Class D Drive Circuit Placement for Inkjet Carriage
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Solution Overview
Problem
Existing liquid discharge apparatuses face issues with distortion of driving waveforms due to cable noise and increased power consumption, particularly in large format printers, which affect printing quality and durability.
Innovation Solution
A liquid discharge apparatus with a drive circuit mounted close to the carriage support section, utilizing a class D amplifier and a regeneration circuit with a capacitive element or secondary battery to reduce weight, power consumption, and heat generation, while optimizing the placement of discharge sections and supply openings to enhance discharge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the drive circuit is mounted on the carriage to reduce cable length and waveform distortion, then printing quality is improved, but power consumption and heat generation increase due to the need for high current amplification
Solution Approach 1:
The patent changes the amplification mode from class AB to class D, fundamentally altering the operating parameters of the amplification circuit. This parameter change enables the drive circuit to achieve the required voltage amplification with significantly reduced current consumption and heat generation, allowing the drive circuit to be mounted on the carriage without excessive power consumption penalties
Solution Approach 2:
The patent replaces the traditional class AB amplification mechanism with a class D switching amplification mechanism. This substitution uses pulse-width modulation and switching elements instead of linear amplification, dramatically reducing the power consumption and heat generation while maintaining the ability to drive the piezoelectric elements effectively
2Manufacturing precision
If the drive circuit is mounted on the carriage to reduce cable length, then waveform distortion is reduced, but the carriage weight and size increase due to heat sink requirements
Solution Approach 1:
By changing the amplification mode from class AB to class D, the patent fundamentally alters the thermal characteristics of the drive circuit. The class D amplifier generates significantly less heat, eliminating the need for large heat sinks on the carriage, thus keeping the carriage weight and size minimal while maintaining waveform accuracy
Solution Approach 2:
The patent converts the potential harm of heat generation into a benefit by using class D amplification that inherently generates minimal heat. This turns what would have been a problematic thermal issue into a non-issue, allowing the drive circuit to be mounted on the carriage without requiring additional weight for heat dissipation
3Reliability
If class AB amplifier is used to drive piezoelectric elements, then sufficient current is supplied for reliable operation, but power consumption and heat generation become excessive
Solution Approach 1:
The patent replaces the class AB linear amplification system with a class D switching amplification system. This substitution uses pulse-width modulation to control the piezoelectric elements, achieving reliable discharge operation with dramatically reduced power consumption by using switching elements that operate in saturation or cutoff regions rather than linear regions
Solution Approach 2:
The class D amplifier uses periodic pulse-width modulation to drive the piezoelectric elements. By applying periodic voltage pulses with controlled widths rather than continuous analog signals, the system achieves reliable discharge operation while minimizing average power consumption, as the switching elements spend most time in low-power states
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 improves discharge stability by reducing vibration and power consumption, lengthening motor life, and preventing discharge faults due to insufficient ink supply, thereby enhancing printing quality and energy efficiency.
Implementation Method 1
piezoelectric elements are provided to correspond to a plurality of nozzles in a recording head and dots are formed by specific amounts of ink (liquid) being discharged at specific timings from the nozzles due to each of the piezoelectric elements being driven
Implementation Method 2
a drive circuit configured to perform multilevel charging and discharging of the piezoelectric element and to recover and reuse charge which is discharged from the piezoelectric element
Data Source
AI summary
A liquid discharge apparatus has a head provided with discharge sections which discharge a liquid, a drive circuit configured to generate driving signals for driving the discharge sections and discharging the liquid, a carriage mounted with the head and the drive circuit, and a carriage support section configured and arranged to support the carriage. A shortest distance between the carriage support section and the drive circuit is shorter than a shortest distance between the carriage support section and the discharge section which is closest to the carriage support section.