Developing Device Charging Roller Separation Mechanism
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Solution Overview
Problem
The existing developing devices for electrophotographic image forming apparatuses face issues with the charging roller deforming and damaging the photosensitive member due to contact, leading to printing defects and reduced quality, and are prone to positional changes during handling, which can cause shock and further damage.
Innovation Solution
A developing device with a separating member that includes a friction member to selectively contact and separate the charging roller from the photosensitive drum, utilizing a rotary shaft and elastic member to manage the contact and separation, and a lever for manual positioning, reducing the risk of deformation and shock-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charging roller continuously contacts the photosensitive member, then the charging function is maintained, but the charging roller deforms and damages the photosensitive member
Solution Approach 1:
The patent applies the dynamics principle by making the contact state between the charging roller and photosensitive member changeable. A movable contact member is introduced that can shift the charging roller between contact and separation positions, allowing the system to transition from continuous contact to intermittent contact based on operational needs, thus preventing deformation while maintaining charging function.
Solution Approach 2:
The patent extracts the harmful continuous contact state by introducing a separate contact member that can be positioned to separate the charging roller from the photosensitive member. This extraction allows the charging roller to be removed from the harmful contact state while maintaining the necessary charging function through controlled contact periods.
2Object-affected harmful factors
If the charging roller is separated from the photosensitive member, then deformation is prevented, but the charging function is lost
Solution Approach 1:
The system dynamically adjusts the contact state by moving the contact member between separated and contacting positions. This allows the charging roller to be separated from the photosensitive member to prevent deformation, then brought into contact when charging is needed, thus resolving the contradiction between prevention and maintenance of charging function.
Solution Approach 2:
The contact member is pre-positioned in a separated state to prevent deformation before charging operations. When charging is required, the contact member is moved to bring the charging roller into contact with the photosensitive member, ensuring the charging function is maintained only when necessary.
3Ease of operation
If the developing device is handled casually, then ease of operation is improved, but shock occurs and causes damage
Solution Approach 1:
The patent applies beforehand cushioning by introducing a movable contact member with elastic properties that can absorb shock during handling. This cushioning mechanism protects the charging roller and photosensitive member from shock-induced damage while allowing casual handling, thus resolving the contradiction between ease of operation and damage prevention.
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
The solution effectively reduces the risk of deformation and shock-induced damage to the photosensitive layer, ensuring consistent image quality by allowing controlled contact and separation of the charging roller, thereby minimizing printing defects and improving handling safety.
Implementation Method 1
a contact portion extending from the body and contacting the surface of the photosensitive drum when the separating member is located at the first position so as to separate the charging roller from the photosensitive drum, wherein the contact portion includes a friction member comprising rubber
Implementation Method 2
an elastic member providing the shaft supporting member with a pressing force in a direction in which the charging roller contacts the photosensitive drum
Data Source
AI summary
A developing device that attaches/detaches to/from a main body of an image forming apparatus includes a photosensitive drum, a charging roller to rotate while contacting the photosensitive drum to charge a surface of the photosensitive drum to a uniform potential, and a separating member to rotate between a first position where the charging roller is separated from the photosensitive drum and a second position where the charging roller contacts the photosensitive drum. The separating member includes a body into which a rotary shaft of the charging roller is inserted to be rotatable, and a contact portion extending from the body and contacting the surface of the photosensitive drum when the separating member is located at the first position so as to separate the charging roller from the photosensitive drum, wherein the contact portion includes a friction member including rubber.