Cam Member Charging Roller Separation Mechanism
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Solution Overview
Problem
Conventional image-forming apparatuses with photoreceptor drums and charging rollers have complex structures due to the use of gears for separating and contacting these components, leading to increased size and cost.
Innovation Solution
A process unit with a cam member rotatably positioned on the charging roller's shaft, allowing the charging roller to be switched between separate and contact states through frictional forces with the photoreceptor drum, reducing the need for gears and maintaining a compact longitudinal size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gears are used to separate and contact the charging roller and photoreceptor drum, then the separation and contact function is achieved, but the structure becomes complicated and the longitudinal size increases
Solution Approach 1:
The patent extracts the essential function of gear teeth (engagement and disengagement) and applies it to the cam member's contact portion. The cam member's contact portion engages with the photoreceptor drum's outer surface through frictional force, achieving separation and contact without requiring traditional gear mechanisms. This simplifies the overall structure while maintaining the separation and contact functionality.
Solution Approach 2:
The patent replaces the traditional mechanical gear system with a friction-based cam member mechanism. Instead of using interlocking gear teeth, the cam member uses its contact portion to frictionally engage with the photoreceptor drum's outer surface. This substitution eliminates the need for complex gear structures while achieving the same separation and contact effect.
2Ease of operation
If gears are provided on both sides of the photoreceptor drum, then the separation and contact function is achieved, but spaces must be secured and the longitudinal size increases
Solution Approach 1:
The patent repositions the cam member within the longitudinal range of the photoreceptor drum's drum main body, utilizing the radial and axial dimensions more efficiently. Instead of extending beyond the drum's longitudinal boundaries with gear mechanisms, the cam member is integrated into the existing longitudinal space, achieving separation and contact without increasing the overall longitudinal size.
3Device complexity
If a simple structure is used for separation and contact, then the device complexity is reduced, but the reliability of separation and contact may be compromised
Solution Approach 1:
The patent applies local quality by giving the cam member's contact portion specific frictional properties that enable reliable engagement with the photoreceptor drum. The contact portion is designed with appropriate surface characteristics to generate sufficient frictional force for dependable separation and contact, while the rest of the cam member maintains a simple structure. This localized functional differentiation ensures reliability without overall structural complexity.
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 cam member configuration simplifies the structure, allows for efficient separation and contact of the charging roller with the photoreceptor drum, and prevents the process unit from becoming larger in the longitudinal direction, while ensuring reliable operation and easy manual switching.
Implementation Method 1
the charging roller is switched from the separate state to the contact state by rotating the cam member in a normal direction dependently with rotation of the photoreceptor drum in a normal direction due to frictional force between the drum main body and the contact portion
Data Source
AI summary
A process unit includes a photoreceptor drum, a charging roller, and a cam member. The cam member includes a mounting portion that externally fits to a shaft portion of the charging roller and a contact portion that protrudes to an outside of the mounting portion. Then, the charging roller is maintained in a separate state by bringing the contact portion of the cam member into contact with an outer surface of the drum main body, and the charging roller is switched to a contact state by rotating the cam member dependently with rotation of the photoreceptor drum in a normal direction.