segmentation.
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 enables the drive circuits to output sufficient current while reducing power consumption and improving the accuracy of the ink ejection by minimizing parasitic impedance and enhancing the cutoff characteristics of the low-pass filter, thus stabilizing the operation and maintaining high ejection accuracy.
Implementation Method 1
coils L1 and L2 positioned to overlap in the Z direction on the substrate, allowing their magnetic fluxes to be superposed
Implementation Method 2
a piezoelectric element such as a piezo element is used... A predetermined amount of ink is ejected from the corresponding nozzle at a predetermined timing by driving each of the piezoelectric elements
Data Source
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AI summary
A liquid ejecting apparatus includes a liquid ejection head, where the liquid ejection head ejects a liquid by a supply of a drive signal to the drive element, and a drive circuit, wherein the drive circuit includes a modulation circuit that modulates a base drive signal, an amplifier circuit that amplifies the modulation signal, a demodulation circuit that demodulates the amplified modulation signal, and a substrate on which the modulation circuit, the amplifier circuit, and the demodulation circuit are provided, wherein the substrate includes a first face and a second face that is the back face of the first face, wherein the demodulation circuit includes a first coil and a second coil electrically coupled in parallel with the first coil, and wherein the first coil is positioned so as to overlap at least part of the second coil in a direction normal to the first face.