Composite Measurement Imaging for Printer Density Correction
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Solution Overview
Problem
Image forming apparatuses face challenges in maintaining image quality due to variations in environmental conditions, component durability, and unevenness in photosensitive layers, leading to issues like image density and color unevenness, which existing correction methods increase waste and control time.
Innovation Solution
The apparatus employs a conveyor system, image forming units, a reader, and a controller to form and read measurement images on sheets, using a shading function to correct image density unevenness in the sub-scanning direction by adjusting exposure amounts based on reading results, reducing waste and control time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate measurement images are formed for main scanning direction and sub-scanning direction correction, then image density unevenness can be detected and corrected, but the number of sheets consumed and control time increase
Solution Approach 1:
The patent combines the main scanning direction measurement image and sub-scanning direction measurement image into a single composite measurement image. This allows both types of image density unevenness to be detected simultaneously using one measurement image instead of requiring separate images, thereby reducing the number of sheets consumed and shortening the control time while maintaining detection accuracy for both directions
2Measurement precision
If separate measurement images are formed for main scanning direction and sub-scanning direction correction, then image density unevenness can be detected and corrected, but sheet consumption increases
Solution Approach 1:
The patent merges the main scanning direction measurement image and sub-scanning direction measurement image into a single composite measurement image that contains both types of measurement patterns. This eliminates the need to form and consume multiple separate measurement images, thereby reducing sheet consumption while maintaining the ability to detect both main scanning and sub-scanning direction image density unevenness with high accuracy
3Measurement precision
If measurement images are formed at multiple positions in main scanning direction, then sub-scanning direction image density unevenness can be accurately detected, but the complexity of control increases
Solution Approach 1:
The patent applies local quality by forming measurement patterns at multiple specific positions along the main scanning direction within the single composite measurement image. This allows sub-scanning direction image density unevenness to be detected at multiple locations, improving detection accuracy while the controller processes all these measurements systematically through automated algorithms, managing the increased complexity through structured control logic
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 corrects image density unevenness with high accuracy while minimizing sheet consumption and control time, enhancing image quality and reducing costs.
Implementation Method 1
a photosensitive drum which is a photosensitive member having a drum shape and including a photosensitive layer on its surface
Implementation Method 2
Toner is caused to adhere to the electrostatic latent image by applying a developing bias voltage to the developing sleeve
Implementation Method 3
an exposing device for irradiating the photosensitive drum with laser light
Data Source
AI summary
An image forming apparatus includes a conveyor configured to convey a sheet in a first direction, an image forming unit configured to form an image on the sheet conveyed by the conveyor, the image forming unit including a first image forming unit configured to form an image of a first color, and a second image forming unit configured to form an image of a second color different from the first color, a reader configured to read a measurement image formed on a sheet by the image forming unit, the measurement image including a first measurement image and a second measurement image each including a first pattern image of the first color and a second pattern image of the second color.