Image Forming Apparatus Light Source Timing Control
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Solution Overview
Problem
Conventional image forming apparatuses with multiple photosensitive members scanned by a single polygonal mirror face delays in image formation due to the need for calculating pseudo BD signals, leading to longer first print out times.
Innovation Solution
The apparatus employs first and second photosensitive members with corresponding light sources and a rotatable polygonal mirror, using signal output means to generate pseudo BD signals for synchronizing light emission timing, allowing latent image formation to start before completing correction value calculations, thereby reducing the first print out time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pseudo BD signal correction calculations are completed before starting image formation, then image writing timing synchronization is improved, but first print out time increases
Solution Approach 1:
The system performs preliminary actions by starting the rotation of the polygonal mirror and preparing the imaging system before the pseudo BD signal correction calculations are completed. The first photosensitive member begins receiving light and forming images while the correction values are being calculated, rather than waiting for complete synchronization setup.
Solution Approach 2:
The system maintains continuous useful action by ensuring that the polygonal mirror rotates continuously and the first photosensitive member continuously receives light and forms images throughout the calculation period. The image formation process does not interrupt or pause while correction calculations are performed, allowing overlapping of calculation and imaging operations.
2Device complexity
If multiple photosensitive members are scanned by a single polygonal mirror with pseudo BD signal generation, then device complexity is reduced, but timing synchronization becomes more difficult
Solution Approach 1:
The single polygonal mirror serves multiple functions by scanning multiple photosensitive members (first and second photosensitive members) with different light sources. The system uses one BD sensor to generate both direct BD signals and pseudo BD signals that serve as timing references for multiple imaging paths, reducing the need for separate sensors while maintaining synchronization capability.
Solution Approach 2:
The pseudo BD signal acts as an intermediary timing reference that mediates between the single BD sensor output and the multiple photosensitive members. The correction value calculation process transforms the single BD signal into multiple synchronized timing signals that coordinate the different imaging paths without requiring direct individual sensing for each member.
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 enables faster image formation by starting the yellow image formation before completing pseudo BD signal correction calculations, resulting in a shorter first print out time in full-color mode.
Implementation Method 1
a rotatable polygonal mirror for deflecting the light, emitted from the first light source, toward the first photosensitive member and for deflecting the light, emitted from the second light source, toward the second photosensitive member
Implementation Method 2
first signal output means for outputting a first signal by detecting, in a predetermined position, the light emitted from the first light source and deflected by the rotatable polygonal mirror
Data Source
AI summary
An image forming apparatus includes first and second photosensitive members; first and second light sources; a rotatable polygonal mirror; a first signal output portion; and a second signal output portion. The first light source emits the light at timing on the basis of the first signal, and the second light source emits the light at timing on the basis of the second signal so that latent images are formed on the first and second photosensitive members, respectively, and then are developed with developers to form developer images on the first and second photosensitive members, respectively, and then an image is formed by superposing the developer images. Before output of a second signal from the second signal output portion is started, the first light source emits the light on the basis of a first signal to start formation of the latent image on the first photosensitive member.