Multi-Beam Exposure Control Balances Laser Source Wear
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Solution Overview
Problem
Existing multi-beam image forming apparatuses face issues with light source deterioration and image quality fluctuations due to varying usage rates of multiple laser sources, leading to increased load on the polygon motor and potential color shifts during color image formation.
Innovation Solution
An image forming apparatus with a control section that manages two image forming modes: a first mode using all light sources at a normal speed and a second mode using fewer light sources at a slower speed, where unused light sources emit laser beams outside the image area for stable cleaning and synchronization signal detection, without altering the polygon mirror's rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rotating speed of polygon mirror is changed to lower image formation speed, then the transporting speed of transfer sheet can be reduced for thick paper, but the load onto polygon motor is increased which affects stable long-term operation
Solution Approach 1:
The system dynamically adjusts the number of active light sources based on the image formation speed. At lower speeds (second image forming mode), fewer light sources are activated to reduce the polygon mirror's rotational burden, while at normal speeds (first image forming mode), all light sources are used for maximum productivity. This dynamic configuration allows speed adaptation without compromising motor reliability.
2Speed
If the number of used light sources is decreased to lower image formation speed, then the polygon mirror rotation speed can be maintained, but the difference of light emitting period between used and unused light sources generates uneven deterioration state
Solution Approach 1:
The control section implements periodic switching of light sources between active and standby roles. Each light source alternates between being used for image formation and being unused, ensuring that over time all light sources experience similar cumulative usage and deterioration. This periodic rotation of active light sources prevents any single source from being overused while maintaining the reduced image formation speed.
3Stability of the object's composition
If light sources are switched page by page to equalize deterioration, then the deterioration state can be balanced, but image quality changes page by page due to switching which causes color shift in color image formation
Solution Approach 1:
The system maintains continuous use of the same light source for multiple pages rather than switching per page. The control section determines which light sources to activate based on cumulative usage patterns, ensuring that each light source remains active for a predetermined number of pages. This continuous assignment prevents image quality fluctuations while still achieving long-term deterioration equalization across all light sources.
4Productivity
If all light sources are used at normal speed, then productivity is maximized, but the polygon motor experiences increased load which affects stable operation
Solution Approach 1:
The system segments the light source array into multiple independent groups that can be selectively activated. Instead of using all light sources simultaneously, the control section divides them into subsets based on the required image formation speed. At reduced speeds, only necessary segments are activated, reducing the overall load on the polygon motor while maintaining adequate productivity for the current operational requirements.
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 stabilizes the deterioration state of each light source, preventing image quality degradation and ensuring stable operation by equalizing the usage of multiple laser sources, thus maintaining consistent image quality across pages.
Implementation Method 1
simultaneously conducting multiple lines of exposure by scanning multiple laser beams from multiple light sources onto an image carrier
Data Source
AI summary
An image forming apparatus for simultaneously conducting multiple lines of exposure by scanning multiple laser beams from multiple light sources onto an image carrier in a main scanning direction, including: multiple light sources which are driven to emit laser beams based on image data; and a control section capable of controlling an image formation in two types of image forming modes of a first image forming mode where an image is formed at a first image forming speed by using all the multiple light sources, and a second image forming mode where the image is formed without using at least one of the multiple light sources at a second image forming speed slower than the first image forming speed,wherein the control section controls a light source which is not used in the second image forming mode to emit a laser beam onto outside of an image area.