Belt Fuser Pressure Pad with Hardness Gradient for Nip Control
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Solution Overview
Problem
Belt-type fusers face challenges in maintaining consistent nip pressure distribution due to changes in load applied to sheets, particularly with thin papers and envelopes, leading to uneven toner fixing and paper wrinkling, as they are more prone to deformation and require lighter loads, causing larger variations in nip pressure distribution compared to roller-type fusers.
Innovation Solution
A belt-type fuser design incorporating an endless fuser belt, a fuser rotator, a pressure pad, a holding member, a heater unit, and a pusher unit, where the pressure pad has a three-dimensional pressure face with specific profiles to compensate for deflections and maintain consistent nip pressure, ensuring proper fixation of toner images on various paper types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a belt-type fuser is used to reduce size and power consumption, then the device size and electricity saving are improved, but the nip pressure distribution becomes inconsistent leading to uneven toner fixing and paper wrinkling
Solution Approach 1:
The pressure pad is designed with varying hardness along its axial direction, with harder portions at the ends and softer portions in the middle. This local quality variation compensates for the larger deflections occurring at the ends of the belt-type fuser, thereby homogenizing the nip pressure distribution across the entire axial direction and preventing uneven toner fixing and paper wrinkling.
Solution Approach 2:
The invention changes the physical parameter of the pressure pad by creating a hardness gradient along its axial direction. This parameter change allows the pressure pad to adaptively compensate for load variations and deflections, maintaining consistent nip pressure distribution despite the inherent limitations of belt-type fuser structure.
2Object-affected harmful factors
If lighter load is applied to thin paper and envelopes to prevent deformation, then the paper quality is improved, but the nip pressure distribution varies more significantly
Solution Approach 1:
The pressure pad incorporates local quality variations in hardness to provide different levels of pressure support at different axial positions. This allows the system to maintain adequate nip pressure even when lighter loads are applied, preventing both paper deformation and excessive nip pressure variation.
Solution Approach 2:
The varying hardness structure of the pressure pad creates a dynamic response to different paper types and load conditions. The softer central portions accommodate thin paper with lighter loads while the harder end portions maintain sufficient pressure, enabling adaptive compensation without manual adjustment.
3Adaptability or versatility
If the holding member and pressure pad are made easier to deflect to accommodate paper types, then the adaptability is improved, but the nip pressure distribution variation increases
Solution Approach 1:
The pressure pad is designed with non-uniform hardness distribution, creating local quality differences that allow the holding member and pressure pad to deflect more easily in the central region while maintaining structural integrity and pressure stability at the ends. This resolves the contradiction between adaptability and pressure consistency.
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 design effectively maintains consistent nip pressure distribution along the axial direction, reducing the risk of uneven toner fixing and paper wrinkling, thereby enhancing image quality and operation reliability for belt-type fusers.
Implementation Method 1
the fusing member is heated
Implementation Method 2
Granulated toner attached on the surface of the sheet melts
Implementation Method 3
its outer peripheral surface is pressed by the outer peripheral surface of the pressing member to form a nip
Implementation Method 4
a sheet is subjected to heat and pressure
Implementation Method 5
a roller or a pressure pad or its holding member included in either of the fixing and pressing members is deflected in a direction normal to its axis
Data Source
AI summary
A fuser includes a pressure pad forming a nip with a fuser belt between the pad and a fuser rotator. A pressure face in contact with the belt has profiles in planes normal to the axis of the rotator. The profiles each include a reference section, the first to come into contact with the rotator with the belt in between when the pad forms the nip, and a boundary section at a threshold distance from the reference section in the width direction of the nip. When the pad is apart from the nip due to removal of a force applied by a pusher unit, the boundary section is, relative to the reference section, more largely displaced in the opposite direction to that of the rotator in one of the profiles located at a larger distance from a center portion of the pad in the axial direction of the rotator.