Printer Feed Roller Misaligned Stacking for Media Damage Reduction
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Solution Overview
Problem
Existing printing devices that use a separating roller and retarding roller configuration face issues with nip marks and damage to media due to strong nip pressure, and poor separation accuracy with weak nip pressure.
Innovation Solution
A printing device that forms a misaligned stacking state by repeating preliminary feed and non-feed operations with a feed roller, and includes a separating roller pair and a separating member with a sliding contact surface to improve feeding accuracy and reduce media damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strong nip pressure is applied between the separating roller and the retarding roller, then separation accuracy of the media is improved, but the media may be damaged or nip marks may remain on the medium
Solution Approach 1:
The feed roller performs preliminary feed operations before the actual feeding process to form a misaligned stacking state. By repeatedly bringing the feed roller into contact with the leading end of the media and rotating it a plurality of times, the top sheet is positioned further downstream than the underlying sheets. This preliminary alignment reduces the nip pressure needed during separation, preventing media damage while maintaining separation accuracy.
Solution Approach 2:
The feed roller acts as an intermediary mechanism between the media stack and the separating roller. It creates a controlled misaligned stacking state that facilitates easier separation with reduced nip pressure. The feed roller's repeated contact and rotation creates an air gap or separation zone that mediates the interaction between the media sheets, allowing separation without strong pressure.
2Object-affected harmful factors
If weak nip pressure is applied between the separating roller and the retarding roller, then media damage is reduced, but separation accuracy of the media deteriorates
Solution Approach 1:
The misaligned stacking state is created in advance through preliminary feed operations. By positioning the top sheet further downstream than the underlying sheets before separation occurs, the system prepares the media for easy separation with minimal nip pressure. This preliminary positioning ensures that even weak nip pressure achieves adequate separation accuracy.
3Manufacturing precision
If traditional separating roller and retarding roller configuration is used, then separation function is achieved, but device complexity increases and media damage occurs
Solution Approach 1:
The invention extracts the alignment function from the separation mechanism itself. Instead of relying solely on the separating roller and retarding roller to both align and separate the media, the feed roller is given the additional function of creating the misaligned stacking state. This separation of functions simplifies the overall device configuration while maintaining effective separation.
Solution Approach 2:
The feed roller is given multi-functionality: it not only feeds the media to the printing unit but also creates the misaligned stacking state that facilitates separation. By combining the feeding function and the alignment function in a single component, the device complexity is reduced while maintaining the separation capability.
Data Source
AI summary
A printing device includes a placement unit on which a plurality of media are stackable, a printing unit, and a feed roller that feeds the medium placed on the placement unit in a transport direction. Before starting feeding of the medium downstream in the transport direction, by repeating, a plurality of times, a preliminary feed operation of coming into contact with a first medium and rotating, and a non-feed operation of not feeding the medium, the feed roller forms a misaligned stacking state in which the first medium is disposed further downstream, in the transport direction, than at least some of the plurality of media disposed closer to the placement unit side. The feed roller feeds the first medium downstream in the transport direction from the placement unit subsequent to formation of the misaligned stacking state.