Charging Roller Separation Mechanism for Photosensitive Drum Load Control
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face issues with load distribution on the photosensitive drum when separating the charging roller, leading to potential deformation and damage due to uneven load application during the separation process.
Innovation Solution
The cartridge design incorporates first and second maintaining members on the charging roller and corresponding moving portions on the image bearing member to control the movement of the charging roller from a separated state to a closer position, reducing the load applied to the photosensitive drum by optimizing the separation timing and position of the separation members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separation members on both end portions of the charging roller are configured to release the separated state simultaneously when the photosensitive drum is rotated, then the charging roller can be brought into contact with the photosensitive drum efficiently, but a large load is applied to the photosensitive drum in the direction opposite to rotation
Solution Approach 1:
The patent divides the separation release function into two independent members: a first separation member on one end portion of the charging roller and a second separation member on the other end portion. These members operate at different timings during drum rotation, with the first member releasing before the second member. This segmentation allows the load to be distributed sequentially rather than simultaneously, reducing the peak torque applied to the photosensitive drum while maintaining efficient contact establishment.
2Reliability
If the charging roller is kept separated from the photosensitive drum during delivery and storage, then material deformation and deterioration are prevented, but additional mechanisms are needed to control the separation state
Solution Approach 1:
The patent incorporates maintaining members that automatically maintain the charging roller in a separated position from the photosensitive drum during delivery and storage before use. This preliminary action ensures the roller remains separated during critical periods when material stability is most vulnerable, preventing deformation and deterioration. When the cartridge is installed and the drum rotates, the separation members automatically release the separated state at appropriate timings, eliminating the need for manual intervention or complex external control mechanisms.
Data Source
AI summary
A cartridge includes a first maintaining member and a second maintaining member, each disposed on respective end portions of a charging roller in an axial direction of the charging roller and configured to maintain a position of the charging roller at a first position, and a first moving portion and a second moving portion, each disposed on respective end portions of an image bearing member in an axial direction of the image bearing member and configured to respectively abut on and move the first and second maintaining members according to rotation of the image bearing member so as to move the charging roller from the first position to the second position. When the image bearing member is rotated in which the charging roller is in the first position, the first moving portion abuts on the first maintaining member, and then the second moving portion abuts on the second maintaining member.