Image Forming Apparatus Multi-Focal Spot Scanning
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Solution Overview
Problem
Conventional image forming apparatuses using a multi-beam writing method suffer from 'reciprocatory failure,' leading to uneven image density and degraded quality, and existing solutions to address this issue are costly and do not meet future demands for higher image quality.
Innovation Solution
An image forming apparatus with a light source, deflector, and scanning optical system that focuses a light beam onto an image carrying member, where one pixel is formed by multiple light spots with different focal positions in the sub-scanning direction, and at least one light spot has a unique scan timing, enabling improved image formation without density unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple light beams are simultaneously used for scanning to achieve high-speed and high-resolution image formation, then productivity is improved, but manufacturing precision deteriorates due to reciprocatory failure causing density unevenness
Solution Approach 1:
The patent applies periodic action by scanning light beams in multiple passes over the image carrying member. Instead of forming all pixels simultaneously in a single pass, the system performs repeated scanning cycles where different light beams scan at different times. This periodic scanning approach eliminates reciprocatory failure while maintaining high-speed image formation capability, as the same pixel location is exposed multiple times by different beams at different moments rather than all at once.
2Manufacturing precision
If existing measures are taken to reduce density unevenness, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent reduces device complexity by using a simple periodic scanning approach where the same light beam or different light beams scan the image carrying member multiple times in sequence. This eliminates the need for complex additional hardware or sophisticated control systems that would be required by other methods, achieving density uniformity improvement through straightforward temporal separation of scanning operations.
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 reduces density unevenness and enhances image quality without increasing costs, achieving higher resolution and stability in image formation by carefully controlling the focal positions and scan timings of light spots.
Implementation Method 1
a light source that includes a plurality of light emitting units and outputs a light beam
Implementation Method 2
a scanning optical system that focuses the light beam deflected by the deflector
Data Source
AI summary
A deflector deflects a light beam from a light source. A scanning optical system focuses the light beam deflected by the deflector. An image carrying member is located at a focal position of the light beam and includes a surface that is scanned in a main scanning direction with the light beam focused by the scanning optical system. One pixel of an image is formed by a plurality of light spots having different focal positions in at least a sub-scanning direction. At least one light spot from among the light spots is formed on the surface of the image carrying member at a scan timing different from those of rest of the light spots.