Fixing Roller Pressure Profile for Toner Adhesion Control
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Solution Overview
Problem
Existing external heating type fixing devices in image forming apparatuses face issues with toner and paper dust adhering to the fixing roller and heating member, leading to image defects due to the formation of a sticking substance with different characteristics, which is not effectively addressed by previous configurations.
Innovation Solution
A fixing device with a fixing roller having a rubber layer and a rotating member that forms a contact portion with a pressure distribution including a region where pressure is increased after being decreased downstream of the center in the rotational direction, preventing the sticking substance from adhering to the heating member by applying a shearing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating member has high adhesion to toner to prevent toner scattering, then toner release properties improve, but paper dust and toner mix to form sticking substance that accumulates on the heating member
Solution Approach 1:
The invention applies different pressure conditions to different regions of the heating member. Specifically, the pressure between the fixing roller and heating member is controlled to have a pressure decreased region on the downstream side, creating localized quality differences that prevent sticking substance accumulation while maintaining necessary adhesion in other regions
Solution Approach 2:
The invention changes the pressure parameter along the rotational direction of the heating member. By creating a pressure decreased region downstream of the center, the pressure distribution is optimized to reduce sticking substance adhesion while maintaining effective toner fixing in the high-pressure region
2Use of energy by moving object
If pressure is uniformly distributed across the contact portion, then heating efficiency is maintained, but sticking substance accumulates on the heating member surface
Solution Approach 1:
The contact portion is divided into different pressure regions: a high-pressure region for effective heating and toner fixing, and a low-pressure region on the downstream side that prevents sticking substance accumulation. This local quality differentiation resolves the contradiction between heating efficiency and sticking prevention
Solution Approach 2:
The invention converts the potentially harmful effect of pressure (which could cause sticking substance accumulation) into a beneficial effect by strategically creating a pressure decreased region. This transforms the pressure distribution from a uniform state that causes accumulation into a differentiated state that prevents accumulation while maintaining heating efficiency
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 the sticking substance from adhering to the heating member, preventing image defects and ensuring consistent image quality even after printing a large number of sheets.
Implementation Method 1
heat of the rotating member transfers to the fixing roller from the rotating member via the contact portion
Implementation Method 2
the contact portion includes a region where pressure is increased after being decreased on a downstream side further than a center of the contact portion in the rotational direction of the rotating member
Data Source
AI summary
A fixing device configured to fix a toner image on a recording material by heating while conveying the recording material that bears the toner image by a nip portion, the fixing device includes a fixing roller having a rubber layer, a rotating member configured to form a contact portion between the rotating member and the fixing roller, and a pressure member configured to form the nip portion cooperatively with the fixing roller. In the fixing device, heat of the rotating member transfers to the fixing roller from the rotating member via the contact portion, and the contact portion includes a region where the pressure is increased after being decreased on a downstream side further than a center of the contact portion in the rotational direction of the rotating member.