Developing Device Toner Carrier Discharge Prohibition
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Solution Overview
Problem
In image forming apparatuses using the two-component development method, the degradation of toner carriers leads to a decrease in charge ability, resulting in lower image quality due to the discharge of new toner carriers before they can replace degraded ones, causing an increase in the ratio of degraded toner carriers and potential fogging issues.
Innovation Solution
A developing device with a developer container, conveyance screws for circulating the developer, a supply unit for toner carrier replenishment, and a discharge unit that includes a discharge prohibiting mechanism to prevent the premature discharge of new toner carriers during a predetermined period, ensuring efficient replacement and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the trickle development method is used to discharge excessive developer while supplying new toner carrier, then the developer circulation is maintained, but the new toner carrier is discharged prematurely causing increased ratio of degraded toner carrier and lower image quality
Solution Approach 1:
The discharge prohibiting unit is activated in advance during the toner carrier supply period to prevent premature discharge. By prohibiting discharge before the new toner carrier can be properly integrated into the circulation path, the system ensures that fresh toner carriers remain in the system long enough to replace degraded ones, thereby maintaining image quality while enabling effective toner carrier replacement.
2Productivity
If new toner carrier is supplied continuously without discharge prohibition, then the developer circulation continues smoothly, but the ratio of degraded toner carrier increases over time reducing charge ability
Solution Approach 1:
The system activates the discharge prohibiting unit in advance during the toner carrier supply period to prevent premature discharge. This preliminary action ensures that new toner carriers remain in the circulation path long enough to replace degraded ones, maintaining charge ability while preserving circulation efficiency.
Solution Approach 2:
The discharge prohibition is applied periodically during specific supply periods when new toner carrier is being introduced. This periodic control allows the system to maintain smooth circulation during normal operation while periodically preventing discharge to ensure proper integration of fresh toner carriers, thereby balancing productivity and reliability.
3Reliability
If discharge prohibition period is set longer, then more new toner carrier is retained preventing fogging, but the excessive developer discharge is delayed
Solution Approach 1:
The system dynamically adjusts the discharge prohibition period parameter based on the toner carrier supply rate and circulation characteristics. By optimizing this time parameter, the system retains enough new toner carriers to prevent fogging while minimizing the delay in excessive developer discharge, achieving a balance between reliability and time efficiency through parameter optimization.
Data Source
AI summary
A developing device according to the invention develops latent images formed on an image carrier with a developer including toner carrier and toner. The developing device includes a developer container, a developer conveying member, a supply unit, a discharge unit, and a discharge prohibiting unit. The developer container contains the developer. The developer conveying member conveys the developer contained in the developer container as stirring the developer to circulate the developer in a circulation path in the developer container. The supply unit supplies at least the toner carrier to the circulation path. The discharge unit discharges excessive developer in the circulation path according to supply from the supply unit. The discharge prohibiting unit prohibits discharge of the developer from the discharge unit during a predetermined discharge prohibiting period in a case where the toner carrier is supplied from the supply unit.