Fixing Device Bias Member Positioning for Slip Prevention
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Solution Overview
Problem
Conventional fixing devices experience slipping of the fusing film due to reduced friction when a recording sheet passes between the fusing film and the pressure roller, leading to unsuccessful fixation of the developer image on the sheet.
Innovation Solution
A fixing device comprising a flexible tubular member, a nip member, a backup member, and a bias member, where the bias member protrudes outside the sheet width region to bias the tubular member towards the backup member, ensuring consistent friction and preventing slip, even when the sheet is conveyed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a recording sheet passes between the fusing film and the pressure roller, then the sheet can be conveyed and processed, but the friction force is reduced causing the fusing film to slip
Solution Approach 1:
The bias member is positioned only in the non-sheet width region, creating local biasing force where it is needed without interfering with sheet conveyance. This local quality approach allows the fusing film to be biased toward the pressure roller in specific areas while maintaining normal operation in the sheet passage area.
Solution Approach 2:
The fixing device is divided into functional regions: the sheet width region for conveyance and the non-sheet width region where the bias member operates. This segmentation allows independent optimization of sheet handling and fusing film positioning without mutual interference.
2Reliability
If the bias member is positioned within the sheet width region, then the fusing film can be biased effectively, but the bias member interferes with sheet conveyance
Solution Approach 1:
The bias member is strategically positioned only in the non-sheet width region, applying biasing force locally where it is needed for fusing film control without creating interference in the sheet conveyance path. This resolves the contradiction by separating the functional zones.
Solution Approach 2:
The bias member acts as an intermediary element that indirectly influences the fusing film through the nip region without directly contacting or interfering with the sheet. It mediates between the fusing film and pressure roller to maintain proper friction contact.
3Reliability
If the bias member protrudes into the sheet width region, then the fusing film is biased toward the backup member, but the bias member contacts and damages the recording sheet
Solution Approach 1:
The bias member is confined to the non-sheet width region, creating a localized biasing function that achieves fusing film positioning without extending into the sheet passage area. This prevents direct contact between the bias member and recording sheet, eliminating damage risk.
Solution Approach 2:
The bias member is positioned in advance in the non-sheet width region to establish proper fusing film tension and positioning before the sheet arrives in that region. This preliminary positioning action prevents the need for the bias member to protrude into the sheet path.
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 restrains the slip of the fusing film, ensuring reliable thermal fixation of the developer image on the recording sheet by maintaining consistent frictional contact between the fusing film and the pressure roller.
Implementation Method 1
a friction force that generates between the tubular member and the backup member
Implementation Method 2
the tubular member is configured to circularly move around the axis in accordance with the movement of the backup member due to a friction force that generates between the tubular member and the backup member
Implementation Method 3
a fixing device that thermally fixes a developing agent image transferred on a sheet
Data Source
AI summary
A fixing device includes a tubular member, a nip member, a backup member, and a bias member. The tubular member has an outer peripheral surface, an inner peripheral surface defining an internal space, and an axis defining an axis direction. The nip member is in contact with the inner peripheral surface. The backup member is opposed to the nip member and in contact with the outer peripheral surface to form a nip region for nipping a sheet conveyed in a conveying direction orthogonal to the axis direction. The backup member is configured to move in the conveying direction and the tubular member is configured to circularly move around the axis in accordance with the movement of the backup member due to a friction force generated between the tubular member and the backup member. The bias member protrudes toward the backup member through a bias region.