Image Forming Apparatus Skew Correction Loop Mechanism
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining high precision skew correction for long sheets, as the trailing end of the sheet can be displaced due to inclination, leading to sheet trouble such as bending or curling, especially when the regulator comes into contact with the sheet, and separating the regulator can result in misalignment and feeding issues.
Innovation Solution
The apparatus employs a processor-controlled system that forms a first loop with the registration roller pair and a second loop in the loop accommodator, allowing for precise skew correction by adjusting the timing of sheet refeeding, thereby minimizing the impact of sheet displacement and maintaining accurate alignment without direct contact with the regulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the regulator contacts the sheet to perform skew correction, then the skew correction can be applied, but the trailing end of long sheets becomes displaced causing sheet trouble such as bending or curling
Solution Approach 1:
The patent introduces a loop roller as an intermediary mechanism between the regulator and the sheet. The loop roller forms a loop with the sheet that absorbs displacement at the trailing end, preventing the sheet from contacting the regulator directly while still enabling skew correction at the leading end. This mediator structure resolves the contradiction by isolating the sheet from harmful regulator contact while maintaining correction functionality.
2Reliability
If the regulator is separated from the sheet to prevent sheet trouble, then sheet reliability improves, but misalignment occurs on sheets loaded on the loading tray
Solution Approach 1:
The patent segments the skew correction function into two independent parts: (1) the regulator that aligns sheets on the loading tray, and (2) the loop roller mechanism that performs skew correction during feeding. By separating these functions spatially and temporally, the regulator can maintain alignment precision without causing sheet trouble, while the loop roller handles skew correction independently.
3Productivity
If the number of stacked sheets is large, then productivity increases, but the weight becomes too heavy making it extremely difficult to restore the original state after misalignment
Solution Approach 1:
The loop roller acts as a mediator that prevents misalignment from propagating through large stacks of sheets. By absorbing displacement in the loop formation, it isolates each sheet's correction process, allowing heavy stacks to be fed without cumulative misalignment effects that would otherwise require manual restoration.
Data Source
AI summary
An image forming apparatus performs skew correction by bringing a leading end of a conveyed sheet in contact with a registration roller pair being in a stopped state and by forming a first loop with a loop roller pair, and thereafter, refeeds the sheet to an image former by adjusting timing. In a case of feeding a sheet with a length equal to or longer than a prescribed length, after having formed the first loop, the image forming apparatus forms a second loop in a loop accommodator that is disposed on an upstream side than the loop roller pair and accommodates a formed loop.