Supplying Roller Air Permeation Gradient for Toner Flow Stability
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Solution Overview
Problem
The existing developing devices in electrophotographic image forming apparatuses experience toner clogging and reduced motion in the developing chamber, leading to image defects such as improper toner followability and lateral bands due to variations in air permeation and deformation of the supplying roller, especially when stored for long periods.
Innovation Solution
The supplying roller is designed with a larger air permeation amount in the central portion than the end portions, and a manufacturing method involving a central sponge roller with a higher air permeation amount and end sponge rollers with lower permeation amounts, supported by the frame, to maintain consistent toner supply and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the air permeation amount of the supplying roller is increased to improve toner circulation, then toner supply performance is improved, but the supplying roller deforms when stored for long periods causing image defects
Solution Approach 1:
The supplying roller is designed with non-uniform air permeation distribution along its longitudinal direction. The central portion has a first air permeation amount while the end portions have a second air permeation amount that is 70% or less of the first. This local quality differentiation allows the central portion to provide sufficient toner circulation while the stiffer end portions resist deformation during storage.
2Productivity
If the supplying roller has high air permeation in the central portion to improve toner supply, then toner incorporation is improved, but lateral bands occur due to deformation
Solution Approach 1:
The supplying roller implements local quality by creating a gradient in air permeation properties along its length. The central portion with higher air permeation (first air permeation amount) ensures adequate toner supply, while the end portions with lower air permeation (second air permeation amount ≤70% of first) maintain structural rigidity to prevent the lateral band defects that would otherwise occur.
3Ease of operation
If the supplying roller is made softer to improve toner incorporation, then toner supply efficiency increases, but the roller deforms under its own weight during storage
Solution Approach 1:
The supplying roller applies local quality principles by differentiating the mechanical properties along its longitudinal axis. The central portion has softer characteristics with higher air permeation for effective toner incorporation, while the end portions have harder characteristics with lower air permeation (70% or less of the central portion) that provide structural support and prevent deformation under gravitational force during storage.
Solution Approach 2:
The supplying roller is segmented into functionally distinct regions along its longitudinal direction: a central region with first air permeation properties and end regions with second air permeation properties. This segmentation allows each region to perform its specific function - the central region for toner incorporation and the end regions for structural stability - thereby resolving the contradiction between softness and shape retention.
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 design enhances toner circulation and prevents image defects by maintaining consistent toner supply and reducing deformation, ensuring uniform image quality even after long-term storage.
Implementation Method 1
the supplying roller is larger in absolute value of an air permeation amount in a central portion with respect to the longitudinal direction than in a position of 1/10 of a length of the supplying roller in the longitudinal direction from the end portion
Data Source
AI summary
A developing device includes a developer carrying member, a supplying roller, an accommodating chamber, a developing chamber, a development opening, a stirring shaft, and a stirring member. In an attitude in which the developing device is mounted in an image forming apparatus and opposite end portions of the supplying roller with respect to a longitudinal direction of the supplying roller are supported by a frame of the image forming apparatus, the development opening is provided above a rotation axis of the supplying roller, the stirring shaft is provided above the development opening, and the supplying roller is larger in absolute value of an air permeation amount in a central portion thereof with respect to the longitudinal direction than in a position of 1/10 of a length thereof from the end portion thereof.