Inkjet Print Head Defect Indication Using Visible Test Liquid
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Solution Overview
Problem
Inkjet printers face issues with defective nozzles due to increased ink viscosity, air bubbles, or dust, leading to poor print quality, especially when using transparent or color-matched liquids, making it difficult to identify and address ejection failures visually.
Innovation Solution
A printing device with a print head that includes two types of nozzles: one for a less visible liquid and another for a more visible liquid, allowing for the detection and indication of defective nozzles without a test pattern, using a detection section to identify and print information about defective nozzles with the more visible liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a test pattern is printed using transparent or color-matched liquid, then the actual printing function is maintained, but it becomes difficult to visually identify defective nozzles
Solution Approach 1:
The patent applies color changes by using a visible liquid (different color or higher visibility) specifically for printing test patterns to enable easy visual detection of defective nozzles, while maintaining separate functional nozzle groups for actual printing with transparent or color-matched liquids. This color differentiation resolves the contradiction by making defect detection possible without compromising the actual printing function.
2Difficulty of detecting and measuring
If a visible liquid is used for test pattern printing, then defective nozzles become easy to identify, but it requires additional liquid types and increases device complexity
Solution Approach 1:
The patent applies segmentation by dividing the nozzle array into distinct functional nozzle groups - one group dedicated to printing with visible liquid for test patterns and another group for actual printing with transparent or color-matched liquids. This segmentation allows easy visual detection of defective nozzles while managing device complexity through organized functional separation.
Solution Approach 2:
The patent applies universality by designing the print head to handle multiple liquid types through different nozzle groups, where the system can selectively use visible liquid for detection purposes and transparent/color-matched liquid for actual printing, making the device adaptable to both detection and printing requirements.
3Manufacturing precision
If treatment liquid is used to agglomerate pigments, then printing quality is improved, but the transparent nature of the liquid makes defect detection difficult
Solution Approach 1:
The patent resolves this contradiction by using color changes - the visible liquid used in test pattern printing has distinct color or higher visibility characteristics that enable easy detection of defective nozzles, while the treatment liquid for actual printing remains transparent to maintain pigment agglomeration quality. The separate nozzle groups allow both functions to coexist without interference.
Data Source
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AI summary
A print head (30) has a first nozzle group (NG1) that includes a plurality of first nozzles (NZ1) capable of ejecting a first liquid onto a medium (MEO), and a second nozzle group (NG2) that includes a plurality of second nozzles (NZ2) ejecting a second liquid that is more visible than the first liquid onto the medium. A detection section (U2) is capable of detecting a first defective nozzle (NZ1d), which is ejection failure, from the first nozzle group without printing a test pattern indicating ejection state of each of the first nozzles on the medium. A control section (U1) causes a second nozzle test pattern (TP2) indicating ejection state of each of the second nozzles to be printed on the medium using the second liquid, and information regarding the first defective nozzles detected by the detection section to be printed on the medium using the second liquid.