Inkjet Quantization Optimizing Dot Arrangement to Suppress Vibration Irregularities
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Solution Overview
Problem
Existing quantization methods for inkjet printers fail to effectively reduce visibility of vibration irregularities and inter-module joint irregularities across all gradations, and are limited in applicability when nozzles do not overlap in the same area.
Innovation Solution
A quantization method that converts continuous tone images to binary or multivalued images by optimizing dot arrangement timing and frequency for individual pixels, using an error diffusion method or threshold matrix to minimize dispersion and optimize dot patterns based on positional correlations, allowing for reduced visibility of irregularities and increased design freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional quantization methods are used to suppress vibration irregularities, then visibility of density vibration irregularities is reduced in predetermined gradation areas, but graininess deteriorates and the characteristic cannot be satisfied in entire gradations
Solution Approach 1:
The patent applies different quantization control strategies to different gradation regions. Specifically, it optimizes dot arrangement patterns selectively for predetermined gradation areas where vibration irregularities are most visible, while maintaining appropriate graininess characteristics in other gradation regions. This localized optimization resolves the contradiction by addressing vibration suppression needs only where critical, rather than uniformly across all gradations.
Solution Approach 2:
The patent changes quantization parameters (such as dot arrangement frequency, timing, and spatial distribution) based on the specific gradation level and position. By dynamically adjusting these parameters according to local requirements, the system achieves vibration irregularity suppression in critical areas while preserving acceptable graininess characteristics overall, thus resolving the contradiction between these two competing quality attributes.
2Manufacturing precision
If dot distribution and halftone processing are used to solve graininess deterioration at head module joints, then density fluctuation is reduced when nozzles overlap, but the method cannot be applied when nozzles do not overlap in the same area
Solution Approach 1:
The patent develops a quantization optimization method that functions universally across different nozzle configurations. Instead of relying on dot distribution techniques that only work when nozzles overlap, the invention uses position-correlation-based optimization that can handle both overlapping and non-overlapping nozzle arrangements. This universal approach resolves the contradiction by making the solution applicable to diverse printer hardware configurations while maintaining density uniformity at joint areas.
Solution Approach 2:
The patent adjusts quantization parameters based on the actual nozzle arrangement configuration. When nozzles overlap, one set of optimization parameters is applied; when they don't overlap, different parameters are used. This adaptive parameter adjustment allows the system to maintain low density fluctuation across joint areas regardless of the specific nozzle configuration, thus achieving both density precision and configurational versatility.
3Object-affected harmful factors
If halftone pattern control is used to suppress irregularities from relative vibrations, then belt-like irregularities are effectively suppressed in paper feed direction, but the method increases device complexity
Solution Approach 1:
The patent replaces complex mechanical halftone pattern control mechanisms with a computational quantization optimization approach. Instead of using mechanical means to physically control halftone patterns, the invention uses digital image processing techniques that analyze position correlations and optimize dot arrangements algorithmically. This substitution resolves the contradiction by achieving the same vibration irregularity suppression effect through software-based quantization optimization rather than complex mechanical control systems.
Data Source
AI summary
A quantization method includes: quantizing first image data, and converting the first image data to second image data that indicates a binary or multivalued quantized pattern with a smaller number of gradations than that of the first image data, for which dots are arranged by the same recording element for individual pixels of a pixel column along a first direction respectively and dots are arranged at a plurality of different timings for individual pixels of a pixel column along a second direction orthogonal to the first direction; and optimizing the quantization in at least some gradations, and reducing dispersion of a generation frequency of a dot arrangement for each relative positional relation between a pixel of interest in the case that individual pixels within the quantized pattern are successively defined as the pixel of interest and a plurality of vicinity pixels positioned in the vicinity of the pixel of interest.