Detection Lever Segmentation for Sensor Reliability
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Solution Overview
Problem
Existing image forming apparatuses face issues with optical sensors malfunctioning due to moisture vapor and radiant heat generated during heat fixation, leading to erroneous operations and increased risk of detection lever damage from extended arm lengths when trying to position sensors away from the heat source.
Innovation Solution
The apparatus incorporates a first detection lever and a second detection lever, supported by respective members, with a movable cover portion that activates a detection sensor when the levers move, allowing the sensor to be positioned away from the heat source while minimizing arm length and reducing the risk of damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical sensor is arranged in the door to position it away from the heat source, then the sensor is protected from moisture vapor and radiant heat, but the arm of the detection lever becomes long and sticks out when the door is opened, increasing the risk of breakage
Solution Approach 1:
The detection lever is divided into two separate levers: a first detection lever mounted on the main body and a second detection lever mounted on the door. This segmentation allows each lever to have a shorter arm length, reducing the risk of breakage when the door is opened, while still achieving the goal of positioning the optical sensor away from the heat source.
Solution Approach 2:
The first detection lever acts as an intermediary that transmits the sheet pushing force to the second detection lever. This intermediary mechanism allows the optical sensor to be positioned on the door away from the heat source while maintaining effective sheet detection capability through the coordinated action of both levers.
2Object-affected harmful factors
If the arm of the detection lever is made long to position the optical sensor away from the heat source, then the sensor is protected from thermal effects, but the likelihood of breaking the detection lever increases
Solution Approach 1:
By segmenting the detection lever into two separate levers mounted on different structures (main body and door), the patent reduces the arm length of each individual lever. This segmentation maintains the protective distance from the heat source while preserving the structural strength and reducing breakage risk of each lever component.
3Reliability
If the optical sensor is positioned far from the fixing unit, then the sensor is less susceptible to moisture vapor and radiant heat, but the device complexity increases due to the need for a long arm mechanism
Solution Approach 1:
The patent segments the detection function across two levers mounted on different structures, which simplifies each individual lever's design and reduces the complexity of the overall mechanism compared to using a single long-arm lever. This segmentation approach maintains sensor reliability while avoiding the complexities of a single extended mechanism.
Solution Approach 2:
The patent merges the detection functions of the first and second levers into a coordinated system where both levers work together to detect sheet presence. This merging of functions across two simpler components achieves the same detection capability as a single complex long-arm mechanism while reducing overall system complexity.
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 configuration effectively reduces the impact of thermal deformation and bending moments on detection accuracy, lowers the risk of arm breakage, and prevents sensor failures due to moisture vapor and radiant heat, while maintaining detection precision and reducing maintenance costs.
Implementation Method 1
an optical sensor as the sensor described above, and a detection lever having a sheet detecting portion mounted on a pivotal shaft of the detection lever and a sensor activating portion mounted on the pivotal shaft of the detection lever. The detection lever is configured to be rotated (pivoted) about the pivotal shaft by a contact of the sheet detecting portion with a sheet and block and allow entry of light to a light-receiving portion of the optical sensor by the sensor activating portion in accordance with a rotating action of the detection lever.
Data Source
AI summary
An image forming apparatus includes a main body movably supporting an openable-and-closable portion, and the openable-and-closable portion is provided with a detection sensor. A first detection lever configured to be movable by being pushed by a sheet is provided on the main body, and a second detection lever configured to be capable of moving in conjunction with the movement of the first detection lever is provided on the openable-and-closable portion. The detection sensor is activated by the movement of the second detection lever based on the movement of the first detection lever.