Image Forming Apparatus Test Pattern Asymmetry
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Solution Overview
Problem
In color image forming apparatuses, positional deviations of images in colors like cyan, yellow, and magenta lead to color shift, making it difficult to form clear images, and existing solutions either increase manufacturing costs or reduce detection stability.
Innovation Solution
The image forming apparatus forms test patterns with first and second line segments slanting in opposite directions, allowing for stable detection without increasing the number of parts, and calculates image positions based on detection timing differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the spot diameter of the detection sensor is narrowed by using a slit plate, then the peak height can be made equal between detection of line segments, but the number of parts increases and manufacturing cost increases
Solution Approach 1:
The test pattern uses line segments L1 and L2 with different orientations (one orthogonal to belt movement, one slanting) to create asymmetric detection characteristics. This asymmetry allows the detection sensor to distinguish between different line segments and achieve equal peak heights without requiring a slit plate, thereby reducing part count while maintaining detection stability
Solution Approach 2:
The invention changes the geometric parameters of the test pattern (line segment orientations and positions) to optimize detection. By carefully selecting the angles and positions of L1 and L2, the system achieves equal peak heights in the detection waveform without needing to modify the sensor hardware with a slit plate
2Measurement precision
If the spot diameter of the detection sensor is narrowed, then the peak height is reduced, but this may improve detection stability
Solution Approach 1:
The invention optimizes the parameters of the test pattern (line segment width, orientation, and position) to maximize the detection signal. By adjusting these parameters, the system achieves strong peak heights in the detection waveform without needing to narrow the sensor spot diameter, thereby maintaining both signal strength and detection stability
3Measurement precision
If test patterns with line segments are used for position detection, then image position can be calculated, but the threshold settable range for detection becomes narrow reducing detection stability
Solution Approach 1:
The asymmetric orientation of line segments L1 and L2 creates distinct detection signatures that broaden the threshold settable range. The different angles at which these segments intersect the sensor spot produce detectable variations in the output waveform, allowing for a wider range of acceptable threshold values while maintaining accurate position detection
Solution Approach 2:
The invention introduces angular orientation as an additional dimension to the test pattern design. By varying the orientation of line segments in addition to their position, the system creates more distinguishable detection signals that broaden the acceptable threshold range and improve detection stability
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 widens the threshold settable range for detection, ensuring stable detection of line segments and accurate calculation of image positions, thereby preventing color shift without increasing manufacturing costs.
Implementation Method 1
a light receiving element that receives reflection light of light which is illuminated onto a reference pattern image
Implementation Method 2
a light receiving element that receives reflection light of light which is illuminated onto a reference pattern image formed on a moving member
Data Source
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AI summary
An image forming apparatus includes a conveying unit that conveys a transferred medium in a first direction, an image forming unit, a controller that controls the image forming unit to form a test pattern including first and second line segments slanting toward directions opposite to each other, wherein the first line segment is offset, in an offset direction, from a second direction orthogonal to the first direction and the second line segment is offset, in a direction opposite to the offset direction, from the second direction, wherein the first and second line segments are formed into a step-like shapes, the first line segment extending by two/four dots in the second direction while extending by one dot in the first direction, and the second line segment extending by two/four dots in the second direction while extending by one dot in a direction opposite to the first direction, and wherein positions where the first and the second line segment extend in the second direction are respectively shifted by one/two dot/s from each other in the second direction, a detection unit that detects passage of at least respective parts of the first and second line segments; and a calculating unit that calculates a position where the image forming unit forms an image based on a time difference between times at which the detection unit detects the passage of the at least part of the first and second line segments.