Developing Device Cover Gap Segmentation for Toner Scattering
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Solution Overview
Problem
Existing developing devices in image forming apparatuses, such as copiers and printers, face insufficient prevention of toner scattering due to inadequate suction airflow management, leading to internal pressure increases and further toner scattering issues.
Innovation Solution
The developing device incorporates a sheet member cantilevered by the cover, with a large gap portion and a small gap portion, forming first and second gaps respectively, to manage suction airflow effectively, minimizing toner scattering by stabilizing airflow and preventing pressure increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a suction airflow is generated in the gap between the developing roller and the cover to prevent toner scattering, then toner scattering is reduced, but the internal pressure of the developing device increases causing further toner scattering
Solution Approach 1:
The cover is divided into multiple sections: a first cover section with a first gap for suction airflow generation, a second cover section with a second gap for pressure relief, and a third cover section. This segmentation allows simultaneous achievement of toner scattering prevention through suction while maintaining pressure balance to prevent further scattering.
Solution Approach 2:
Different regions of the cover are designed with different gap characteristics - the first gap is positioned and sized to generate effective suction airflow for toner control, while the second gap is positioned and sized to provide pressure relief. This local differentiation of gap properties resolves the contradiction between needing suction and avoiding pressure buildup.
2Object-affected harmful factors
If the gap between the developing roller and the cover is reduced to improve toner containment, then toner scattering is reduced, but the suction airflow effect is weakened
Solution Approach 1:
The cover gap is segmented into a first gap and a second gap. The first gap is designed with specific dimensions to generate strong suction airflow for preventing toner scattering, while the second gap provides pressure relief. This segmentation allows optimization of suction airflow speed without compromising toner containment.
Solution Approach 2:
Instead of simply reducing the gap size in one dimension, the solution adds a dimensional aspect by creating multiple gaps at different positions and orientations. The first gap is positioned to maximize suction effect, while the second gap is positioned for pressure balance, thereby maintaining suction airflow speed while preventing pressure-related scattering.
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 significantly reduces toner scattering by stabilizing airflow and preventing pressure increases within the developing device, ensuring efficient toner management and reduced scattering.
Implementation Method 1
a suction airflow into the developing device is generated in the gap due to a pump action
Data Source
Figure 1
Figure 2~3(b)
Figure 4~5
AI summary
A developing device includes a developing roller (13a) to rotate in a predetermined direction of rotation and opposed to or in contact with an image bearer (11) to form a development range, a cover (13r) to cover the developing roller (13a) downstream from the development range, a sheet member (13s) cantilevered by the cover (13r) to contact the developing roller (13a) with a flat face of the sheet member (13s) while trailing along the predetermined direction of rotation at a position downstream from the development range. The cover (13r) includes a large gap portion (13r2) to form a first gap in a first predetermined range and a small gap portion (13r1) disposed adjacent to and downstream from the large gap portion (13r2) to form a second gap (H) smaller than the first gap, in a second predetermined range in the predetermined direction of rotation.