Inkjet Nozzle Inspection Using Variable Dot Size Test Patterns
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Solution Overview
Problem
Existing inkjet printing technologies face challenges in accurately inspecting nozzle abnormalities due to reduced density differences in test patterns printed with small dots, leading to inadequate reading and inspection results.
Innovation Solution
A printing apparatus and method that utilizes a printing head capable of discharging dots of two sizes, where the control unit prints a test pattern with a greater number of smaller dots than larger dots, enhancing the density and inspection accuracy of ink discharge states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a test pattern is printed using small dots, then the printing resolution is improved, but the density difference with the printing medium is reduced making reading and inspection difficult
Solution Approach 1:
The test pattern is segmented into multiple types (first test pattern with large dots, second test pattern with small dots, third test pattern with medium dots) rather than using a single uniform dot size. This segmentation allows each pattern type to serve different inspection purposes, with larger dots providing better density contrast for reading and smaller dots providing higher printing resolution for detailed nozzle inspection.
Solution Approach 2:
Different regions of the test pattern have different dot sizes and densities tailored to specific inspection needs. The first test pattern uses large dots for areas requiring high density difference, while the second test pattern uses small dots for areas requiring fine detail inspection. This local differentiation of quality ensures optimal performance for various inspection scenarios.
2Measurement precision
If the number of small dots is increased to improve inspection accuracy, then the density of the test pattern is improved, but the reading difficulty on bright printing media increases
Solution Approach 1:
The test pattern is divided into multiple segments with different dot sizes. The first test pattern with large dots provides high readability on bright media, while the second test pattern with small dots provides high inspection accuracy. By segmenting the test pattern into multiple types, the invention resolves the conflict between readability and inspection accuracy.
Solution Approach 2:
The dot size parameter is varied across different test patterns. The first test pattern uses larger dot sizes for better visibility and readability, while the second test pattern uses smaller dot sizes for higher inspection accuracy. This parameter change allows the system to optimize for different inspection requirements.
Data Source
AI summary
A printing apparatus includes a printing head including a nozzle configured to discharge a dot of a first size and a dot of a second size smaller than the first size, the dots being ink dots, and a control unit configured to control the printing head to print, on a printing medium, a test pattern for inspecting a state of ink discharge by the nozzle. The test pattern includes a first pattern element formed by a plurality of the dots of the first size and a second pattern element formed by a plurality of the dots of the second size. The control unit causes the printing head to print the test pattern where a number of the dots of the second size forming the second pattern element is greater than a number of the dots of the first size forming the first pattern element.