Image Forming Apparatus Developing Voltage Modulation
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Solution Overview
Problem
Image forming apparatuses face challenges in achieving uniform image density due to periodic density unevenness caused by rotating components, which can lead to fogging and excessive carrier adhesion on the photosensitive drum, affecting image quality and requiring premature cleaning.
Innovation Solution
An image forming apparatus with a controller that modulates the DC component of the developing voltage based on a correction component to reduce density unevenness, while restricting this modulation to prevent fogging and carrier adhesion, using a combination of DC and AC components in the developing voltage and charging voltage to maintain optimal fogging removal voltage within a defined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the charging voltage or developing voltage is modulated to correct periodic density unevenness, then image density uniformity is improved, but fogging occurs and carrier excessively adheres to the photosensitive drum
Solution Approach 1:
The patent applies dynamic voltage modulation by superimposing a periodic correction voltage on the developing voltage to counteract density unevenness caused by rotating component irregularities. The correction voltage varies periodically at the same frequency as the rotation of the developing sleeve, photosensitive drum, or charging roller, dynamically compensating for density variations without causing fogging or excessive carrier adhesion.
Solution Approach 2:
The patent changes the voltage parameters by introducing a correction voltage component with specific amplitude and phase characteristics. The correction voltage is calculated based on the detected density unevenness pattern and applied with controlled amplitude to reduce density variation while maintaining the voltage within a range that prevents fogging and carrier adhesion.
2Manufacturing precision
If the DC component of developing voltage is modulated based on correction component to reduce density unevenness, then image quality is improved, but fogging and carrier adhesion may occur
Solution Approach 1:
The patent implements periodic action by applying a correction voltage that oscillates at the same frequency as the rotation of the developing components. This periodic voltage modulation counteracts the periodic density unevenness caused by rotational irregularities, reducing image density variation while the amplitude is controlled to prevent fogging on non-exposure regions.
Solution Approach 2:
The patent uses a feedback mechanism where density unevenness is detected during image formation, the correction voltage is calculated based on the detected unevenness pattern, and this correction voltage is then applied to the developing voltage. The feedback loop continuously adjusts the correction voltage to minimize density variation while preventing harmful effects like fogging.
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 approach effectively reduces periodic density unevenness, minimizes fogging, and suppresses excessive carrier adhesion, thereby improving image quality and extending the cleaning interval of the photosensitive drum.
Implementation Method 1
a charging device configured to charge a surface of the photosensitive member to be uniformly charged
Implementation Method 2
an exposure device configured to form an electrostatic latent image by exposing the surface of the photosensitive member
Implementation Method 3
a developing unit having a developing rotary member that forms a toner image onto the surface of the photosensitive member by causing toner included in a developer to adhere to the electrostatic latent image
Data Source
AI summary
An image forming apparatus controls a generation circuit to modulate a DC component of a developing voltage based on a first correction component such that a density unevenness is reduced. The image forming apparatus further restricts the first correction component for modulating the DC component of the developing voltage such that fogging of toner that may occur on a non-exposure region which is not exposed by an exposure unit and adhesion to a photosensitive member of carrier included in a developer are reduced.