Wavy Sheet Guide Mechanism for Inkjet Printer Jam Prevention
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Solution Overview
Problem
In ink-jet recording apparatuses, the phenomenon of cockling occurs when ink adheres to a sheet, causing it to swell and potentially lead to paper jams or clogs due to the sheet being in a wavy state, which can result in damage and disruption of the image recording process.
Innovation Solution
An image recording apparatus is designed with a wavy shape applying mechanism and guide member that includes first and second spur rollers and guide surfaces, allowing the sheet to be in a wavy state while preventing large loads on the sheet's end portions by guiding it through inclined surfaces, thus preventing paper jams and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet is allowed to be in a wavy state by the first wavy shape applying mechanism, then the occurrence of cockling is suppressed, but the end portion of the sheet may leap up to abut against the inclined surface of the guide member causing paper jam or damage
Solution Approach 1:
The guide member is divided into multiple guide surfaces (first guide surface, second guide surface, third guide surface) with different inclinations. The first guide surface has a smaller inclination angle to gently guide the wavy sheet, while the second and third guide surfaces have larger inclination angles to handle the sheet after the wavy state is applied. This segmentation allows the system to manage the sheet's wavy state without causing it to leap up and jam.
Solution Approach 2:
Different regions of the guide member are assigned different inclination angles based on the local requirements of sheet handling. The first guide surface positioned upstream has a smaller inclination angle suitable for guiding sheets in a wavy state, while downstream guide surfaces have larger inclination angles. This local differentiation ensures that each region of the guide member optimally handles the sheet at that specific position.
2Productivity
If the inclined surface of the guide member is made steeper to improve conveyance efficiency, then the sheet is guided more effectively, but large load is applied to the end portion of the sheet causing paper jam or damage
Solution Approach 1:
The guide member features locally differentiated inclination angles where the first guide surface has a smaller inclination angle to reduce load on the sheet's end portion, while subsequent guide surfaces have larger inclination angles to maintain conveyance efficiency. This local quality variation allows the system to protect sheet integrity in critical areas while maintaining overall productivity.
Solution Approach 2:
The first guide surface with a smaller inclination angle is positioned upstream to preliminarily guide the sheet into the wavy shape applying mechanism in a controlled manner. This preliminary gentle guidance prevents the sheet from being subjected to large loads before it is properly positioned for the steeper downstream guide surfaces, thereby preventing paper jam or damage.
Data Source
AI summary
An image recording apparatus includes a recording unit configured to record an image on a sheet conveyed in a conveyance direction; a first wavy shape applying mechanism provided downstream in the conveyance direction from the recording unit and configured to allow the sheet to be in a wavy state in a width direction; and a guide member configured to guide the sheet to the first wavy shape applying mechanism. The first wavy shape applying mechanism includes first spur rollers configured to abut against a first surface of the sheet respectively; abutment members provided between the mutually adjoining first spur rollers respectively and configured to abut against a second surface of the sheet; and second spur rollers configured to abut against the first surface of the sheet downstream of the first spur rollers in the conveyance direction.