Sensor Lever Force Alignment for Sheet Detection Noise Reduction
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Solution Overview
Problem
Conventional sheet detecting devices in image forming apparatuses generate noise due to the mismatched directions of force applied to the rotational shaft of the sensor lever, resulting from the play between the rotational shaft and its bearing, when the sensor lever returns to its stand-by position.
Innovation Solution
The design includes a rotatable member with a rotational shaft, a detecting portion, a supporting member, an urging member, and a restricting member, where the urging member and restricting member ensure that the forces acting on the rotational shaft in the stand-by and return directions are aligned, reducing the angle between these forces to 20 degrees or less, thereby minimizing the positional fluctuation of the rotational shaft and subsequent noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor lever rotates to return to the stand-by position, then the sheet detection function is completed, but the play between the rotational shaft and bearing causes vibration and loud noise
Solution Approach 1:
The invention introduces a counterbalancing weight on the sensor lever that offsets the vibrational forces generated during rotation. This counterweight creates opposing forces that cancel out the harmful vibrations caused by the play between the rotational shaft and bearing, thereby reducing operating noise while maintaining the sheet detection function.
Solution Approach 2:
The invention employs damping elements or cushioning structures positioned to absorb and mitigate vibrations before they propagate as noise. These cushioning measures are built into the sensor lever assembly to preemptively reduce the amplitude of vibrations generated during the rotation and return motion, addressing the noise problem at its source.
2Ease of operation
If the rotational shaft is supported by a bearing to enable rotation, then the sensor lever can detect sheets, but the play between the shaft and bearing causes positional fluctuation and noise
Solution Approach 1:
The invention introduces an intermediary element, such as a precision bushing or intermediate bearing, between the rotational shaft and the main bearing support. This intermediary component reduces the clearance or play between the shaft and bearing, thereby improving positional stability and reducing vibrations while still allowing smooth rotation for sheet detection.
Solution Approach 2:
The invention modifies the physical parameters of the rotational system, such as reducing the clearance between the rotational shaft and bearing, or changing the material properties of the bearing to reduce play. By adjusting these parameters, the system achieves both smooth rotation capability and improved positional stability, eliminating the noise caused by excessive clearance.
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 significantly reduces the operation noise of the sensor lever by minimizing the amplitude of vibration caused by the play between the bearing and rotational shaft, enhancing the operational quietness of the sheet detecting device.
Implementation Method 1
an optical sensor such as a photo interrupter that detects the rotation of the rotatable member
Implementation Method 2
a torsion spring to urge the sensor lever in a predetermined rotational direction
Data Source
AI summary
A sheet detecting device includes a lever provided with a rotational shaft, a spring and a stopper. The lever is positioned in a stand-by position in a state of being in non-contacting with a sheet, and rotates about the rotational shaft from the stand-by position in a first rotational direction by being contacted with the sheet fed. The spring urges so as to rotate the lever in a second rotational direction opposite to the first rotational direction. The stopper restricts rotation of the lever beyond the stand-by position in the second rotational direction by being contacted with the lever after contacting of the sheet with the lever. A direction of a first force acting on the rotational shaft by the spring in a case in which the lever is positioned in the stand-by position is the substantially same direction as a direction of a second force which the lever receives from the stopper when the lever is in contact with the stopper by rotating in the second direction.