Fixing Nip Cleaning via Segmented Temperature Control
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Solution Overview
Problem
Existing image forming apparatuses face challenges in simultaneously removing toner contaminants from both the rotatable fixing member and the pressing member surfaces, leading to image contamination and equipment damage due to the accumulation of paper powder and filler, which reduces the parting property and causes defects.
Innovation Solution
An image forming apparatus is designed to execute a cleaning mode where a cleaning sheet passes through the fixing nip, performing multiple cleaning operations in a single pass, with the first operation targeting toner contaminants on the fixing film and the second operation addressing paper powder and filler contaminants on the pressing roller, utilizing specific temperature control to enhance adhesive forces and removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cleaning sheet passes through the fixing nip to remove toner contaminants, then the toner contaminant removal efficiency is improved, but the paper powder and filler contaminants accumulate on the pressing member surface, reducing parting property
Solution Approach 1:
The cleaning process is divided into two distinct operations: first cleaning the fixing film surface, then cleaning the pressing member surface. This segmentation allows each cleaning operation to be optimized for its specific target, removing toner contaminants effectively while preventing paper powder accumulation on the pressing member.
Solution Approach 2:
The temperature of the pressing member is controlled to be at or above the softening point of toner during the cleaning process. This parameter change enables the toner to soften and transfer to the cleaning sheet, while the lower temperature prevents excessive melting that would cause paper powder adhesion.
2Strength
If the surface temperature of the pressing member is increased to melt toner for cleaning, then the adhesive force between toner and cleaning paper is improved, but the parting property of the pressing member is reduced
Solution Approach 1:
The pressing member temperature is periodically adjusted: raised to the softening point or higher during cleaning operations to enable toner transfer, then reduced to normal operating temperature for image fixing. This periodic temperature variation allows the pressing member to fulfill both cleaning and parting functions at different times.
Solution Approach 2:
The cleaning sheet serves dual purposes: it removes toner contaminants from the fixing film and simultaneously cleans the pressing member surface. The pressing member's own heat, when elevated to the softening point, facilitates this self-cleaning process without requiring additional heating mechanisms.
3Manufacturing precision
If cleaning operations are performed repeatedly to remove toner contaminants, then the cleanliness of the fixing members is improved, but the cleaning time and complexity increase
Solution Approach 1:
Two cleaning operations (cleaning the fixing film and cleaning the pressing member) are merged into a single cleaning sheet pass through the fixing nip. This combination achieves comprehensive cleaning of both surfaces simultaneously, reducing the total cleaning time and operational complexity.
Solution Approach 2:
The cleaning sheet performs multiple functions in sequence: it first picks up toner contaminants from the fixing film surface, then transfers and removes toner contaminants from the pressing member surface. This multi-functionality allows a single cleaning operation to address contamination on both critical surfaces.
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 approach effectively removes 95% or more of toner contaminants from both surfaces, preventing image contamination and maintaining equipment usability, while ensuring efficient cleaning without impairing the parting properties of the surfaces.
Implementation Method 1
a fixing device for fixing an unfixed toner image, which has been transferred onto a recording material such as transfer paper or an OHP sheet at an image forming portion, on the recording material
Implementation Method 2
the unfixed toner image is heated and melted while nip-conveying the recording material carrying the unfixed toner image
Implementation Method 3
a pressing member such as the pressing roller is contacted to a rotatable fixing member such as a heated fixing roller or a heated fixing film and the unfixed toner image is heated and melted while nip-conveying the recording material
Implementation Method 4
the surface temperature of the pressing member at rest is made not less than a softening point of the toner, so that the toner contained in the toner contaminant deposited on the peripheral surface of the pressing member is melted. As a result, an adhesive force (bonding strength) between the toner contaminant and a solid white recording material on which the toner image is not formed
Implementation Method 5
an adhesive force (bonding strength) between the toner contaminant and a solid white recording material on which the toner image is not formed (herein referred to as the cleaning paper) and a permeation of the toner contaminant into the cleaning paper are increased
Data Source
AI summary
An image forming apparatus includes an image forming portion for forming an unfixed toner image on a recording material; and a fixing portion for heat-fixing the unfixed toner image on the recording material while nip-conveying the recording material in a fixing nip, the fixing portion includes a first rotatable member contactable to the unfixed toner image, and a second rotatable member contacted to the first rotatable member to form the fixing nip between itself and the first rotatable member. The image forming apparatus is capable of setting a cleaning mode in which the fixing portion is cleaned by a cleaning sheet while nip-conveying the cleaning sheet in the fixing nip. When the cleaning mode is set, the image forming apparatus executes a plurality of types of cleaning operations in a period in which a single cleaning sheet passes through the fixing nip.