Image Forming Apparatus Using Line Sensor Tilt and Sheet Masking
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Solution Overview
Problem
Existing image forming apparatuses fail to accurately reflect the tilt of the image pickup portion, such as a line sensor, with respect to the sheet width direction due to misalignment of the tension roller shaft, leading to inaccuracies in image formation.
Innovation Solution
The image forming apparatus includes a configuration where the line sensor is positioned upstream of the image forming portion and acquires shape data of the sheet, masks stick-out areas using this data, and forms an image that reflects the tilt of the line sensor by creating a boundary between masked and unmasked areas, thereby correcting for any misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image pickup portion is positioned upstream to detect sheet shape, then the tilt detection capability is improved, but the image formation accuracy deteriorates due to stick-out areas causing misalignment
Solution Approach 1:
The image pickup portion captures the sheet shape upstream before image formation, allowing the control portion to pre-process the image data by detecting and masking stick-out areas. This preliminary detection and correction enables accurate image formation despite the upstream positioning of the sensor.
Solution Approach 2:
The control portion acts as an intermediary that receives shape data from the image pickup portion, processes it to identify stick-out areas, masks these areas in the image data, and then provides corrected image data to the image forming portion. This intermediary processing resolves the conflict between upstream detection and accurate formation.
2Area of stationary object
If the line sensor captures the entire sheet area including stick-out portions, then complete sheet coverage is achieved, but image placement accuracy deteriorates due to tilt reflection
Solution Approach 1:
Instead of uniformly processing the entire captured image, the control portion applies local quality differentiation by identifying specific stick-out areas and masking only those regions while preserving the rest of the image data. This selective masking maintains image placement accuracy for valid sheet areas while excluding erroneous stick-out portions.
Solution Approach 2:
The control portion performs preliminary analysis of the captured image to identify stick-out areas before image formation, masking these areas in advance. This preliminary action prevents tilt-induced placement errors in the final image output while maintaining complete sheet coverage in the capture phase.
Data Source
AI summary
An image forming apparatus acquires shape data indicating a shape of a specific sheet conveyed along a conveying path, masks, using the acquired shape data, a stick-out area that sticks out from a sheet area included in the shape data out of specific image data whose size in a first direction corresponding to a conveying direction of a sheet is larger than that of the sheet area, and forms, on the specific sheet, an image that shows a boundary between a mask area and a non-mask area opposing each other along the first direction out of the specific image data in which the stick-out area has been masked.