Fixing Device With Gap-Offset Separation Claws for Uniform Toner Fixation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing fixing devices in electrophotographic image forming apparatuses experience uneven temperature distribution along the axial direction due to gaps in heating elements, leading to improper toner fixation on paper, and the use of separation members further decreases the surface temperature of the pressing roller, exacerbating the issue.
Innovation Solution
A fixing device with a cylindrical fixing belt, a pressing member, a heater with resistance heating elements arranged in gaps, and a separation member with claws positioned to avoid these gaps, ensuring uniform temperature distribution and proper toner fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heating elements are arranged with gaps in the axial direction, then the structure is simplified and manufacturing is easier, but the temperature distribution becomes uneven
Solution Approach 1:
The pressing roller surface is designed with different thermal properties in different regions. The separation member contact region has higher thermal conductivity or heat capacity to compensate for the gaps between heating elements, creating local quality variations that result in uniform overall temperature distribution.
Solution Approach 2:
The thermal parameters (conductivity, capacity) of the pressing roller are adjusted in the separation member contact region to compensate for the discontinuous heating. By changing material parameters or geometric parameters of the pressing roller, the temperature uniformity is achieved despite the gapped heating element arrangement.
2Ease of operation
If a separation member is added to prevent paper sticking, then paper separation is improved, but the surface temperature of the pressing roller decreases further
Solution Approach 1:
The pressing roller is designed with differentiated thermal characteristics: the separation member contact region has enhanced thermal properties to maintain temperature despite continuous contact with the separation member, while other regions have standard thermal properties. This local quality differentiation allows effective paper separation without compromising overall temperature uniformity.
Solution Approach 2:
The heat absorption effect of the separation member, which initially causes temperature reduction, is converted into a benefit by strategically positioning it in a region where it can effectively separate paper while the thermal design compensates for the heat loss. The separation member's contact function and thermal management work together to achieve both separation and temperature uniformity.
3Ease of operation
If the separation member contacts the pressing roller at gap positions, then paper separation is effective, but temperature uniformity deteriorates
Solution Approach 1:
The pressing roller is designed with non-uniform thermal distribution to compensate for the separation member's heat absorption at gap positions. The regions corresponding to heating element gaps have enhanced thermal properties, while other regions have standard properties, creating a compensated temperature profile that remains uniform overall.
Solution Approach 2:
The thermal design of the pressing roller is intentionally asymmetric or non-uniform to counterbalance the periodic heat absorption caused by the separation member's contact at gap positions. This asymmetric thermal compensation ensures that the overall temperature distribution remains uniform despite the periodic disturbances.
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 maintains uniform temperature across the axial direction, preventing excessive temperature rise and ensuring effective toner fixation on paper, even with varying paper sizes.
Implementation Method 1
The resistance heating elements are arranged on one surface of the base board, where faces an inner surface of the fixing belt, with gaps in the axial direction, and generates heat by being energized
Implementation Method 2
The heater extends in the axial direction of the fixing belt, comes into contact with an inner surface of the fixing belt facing the pressure region, and heats the fixing belt
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fixing device (7) includes a fixing belt (20), a pressing member (21), a heater (23), and a separation member (35). The separation member (35) comes into contact with a surface of the pressing member (21) and peels off the medium passed through the pressure region, from the surface of the pressing member (21). The heater (23) includes a base board (30), and a plurality of resistance heating elements (32A, 32B, 32C). The base board (30) is made of insulator and extends in the axial direction corresponding to the fixing belt (20). The resistance heating elements (32A, 32B, 32c) are arranged on one surface of the base board (30), where faces an inner surface of the fixing belt (20), with gaps in the axial direction, and generates heat by being energized. The separation member (35) has at least one separation claw (36) which is in contact with the surface of the pressing member (21) at a position displaced in the axial direction relative to the gaps.