Invisible Ink Nozzle Defect Marking for Print Media
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Solution Overview
Problem
Existing printing technologies often require printing marks or position markers on the medium, which can limit the usability of the printed result as a product and consume a portion of the medium for inspection purposes.
Innovation Solution
A printing apparatus and method that utilize a first printing unit with multiple nozzles for ink ejection and a second printing unit for special liquid printing. The special liquid is rendered invisible over time or in specific environments, allowing for the printing of a specific mark in frames where defective nozzles were used, without affecting the usability of the printed medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mark or position marker is printed on the medium to identify defective nozzles, then the occurrence of defective nozzles can be identified, but the usability of the printed result as a product is limited and a portion of the medium is consumed for inspection purposes
Solution Approach 1:
The patent uses invisible ink that changes color or becomes visible under specific conditions (such as UV light irradiation) to print inspection marks. This allows the mark to be invisible under normal conditions, preserving the usability of the printed medium as a product, while becoming visible when needed for inspection to identify defective nozzle occurrences.
Solution Approach 2:
The patent changes the physical or chemical parameters of the ink by using special invisible ink that responds to environmental conditions (such as UV light, temperature, or time). This allows the inspection mark to be hidden under normal conditions and revealed only when specific parameters change, thus maintaining both defective nozzle identification capability and product usability.
2Reliability
If a position marker is printed on the medium for inspection purposes, then the inspection process can be performed, but the entire medium cannot be used as a product and a portion is consumed for inspection
Solution Approach 1:
The inspection mark is printed using invisible ink that remains invisible under normal conditions, allowing the entire medium to be used as a product without visible markers. When inspection is needed, the invisible mark becomes visible under specific conditions, enabling inspection without consuming or wasting any portion of the medium.
Solution Approach 2:
The patent uses a temporary, condition-dependent marking method where the inspection mark exists only when needed (under specific environmental conditions) and disappears or becomes invisible under normal conditions. This allows the medium to be fully utilized as a product without permanent markers, effectively eliminating medium consumption for inspection purposes.
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
Enables the identification of defective nozzle usage without compromising the usability of the printed medium, allowing for efficient quality evaluation and resource utilization.
Implementation Method 1
the special liquid is a liquid rendered invisible depending on an elapsed time after printing on the medium or an environment in which the printed result on the medium is visually recognized
Data Source
AI summary
A printing apparatus includes a first printing unit including a plurality of nozzles configured to eject ink onto a medium, a second printing unit configured to perform printing on the medium using a special liquid, a defective nozzle detector configured to detect a defective nozzle among the plurality of nozzles, and a control unit configured to control the first printing unit and the second printing unit. The special liquid is a liquid rendered invisible depending on an elapsed time after printing on the medium or an environment in which a printed result on the medium is visually recognized.