Toner Transfer via Electrostatic Edge Effect in Image Forming Apparatus
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses face issues with abnormal noise due to insufficient toner at the contact portion between the photoconductive body and the cleaner, especially when only monochrome printing is performed without additional toner cartridges, leading to reduced toner supply to other process units.
Innovation Solution
The apparatus includes a belt and two process units with chargers, exposers, developers, and transferers, where the first process unit forms a toner image and transfers it onto the belt, and the second unit positions an electrostatic latent image to coincide with the toner image, allowing toner transfer without a reverse transfer bias, thus eliminating the need for a power supply for reverse transfer bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If reverse transfer bias is applied to transfer toner from the first process unit to the second process unit, then toner supply is effective, but power consumption increases and requires additional power supply components
Solution Approach 1:
The patent extracts and eliminates the power supply component for reverse transfer bias from the system. Instead of using electrical power to drive reverse transfer, the invention utilizes the natural electrostatic field generated by the charger during normal charging operations to achieve toner transfer, thereby removing the need for additional power consumption and power supply components.
Solution Approach 2:
The charger serves multiple functions: it charges the photoconductive body for normal image formation and simultaneously generates the electrostatic field necessary for toner transfer to the second process unit. This multi-functionality eliminates the need for separate power supply components dedicated solely to reverse transfer operations.
2Reliability
If reverse transfer bias power supply is included, then toner transfer is reliable, but device complexity increases
Solution Approach 1:
The patent removes the reverse transfer bias power supply component from the system entirely. The reliable toner transfer is achieved by utilizing the electrostatic field naturally generated by the charger during normal charging operations, combined with the edge effect at the boundaries of the electrostatic latent image, eliminating the need for additional power supply components and reducing device complexity.
Solution Approach 2:
The charger provides the electrostatic field needed for toner transfer as a byproduct of its normal charging function. The system uses its own existing operational fields and components to achieve toner transfer, rather than requiring separate dedicated power supply components, thereby simplifying the overall device architecture.
3Productivity
If monochrome printing is performed consecutively with only monochrome toner cartridge, then productivity is maintained, but toner becomes insufficient at contact portions of other process units causing squeaking noise
Solution Approach 1:
The patent performs preliminary toner transfer to the second process unit's photoconductive body before the cleaner contacts it. By using the electrostatic field from the charger and the edge effect to transfer toner in advance, the system ensures that sufficient toner is present at the contact portions before cleaning operations begin, preventing squeaking noise during consecutive monochrome printing operations.
Solution Approach 2:
The electrostatic latent image and its edge effect serve as an intermediary mechanism for toner transfer. Instead of direct mechanical or electrical intervention, the system uses the electrostatic field distribution, particularly at the edges of the latent image, as a mediator to transport toner from the first process unit to the second process unit, ensuring adequate lubrication at contact portions.
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 solution enables effective toner supply from one process unit to another, reducing noise and power consumption, and preventing squeaking, even in systems without a reverse transfer bias power supply, by utilizing the edge effect of the electric field for toner transfer.
Implementation Method 1
a first charger configured to charge a surface of the first photoconductive body
Implementation Method 2
a first exposurer configured to expose the charged surface of the first photoconductive body thereby forming an electrostatic latent image
Implementation Method 3
a first developer configured to develop, with toner, the electrostatic latent image formed on the surface of the first photoconductive body
Implementation Method 4
a first transferer configured to transfer, onto the belt, the toner image formed on the surface of the first photoconductive body
Data Source
AI summary
An image forming apparatus includes a belt, a first process unit, a second process unit, and a controller configured to form a toner image based on a first pattern on a first photoconductive body of the first process unit. In addition, the controller is configured to transfer the toner image onto the belt, form an electrostatic latent image based on a second pattern on a second photoconductive body of the second process unit such that the electrostatic latent image formed on the second photoconductive body positionally coincides with the toner image transferred onto the belt in a contact position where the second photoconductive body contacts the belt, and convey the electrostatic latent image formed on the second photoconductive body to the contact position without developing the electrostatic latent image with toner.