Intermediary Transfer Belt Charge Control for Embossed Paper
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Solution Overview
Problem
In image forming apparatuses using the electrophotographic intermediary transfer type, the increase in toner charge on the intermediary transfer belt due to electric discharge between the belt and the photosensitive drum downstream of the primary transfer portion leads to difficulties in secondary transfer, particularly on uneven surfaces like embossed paper, and can impair primary transferability when using potential regulating members.
Innovation Solution
An image forming apparatus with a photosensitive member, an intermediary transfer belt, a primary transfer member, an electrode member downstream of the primary transfer portion, and a control system that applies biases to these components to manage the transfer bias and current flow, ensuring effective suppression of electric discharge while maintaining primary transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a potential regulating member is placed downstream of the primary transfer portion on the intermediary transfer belt to suppress electric discharge, then secondary transferability is improved, but leakage current occurs from the primary transfer portion to the potential regulating member, reducing primary transfer current and impairing primary transferability
Solution Approach 1:
The patent applies different bias polarities to different regions: opposite polarity bias to the primary transfer member for efficient toner transfer, and same polarity bias to the potential regulating member for suppressing electric discharge. This local differentiation of electrical properties allows simultaneous optimization of both primary and secondary transfer processes without interference between them.
Solution Approach 2:
The potential regulating member acts as an intermediary element between the primary transfer portion and the secondary transfer portion. By introducing this intermediate component with specific bias control, the patent mediates the electrical field distribution to prevent direct electric discharge while maintaining the necessary transfer currents in the primary transfer region.
2Reliability
If the charge amount of toner on the intermediary transfer belt is increased to improve transfer to embossed paper, then transferability to uneven surfaces is improved, but graininess of the image deteriorates and uniform transfer becomes difficult
Solution Approach 1:
The patent dynamically adjusts the electrical parameters (bias voltages and currents) of both the primary transfer member and the potential regulating member based on detected transfer conditions. By changing these parameters in real-time, the system optimizes the charge amount on the intermediary transfer belt to match the specific requirements of different recording materials, preventing both insufficient transfer and image graininess.
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 improves secondary transferability by reducing toner charge on the intermediary transfer belt, enhancing image quality on uneven surfaces while maintaining primary transfer efficiency by correcting the primary transfer bias based on detected current and voltage values.
Implementation Method 1
toner images formed on the photosensitive drums are primarily transferred electrostatically onto the intermediary transfer belt
Implementation Method 2
it is effective to place a potential regulating member, which is a conductive electrode member, downstream of the primary transfer portion and on the inner peripheral surface of the intermediary transfer belt, and to apply the bias of the same polarity as the charge polarity of the photosensitive drum to this potential regulating member
Implementation Method 3
a first detecting portion configured to detect a current flowing through or a voltage applied to the primary transfer member; a second detecting portion configured to detect a current flowing through or a voltage applied to the electrode member
Data Source
AI summary
An image forming apparatus includes a photosensitive member charged to a predetermined polarity, an intermediary transfer belt, a primary transfer member forming a primary transfer portion, an electrode member in contact with the inner peripheral surface of the photosensitive member on a downstream side, first and second detecting portion to detect a current flowing through or a voltage applied to the primary transfer member and the electrode member, respectively, and a control portion, during non-image formation, to execute a setting operation in which the transfer bias to be set during image formation is set. In executing the setting operation, the control portion sets the transfer bias based on a first detecting result detected by the first detecting portion while a voltage is applied to the primary transfer member and a second detecting result detected by the second detecting portion while the voltage is applied to the primary transfer member.