Position Detection Correction for Thermal Drift in Image Forming
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Solution Overview
Problem
Existing position detection systems in image forming apparatuses face errors due to changes in the mounting angle and expansion/contraction of reading devices caused by heat, leading to inaccurate correction of conveyance and processing positions.
Innovation Solution
A position detecting device comprising a first position detector, a second position detector, and a controller that uses marks on a position reference member to accurately correct the mounting angle of the reading device, accounting for expansion and contraction, by calculating and applying correction values to the detection results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reading device is used to detect position information, then position detection capability is provided, but expansion and contraction of the reading device caused by generated heat lead to errors in position detection results
Solution Approach 1:
A position reference member with a mark is introduced as an intermediary standard. The reading device reads this reference mark to detect its own position changes caused by thermal expansion/contraction. This intermediary reference allows the system to measure and correct the reading device's positional drift, thereby maintaining detection accuracy despite temperature-induced dimensional changes.
Solution Approach 2:
The system implements a feedback mechanism where the reading device continuously reads the position reference member to detect its own positional changes. The detected position information of the reference mark is fed back to calculate correction values, which are then applied to subsequent position measurements. This closed-loop feedback compensates for thermal expansion/contraction effects in real-time.
2Measurement precision
If correction values are calculated based on reading device position changes, then position accuracy is improved, but mounting angle correction errors occur due to sensor state changes
Solution Approach 1:
The position reference member is pre-configured with a mark at a known position relationship relative to the reading device's predetermined position (e.g., pixel position). This preliminary setup establishes a reference baseline before operation. When thermal expansion occurs, the system compares the actual read position against this pre-established reference to calculate accurate correction values, separating thermal effects from mounting angle errors.
3Productivity
If the reading device operates continuously, then productivity is maintained, but heat generation causes expansion and contraction leading to detection errors
Solution Approach 1:
The system maintains continuous operation by implementing continuous correction. The reading device continuously reads the position reference member during operation, and correction values are continuously calculated and applied based on detected positional changes. This continuous feedback mechanism ensures that productivity is maintained while compensating for thermal effects that occur during sustained operation.
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 solution effectively reduces errors in position detection by accurately correcting the mounting angle and expansion/contraction effects, ensuring precise detection of object positions and image patterns, thereby improving the accuracy of image formation processes.
Implementation Method 1
an error in a position detection result generated by expansion and contraction of the reading device caused by generated heat
Data Source
Figure 1
Figure 2(a)~2(b)
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AI summary
A position detecting device (200) includes a first position detector (111), a second position detector (112), and a controller (113). The first position detector (111) controls a reading device (201) to detect, as a first detection result, an outer shape of a processing subject and a position of an image pattern on the processing subject. The second position detector (112) controls the reading device (201) to detect, as a second detection result, a mark (M) arranged on a position reference member (202), the mark (M) corresponding to a predetermined position in the reading device (201). The controller (113) detects a first correction value of the reading device (201) and a second correction value of the reading device (201) corrected by the first correction value on basis of the second detection result and reflects the values to the first detection result to correct a processing position in the processing subject.