Print Head Nozzle Group Dot Arrangement Density Correction
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Solution Overview
Problem
Conventional printing technologies face challenges in correcting density variations caused by differences in print characteristics among nozzle groups, leading to degradation in image quality due to visual recognition of differences in dot patterns.
Innovation Solution
A printing apparatus with a print head featuring multiple nozzle groups, each with distinct ejection volumes, uses an arrangement determination unit, size determination unit, and ejection control unit to adjust dot arrangements and sizes based on ejection characteristics, ensuring a consistent print characteristic range and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If print density correction is performed by selecting nozzles to drive based on actual average droplet volume, then print density is corrected, but the dot pattern becomes different from the original, leading to visual recognition of differences and degradation in image quality
Solution Approach 1:
The invention changes the parameter of ink volume per dot by adjusting the number of dots driven from each nozzle group rather than changing which nozzles are driven. By controlling the number of dots (e.g., 1 dot from nozzle group 1, 2 dots from nozzle group 2) to achieve the target average ink volume, the dot pattern arrangement is preserved while correcting density variations through quantitative control of ink deposition.
2Manufacturing precision
If the number of ink dots is adjusted to correct density variations, then print density is corrected, but the position of dots changes, resulting in different dot patterns that are visually detectable
Solution Approach 1:
The invention uses multiple nozzle groups that can reproduce the same dot pattern with different ink volumes. By having nozzle groups 1 and 2 both capable of forming dots at the same positions but with different ejection volumes (2x and 4x respectively), the system can copy the desired dot pattern while adjusting total ink volume through the number of dots driven from each group, maintaining pattern consistency while achieving density correction.
3Manufacturing precision
If significant correction is applied to density variations, then print density is successfully corrected, but the difference in dot pattern becomes visually recognizable, degrading image quality
Solution Approach 1:
The invention applies partial action by using a limited number of nozzle groups (specifically 2 groups with 2x and 4x ejection volumes) to achieve the correction. This partial approach allows density correction to be achieved through moderate adjustments in dot quantity rather than extreme modifications, thereby correcting density variations while keeping the dot pattern changes within imperceptible thresholds and avoiding image quality degradation.
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 corrects density variations while maintaining image quality by adjusting dot arrangements and sizes, reducing the visual detection of differences in print patterns and ensuring a constant ink volume per print pixel.
Implementation Method 1
in the case of a print head employing a piezoelectric element which ejects ink by an applied pressure as a printing element
Data Source
AI summary
A printing apparatus including a print head including nozzle groups each having nozzles, each of the nozzle groups applying ink having a plurality of volumes from the nozzles to form dots including dots differing in size, including: an arrangement determination unit to determine an arrangement of dots to be formed by each of the nozzle groups; a size determination unit to determine sizes of ink ejected to print the dots determined by the arrangement determination unit, according to respective ejection characteristics of the nozzle groups, such that a print characteristic of an image based on the dot arrangement determined by the arrangement determination unit is within a predetermined range; and an ejection control unit to control the print head to eject ink having the plurality of sizes determined by the size determination unit in positions of a print medium based on the arrangement determined by the arrangement determination unit.