Sensor Lever Chattering Elimination via Preliminary Anti-Action
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Solution Overview
Problem
Existing sheet detecting apparatuses in image forming devices suffer from chattering phenomena due to the sensor lever rebounding upon returning to its home position, leading to erroneous detection and limitations in increasing sheet conveying and image forming speeds.
Innovation Solution
A detection apparatus featuring a rotating member with an elastic member and a regulation unit that prevents the sensor lever from rebounding by using a repulsion force, ensuring accurate detection without chattering by maintaining the sensor in a stable posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotatable sensor lever with elastic member is used to detect sheet passage timing, then the sheet detection function is achieved, but the sensor lever rebounds upon returning to home position causing chattering phenomenon and erroneous detection
Solution Approach 1:
The regulation unit applies a repulsion force to the rotating member in advance before the elastic member can cause the member to rebound upon returning to the home position. This preliminary counter-action prevents the chattering phenomenon by restraining the rotating member from moving into the detection area during the return stroke, thereby eliminating erroneous detection signals while maintaining reliable sheet passage detection.
2Productivity
If the sheet conveying speed is increased to improve productivity, then the image forming speed increases, but the chattering phenomenon causes erroneous detection limiting the speed increase
Solution Approach 1:
By applying the repulsion force through the regulation unit before the rotating member can rebound, the system eliminates the chattering phenomenon that previously limited sheet conveying speed. This allows the sheet conveying speed to be increased for improved productivity while maintaining reliable sheet detection, as the regulation unit prevents erroneous detection signals regardless of the conveying speed.
3Reliability
If the inter-sheet distance is increased to allow for chattering to subside, then the chattering effect is reduced, but the sheet conveying speed and image forming speed are limited
Solution Approach 1:
The regulation unit applies repulsion force to the rotating member in advance, preventing the chattering phenomenon at its source. This eliminates the need to increase inter-sheet distance to allow chattering to subside, thereby reducing the time loss between sheets while maintaining detection stability and reliability.
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
Prevents erroneous detection and allows for higher sheet conveying and image forming speeds by eliminating the chattering phenomenon, ensuring reliable sheet detection and improved operational efficiency.
Implementation Method 1
an elastic member which elastically applies a force to the rotating member in a direction opposite to the rotation direction
Implementation Method 2
an optical sensor such as a photo interrupter. The sensor lever is applied by a force in a direction abutting onto the sheet, and is rotatably pushed down when the sheet passes through. Therefore, the photo interrupter is operated such that a detection area of the photo interrupter is closed or opened
Data Source
AI summary
A detection apparatus includes a rotating member which rotates in a rotation direction from a standby posture by being pushed by a conveyed sheet, a sensor of which an output is changed as the rotating member rotates from the standby posture, an elastic member which elastically applies a force to the rotating member in a direction opposite to the rotation direction, a first abutting portion which abuts onto the rotating member applied by a force by the elastic member to maintain the rotating member in the standby posture, and a regulation unit which allows the rotating member to rotate in the rotation direction by being pushed by the conveyed sheet and regulates the rotating member not to rotate in the rotation direction by a repulsion force when the rotating member rotated in the opposite direction by an elastic force of the elastic member abuts onto the first abutting portion.