Multi-Beam Laser Pitch Identification for Image Quality Control
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Solution Overview
Problem
The use of multi-beam laser elements with different light emitting point pitches in image forming apparatuses leads to variations in pivotal moving amounts, affecting illuminance distribution and writing timing corrections, resulting in image defects such as uneven density and moire.
Innovation Solution
An image forming apparatus is designed with a control portion that identifies the light emitting point pitch of the multi-beam laser elements, allowing for appropriate corrections in illuminance distribution and writing timings to ensure uniform image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-beam laser elements from different manufacturers are used to increase productivity, then the number of output sheets per minute increases, but the light emitting point pitch varies causing image defects
Solution Approach 1:
The patent changes the parameter of light emitting point pitch information by reading it from a storage unit and using it to adjust pivotal moving amounts and illuminance distribution correction quantities. This allows the system to adapt to different laser elements while maintaining image quality.
Solution Approach 2:
The system implements feedback by reading the light emitting point pitch information, comparing it with standard values, and automatically adjusting the pivotal moving amounts and correction quantities accordingly. This closed-loop control ensures consistent image quality across different laser manufacturers.
2Adaptability or versatility
If the light emitting point pitch varies among laser elements, then adaptability to different manufacturers is improved, but illuminance distribution uniformity deteriorates
Solution Approach 1:
The system adjusts the illuminance distribution correction quantity based on the read light emitting point pitch information. By dynamically changing this correction parameter, the system maintains uniform illuminance distribution across different laser elements from various manufacturers.
Solution Approach 2:
The patent implements dynamic adjustment of pivotal moving amounts and correction quantities based on the actual light emitting point pitch. This dynamic adaptation allows the system to handle different laser manufacturers while maintaining consistent image quality.
3Measurement precision
If pivotal moving amounts are adjusted to correct image position, then writing timing accuracy is improved, but illuminance distribution changes causing density variations
Solution Approach 1:
The system independently adjusts two parameters: pivotal moving amounts for writing timing correction and illuminance distribution correction quantities for density uniformity. By decoupling these adjustments and controlling them separately based on light emitting point pitch information, the system achieves both accurate timing and uniform illuminance.
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 effectively reduces the occurrence of image defects by enabling precise corrections based on the identified light emitting point pitch, ensuring consistent and high-quality image output even with different laser elements.
Implementation Method 1
a semiconductor laser element which emits laser lights corresponding to an image signal
Implementation Method 2
a light deflector such as a rotational polygon mirror which deflects the laser lights
Implementation Method 3
an imaging optical element having fθ characteristics, etc. And the scanning optical device forms an image of the laser lights in a spot shape on a photosensitive drum
Implementation Method 4
Writing timings of the laser lights on the photosensitive drum are determined by an incidence timing of the laser lights into a horizontal synchronizing sensor
Data Source
AI summary
An image forming apparatus incudes a photosensitive member, a scanning optical unit and a control portion. The scanning optical unit is provided with a light source including a plurality of light emitting points and emitting laser lights form the plurality of light emitting points, respectively and a deflector deflecting each of the laser lights emitted from the plurality of light emitting points into a scanning direction. The scanning optical unit scans the photosensitive member with the plurality of laser lights deflected by the deflector and forms an electrostatic latent image on the photosensitive member. The control portion controls the scanning optical unit. Based on information regarding a light emitting point pitch as an interval between the plurality of light emitting points, the control portion identifies the light emitting point pitch.