Image Forming Apparatus Test Sheet Edge Detection
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Solution Overview
Problem
Conventional image forming apparatuses struggle to accurately measure the distance between the edge of a sheet and a test pattern, leading to misalignment of images on the front and back sides due to reduced reading accuracy when the paper edge and cover surface have similar colors or when the edge cannot be read.
Innovation Solution
An image forming apparatus that adjusts the printing distance based on readings from a test sheet covered with a colored cover sheet, where the cover sheet is placed outside the reading area on an OC glass with alignment marks, allowing accurate detection of test patterns relative to the OC frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a white cover sheet is used to cover the test sheet, then the reading area is protected, but the edge of the paper cannot be read and reading accuracy deteriorates
Solution Approach 1:
The cover sheet is changed from white to a predetermined color (black or dark color) that creates sufficient contrast with the paper edge. This color change enables the reader to detect the paper edge while the cover sheet remains in place to protect the reading area and maintain alignment.
2Reliability
If the cover sheet color matches the paper edge color, then the cover provides protection, but accurate distance measurement between edge and test pattern becomes impossible
Solution Approach 1:
The cover sheet is specified to have a predetermined color (black or dark color) that differs significantly from the paper edge color. This color differentiation ensures that the reader can accurately detect the paper edge position and measure the distance to the test pattern, thereby improving both edge detection accuracy and measurement precision.
Data Source
AI summary
An image forming apparatus automatically adjusts a printing distance from a sheet edge on the basis of a result obtained by reading, with a reader, a test sheet printed by an image former. The image former prints a solid cover sheet of a predetermined color other than white having a void portion on four sides. The test sheet is placed on OC glass having a first size guide and a second size guide on its periphery, in alignment with the origin of the first size guide and the second size guide. The reader reads the test sheet in a state in which the cover sheet is placed on the test sheet so that the void portion is disposed outside the first size guide and the second size guide.