Transfer Bias Control for Image Quality in High Humidity
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Solution Overview
Problem
In image forming apparatuses, particularly under high-humidity environments, reducing the transfer bias to prevent excessive current flow leads to insufficient toner transfer, affecting image quality, while consistently lowering the charging bias to prevent this issue causes difficulties in collecting residual developers, resulting in image formation problems.
Innovation Solution
An image forming apparatus with a photosensitive member, a charging member, a developer carrier, and a transfer member, where the transfer control unit adjusts the transfer bias to a first or second value, and the charging control unit adjusts the charging bias accordingly, ensuring minimal residual toners are not collected by the developer carrier, thereby maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transfer bias is reduced to prevent excessive current flow under high-humidity environments, then current flow control is improved, but toner transfer efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the transfer bias adjustable rather than fixed. The control unit dynamically switches between a first transfer bias (for normal conditions) and a second transfer bias (for high-humidity conditions), allowing the system to adapt to changing environmental conditions and resolve the contradiction between current flow control and toner transfer efficiency
Solution Approach 2:
The patent changes the parameter of transfer bias based on humidity detection. When humidity is detected to be high, the control unit changes the transfer bias from the first value to the second value, thereby preventing excessive current flow while maintaining acceptable toner transfer efficiency through parameter adjustment
2Manufacturing precision
If the charging bias is lowered to prevent toner transfer issues, then toner transfer is improved, but developer collection by the developing roller deteriorates
Solution Approach 1:
The patent applies dynamics by making the charging bias adjustable rather than fixed. The control unit dynamically switches between a first charging bias (for normal conditions) and a second charging bias (for high-humidity conditions), allowing the system to adapt to changing environmental conditions and resolve the contradiction between toner transfer quality and developer collection efficiency
Solution Approach 2:
The patent changes the parameter of charging bias based on humidity detection. When humidity is detected to be high, the control unit changes the charging bias from the first value to the second value, thereby preventing toner transfer issues while maintaining developer collection through parameter adjustment
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 configuration minimizes uncollected developers and maintains image quality by adjusting biases in response to humidity conditions, allowing for effective toner transfer and collection, even under high-humidity environments.
Implementation Method 1
a charging member that charges the photosensitive member
Implementation Method 2
a transfer member that transfers the developers on the photosensitive member to a transfer medium by nipping the transfer medium between the photosensitive member
Data Source
AI summary
An image forming apparatus including: a photosensitive member; a charging member; a developer carrier; a transfer member; a charging control unit that applies a charging bias having the same polarity as a charged polarity of the developers to the charging member; and a transfer control unit that applies a transfer bias having a reverse polarity to the charged polarity of the developers to the transfer member, wherein when the transfer control unit sets the absolute value of the transfer bias to a first value, the charging control unit sets an absolute value of the charging bias to a third value, and wherein when the transfer control unit sets the absolute value of the transfer bias to a second value, the charging control unit sets the absolute value of the charging bias to a fourth value smaller than the third value.