Developing Cartridge Detection Target Positioning for Downsizing
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Solution Overview
Problem
Conventional developing cartridges for electro-photographic image forming apparatuses are larger due to the need for external gear mechanisms, which occupy space orthogonal to the central axis, making them bulkier and limiting their downsizing potential while maintaining new/unused detection functionality.
Innovation Solution
The developing cartridge design incorporates a detection target unit with a detection target portion that moves between the agitation gear and the gear cover, allowing for effective space utilization and downsizing by positioning the detection target unit between the second gear and the gear cover, enabling appropriate new/unused detection without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gears are positioned on the outside of the first side wall, then the driving force can be transmitted to the detection objective rotating part, but the developing cartridge becomes larger in the direction orthogonal to the central axis of each gear
Solution Approach 1:
The patent repositions the detection target portion from the conventional external location to the internal space between the second gear and the gear cover. This spatial reconfiguration utilizes the third dimension (depth along the gear axis) to accommodate the detection mechanism, thereby reducing the cartridge's external dimensions while maintaining detection functionality.
Solution Approach 2:
The detection target unit is nested within the existing gear structure by positioning it between the second gear and the gear cover. This nesting approach allows the detection mechanism to share the same spatial envelope as the drive mechanism, eliminating the need for additional external space and reducing overall cartridge volume.
2Reliability
If a gear cover is attached to cover the gears, then the gears are protected, but the developing cartridge becomes even larger due to the space required for the engaging portion
Solution Approach 1:
The patent combines the gear cover's protective function with the detection target unit's housing function. The gear cover is designed to simultaneously protect the gears and provide the structural boundary for the detection target portion, merging two separate components into one integrated element. This eliminates the need for additional space for a separate detection target housing, thereby reducing cartridge size while maintaining gear protection.
Data Source
AI summary
A developing cartridge includes: an agitation member configured to be rotatable around a rotational shaft extending in a first direction and to agitate a developer; an agitation gear being fixed to the agitation member and including a first gear configured to receive driving force to be inputted and a second gear positioned on one side of the first gear in the first direction; a detection target unit including a detection target receiving portion configured to receive the driving force from the second gear and a detection target portion configured to be detected by an external detecting apparatus; and a gear cover configured to cover at least a part of the agitation gear and the detection target unit therewith. The detection target portion is configured to move between the second gear and the gear cover when being projected in a direction orthogonal to the first direction.