JPH01202642A - Measuring apparatus - Google Patents

Abstract

PURPOSE:To enable equalization of an output of a first photoresponsive element in a reference state to that of a second photoresponsive element, by providing a quantity of light adjusting means before the second photoresponsive element into which light from a light source is made incident directly. CONSTITUTION:After reflected diffusively on a surface 2 to be measured, a luminous flux projected to the surface 2 from a light source 1 is made incident into a first photoresponsive element 3 to generate an electric output in the element 3 according to an incident light energy. The reflection factor of incident light energy with respect to the element 3 is determined by a characteristic of an object to be measured and the reflected light thereof is incident into the element 3 according to physical nature of the object being measured. On the other hand, the luminous flux emitted to a second photoresponsive element 4 from the light source 1 is incident into a quantity of light adjusting means 5, with a light energy absorption filter 5a of which 5 the most of the energy is absorbed and incident into the element 4 after scattering reflected light is interrupted with a stop 5b. In this manner, even when there are variations in a relative position relationship between the light source 1 and the element 4, the physical nature of the object being measured can be measured accurately with no remarkable change in the output of the element 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a measuring device for measuring physical properties of substances or objects, and is particularly suitable for measuring changes in concentration over time of an electrophotographic developer. related to a measuring device.

[Prior Art] As is well known, there are two types of electrophotographic developers: one-component developers and two-component developers, and two-component developers are currently widely used. When a developer is repeatedly used in an electrophotographic apparatus, the concentration of the developer decreases, and image quality deteriorates accordingly. Therefore, in order to prevent image quality from deteriorating, it is necessary to constantly measure changes in developer density and replenish new developer in accordance with the decrease in density.

Conventionally, a developer concentration detection device installed in an electrophotographic apparatus includes a light source that projects light onto the developer, and a light receiving element that receives reflected light of the light projected onto the developer from the light source. The detection device detects a change in the concentration of the developer by measuring the electrical output generated from the light receiving element according to the optical energy of the reflected light from the developer. . However, with this developer concentration detection device,
It has been difficult to obtain reliable and accurate detection values because the light source and light receiving element tend to fluctuate in the amount of light they generate and their output depending on the environment in which they are used, and the amount of light they emit and the output decrease over time. Therefore, in order to compensate for fluctuations in detected values due to changes in the usage environment or changes over time, a second light-receiving element is provided to directly receive the light generated from the light source, and a second light-receiving element is provided to receive the light reflected from the developer. An improved developer concentration detection device has been proposed in which the output of one light receiving element is corrected by the output of the second light receiving element.

[Problems to be Solved by the Invention] However, although the above-mentioned developer concentration detection device equipped with the first and second light-receiving elements can compensate for fluctuations in the detected value due to fluctuations in the amount of light emitted from the light source, Since the directivity of the emitted energy of the light source differs slightly for each light source, the relative positional relationship between the light source and the first and second light receiving elements must be very precise. The installation positions of the light source and the light-receiving element must be precisely adjusted for each developer concentration detection device, and therefore, if there are variations in the relative positional relationship of the three, the output will be different from that of each developer concentration detection device. The drawback was that each one was different.

An object of the present invention is to provide an improved developer concentration detection device which eliminates the drawbacks of the known developer concentration detection devices and which does not cause variations in output even if there is some variation in the relative positional relationship between the light source and the light receiving element. Or to provide a measuring device.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, in the present invention, a light amount adjusting means is provided between the light source and the second light receiving element into which the light generated from the light source is directly incident. A feature of the present invention is that the energy incident on the element is adjusted so that the difference between the initial outputs of the first and second light-receiving elements does not become excessive. In addition, in the present invention, by selecting the light source and the light receiving element so that the entire spectral distribution wavelength range of the light emission energy of the light source is included in the sensitivity wavelength range of the light receiving element, the spectral distribution of the light emission energy of the light source and the light reception can be improved. Even if the sensitivity spectral distribution of the element changes over time and due to environmental influences, and there is a difference in the sensitivity spectral distribution between the light receiving elements, the first
The output difference between the second light receiving element and the second light receiving element can be reduced.

