Liquid Ejecting Head Drive Control for Residual Vibration Suppression
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Solution Overview
Problem
Conventional image forming apparatuses using liquid ejecting heads face challenges in effectively suppressing residual vibration when forming a single dot by merging multiple droplets, leading to defects like curved droplets and liquid overflow due to suboptimal timing of residual vibration suppressing pulses, especially at low viscosity and varying environmental conditions.
Innovation Solution
The apparatus employs a head drive controlling unit that outputs driving signals with a first and second driving pulse for droplet ejection and a residual vibration suppressing pulse, timed to match the composite vibration formed by superposition of meniscus vibrations from both pulses, with the pulse width and timing adjusted based on viscosity and temperature to ensure optimal suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional residual vibration suppressing pulse timing is used, then single droplet ejection can be controlled, but multi-pulse droplet ejection produces phase differences causing insufficient vibration suppression
Solution Approach 1:
The patent applies dynamics by making the pulse timing adaptive rather than fixed. The head drive controlling unit dynamically adjusts the timing of the residual vibration suppressing pulse based on the number of driving pulses applied. For multi-pulse driving, the suppressing pulse is output at a timing that accounts for the superposition of vibrations from multiple pulses, thereby adapting the suppression strategy to the specific driving condition and resolving the phase difference problem.
Solution Approach 2:
The patent changes the timing parameter of the residual vibration suppressing pulse based on the driving condition. When multi-pulse driving is detected, the controlling unit modifies the timing parameter to align the suppressing pulse with the composite vibration phase resulting from superposition of multiple pulses. This parameter adjustment ensures effective vibration suppression across different driving modes.
2Adaptability or versatility
If multiple droplets are ejected to form a single dot, then dot formation flexibility is improved, but residual vibration suppression becomes ineffective due to phase differences
Solution Approach 1:
The patent implements feedback by having the head drive controlling unit detect the number of driving pulses applied and use this information to determine the appropriate timing for the residual vibration suppressing pulse. The controlling unit receives feedback about the multi-pulse driving condition and adjusts the suppressing pulse timing accordingly, creating a closed-loop control system that maintains vibration suppression effectiveness regardless of the number of droplets ejected.
Solution Approach 2:
The system dynamically adjusts the suppressing pulse timing based on the actual driving condition. When multiple driving pulses are applied for dot formation, the controlling unit dynamically modifies the timing of the suppressing pulse to match the composite vibration phase, ensuring that vibration suppression remains effective even as the dot formation flexibility is enhanced through multi-pulse operation.
3Manufacturing precision
If residual vibration suppressing pulse timing is optimized for single pulse, then single droplet ejection is accurate, but subsequent droplet ejection suffers from phase differences causing defects
Solution Approach 1:
The patent applies preliminary action by outputting the residual vibration suppressing pulse at an optimized timing before subsequent droplet ejection occurs. The controlling unit calculates and applies the suppressing pulse at a timing that proactively counteracts the composite vibration from multiple pulses, preventing vibration-related defects before they can manifest in subsequent droplet ejection, thus maintaining both single and subsequent droplet accuracy.
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 approach effectively suppresses residual vibration, preventing defects such as curving and overflow during subsequent droplet ejection, even at low viscosity and varying environmental conditions, by aligning the residual vibration suppressing pulse with the composite vibration phase, thereby improving droplet formation accuracy.
Implementation Method 1
a pressure producing unit that produces pressure to pressurize a pressure chamber communicating with the nozzle
Implementation Method 2
The residual vibration suppressing pulse is output at such a timing that the residual vibration suppressing pulse has an opposite phase to a composite vibration Vab that is formed by superposition of a meniscus vibration Va generated by droplet ejection with the first driving pulse and a meniscus vibration Vb generated by droplet ejection with the second driving pulse
Data Source
AI summary
An image forming apparatus includes: a liquid ejecting head including a nozzle that ejects a droplet and a pressure producing unit that produces pressure to pressurize a pressure chamber communicating with the nozzle; and a head drive controlling unit that provides a driving signal to the pressure producing unit. The head drive controlling unit outputs the driving signal including at least a first driving pulse and a second driving pulse to eject droplets and a residual vibration suppressing pulse to suppress residual vibration in the pressure chamber without ejecting a droplet. The residual vibration suppressing pulse is output at such a timing that the residual vibration suppressing pulse has an opposite phase to a composite vibration Vab that is formed by superposition of a meniscus vibration Va generated by droplet ejection with the first driving pulse and a meniscus vibration Vb generated by droplet ejection with the second driving pulse.