Movable Density Sensor for Shading Correction in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in correcting shading characteristics in the main scanning direction, leading to uneven image density, which can result in degraded image quality, and require multiple density sensors that increase production costs and processing load.
Innovation Solution
An image forming apparatus with a movable density sensor that detects density while moving in the main scanning direction, allowing for continuous density measurement and correction of the optical scanner's driving signal based on positional data, thereby reducing unevenness in density without the need for multiple sensors or output adjusters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple density sensors are used to detect unevenness in density across the main scanning direction, then measurement precision is improved, but device complexity and production costs increase
Solution Approach 1:
The patent applies the dynamics principle by making the density sensor movable rather than fixed. The sensor is positioned on a movable support that can move in the main scanning direction, allowing a single sensor to sequentially measure density at multiple positions. This dynamic positioning replaces the need for multiple fixed sensors, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent introduces temporal dimension to the measurement process. Instead of having multiple sensors simultaneously measure different positions (spatial dimension), a single sensor measures different positions at different times by moving along the main scanning direction. This transformation from spatial parallel measurement to temporal sequential measurement reduces the number of sensors required while maintaining comprehensive coverage.
2Manufacturing precision
If multiple density sensors are deployed to correct shading characteristics, then image quality is improved, but production costs increase
Solution Approach 1:
The movable density sensor enables comprehensive shading correction across the main scanning direction using a single sensor. By moving the sensor to different positions and collecting density data, the system achieves the same shading correction capability that would require multiple fixed sensors, thereby reducing production costs while maintaining image quality.
Solution Approach 2:
The single movable density sensor performs multiple measurement functions that would otherwise require multiple dedicated sensors. The sensor can measure density at various positions along the main scanning direction, enabling comprehensive shading correction for the entire image width, thus providing multi-functionality with a single component.
3Device complexity
If a fixed density sensor is used, then device complexity is reduced, but measurement precision across the main scanning direction is insufficient
Solution Approach 1:
The patent transforms the fixed sensor configuration into a dynamic one. The density sensor is mounted on a movable support that can position the sensor at different locations in the main scanning direction. This dynamic positioning capability enables the sensor to detect density variations across the entire scanning width, achieving comprehensive measurement precision without requiring multiple sensors.
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 effectively reduces unevenness in image density in the main scanning direction, enhances shading correction resolution, and lowers production costs by eliminating the need for multiple sensors and output adjusters, while maintaining high image quality.
Implementation Method 1
An optical writer irradiates the surface of the photoconductor thus charged with a light beam to form an electrostatic latent image on the surface of the photoconductor according to the image data
Implementation Method 2
The movable first density sensor detects unevenness in density of the toner image in the main scanning direction
Data Source
AI summary
An image forming apparatus includes a photoconductor, an optical scanner, a development device, a movable density sensor, a density sensor driver, and a processor. The optical scanner includes a light source to emit light, and irradiates a surface of the photoconductor in a main scanning direction with the light to form a latent image on the surface of the photoconductor. The development device develops the latent image into a toner image. The density sensor detects unevenness in density of the toner image in the main scanning direction. The density sensor driver moves the density sensor in the main scanning direction. The processor corrects a driving signal for the light source according to image data to reduce the unevenness in density in the main scanning direction, according to positional data of the density sensor in the main scanning direction and an output value of the density sensor.