Fuser Belt Fixing Device Decurling Recording Media
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the curling of recording media due to moisture expansion and contraction in the fixing process leads to malfunction or failure, as they tend to wind around the fuser member, causing deformation and disrupting the fixing process.
Innovation Solution
A fixing device with a rotatable, flexible fuser belt and a fuser pad, where a reinforcing member restricts displacement and a heat pipe with radiant heaters efficiently heats the belt, combined with a pressure member to form a fixing nip, ensuring uniform heat and pressure distribution, preventing curling and ensuring reliable imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fixing device with heated fuser member and pressure member is used, then toner image fixing is achieved, but recording medium curls and winds around the fuser member causing malfunction
Solution Approach 1:
The patent applies preliminary anti-action by introducing a decurling member that exerts a force opposite to the curling tendency of the recording medium. This decurling member is positioned to contact the leading edge of the recording medium before it enters the fixing nip, preventing the curling that would otherwise occur during the fixing process. By counteracting the harmful curling effect in advance, the system maintains reliable operation without the medium winding around the fuser member.
2Manufacturing precision
If heat and pressure are applied to fix toner, then toner melts and sets on recording medium, but moisture content expansion causes curling deformation
Solution Approach 1:
The patent introduces a decurling member as an intermediary element between the recording medium and the fixing process. This decurling member acts as a mediator that compensates for the shape changes caused by moisture expansion during heating. By positioning this intermediary component to contact and guide the leading edge of the recording medium, it prevents the thermal-induced curling while allowing the toner fixing process to proceed with high quality.
3Productivity
If recording medium enters fixing nip, then toner is fused and pressed, but medium curls toward fuser member causing wind around
Solution Approach 1:
The patent implements preliminary action by equipping the decurling member with a leading edge contact surface that engages the recording medium before it fully enters the fixing nip. This preliminary contact prevents curling from developing during the fixing process, ensuring that the medium proceeds smoothly through the device without winding around components. The preliminary decurling action maintains both productivity and operational stability.
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 prevents curling of the recording media, maintains uniform nip pressure, and ensures reliable imaging quality by efficiently heating the fuser belt and applying consistent pressure, thus preventing imaging defects and device failures.
Implementation Method 1
a heat pipe with radiant heaters efficiently heats the belt
Implementation Method 2
the fuser member heats the recording medium to fuse and melt the toner particles
Implementation Method 3
the pressure member presses the recording medium against the fuser member to cause the molten toner to settle onto the recording medium
Implementation Method 4
a recording medium tends to curl or bend toward the fuser member, in a manner similar to that of a bimetallic strip, owing to expansion and contraction of its moisture content under heat
Data Source
Figure 1
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Figure 4~5
AI summary
A fixing device includes a rotatable, flexible fuser belt, a heater, a fuser pad, and a pressure member. The fuser belt is looped into a generally cylindrical configuration. The heater is disposed adjacent to the fuser belt to heat the fuser belt. The fuser pad is disposed inside the loop of the fuser belt, and has an outer peripheral surface thereof formed in a generally concave configuration. The pressure member is disposed opposite the fuser pad with the fuser belt interposed between the fuser pad and the pressure member. The pressure member presses in a load direction against the outer peripheral surface of the fuser pad through the fuser belt to form a fixing nip therebetween. The fuser pad includes, along the outer peripheral surface thereof, a protruding portion and an inwardly curved portion adjoining the protruding portion to face an outer circumferential surface of the pressure member.