Fixing Device Eccentric Cam Overrun Noise Reduction
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses cannot effectively restrain the overrun of the eccentric cam, leading to impulsive sounds during the changing operation of nip pressure between the heating and pressuring rollers.
Innovation Solution
The fixing device incorporates an eccentric cam with a gear train and a driving part that includes depressions on its outer circumference face to prevent overrun by braking the cam during posture changes, using a tensile spring to adjust nip pressure between a first and second pressure setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the eccentric cam is used to change nip pressure between heating and pressuring rollers, then the nip pressure can be adjusted between first and second pressure settings, but impulsive sounds occur due to overrun of the eccentric cam during pressure changes
Solution Approach 1:
A buffer member is introduced as an intermediary element between the driving member and the eccentric cam. This buffer member absorbs the overrun of the eccentric cam through elastic deformation, preventing direct transmission of impulsive sounds to the heating and pressuring rollers. The buffer member acts as a mediator that converts harmful mechanical impact into manageable elastic energy.
Solution Approach 2:
The buffer member is pre-positioned between the driving member and eccentric cam to provide cushioning before the overrun occurs. During normal operation, the buffer member maintains a predetermined play that allows it to absorb upcoming impacts. This beforehand cushioning prevents impulsive sounds by preparing the elastic element in advance to absorb the eccentric cam's overrun.
2Ease of operation
If the following member is allowed to overrun with predetermined play, then the pressure contact state can be released, but the overrun cannot be restrained leading to instability
Solution Approach 1:
The buffer member serves as a mediator between the driving member and the eccentric cam, allowing the eccentric cam to overrun for pressure release while preventing excessive movement. The buffer member's elastic properties enable it to accommodate the necessary play for pressure release while maintaining overall system stability through its restraining effect.
Solution Approach 2:
The buffer member changes its physical state from a rigid constraint to an elastic element that can dynamically adjust its stiffness. During overrun, the buffer member deforms elastically to allow pressure release, then returns to its original state to restrain further movement. This parameter change enables both pressure release functionality and stability maintenance.
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 solution effectively reduces impulsive sounds and prevents overrun of the eccentric cam, enhancing the operational stability and reducing noise during nip pressure changes in the fixing device.
Implementation Method 1
The tensile spring is connected between the first supporting body and the second supporting body at its both ends to pull the first supporting body to a side of the second supporting body
Implementation Method 2
The eccentric cam is rotatably supported at a position between the first supporting body and the second supporting body in the lateral plate, makes its outer circumference face come into contact with the roller, and is rotated to change a posture of the second supporting body
Implementation Method 3
The heating body is rotated and heats a medium on which a toner image is formed
Implementation Method 4
The pressuring body forms a nip with the heating roller, is rotated and pressures the medium passing through the nip
Data Source
AI summary
A fixing device includes a heating body, a pressuring body, a lateral plate supporting the heating body or the pressuring body, a first supporting body supporting the heating or pressuring body, a second supporting body including a roller, a tensile spring connected between the first and second supporting bodies, an eccentric cam and a driving part. The first and the second supporting body are swingable to the lateral plate. The eccentric cam is supported between the first and second supporting bodies in the lateral plate, and is rotated while contacting with the roller to change the second supporting body, thereby changing a nip pressure of the first and second supporting bodies to a first pressure or a second pressure lower than the first pressure. In the eccentric cam, between first and second portions making the first and second pressures, at least one depression receiving insertion of the roller is formed.