Cam Spring Mechanism for Noise Suppression in Fixing Apparatus
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Solution Overview
Problem
Conventional image forming devices experience abnormal noise due to sudden changes in the rotational posture of the cam, causing collision noise between components as the pressure roller transitions between contact and separation positions.
Innovation Solution
An image forming apparatus with a cam member, spring member, and regulating member that controls the rotation of the cam to manage the transition between pressure contact and separation positions, using a transmission section and drive source to regulate the movement and reduce sudden changes in the gap between components, thereby minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cam is rotated to displace the pressure roller between contact and separation positions, then the fixing device can perform thermal fixing and sheet separation functions, but abnormal collision noise is generated between components due to sudden changes in rotational posture
Solution Approach 1:
A buffer member is provided between the cam and the pressure roller unit to absorb shocks and reduce collision noise when the pressure roller transitions between contact and separation positions. The buffer member compresses during the transition, cushioning the impact that would otherwise occur between the cam and the pressure roller unit components.
Solution Approach 2:
The buffer member acts as an intermediary element between the cam and the pressure roller unit. Instead of the cam directly acting on the pressure roller unit components, the buffer member mediates the force transmission, reducing the harmful collision noise while still enabling the displacement function.
2Ease of manufacture
If a gap is formed between transmission components (shaft hole and shaft part), then assembly and disassembly are facilitated, but the gap causes collision noise when suddenly eliminated during cam rotation
Solution Approach 1:
The buffer member serves as an intermediary that prevents the sudden elimination of the gap between the shaft hole and shaft part from causing collision noise. By absorbing the shock during transitions, it allows the gap to exist for ease of assembly while preventing the harmful noise during operation.
Solution Approach 2:
The buffer member is positioned to cushion the impact before the gap between transmission components is fully eliminated, preventing the collision noise from occurring while still allowing the gap to exist for assembly purposes.
3Ease of operation
If the cam surface allows the pressure roller unit to be displaced in the urging direction, then the pressure roller can be separated from the fixing roller, but the rotational posture change causes abrupt direction change and collision noise
Solution Approach 1:
The buffer member compresses beforehand during the transition period when the cam surface is displacing the pressure roller unit, cushioning the abrupt direction change and preventing collision noise while still enabling the separation function.
Solution Approach 2:
The buffer member mediates between the cam surface displacement action and the pressure roller unit movement, smoothing out the abrupt direction changes that occur during rotational posture changes while maintaining the separation capability.
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 solution effectively suppresses abnormal noise generation by managing the rotational posture of the cam and reducing sudden changes in the gap between components, enhancing the operational quietness and durability of the image forming apparatus.
Implementation Method 1
The spring member has one end portion and another end portion. The one end portion is movable in interlocking relation with the cam member. The spring member is configured: to store a restoring force by the rotation of the cam member in the first direction and to suppress rotation of the cam member in the first direction; and to release the restoring force by the rotation of the cam member in the second direction and to facilitate rotation of the cam member in the second direction.
Data Source
AI summary
An image forming apparatus includes: a first fixing member; a second fixing member; a holding member; a cam member; an urging member; a spring member; a drive source; a transmission section; a regulating member; and a controller. The cam member is rotatable about an axis in a first direction and a second direction opposite to the first direction. The spring member has one end portion movable in interlocking relation with the cam member and another end portion whose movement is regulated by the regulating member. The spring member suppresses rotation of the cam member in the first direction while storing a restoring force by the rotation of the cam member in the first direction; and facilitates rotation of the cam member in the second direction while releasing the restoring force by the rotation of the cam member in the second direction.