Developing Cartridge Coupling Member Noise Reduction
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the engagement and disengagement of coupling members often result in noise due to the use of elastic urging means like coil springs to maintain the pre-engagement angular position, which can cause abrupt movements and noise during disengagement.
Innovation Solution
A developing cartridge design that utilizes an inclination regulating member to position the coupling member in the pre-engagement angular position without relying on elastic urging means, allowing for smooth engagement and disengagement without noise, by using a mechanism where the coupling member is abutted by a function member during rotation to change its position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastic urging means such as coil springs are used to maintain the pre-engagement angular position of the coupling member, then the coupling member can be assuredly placed in the pre-engagement angular position, but noise is generated during engagement and disengagement due to abrupt movements
Solution Approach 1:
The patent removes the elastic urging means (coil spring) from the system entirely. Instead of using a spring to maintain the pre-engagement angular position, the invention uses a cam mechanism with a cam surface and cam follower that geometrically constrains the coupling member to the correct angular position during engagement, eliminating the noise source while maintaining positioning reliability
Solution Approach 2:
The patent introduces a cam mechanism as an intermediary between the driving shaft and the coupling member. The cam surface and cam follower work together to smoothly guide the coupling member into the pre-engagement angular position without abrupt movements, replacing the direct spring-action with a controlled geometric interface that mediates the engagement process
2Reliability
If elastic urging means are used to position the coupling member, then engagement reliability is improved, but the device complexity increases due to additional components
Solution Approach 1:
The patent merges the positioning function previously performed by the elastic spring into the cam mechanism itself. The cam surface geometry inherently provides the pre-engagement angular positioning without requiring a separate spring component, thereby reducing overall device complexity while maintaining engagement reliability
Solution Approach 2:
By removing the elastic urging means entirely and replacing it with a cam-based geometric constraint system, the patent reduces the number of components needed. The cam mechanism integrates multiple functions (positioning, guiding, and engagement control) into a single structural element rather than requiring separate spring and positioning components
Data Source
AI summary
A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular position, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.