Toner Buffer Unit Control for Stable Feeding
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face challenges in maintaining stable toner feeding, leading to decreased image quality due to overfeeding or underfeeding of toner, and require multiple motors which increase size and cost.
Innovation Solution
An electrophotographic image forming apparatus with a toner buffer unit that includes an agitating member and carrying members, controlled by a unit that selectively drives the members to prevent overfeeding and ensure adequate toner supply using a single motor, incorporating a one-way clutch for efficient toner transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the agitating member and carrying member are driven by separate motors to prevent overfeeding of toner, then the toner feeding stability is improved, but the number of motors is doubled, increasing size and price
Solution Approach 1:
The patent applies dynamics by enabling the single motor to selectively drive either the agitating member or the carrying member based on operational modes. The motor transitions between different driving states: driving only the agitating member for toner supplementation, driving both members for normal operation, and controlling the carrying member to prevent overfeeding. This dynamic control resolves the contradiction by achieving reliable toner feeding stability through intelligent motor control rather than requiring multiple motors.
2Quantity of substance
If the carrying member is continuously driven to feed toner to the developer, then the toner supply is maintained, but the toner concentration in the developer exceeds the reference concentration, decreasing image quality
Solution Approach 1:
The patent implements feedback control by monitoring the toner concentration in the developer and adjusting the carrying member's driving accordingly. When the toner concentration reaches or exceeds the reference concentration, the control unit stops driving the carrying member to prevent overfeeding. This feedback mechanism ensures accurate toner concentration control while maintaining adequate toner supply, resolving the contradiction between quantity supply and precision control.
Solution Approach 2:
The patent applies periodic action by intermittently driving the carrying member based on toner concentration levels rather than continuous operation. The carrying member is driven periodically to supplement toner when concentration drops below the reference level and stopped when the reference is reached. This periodic driving pattern maintains adequate toner supply while preventing overfeeding, achieving both quantity maintenance and concentration precision.
3Reliability
If a toner buffer unit is introduced between the toner cartridge and developer, then the toner feeding control is improved, but the device size and complexity increase
Solution Approach 1:
The patent applies merging by integrating the toner buffer unit's functions into the existing developer assembly rather than adding a completely separate buffer system. The buffer unit is positioned within the developer housing and shares structural space with other developer components. This merged design achieves improved toner feeding control through the buffer mechanism while minimizing the increase in overall device size by utilizing existing spatial arrangements.
Data Source
AI summary
An eletrophotographic image forming apparatus may include a developing unit; a toner buffer unit which feeds a toner to the developing unit, and includes an agitating member agitating the toner contained inside the toner buffer unit and a first carrying member carrying the toner contained inside the toner buffer unit to the developing unit; a toner cartridge which feeds the toner to the toner buffer unit, and includes a second carrying member carrying the toner contained inside the toner cartridge to the toner buffer unit; and a control unit which controls a first driving unit driving the second carrying member and a second driving unit driving the agitating member and the first carrying member, and the control unit includes a first feed mode, a second feed mode and a toner supplement mode.