Image Forming Apparatus Transfer Voltage Adjustment
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Solution Overview
Problem
Existing image forming apparatuses face issues with setting optimal secondary transfer voltages, leading to either excessive voltages causing 'white voids' or insufficient voltages resulting in low density, due to variations in density detection methods.
Innovation Solution
The apparatus sets multiple groups of test patterns with varying voltages and selects one group based on detection results to adjust the transfer voltage, ensuring stable density and preventing excessive transfer voltage settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high secondary transfer voltage is applied to ensure sufficient transfer density, then the density increases, but white voids occur due to excessive voltage
Solution Approach 1:
The patent segments the test voltage range into multiple groups (first group with lower voltages, second group with higher voltages) and selectively applies different evaluation methods to each group. This segmentation allows the system to search efficiently through the voltage range while avoiding excessive voltages that cause white voids, thus resolving the contradiction between achieving sufficient density and preventing image defects.
Solution Approach 2:
The patent changes the evaluation parameter from单纯 density to a combination of density and standard deviation. By using standard deviation to measure density uniformity, the system can detect white voids (which cause high variation) and adjust the voltage selection accordingly. This parameter change enables the system to avoid excessive voltages while ensuring sufficient transfer density.
2Object-affected harmful factors
If a low secondary transfer voltage is applied to avoid excessive voltage and white voids, then white voids are prevented, but density becomes insufficient
Solution Approach 1:
The patent implements feedback by measuring the density and standard deviation of test patches at different voltages, then using this information to select the optimal voltage. The system feeds back the evaluation results (density and uniformity) to adjust the voltage selection, ensuring that the chosen voltage provides sufficient density without causing white voids.
Solution Approach 2:
The patent makes the voltage selection dynamic by adjusting the evaluation criteria based on the measured standard deviation. When the standard deviation exceeds a threshold (indicating potential white voids), the system dynamically adjusts to select a lower voltage from the same group or switch to a different group, thus adapting to prevent white voids while maintaining sufficient density.
3Manufacturing precision
If multiple test voltages are applied sequentially from low to high to find optimal density, then sufficient density is achieved, but the risk of selecting excessive voltage increases
Solution Approach 1:
The patent segments the voltage search process into two phases: first searching within a lower voltage range (first group) to find a candidate voltage, then optionally expanding to higher voltages (second group) only if needed. This segmented approach reduces the risk of selecting excessive voltages while still allowing the system to achieve sufficient density when necessary.
Solution Approach 2:
The patent applies partial action by limiting the initial voltage search to a conservative range (first group) that is unlikely to cause white voids. Only if the density requirement is not met does the system perform excessive action by testing higher voltages (second group). This approach balances the need to achieve sufficient density with the need to avoid excessive voltage and its harmful effects.
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 approach effectively prevents excessive transfer voltage settings while maintaining sufficient transfer, thereby reducing image defects and ensuring consistent image quality.
Implementation Method 1
a sensor configured to detect, as density information, a density of the toner image formed on the recording medium
Implementation Method 2
a transfer member configured to transfer the toner image transferred on the intermediate transfer belt on a recording medium, a power supply configured to apply a transfer voltage to the transfer member
Data Source
AI summary
An image forming apparatus includes an image carrier, an image forming unit, an intermediate transfer belt, a power supply, a transfer member to transfer toner image on the intermediate transfer belt to a recording medium, and a sensor to detect, as density information, a density of the recording medium toner image. In an adjustment mode, (i) a test recording medium is output as a test chart by applying multiple levels of test voltages to the transfer member to transfer test toner images to the test recording medium, (ii) the transferred test toner images are detected via the sensor, and (iii) a transfer voltage is adjusted based on the sensor detection. In the adjustment mode, test toner image groups are set, one test toner image group is extracted based on an index value, and the transfer voltage is adjusted based on the density information of the extracted test toner image group.