Image Stabilization Control for Transfer Bias in Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately determining and maintaining transfer output due to changes in the properties of transfer rollers, intermediate transfer members, toner, and photoreceptors over time and environmental conditions, leading to difficulties in achieving consistent image density and quality.
Innovation Solution
An image forming apparatus with an image stabilization controlling section to maintain toner image density on an intermediate transfer member and a transfer output controlling section that adjusts transfer output based on toner patch image density, with an overall controlling section that prioritizes image stabilization before transfer output control, using a power source to apply transfer bias voltage and an optical density sensor to detect and adjust toner patch image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transfer bias is determined based on pre-established relationship between developing bias and transfer bias, then control operation can be performed, but accuracy deteriorates when properties of transfer roller or intermediate transfer member change over time
Solution Approach 1:
The patent implements a feedback mechanism where the density of the toner patch image on the intermediate transfer member is detected, and this detection result is fed back to the control section. The control section then adjusts the transfer bias based on this feedback, creating a closed-loop control system that continuously adapts to changes in component properties over time.
Solution Approach 2:
The patent forms a toner patch image on the intermediate transfer member before performing the transfer output control operation. This preliminary action allows the system to detect the actual density of the transferred toner image and use this information to accurately determine the transfer bias, rather than relying on pre-established relationships that may be outdated.
2Ease of operation
If charge amount per unit area of toner image is adjusted and transfer output is reset using relationship data, then control can be performed, but accuracy deteriorates because actual density of toner image is not detected
Solution Approach 1:
The patent uses an optical density sensor to detect the actual density of the toner patch image on the intermediate transfer member. This detection provides real feedback about the actual transfer output, allowing the control section to adjust the transfer bias accurately based on measured values rather than relying solely on pre-stored relationship data between voltage and current values.
Solution Approach 2:
The patent replaces the indirect method of using relationship data (voltage/current values) with direct optical detection using an optical density sensor. This substitution allows for direct measurement of the actual toner image density, providing more accurate feedback for transfer output control.
3Ease of operation
If transfer output value is adjusted, then transfer output control can be performed, but image density control becomes difficult when developing bias or laser beam intensity changes
Solution Approach 1:
The patent implements a feedback control system where the optical density sensor continuously monitors the density of the toner patch image. When developing bias or laser beam intensity changes occur, the system detects these changes through the optical density measurement and automatically adjusts the transfer bias to compensate, maintaining consistent image density despite variations in other process parameters.
Solution Approach 2:
The patent dynamically adjusts the transfer bias parameter based on real-time detection of toner image density. By changing the transfer bias parameter in response to detected density variations, the system maintains optimal image density even when other parameters like developing bias or laser beam intensity fluctuate.
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 accurate and consistent transfer output, ensuring high-quality images even with changes in environmental conditions and equipment properties, by stabilizing toner image density and optimizing transfer output control.
Implementation Method 1
an optical density sensor to detect and adjust toner patch image density
Implementation Method 2
a transferring device to transfer the toner image onto an intermediate transfer member at a transferring section by applying a transfer bias voltage outputted by a power source
Data Source
AI summary
There is disclosed an image forming apparatus includes an image bearing member; a charging device to charge the image bearing member; an exposing device to form a latent image on the image bearing member; a developing device to form a toner image on the image bearing member; a transferring device to transfer the toner image onto an intermediate transfer member by applying a transfer bias voltage; an image stabilization controlling section for keeping a density of the toner image transferred onto the intermediate transfer member within a predetermined range; a transfer output controlling section for controlling a transfer output based on a density of a toner patch image; and an overall controlling section to control both the image stabilization controlling section and the transfer output controlling section, in such a manner that the image stabilization controlling operation is conducted preceding to the transfer output controlling operation.