Intermediate Transfer Belt Speed Control for Image Forming Apparatus
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Solution Overview
Problem
The speed variations in the intermediate transfer belt of electrophotographic image forming apparatus, caused by shock when thick recording paper enters, lead to image quality defects like 'banding' due to uneven image density.
Innovation Solution
The image forming apparatus applies a transfer bias sequentially to multiple primary transfer members upstream until the recording medium enters the transfer position, maintaining a consistent rotational load by continuing the bias application to at least two members, thereby stabilizing the intermediate transfer belt speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thick recording paper enters the secondary transfer position, then the transfer process can be completed, but the speed of the intermediate transfer belt varies due to shock
Solution Approach 1:
The patent applies preliminary anti-action by starting the transfer bias application sequentially from upstream first transfer members before the shock occurs, and continuing it until at least two transfer members are actively transferring. This preemptive and sustained bias application counteracts the speed variations caused by thick paper entry, preventing banding defects before they occur.
Solution Approach 2:
The patent implements preliminary action by initiating the transfer bias application in advance from upstream transfer members. The control unit starts the sequential bias application before the intermediate transfer belt experiences speed variation, ensuring that the transfer process is already underway and can accommodate the shock without causing image quality defects.
2Productivity
If the speed of the intermediate transfer belt varies, then the transfer process continues, but image density varies in the moving direction causing banding
Solution Approach 1:
The patent applies continuity of useful action by maintaining the transfer bias application continuously across at least two transfer members simultaneously. This ensures that even when speed variations occur, the transfer action remains continuous and uniform across multiple points, preventing image density variations and banding while keeping the transfer process ongoing.
3Productivity
If transfer bias is applied to all transfer members simultaneously, then transfer efficiency is high, but control complexity increases
Solution Approach 1:
The patent implements segmentation by dividing the transfer bias application into sequential stages across different transfer members. Instead of applying bias to all members simultaneously, the control unit activates upstream members first and progresses downstream, reducing control complexity while maintaining effective transfer through staged activation.
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 method effectively controls speed variations in the intermediate transfer belt, preventing 'banding' and ensuring consistent image density across the transferred image.
Implementation Method 1
a plurality of first transfer members that are disposed in positions facing the image carriers, with the intermediate transfer belt being interposed therebetween, and to which a transfer bias is applied to cause the toner images to be transferred from the image carriers to the intermediate transfer belt
Data Source
AI summary
The present invention provides an image forming apparatus. The image forming apparatus includes plural image carriers, an endless intermediate transfer belt, plural first transfer members and a second transfer member. The image forming apparatus starts application of the transfer bias sequentially from the first transfer members disposed upstream and continues to apply the transfer bias to two or more of the first transfer members until the recording medium enters a transfer position where the toner images are transferred by the second transfer member.