Image-Forming Apparatus Guide Ribs and Conductive Sheet Electrostatic Control
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Solution Overview
Problem
Conventional image-forming apparatuses face difficulties in preventing the occurrence of abnormal images during the transport of recording media due to excessive or insufficient electrostatic charges on the back surface, leading to streaks or scatter, which is exacerbated by the complexity of controlling electrostatic attraction and the variability of charge conditions based on the recording medium and environment.
Innovation Solution
An image-forming apparatus with a recording-medium guide section featuring a guide member with ribs and an electrically conductive member that partially covers the guide member, creating a clearance between the ribs and the conductive member to regulate electrostatic attraction, thereby stabilizing the transport of the recording medium and reducing the occurrence of abnormal images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grounded metal sheet is used to transport the recording medium through electrostatic attraction, then transport stability is improved, but abnormal images occur due to excessive electrostatic attraction between the back surface of the recording medium and the transport guide
Solution Approach 1:
The transport guide is designed with regions of different electrostatic properties: a grounded metal sheet region for stable transport, and a non-conductive resin region to reduce excessive electrostatic attraction. This local differentiation allows the system to maintain transport stability while preventing abnormal images in different areas of the transport path.
Solution Approach 2:
A non-conductive resin portion is introduced as an intermediary material between the grounded metal sheet and the back surface of the recording medium. This intermediary reduces the excessive electrostatic attraction that causes abnormal images, while the grounded metal sheet continues to provide stable transport through controlled electrostatic attraction.
2Reliability
If the amount of static charges on the back surface of the recording medium is excessively large, then electrostatic attraction for transport is improved, but abnormal images such as streaks and scatter occur
Solution Approach 1:
The transport guide combines grounded metal sheet and non-conductive resin in specific regions to create localized electrostatic conditions. The resin portion reduces excessive electrostatic attraction that causes abnormal images, while metal sheet regions maintain sufficient attraction for stable transport.
Solution Approach 2:
The system changes the electrostatic parameters (conductivity, charge density) of the transport guide by using different materials (metal vs. resin) in different regions. This allows optimization of electrostatic attraction to prevent abnormal images while maintaining transport stability.
3Object-affected harmful factors
If a static-eliminating member is provided to eliminate static charges from the back surface, then abnormal images are reduced, but transport stability may be compromised due to insufficient electrostatic attraction
Solution Approach 1:
Rather than uniformly eliminating static charges, the transport guide uses local quality differentiation with non-conductive resin portions positioned to reduce electrostatic attraction only where it causes abnormal images, while other regions maintain sufficient attraction for transport stability.
4Object-affected harmful factors
If the transport guide is made entirely of non-conductive material, then excessive electrostatic attraction is reduced, but transport stability deteriorates
Solution Approach 1:
The transport guide combines grounded metal sheet and non-conductive resin in specific regions to create localized electrostatic conditions. The resin portion reduces excessive electrostatic attraction that causes abnormal images, while metal sheet regions maintain sufficient attraction for stable transport.
Solution Approach 2:
The transport guide uses a composite structure combining conductive metal sheet and non-conductive resin materials. This composite design allows simultaneous achievement of stable transport (through metal region) and reduction of abnormal images (through resin region).
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
The solution effectively restrains the generation of excessive electrostatic attraction, thereby minimizing the occurrence of abnormal images, especially during double-sided image formation, by maintaining appropriate electrostatic conditions and ensuring stable transport of the recording medium.
Implementation Method 1
The electrically conductive member is configured so as to cover a portion of the guide member and has opening portions through which the ribs are exposed toward the back surface of the recording medium. The electrically conductive member regulates electrostatic attraction between the guide member and the back surface of the recording medium.
Data Source
AI summary
A guide body for guiding the back surface of toner-image-bearing paper is formed from an insulating material and is disposed so as to face a paper transport path. A paper-transport-path-facing portion of the guide body, which faces the paper transport path, has guide ribs projecting upward toward the paper. A covering metal sheet is configured such that a covering portion thereof partially covers a guide surface of the paper-transport-path-facing portion which faces the paper transport path. The covering metal sheet has slits formed therein and corresponding to the guide ribs. The slits allow the guide surface to be partially exposed therethrough.