JPH01448A - Media preservation state measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the storage state of a medium such as a fluid, and more particularly to an apparatus for measuring the storage state of a liquid containing a pigment coating for an organophotoreceptor.

Figure 5 is a diagram for explaining an example of a conventional physical property value measuring device.In the figure, 1 is a light emitting element, 2 is an optical waveguide, 3 is a light receiving element, 4 is a medium to be measured, Reference numeral 5 denotes a constant current source, and as is well known, the light emitted from the light emitting cord 1 such as an LED that is driven by the constant current source 5 or the like to generate light with a constant light intensity is transmitted through the optical waveguide 2.
The light beam is introduced into the optical waveguide 2, propagates through the optical waveguide 2 while being reflected several times, and enters a light receiving element 3 such as a photodiode. At this time, when the refractive index of the liquid 4 changes, the reflection angle and refraction angle change according to Snell's law, and the degree of light scattering of the liquid changes. That is, as the refractive index of the liquid 4 changes, the intensity of light reaching the light receiving element 3 changes. Also, when light is reflected, evanescent waves are generated along the optical waveguide surface.
If a solute that absorbs at this wavelength of light is present in the liquid 4, this evanescent wave is absorbed by the solute. That is, if the solute concentration in the liquid changes, the light intensity reaching the light receiving element 3 changes. In this way, the propagating light intensity changes due to a change in the refractive index of the liquid or a change in the absorbance of the solute, and the state of the liquid can be measured.

However, if the storage container for the liquid to be measured has a good seal, there will be no change in the component ratio in the liquid, and the refractive index of the component will change due to chemical changes in the component in the liquid due to oxidation, heat, etc. The change is small, and Figure 2 (a).

As shown in (b), when the absorbance for the set wavelength shown by the two-dot chain line hardly changes and the refractive index change of the entire liquid is small, that is, when the state of the liquid changes, the refractive index change and the absorbance change for the set light source If there is no change or the degree of change is small, it is not possible to detect a change in the state of the liquid using the above method. Additionally, if the liquid is flammable, other electrical methods of measuring the condition may pose a fire risk.

Purpose The present invention was made in view of the above-mentioned circumstances.
The purpose of this invention is to provide an apparatus that can increase detection sensitivity and maintain measurement accuracy for media whose refractive index changes little when quality deteriorates during quality inspection of storage conditions of media such as liquids.

In order to achieve the above object, the present invention combines a light-emitting element and a light-receiving element with an optical waveguide at least partially in contact with a medium to be measured, and changes the emission wavelength of the light-emitting element by chemical change. The measured medium is set to a value in a wavelength band in which the measured medium has light absorption sensitivity, and the state of the medium is detected by the output level of the light receiving element. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a diagram for explaining one embodiment of the present invention. In the figure, 11 is a constant current source, and 12 is a light emitting element (light source) such as an LED that generates a constant amount of light by the constant current source 11. ), 13
14 is an optical waveguide into which the light emitted by the light emitting element 12 is introduced; 14 is a light receiving element into which the light propagated through the optical waveguide 13 while being reflected and emitted from the optical waveguide 13 is incident;
Reference numeral 15 denotes a medium to be measured, and the emission wavelength of the light emitting element is set to a value in a wavelength band in which a chemically changed liquid to be measured has light absorption sensitivity. (Organic photoreceptor) Cyclohexanone, which is a solvent for pigments used in the production of drums, or a pigment coating liquid is used. When cyclohexanone is left in the air, the benzene ring opens due to the action of oxygen, water, and light, and it transforms into adipic acid, 5-hexenaldehyde, or caproic acid. As a result of this chemical change, the optical spectrum of the liquid component to be measured changes.

