Photosensitive Drum Unit Mounting Interval Regulation
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Solution Overview
Problem
The existing image forming apparatus designs face challenges in mounting image bearing members without interfering with developing units, leading to increased size and reduced supporting rigidity of photosensitive drums due to the need for larger spacing and potential damage during cartridge exchange.
Innovation Solution
The image bearing member unit incorporates a bearing portion with an arcuate portion and a holding portion that allows for differential phase alignment between the arcuate portion and the passing portion, enabling the bearing portion to be inserted without extending the casing, thus preventing interference with the developing sleeve and maintaining supporting rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the passing portion is provided in the casing of the photosensitive drum unit to permit passage of the arcuate portion, then the bearing portion can be mounted, but the casing is extended outwardly causing interference with the developing sleeve and requiring increased spacing that leads to upsizing of the image forming apparatus
Solution Approach 1:
The passing portion is positioned at a different phase (angular position) than the arcuate portion, allowing the bearing portion to be mounted without extending the casing in the radial direction toward the developing sleeve. This phase difference creates spatial separation in the angular dimension, enabling the bearing to pass through without requiring increased axial spacing between the photosensitive drum and developing sleeve.
2Ease of manufacture
If the bearing portion is mounted at a U-shaped mounting portion with a cut-away edge, then the arcuate portion can pass through, but the supporting rigidity of the photosensitive drum lowers causing vibration during operation
Solution Approach 1:
Instead of creating a U-shaped cut-away that compromises structural integrity, the passing portion is positioned at a different phase (angular position) than the arcuate portion. This phase difference allows the bearing to be mounted through a minimal opening without requiring large cut-aways, thereby maintaining the casing's supporting rigidity and preventing vibration during drum rotation.
3Ease of manufacture
If the phase of the passing portion is aligned with the phase of the arcuate portion, then the bearing portion can be mounted, but the casing must be extended outwardly causing interference with the developing sleeve
Solution Approach 1:
The passing portion is deliberately positioned at a different phase (angular position) than the arcuate portion. This phase difference creates a spatial arrangement where the bearing can be mounted without the casing extending outwardly to interfere with the developing sleeve, enabling smooth extraction and insertion of the photosensitive drum unit without operational interference.
Data Source
AI summary
An image bearing member unit includes an image bearing member for bearing a toner image; a bearing portion which rotatably supports the image bearing member and is coaxial with a rotational axis of the image bearing member and which includes an arcuate portion for forming a circumferential part of a circle large larger than the image bearing member; a holding portion, capable of permitting insertion of the bearing portion in a rotational axis direction of the image bearing member, for holding the bearing portion, and a passing portion, provided in the holding portion, for permitting passage of the arcuate portion therethrough in the rotational axis direction. The passing portion is provided so that a phase of the arcuate portion when the bearing portion is mounted at a normal position and a phase of the passing portion are different from each other.