Fixing Device Belt Temperature Uniformity via Guide Thermal Capacity
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Solution Overview
Problem
In image forming apparatuses, the fixing device's belt temperature is uneven due to divided heating portions and film guides, leading to local temperature decreases, which can result in fixing failures and increased warm-up times.
Innovation Solution
The fixing device employs a primary guide with a smaller thermal capacity opposite the heat generator's dividing region and a secondary guide with a larger thermal capacity opposite the non-dividing region, reducing heat conduction and minimizing local temperature decreases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the heat generator is divided into multiple heating portions, then the heating coverage is improved, but the temperature uniformity deteriorates due to heat loss at dividing regions
Solution Approach 1:
The patent applies local quality by giving different thermal capacities to different guides based on their positions. Guides at dividing regions (where heat loss occurs) are designed with smaller thermal capacities to prevent excessive heat absorption, while guides at non-dividing regions have larger thermal capacities. This localized differentiation compensates for the temperature non-uniformity caused by heat generator division, maintaining overall temperature uniformity across the belt width.
2Stability of the object's composition
If film guides are added to guide the belt, then the belt guidance is improved, but the temperature uniformity deteriorates due to heat conduction to guides
Solution Approach 1:
The patent implements local quality by varying the thermal capacity of guides according to their specific positions. Guides located at dividing regions of the heat generator are designed with smaller thermal capacities to minimize heat conduction and prevent local temperature decreases, while guides at non-dividing regions have larger thermal capacities. This position-dependent design allows the guides to perform their belt guidance function while compensating for their heat-sinking effect.
Solution Approach 2:
The patent applies parameter changes by modifying the thermal capacity parameter of the guides based on their positions. The thermal capacity is changed (reduced) for guides at dividing regions compared to guides at non-dividing regions. This parameter modification allows the system to balance the guidance function with temperature maintenance, preventing the guides from causing excessive heat loss at critical locations.
3Stability of the object's composition
If guides with large thermal capacity are used, then the belt guidance stability is improved, but the local temperature decrease worsens at dividing regions
Solution Approach 1:
The patent resolves this contradiction by applying local quality - different guides have different thermal capacities according to their positions. Guides at dividing regions have smaller thermal capacities to prevent local temperature decreases, while guides at non-dividing regions have larger thermal capacities for stable guidance. This spatial differentiation allows each guide to be optimized for its specific location's requirements.
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 maintains a consistent belt temperature, preventing fixing failures and reducing warm-up times while optimizing energy consumption.
Implementation Method 1
a heat generator 35 that heats the endless belt 20 to a predetermined temperature
Implementation Method 2
an amount of heat conducted from the endless belt to the primary guide disposed opposite the dividing region of the heat generator decreases
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A fixing device (9) includes a heater (22) including a heat generator (35) that is divided into a plurality of heat generating portions (31) in an axial direction of the endless belt (20). The heat generator (35) defines a dividing region (A) between adjacent ones of the plurality of heat generating portions (31) and a non-dividing region (B) other than the dividing region (A). A primary guide (26A) contacts and guides the endless belt (20). The primary guide (26A) is disposed opposite the dividing region (B) of the heat generator (35) and has a first thermal capacity. A secondary guide (26B) contacts and guides the endless belt (20). The secondary guide (26B) is disposed opposite the non-dividing region (B) of the heat generator (35) and has a second thermal capacity that is greater than the first thermal capacity.