Liquid Ejecting Apparatus Droplet Flight Speed Control
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Solution Overview
Problem
High-speed printing on roll media leads to skewing of ink droplets due to relative movement between the recording head and medium, causing image quality issues, and crosstalk between adjacent nozzles results in uneven ink flight speeds and amounts, compromising image quality.
Innovation Solution
A liquid ejecting apparatus with a driving signal generation unit that generates a leading and a following driving pulse, where the leading pulse sets higher flight speeds for central droplets and the following pulse sets higher flight speeds for end droplets, ensuring combined droplets land in a straight line, reducing skew and crosstalk effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed printing is carried out on roll media, then printing speed is improved, but ink droplets land in skewed positions due to relative movement between recording head and medium
Solution Approach 1:
The patent applies dynamics by differentiating the driving pulse parameters based on nozzle position. Central nozzles receive pulses that produce slower droplets, while end nozzles receive pulses that produce faster droplets. This dynamic adjustment of ejection parameters compensates for the relative movement between recording head and medium, ensuring all droplets land in correct positions even at high printing speeds exceeding 100 m per minute.
2Manufacturing precision
If nozzles are disposed at high densities, then image quality is improved, but crosstalk occurs between adjacent nozzles causing uneven ink flight speeds and amounts
Solution Approach 1:
The patent applies local quality by providing different driving pulse characteristics to different nozzle groups. Central nozzles receive driving pulses with parameters optimized for their position, while end nozzles receive pulses with different parameters. This localized adjustment of ejection parameters compensates for the crosstalk effects that occur at high nozzle densities, ensuring uniform ink flight speeds and amounts across all nozzles.
3Productivity
If multiple inks are ejected simultaneously from adjacent nozzles, then productivity is improved, but crosstalk causes uneven flight speeds and ink amounts
Solution Approach 1:
The patent applies local quality by differentiating the driving pulse parameters for central versus end nozzles. When multiple inks are ejected simultaneously from adjacent nozzles, the central nozzles produce slower droplets while end nozzles produce faster droplets. This localized parameter adjustment ensures that despite the crosstalk from simultaneous ejection, all droplets achieve uniform flight characteristics and land in correct positions.
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 suppresses positional skew and crosstalk, maintaining image quality by ensuring droplets combine and land in a straight line, enhancing the quality of recorded images.
Implementation Method 1
a piezoelectric element 17 that changes volume in response to an applied voltage
Data Source
AI summary
The driving signal generation unit generates a leading driving pulse that is ahead in a unit cycle and a following driving pulse that follows the leading driving pulse; the leading driving pulse is set so that, in the case where liquid droplets are ejected simultaneously from multiple adjacent nozzles, the flight speed of the ejected liquid droplets located toward the central area in a nozzle row direction is higher than the flight speed of the ejected liquid droplets located toward the end areas in the nozzle row direction; and the following driving pulse is set so that, of the liquid droplets simultaneously ejected from the multiple adjacent nozzles, the flight speed of the ejected liquid droplets located toward the end areas is higher than the flight speed of the liquid droplets located toward the central area.