Optical Detection System for Inkjet Gap Adjustment
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Solution Overview
Problem
Conventional inkjet recording apparatuses face challenges in accurately detecting the operation amount of detection target devices, which is crucial for maintaining an appropriate gap between the conveyed sheet and the inkjet head, especially when handling sheets of varying thicknesses.
Innovation Solution
A detection system is implemented, featuring a first rotating member that rotates in increments corresponding to 1/N of a full rotation, driving a second rotating member to output a monotonic increase or decrease in value, allowing for precise detection of the operation amount and adjustment of the gap adjustment device's height in accordance with sheet thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional detection device is used to detect the operation amount of the gap adjustment device, then the detection system is simple, but the detection precision is insufficient for accurate gap control with varying sheet thicknesses
Solution Approach 1:
The patent replaces conventional mechanical detection methods with an optical detection system. A light source emits light that passes through a light shield attached to the rotating member, and a photodetector detects the light intensity variations. This optical substitution provides higher detection precision while maintaining reasonable system complexity through the use of standard optical components.
Solution Approach 2:
The detection system utilizes periodic action by attaching a light shield with periodic transparent and opaque patterns to the rotating member. As the rotating member rotates, these patterns periodically interrupt the light path, creating periodic signal variations that correspond to the rotation angle. This periodic modulation enables precise detection of the operation amount through signal processing.
2Measurement precision
If the gap adjustment device rotates in small increments (1/N rotation), then the detection resolution improves, but the output signal becomes non-monotonic and harder to process
Solution Approach 1:
The patent introduces a light shield as an intermediary element between the rotating member and the photodetector. The light shield converts the mechanical rotation into optical signal modulation through its periodic transparent and opaque patterns. This intermediary transformation creates a monotonic relationship between rotation angle and detected light intensity, simplifying signal processing while maintaining high detection resolution.
Solution Approach 2:
The system changes the parameter being measured from direct mechanical position to optical intensity. By measuring light intensity variations instead of directly measuring mechanical position, the system achieves monotonic signal output that is easier to process. The photodetector converts optical parameter changes into electrical signals that linearly represent the rotation angle.
Data Source
AI summary
A detection system includes a detection target device and a detection device. The detection target device includes a first rotating member rotatable about a first axis, and repeats an operation corresponding to a rotation angle of the first rotating member every time the first rotating member makes a 1/N rotation, N being an integer of 2 or greater. The detection device includes a second rotating member rotatable about a second axis due to a driving force transmitted from the first rotating member, and an output value of the detection device repeats monotonic increase or monotonic decrease in accordance with a rotation angle of the second rotating member every time the second rotating member makes 1 rotation. Every time the first rotating member makes a 1/N rotation, the second rotating member makes 1 rotation.