Image Forming Apparatus Sheet Deviation Correction
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Solution Overview
Problem
Image forming apparatuses face challenges in correcting sheet paper deviations due to limitations in the moving range of registration rollers and proximity of deviation detection and correction systems to the image forming portion, leading to variations in image writing positions and sheet movement during ejection.
Innovation Solution
The apparatus includes a first deviation detection portion upstream of the image forming portion, a pair of registration rollers downstream with adjustable movement, and a second deviation detection portion further downstream, with a control system that adjusts the image writing position and registration roller movement to correct deviations within the rollers' adjustable range, ensuring accurate alignment and minimizing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the deviation detection portion and moving portion are provided near the image forming portion to perform deviation correction, then the deviation correction function can be implemented, but the time available for image processing becomes too short causing variations in image writing position and sheet movement
Solution Approach 1:
The patent divides the deviation correction process into two separate functions: (1) a first deviation detection portion that detects sheet position upstream and adjusts image writing position, and (2) a second deviation detection portion near the image forming portion that performs fine-adjustment correction with registration rollers. This segmentation allows early correction of large deviations while reserving time for final precision correction, resolving the time constraint contradiction.
Solution Approach 2:
The first deviation detection portion performs preliminary correction of image writing position based on upstream sheet position detection. This preliminary action handles the bulk of deviation correction before the sheet reaches the image forming portion, allowing the second correction system to operate within adequate time for precise adjustment without causing position variations.
2Manufacturing precision
If the pair of registration rollers are used to move the sheet of paper for deviation correction, then the sheet position can be adjusted, but the moving amount is limited by the moving range of the registration rollers making it difficult to correct large deviations
Solution Approach 1:
The patent segments the correction system into two parts with different capabilities: the first deviation detection portion handles large-range corrections by adjusting image writing position (software/virtual correction), while the second deviation detection portion handles small-range precision corrections by physically moving the sheet with registration rollers. This segmentation enables both wide adaptability and high precision to coexist.
Solution Approach 2:
The first deviation detection portion acts as an intermediary that pre-corrects large deviations through image writing position adjustment, reducing the burden on the registration rollers. This intermediary correction allows the registration rollers to focus on fine-tuning within their limited moving range, effectively expanding the overall correction capability beyond what the rollers could achieve alone.
Data Source
AI summary
In an image forming apparatus, a first deviation detection portion detects an amount of deviation of a sheet of paper in relation to a reference position of an edge of the sheet of paper. A control portion determines whether or not an amount of deviation detected by the first deviation detection portion exists within a moving adjustment range of a pair of registration rollers in the second control and performs a first control to correct the reference position of the edge of the sheet of gaper before the image is formed when the amount of deviation exceeds the moving adjustment range of the pair of registration rollers. A second deviation detection portion detects an amount of deviation of the sheet of paper just before the image is formed in relation to a reference position of the edge of the corrected sheet of paper.