Paper Conveyance Line Shifting for Accurate Edge Detection
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Solution Overview
Problem
Existing image forming apparatuses face issues with erroneous detection of recording medium edges due to paper dust deposition, leading to inaccurate correction of skew and shift, which can cause operational errors and stoppages.
Innovation Solution
A conveyance device with a conveyor, shifter, detector, and controller that shifts the recording medium to a new conveyance line orthogonal to the original line, positioning the edge outside paper dust to ensure accurate detection and correction of skew and shift, and includes a cleaning notification system to maintain path cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the recording medium is continuously conveyed along the same conveyance line, then the conveyance process is simple and efficient, but paper dust accumulates on the detector causing erroneous edge detection
Solution Approach 1:
The patent implements dynamic switching between a first conveyance line and a second conveyance line. The controller alternates the recording medium between these two lines based on detection results, preventing paper dust accumulation on the detector by periodically changing the detection position. This dynamic approach maintains both conveyance efficiency and detection accuracy.
Solution Approach 2:
The patent introduces a width-direction offset between the first conveyance line and the second conveyance line. By shifting the conveyance path in the width direction (orthogonal to the conveyance direction), the detector can detect edges at different positions, preventing paper dust from continuously affecting the same detection point. This dimensional change resolves the contradiction between continuous conveyance and dust prevention.
2Measurement precision
If the recording medium is shifted to a different conveyance line to avoid paper dust, then edge detection accuracy is maintained, but the conveyance system becomes more complex
Solution Approach 1:
The system uses dynamic control to switch between two conveyance lines based on real-time detection needs. The controller activates the shifter only when necessary to move the recording medium to the alternate line, maintaining detection precision while avoiding continuous complexity. The dynamic switching is triggered by detection results, ensuring precision without unnecessary system complexity.
Solution Approach 2:
The patent implements periodic switching between the first and second conveyance lines. After detecting an edge on one line, the system periodically shifts to the other line for subsequent detections. This periodic action maintains measurement precision by preventing paper dust accumulation, while the regular pattern keeps the control logic manageable and the system complexity controlled.
3Productivity
If the edge detection is performed at the same position continuously, then the detection process is simple and fast, but paper dust causes erroneous detection leading to operational stoppages
Solution Approach 1:
The system performs preliminary detection on the first conveyance line, and when paper dust is detected, it proactively shifts to the second conveyance line before erroneous detection occurs. This preliminary action maintains detection speed by quickly identifying dust presence and switching lines in advance, preventing operational stoppages and ensuring continuous reliable operation.
Solution Approach 2:
The detector provides feedback about edge detection results to the controller. When detection results indicate paper dust interference (erroneous readings), the controller uses this feedback to switch to the second conveyance line. This feedback mechanism maintains both detection speed and operational continuity by rapidly responding to dust conditions and adjusting the conveyance path accordingly.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A conveyance device includes a conveyer (11, 19) to convey a recording medium in a conveyance direction; a shifter (11) to shift the recording medium, while conveying the recording medium, from a first conveyance line to a second conveyance line in a width direction; a detector (12a, 12b, 12c, 12d) facing a conveyance path to detect an edge of the recording medium to detect at least one of a skew and a shift of the recording medium, and a controller (511) that controls the shifter (11) to correct the at least one of the skew and the shift, shift the recording medium from the first conveyance line to the second conveyance line, and convey the recording medium along the second conveyance line while an edge of the recording medium is disposed outside an edge of the recording medium conveyed along the first conveyance line in the width direction.