Inkjet Printer Dot Size Control via Differentiated Driving Signals
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Solution Overview
Problem
Inkjet printers face challenges in forming dots of desired sizes at high speeds, leading to reduced image quality due to limitations in the waveform of ejection pulses, which can result in increased signal length and decreased image quality when using multiple pulses for dot formation.
Innovation Solution
The inkjet printer employs distinct driving signals for different ejecting parts, allowing for varying numbers of dot sizes across colors, with the first ejecting part forming three sizes and the second forming two, using a combination of ejection pulses and minute pulses to optimize dot formation and reduce signal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple ejection pulses are used to form dots of desired sizes, then dot size control is improved, but the driving signal becomes too long to cope with speed enhancement
Solution Approach 1:
The patent segments the ejection pulses into different types (first type for larger dots, second type for smaller dots) with different pulse widths. By selecting and combining different pulse types, the system can form dots of various sizes while keeping the driving signal length manageable, thus resolving the contradiction between precision and speed.
Solution Approach 2:
The patent dynamically selects which ejection pulses to include in the driving signal based on the required dot size. This dynamic selection allows the system to use fewer pulses for smaller dots and more pulses for larger dots, optimizing the driving signal length for each specific recording task and maintaining high recording speed while achieving precise dot size control.
2Productivity
If the driving signal cycle is shortened for high-speed recording, then recording speed is improved, but the waveform of ejection pulse is limited making it difficult to form dots of desired size
Solution Approach 1:
The patent uses periodic ejection pulses with different pulse widths within each driving signal cycle. By having multiple pulse types available in a short cycle and selecting appropriate combinations, the system maintains high recording speed while achieving precise dot size formation through the periodic variation in pulse characteristics.
3Manufacturing precision
If different numbers of dot sizes are used for different colors, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by allowing different ejecting parts (corresponding to different colors) to have different numbers of dot sizes. For example, the first ejecting part may form three sizes of dots while the second ejecting part forms two sizes. This localized differentiation optimizes image quality for each color channel while managing overall system complexity through a modular approach.
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 enhances image quality by allowing for differentiated dot sizes across colors, improving the recording quality of monochrome and colored images while maintaining a short driving cycle suitable for high-speed single-pass printing.
Implementation Method 1
ejection of droplets is accomplished by input of an ejection pulse to a piezoelectric element provided in the neighborhood of each outlet of the head
Data Source
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AI summary
An inkjet printer (1), comprising: a recording part (2) for ejecting droplets of ink from an outlet toward an object (9), to form dots on said object (9); a moving mechanism (3) for moving said object (9) relatively to said recording part (2) in a moving direction; and a controller (4) for sequentially inputting signals to said recording part (2) said signals being instructions for ejection of droplets, in parallel with movement of said object (9) relative to said recording part (2), wherein said recording part (2) includes: a first ejecting part (23) which ejects ink in a first color and is capable of forming dots of m or more different sizes, m being an integer equal to or more than two; and a second ejecting part (23) which ejects ink in a second color different from said first color, and is capable of forming dots of said m or more different sizes, characterized in that said first ejecting part (23) forms dots of said m different sizes and said second ejecting part (23) forms dots of n different sizes included in said m different sizes, n being an integer equal to or more than one and smaller than m, and a driving signal used for forming a dot of at least one size included in said n sizes by said first ejecting part and a driving signal used for forming a dot of said at least one size by said second ejecting part are different from each other.