Developing Unit Cartridge Separation Mechanism
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Solution Overview
Problem
In image forming apparatuses using electrophotographic processes, the existing mechanisms for separating photosensitive drums and developing rollers require significant force, leading to increased cost and size due to the need for high-output motors, and result in image density unevenness and premature deterioration of components.
Innovation Solution
A cartridge configuration with a developing unit supported by rotary shafts at both ends, featuring a biasing member to bring the developing roller into contact with the photosensitive drum, and a slidable support mechanism that allows the developing unit to rotate and separate from the drum using a reduced force by optimizing the action point of the biasing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a pressurizing spring mechanism is used to bring the developing roller into contact with the photosensitive drum, then the developing roller can be pressed against the photosensitive drum with sufficient force for effective development, but a great force is required to separate the developing roller from the photosensitive drum, leading to increased cost and size due to high-output motors
Solution Approach 1:
The developing unit is designed to dynamically change its position between contact and separation states. During development, the developing roller contacts the photosensitive drum under spring pressure. During non-development periods, the developing unit rotates about the support shaft to separate the roller from the drum, eliminating the need for high-power separation motors while maintaining effective contact force during operation.
Solution Approach 2:
The support mechanism is divided into two functional parts: a pressurizing spring that provides contact force during development, and a support shaft that enables rotation for separation. This segmentation allows the system to achieve both sufficient contact pressure and easy separation without requiring a high-power motor for the separation function.
2Ease of operation
If the developing roller is held in continuous contact with the photosensitive drum, then the developing unit remains ready for immediate development, but developer is unnecessarily transferred onto the photosensitive drum and components deteriorate prematurely
Solution Approach 1:
The developing unit operates in periodic cycles: during development operations, the roller contacts the photosensitive drum; during non-development periods, the unit automatically separates by rotating about the support shaft. This periodic contact-separation action maintains readiness for development while preventing continuous contact that would cause unnecessary developer transfer and component deterioration.
3Duration of action of stationary object
If the elastic layers of the developing rollers are kept in contact with the photosensitive drums for long periods, then the developing rollers remain positioned for immediate use, but the elastic layers become deformed causing image density unevenness
Solution Approach 1:
The system implements periodic contact and separation: during development, the elastic layer contacts the photosensitive drum; during non-development periods, the developing unit separates by rotating about the support shaft. This periodic action prevents prolonged contact that would cause elastic layer deformation and resulting image density unevenness, while maintaining operational readiness when needed.
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
This configuration reduces the necessary separation force, enhances image formation consistency, and prolongs the lifespan of components by minimizing unnecessary contact and wear between the photosensitive drum and developing roller, while also downsizing and reducing the power requirements of the apparatus.
Implementation Method 1
a biasing member provided on a same side as one of the two support mechanisms with respect to the developing unit, the biasing member being configured to apply a biasing force to the developing unit so as to bring the developing roller into contact with the photosensitive drum
Implementation Method 2
two support mechanisms each configured to rotatably support the developing unit by a rotary shaft at an each end of both ends of the cartridge
Data Source
AI summary
A cartridge removably mountable to an image forming apparatus, including: a developing unit having a developing roller; two support mechanisms each configured to rotatably support the developing unit by a rotary shaft at an each end of the cartridge; and a biasing member provided on one support mechanism and configured to apply a biasing force to bring the roller into contact with a photosensitive drum, wherein a force against the biasing force is applied to the developing unit to rotate the developing unit to separate the roller from the drum, and in a projection plane orthogonal to the rotary shaft, an action point on which the biasing force acts is arranged between a first line connecting rotation centers of the roller and the drum and a second line passing through the support shaft in parallel with a slide direction of the support shaft slidably supported by the one support mechanism.