Toner Amount Detection Sensor with Slit Shielding
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Solution Overview
Problem
Existing toner amount detection sensors in image forming apparatuses face challenges in accurately measuring toner amounts on transfer bodies, particularly when the toner coverage is incomplete or the toner amount is small, leading to inaccuracies in color correction and image quality.
Innovation Solution
A toner amount detection sensor with a light emitting element and a light receiving element, positioned at specific angles to detect specular and diffuse-reflected light, calculates toner amount by analyzing the light quantity received, utilizing a substrate with slits and a case housing with light shielding walls to prevent direct light interference, allowing for precise toner amount measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a typical optical sensor is used to detect toner amount, then the sensor structure is simple, but the measurement precision deteriorates when toner coverage is incomplete or toner amount is small
Solution Approach 1:
The sensor divides the detected light into two distinct paths: specular reflection light (direct reflection from the transfer belt surface) and diffuse reflection light (light scattered by toner particles). By using separate light receiving elements for each path, the sensor can independently measure both components, enabling accurate toner amount detection even when coverage is incomplete or toner amount is small.
Solution Approach 2:
The sensor transitions from measuring only total reflected light intensity to measuring the angular distribution of reflected light by detecting both specular and diffuse components at different angles. This dimensional change in measurement approach allows the sensor to distinguish between light reflected from the bare transfer belt surface and light scattered by toner, significantly improving measurement precision.
2Device complexity
If the light emitting element and light receiving element are positioned close together, then the device complexity is reduced, but light interference between the elements increases
Solution Approach 1:
The sensor extracts and isolates the harmful direct light path from the useful reflected light paths by using a light shielding member. This shielding structure blocks direct light from the light emitting element from reaching the light receiving element, eliminating the interference while allowing the sensor elements to remain in a compact configuration.
3Adaptability or versatility
If specular reflection light detection is used for black toner control, then the detection is simple, but the adaptability deteriorates for detecting other toner colors and amounts
Solution Approach 1:
The sensor achieves multi-functionality by simultaneously detecting both specular and diffuse reflection light components. This dual-detection capability allows the same sensor to perform black toner adhesion amount control (using specular reflection), adhesion amount control for other toner colors (using diffuse reflection), and color alignment detection, making it a universal detection system for all toner-related measurements.
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 enables accurate detection of toner amounts, even when coverage is incomplete or small, improving the accuracy of toner adjustments and ultimately enhancing image quality by maintaining optimal color reproduction and correction.
Implementation Method 1
the light receiving element receives a reflected light reflected from the surface side of a transfer body
Implementation Method 2
detecting the toner amount by analyzing the light quantity received
Data Source
AI summary
A toner amount detection sensor has a substrate, and a case housing. In the substrate, the light emitting element, the first light receiving element, and the second light receiving element are attached with an interval to the same first surface. In the substrate, first and second slits and are provided between a region where the light emitting element is attached and regions where the first light receiving element and the second light receiving element are attached. In the case housing, first and second light shielding walls and are disposed in such a manner as to extend to reach the inside of the first and second slits and when attached to the substrate and first and second light shielding walls and are provided between the light emitting element and the first light receiving element and between the light emitting element and the second light receiving element.