Developing Device Seal Members Prevent Toner Leakage
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Solution Overview
Problem
In image forming apparatuses like laser printers, the existing developing devices experience toner leakage due to the distortion of seal members caused by an inward force component in the rotational axis direction, leading to weakened contact pressure and improper sealing.
Innovation Solution
The developing device incorporates seal members with a base material formed of an elastic element and a sliding frictional member made of fibers, which contacts the circumferential surface of the roller main body, preventing distortion and ensuring proper toner sealing by maintaining contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sliding frictional member is affixed to the sponge member to form a side seal, then the seal member can prevent toner leakage, but the sliding frictional member bends under inward force causing the sponge member to distort and contact pressure to weaken
Solution Approach 1:
The seal member is divided into two functional layers: a sponge member (base material) that provides elastic support and maintains shape stability, and a sliding frictional member that provides toner release functionality. This segmentation allows each layer to specialize in its function without interfering with the other's structural integrity.
Solution Approach 2:
The side seal is constructed as a composite structure combining the sponge member (made from urethane foam) and the sliding frictional member (made of fibers). This composite design leverages the elastic properties of the sponge material to resist distortion while the fiber layer provides the necessary friction characteristics for toner handling.
2Stress or pressure
If the sponge member is compressed to produce elastic force for sealing, then sealing pressure is achieved, but the sliding frictional member bends and contacts the roller surface with reduced pressure
Solution Approach 1:
The sponge member is pre-compressed between the roller main body and the housing to establish a baseline elastic force before operation. This pre-compression ensures that the seal member maintains sufficient contact pressure with the roller surface, compensating for any subsequent bending of the sliding frictional member during operation.
Solution Approach 2:
The thickness of the sponge member is specifically designed to provide appropriate compression when the developing roller is attached to the housing. This parameter optimization ensures that the elastic force generated is sufficient to maintain seal integrity while accommodating the bending of the sliding frictional member.
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 effectively prevents toner leakage from the end portions of the developing roller by maintaining the integrity of the seal members, ensuring reliable toner transfer and image formation.
Implementation Method 1
a sliding frictional member which contacts with the circumferential surface of the roller main body such that the roller main body frictionally slides on the sliding frictional member
Implementation Method 2
the sponge member is compressed between the roller main body and the housing so as to produce an appropriate elastic force
Data Source
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AI summary
A developing device (27) according to an aspect of the invention includes: a housing (36); a developing roller (39) comprising a roller main body (52) having a circumferential surface, the developing roller (39) being rotatably supported to the housing (36); and seal members (91) respectively disposed to face both end portions of the circumferential surface of the roller main body (52) with respect to a rotational axis direction thereof and to press contact with the roller main body (52). Each of the seal members (91) comprises: a base material (92) formed of an elastic element; and a sliding frictional member (93) that is formed of fibers and contacts with the circumferential surface of the roller main body (52) such that the roller main body (52) frictionally slides on the sliding frictional member (93). Both edges of the circumferential surface of the roller main body (52) with respect to the rotational axis direction thereof are brought into contact with the base materials (92).