Bidirectional Conveyance and Retaining Mechanism for Continuous Paper
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Solution Overview
Problem
Image forming apparatuses face issues when conveying continuous paper that has passed through a fixing nip to the upper stream side of a transfer nip, leading to deformation, uneven toner images, and adhesion of glue to the transfer belt, complicating the system configuration.
Innovation Solution
An image forming apparatus with a conveying portion that can move the continuous recording medium in either direction, an image forming portion for forming toner images, a fixing portion for heating and fixing the images, a retaining portion between the transfer and fixing nips to prevent deformation, and a control portion that manages the conveying direction to prevent damage from the fixing nip's heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the continuous paper is conveyed in a small amount in the paper conveying direction during stop of print job, then the continuous paper is prevented from being damaged due to heating at the fixing nip, but the continuous paper becomes wasted paper
Solution Approach 1:
The patent applies reverse conveyance by conveying the continuous paper in a direction opposite to the paper conveying direction (second conveying direction) to the upper stream side of the transfer nip before the next print job starts. This allows the paper that would otherwise be wasted to be repositioned and reused in the subsequent printing operation.
2Loss of substance
If the continuous paper is conveyed in the direction opposite to the paper conveying direction to the upper stream side of the transfer nip, then the waste paper is reduced, but the heat of the continuous paper heated at the fixing nip is transmitted to the transfer roller and transfer belt causing damage
Solution Approach 1:
The patent introduces a retaining portion positioned between the transfer nip and the fixing nip that retains a part of the continuous paper. This preliminary action prevents the heated paper from reaching the transfer roller and transfer belt during reverse conveyance, thereby protecting these components from heat damage while still allowing waste paper reduction.
Solution Approach 2:
The retaining portion acts as an intermediary element between the heated continuous paper and the transfer components. It intercepts the hot paper during reverse conveyance and prevents direct contact with the transfer roller and transfer belt, thus mediating the harmful thermal interaction.
3Loss of substance
If a mechanism for conveying the continuous paper in the direction opposite to the paper conveying direction is provided, then the waste paper is reduced, but the image forming apparatus becomes complicated
Solution Approach 1:
The patent makes the conveying portion multi-functional by enabling it to convey the continuous paper in both the paper conveying direction (first conveying direction) and the opposite direction (second conveying direction). This universal conveying capability allows the same mechanism to perform both normal paper transport and reverse conveyance for waste reduction, avoiding the need for separate mechanisms.
Solution Approach 2:
The patent combines the reverse conveyance function with the existing conveying portion and control portion. Instead of adding a separate mechanism, the control portion is enhanced to manage bidirectional conveyance, merging multiple functions into existing components and thereby reducing overall system 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 configuration simplifies the system by allowing the continuous paper to be conveyed in the opposite direction during temperature changes, preventing deformation and ensuring proper image transfer without damaging the transfer nip or adhering glue, thus reducing waste and maintaining image quality.
Implementation Method 1
a fixing portion configured to heat the continuous recording medium, at a fixing nip
Implementation Method 2
a retaining portion provided between the transfer nip and the fixing nip in the first conveying direction, the retaining portion configured to retain a part of the continuous recording medium
Data Source
AI summary
An image forming apparatus includes: a conveying portion configured to convey a continuous recording medium in a first conveying direction or in a second conveying direction opposite to the first conveying direction; an image forming portion configured to form a toner image on the continuous recording medium at a transfer nip; a fixing portion provided on a lower stream side of the image forming portion in the first conveying direction and configured to heat and fix the toner image formed on the continuous recording medium, at a fixing nip; a retaining portion provided between the transfer nip and the fixing nip in the first conveying direction and configured to retain a part of the continuous recording medium; and a control portion configured to control the conveying portion to convey a passed portion that has passed through the fixing nip and control the retaining portion to retain the passed portion.