Liquid Discharge Head Unit With Valve Vibration Cleaning
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Solution Overview
Problem
Existing liquid discharge systems face challenges in effectively removing foreign substances from the valve body, leading to nozzle deterioration and unintentional ink discharge due to pressure fluctuations and electrical noise.
Innovation Solution
A head unit with a piezoelectric element that moves a valve body between contact and separated positions to open and close the nozzle, and applies vibration at the separated position to remove foreign substances, combined with a pressure mechanism to control ink discharge and a moving mechanism to avoid unintentional discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve body is kept in contact with the nozzle plate to ensure sealing, then the nozzle sealing performance is improved, but foreign substances accumulate on the valve body surface causing nozzle deterioration
Solution Approach 1:
The patent applies mechanical vibration by driving the valve body coupler at a resonant frequency to vibrate the valve body when it is in the opened state. This vibration causes foreign substances adhering to the valve body surface to detach and be removed, thereby preventing nozzle deterioration while maintaining sealing performance during normal operation.
Solution Approach 2:
The patent implements periodic action by repeatedly opening and closing the valve body through periodic driving of the valve body coupler. This periodic movement, combined with vibration during the opened state, creates a cycle that prevents foreign substance accumulation and maintains reliable sealing over time.
2Reliability
If the valve body is moved to the separated position to remove foreign substances through vibration, then the nozzle reliability is improved, but unintentional ink discharge may occur due to pressure fluctuations
Solution Approach 1:
The patent uses mechanical vibration at resonant frequency to vibrate the valve body in the opened state, which effectively removes foreign substances and improves nozzle reliability without causing unintentional discharge, as the vibration occurs at a controlled frequency that does not trigger unintended ink ejection.
Solution Approach 2:
The patent incorporates feedback control where the driving frequency of the valve body coupler is adjusted based on the operational state. The system monitors the valve body position and adjusts the driving signal accordingly, ensuring vibration occurs only when needed and at appropriate frequencies to prevent unintentional ink discharge while maintaining effective foreign substance removal.
3Productivity
If the valve body coupler is driven at high frequency to vibrate the valve body, then the foreign substance removal effectiveness is improved, but power consumption increases
Solution Approach 1:
The patent optimizes power consumption by driving the valve body coupler at its resonant frequency rather than at arbitrarily high frequencies. This resonant frequency approach achieves effective foreign substance removal with minimal energy input, as the system naturally amplifies the vibration effect at the resonant frequency, reducing the power required from the driver.
Solution Approach 2:
The patent applies parameter changes by adjusting the driving frequency of the valve body coupler based on operational conditions. The system changes the frequency parameter to match the resonant frequency of the valve body, which maximizes vibration effectiveness while minimizing power consumption. This dynamic parameter adjustment ensures efficient foreign substance removal without excessive energy expenditure.
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
Prevents nozzle deterioration by removing foreign substances and ensures reliable ink discharge, reducing ink consumption and unintentional discharge.
Implementation Method 1
a piezoelectric element that moves a valve body between contact and separated positions to open and close the nozzle
Implementation Method 2
applies vibration at the separated position to remove foreign substances
Data Source
AI summary
A head unit includes a liquid discharge head and circuitry. The liquid discharge head includes a nozzle plate having a nozzle, a liquid chamber to store a liquid to be discharged from the nozzle, a valve body in the liquid chamber, a valve body coupler coupled to the valve body, and a driver to drive the valve body coupler to move the valve body. The valve body is movable between a contact position at which the valve body contacts the nozzle plate to close the nozzle and a separated position at which the valve body is separated from the nozzle plate to open the nozzle. The circuitry moves the valve body between the contact position and the separated position to open and close the nozzle in a first operation, and applies vibration to the valve body while the valve body is temporarily held at the separated position in a second operation.