Fuser Pad Varying Thickness Prevents Curling
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Solution Overview
Problem
Belt-based fixing devices in image forming apparatuses face issues with curling and winding of moist recording sheets around the fuser belt, leading to malfunction or failure, particularly due to the low heat capacity of the fuser belt and the subsequent curling behavior similar to a bimetallic strip.
Innovation Solution
A fixing device with a rotatable, flexible fuser belt and a pressure member, featuring a fuser pad with distinct sections for optimal heat and pressure distribution, including an upstream planar surface, a midstream concave surface, and a downstream protruding surface, along with a pressure member having a concave roller with tapered diameter, to prevent curling and ensure proper sheet separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a belt-based fixing device is used, then heating efficiency is improved and heat capacity is reduced, but curling and winding of recording sheets occur leading to malfunction
Solution Approach 1:
The fuser pad is designed with non-uniform thickness, being thinner at the upstream section and thicker at the downstream section. This local variation in thickness compensates for the curling tendency of recording sheets by providing differential support and pressure distribution along the fixing path, thereby preventing winding while maintaining the low heat capacity advantage of the belt-based system
Solution Approach 2:
The fuser pad acts as an intermediary element between the fuser belt and the recording sheet. It mediates the interaction by providing mechanical support and controlled pressure distribution, preventing direct contact between the curling sheet and the belt while still enabling effective heat transfer for fixing
2Ease of manufacture
If the fuser pad has uniform thickness, then manufacturing is simplified, but heat and pressure distribution becomes non-uniform leading to poor fixing quality
Solution Approach 1:
The fuser pad intentionally incorporates local quality variations through its non-uniform thickness profile. The upstream section is thinner while the downstream section is thicker, creating localized differences in heat capacity and pressure distribution that compensate for the natural curling behavior of recording sheets and ensure uniform fixing quality across the entire sheet surface
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 curling and winding of the recording sheet, ensuring stable and efficient fixing processes by maintaining uniform heat and pressure distribution across the fixing nip, enhancing the reliability of the image forming apparatus.
Implementation Method 1
A heater 125 is disposed inside the tubular pipe 122 to radiate heat to the pipe 122
Implementation Method 2
which in turn conducts heat to the fuser belt 121 entrained around the pipe 122
Implementation Method 3
the fuser roller heats the incoming sheet to fuse and melt the toner particles, while the pressure roller presses the sheet against the fuser roller to cause the molten toner to set onto the sheet surface
Data Source
AI summary
A fixing device includes a rotatable, flexible fuser belt, a fuser pad, and a pressure member. The rotatable, flexible fuser belt is looped into a generally cylindrical configuration. The fuser pad extends in an axial, longitudinal direction thereof inside the loop of the fuser belt. The pressure member extends in the axial direction opposite the fuser pad with the fuser belt interposed between the fuser pad and the pressure member. The pressure member presses against the fuser pad through the fuser belt in a load direction to form a fixing nip therebetween, through which a recording medium is conveyed in a conveyance direction. The fuser pad includes an upstream section, a midstream section, and a downstream section having differing thicknesses is a load direction arranged in series from upstream to downstream in the conveyance direction.