Developing Roller Contact Control for Toner Waste Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image forming apparatuses face challenges in shortening the first print out time (FPOT) while preventing wasteful toner consumption, particularly due to the need for separate developing roller and photosensitive drum contact timing during automatic power control (APC) to avoid toner transfer during APC operations.
Innovation Solution
The image forming apparatus includes an exposure device for forming an electrostatic latent image and a developing device that can switch between contact and separation states, allowing the developing device to change to a contact state only when a predetermined portion of the image bearing member is at the developing position during APC, with a second developing voltage applied to prevent toner transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the developing roller contacts the photosensitive drum after completion of APC, then wasteful toner consumption is prevented, but first print out time (FPOT) increases
Solution Approach 1:
The developing roller is designed to dynamically switch between contact and separation states based on operational phase. During APC, the developing roller is separated from the photosensitive drum to prevent toner consumption. During image formation, the developing roller contacts the photosensitive drum to enable normal development. This dynamic state change resolves the contradiction by allowing both APC (with separation) and image formation (with contact) to occur at appropriate times.
2Device complexity
If the developing roller constantly contacts the photosensitive drum, then device complexity is reduced, but wasteful toner consumption occurs during APC
Solution Approach 1:
The developing device incorporates a mechanism to change between contact and separation states. The developing roller can be moved to a separation position during APC and to a contact position during image formation. This dynamic capability adds some structural complexity but prevents significant toner waste, making the overall system more efficient.
3Loss of time
If the developing roller contacts the photosensitive drum during APC, then first print out time is shortened, but toner is uselessly consumed and fogging occurs
Solution Approach 1:
The system dynamically controls the contact state between the developing roller and photosensitive drum based on the operational phase. During APC, the developing roller is separated to prevent toner transfer and fogging. During image formation, the developing roller contacts the photosensitive drum to enable proper development. This dynamic control eliminates harmful toner transfer during APC while maintaining short FPOT.
4Loss of substance
If a mechanism for separating the developing roller from the photosensitive drum is added, then toner consumption is prevented, but device complexity increases
Solution Approach 1:
The developing device incorporates a separation mechanism that allows the developing roller to be moved between contact and separation positions. This mechanical dynamic capability enables the system to prevent toner consumption during APC by separating the developing roller from the photosensitive drum, while maintaining relatively simple overall device architecture.
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 reduces FPOT and prevents wasteful toner consumption by ensuring the developing roller contacts the photosensitive drum after APC adjustments, maintaining a potential difference that prevents toner transfer and reduces the risk of fogging.
Implementation Method 1
an exposure device configured to expose the image bearing member to light to form an electrostatic latent image on the image bearing member
Implementation Method 2
a developing device configured to include a toner bearing member for bearing toner, to change between a contact state where the image bearing member and the toner bearing member are in contact with each other and a separation state where they are separated from each other, and to develop the electrostatic latent image by toner on the toner bearing member in the contact state
Data Source
AI summary
An image forming apparatus includes an exposure device having an adjustment period for adjusting an output while exposing a photosensitive drum to light prior to image formation and a developing device. The developing device is configured to change between a contact state where the photosensitive drum and a developing roller are in contact with each other and a separation state where they are separated from each other. The developing device changes from the separation state to the contact state when a portion on the photosensitive drum exposed to light in the adjustment period of the exposure device is at a developing position.