Developing Sleeve End Protection for Toner Dispersion Control
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Solution Overview
Problem
Conventional developing devices with grooved or sandblasted surfaces on the developing sleeve experience issues with developer density fluctuations, leading to increased pressure and potential sticking or dropping of developer at the ends, causing photoreceptor damage, background contamination, and banding, especially when using small-diameter particles and tight developing gaps.
Innovation Solution
A developing device with a shock-absorbing member and toner dispersion prevention sheet is implemented at both ends of the developing sleeve, where the outer diameter is smaller than the center portion, to prevent damage and maintain consistent developer supply, using a side protection sheet and toner dispersion prevention sheet to absorb shocks and prevent toner dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the outer diameter of the developing sleeve is reduced at both ends to prevent developer sticking, then developer density fluctuation is reduced, but the photoreceptor may be damaged due to contact with the tapered ends
Solution Approach 1:
The protective function is segmented from the developing sleeve structure by adding separate protection sheets at the end portions. These protection sheets are independently attachable components that provide shock absorption without requiring modification to the developing sleeve's cylindrical structure, thus maintaining uniform developer density while protecting the photoreceptor.
Solution Approach 2:
The protection sheet acts as an intermediary element between the developing sleeve and the photoreceptor. It absorbs shocks and prevents direct contact between the tapered end portions of the developing sleeve and the photoreceptor surface, thereby eliminating the damage risk while allowing the tapered structure to remain for developer density control.
2Object-affected harmful factors
If a shock-absorbing member is added to protect the photoreceptor, then photoreceptor damage is prevented, but the device complexity increases
Solution Approach 1:
The protection sheet is implemented as a thin, flexible film with shock-absorbing properties. This thin-film approach provides effective photoreceptor protection without adding significant structural complexity or volume to the developing device, maintaining simplicity while achieving the protective function.
Solution Approach 2:
The protection sheet is made from composite material that combines shock absorption capability with thin-film characteristics. This allows the protective function to be achieved in a single, integrated sheet that does not require complex multi-layer construction or assembly procedures.
Data Source
AI summary
A developing device includes a developer bearing member and a shock absorbing member. The developer bearing member includes a developing region across from an image bearing member including an image forming region, and a center portion including an image creating region corresponding to the image forming region on the image bearing member. The developer bearing member is configured to bear the developer on the surface thereof and transport the developer to the developing region while moving the surface. The shock absorbing member is provided to each of both ends of the developer bearing member in a width direction thereof across from the image bearing member. Each of both ends of the developer bearing member is provided outside the center portion of the developer bearing member, and an outer diameter of each of both ends of the developer bearing member is substantially smaller than an outer diameter of the center portion.