Fixing Device Heater Position Adjustment for Durability
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses face challenges in energy efficiency and heater durability due to the integral movement of the nip formation pad and heater, leading to increased load and potential breakage of the heater sealing portion during repeated press and release cycles.
Innovation Solution
The design incorporates a holder with a movable slot to support the heater relative to the nip formation pad, allowing for a larger distance between the heater and the pad during the nip formation position and a reduced distance during the release position, along with a contact-separation mechanism and a harness that applies a force to return the heater to a straight position, reducing the load on the heater and preventing contact with the stay and belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the heater and nip formation pad are fixed together on a holder to maintain constant clearance, then the structural simplicity is improved, but the load on the heater sealing portion increases and durability decreases
Solution Approach 1:
The holder is divided into a first holder supporting the nip formation pad and a second holder supporting the heater, allowing independent movement of each component. This segmentation enables the heater to be separated from the pad during release, reducing load on the sealing portion while maintaining structural organization through distinct functional zones.
Solution Approach 2:
The heater is made movable relative to the nip formation pad through the slot mechanism in the holder. During pressing operation, the heater can move closer to the pad, and during release, the heater moves away, creating a dynamic clearance that reduces stress on the sealing portion compared to a fixed rigid connection.
2Manufacturing precision
If the heater is disposed at a predetermined constant clearance with respect to the free belt and pad, then the manufacturing precision is improved, but the energy efficiency decreases due to unnecessary heating
Solution Approach 1:
The clearance between the heater and the nip formation pad is made dynamic rather than constant. The slot mechanism allows the heater to move closer to the pad during pressing operation, minimizing the clearance and reducing energy loss through radiation and convection, while still maintaining precise positioning control through the holder structure.
Solution Approach 2:
The heater position is periodically adjusted between pressing and release states. During pressing, the heater is positioned close to the pad for efficient energy transfer, and during release, the heater moves away, creating a periodic action that optimizes energy efficiency by minimizing unnecessary heating when not in use.
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 enhances energy efficiency by minimizing unnecessary energy consumption and extends the lifespan of the heater by reducing the load on the sealing portion, with the heater sealed portion remaining intact even after 240 thousand cycles compared to 120 thousand cycles in conventional designs.
Implementation Method 1
a heater enclosed in the loop formed by the endless belt to heat the endless belt
Implementation Method 2
a heater enclosed in the loop formed by the endless belt to heat the endless belt
Implementation Method 3
a pad that is disposed inside the loop formed by the endless belt and extends in a longitudinal direction of the elastic roller. The pad, which is also called a nip formation pad and which elastically deforms the elastic roller
Data Source
AI summary
A fixing device includes an endless belt, a pressure rotator that contacts the endless belt, a nip formation pad in the endless belt to form a fixing nip between the endless belt and the pressure rotator, a heater in the endless belt to heat the endless belt, a stay to support the nip formation pad, a contact-separation mechanism that presses the nip formation pad against the pressure rotator in a releasable manner, a holder movable between a nip formation position and a release position to support the stay, and an adjustment mechanism. The holder is provided with a slot to support the heater, and the adjustment mechanism makes a distance between the heater and the nip formation pad when the holder is at the nip formation position larger than a distance between the heater and the nip formation pad when the holder is at the release position.