Fuser Frame Openings for Compact Insulated Pressing Roller Layout
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Solution Overview
Problem
Existing fixing devices face challenges in achieving compactness, high speed, and low cost while maintaining safety standards due to the need for increased insulation distances between the pressing roller and the device frame, leading to higher costs when using insulating resin or sheet members.
Innovation Solution
The fixing device incorporates a rotatable, cylindrical heating unit with a flexible film and a pressing roller, where the device frame includes openings longer than the rubber layer in the rotational axis direction to maintain insulation distances, allowing for downsizing and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the pressing roller and the device frame is narrowed to achieve compactness and downsizing, then the device size is reduced, but the insulation distance required by safety standards is not met
Solution Approach 1:
The patent applies dimensional change by providing openings in the device frame in the rotational axis direction (longitudinal direction) of the pressing roller. This allows the insulation distance to be secured in the width direction while maintaining a compact overall device size. The openings create spatial separation between the pressing roller and the frame in a dimension that does not increase the device's external dimensions.
Solution Approach 2:
The device frame is segmented by providing openings that divide the frame structure. These openings are strategically positioned to create insulation distance between the pressing roller and the frame without requiring additional insulating materials. The frame is divided into regions that provide electrical insulation through spatial separation.
2Reliability
If insulating resin members or sheet members are provided to secure the insulation distance between the pressing roller and the device frame, then the safety standard is met, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the insulating function from separate insulating materials (resin members or sheet members) and integrates it directly into the device frame structure through openings. This eliminates the need for additional insulating components, reducing part count and manufacturing cost while maintaining the required insulation distance.
Solution Approach 2:
The insulating function is merged with the device frame structure itself. The openings in the frame serve dual purposes: providing structural support and ensuring electrical insulation. This integration eliminates the need for separate insulating components and reduces overall manufacturing complexity and cost.
3Productivity
If the diameter of the pressing roller is increased to achieve higher fixing speed, then the productivity is improved, but the device size increases
Solution Approach 1:
The patent allows for a larger pressing roller diameter (for higher fixing speed) by using openings in the device frame to maintain insulation distance. This enables the pressing roller to be larger without proportionally increasing the overall device size, as the insulation is achieved through strategic openings rather than uniform spacing in all dimensions.
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 enables an inexpensive and space-saving fixing device that meets safety standards by securing the necessary insulation distances without increasing costs, facilitating compactness and higher speeds.
Implementation Method 1
the heater is heated by flowing AC current through the heat generating member formed on the substrate of the heater
Implementation Method 2
a rubber layer covering the core metal and configured to contact an outer peripheral surface of the rotatable member
Data Source
AI summary
A fixing device includes a rotatable member, a heating member in contact with an inner peripheral surface of the rotatable member; a pressing member and a metallic frame. The pressing roller includes a core metal and a rubber layer covering the core metal and forms a nip with the rotatable member. The metallic frame holds the pressing member and includes inlet and outlet portions provided with openings through which the recording material is conveyed to the nip and the recording material is conveyed from the nip to an outside. In a region other than the inlet and outlet portions, the frame is provided with an opening portion of which a length in a rotational axis direction of the pressing roller is longer than a length of the rubber layer in the rotational axis direction.