Fixing Device Differential Pressure Control for Image Quality
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in maintaining consistent pressure distribution across the fixing nip, leading to uneven toner fixation and image quality issues, particularly due to higher peak pressures on the inlet side compared to the outlet side.
Innovation Solution
A fixing device with a pressurizing rotary body and a supporting part that ensures equal or lower peak pressure on the outlet side compared to the inlet side, achieved through a specific configuration of the pressurizing roll and pad member, allowing for controlled pressure distribution and improved toner fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fixing devices are used with standard pressure distribution, then the structure is simple, but the toner fixation uniformity deteriorates due to higher peak pressures on inlet side causing image deviation and contrast differences
Solution Approach 1:
The pad member is designed with different thicknesses at different locations (thinner at inlet side, thicker at outlet side) to create local variations in pressure distribution. This local quality adjustment ensures that the peak pressure on the outlet side is equal to or lower than the peak pressure on the inlet side, improving toner fixation uniformity without requiring complex overall structural changes
Solution Approach 2:
Instead of applying uniform pressure or higher pressure at the inlet side as in conventional designs, the invention inverts the approach by designing the pad member to provide relatively higher pressure support at the outlet side through its thickness variation, thereby equalizing or reducing the peak pressure difference and preventing image deviation
2Strength
If higher peak pressure is applied on inlet side, then toner fixation force is improved, but image quality deteriorates due to toner slipping and contrast differences
Solution Approach 1:
The invention changes the pressure distribution parameter along the transporting direction by varying the pad member thickness. This parameter change ensures that while sufficient fixation force is maintained, the peak pressure on the outlet side is controlled to be equal to or lower than on the inlet side, preventing toner slipping and maintaining image quality uniformity
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 enhances the uniformity of toner fixation, reduces image deviation, and minimizes contrast differences between the toner and the recording paper, resulting in improved image quality by maintaining a lower pressure on the outlet side, thus preventing toner slipping and maintaining image integrity.
Implementation Method 1
a fixing rotary body that heats toner while rotating and fixes the toner on a recording medium
Implementation Method 2
a pressurizing rotary body that sandwiches and pressurizes the toner and the recording medium by the fixing rotary body
Data Source
AI summary
A fixing device includes a fixing rotary body that heats toner while rotating and fixes the toner on a recording medium, a pressurizing rotary body that sandwiches and pressurizes the toner and the recording medium by the fixing rotary body, and a supporting part that supports the fixing rotary body from the inside so that a peak pressure on an outlet side of the recording medium becomes equal to or lower than a peak pressure on an inlet side, in a contact part where the fixing rotary body and the pressurizing rotary body come into contact with each other.