Print Material Level Sensor Parasitic Voltage Compensation
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Solution Overview
Problem
Existing print material level sensors face challenges in accurately determining the remaining amount of print material due to parasitic voltage drops in narrow wiring, leading to inconsistent power delivery and reduced sensitivity, especially for heaters further away from the power source.
Innovation Solution
The implementation of a series of print material level sensing devices with control circuitry that heats each depth zone until a target signal value is reached, ensuring consistent measurement across all zones, regardless of distance from the power source, using a comparator to manage electrical power and a digital to analog converter to maintain a consistent starting temperature for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If narrow wiring is used to connect sensing devices, then device complexity is reduced, but parasitic voltage drops increase causing inconsistent power delivery
Solution Approach 1:
The control circuitry continuously monitors the signal output from each sensing device and adjusts the power delivery in real-time. When a sensing device outputs a target signal value indicating sufficient heating, the control circuitry maintains or adjusts power levels to compensate for parasitic voltage drops, ensuring consistent measurements across all depth zones.
Solution Approach 2:
The system dynamically changes power delivery parameters (voltage, current, or power levels) to each sensing device based on its specific distance from the power source. This allows the system to compensate for parasitic voltage drops by delivering higher power to distant devices and lower power to nearby devices, achieving uniform heating and consistent signal outputs.
2Measurement precision
If heating power is increased to improve signal detection, then measurement precision improves, but temperature control accuracy decreases
Solution Approach 1:
The control circuitry applies periodic or pulsed heating to the sensing devices rather than continuous heating. By controlling the duty cycle and duration of heating pulses, the system achieves sufficient temperature elevation for accurate signal detection while preventing excessive temperature accumulation that would compromise temperature control accuracy.
Solution Approach 2:
The system dynamically adjusts heating power levels based on real-time feedback from sensing devices. The control circuitry modulates power delivery to maintain optimal temperature ranges for measurement precision while avoiding overheating, enabling adaptive temperature control that responds to changing conditions in the print material container.
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 approach ensures accurate and consistent determination of print material levels, maintaining a high signal-to-noise ratio and reducing errors, even as the container approaches emptiness, by compensating for parasitic voltage drops and ensuring uniform power delivery to all sensing devices.
Implementation Method 1
a heater of the print material level sensing device emits heat when supplied with electrical power
Implementation Method 2
a thermal sensor of the print material level sensing device outputs a signal based on heat sensed by the thermal sensor
Data Source
AI summary
A print material level sensor includes a series of print material level sensing devices disposed at intervals to detect the presence of print material at successive depth zones in a container. Each print material level sensing device includes a heater to emit heat at its depth zone and a sensor to sense heat at the depth zone and to output a signal based on the heat sensed. The print material level sensor includes control circuitry to enable supply of electrical power to the heater of any one of the print material level sensing devices in its depth zone and to receive the signal from the respective sensor. The control circuitry includes a comparator to compare a value of the signal to a target value. The control circuitry disables supply of the electrical power to the heater when the value of the signal is at least equal to the target value.