Liquid Discharge Head Unit Thermal Layout for Dense Nozzle Drive Circuits
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Solution Overview
Problem
The increasing number of nozzles in liquid discharge apparatuses for high-definition image formation leads to higher current output and heat generation in driving signal output circuits, causing aging deterioration of components and reliability issues, which existing heat management technologies, such as heat sinks and fans, are insufficient to address efficiently.
Innovation Solution
A head unit with a substrate, a driving circuit, and a heat sink, where heat conductive elastic bodies are positioned between the substrate and the heat sink to enhance heat dissipation, including a first integrated circuit, a transistor, and an inductor element, arranged to optimize heat transfer and reduce heat generation without affecting the driving circuit's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of nozzles is increased to achieve high-definition image formation, then the image definition is improved, but the current output and heat generation in the driving signal output circuit increase
Solution Approach 1:
The patent divides the driving signal output circuit into multiple independent amplifier circuits (first amplifier circuit and second amplifier circuit), each handling a subset of nozzles. This segmentation reduces the current burden and heat generation in each individual amplifier circuit while maintaining the overall high-definition image formation capability through coordinated operation of all amplifiers.
2Manufacturing precision
If the number of nozzles is increased to achieve high-definition image formation, then the image definition is improved, but the reliability of the liquid discharge apparatus deteriorates due to component aging
Solution Approach 1:
The patent segments the driving circuit into multiple independent amplifier circuits, which distributes the operational stress and heat generation across multiple components rather than concentrating it in a single circuit. This reduces the aging rate of individual components and improves overall system reliability.
Solution Approach 2:
The patent introduces a switching circuit as an intermediary between the control signal and the amplifier circuits. This switching circuit manages the signal distribution and timing, allowing the system to coordinate multiple amplifiers efficiently while reducing the operational burden on each individual amplifier, thereby reducing component stress and aging.
3Measurement precision
If the operating frequency of the driving signal output circuit is increased to improve driving accuracy of the piezoelectric element, then the waveform accuracy is improved, but the heat generation further increases
Solution Approach 1:
The patent divides the high-frequency driving signal generation into multiple independent amplifier circuits operating at reduced frequencies. Each amplifier handles a portion of the nozzles with lower current demands, achieving the necessary waveform accuracy for high-definition printing without the excessive heat generation that would result from a single high-frequency circuit driving all nozzles.
4Manufacturing precision
If the number of nozzles is increased to achieve high-definition image formation, then the image definition is improved, but it becomes difficult to ensure sufficient region for heat dissipation due to miniaturization
Solution Approach 1:
The patent segments the heat-generating components into multiple distributed amplifier circuits across the substrate. This spatial distribution of heat sources allows for more effective heat dissipation across the available area, as each amplifier generates less heat individually and heat can be dissipated more uniformly across the miniaturized structure.
Solution Approach 2:
The patent utilizes the substrate area in multiple dimensions by distributing amplifier circuits across different regions. This two-dimensional arrangement of heat-generating components optimizes the use of available space for both functional operation and heat dissipation, overcoming the constraints of miniaturization.
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
The solution effectively manages heat dissipation in the driving circuit, improving the reliability and longevity of the liquid discharge apparatus by reducing heat-related stress on components and maintaining high-definition image formation capabilities.
Implementation Method 1
a plurality of heat conductive elastic bodies are positioned between the substrate and the heat sink
Implementation Method 2
a piezoelectric element provided corresponding to each of a plurality of nozzles for discharging the liquid is provided, a predetermined amount of ink is discharged at a predetermined timing from the corresponding nozzle as the piezoelectric element is driven according to a driving signal
Data Source
AI summary
There are provided a substrate on which a first integrated circuit, a first transistor, and a first inductor element are disposed, and which has a first side and a second side facing each other; a heat sink having a fifth side and a sixth side along the first side; the first integrated circuit, the first transistor, and the first inductor element are positioned in order of the first integrated circuit, the first transistor, and the first inductor element from the first side toward the second side, and the heat sink is fixed to the substrate such that a shortest distance between the fifth side and the first side is shorter than a shortest distance between the sixth side and the first side, and a shortest distance between the first integrated circuit and the fifth side is longer than a shortest distance between the first transistor and the sixth side.