Duplex Printing Alignment via Shrinkage Compensation
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Solution Overview
Problem
Image forming apparatuses face challenges in maintaining size consistency and alignment between front-side and back-side images during duplex printing due to paper shrinkage, leading to suboptimal finish quality.
Innovation Solution
The apparatus employs a control device with a processor to perform size reduction and alignment adjustments of back-side images based on predetermined shrinkage ratios, ensuring that both images are equal in size and aligned properly on the paper sheet, using a combination of image processing and correction techniques to set optimal print start positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If duplexing is performed by forming images on both sides of recording paper sheet using conventional methods, then productivity is improved by enabling double-sided printing, but manufacturing precision deteriorates due to misalignment and size discrepancy between front-side and back-side images caused by paper shrinkage
Solution Approach 1:
The patent applies preliminary action by predicting the paper shrinkage amount before duplex printing based on the type of recording paper sheet, and pre-calculating the print start position for the back side to compensate for the shrinkage. This ensures that even after the paper shrinks during drying, the back-side image will be properly aligned with the front-side image, thus resolving the misalignment issue while maintaining productivity
Solution Approach 2:
The patent changes the print start position parameter for the back side based on the predicted shrinkage amount. By adjusting this parameter according to the paper type and shrinkage characteristics, the system compensates for the size reduction of the paper, ensuring that the back-side image aligns correctly with the front-side image after duplexing
2Manufacturing precision
If image size is reduced to compensate for paper shrinkage, then manufacturing precision is improved by achieving better alignment, but loss of information occurs due to reduction in image size
Solution Approach 1:
Instead of reducing the image size, the patent changes the print start position parameter for the back side to account for paper shrinkage. This approach maintains the original image size and quality while achieving proper alignment by adjusting where the image is positioned on the shrunk paper, thus avoiding any loss of information
3Manufacturing precision
If print start position is adjusted to compensate for shrinkage, then manufacturing precision is improved by achieving aligned images, but device complexity increases due to additional control calculations
Solution Approach 1:
The patent adjusts the print start position parameter for the back side based on predicted shrinkage, which requires additional control calculations. However, this parameter adjustment is performed through software processing in the control device without requiring any additional hardware components, thus achieving improved alignment while keeping the increase in device complexity minimal and acceptable
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 approach effectively eliminates misalignment and size discrepancies between front-side and back-side images, enhancing the finish quality of printed materials without requiring hardware changes, thus maintaining a simple and cost-effective structure.
Implementation Method 1
a general ink-jet image forming apparatus forms an image on the front side of a recording paper sheet by applying ink to the front side, allows the applied ink to dry, and then forms an image on the back side of the recording paper sheet by applying ink to the back side thereof. In doing so, the recording paper sheet shrinks in the process of drying of the ink.
Data Source
AI summary
An image forming apparatus includes an image forming device, a controller, and an image processor that creates a reduced-size image from an original-size image of back-side image data at a size reduction ratio according to a magnification ratio from a first shrunk state of a recording paper sheet with only a front-side image formed to a second shrunk state after formation of the front-side and back-side images so that the back-side and front-side images on the sheet match respective original sizes of front-side image data and back-side image data. The controller allows the image forming device to form the front-side image, sets, based on a margin formed by the size reduction, a print start position for a back side of the sheet where the front-side and back-side images on the sheet are locationally aligned, and then allows the image forming device to form the reduced-size image as the back-side image.