Developing Roller Coupling Structure for Uniform Rotation Transfer
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face challenges in preventing rotation unevenness of the developing roller due to gear-to-gear drive connections, and require complex mechanisms for coupling retraction and engagement to transmit rotational force effectively.
Innovation Solution
A developing cartridge with a coupling member that receives rotational force from the main assembly, featuring a resilient material and a unique gear structure that allows for stable and accurate transmission of rotational force to the developing roller, while enabling easy mounting and demounting, and minimizing stress on the coupling mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gear-to-gear drive connection is used between the main assembly and the developing device, then the rotational force can be transmitted, but rotation unevenness of the developing roller cannot be prevented
Solution Approach 1:
The patent introduces a coupling member as an intermediary component between the drive shaft and the developing device. This coupling member includes a coupling protrusion that engages with a coupling recess, replacing the direct gear-to-gear connection. The intermediary coupling mechanism transmits rotational force more smoothly, preventing rotation unevenness while maintaining a relatively simple device structure.
Solution Approach 2:
The patent replaces the traditional gear-to-gear mechanical drive system with a coupling-based drive system. The coupling member uses a protrusion-recess engagement mechanism instead of gear teeth meshing, which eliminates the rotation unevenness caused by gear transmission while keeping the mechanical structure simple and reliable.
2Ease of operation
If the main assembly side coupling is retracted to avoid interference with the developing rotary member movement, then the coupling can be connected, but a moving mechanism such as a solenoid is required
Solution Approach 1:
The coupling member is designed to automatically engage and disengage without requiring external moving mechanisms. The coupling protrusion and recess are positioned such that they naturally align and connect when the developing cartridge is mounted, and automatically disconnect when removed. This self-service mechanism eliminates the need for solenoids or other active moving components, simplifying the device while maintaining ease of operation.
3Productivity
If a gear provided in the main assembly and a gear provided in the developing cartridge are engaged, then the developing roller can be rotated, but it is difficult to prevent rotation unevenness
Solution Approach 1:
The coupling member serves as an intermediary between the drive shaft and the developing roller, replacing the direct gear engagement. This intermediary transmission method provides smoother rotational force delivery, maintaining developing efficiency while eliminating the rotation unevenness inherent in gear-to-gear connections.
Data Source
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AI summary
A developing device (B) usable with an electrophotographic image forming apparatus (100), said apparatus including a driving shaft (180) rotatable having a rotating force applying portion (182) and not movable in a direction substantially perpendicular to an axial direction of said driving shaft, and a rotatable rotary (130a), said developing device being movable in a direction substantially perpendicular to an axial direction of the driving shaft in response to rotation of said rotary with said developing device mounted to said rotary, said developing device including i) a developing roller (110) for developing an electrostatic latent image formed on an electrophotographic photosensitive member drum (107); ii) a developer accommodating portion (116) for accommodating a developer for use by said developing roller to developing the electrostatic latent image; iii) a coupling member (150) for transmitting a rotating force to said developing roller in a state that developing cartridge is mounted to said rotary, said coupling member including a rotating force receiving portion (150a) for engaging with the rotating force applying portion to receive said driving shaft the rotating force from the driving shaft and a projection (150j) at a trailing end which is opposite from said rotating force receiving portion; iv) a regulating member (160) including a regulating portion (160b1) for regulating said coupling member at a pre-engagement angular position before engagement with the driving shaft by contacting with said projection, and including a permitting portion (160b2) for permitting said coupling member to revolve substantially; v) an elastic member (159) for elastically urging said coupling member to position said coupling member at the regulating portion, wherein when said rotary rotates, said coupling member moves from the pre-engagement angular position to a rotational force transmitting angular position in response to movement of said coupling member from the regulating portion to the permitting portion against an elastic force of said elastic member by said coupling member contacting said driving shaft member with movement of said developing device, and when said rotary further rotates, said coupling member moves from the rotational force transmitting angular position to a disengaging angular position to disengage said coupling member from the driving shaft against an elastic force of said elastic member.