Stop Member Segmentation for Roller Stability in Sheet Cassette
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Solution Overview
Problem
Conventional image forming apparatuses experience unstable sheet conveying performance due to reaction forces from the stop member, which can separate the first roller from the second roller, disrupting the cooperative sheet conveying process.
Innovation Solution
The design includes a stop member that moves from a first position to a second position when the sheet cassette is moved from an external to an internal position, allowing the pendulum gear to transition from a separated to a meshing position without contacting the sheet cassette in a direction that would cause separation of the rollers, thereby stabilizing the conveying performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stop member contacts the sheet cassette in the direction from the internal position to the external position, then the pendulum gear can be retained at the separated position, but the reaction force from the stop member separates the first roller from the second roller, causing unstable sheet conveying performance
Solution Approach 1:
The stop member is divided into a first stop portion and a second stop portion with different functions. The first stop portion contacts the sheet cassette in the first direction (internal to external) to retain the pendulum gear, while the second stop portion contacts in the second direction (perpendicular to first direction) without causing roller separation. This segmentation allows each portion to perform its specific function independently.
Solution Approach 2:
Different portions of the stop member have different contact characteristics with the sheet cassette. The first stop portion is designed to contact in the first direction for gear retention, while the second stop portion contacts in the second direction without applying separating force. This local differentiation of contact quality resolves the contradiction between gear retention and roller stability.
2Adaptability or versatility
If the stop member is positioned to retain the pendulum gear at the separated position, then the gear train can be disengaged, but the reaction force applied to the sheet cassette disrupts the cooperative conveying of sheets by the first and second rollers
Solution Approach 1:
The stop member is segmented into two functional portions: the first stop portion for gear train disengagement control and the second stop portion for stable positioning without disrupting roller contact. This segmentation enables independent optimization of each function.
Solution Approach 2:
The second stop portion acts as an intermediary contact point that provides necessary reaction force for positioning the stop member while directing the force in a direction (second direction) that does not interfere with the roller-cooperating force direction (first direction), thus mediating between gear control and conveying stability requirements.
Data Source
AI summary
An image forming apparatus including a housing, a sheet cassette, a second roller, a gear train, a pendulum gear, and a stop member. The gear train includes a gear rotatable together with the second roller. The pendulum gear is movable between a meshing position where the pendulum gear is in meshing engagement with the gear train and a separated position where the pendulum gear is separated away from the gear train. The stop member allows the pendulum gear to move from the separated position to the meshing position. In the state where the sheet cassette is at an internal position and the stop member is at the second position, the stop member is out of contact with a part of the sheet cassette in a first direction but contacts the part of the sheet cassette in a second direction.