Paper Feeding Timing Control in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately determining delays or advances in paper arrival at the resist roller pair and correcting paper feeding start timing, leading to potential productivity issues due to variations in paper position and sheet interval.
Innovation Solution
An image forming apparatus equipped with a resist sensor and an engine control part that measures the time from paper feeding start to paper arrival at the resist sensor, and adjusts the paper feeding start timing based on the measured sheet interval and arrival time to ensure proper alignment and timing of paper at the resist roller pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the paper feeding start timing is advanced based on detected time T to prevent roller slippage and maintain paper line speed, then productivity is improved, but the correction is greatly affected by variations in the position of the leading end of the paper in the paper feeding part, causing inaccurate timing correction and potentially creating a sheet interval that is too small
Solution Approach 1:
The patent implements a feedback mechanism where the actual conveyance time T is measured and used to calculate the timing advance amount (T-T0). This measured feedback is then applied to adjust the paper feeding start timing, creating a closed-loop control system that adapts to actual conveyance conditions rather than relying on fixed predetermined values, thereby improving timing accuracy despite paper position variations
Solution Approach 2:
The patent dynamically changes the timing parameter based on the measured conveyance time T. Instead of using a fixed advance time, the system calculates the timing advance as (T-T0) where T is the actual measured conveyance time. This parameter change approach allows the system to adapt to variations in paper position and conveyance conditions, maintaining accurate timing correction while preventing sheet interval issues
2Reliability
If the paper feeding start timing is advanced to compensate for conveyance delays, then paper arrival timing at the resist roller pair is improved, but variations in paper position cause the correction to be inaccurate, leading to potential sheet interval problems
Solution Approach 1:
The system uses feedback from the measured conveyance time T to determine the timing advance amount. By measuring the actual time T it takes for paper to convey and comparing it to the reference time T0, the system calculates the precise advance needed (T-T0). This feedback-based approach improves paper arrival timing reliability while keeping the control logic relatively simple through direct time measurement and calculation
Solution Approach 2:
The system performs preliminary action by advancing the paper feeding start timing before the paper actually reaches the resist roller pair. The advance amount (T-T0) is calculated based on expected conveyance time, allowing the system to proactively compensate for delays rather than reacting after they occur. This preliminary timing adjustment ensures reliable paper arrival while maintaining straightforward control implementation
Data Source
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AI summary
An image forming apparatus comprises an image-forming part; a paper feeding part; a resist part ; a rotating body ; a detector for detecting the arrival of paper at the resist part; a timer part for measuring a measurement time from when feeding of a second sheet of paper from the paper feeding part is begun to when the detector detects the arrival of the second sheet of paper, and a sheet interval time from when the detector detects the passage of a first sheet of paper immediately preceding the second sheet of paper to when the arrival of the second sheet of paper is detected; and an identifier part for referring to the measurement time , a reference measurement time, the sheet interval time and a reference sheet interval time, and deciding the paper feeding part advancing or delaying the paper feed start timing.