Fixing Device Belt Cooling for Gloss Uniformity
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Solution Overview
Problem
Existing fixing devices in image forming devices, such as printers and copiers, generate gloss differences in toner images due to temperature variations in the fixing belt, which are exacerbated by pre-heating methods that increase the device's internal temperature, potentially hardening toner and affecting image formation.
Innovation Solution
A fixing device with an endless belt and a cooler that cools the paper-contact range of the belt before thermal fixing, reducing temperature differences and heat absorption, thereby minimizing gloss differences without increasing the device's temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the recording sheet is pre-heated by the heater before thermal fixing, then the gloss difference is reduced, but the temperature inside the image forming device increases and the developing unit is heated causing toner to become hard
Solution Approach 1:
The patent applies local quality by cooling only the specific region of the fixing belt that contacts the recording sheet (the paper-contact range) rather than cooling the entire belt or pre-heating the recording sheet. The cooler is positioned to cool only the necessary area, maintaining uniform temperature distribution locally without affecting the overall device temperature or the developing unit.
Solution Approach 2:
Instead of pre-heating the recording sheet before thermal fixing (the conventional approach), the patent inverts the approach by cooling the fixing belt before the recording sheet contacts it. This reversal eliminates the need to heat the recording sheet while still achieving uniform temperature conditions for consistent gloss quality.
2Stability of the object's composition
If the recording sheet is pre-heated by the heater, then the difference in temperature between the recording sheet and fixing belt is reduced, but this increases energy consumption and affects toner properties in the developing unit
Solution Approach 1:
The cooler is positioned to cool only the paper-contact range of the fixing belt, applying temperature control locally where needed rather than heating the entire recording sheet. This localized approach achieves temperature stability with minimal energy consumption and avoids affecting other components.
Solution Approach 2:
The patent changes the temperature parameter of the fixing belt locally by cooling it before contact with the recording sheet, rather than heating the recording sheet. This parameter change in the fixing belt achieves the same temperature uniformity effect while avoiding the energy consumption and side effects of pre-heating the recording sheet.
3Device complexity
If the fixing belt temperature is allowed to vary, then the structure is simpler, but gloss difference occurs between different recording sheets and parts of the same sheet
Solution Approach 1:
The patent introduces a cooler positioned at a specific location to cool only the paper-contact range of the fixing belt. This localized temperature control maintains uniform temperature distribution in the critical area, ensuring consistent gloss quality without requiring complex temperature control throughout the entire belt or device.
Solution Approach 2:
The cooler cools the fixing belt in advance before the recording sheet contacts it, performing preliminary temperature equalization. This preliminary action prevents temperature variations from occurring in the first place, maintaining simple overall structure while achieving uniform gloss quality.
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 reduces gloss differences in toner images by equalizing belt temperatures, preventing excessive cooling and heat absorption, and maintaining a stable internal device temperature, thus optimizing image quality and reducing toner hardness issues.
Implementation Method 1
a cooler that cools at least a paper-contact range of the belt within which the recording sheet passing through the fixing nip is to contact
Data Source
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AI summary
A fixing device including: an endless belt that is driven to perform a circulating motion; a pressing member and a fixing roller that face each other with the endless belt therebetween, the pressing member being caused to press the fixing roller, which is preliminarily heated, via the belt to form a fixing nip in which a toner image is thermally fixed onto a recording sheet S passing through therein; a cooler that cools at least a paper-contact range of the belt within which the recording sheet S passing through the fixing nip contacts; and a temperature-decrease controller that causes the cooler to cool at least the paper-contact range of the belt before the toner image is thermally fixed onto the recording sheet S.