Fixing Device Nip Pad Asymmetric Stay Positioning
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Solution Overview
Problem
The existing image forming apparatuses face challenges in maintaining stable pressure distribution and efficient toner fixation due to the instability in the nip formed by the heat roller and the belt, leading to inconsistent toner image fixation and potential misalignment of pads.
Innovation Solution
The design includes a fixing device with a heat roller, a belt, and pads where the second pad is located upstream of the first pad in the conveyance direction, and the stay's contact area is positioned downstream of the nip's center and upstream of the first pad, allowing for efficient urging forces to be applied, preventing pad separation and ensuring a stable pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the stay's contact area with the holder is positioned at the center of the nip, then the structure is simple, but the pressure distribution becomes unstable and pads may separate
Solution Approach 1:
The stay's contact area with the holder is deliberately positioned asymmetrically relative to the nip center, specifically downstream of the nip center and upstream of the first pad. This asymmetric positioning creates a lever arm that generates a stabilizing moment to counteract forces that would cause pad separation, thereby achieving stable pressure distribution without requiring complex additional components.
2Reliability
If the second pad is positioned downstream of the first pad, then the structure is conventional, but the pressure distribution becomes unstable leading to inconsistent toner fixation
Solution Approach 1:
The patent inverts the conventional pad arrangement by positioning the second pad upstream of the first pad in the conveyance direction, rather than downstream. This inversion, combined with the specific positioning of the stay's contact area, creates a stable pressure distribution that ensures consistent toner fixation across the entire nip region.
3Stability of the object's composition
If the stay contact area is positioned upstream of the nip center, then pad separation is prevented, but the positioning accuracy of pads decreases
Solution Approach 1:
The stay's contact area with the holder is positioned in a specific local region that is downstream of the nip center and upstream of the first pad. This localized positioning creates an optimal balance point that simultaneously provides stabilizing moment to prevent pad separation and maintains adequate positioning accuracy for consistent toner fixation.
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 enables a stable and consistent pressure distribution across the nip, ensuring effective toner fixation and improved positioning accuracy of the pads, thereby enhancing the image forming process.
Implementation Method 1
The urging member urges the stay toward the rotator in an urging direction
Implementation Method 2
The heater is positioned within the roller... heating and melting toner on the sheet
Implementation Method 3
The first pad is configured to press the belt toward the rotator... The second pad is configured to press the belt toward the rotator
Data Source
AI summary
A device includes a rotator, a belt facing the rotator and having an outer peripheral surface which contacts the rotator to form a nip therebetween, a first pad configured to press the belt toward the rotator to form one part of the nip, a second pad configured to press the belt toward the rotator, to form another part of the nip, a holder holding the first pad and the second pad, a stay supporting the holder, and an urging member urging the stay toward the rotator in an urging direction. The second pad is located upstream of the first pad in a conveyance direction in the nip orthogonal to the urging direction. At least a portion of a contact area between the stay and the holder is located downstream of a center of the nip and upstream of a front edge of the first pad in the conveyance direction.