Fixing Device Heater Shape Stability via Grooved Fixed Member
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges with deformation of pipe-shaped heating members, leading to increased component complexity and limited design flexibility, while also requiring longer warm-up and first print times.
Innovation Solution
A fixing device with a flexible endless belt, a rotating member, and a fixed member forming a nip, where the heater has bent portions and a reinforcing member to prevent deformation, along with a low-friction sheet and lubricant to reduce wear and improve heating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stay bolts are used as a holder to hold and maintain the shape of the pipe-shaped heater, then the heater deformation is prevented, but the number of component parts increases and assembly becomes complicated
Solution Approach 1:
The patent combines the holder function with the existing fixed member (pressing member) by forming an insertion groove directly on the fixed member. This integration eliminates the need for separate stay bolts, reducing component count while maintaining the heater shape stabilization function. The fixed member now serves dual purposes: pressing the heater belt assembly and holding the heater shape through the insertion groove.
Solution Approach 2:
The fixed member is designed to perform multiple functions: it acts as a pressing member to apply pressure to the heater and belt assembly, and simultaneously serves as a holder for the pipe-shaped heater through the insertion groove. This multi-functionality reduces the need for separate components while maintaining both pressing and shape-holding capabilities.
2Productivity
If the pipe-shaped heater is made thinner to improve heating efficiency, then warm-up time is reduced, but the heater becomes more prone to deformation
Solution Approach 1:
The patent applies preliminary anti-action by designing the insertion groove in advance to counteract the spring-back tendency of the thin-walled pipe-shaped heater. The groove geometry is specifically designed to compensate for the expected deformation, holding the heater in the correct shape during operation despite its thin walls that prioritize heating efficiency.
3Loss of time
If the heater is heated more intensely to minimize warm-up time, then first printing speed improves, but the risk of heater deformation increases
Solution Approach 1:
The insertion groove acts as a preemptive structural support that cushions against thermal deformation before it occurs. By providing this mechanical constraint in advance, the heater can be heated intensely to minimize warm-up time without risking shape accuracy, as the groove prevents deformation during the heating process.
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 minimizes warm-up time, first print time, and reduces defective fixing, while simplifying assembly and reducing deformation issues, thus enhancing the performance and reliability of the image forming apparatus.
Implementation Method 1
the pipe-shaped heater itself is heated by a heat source to heat the entire endless fixing belt
Implementation Method 2
a pipe-shaped heating member made of heat conductive metal disposed opposite an inner circumferential surface of an endless fixing belt
Implementation Method 3
to hold and maintain a shape of the pipe-shaped heater near the opening to prevent the opening from expanding near the nip due to the spring-back tendency of the metal
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A fixing device (20) comprises a flexible endless belt (21) rotated in a prescribed direction to heat and fuse a toner image (T), a rotating member (31) that presses against and rotates the flexible endless belt (21), and a fixed member (26) disposed on an inner circumferential surface side of the flexible endless belt (21) to press against the rotating member (31) via the flexible endless belt (21). A heater (22) is fixedly disposed facing an inner circumferential surface of the flexible endless belt (21) to heat the flexible endless belt (21). The heater (22) includes an opening (22a) opposed to the rotating member (31) that accommodates the fixed member (26). A reinforcing member (23) is fixedly disposed on an inner circumferential surface side of the heater (22) to contact and reinforce the fixed member (26).