Image Forming Position and Size Adjustment for Sheet Variations
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Solution Overview
Problem
Existing image forming apparatuses struggle to accurately control the image forming position on both sides of a sheet due to variations in sheet size caused by cutting accuracy and fixing processes, leading to potential shifts in image registration.
Innovation Solution
An image forming apparatus that includes an image forming unit, a fixing member, a conveyance roller, a reading device, and a processor to detect the sheet length and adjust the image position and size based on the reading results, ensuring precise alignment on both surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the image forming position is controlled based on nominal sheet size, then the control system is simple, but the image positioning accuracy deteriorates due to sheet size variations
Solution Approach 1:
The patent applies preliminary action by forming an adjustment pattern on the sheet before the main image formation process. This pattern is used to detect actual sheet dimensions and positioning characteristics in advance, allowing the system to compensate for variations before printing the actual image, thereby improving positioning accuracy without significantly increasing overall system complexity
Solution Approach 2:
The patent implements feedback by using a reading device to detect the adjustment pattern formed on the sheet. The detected information about sheet size variations and positioning deviations is fed back to the control system, which then adjusts the image forming position accordingly. This closed-loop feedback mechanism enables accurate image positioning despite sheet size variations
2Productivity
If the sheet size variation is not compensated, then the processing is simple and fast, but the image registration accuracy deteriorates between front and back surfaces
Solution Approach 1:
The system performs preliminary detection of sheet characteristics using the adjustment pattern before main image formation. This preliminary action allows the control system to pre-calculate compensation values for sheet size variations, enabling fast processing of actual images while maintaining high registration accuracy between front and back surfaces
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting image forming parameters (position, size) based on detected sheet characteristics. The control system modifies these parameters in real-time according to the actual sheet dimensions and positioning properties, ensuring accurate image registration without sacrificing processing speed
3Manufacturing precision
If a specific pattern is formed for position adjustment, then the positioning control is improved, but the sheet size variation still affects the accuracy
Solution Approach 1:
The reading device detects the adjustment pattern on the actual sheet, providing feedback about both positioning and sheet size characteristics. This feedback loop allows the system to distinguish between positioning deviations and actual sheet size variations, enabling accurate compensation for both factors independently
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
The apparatus achieves high-accuracy image positioning by compensating for sheet size variations, reducing image registration errors and maintaining consistent image placement on both sides of the sheet.
Implementation Method 1
a fixing member configured to fix the adjustment pattern on the sheet by heating the adjustment pattern on the sheet
Data Source
AI summary
An image forming apparatus includes: an image forming unit configured to form an adjustment pattern on a sheet; a reading device provided further downstream than a fixing member in a conveyance direction, and configured to read the sheet on which the adjustment pattern has been fixed by the fixing member; and a processor configured to: detect a length, in the conveyance direction, of the sheet; and adjust a position, in the conveyance direction, and a size, in the conveyance direction, of an image to be formed on the sheet by the image forming unit, based on a reading result obtained by the reading device reading the sheet and the detected length.