Ink Cartridge Optical Prism for Reliable Level Detection
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Solution Overview
Problem
Previous attempts to render the ink level in an inkjet printer cartridge viewable and detectable using light and prisms resulted in unclear signals due to the principle of Total Internal Reflection, leading to weak and unreliable detection methods.
Innovation Solution
An ink cartridge design incorporating a light-emitting diode (LED) and optical prisms with predetermined reflection angles, allowing light signals to be accurately reflected and directed out of the cartridge based on ink levels, enabling both visual and electrical detection of ink levels through a viewing window or detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light beams and prisms are used for ink level detection, then both customer viewability and electrical detectability are achieved, but the signals produced are unclear and unreliable
Solution Approach 1:
The patent uses ink's inherent light-absorbing property (optical density) to modulate light signals. When ink is present, it absorbs light and prevents TIR; when ink is absent, light undergoes TIR and reflects back. This creates distinct visual and electrical signals that are clear and unambiguous, directly addressing the signal clarity problem while maintaining detection reliability
Solution Approach 2:
The patent converts the harmful effect of TIR (which causes signal loss and unreliability) into a beneficial detection mechanism. By designing the system to detect the ABSENCE of TIR (when ink is present) rather than its presence, the patent transforms the optical phenomenon from a source of error into a reliable indicator of ink levels
2Illumination intensity
If Total Internal Reflection is used for light signal detection, then light can be reflected within the prism, but the on/off signal produced is generally not strong
Solution Approach 1:
The patent leverages the stark contrast between light absorption (ink present) and light reflection (ink absent) to create strong, distinct signals. The ink's optical properties naturally provide high contrast, resulting in strong on/off signals that are easily detectable both visually and electrically
Solution Approach 2:
The patent introduces the ink itself as an intermediary that mediates the light signal. The ink's presence or absence directly controls whether light undergoes TIR or is absorbed, creating a natural binary signal mechanism that produces strong, reliable detection signals without requiring additional amplification
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 view and detect ink levels, with the light signals being effectively blocked or allowed to pass based on the ink level, providing a countdown to when the ink supply is depleted, ensuring timely replacement.
Implementation Method 1
An ink cartridge design incorporating a light-emitting diode (LED) and optical prisms with predetermined reflection angles, allowing light signals to be accurately reflected and directed out of the cartridge
Implementation Method 2
the light signals being effectively blocked or allowed to pass based on the ink level
Data Source
Figure 1~3
Figure 4~6
Figure 7A~8
AI summary
An ink cartridge (1) configured to hold an ink includes a substantially hollow body (23) including an inner space (21) and a substantially continuous inner wall (5). An optical prism (2, 2'', 2''') in the inner space (21) is disposed at a predetermined distance from the continuous inner wall (5) such that an ink pocket (6) is defined by a prism wall (17) and the continuous inner wall (5). The prism (2, 2'', 2''') includes at least one reflection site (4) formed at an angle configured to reflect light from a light source through the prism (2, 2'', 2''') at a predetermined height relative to a bottom (10) of the body (23). If ink is present in the ink pocket (6) at a level below at least a portion of the reflection site (4), the ink does not block the light reflected off of the portion of the reflection site (4) from traveling across the ink pocket (6) at the predetermined height, such that the reflected light is externally detectable by electronic means (16).