Fixing Device Temperature Control for Paper Smoothness
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Solution Overview
Problem
Image forming apparatuses face the challenge of 'see-through' defects due to uneven toner melting on recording papers with varying surface smoothness, leading to darkness non-uniformity and potential issues like uneven glossiness, which existing solutions attempt to address through pressure distribution and temperature control but result in increased costs and complexity.
Innovation Solution
A fixing device with a rotatable pressing member and a controller that adjusts the temperature of the pressing member based on the recording paper's smoothness, forming a foundation structure to prevent excessive toner melting and maintain uniformity, using cooling fans to regulate the pressing roller's surface temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the temperature of the rotatable pressing member is lowered to suppress heat supply to the lowermost toner layer, then the foundation structure is formed to prevent see-through defects on low-smoothness paper, but the uppermost toner layer may not melt sufficiently on high-smoothness paper causing poor image quality
Solution Approach 1:
The pressing member temperature is made dynamically adjustable rather than fixed. The controller changes the temperature based on detected paper smoothness, allowing the system to adapt to different paper types and prevent both see-through defects and image quality degradation
Solution Approach 2:
The temperature parameter of the pressing member is changed according to paper smoothness characteristics. By detecting paper smoothness and adjusting the pressing member temperature accordingly, the system optimizes toner melting for each paper type, forming foundation structures on rough paper while maintaining sufficient melting on smooth paper
2Manufacturing precision
If the pressure distribution at the nip is switched depending on recording paper type, then the toner melting degree is controlled, but the pressure fluctuates and increases device size and cost
Solution Approach 1:
The patent extracts the temperature control function from the pressure control system. Instead of switching pressure distribution to control toner melting, the system maintains constant pressure and uses temperature adjustment of the pressing member to achieve the same effect, simplifying the overall control system
Solution Approach 2:
The mechanical pressure distribution switching system is replaced with a thermal control system. The controller adjusts the pressing member temperature to control toner melting degree, substituting mechanical complexity with thermal regulation that achieves the same manufacturing precision goal
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 prevents 'see-through' defects on low-smoothness papers while maintaining image quality on high-smoothness papers, reducing the risk of uneven glossiness and operational costs by dynamically controlling the pressing roller's temperature in response to paper smoothness.
Implementation Method 1
the heat supply from the rotatable pressing member side to the toner layer located in the lowermost layer side on the recording paper
Implementation Method 2
using cooling fans to regulate the pressing roller's surface temperature
Data Source
AI summary
A fixing device includes: a rotatable fixing member configured to fix at a nip a toner image formed on recording paper; a rotatable pressing member configured to form the nip between itself and the rotatable fixing member; and a controller configured to control a temperature of the rotatable pressing member depending on smoothness of the recording paper.