Preregistration Mechanism for Image Forming Apparatus
Solution Overview
Problem
Existing image forming apparatuses face challenges in reducing variations in paper conveyance timing while shortening intervals between sheets, as existing techniques either increase variations in arrival timing at the registration position or introduce new issues like variations in conveyance speed due to sensor accuracy.
Innovation Solution
The image forming apparatus employs a dual conveyance path system with sensors to perform preregistration corrections, adjusting the conveyance of paper based on its source path, allowing for temporary stops and resumed conveyance to align paper arrival times, thereby reducing timing variations and shortening intervals between sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If paper conveyance intervals are shortened to achieve high productivity, then productivity is improved, but variations in paper arrival timing at the registration position increase
Solution Approach 1:
The patent performs preregistration correction in advance before the paper reaches the registration position. The conveyance unit temporarily stops the paper at a preregistration position upstream, allowing timing adjustments to be made beforehand. This preliminary action ensures that even with shortened conveyance intervals, the paper arrives at the registration position with minimal timing variation, thus maintaining both high productivity and manufacturing precision.
2Manufacturing precision
If a single conveyance path is used with preregistration correction, then paper arrival timing variation is reduced, but the conveyance interval between sheets increases
Solution Approach 1:
The patent divides the conveyance system into two separate conveyance paths (first conveyance path and second conveyance path) with different lengths. Paper sheets are alternately conveyed through these two paths. The shorter second conveyance path allows for reduced conveyance intervals, while the longer first conveyance path provides sufficient distance for effective preregistration correction. This segmentation enables both timing precision and short intervals to be achieved simultaneously.
Solution Approach 2:
The control unit dynamically selects which conveyance path to use based on the timing requirements. By alternating between the two paths, the system can optimize the conveyance interval for each sheet while ensuring that preregistration correction is performed on sheets conveyed through the longer path. This dynamic approach allows the system to maintain short overall intervals while preserving timing accuracy.
Data Source
AI summary
A first conveyance path is a path for conveying paper from a paper feed unit to a registration roller. Passage of paper on the first conveyance path is detected by a first sensor and a second sensor. The first sensor detects passage of paper upstream from the second sensor. A second conveyance path is connected to the first conveyance path downstream from a detection position of the second sensor. In response to the first sensor detecting passage of paper, first preregistration correction is performed. In response to the second sensor detecting passage of paper, second preregistration correction is performed. If a first sheet of paper is supplied from the paper feed unit, the first preregistration correction is performed on a second sheet of paper conveyed following the first sheet. If the first sheet is conveyed from the second conveyance path, the second preregistration correction is performed on the second sheet.