Threshold Matrix Generation for High-Speed Inkjet Dot Placement
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Solution Overview
Problem
Inkjet-type image recording technologies face issues with unintended deviation of writing dots during high-speed image recording, leading to poor image quality due to the expansion of halftone dot images in the width direction.
Innovation Solution
A threshold matrix generation method that sets writing elements at specific intervals in a matrix space, allocating turn-on numbers based on distance from determined elements to ensure precise dot placement, and optionally shrinking the matrix in the row direction for high-speed operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the image is recorded by performing halftoning on the image shrunken to a half in the width direction and extending the thus-obtained halftone dot image in the width direction, then high-speed image recording is achieved, but unintended deviation of writing dots occurs
Solution Approach 1:
The patent divides the matrix elements into writing elements and non-writing elements, with writing elements positioned at specific intervals (every N-1 elements) to correspond to actual writing positions during N-fold speed recording. This segmentation prevents dot deviation by ensuring that halftoning is performed only at positions where dots will be written, while non-writing elements are excluded from the halftoning process.
2Productivity
If writing elements are positioned at intervals of (N-1) matrix elements in the column direction for N-fold speed recording, then high-speed recording is enabled, but dot deviation occurs due to improper threshold matrix configuration
Solution Approach 1:
The patent applies different properties to different parts of the matrix: writing elements are assigned threshold values for halftoning operations, while non-writing elements are excluded from halftoning. This local differentiation ensures that the threshold matrix configuration is optimized for the specific N-fold speed recording pattern, preventing dot deviation by treating writing and non-writing positions differently.
Data Source
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AI summary
An image obtained by shrinking an original image in a row direction is halftoned, and this halftone dot image is enlarged in the row direction and recorded at double speed. In order to determine a threshold value of a threshold matrix used for halftoning an image, prepared is a matrix space in accordance with writing positions used for actual recording of an image. In the matrix space, writing elements are set alternately with non-writing elements both in the row direction and in a column direction. In the matrix space, turn-on numbers are allocated to all the writing elements in avoidance of the non-writing elements. Then, in accordance with the turn-on numbers, respective threshold values for the writing elements are determined. By shrinking the threshold matrix in the row direction with omission of the non-writing elements, a threshold matrix for double speed is obtained.