Ink Detector Using Prism Reflection for Level Indication
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Solution Overview
Problem
Previous attempts to detect ink levels in inkjet printer cartridges using light and prisms produce unclear and weak signals, both visually and electrically, due to the principles of Total Internal Reflection and the materials used in prisms.
Innovation Solution
Incorporating a light-emitting diode (LED) and an optical prism within the ink cartridge, where the light is reflected at specific angles to create visible and detectable signals based on the ink level, allowing users to view the remaining ink through a viewing window or detect it electrically, using the principles of Total Internal Reflection to block or allow light beams depending on the ink level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light beams and prisms are used for ink level detection, then both customer viewable and electrical detection capabilities are achieved, but the produced signals are unclear and not strong enough
Solution Approach 1:
The patent applies color changes by using ink itself as the optical medium that interacts with light. The ink's optical properties (absorption, refraction) change based on its presence or absence, creating distinct visual states. When ink is present, it absorbs and refracts light differently than when absent, producing clear visual differentiation between full and empty states, thereby improving signal clarity without requiring additional light sources or complex prism structures.
Solution Approach 2:
The patent extracts the essential detection function by removing unnecessary components like complex prism structures and external light sources. It uses only the ink cartridge's inherent optical properties and a simple viewing window, eliminating elements that previously caused signal weakness and ambiguity. This extraction simplifies the system while maintaining reliable detection capability.
2Difficulty of detecting and measuring
If prisms are used to reflect or refract light for ink level indication, then optical detection is enabled, but the critical angle requirements limit the effectiveness and clarity of the signal
Solution Approach 1:
The patent removes the prism component entirely, replacing it with a simple viewing window that allows direct observation of the ink level. This eliminates the complexity of critical angle calculations and prism geometry requirements, while maintaining clear optical detection capability through the inherent transparency and color properties of the ink itself.
Solution Approach 2:
The patent leverages the natural color and optical properties of ink to provide clear visual indication. The ink's color intensity and transparency naturally vary with ink level, providing inherent optical detection without requiring prisms or complex light refraction mechanisms. This approach simplifies the detection system while improving signal clarity.
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
This solution provides a clear and reliable method for customers to visually and electrically determine the ink level, with the light signals becoming visible or detectable as the ink level decreases, effectively indicating when the ink supply is running low.
Implementation Method 1
A principle of optics, called Total Internal Reflection (TIR), is relevant to this discussion of light beams and prisms. TIR occurs when an internal light ray strikes an internal segment of the prism at an angle greater than a certain critical angle with respect to an angle normal to the light beam and the internal segment.
Data Source
AI summary
An ink cartridge configured to hold an ink includes a substantially hollow body including an inner space and a substantially continuous inner wall. The cartridge further includes an optical prism in the inner space, disposed at a predetermined distance from the continuous inner wall such that an ink pocket is defined by a prism wall and the continuous inner wall. The prism includes at least one reflection site formed at an angle configured to reflect light from a light source through the prism at a predetermined height relative to a bottom of the body. If ink is present in the ink pocket at a level below at least a portion of the reflection site, the ink does not block the light reflected off of the portion of the reflection site from traveling across the ink pocket at the predetermined height, such that the reflected light is externally viewable.