Toner Attachment Control via Dynamic Bias Reset in Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses face issues with excessive toner attachment to the developing roller, leading to reduced image quality due to varying environmental conditions and print duties, as the bias difference between the developing roller and toner supply roller voltages can result in excessive toner being transferred to areas outside the intended image area.
Innovation Solution
Implementing a reset operation processing unit that temporarily reduces the bias difference between the voltages applied to the developing roller and toner supply roller, allowing for a controlled toner supply and detachment, thereby preventing excessive toner accumulation on the developing roller and ensuring it does not attach to areas where images are not formed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a supply bias voltage is applied to the toner supply roller to generate a potential difference between the developing roller and the toner supply roller, then the amount of toner supplied to the developing roller is controlled and image density is adjusted, but excessive toner attaches to the developing roller and transfers to non-image areas, reducing image quality
Solution Approach 1:
The patent applies a reset operation that dynamically changes the bias voltage applied to the developing roller. During normal printing, a first bias voltage is applied for proper toner supply, but during reset operations (when no printing is performed), a second bias voltage with smaller absolute value is applied. This dynamic voltage adjustment prevents excessive toner attachment during idle periods while maintaining proper image density control during active printing.
Solution Approach 2:
The patent implements periodic reset operations between printing operations. During these reset periods, the bias voltage is reduced to prevent toner accumulation. This periodic switching between printing mode (first bias voltage) and reset mode (second bias voltage) creates a rhythm of toner supply and toner removal, preventing excessive attachment while ensuring image quality during actual printing.
2Quantity of substance
If the bias difference between developing roller and toner supply roller voltages is maintained for controlling toner supply, then image density is adjusted, but toner accumulates on the developing roller and adheres to non-image areas
Solution Approach 1:
The patent dynamically adjusts the bias voltage on the developing roller based on operational state. During printing operations, the first bias voltage maintains appropriate toner supply for image formation. During reset operations (no printing), the second bias voltage with smaller absolute value reduces toner attachment. This dynamic adjustment resolves the contradiction by adapting toner supply control to actual operational needs.
Solution Approach 2:
The patent changes the electrical parameter (bias voltage) of the developing roller based on operational mode. By switching between two distinct bias voltage levels (first bias voltage during printing, second bias voltage during reset), the system controls toner supply quantity appropriately for each state, preventing both insufficient and excessive toner attachment that would compromise image quality.
3Adaptability or versatility
If environmental conditions and print duties vary, then toner supply requirements change, but the fixed bias difference causes excessive toner attachment and image quality degradation
Solution Approach 1:
The patent makes the bias voltage dynamic rather than fixed. By detecting operational state (printing vs. reset), the system automatically switches between appropriate bias voltage levels. This dynamic adaptation allows the system to handle varying environmental conditions and print duties without excessive toner attachment, as the voltage is adjusted to match actual operational requirements.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit monitors operational state and adjusts the bias voltage accordingly. When printing is detected, the first bias voltage is applied; when no printing is detected (reset operation), the second bias voltage is applied. This feedback-based control ensures the system adapts to varying conditions while preventing harmful toner attachment.
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 reduces toner attachment on the developing roller by up to 20-40%, preventing toner from adhering to non-image areas and thereby enhancing image quality by maintaining optimal toner levels during printing operations.
Implementation Method 1
a supply bias voltage is applied to the toner supply roller to generate a potential difference between the developing roller and the toner supply roller
Data Source
AI summary
An image forming apparatus includes an image supporting member; a developer supporting member for attaching developer to a static latent image formed on a surface of the image supporting member; a developer layer forming member for forming a developer layer on the developer supporting member; a developer supply member for supplying developer to the developer supporting member; a developer supporting member voltage applying unit for applying a voltage to the developer supporting member; a developer supplying member voltage applying unit for applying a voltage to the developer supplying member; and a reset operation processing unit for setting a reset mode over a specific period of time, so that a bias difference in the reset mode between the voltage applied with the developer supporting member voltage applying unit and the voltage applied with the developer supplying member voltage applying unit becomes smaller than that in a printing mode.