Inkjet Recording Head Nozzle Frequency Synchronization
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Solution Overview
Problem
Ink-jet printers face issues with banding and unevenness in images due to differences in driving frequencies between overlapping and non-overlapping regions, causing deviations in ink drop amount and landing positions, which affect image quality.
Innovation Solution
An image forming apparatus with a recording head having two groups of nozzles arranged in a specific configuration, where the driving frequencies are controlled to match between overlapping and non-overlapping regions, adjusting the recording density and number of consecutive dots to minimize deviations and banding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recording heads are fixedly arranged along the entire width of the recording medium to enable 1-pass recording, then recording speed is improved, but banding and image unevenness occur due to positional errors at joints of recording heads
Solution Approach 1:
The recording head is divided into multiple nozzle groups (first group and second group) that are arranged in a specific pattern with overlapping regions. This segmentation allows different nozzle groups to cover different areas, and by making the recording head move in the sub scan direction, the system achieves both high-speed 1-pass recording and reduced banding through the overlapping nozzle arrangement that compensates for positional errors at joints.
2Manufacturing precision
If nozzles are overlapped in the overlapping region to reduce banding, then image uniformity is improved, but driving frequencies differ between overlapping and non-overlapping regions causing deviations in ink drop amount and landing positions
Solution Approach 1:
The patent applies different recording strategies to different regions: in non-overlapping regions, single nozzles record dots at normal driving frequency; in overlapping regions, multiple nozzles cooperate with adjusted driving frequencies. The control unit selectively controls the driving frequencies of nozzles in overlapping regions to match the frequencies in non-overlapping regions, ensuring consistent ink drop characteristics across the entire recording medium while maintaining the banding-reducing overlapping structure.
3Measurement precision
If driving frequencies are matched between overlapping and non-overlapping regions, then ink drop consistency is improved, but recording density and dot pattern control become more complex
Solution Approach 1:
The control unit dynamically adjusts the driving frequencies of nozzles based on their location (overlapping vs. non-overlapping regions) and the specific recording requirements. The system can flexibly change driving frequencies, recording densities, and dot patterns in different regions to achieve consistent ink drop characteristics while accommodating the complex overlapping nozzle arrangement. This dynamic control allows the system to maintain simplicity in basic operation while providing advanced control capabilities when needed.
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 reduces banding and image unevenness by ensuring consistent ink drop distribution across the image, improving overall image quality by synchronizing the driving frequencies and adjusting the dot pattern in overlapping regions.
Implementation Method 1
By applying pressure on the ink within the ink chamber depending on image information, ink drops are jetted from the nozzle onto a recording medium
Data Source
AI summary
An image forming apparatus performs a 1-pass recording by a single main scan with respect to a recording medium by a nozzle group including different overlapping nozzles that scan the same overlapping region on the recording medium to record dots. Alternatively, a multi-pass recording is performed by a plurality of main scans with respect to the overlapping region by the same nozzle group or by different nozzle groups. The recording in a central portion of the overlapping region is performed by placing emphasis on the succession or continuity of the dots, while the recording in boundary portions of the overlapping region is performed by placing emphasis on the scattering of the dots.