Position Detector With Dual Line Patterns For Ink Jet Printers
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Solution Overview
Problem
Ink mist attachment on the scale of an encoder in ink jet printers causes light diffraction, leading to erroneous detection and reduced precision in position control, with existing solutions failing to effectively prevent this issue.
Innovation Solution
A position detector configuration featuring a transparent member with alternating first and second line patterns, where only light passing through both patterns is received, shielding diffused or diffracted light and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single line pattern is used on the scale, then the structure is simple, but light diffraction causes erroneous detection
Solution Approach 1:
The scale is divided into two separate line patterns: a first line pattern with first light transmitting sections and first light shielding sections, and a second line pattern with second light transmitting sections and second light shielding sections. This segmentation allows each pattern to independently control light transmission, preventing diffraction errors while maintaining structural clarity.
Solution Approach 2:
The invention introduces a temporal dimension by controlling light transmission in sequence: the first line pattern transmits light during a first period, and the second line pattern transmits light during a second period. This temporal separation prevents simultaneous light paths that would cause diffraction, improving measurement precision without adding spatial complexity.
2Reliability
If ink mist is attached on the scale, then the encoder can detect position, but light diffraction causes erroneous detection
Solution Approach 1:
The invention extracts and separates the light transmission function into two distinct patterns with different transmission characteristics. The first line pattern has wider light transmitting sections that allow light passage, while the second line pattern has narrower sections that block diffused light. This extraction prevents harmful diffraction effects from compromising detection reliability.
Solution Approach 2:
The second line pattern acts as an intermediary filter that receives light from the first line pattern and selectively transmits only the desired light paths while blocking diffused or diffracted light. This intermediary structure prevents harmful light paths from reaching the light receiving element, ensuring reliable detection despite ink mist attachment.
3Measurement precision
If the light transmitting section is narrow, then diffraction is reduced, but light transmission efficiency decreases
Solution Approach 1:
The invention employs periodic action by alternating between two line patterns with different transmission characteristics. During the first period, the first line pattern with wider transmitting sections maximizes light transmission efficiency. During the second period, the second line pattern with narrower sections filters out diffraction errors. This periodic switching achieves both high efficiency and high precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances detection sensitivity by preventing erroneous detection due to diffused or diffracted light, ensuring accurate position detection and precise ink ejection in ink jet printers.
Implementation Method 1
a light emitter, operable to emit light; a light receiver, adapted to receive the light emitted from the light emitter
Implementation Method 2
In a case where the ink mist is attached onto the light transmitting section of the scale, light which passes through the light transmitting section is diffracted and causes a disadvantageous effect
Data Source
AI summary
A light emitter is operable to emit light. A light receiver is adapted to receive the light emitted from the light emitter, and operable to output a signal in accordance with an amount of the received light, thereby detecting a position of an object. At least one transparent member is disposed between the light emitter and the light receiver. A first line pattern is provided with the transparent member so as to oppose the light emitter, and includes first light transmitting sections and first light shielding sections which are alternately arranged in a first direction with a first pitch. A second line pattern is provided with the transparent member so as to oppose the light receiver, and includes second light transmitting sections and second light shielding sections which are alternately arranged in the first direction with a second pitch. Each of the first light transmitting sections is adapted to allow the light emitted from the light emitter to pass through. Each of the first light shielding sections is adapted to shield the light emitted from the light emitter. Each of the second light transmitting sections is adapted to allow light having passed through the transparent member. Each of the second light shielding sections is adapted to shield the light having passed through the transparent member.