Photoconductor Drum Protection via Movable Shield in Image Forming Apparatus
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Solution Overview
Problem
The circumferential surface of the photoconductor drum in image forming apparatuses is prone to scratches during drum cartridge replacement due to exposure when the drum cartridge is mounted and the drawer is in the drawn position.
Innovation Solution
Incorporating a moving member that can shift between two positions, one where it protects the photoconductor drum's surface and another where it allows contact with the belt, ensuring the drum's surface is shielded during cartridge operations and exposed for belt contact when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drum cartridge is mounted on the drawer and the drawer is located at the drawn position, then the belt can contact the photoconductor drum for image formation, but the circumferential surface of the photoconductor drum is exposed and prone to scratches
Solution Approach 1:
The patent employs a movable protective member that dynamically changes position based on drawer location. When the drawer is in the drawn position, the protective member covers the photoconductor drum surface to prevent scratches. When the drawer moves to the accommodated position, the protective member retracts to allow belt contact for image formation. This dynamic adjustment resolves the contradiction between protection and functional operation.
Solution Approach 2:
The protective member is positioned in advance to cover the photoconductor drum surface before any replacement work begins. This preliminary protective action ensures the drum surface is shielded during cartridge removal and installation operations, preventing scratches before they can occur while maintaining the ability to proceed with replacement work.
2Object-affected harmful factors
If a protective structure is added to shield the photoconductor drum surface, then scratch protection is improved, but the device structure becomes more complex
Solution Approach 1:
The protective member is merged with the existing drawer assembly structure rather than being a separate independent component. It is integrated into the drawer's movable mechanism, allowing it to be driven by the drawer's own motion. This merging approach provides scratch protection while minimizing additional structural complexity by utilizing existing structural elements.
Solution Approach 2:
The protective member serves multiple functions: it protects the photoconductor drum surface from scratches, acts as a guide for belt positioning, and integrates with the drawer's movable mechanism. This multi-functionality reduces the need for separate protective components, thereby limiting the increase in device complexity while achieving comprehensive protection.
Data Source
AI summary
An image forming apparatus includes a body housing, a drawer movable between an accommodated position and a drawn position, a drum cartridge including a photoconductor drum, a developing cartridge including a developing roller, and a belt located above the photoconductor drum, and the drawer is located at the accommodated position. The drum cartridge includes a moving member movable, with respect to the photoconductor drum, between (i) a first position which is a position at which the moving member is not opposed to the developing cartridge mounted on the drum cartridge and is opposed to a circumferential surface of the photoconductor drum and (ii) a second position which is a position at which the moving member is not opposed to the circumferential surface of the photoconductor drum and is opposed to the developing cartridge mounted on the drum cartridge.