Fixing Device Pressure Pad Curvature Uniform Nip
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Solution Overview
Problem
Existing fixing devices in electrophotographic image forming apparatuses face challenges in suppressing image fixing unevenness and achieving energy savings, as they struggle to uniformly apply pressure due to deflection of pressure rollers and reinforcing members, leading to increased heat capacity and reduced energy efficiency.
Innovation Solution
A fixing device design featuring a pressure pad with a curved second main surface and a sandwiching member with a flat abutting part, which absorbs deflection and maintains uniform pressure distribution across the width of the nip, while minimizing the thickness and heat capacity of the reinforcing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a plate-like reinforcing member is provided to suppress deflection of the fixing member, then deflection suppression is improved, but heat capacity increases and energy saving goal cannot be achieved
Solution Approach 1:
The sandwiching member has a non-uniform thickness distribution where the thickness increases from the pressure roller contact side toward the sandwiching member side. This local variation in thickness provides enhanced deflection suppression capability at the critical pressure application region while maintaining thinner sections elsewhere to minimize overall heat capacity and energy consumption.
Solution Approach 2:
Instead of uniformly increasing the thickness of the sandwiching member in all directions, the invention introduces a dimensional variation along the width direction of the fixing device. The thickness is designed to change gradually from one side to the other, creating a three-dimensional profile that optimizes both structural support and thermal properties.
2Stability of the object's composition
If the thickness of the reinforcing member is increased to completely eliminate deflection, then deflection suppression is improved, but heat capacity increases
Solution Approach 1:
The sandwiching member implements localized thickness enhancement rather than uniform thickening. The thickness is specifically increased in the region where the pressure roller contacts the pressure pad, providing targeted deflection suppression exactly where needed while keeping other regions thinner to minimize heat capacity.
Solution Approach 2:
The invention applies partial action by providing thickness enhancement only in the critical region where deflection occurs, rather than excessively increasing the thickness throughout the entire sandwiching member. This partial thickening is sufficient to eliminate deflection at the contact point while avoiding unnecessary heat capacity increase in non-critical areas.
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 design ensures uniform pressure application across the image width, preventing fixing unevenness and achieving energy savings by reducing the heat capacity of the fixing device, thereby improving image quality and energy efficiency.
Implementation Method 1
a pressure roller 10 and a pressure pad 22 arranged in a manner facing each other while interposing the conveyance path so as to form a nip N; and a sandwiching member 23 arranged on an opposite side of a side where the pressure roller 10 is located when viewed from the pressure pad 22, and used to sandwich the pressure pad 22 with the pressure roller 10 in a pressed state in which the pressure pad 22 is pressed by the pressure roller 10
Implementation Method 2
a heating source 25 that heats a toner image formed on a recording material
Implementation Method 3
a heating source 25 that heats a toner image formed on a recording material
Data Source
AI summary
A fixing device fixes a toner image onto a recording material by applying heat and pressure to the toner image formed on the recording material at a nip provided in a conveyance path of the recording material, and includes: a heating source; a pressure roller and a pressure pad; and a sandwiching member, wherein the pressure pad includes a first main surface and a second main surface, and the first main surface is formed of a long plate-like member, the sandwiching member includes a long plate-like abutting part, and a width-direction center in an area included in the second main surface and corresponding to a recording material passing region provided in the nip bulges toward the abutting part side more than width-direction both ends of the area included in the second main surface and corresponding to the recording material passing region provided in the nip.