Intermediate Transfer Member Charge Elimination
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Solution Overview
Problem
High-speed image forming apparatuses face challenges in maintaining uniform electric potential on intermediate transfer members, leading to image failures and uneven transfer performance, especially when the linear speed increases, and existing solutions complicate the system with insufficient charging and pressure distribution issues.
Innovation Solution
A pre-secondary transfer electric charge eliminating device with a conductive elastic counter electrode is used, where the pressure distribution is optimized to be greater at the ends than the center, ensuring uniform electric charge elimination across the intermediate transfer member, and a scorotron charger with a grid electrode and discharge electrode is employed to maintain efficient charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the linear speed of the intermediate transfer member is increased to improve productivity, then the image forming speed is improved, but the uniformity of electric potential on the intermediate transfer member deteriorates, leading to image failures and uneven transfer performance
Solution Approach 1:
The counter electrode is designed with non-uniform pressure distribution, applying greater pressure at the ends than at the center. This local variation in pressure compensates for the non-uniform electric potential distribution that occurs at high speeds, ensuring uniform electric charge elimination across the entire width of the intermediate transfer member.
2Device complexity
If a conventional counter electrode with uniform pressure distribution is used, then the structure is simple, but the electric charge elimination becomes non-uniform, causing image failures
Solution Approach 1:
The counter electrode incorporates a pressure distribution mechanism that applies different pressures to different regions. Specifically, the ends of the counter electrode exert greater pressure on the intermediate transfer member than the center region, creating a non-uniform pressure distribution that compensates for edge effects and ensures uniform electric charge elimination across the width.
3Manufacturing precision
If the pressure at the center of the intermediate transfer member is increased, then the electric charge elimination at the center is improved, but the ends experience insufficient pressure, worsening the non-uniformity
Solution Approach 1:
The counter electrode is designed to apply greater pressure at its ends than at its center. This inverted pressure distribution pattern (higher at ends, lower at center) compensates for the natural tendency of electric charge to accumulate more at the edges, achieving uniform electric charge elimination across the entire intermediate transfer member width.
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 configuration ensures consistent electric charge elimination and improved secondary transfer performance, maintaining high-quality images even at increased speeds, and prevents toner dispersion issues, achieving uniformity in two-color solid images and excellent thin-line image formation.
Implementation Method 1
a pre-secondary transfer electric charge eliminating device including a discharge electrode and a counter electrode formed by a conductive elastic member arranged at a position opposite to the discharge electrode having the intermediate transfer member in between so as to press the intermediate transfer member
Implementation Method 2
a pre-transfer charging device to charge the toner image after having been primarily transferred onto the intermediate transfer member before being secondarily transferred onto the transfer material, and which pre-transfer charging device disposes a conductive roller member arranged on the back of the intermediate transfer member opposed to the electrode of this charger and the charger whereby a counter electrode is formed. According to this method, a toner image primarily transferred onto the intermediate transfer member is charged by AC/DC corona discharging
Data Source
AI summary
A color image forming apparatus wherein the pre-secondary transfer electric charge eliminating device arranged intermediate between a primary transfer section and a secondary transfer section is provided with: a discharge electrode arranged on the side opposite to the toner carrier surface of an intermediate transfer member; and a counter electrode containing a discharge electrode and a conductive elastic member arranged at the opposed position beyond the intermediate transfer member so as to be pressed against the intermediate transfer member; wherein the pressing force of the aforementioned counter electrode against the rear surface of the intermediate transfer member is distributed in such a way that the pressure for the center of the intermediate transfer member is smaller than that for both ends thereof, in the transversal direction to the direction in which the intermediate transfer member rotates.