Variable-Speed Feeding Screw for Toner Dispersion in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses with two-component developing devices face challenges in maintaining an optimal ratio of toner to carrier, leading to insufficient stirring of toner, which results in image contamination and poor image quality due to agglomerated toner particles.
Innovation Solution
An image forming apparatus with a toner supplying system that includes a feeding screw and a controller to adjust the rotational speed based on the number of rotations, ensuring proper toner dispersion by varying the rotational speed between a first and second speed depending on the determined number of rotations, thereby improving toner stirring and reducing image contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the supplying screw rotates at high speed to quickly supply toner, then the productivity is improved, but the stirring property of the supplied toner becomes insufficient
Solution Approach 1:
The supplying screw rotates at different speeds in different time periods: at a first rotational speed when the number of rotations is at the first integer of times of rotation, and at a second rotational speed slower than the first rotational speed when the number of rotations is at a second integer of times of rotation smaller than the first integer of times of rotation. This periodic variation in rotation speed ensures both quick toner supply and adequate stirring.
Solution Approach 2:
The rotational speed of the supplying screw is made variable rather than constant. The controller dynamically adjusts the rotational speed based on the determined number of rotations, switching between first and second rotational speeds to optimize both supply efficiency and stirring effectiveness.
2Manufacturing precision
If the toner is supplied quickly to maintain the toner-to-carrier ratio, then the manufacturing precision is improved, but the toner dispersion becomes insufficient leading to agglomeration
Solution Approach 1:
By periodically varying the rotation speed of the supplying screw between first and second speeds based on the rotation count, the system achieves both precise toner supply control and adequate dispersion, preventing agglomeration while maintaining the optimal toner-to-carrier ratio.
Solution Approach 2:
The supplying screw continues to rotate throughout the toner supply process, but with variable speed. This continuous action with speed modulation ensures that toner is supplied continuously to maintain the ratio while also being adequately dispersed to prevent agglomeration.
Data Source
AI summary
An image forming apparatus includes a controller to control a driving device such that a rotational speed of a supplying and feeding screw when it is rotated a predetermined number of times to supply developer to a developing device in a predetermined amount during execution of a continuous image forming job on a plurality of first recording materials is a first rotational speed, and a rotational speed of the supplying and feeding screw when it is rotated the predetermined number of times to supply the developer in the predetermined amount during execution of a continuous image forming job on a plurality of second recording materials is a second rotational speed slower than the first rotational speed. The second recording materials have a length longer than the first recording materials with respect to a sub-scan direction.