Developing Cartridge Contact Arrangement for Frame Stability
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Solution Overview
Problem
Conventional developing roller contact/separation configurations in electrophotographic image forming apparatuses lead to deformation of the developing roller, affecting image quality, and result in an undesired inclination of the developing frame due to pressure from multiple electric contacts, compromising stable electric power supply.
Innovation Solution
The configuration of the developing cartridge positions the developing unit side electric contact points to form a polygon with the axis of rotation as its center, ensuring symmetric force application and reducing the inclination of the developing frame, thereby stabilizing the electric power supply and minimizing sliding resistance during contact/separation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multiple electric contacts are disposed at one end of the process cartridge, then electric power supply is achieved, but the developing frame becomes inclined due to pressure from the contacts
Solution Approach 1:
The patent applies asymmetry by intentionally positioning the electric contacts and pivot center at different locations along the longitudinal axis of the developing frame. This asymmetric arrangement allows the pressure from multiple electric contacts at one end to be compensated by the geometric configuration, preventing the developing frame from becoming inclined while maintaining stable electric power supply to all process means.
2Productivity
If the developing roller remains in contact with the photosensitive drum for prolonged periods, then image formation continues, but the developing roller deforms affecting image quality
Solution Approach 1:
The patent implements periodic action by designing the developing roller to alternately contact and separate from the photosensitive drum. The roller contacts the drum during image formation periods and separates during non-image formation periods, preventing prolonged contact that would cause deformation while maintaining productivity when images need to be formed.
3Manufacturing precision
If the developing roller is separated from the photosensitive drum at other times, then deformation is suppressed, but contact/separation operation complexity increases
Solution Approach 1:
The patent applies dynamics by making the developing roller's contact state with the photosensitive drum variable rather than fixed. The roller dynamically transitions between contact and separation states based on operational requirements, allowing deformation suppression during separation while maintaining simple operation through automatic or controlled state transitions.
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 suppresses the inclination of the developing frame, ensuring stable electric power supply and improved image quality by maintaining consistent pressure on the developing roller, reducing sliding resistance, and enhancing the overall operational stability of the image forming apparatus.
Implementation Method 1
under elastic force of a spring (omitted from illustration) provided to the developing frame
Implementation Method 2
an electroconductive elastic member, of which a metal spring provided to the image forming apparatus is representative, comes into contact with an electroconductive contact portion provided to the process cartridge at a predetermined pressure, thereby securing a conduction path
Implementation Method 3
The developing roller comes into contact with the photosensitive drum, thereby developing an electrostatic latent image formed on the photosensitive drum
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A developing device (4), detachably mountable to an image forming apparatus main body (100A), includes a developing frame (31), a developing roller (25), and electric contact points (44, 45, 46, 47, 48) disposed at one end in an axial direction of the developing roller (25). The developing device (4) is pivotably centered on a pivot axis (Y) parallel to the axial direction of the developing roller (25), and electrically conducts with the image forming apparatus main body (100A) via the electric contact points (44, 45, 46, 47, 48) when mounted. In a plane perpendicular to the axial direction of the developing roller (25), a position of the pivot axis (Y) is within a polygon having a greatest area formed of outer shapes of the electric contact points (44, 45, 46, 47, 48) and straight lines connecting the outer shapes of the electric contact points (44, 45, 46, 47, 48).