Registration Roller Shift Correction for Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately correcting sheet deflection during registration roller shift due to the influence of the urging force applied by the registration roller, leading to inconsistent shift amounts when shifting the sheet backward or forward, resulting in inaccurate image formation.
Innovation Solution
An image forming apparatus with a detecting unit to measure sheet deflection and a control unit that applies different shift corrections based on the direction of deflection, using correction equations or tables to adjust for the urging force, ensuring accurate alignment regardless of the shift direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the registration roller is biased by a spring to shift stably in one direction, then the registration roller can maintain stable positioning, but the shift amount of the sheet becomes differently measured when shifting backward or forward
Solution Approach 1:
The patent applies different correction values based on the shift direction (backward or forward) to compensate for the spring bias. By changing the correction parameter according to the direction of movement, the system achieves accurate sheet positioning despite the unstable force field created by the spring bias.
Solution Approach 2:
The patent uses a line sensor to detect the actual position of the sheet after registration roller shift, then feeds back this information to calculate and apply appropriate correction values. This closed-loop feedback mechanism compensates for the measurement errors caused by spring bias in different directions.
2Manufacturing precision
If the registration roller is shifted beyond the home position to correct sheet deflection, then the sheet can be realigned to the reference position, but the urging force causes inconsistent shift amounts in different directions
Solution Approach 1:
The patent stores multiple correction values in a correction value setting unit, each corresponding to different shift directions and magnitudes. By selecting and applying the appropriate correction value based on the detected deflection direction, the system ensures consistent and reliable sheet alignment regardless of whether the shift is forward or backward.
Solution Approach 2:
The patent divides the correction process into separate cases for backward shift and forward shift, with distinct correction values for each direction. This segmentation allows the system to handle each direction's unique characteristics (influenced by spring bias) independently, improving overall reliability.
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 enables precise registration roller shift corrections, ensuring the sheet is aligned correctly, thereby improving the accuracy of image formation by accounting for the urging force's impact on shift amounts, regardless of the direction.
Implementation Method 1
a registration roller which is biased to one side of the sheet width direction by a predetermined urging force to shift toward the sheet width direction
Data Source
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AI summary
An image forming apparatus acquires an amount of deflection of the transporting sheet from a reference position thereof and calculates a required shift amount of the sheet. It determines whether or not the sheet is shifted frontward. If so, the image forming apparatus acquires a second specified shift value which is set by taking an urging force into consideration using a second correction equation. Alternatively, if the sheet is shifted backward, the image forming apparatus acquires a first specified shift value which is set by taking the urging force into consideration using a first correction equation. The image forming apparatus performs a registration roller shift correction based on the acquired first or second specified shift value.