Second Spur Roller Nip Positioning for Sheet Wavy Shape Control
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Solution Overview
Problem
Existing image recording apparatuses face challenges in maintaining a wavy shape of sheets during the recording process, as second spur rollers either fail to create a recess or exert substantial loads on the sheets, leading to jamming and distortion.
Innovation Solution
An image recording apparatus with a specific arrangement of conveyance rollers, first spur rollers, and second spur rollers, where the second spur rollers overlap with the nip position and have a circular virtual outer circumference that does not overlap with the first guide surface, allowing the sheet to be caved in and maintaining a wavy shape without exerting excessive load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the second spur roller is arranged downstream of the first spur roller, then the sheet can be pushed down to form a wavy shape, but the sheet cannot be made to have a wavy shape when it is flat without being caved in between the pinching positions
Solution Approach 1:
The patent changes the spatial arrangement of the second spur roller from a downstream position to an overlapping position with the nip position in the width direction. This dimensional repositioning allows the roller to effectively interact with flat sheets and create the necessary recesses for forming wavy shapes, resolving the limitation where flat sheets could not be properly shaped.
Solution Approach 2:
The patent modifies the positional parameter of the second spur roller, specifically its location relative to the nip position. By adjusting this parameter so that the roller overlaps with the nip position in the width direction, the system achieves effective sheet deformation for both flat and caved-in sheets, thereby forming consistent wavy shapes.
2Shape
If the second spur roller is arranged upstream of the first spur roller, then the sheet can be dented to form a recess, but a substantial load is exerted to the sheet causing damage and jamming
Solution Approach 1:
The patent repositions the second spur roller in the width direction to overlap with the nip position, rather than placing it upstream in the conveyance direction. This spatial reconfiguration allows the roller to dent the sheet effectively while distributing the load, preventing excessive stress concentration that would cause sheet damage and jamming.
Solution Approach 2:
The patent positions the second spur roller to overlap with the nip position where the sheet is already being held by the conveyance rollers and first spur rollers. This preliminary positioning ensures the sheet is secured before the second spur roller applies the denting force, preventing sheet damage and jamming that would occur with upstream placement.
3Shape
If the second spur roller overlaps with the nip position in the width direction, then the sheet can be easily made wavy, but the roller may interfere with the pinching action of the conveyance rollers and first spur rollers
Solution Approach 1:
The patent configures the second spur roller with specific local characteristics: its circular virtual outer circumferential line does not overlap with the virtual straight line along the first guide surface. This local quality distinction allows the roller to overlap with the nip position for effective wavy shape formation while avoiding interference with the pinching action of the conveyance rollers and first spur rollers.
Solution Approach 2:
The patent utilizes the width direction dimension to position the second spur roller's circular outer circumference to overlap with the nip position, while simultaneously ensuring it does not interfere with the pinching action. This dimensional arrangement allows both functions to coexist without conflict.
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 apparatus effectively imparts a wavy shape to the sheet, preventing cockling and jamming, while ensuring the sheet is not damaged by regulating the angle of entry and distribution of pressure.
Implementation Method 1
Each of the plurality of second spur rollers abuts against the surface having an image recorded of the sheet that is conveyed from the platen, and pushes down an abutting portion below the uppermost end of the paper discharge roller
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; conveyance rollers arranged downstream of the recording unit in the conveyance direction to be apart from each other in a width direction orthogonal to the conveyance direction; first spur rollers arranged opposingly to the conveyance rollers respectively and configured to nip the sheet between the conveyance rollers and the first spur rollers; second spur rollers arranged between the mutually adjoining first spur rollers respectively in the width direction; and a first guide member arranged upstream of the first spur rollers and the second spur rollers in the conveyance direction; and having a first guide surface configured to guide the sheet to a nip position at which the sheet is nipped by the conveyance rollers and the first spur rollers.