Retractable Sheet Discharging Unit for Jam Prevention
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Solution Overview
Problem
Existing image forming apparatuses face issues with jamming due to thin sheets of recording media getting stuck to rotational members, leading to interruptions in the image forming process, despite the use of air blowing mechanisms, as these mechanisms often lack sufficient space for effective removal of jammed sheets.
Innovation Solution
An image heating apparatus with a retractable sheet discharging unit equipped with an air nozzle and conveyance rollers that can pivot away from the fixation roller, creating a larger space for jammed sheet removal, and utilizing compressed air to separate sheets from the rotational members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air blowing mechanism is provided in the adjacencies of the rotational members to blow air at the rotational members, then sheet separation from rotational members is improved, but the space for removing jammed sheets becomes insufficient
Solution Approach 1:
The sheet discharging unit is made movable relative to the image heating unit, transitioning between a first position during image fixing and a second position for jammed sheet removal. This dynamic repositioning allows the system to optimize for both sheet separation reliability during operation and ease of jammed sheet removal when needed.
Solution Approach 2:
The sheet discharging unit including the air blowing mechanism is extracted as a separate movable component from the main image heating unit. This extraction allows the air blowing mechanism to be repositioned away from the rotational members when jammed sheets need removal, creating sufficient space for manual intervention while maintaining its sheet separation function during normal operation.
2Reliability
If the air blowing mechanism is disposed in the adjacencies of the rotational member, then sheet separation is effective, but it becomes difficult to find space on the downstream side of the nip for removing jammed sheets
Solution Approach 1:
The sheet discharging unit is designed to move between positions, allowing the air blowing mechanism to be relocated from the adjacency position during image fixing to a retracted position during jammed sheet removal. This dynamic repositioning creates sufficient space in the downstream area when needed while maintaining effective sheet separation during normal operation.
Solution Approach 2:
The solution addresses the spatial conflict by introducing movement in an additional dimension - the sheet discharging unit moves along the conveyance direction rather than only in the radial direction near the rotational members. This dimensional change allows effective sheet separation during operation while creating space for jammed sheet removal when the unit is retracted.
3Ease of operation
If a retractable sheet discharging unit is provided that can pivot away from the fixation roller, then space for jammed sheet removal is increased, but device complexity increases
Solution Approach 1:
The sheet discharging unit incorporates a simple pivoting mechanism that allows it to rotate between a first position adjacent to the fixation roller during image fixing and a second retracted position for jammed sheet removal. This dynamic repositioning capability is implemented with relatively simple mechanical components, balancing improved ease of operation with acceptable device complexity.
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 design effectively prevents jamming by ensuring easy separation of sheets from the rotational members and provides a sufficient space for manual removal of jammed sheets, minimizing interruptions in the image forming process.
Implementation Method 1
an air discharging portion configured to discharge air for separating the sheet from the rotatable member
Data Source
AI summary
An image heating apparatus includes: an image heating unit including a pair of rotatable members between which a sheet is nipped and fed while heating a toner image thereon; and a retracting unit retractable from the image heating unit. The retracting unit includes an air discharging portion configured to discharge air for separating the sheet from the rotatable member, and a feeding portion provided with a pair of rotatable members and configured to nip and feed therebetween the sheet heated by the image heating unit.