Developing Cartridge Asymmetric Cam Mechanism
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Solution Overview
Problem
Conventional image forming apparatuses require driving force to be applied to both sides to move the developing roller away from the photosensitive drum, which is inefficient and cumbersome.
Innovation Solution
A developing cartridge design featuring a rotatable casing, a first shaft, a pivotable first arm, and a cam mechanism that allows the developing roller to separate from the photosensitive drum when a driving force is applied to only one side, utilizing a pressure contact surface and elastic members for pivotal movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driving force is applied to both sides to move the developing roller away from the photosensitive drum, then the developing roller can be reliably separated, but the mechanism complexity and driving force requirements increase
Solution Approach 1:
The patent applies asymmetry by providing the cam mechanism only on one side of the developing cartridge. The cam on this single side converts linear pressing force into rotational movement of the shaft, which then pivots the arm to separate the developing roller from the photosensitive drum. This asymmetric configuration eliminates the need for symmetric dual-sided driving components while achieving reliable separation through the mechanical advantage of the cam mechanism.
2Reliability
If driving force is applied to both sides to move the developing roller away from the photosensitive drum, then the developing roller can be reliably separated, but the force and energy requirements increase
Solution Approach 1:
The patent employs the curvature principle through the cam mechanism. The cam's curved surface transforms linear pressing force into rotational motion of the shaft. This curvature-based mechanism provides mechanical advantage, allowing a smaller pressing force to generate sufficient torque for separation. The rotational movement created by the cam reduces the overall force requirement compared to direct linear actuation.
3Ease of operation
If components for moving the developing cartridge are provided at each side, then the developing roller can be separated from the photosensitive drum, but the device complexity and space requirements increase
Solution Approach 1:
The patent merges multiple functions into a single-sided cam mechanism. The cam simultaneously performs the functions of force conversion, shaft rotation actuation, and arm pivoting initiation. This consolidation of functions on one side eliminates the need for separate components at both sides, reducing the overall space occupation while maintaining full separation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the developing roller to move away from the photosensitive drum using a driving force applied to only one side, improving efficiency and simplifying the mechanism for contact and separation states.
Implementation Method 1
The cam has: one end; another end; and a pressure contact surface. The one end is connected to the first shaft. The another end is positioned farther from the rotational axis than the one end is farther from the rotational axis. The pressure contact surface is inclined so as to approach the outer surface of the casing as extending from the one end toward the another end.
Implementation Method 2
the first elastic member, the second elastic member
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A developing cartridge (1) includes: a developing roller (30); a casing (10) having an outer surface (11); a first shaft (61) rotatable about a rotational axis (A); a first arm (63) extending from the first shaft (61); and a cam (69) extending from the first shaft (61) differently from the first arm (63). The first arm (63) and the cam (69) are pivotally movable along with rotation of the first shaft (61). The cam (69) has a pressure contact surface (69c) inclined so as to approach the outer surface (11) as extending from one end (69a) toward another end (69b) of the cam (69). When a pressing force is applied to the pressure contact surface (69c), the first arm (63) pivotally moves from a first position to a second position along with pivotal movement of the cam (69) and along with the rotation of the first shaft (61).