Double-Sided Image Position Correction in Electrophotographic Apparatus
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face challenges in achieving precise alignment and size matching of images on both sides of a recording sheet, particularly due to thermal contraction and cutting errors, leading to inaccuracies in positional shift and magnification correction, which are difficult to correct manually and require significant manpower and time.
Innovation Solution
The image forming apparatus includes a position detecting device that forms a detection image with a frame line on both sides of the recording sheet, measuring leading and trailing end margins and image lengths to calculate positional shifts and magnification errors, allowing for automated correction of image positions and sizes based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurement and correction methods are used to correct positional shifts and magnification errors, then correction accuracy can be improved, but the workload and time required increase significantly
Solution Approach 1:
The image forming apparatus automatically performs measurement and correction of positional shifts and magnification errors using its own imaging and processing capabilities, eliminating the need for external manual measurement and correction operations
Solution Approach 2:
The patent replaces manual mechanical measurement and correction operations with an automated optical-electronic system that uses imaging capture, coordinate extraction, and computational algorithms to achieve precise automatic correction
2Measurement precision
If detection marks are used to measure image position and magnification, then correction accuracy is improved, but the complexity of the detection and measurement process increases
Solution Approach 1:
The patent extracts only the essential measurement information (coordinates of detection mark endpoints) from the captured image, separating the measurement function from the entire imaging process and simplifying the overall detection and measurement workflow
Solution Approach 2:
The patent creates a digital copy of the detection mark positions through coordinate extraction from the captured image, enabling automated calculation of positional shifts and magnification errors without requiring complex physical measurement procedures
3Productivity
If images are formed on both sides of recording sheets in sequence, then productivity is improved, but positional alignment between first side and second side images becomes difficult to control
Solution Approach 1:
The patent uses detection marks imaged on both sides of recording sheets to provide feedback information about positional shifts and magnification errors, enabling automatic correction that maintains precise alignment while sustaining high productivity in double-sided image formation
Solution Approach 2:
The patent performs preliminary imaging of detection marks on the first side of recording sheets before forming production images, using this preliminary information to pre-calculate correction parameters that ensure accurate alignment when images are formed on the second side
Data Source
AI summary
An image forming apparatus includes an image forming device configured to form a first image on a first side of a recording medium and a second image on a second side of the recording medium, a position detector configured to detect respective positions of the first and second images, and a controller configured to perform, based on detection results obtained by the position detector, at least one of an image position correction by matching the first and second images and a magnification error correction by calculating and correcting a magnification error of one of the first and second images relative to the other. A program product used in the image forming apparatus includes a method of forming the first image and the second image, detecting the respective positions of the first and second images, and matching a position or a size of the first and second images.