Drum Unit Lock Lever Redesign for Compact Developer Cartridge Arrangement
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Solution Overview
Problem
Existing drum units in electrophotographic image forming apparatuses cannot arrange developer cartridges closely together, leading to a larger size in the direction of photosensitive drums, which hinders downsizing efforts.
Innovation Solution
The drum unit design includes a frame with pivotable lock levers that allow adjacent developer cartridges to be positioned closer, eliminating the need for clearance between them, thus enabling a more compact arrangement of photosensitive drums.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clearance is provided for lock lever pivoting between developer cartridges, then the lock lever can move between lock and release positions, but adjacent developer cartridges cannot be arranged close to each other
Solution Approach 1:
The lock lever is repositioned from a location between adjacent developer cartridges to a location at the end of the drum unit. This spatial relocation in another dimension eliminates the need for clearance between developer cartridges, allowing them to be arranged closely together while the lock lever still has sufficient space to pivot at the end position.
Solution Approach 2:
The lock mechanism is segmented into multiple independent lock levers, each associated with specific developer cartridges. By distributing lock levers to different locations (some at ends, some between cartridges), the system allows compact arrangement of cartridges while maintaining operational independence of each lock mechanism.
2Reliability
If lock levers are positioned between adjacent developer cartridges, then locking function is achieved, but the drum unit size increases in the direction of photosensitive drum arrangement
Solution Approach 1:
Lock levers are positioned at the end of the drum unit in the axial direction rather than between developer cartridges in the radial direction. This dimensional change allows the locking function to be maintained while eliminating the need for additional space between cartridges, thereby reducing the overall drum unit volume.
3Volume of stationary object
If developer cartridges are arranged closely together, then the drum unit is downsized, but clearance for lock lever operation is reduced
Solution Approach 1:
The lock lever operation space is relocated to the end of the drum unit in the axial direction, separate from the radial space between developer cartridges. This allows developer cartridges to be arranged closely together for downsizing while the lock lever maintains full operational clearance at the end position.
Data Source
AI summary
A photosensitive drum is rotatable about a drum axis extending in a first direction. A frame includes a first side plate located at first end in the first direction and a second side plate spaced from the first side plate in the first direction. The frame rotatably supports the photosensitive drum between the first side plate and the second side plate in the first direction. The frame holds a developer cartridge. A lock lever is pivotable about a pivot axis extending in a second direction intersecting with the first direction. The lock lever is movable between a lock position at which the developer cartridge is locked on the frame and a release position at which the developer cartridge is unlocked from the frame.