Inkjet Ejection Timing Correction for Belt Speed Fluctuations
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Solution Overview
Problem
The fluctuation in rotation speed of the conveyance belt in image forming apparatuses, caused by factors like motor unevenness and load variations, leads to inconsistent sheet conveyance speed, resulting in image distortion due to incorrect inkjet ejection intervals.
Innovation Solution
A control method that utilizes a rotary encoder to measure pulse intervals, accumulates and records data, and derives reference values for each rotational phase, allowing for real-time correction of inkjet ejection intervals based on measured values, thereby maintaining consistent image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conveyance belt rotation speed is measured and corrected using a single reference value, then the control method is simple, but the correction accuracy is insufficient due to rotation unevenness at different phases
Solution Approach 1:
The patent divides the conveyance belt rotation into multiple phases (e.g., 0° to 360° divided into several segments) and measures the pulse interval for each phase separately. This segmentation allows the system to capture rotation unevenness at different phases and apply phase-specific correction values, significantly improving measurement accuracy without requiring overly complex equipment
Solution Approach 2:
The patent performs preliminary measurement and accumulation of pulse interval data for multiple phases before actual inkjet ejection. Reference values for each phase are pre-calculated and stored, allowing the system to quickly apply corrections during operation without real-time complex calculations, thus improving accuracy while maintaining operational simplicity
2Adaptability or versatility
If the conveyance belt rotation speed fluctuates due to motor unevenness and load variations, then the system adapts to real-world conditions, but image distortion occurs due to incorrect inkjet ejection intervals
Solution Approach 1:
The patent implements a feedback mechanism where the rotary encoder continuously monitors the actual rotation speed of the conveyance belt, and the system adjusts the inkjet ejection timing based on measured deviations from the reference speed. The pulse intervals are measured, compared against reference values, and correction values are applied to maintain accurate ejection timing despite speed fluctuations
Solution Approach 2:
The patent dynamically changes the inkjet ejection timing parameters based on measured conveyance speed variations. By calculating correction values from pulse interval measurements and adjusting ejection intervals accordingly, the system adapts to changing rotation conditions while maintaining image formation precision
Data Source
AI summary
A processor measures a pulse interval for a plurality of rotational phases of a rotary encoder, respectively. Each time the pulse interval is measured, the processor accumulates a measured value, which is the pulse interval or a moving average of the pulse interval of time-series data in association with corresponding one of the plurality of rotational phases, and records the measured value in a storage device. The processor derives a plurality of reference values corresponding to the plurality of rotational phases. Each time the measured value is newly obtained, the processor derives a correction value of a time interval of ink ejection of the inkjet recording apparatus in accordance with a difference between the measured value that is newly obtained and a corresponding reference value. The corresponding reference value corresponds to one of the rotational phases which corresponds to the measured value that is newly obtained.