Image Forming Apparatus Measurement Unit for Registration Accuracy
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in achieving high precision front/back registration due to expansion/shrinkage of the recording medium caused by the fixing process, which complicates magnification correction and degrades productivity.
Innovation Solution
An image forming apparatus with a measurement unit positioned near the image forming unit to measure the recording medium's size before and after passing through, calculating the expansion ratio, and using this data to correct image data for subsequent prints, thereby improving registration accuracy without halting the conveyance process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measurement unit is positioned far from the image forming unit to measure recording medium size before fixing, then the measurement can be performed on the recording medium before it passes through the fixing apparatus, but the recording medium changes shape between measurement and image transfer, making high precision magnification correction difficult
Solution Approach 1:
The measurement unit measures the recording medium size immediately before the image forming unit processes it, capturing the dimensions at the critical moment before shape change occurs. This preliminary measurement ensures that the recorded dimensions reflect the actual size of the recording medium just before image transfer, enabling accurate magnification correction despite subsequent shape changes during conveyance.
2Manufacturing precision
If the recording medium conveyance is stopped to perform magnification correction, then high precision front/back registration can be achieved, but productivity of the image forming apparatus degrades
Solution Approach 1:
The system continuously measures the recording medium size as it passes through the measurement unit and uses this feedback information to calculate expansion/shrinkage ratios. This real-time feedback enables the system to dynamically adjust image data for magnification correction without interrupting the conveyance process, maintaining both high precision registration and continuous productivity.
Solution Approach 2:
The patent replaces the mechanical approach of stopping conveyance to perform correction with an information-based approach. Instead of physically halting the recording medium to measure and correct, the system uses sensors to capture dimensional information and processes this data through computational algorithms to achieve magnification correction continuously, eliminating the need to stop the mechanical conveyance system.
3Manufacturing precision
If the measurement unit is positioned close to the image forming unit, then the recording medium size can be measured immediately before processing, but the measurement unit must be arranged upstream of the sheet-conveyance path, complicating the apparatus layout
Solution Approach 1:
The measurement unit is designed to serve multiple functions within the image forming apparatus. It not only measures the recording medium size for magnification correction but also integrates with the existing conveyance system to provide positioning and control information. This multi-functionality reduces the need for separate dedicated components, simplifying the overall apparatus layout while maintaining measurement precision.
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 solution enables accurate front/back registration by correcting image data based on real-time measurements, enhancing precision and maintaining productivity by avoiding the need to stop the recording medium conveyance.
Implementation Method 1
a measurement unit positioned in an immediate vicinity of the image forming unit, arranged upstream of a sheet-conveyance path than the image forming unit, and configured to measure a size of the first recording medium
Implementation Method 2
an expansion ratio calculation unit configured to calculate an expansion ratio of the first recording medium based on a first size of the first recording medium obtained before the first recording medium is passed through the image forming unit and a second size of the first recording medium obtained after the first recording medium is passed through the image forming unit
Implementation Method 3
a correction unit configured to correct the image data that is used for forming another image on a second recording medium conveyed after the first recording medium based on the expansion ratio of the first recording medium
Implementation Method 4
In a case where an image forming apparatus includes a fixing apparatus, the heat applied from the fixing apparatus to a recording medium may cause the expansion/shrinkage of the recording medium
Data Source
AI summary
An image forming apparatus includes an image forming unit forming an image on a first recording medium based on image data, a measurement unit being positioned in an immediate vicinity of the image forming unit, being arranged upstream of a sheet-conveyance path than the image forming unit, and measuring a size of the first recording medium, an expansion ratio calculation unit calculating an expansion ratio of the first recording medium based on a first size of the first recording medium obtained before the first recording medium is passed through the image forming unit and a second size of the first recording medium obtained after the first recording medium is passed through the image forming unit, and a correction unit correcting the image data used for forming another image on a second recording medium conveyed after the first recording medium based on the expansion ratio.