Developer Distribution Control in Image Forming Apparatus
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Solution Overview
Problem
Existing developing apparatuses face challenges in preventing the formation of toner layers upstream of the regulating blade during non-image forming operations, leading to conveyance failures and uneven developer distribution between supply and recovery chambers, resulting in excessive discharge or overflow issues.
Innovation Solution
A developing apparatus with a control mechanism that adjusts the rotational speeds of the conveying portion and developer carrier, increasing the ratio of rotational speeds during non-image forming operations to redistribute the developer, ensuring the toner layer is minimized and preventing overflow by circulating the developer between chambers at predetermined speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotational speeds of the conveying portion and developer carrier are maintained at normal operating ratios during non-image forming operations, then the developer circulation continues at standard rates, but toner layers form upstream of the regulating blade causing conveyance failures
Solution Approach 1:
The patent applies periodic action by switching between different rotational speed ratios based on operational mode. During non-image forming operations, the control unit increases the rotational speed ratio above the normal operating ratio to prevent toner layer formation, then returns to the normal ratio when image forming resumes. This periodic adjustment of operational parameters effectively eliminates the harmful toner layer accumulation while maintaining reliable developer conveyance.
2Reliability
If the rotational speed ratio is increased during non-image forming operations to prevent toner layer formation, then conveyance reliability improves, but developer distribution becomes uneven between supply and recovery chambers
Solution Approach 1:
The control unit implements periodic action by temporarily increasing the rotational speed ratio only during non-image forming operations, then returning to the normal operating ratio when image forming resumes. This time-dependent adjustment allows the system to prevent toner layer formation during idle periods while restoring proper developer distribution uniformity when image forming begins, effectively resolving the contradiction between conveyance reliability and distribution stability.
3Object-generated harmful factors
If the rotational speed ratio is increased to redistribute developer during non-image forming operations, then toner layer formation is prevented, but excessive discharge or overflow occurs
Solution Approach 1:
The control unit applies periodic action by dynamically adjusting the rotational speed ratio based on operational mode. During non-image forming operations, it temporarily increases the ratio to prevent toner layer formation, then returns to the normal operating ratio when image forming resumes. This controlled, time-limited adjustment prevents both toner layer formation and excessive developer discharge by ensuring the high ratio is applied only when necessary.
4Stability of the object's composition
If the rotational speeds are adjusted to maintain even developer distribution, then overflow is prevented, but toner layers still form upstream of the regulating blade
Solution Approach 1:
The control unit implements periodic action by switching between different rotational speed ratios based on operational mode. During non-image forming operations, it increases the rotational speed ratio above the normal operating ratio to actively prevent toner layer formation, then returns to the normal ratio when image forming resumes. This dynamic adjustment ensures that developer distribution remains stable during image forming while effectively preventing toner layer accumulation during idle periods.
Data Source
AI summary
An image forming apparatus includes an image forming portion configured to form an image on a recording media and including a developer bearing member configured to bear developer and carry the developer, a regulating portion disposed opposite to the developer bearing member and configured to regulate an amount of the developer on the developer bearing member, a first chamber configured to supply the developer to the developer bearing member, and a second chamber configured to communicate with the first chamber to form a circulating route of the developer. In addition, a first feeding member feeds the developer in the first chamber, and a second feeding member feeds the developer in the second chamber. A control portion executes, in a non-image forming state, a mode of driving the developer bearing member in a condition in which the first feeding member is stopped.