Fixing Device Retaining Member UFP Reduction
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Solution Overview
Problem
The existing fixing devices in electrophotographic image forming apparatuses generate ultra-fine particles (UFPs) from toner wax during thermal fixing processing, which can lead to increased air pollution due to the wax liquefying and gasifying on the heating rotary member, resulting in particles floating in the air.
Innovation Solution
A fixing device is designed with a retaining member that covers the periphery of the heating rotary member to slow down air currents and increase the retention time of UFPs, facilitating their flocculation and adsorption, using a specific configuration of the retaining member's height and air flow management to minimize UFP release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal fixing processing is performed using a heating rotary member, then toner images are fixed with heat, but wax liquefies and gasifies to generate ultra-fine particles that float in the air
Solution Approach 1:
A retaining member is introduced as an intermediary component between the heating rotary member and the surrounding air. This retaining member captures and holds the ultra-fine particles generated during thermal fixing, preventing them from dispersing into the air while allowing the fixing process to continue effectively.
Solution Approach 2:
The retaining member creates a contained environment around the heating rotary member where ultra-fine particles are trapped. By controlling the local environment and preventing particle escape, the system effectively isolates the harmful particles from the surrounding air space.
2Object-generated harmful factors
If a retaining member is added to capture ultra-fine particles, then particle release is reduced, but device complexity increases
Solution Approach 1:
The retaining member is designed as a thin-walled cylindrical structure that provides effective particle containment without adding significant structural complexity. The simple cylindrical geometry with minimal material usage achieves the containment function while maintaining device simplicity.
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 configuration significantly reduces the number of UFPs released into the air by enhancing flocculation and adsorption, achieving a decrease rate of up to 50% compared to devices without the retaining member, while maintaining stability across varying conditions.
Implementation Method 1
a retaining member that covers the periphery of the heating rotary member to slow down air currents and increase the retention time of UFPs
Implementation Method 2
facilitating their flocculation and adsorption
Implementation Method 3
a fixing device provided in an electrophotographic image forming apparatus such as a copying machine or a laser beam printer that performs thermal fixing processing of a toner image with heat from a heating rotary member
Implementation Method 4
the wax liquefies and partially remains on the heating rotary member, and gasifies by receiving heat continuously. The gasified wax becomes ultra-fine particles (UFPs)
Data Source
AI summary
The fixing device includes a rotary member for contacting the unfixed toner image, a pressure member for forming the nip portion by contacting the rotary member, and a cover for covering the rotary member with a space between the rotary member and the cover, wherein in a cross section of the fixing device, the cross section being orthogonal to a generatrix direction of the rotary member, wherein a shortest distance(H) between the nip portion and a farthest surface portion of the rotary member farthest away from a surface portion forming the nip portion of the rotary member, a maximum width(W) of the rotary member in the conveyance direction of the recording member, and an area(S) of the space in a range of the maximum width W in the cross section satisfy with a relationship of S/W≥0.7×H.