Image forming apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately correcting image density unevenness in both the main scanning and sub-scanning directions due to separate and independent correction targets, leading to reduced accuracy in overall image density uniformity.
Innovation Solution
An image forming apparatus that includes a reading unit to detect image densities at different positions in both the axial and rotation directions of the photosensitive member, and a controller to determine target data based on these readings, thereby suppressing density unevenness by adjusting laser light modulation in both directions simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate and independent correction control is used for main scanning direction and sub-scanning direction image density unevenness, then each direction can be corrected individually, but the correction targets differ between directions causing reduced overall correction accuracy
Solution Approach 1:
The patent merges the separate correction controls for main scanning and sub-scanning directions into a unified correction system. The controller integrates reading results from both directions and determines target data that applies to the entire image forming range, eliminating the discrepancy between directional correction targets and achieving consistent high-accuracy correction across the whole image.
2Ease of operation
If average image density is used as correction target in each direction, then correction can be performed independently in each direction, but the average image densities differ between directions leading to lower correction accuracy
Solution Approach 1:
The patent creates a universal correction target that serves both main scanning and sub-scanning direction corrections. Instead of using separate average image densities for each direction, the system determines a single target data value based on reading results from both directions, making the correction control both simple and universally applicable to the entire image forming range.
3Ease of operation
If minimum image density is used as correction target in each direction, then correction can be performed independently, but the minimum image densities differ between directions causing reduced correction accuracy
Solution Approach 1:
The patent merges the determination of correction targets from both directions into a unified process. Instead of separately determining minimum image densities for main scanning and sub-scanning directions, the controller combines reading results from both directions to determine a single target data value, ensuring consistent correction across the entire image forming range while maintaining operational simplicity.
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 solution achieves high-accuracy correction of image density unevenness in both the main scanning and sub-scanning directions, reducing the difference in image density after correction, and improving overall image quality.
Implementation Method 1
a reading unit configured to read a measurement image formed on the sheet
Implementation Method 2
An amount of laser light is adjusted based on a measurement result of the test image for each region
Implementation Method 3
The image forming apparatus uniformly charges the photosensitive layer of the photosensitive drum, and then irradiates (scans) the photosensitive layer with laser light, to thereby form an electrostatic latent image on the photosensitive layer
Implementation Method 4
heat and pressure are applied to the sheet having the toner image transferred thereon so that the toner image melts to be fixed
Data Source
AI summary
Disclosed is an image forming apparatus for forming an image on a sheet, the image forming apparatus including an image forming unit configured to form an image on a photosensitive member with the photosensitive member rotating, and transfer the image formed on the photosensitive member onto the sheet to form the image on the sheet, a reading unit configured to read a measurement image formed on the sheet by the image forming unit, the measurement image including a first detection image for detecting density at positions different in an axial direction of a rotation axis of the photosensitive member of an image to be formed on the photosensitive member; and a second detection image for detecting density at positions different in a rotation direction of the photosensitive member of an image to be formed on the photosensitive member.