Figure 2 (a) shows the absorption spectrum of a normal liquid;
B) is a diagram showing the absorption spectrum of a liquid that has deteriorated due to oxidation, etc. As shown in the figure, when the light source wavelength is set to the wavelength indicated by the broken line, when the liquid state changes due to deterioration such as oxidation, the absorption peak will appear. , the amount of light absorbed increases with the absorption of the evanescent wave of the propagating light, and the amount of light received by the light receiving element decreases, making it possible to detect a change in state.

Figure 3 shows the absorption spectra of normal cyclohexanone (curve A) and cyclohexanone (amB) that has undergone chemical changes over time. When the wavelength of the light source is around 400 nm, the absorbance of normal cyclohexanone is 0, but that of degraded cyclohexanone. The absorbance is increasing. Therefore, when light is passed through the fiber that constitutes the optical waveguide 13 from transparent resin, glass, etc., a portion of the propagating light seeps out onto the fiber surface and generates evanescent waves, but this evanescent wave is transmitted to the surrounding liquid. Absorption properties reduce the level of fiber output light. That is, when the wavelength of the light source 12 is set to 400 nm, the absorption of the evanescent wave into the chemically changed cyclohexanone 15 increases, so the amount of light received by the light receiving element 14 decreases. Therefore, it becomes possible to measure the state of the liquid due to chemical changes. Furthermore, if the optical waveguide 13 has a bend R, the influence of evanescent waves becomes large, and the absorbance of the evanescent waves to the liquid increases due to the deviation of the absorption peak, and the detection sensitivity to state changes due to chemical changes in the liquid increases. will improve.

Figure 4 shows the results when a fluorescent light passed through a narrow band filter is used as a 400 nm light source, and the optical waveguide through which the light generated from the light source is introduced is immersed in cyclohexanone that has been left for 3 days. This figure shows changes in the relative output value of the light-receiving element, and as is clear from the figure, a change in the state of cyclohexanone can be detected from a decrease in the relative output value of the light-receiving element. In this way, it becomes possible to detect a change in the state of cyclohexanone or a ○PC'' paint using cyclohexanone as a solvent.

As similar liquids, various oils such as hydraulic oil also have a rating of 400 to 500.
Since an absorption peak due to chemical changes due to deterioration etc. appears near nm, it is possible to monitor the deterioration of 5 hydraulic fluids online in the same manner as above. Since the measuring device according to the present invention is an optical measuring device, there is no risk of fire even when used with flammable liquids such as oil.
Note that it goes without saying that the medium to be measured may be in the form of a gel or a sol.

Effects As is clear from the above explanation, according to the present invention, it is possible to measure the condition of a medium with little change in refractive index during quality deterioration using a simple sensor, and it is possible to store a medium with high precision and high reliability in a practical manner. A condition measuring device can be provided.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining an example of the storage state measuring device for a medium according to the present invention, Figure 2 (a) is a diagram showing the absorption spectrum of a normal liquid, and Figure 2 (b) is a diagram showing an absorption spectrum of a deteriorated liquid. Figure 3 is a diagram showing the absorption spectra of normal cyclohexanone and cyclohexanone that has undergone chemical change over time. Figure 4 is a diagram showing the time when cyclohexanone is left in the air and the rate of change in output light amount. The figure is a diagram for explaining an example of a conventional physical property value measuring device. 11... constant current source, 12... light emitting element (light source), 1
3... Optical waveguide, 14... Light receiving element, 15... Measured medium. Figure 1 Figure 3 3IL Moxibustion (nm)

Claims (2)

[Claims] (1) A light-emitting element and a light-receiving element are coupled through an optical waveguide at least partially in contact with a medium to be measured, and the emission wavelength of the light-emitting element is set to a value in a wavelength band in which the chemically changed medium to be measured has light absorption sensitivity. 1. An apparatus for measuring the storage state of a medium, characterized in that a change in the chemical state of the medium is detected based on the output level of the light-receiving element. (2) The optical waveguide has a bend in the optical path at a portion in contact with the medium to be measured, and is made of glass, quartz, or a transparent resin material.
) Storage state measuring device for the medium described in item 1.