Image Forming Apparatus Density Stabilization
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Solution Overview
Problem
In electrographic system image forming apparatuses, maintaining consistent print image density during long printing sessions is challenging due to the need to interrupt normal printing to measure developer density, leading to potential differences in print quality over time.
Innovation Solution
An image forming apparatus that includes a photosensitive drum, charge and development rollers, an exposure unit, and sensors to detect physical quantities related to developer density and rotations, allowing for real-time adjustments of development and supply voltages to stabilize print density without interrupting printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If developer density is measured by interrupting normal printing to measure patch pattern density, then measurement can be performed, but printing continuity is broken and print image density cannot be stabilized during long printing
Solution Approach 1:
The patent extracts the measurement function from the printing process by using a separate no-printing developer image area on the developer carrier. This allows density measurement to be performed independently without interrupting the printing workflow, as the measurement is done on a dedicated test area while normal printing continues on other areas.
Solution Approach 2:
The patent creates a no-printing developer image in advance on the developer carrier before normal printing occurs. This preliminary test image allows for continuous monitoring of developer density without needing to interrupt printing, as the measurement target is already prepared and can be measured at any time during operation.
2Productivity
If processing conditions are set once and printing continues for long time, then productivity is maintained, but print image density varies from start to after long printing
Solution Approach 1:
The patent implements a feedback mechanism where the first detection part continuously measures the density of the no-printing developer image, and the correction part uses this information to adjust development voltage and supply voltage. This closed-loop control ensures print image density remains consistent during long printing by automatically compensating for developer depletion or carrier charge variations.
Solution Approach 2:
The patent makes the development voltage and supply voltage dynamic rather than fixed. The correction part continuously adjusts these voltages based on real-time density measurements from the first detection part, allowing the system to adapt to changing conditions during long printing sessions and maintain consistent print quality.
3Manufacturing precision
If development voltage and supply voltage are adjusted to stabilize density, then print image density is stabilized, but system complexity increases
Solution Approach 1:
The patent implements a self-service control system where the correction part automatically adjusts development voltage and supply voltage based on density measurements from the first detection part. The system monitors and corrects its own performance without external intervention, using the no-printing developer image as a built-in reference standard, thereby managing complexity through automation rather than manual calibration.
4Measurement precision
If no-printing developer image is formed on developer carrier, then continuous measurement is enabled, but additional development resources are consumed
Solution Approach 1:
The patent makes the developer carrier multi-functional by using it for both normal printing (printing developer image) and continuous density measurement (no-printing developer image). The same developer carrier and developer material serve dual purposes, eliminating the need for separate test strips or additional measurement materials, thus avoiding extra developer consumption.
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
The apparatus stabilizes print image density during long printing sessions by enabling continuous adjustments of development and supply voltages based on real-time measurements, improving print quality and reducing unnecessary toner consumption.
Implementation Method 1
after a photosensitive drum is charged negatively by a charge roller
Implementation Method 2
an electrostatic latent image is formed when light is irradiated at the negatively charged portion of the photosensitive drum
Implementation Method 3
The electrostatic latent image is developed by a developer supplied from a development roller and a supply roller
Data Source
AI summary
An image forming apparatus includes an exposure part forming an electrostatic latent image on a charge region, a developer carrier developing the electrostatic latent image into two types of development images (printing developer image and no-printing developer image), a supply member supplying developer to the developer carrier, a first detection part detecting a first physical quantity correlating to the density of the no-printing developer image, a setting part performing a setting, based on the first physical quantity, for a development voltage applied to the developer carrier or a supply voltage applied to the supply member, a second detection part detecting a second physical quantity correlating to a number of rotations after the print of the printing developer image starts, a correction part correcting, based on the second physical quantity, the development voltage or the supply voltage set by the setting part, and a power source part applying the development voltage to the developer carrier and applies the supply voltage to the supply member.