Developing Roller Voltage Control for Toner Exudation
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Solution Overview
Problem
In image forming apparatuses, prolonged standing of toner supply rollers and developing rollers leads to exudation of ionic conducting agents and foam stabilizing agents, causing image defects such as lateral streaks and fogging, which existing methods struggle to suppress effectively.
Innovation Solution
An image forming apparatus with a control unit that manages voltage differences between the developing member and the developer supply member to control the rotational operations, including a first rotational operation with a smaller potential difference for scraping off adhering components and a second rotational operation with a higher potential difference for relocating them, thereby reducing image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of ionic conducting agent added to the toner supply roller is increased to suppress resistance change during prolonged use, then the reliability is improved, but the exudation of ionic conducting agent increases causing image defects
Solution Approach 1:
The patent applies a preliminary rotational operation before actual image forming to scrape off exuded components from the developing roller surface. This preliminary action removes the harmful exudation that occurs during prolonged standing, preventing image defects while allowing the toner supply roller to maintain sufficient ionic conducting agent for reliable operation.
2Ease of operation
If the toner supply roller and developing roller are left standing for prolonged periods, then the device complexity is reduced by not requiring continuous operation, but components are exuded causing image defects
Solution Approach 1:
The system performs a preliminary rotational operation when the developing apparatus is first used after prolonged standing. This preliminary action activates the toner supply and scraping mechanisms to remove exuded components before actual image forming begins, enabling the system to maintain ease of operation with standby capability while preventing exudation-related defects.
3Manufacturing precision
If a rotational operation is performed to scrape off adhering components, then the image quality is improved, but the device complexity increases due to additional operational modes
Solution Approach 1:
The patent merges the preliminary rotational operation with the existing cleaning operation. The same toner supply roller and developing roller that perform cleaning also perform the preliminary scraping function. This combines multiple functions into existing components, improving image quality while minimizing the increase in device complexity.
4Stability of the object's composition
If the first voltage applying unit and second voltage applying unit are controlled to create different potential differences, then the toner distribution is improved, but the control complexity increases
Solution Approach 1:
The patent implements dynamic voltage control where the first voltage applying unit applies a first voltage during the preliminary rotational operation and a second voltage during actual image forming. The control unit dynamically adjusts the potential difference between the developing roller and toner supply roller based on the operational phase, improving toner distribution while managing control complexity through phase-based switching.
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
The solution effectively suppresses image defects like lateral streaks and fogging by ensuring proper toner distribution and removal, maintaining image quality even after prolonged standing periods.
Implementation Method 1
a first voltage applying unit configured to apply a first voltage to the developing member; a second voltage applying unit configured to apply a second voltage to the developer supply member... a first potential difference is formed between the developing member and the developer supply member... a second voltage difference is formed between the developing member and the developer supply member
Data Source
AI summary
An image forming apparatus includes an image bearing member, a developing member that supplies a developer of a regular polarity, a developer supply member that supplies developer to the developing member, and a control unit that applies a first voltage to the developing member and a second voltage to the developer supply member. The control unit executes an image forming operation, and a rotational operation in which the developer supply member rotates in a state in which the first voltage of a regular polarity is applied thereto. The rotational operation includes a first rotational operation in which a potential difference is a first potential difference and a second rotational operation in which the developing member and the developer supply member rotate in a state in which the second voltage having the same polarity as the regular polarity and having a greater absolute value is applied.