Image Forming Apparatus Nip Timing to Prevent Impact Blur
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Solution Overview
Problem
Image defects such as blurring occur due to fluctuations in conveyance speed and tension of recording materials in electrophotographic image forming apparatuses, particularly at the transition points between conveyance, transfer, and fixing nip portions, leading to uneven image density and elongation/contraction of text.
Innovation Solution
An image forming apparatus with a control unit that calculates the loosening amount of recording materials between nip portions and extends the conveyance interval if an image defect is predicted, based on acquired image information, to prevent impact-induced blurring during continuous printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conveyance speed difference between nip portions is increased to improve productivity, then the output speed increases, but the tension fluctuation and impact on recording material increases causing image defects
Solution Approach 1:
The control unit calculates the loosening amount of the recording material in advance before it passes through the nip portions, and determines the conveyance interval extension needed to prevent image defects. This preliminary calculation allows the system to maintain high productivity while avoiding quality issues by proactively adjusting conveyance timing.
Solution Approach 2:
The system dynamically changes the conveyance interval parameter based on calculated loosening amounts and image presence. By adjusting the conveyance interval extension according to real-time conditions, the system optimizes both productivity and image quality, extending the interval only when necessary to prevent defects.
2Manufacturing precision
If the conveyance interval is extended to prevent image defects, then image quality improves, but productivity decreases due to reduced printing speed
Solution Approach 1:
The control unit applies conveyance interval extension only to specific recording materials that have images in regions where impact would occur, rather than extending the interval for all materials. This localized approach maintains high image quality for affected materials while preserving productivity for materials without images in critical regions.
Solution Approach 2:
The system applies conveyance interval extension partially - only when and where image defects would occur - rather than applying it universally. By extending the interval only for recording materials with images in affected regions and only by the calculated necessary amount, the system achieves quality improvement without excessive productivity loss.
3Manufacturing precision
If the fixing temperature is increased to improve fixing quality, then the fixing strength increases, but the thermal expansion of the rotatable member changes causing conveyance speed fluctuation
Solution Approach 1:
The control unit uses feedback from temperature information and loosening amount calculations to dynamically adjust the conveyance interval. By monitoring the fixing temperature and its effect on rotatable member expansion, the system compensates for conveyance speed fluctuations through intelligent conveyance interval extension, maintaining both fixing quality and speed stability.
Data Source
AI summary
An image forming apparatus includes a controller controlling conveyance of first and second recording materials. The controller calculates based on an acquired length of the second recording material in the conveyance direction before feeding, a loosening amount of the second recording material between a conveyance nip and a transfer nip when the second recording material is nipped therebetween. The controller determines based on the acquired information on the image, whether an image exists in a blurring region where an image defect is generated in the image to be transferred due to an impact that occurrs when a trailing end of the second recording material with respect to the conveyance direction passes through the conveyance nip. The controller extends a conveyance interval between the first and second recording materials when it is determined that the loosening amount is a predetermined value or more and the image exists in the blurring region.