Intermediate Transfer Belt Speed Control for Image Quality
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Solution Overview
Problem
Image forming devices experience streaky image disturbances and color shifts due to changes in belt speed when using cardboard as a recording paper, particularly when switching between constant belt speed control and constant motor speed control, leading to positional displacements and uneven toner image transfer.
Innovation Solution
The implementation of a control system that dynamically switches between constant belt speed control and constant motor speed control based on detected paper thickness and print conditions, using a FG signal to maintain stable motor rotation and adjust target speeds to minimize speed variations and positional discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant belt speed control is used to stabilize belt speed, then color shift due to eccentricity is reduced, but streaky image disturbance occurs when feeding thick paper due to excessive speed correction
Solution Approach 1:
The system dynamically switches between constant belt speed control and constant motor speed control based on paper thickness detection. For thin paper, constant belt speed control is used to stabilize speed. For thick paper, constant motor speed control is used to prevent excessive speed correction during feeding, thereby avoiding streaky image disturbance while maintaining acceptable belt speed stability.
Solution Approach 2:
The control parameter is changed from belt speed (constant belt speed control) to motor speed (constant motor speed control) based on the detected paper thickness. This parameter change allows the system to adapt its control strategy: using belt speed stabilization for thin paper and motor speed stabilization for thick paper, thus resolving the contradiction between speed stability and streaky image prevention.
2Object-affected harmful factors
If constant motor speed control is used to prevent streaky image disturbance, then belt speed stability improves for thick paper, but color shift increases due to speed variance from eccentricity
Solution Approach 1:
The system dynamically selects the control mode based on paper thickness. For thick paper where streaky image disturbance is the primary concern, constant motor speed control is applied to prevent excessive speed correction. For thin paper where color shift is more critical, constant belt speed control is used to maintain stable belt speed and reduce color shift from eccentricity.
Solution Approach 2:
The control parameter is switched between motor speed and belt speed depending on paper thickness detection. This allows optimization of each control mode's strengths: motor speed control for preventing streaky images in thick paper, and belt speed control for maintaining color accuracy in thin paper applications.
3Manufacturing precision
If writing position correcting process is executed to reduce color shift, then positional displacement is reduced, but additional processing time is required
Solution Approach 1:
The writing position correcting process is executed in advance before normal printing operations. By performing this calibration process preliminarily, the system establishes accurate writing positions for all subsequent printing tasks, ensuring high positional accuracy without adding time to regular print operations.
Solution Approach 2:
The system performs self-calibration through the writing position correcting process, automatically detecting and correcting its own positional deviations. This self-service approach ensures accurate writing positions without requiring external calibration equipment or manual adjustment, maintaining efficiency while improving precision.
Data Source
AI summary
A main controlling part is configured to choose and execute either a constant belt speed control which controls a driving motor (a driving source for an intermediate transfer belt) to move the intermediate transfer belt at a predetermined target belt speed or a constant motor speed control which rotates the driving motor at a predetermined target rotational speed according to a print command, and then, prior to a first-time print job, after executing a writing position correcting process while moving the intermediate transfer belt under the constant belt speed control, forms a color shift detecting image by switching from the constant belt speed control to the constant motor speed control, measures a difference between amounts of color shift, and executes a speed correcting process for correcting the target rotational speed of the driving motor in the constant motor speed control based on the measurement result.