Inkjet Head Position Correction Using Edge Sensor Feedback
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Solution Overview
Problem
Conventional image forming apparatuses, such as line-type inkjet printers, face inaccuracies in correcting head unit positions due to errors in edge position detection by edge sensors, leading to potential printing failures from ink droplet discharge deviations.
Innovation Solution
An image forming apparatus comprising a conveyor, multiple head units, edge sensors, an actuator, and a controller, where edge sensors detect edge positions and generate reference values to correct head unit positions, canceling out errors in edge position readings to ensure accurate alignment and prevent color deviations during printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If edge sensors are used to detect edge positions for head unit position correction, then head unit positioning is improved, but measurement errors from assembly errors and sensor individual differences cause inaccurate correction
Solution Approach 1:
The system uses multiple edge sensors to detect edge positions and implements a feedback mechanism where the controller calculates relative positional relations between edge positions at different head unit locations. This feedback loop enables continuous monitoring and correction of positioning errors, compensating for individual sensor inaccuracies through comparative analysis.
Solution Approach 2:
The controller acts as an intermediary that processes edge position data from multiple sensors and calculates relative positional relations. By using the relative positional relation between edge positions at different locations as an intermediate calculation step, the system can correct head unit positions without being directly affected by absolute measurement errors from individual sensors.
2Manufacturing precision
If head unit positions are corrected based on relative positional relations from edge sensors, then printing accuracy is improved, but sensor errors propagate to cause remaining deviations in ink droplet discharge points
Solution Approach 1:
The system implements a feedback mechanism where the controller continuously monitors edge positions using multiple sensors and adjusts head unit positions based on calculated relative positional relations. This feedback loop enables real-time compensation for positioning errors, ensuring that ink droplets are discharged at accurate locations despite initial sensor measurement errors.
Solution Approach 2:
The controller serves as an intermediary that processes edge position data and calculates relative positional relations between different head unit locations. By using this intermediate calculation approach, the system can correct head unit positions while filtering out absolute measurement errors, thereby improving ink droplet discharge accuracy.
3Measurement precision
If multiple edge sensors are deployed across head units, then positioning coverage is improved, but device complexity increases
Solution Approach 1:
The multiple edge sensors serve multiple functions: they detect edge positions for correction, provide data for calculating relative positional relations, and enable error compensation through comparative analysis. This multi-functionality justifies the increased sensor count by maximizing the utility of each sensor within the system.
Solution Approach 2:
The system uses the network of edge sensors as part of a feedback mechanism where data from multiple sensors is processed to calculate relative positional relations and correct head unit positions. The feedback approach transforms the complexity of multiple sensors into a advantage, using comparative analysis to cancel out individual sensor errors and improve overall measurement reliability.
Data Source
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Figure 5A~5B
AI summary
An image forming apparatus includes a conveyor (201), head units (310a, 310b, 310c, 310d), edge sensors (312a, 312b, 312c, 312d), an actuator (311b, 311c, 311d), a memory (416), and a controller (417). The edge sensors (312a, 312b, 312c, 312d) are arranged in correspondence with at least two sensor-corresponding head units of the head units, to detect edge positions of the recording medium in a direction perpendicular to a conveyance direction of the recording medium. The actuator (311b, 311c, 311d) moves at least one actuator-driven head unit of the sensor-corresponding head units in the direction perpendicular to the conveyance direction. The memory (416) stores reference values generated in advance based on data on the edge positions read by the edge sensors. The controller (417) controls the actuator according to the edge positions read by the edge sensors and the reference values to correct a position of the actuator-driven head unit.