Fixing Device Heater Holder for Lubricant Leakage Control
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Solution Overview
Problem
The existing fixing devices in electrophotographic image forming apparatuses suffer from lubricant leakage at the end portion of the fixing film, leading to image defects due to the lubricant adhering to the recording material, despite efforts to reduce sliding friction and store lubricant in grooves.
Innovation Solution
A fixing device design featuring a lubricant holding portion and projected portion on the heater holder that regulates the fixing film's locus, preventing excessive lubricant supply to the sliding surface and minimizing leakage by using a fluorine-containing grease with a high base oil ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lubricant is applied onto the heater to decrease sliding friction resistance, then the sliding property of the fixing film is improved, but the lubricant leaks out of the end portion of the fixing film and enters the nip causing image defects
Solution Approach 1:
The invention applies different surface properties to different regions of the heater. The first region (upstream side) has a rough surface that retains lubricant, while the second region (downstream side) has a smooth surface that prevents lubricant leakage. This local differentiation allows the heater to both supply sufficient lubricant for sliding and prevent excessive lubricant from entering the nip.
Solution Approach 2:
The heater surface is divided into two distinct regions with different surface characteristics. The first region provides lubricant retention through its rough surface, while the second region provides lubricant control through its smooth surface. This segmentation allows each region to perform its specific function independently, resolving the contradiction between lubricant supply and leakage prevention.
2Quantity of substance
If grooves are provided on the heater supporting member to store lubricant, then lubricant supply is improved, but the base oil separates from the thickener at high temperature and leaks out by capillary phenomenon
Solution Approach 1:
The invention creates a localized rough surface region on the heater where lubricant can be effectively retained. This rough surface structure, created by specific heating treatment, provides capillary spaces that hold the lubricant mixture (base oil and thickener) together, preventing the base oil from separating and leaking even at high temperatures.
3Ease of operation
If the fixing film is continuously driven rotationally, then the lubricant distributes around the inner surface of the fixing film, but excessive lubricant leaks out of the end portion and moves around another surface of the fixing film
Solution Approach 1:
The heater surface is differentiated into regions with different lubricant release characteristics. The smooth second region, positioned on the downstream side, has reduced lubricant adhesion that prevents excessive lubricant from being transferred to the fixing film and subsequently leaking from its end portion, while still allowing adequate lubricant distribution.
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 design effectively reduces lubricant leakage while maintaining sliding properties, ensuring consistent image quality by controlling lubricant distribution and minimizing its escape from the fixing film's end portion.
Implementation Method 1
a heater configured to heat the fixing film
Implementation Method 2
a lubricant is interposed between the heater and an inner surface of the fixing film, so that a sliding friction resistance is decreased
Implementation Method 3
the base oil is liable to separate from the thickener. In such a case, the base oil detected from the grease stored in the grooves at the portions close to the fixing film successively leaks out of a minute gap between the inner surface of the fixing film and the heater supporting portion by a capillary phenomenon
Data Source
AI summary
A fixing device includes a fixing film, a heater for heating the fixing film, a heater holder including a heater holding portion holding the heater, and a pressing roller forming a nip between itself and the fixing film to be heated by the heater. In the nip, a toner image carried on a recording material is fixed. The heater holder includes an opposing surface which is provided on a side upstream of the heater holding portion with respect to a recording material feeding direction and which opposes the pressing roller, a lubricant holding portion provided on the opposing surface, for supplying a lubricant to between the fixing film and the heater, and a projected portion provided on the side upstream of the heater holding portion with respect to the recording material feeding direction and projecting toward the pressing roller from the opposing surface.