Corrugated Sheet Conveying Rollers for Curl Prevention
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Solution Overview
Problem
Existing image forming apparatuses experience sheet conveying failures due to curling of sheets heated by the fixing unit, which can lead to jamming issues.
Innovation Solution
The apparatus includes a transfer unit for image transfer, a fixing unit with a heating member and a pressing member to thermally fix the image, and conveying rollers that form the sheet into a corrugated shape to increase stiffness and prevent warping, along with discharge rollers to manage the sheet's conveying path effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sheet is heated by a fixing unit to fix the developing agent image, then the image fixation is achieved, but the sheet may curl and cause conveying failures
Solution Approach 1:
The conveying rollers apply a preliminary counteracting force to the sheet's curling tendency immediately after the sheet exits the fixing unit. By forming a corrugated shape that opposes the natural curling direction, the system prevents the sheet from warping excessively before it reaches the discharge rollers, thus maintaining conveying reliability while the sheet is still hot and pliable.
Solution Approach 2:
The conveying rollers physically transform the sheet's shape parameter by forming corrugations (ridges and grooves) in the sheet thickness direction. This shape modification changes the sheet's mechanical properties, increasing its stiffness and ability to resist further curling, thereby resolving the contradiction between maintaining image fixation and preventing sheet warping.
2Reliability
If conveying rollers form the sheet into a corrugated shape to prevent curling, then sheet conveying reliability is improved, but the device complexity increases
Solution Approach 1:
The conveying rollers perform multiple functions simultaneously: they convey the sheet forward, apply mechanical pressure to form corrugations, and correct sheet warping. By combining these functions into a single component, the system avoids adding separate correction devices, thus improving conveying reliability without proportionally increasing device complexity.
3Stability of the object's composition
If the sheet is conveyed with excessive curling, then the conveying path becomes unstable, but adding correction mechanisms increases the device complexity
Solution Approach 1:
The sheet correction function is merged with the existing conveying rollers rather than adding separate correction mechanisms. The same rollers that move the sheet forward also apply the mechanical force needed to form corrugations and correct warping, thereby stabilizing the conveying path without significantly increasing 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 configuration prevents or reduces sheet conveying failures by correcting warping and maintaining smooth sheet conveyance, even when sheets are excessively warped due to heat application.
Implementation Method 1
a fixing unit comprising a heating member, which is configured to thermally fix the developing agent image onto the sheet
Implementation Method 2
The at least one pair of conveying rollers is configured to convey the sheet toward the at least one discharge rollers in the conveying direction and to form the sheet into a corrugated shape having at least one of a ridge portion and a groove portion in a sheet thickness direction
Data Source
AI summary
An image forming apparatus includes a transfer unit configured to transfer a developing agent image onto a sheet, a fixing unit configured to fix the developing agent image onto the sheet, a discharge tray configured to receive the sheet having the developing agent image thereon, at least one pair of discharge rollers disposed downstream of the fixing unit in a conveying direction and configured to discharge the sheet toward the discharge tray, and at least one pair of conveying rollers disposed at a conveying path extending between the fixing unit and the at least one pair of discharge rollers. The at least one pair of conveying rollers is configured to convey the sheet toward the at least one discharge rollers in the conveying direction and to form the sheet into a corrugated shape having at least one of a ridge portion and a groove portion in a sheet thickness direction.