Capacitance Sensor Toner Detection in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face issues with toner detection, including toner leakage due to hole formation in storage portion walls, high costs, and high power consumption of piezoelectric sensors, as well as uncertainty in initial toner presence when using capacitance sensors.
Innovation Solution
An image forming apparatus with a storage portion, first and second electrodes, a detected portion capable of moving between the electrodes, and a controller that measures capacitance changes to determine toner presence and supply it accordingly, using a capacitance sensor system that does not require a hole in the storage portion wall and reduces power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric sensor is used for toner detection, then toner presence can be detected, but the sensor cost is high and power consumption is large
Solution Approach 1:
The patent replaces the piezoelectric sensor with a capacitance sensor system that uses electrical field measurement instead of mechanical piezoelectric effect. The capacitance sensor measures changes in capacitance value caused by toner presence, achieving detection functionality with lower power consumption and cost while maintaining measurement accuracy.
Solution Approach 2:
The patent changes the detection parameter from piezoelectric signal to capacitance value. By measuring capacitance changes between electrodes as toner moves through the storage portion, the system achieves effective toner detection using a more energy-efficient and cost-effective sensing mechanism.
2Measurement precision
If a piezoelectric sensor is used for toner detection, then toner presence can be detected, but the sensor cost is high
Solution Approach 1:
The patent employs a capacitance sensor system that uses inexpensive electrodes and simple circuitry instead of costly piezoelectric sensors. The capacitance detection method can be implemented with basic electronic components, significantly reducing manufacturing cost while maintaining adequate detection precision for toner presence monitoring.
Solution Approach 2:
The patent replaces the expensive piezoelectric sensor with a capacitance-based detection system using simple electrodes and voltage measurement circuitry. This substitution dramatically reduces component cost while achieving the same functional goal of toner presence detection through electrical field interaction with the toner particles.
3Use of energy by moving object
If a capacitance sensor is used for toner detection, then power consumption is reduced, but the initial toner presence state is unknown
Solution Approach 1:
The patent implements a preliminary detection phase where the capacitance sensor measures the capacitance value before toner is supplied to the storage portion. This initial measurement establishes a baseline capacitance value representing the empty state, enabling the system to subsequently detect when toner is present by comparing against this predetermined reference value.
Solution Approach 2:
The patent uses feedback by continuously monitoring capacitance changes and comparing them against the predetermined capacitance value obtained in the initial state. When the measured capacitance deviates from the baseline by a predetermined threshold, the system determines toner presence, creating a closed-loop detection mechanism that resolves the initial state uncertainty.
4Ease of manufacture
If a hole is formed on the storage portion wall for sensor installation, then sensor can be installed, but toner leakage occurs
Solution Approach 1:
The patent replaces the physical hole-based sensor installation with a non-contact capacitance sensing method. Electrodes are positioned on the outer surface of the storage portion wall, and toner detection is achieved through electrical field penetration without physical penetration, completely eliminating the toner leakage risk while maintaining sensor installation simplicity.
Solution Approach 2:
The patent uses the storage portion wall itself as an intermediary medium. The wall acts as a dielectric barrier that allows electrical field interaction between external electrodes and internal toner without requiring physical penetration. This intermediary approach enables sensor functionality while preserving the integrity and密封性 of the storage portion.
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
Effectively detects toner presence without wall holes and expensive sensors, reducing costs and power usage, while accurately determining toner levels for efficient supply.
Implementation Method 1
a capacitance sensor that measures a change of capacitance between the first electrode and the second electrode
Data Source
AI summary
According to one embodiment, an image forming apparatus includes a storage portion, a first electrode, a second electrode, a measuring unit, a detected portion, an image forming unit, and a controller. The storage portion stores a recording material. The measuring unit measures a change of capacitance between the first electrode and the second electrode. The detected portion is located inside the storage portion and is capable of moving so that at least one of a distance to the first electrode and a distance to the second electrode changes. The image forming unit forms an image with the recording material. The controller controls supplying of the recording material to the storage portion in response to the change of the capacitance measured by the measuring unit.