Ink-jet Head Nozzle Segmentation for Line Darkness and Drying Prevention
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Solution Overview
Problem
Existing image recording apparatuses struggle to record dark straight lines perpendicular to the scanning direction without drying the nozzles, especially when trying to increase recording speed for black-and-white images.
Innovation Solution
The apparatus employs an ink-jet head with black nozzles aligned at a higher density than color nozzles, with specific nozzle group arrangements and jetting patterns to ensure all nozzles have a chance to jet ink frequently, preventing drying and enhancing line visibility by maintaining ink droplet volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If black nozzles are aligned at higher density (smaller intervals) to increase recording speed for black-and-white images, then recording speed is improved, but the dots forming straight lines become smaller and lines are recorded more lightly
Solution Approach 1:
The black nozzles are divided into multiple nozzle groups (first nozzle group, second nozzle group, etc.) that are spatially separated. Each group jets ink at different times during the recording process, allowing the system to maintain high nozzle density while ensuring adequate ink droplet volume through selective activation of subsets of nozzles.
Solution Approach 2:
The recording process is divided into multiple unit recording operations performed in sequence. Each unit operation activates a specific nozzle group, and the groups are activated periodically in rotation. This periodic activation pattern ensures that each nozzle group has sufficient time to maintain ink supply while the overall system achieves high recording speed through parallel nozzle availability.
2Illumination intensity
If black nozzles are aligned at larger intervals (half of color nozzle intervals) to ensure adequate ink droplet volume, then line darkness is improved, but recording speed decreases
Solution Approach 1:
By segmenting the black nozzles into multiple groups with different spatial positions, the system can maintain larger effective intervals within each group (preserving ink droplet volume) while the collective arrangement of all groups provides sufficient nozzle density for high recording speed.
Solution Approach 2:
The solution transitions from a single-dimensional arrangement of nozzles to a multi-dimensional arrangement where nozzle groups are distributed both along the scanning direction and the transport direction. This spatial distribution in multiple dimensions allows the system to achieve both adequate intervals for ink volume and high density for recording speed.
3Productivity
If recording is performed by jetting ink from all black nozzles simultaneously, then recording speed is maximized, but nozzles dry out due to lack of frequent jetting opportunities
Solution Approach 1:
The black nozzles are segmented into multiple groups that are activated in rotation across different unit recording operations. This segmentation ensures that each individual nozzle group has frequent jetting opportunities (maintaining reliability) while the overall system maintains high productivity through the combined capability of all groups.
Solution Approach 2:
The nozzle groups are activated in a periodic rotational pattern, where each group is used repeatedly at regular intervals. This periodic activation ensures that every nozzle group maintains adequate jetting frequency to prevent drying, while the systematic rotation across all groups maximizes overall recording throughput.
4Reliability
If the number of nozzle groups is increased to cover all black nozzles, then all nozzles can jet ink frequently (preventing drying), but the complexity of controlling the recording process increases
Solution Approach 1:
The black nozzles are divided into a practical number of nozzle groups (typically 2-4 groups) that balances comprehensive nozzle utilization with manageable control complexity. Each group is independently controllable, simplifying the activation logic while ensuring all nozzles are used frequently enough to prevent drying.
Solution Approach 2:
The control system implements a simple periodic rotation pattern among the nozzle groups, where groups are activated in a fixed sequence. This periodic control strategy is computationally simple and easy to implement, yet effectively ensures that each nozzle group is used frequently enough to maintain reliability.
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 configuration allows for darker, more visible straight lines in recorded images while preventing nozzle drying, even at increased recording speeds for black-and-white images.
Implementation Method 1
an ink-jet head having a plurality of nozzles and configured to jet the ink droplets from the nozzles
Data Source
AI summary
An image recording apparatus includes an ink-jet head having a plurality of nozzles and configured to jet ink droplets from the nozzles; a carriage configured to carry the ink-jet head, and reciprocate in a predetermined scanning direction; a transport mechanism configured to transport the recording medium, on which the ink droplets jetted from the nozzles land, in a transport direction intersecting the scanning direction; and a control device configured to control the ink-jet head, the carriage and the transport mechanism to perform recording of the image. The nozzles include a plurality of first nozzles which are aligned at first interval with respect to the transport direction and from which first-type ink droplets are jetted, and a plurality of second nozzles which are aligned at second interval with respect to the transport direction and from which second-type ink droplets different from the first-type ink droplets are jetted.