Image Forming Apparatus Mark Position Detection
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately calculating the position of marks on a sheet of paper due to varying conveyance speeds, which affects the correction of printed images.
Innovation Solution
An image forming apparatus equipped with a conveyer, image reader, detector, processor, and memory that calculates the position of marks based on detected values from the detector, using encoders and contact image sensors to accurately determine mark positions despite conveyance speed variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conveyance speed of the recording medium is varied, then the productivity of the image forming apparatus is improved, but the measurement precision of mark position deteriorates
Solution Approach 1:
The system uses a detector to continuously monitor the actual conveyance amount of the recording medium and feeds this information back to the processor. The processor then calculates the mark position based on this feedback data, allowing accurate position determination even when conveyance speed varies. This closed-loop feedback mechanism resolves the contradiction by making the measurement system adaptive to speed changes.
Solution Approach 2:
The invention replaces mechanical position measurement methods with an optical detection system (image reader) combined with computational calculation. Instead of relying on mechanical encoders or fixed-position sensors that are sensitive to conveyance speed variations, the system uses optical reading of marks and calculates positions based on detected values, thereby substituting a speed-sensitive mechanical system with a speed-insensitive optical-computational system.
2Productivity
If the conveyance speed changes during reading, then the productivity is improved, but the manufacturing precision of image alignment deteriorates
Solution Approach 1:
The system continuously monitors the actual conveyance amount during the reading process and uses this feedback information to calculate corrected mark positions. This allows the system to maintain manufacturing precision by compensating for speed variations in real-time, resolving the contradiction between high-speed operation and alignment accuracy.
Solution Approach 2:
The invention changes the approach from fixed-parameter mechanical measurement to variable-parameter optical detection and calculation. The system adapts its measurement parameters based on actual conveyance conditions, calculating mark positions using detected values that reflect the current conveyance state, thereby maintaining precision across varying speeds.
Data Source
AI summary
An image forming apparatus includes a conveyer configured to convey a recording medium on which a mark is formed; an image reader configured to read an image formed on the recording medium while the recording medium is being conveyed; a detector configured to detected a value corresponding to a conveyance amount of the recording medium conveyed by the conveyer and output the detected value; and a processor and a memory that stores program instructions causing the processor to calculate a position of the mark on the recording medium with respect to a conveyance direction of the recording medium based on respective detected values output from the detector when an edge of the recording medium and the mark are read by the image reader.