Developing Roller Voltage Switching for Toner Circulation
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Solution Overview
Problem
As the capacity of the developing device increases, toner around the developing roller and supplying roller becomes compacted, leading to poor circulation and difficulty in discharging toner, resulting in image defects due to insufficient peeling off by the supplying roller.
Innovation Solution
An image forming apparatus with a control portion that alternately switches a first and second potential difference between the developing and supplying members during non-image formation based on toner amount information, performing a preliminary operation to prevent toner peeling issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacity of the developing device is enlarged to increase toner amount, then the toner accommodation capacity is improved, but the toner circulation becomes poor and peeling off becomes insufficient
Solution Approach 1:
The patent applies periodic action by alternately switching between a first potential difference (during which the supplying roller supplies toner to the developing roller) and a second potential difference (during which the supplying roller peels off toner from the developing roller). This periodic potential difference switching creates alternating supply and peeling-off cycles, ensuring that toner is both supplied and properly removed even when the developing device capacity is enlarged, thereby preventing poor circulation and peeling-off insufficiency.
2Quantity of substance
If the toner amount in the developing device is increased, then the developing device capacity is improved, but the toner circulation becomes compacted and discharge becomes difficult
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the potential difference between the supplying roller and developing roller. When the developing device capacity is enlarged causing compacted toner state, the control portion switches the potential difference between a first potential difference (for supply) and a second potential difference (for peeling off). This parameter switching optimizes toner circulation efficiency by ensuring proper electrical conditions for both supply and discharge, preventing compacted toner from becoming difficult to discharge.
3Manufacturing precision
If the supplying roller peels off toner from the developing roller, then the image quality is improved, but the peeling off becomes insufficient when developing device capacity is enlarged
Solution Approach 1:
The patent applies periodic action through alternating potential difference switching. During the first potential difference phase, the supplying roller supplies toner to the developing roller. During the second potential difference phase, the supplying roller peels off toner from the developing roller. This periodic switching ensures sufficient peeling-off action even when large toner amounts are accommodated, maintaining image quality by preventing toner accumulation on the developing roller.
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 solution effectively prevents image defects by ensuring proper toner circulation and discharge, maintaining image quality even with increased developing device capacity.
Implementation Method 1
between the developing roller and the supplying roller, a potential difference is provided
Data Source
AI summary
An image forming apparatus includes an image bearing member, a developing unit including a developing member and a supplying member, a developing voltage applying portion, a supplying voltage applying portion and a control portion. During non-image formation in a state in which the developing member and the supplying member rotate, the control portion is capable of controlling the developing voltage applying portion and the supplying voltage applying portion so as to perform a preliminary operation in which a first potential difference and a second potential difference different from the first potential difference are formed between the developing member and the supplying member by being alternately switched for a plurality of number of times based on toner amount information regarding a toner amount in the developing unit.