Image Forming Apparatus Exposure Timing Control
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Solution Overview
Problem
In image forming apparatuses, the shortening of conveyance paths due to downsizing can cause developer images to be partially transferred outside the sheet, as the exposure operation is terminated when the sheet sensor detects the trailing end of the sheet, leading to misalignment and incomplete transfer.
Innovation Solution
An image forming apparatus with a detector system that includes a first and second detector to monitor the sheet's position, and a controller that determines the exposure completion time and trailing-end detecting time to ensure the developer image is transferred within the sheet by calculating time differences and controlling the exposure unit accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the exposure operation is terminated when the sheet sensor detects the trailing end of the sheet, then the exposure operation timing is simplified, but the developer image may be partially transferred outside the sheet due to shorter conveyance path
Solution Approach 1:
The system performs preliminary actions by detecting the trailing end of the sheet in advance and calculating the required exposure termination time based on the conveyance time period. This allows the exposure operation to be terminated at the correct moment, ensuring the developer image is transferred precisely within the sheet boundaries even with shorter conveyance paths.
Solution Approach 2:
The system uses feedback from the sheet sensor detecting the trailing end position to adjust the exposure termination timing. By continuously monitoring the sheet position and calculating the conveyance time period, the system dynamically determines when to terminate exposure, ensuring accurate transfer positioning while maintaining simple operational control.
2Volume of moving object
If the conveyance path is shortened for downsizing, then the apparatus size is reduced, but the developer image may be transferred outside the sheet due to timing misalignment
Solution Approach 1:
The system performs preliminary calculation of the conveyance time period based on the shortened conveyance path distance and sheet conveyance speed. This pre-calculated timing information is used to determine the exact moment to terminate exposure, ensuring that despite the shorter conveyance path, the developer image transfer remains precisely aligned with the sheet boundaries.
Solution Approach 2:
The system dynamically adjusts the exposure termination timing based on the actual conveyance conditions and the specific shortened path geometry. By making the exposure control adaptive to the specific conveyance time period, the system maintains high transfer position accuracy regardless of the compact apparatus dimensions.
3Device complexity
If a single sheet sensor is used to detect the trailing end, then the device complexity is reduced, but the timing accuracy for exposure termination cannot be ensured
Solution Approach 1:
The detection function is segmented into two independent components: a sheet sensor for detecting the trailing end position and a timer for measuring the conveyance time period. This segmentation allows each component to perform its specific function with high precision, achieving accurate exposure termination timing control without requiring a complex multi-sensor system.
Solution Approach 2:
The timer acts as an intermediary element that bridges the sheet sensor detection and the exposure termination control. By measuring the conveyance time period and using it to calculate the precise termination moment, the timer mediates between the simple sensor input and the precise exposure control output, achieving high timing accuracy with minimal device complexity.
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
Prevents partial transfer of the developer image outside the sheet by accurately determining the exposure completion and trailing-end detection times, ensuring precise alignment and complete transfer of the image onto the sheet.
Implementation Method 1
an exposure unit configured to perform, for an exposure position on a photoconductive body, an exposure operation of exposing the photoconductive body
Implementation Method 2
a development unit configured to develop with development agent the electrostatic latent image formed on the photoconductive body and form a developer image
Implementation Method 3
a transfer unit configured to transfer the developer image from the photoconductive body onto the sheet
Data Source
AI summary
An image forming apparatus is provided that includes a controller configured to perform an acquiring operation of acquiring an exposure completion time point when an exposure operation of exposing a photoconductive body using image data has been completed and a trailing-end detecting time point when a detector has detected a trailing end of a sheet, and a determining operation of determining whether a developer image would be transferred outside the sheet, based on the exposure completion time point and the trailing-end detecting time point acquired in the acquiring operation, a transfer time period required for an arbitrary point on the photoconductive body to move to a transfer position from an exposure position, and a conveyance time period required for a trailing end of the sheet to move to the transfer position since the detector detects the trailing end of the sheet.