Inkjet Head Unit Nozzle Region Segmentation for Seam Alignment
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Solution Overview
Problem
In inkjet recording devices, the overlapping of head columns in the sub scanning direction leads to color and density unevenness, particularly when the number of colors increases, resulting in a larger device size to mitigate this issue.
Innovation Solution
The implementation of a head unit with pairs of heads that have overlapping nozzle columns divided into distinct nozzle regions, allowing for different discharge positions for each pair, which enables shifting of seam positions without increasing the device size, and ensuring line-symmetrical droplet discharge from heads along the second axis for improved printing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of colors of ink is increased and overlapping portions are provided for each color with shifted seams, then color unevenness and density unevenness are eliminated, but the size of the head unit increases in the sub scanning direction
Solution Approach 1:
The overlapping portion is divided into a plurality of nozzle regions along the sub scanning direction. Each pair of heads uses different nozzle regions for discharge, segmenting the overlapping area to allow multiple color pairs to coexist without seam overlap, thus preventing color unevenness while maintaining compact head unit size
Solution Approach 2:
The patent utilizes the sub scanning direction (second axis) to differentiate nozzle region positions for different color pairs. By assigning different nozzle regions along the sub scanning direction to different color pairs, the patent resolves the contradiction between supporting multiple colors and maintaining compact head unit size
2Manufacturing precision
If pairs of heads are shifted in the sub scanning direction to prevent overlapping of seams, then color unevenness is reduced, but the device size increases
Solution Approach 1:
The overlapping portion is segmented into multiple nozzle regions along the sub scanning direction. Each color pair is assigned to a specific nozzle region, allowing precise control of seam positions without requiring physical shifting of entire head assemblies, thereby maintaining compact device volume
Solution Approach 2:
Different nozzle regions within the overlapping portion are assigned to different color pairs based on their specific discharge requirements. This local differentiation allows each color pair to have optimized seam positioning without affecting other color pairs, achieving precise seam alignment while maintaining compact device size
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 enhances printing quality by minimizing seam overlap and reducing device size, allowing for effective color alignment and improved miniaturization of the recording device.
Implementation Method 1
a head which includes a nozzle column along the first axis... heads discharging droplets of the same color... ink discharged from each nozzle is landed on the recording medium
Data Source
AI summary
A recording device includes, when a transporting direction of a medium is set to a first axis and a direction intersecting with the transporting direction is set to a second axis, a head which includes a nozzle column along the first axis; a pair of heads in which the heads discharging droplets of the same color are paired; and a head unit which includes a plurality of pairs of heads along the second axis. The pair of heads include a predetermined overlapping portion in which the nozzle columns are overlapped with each other in a side view from the second axis, the overlapping portion includes a plurality of nozzle regions divided along the second axis, and a position of the nozzle region which is used in discharge of the droplets is different from a position of the nozzle region of another pair of heads.