[Function] In the measuring device of the present invention, since the light amount adjustment means is provided in front of the second sales movement element into which the light from the light source enters,
Since the reference output of the first sales movement element into which the reflected light from the object to be measured is incident can be made equal to the output of the second sales movement element, highly accurate measurement can be performed. Also,
Even if there is variation in the relative positional relationship between the light source and the marketing element, the accuracy of each measuring device can be made uniform without being affected by the variation.

[Embodiment] Fig. 1 is a diagram showing a first embodiment of the measuring device of the present invention, in which 1 is a light source composed of an LED, 2
is the surface of the object to be measured such as a two-component developer, 3 is the surface of the object to be measured 2
4 is a light source 1;
a second marketing element into which the light generated from the 5 directly enters;
a is a light energy absorbing filter that is a component of the light amount adjustment means 5 provided in the optical path between the light source 1 and the second marketing element 4; and 5b is a diaphragm that is a component of the light amount adjustment means 5. be.

The light source 1 made of LED has an emission peak wavelength of 940 nm.
(nanometers), the half-value wavelength width is 50 nm, and the emission wavelength band is 150 nm. do.

Sales elements 3 and 4 are SPDs with a light receiving aperture of 5.7 mmφ.
It consists of etc. In this embodiment, the light energy absorption filter 5a has a transmittance of 0.9 at a wavelength of 940 nm.
%, transmittance is 1% at wavelength 1150nm to 1100n
It is a filter that is about.

The two-component developer that is the object to be measured is composed of toner and Chiaria, and the toner has a reflectance at a wavelength of 940 nm+ that is approximately 60% that of BaSO4, and Chiaria has a reflectance at a wavelength of 940 nm that is approximately 60% that of BaSO4. 5% or less. In such a two-component developer, the larger the ratio of toner to chiaria, the greater the diffuse reflectance. Therefore, it is possible to measure the ratio of chiaria to toner (i.e., developer concentration) by measuring the reflected light energy. can.

The light beam projected from the light source 1 onto the surface 2 of the object to be measured is
After being diffusely reflected, it enters the first sales movement element 3,
An electrical output is generated in the element 3 according to the energy of the incident light. The reflectance of the incident light energy to the element 3 is determined by the physical properties of the object to be measured (that is, the mixing ratio of toner and Chiaria in this embodiment), and the reflected light according to the physical properties of the object to be measured is The light enters the sales movement element 3.

On the other hand, the light beam emitted from the light source 1 toward the second marketing element 4 enters the light amount adjustment means 5, and most of the energy is absorbed by the light energy absorption filter 5a of the light amount adjustment means 5. Only 0.9 to 1% of the light energy incident on the absorption filter 5a passes through the filter 58, and after the diffusely reflected light is blocked by the diaphragm 5b, it enters the second marketing element 4. In the case of this embodiment, the design is such that the outputs of the first and second promotional elements 3 and 4 are equal when the ratio of chiaria to toner in the two-component developer, which is the object to be measured, is 8%. has been done.

As in this embodiment, when the light amount adjusting means 5 having the above-mentioned characteristics is provided, even if there is variation in the relative positional relationship between the light source 1 and the second sales element-4, the second light-responsive element-4 can be adjusted. The output of No. 4 does not fluctuate significantly, and the physical properties of the object to be measured (in this example, the developer concentration) can be accurately measured.

FIG. 2 shows a second embodiment of the invention. In this embodiment, the light amount adjusting means 5A is composed of a diffusion filter 50 and an aperture 5b. Since the diffusion filter 50 has the same function as the optical energy absorption filter 58 due to its distance from the photoresponsive element 4, even with the configuration of this embodiment, the same effect as that of the first embodiment can be obtained.

Note that the second photoresponsive element 4 is installed at a position farther from the light source 1 than in the first embodiment.

FIG. 3 shows a third embodiment of the present invention. The light amount adjusting means 5B of this embodiment is composed of a polarizing filter 5d and an aperture 5b. Further, the second photoresponsive element 4 is installed at a position farther from the light source 1 than in the first embodiment, thereby reducing the light energy incident on the second photoresponsive element 4, which is applied to the polarizing filter 5d. It has the same function as a light energy absorption filter.

FIG. 4 shows a third embodiment of the present invention. The light amount adjustment means 5C of this embodiment includes a screen filter 58.
and an aperture 5b. As shown in FIG. 5, the screen filters used in the light amount adjusting means 5C include a stripe type screen filter 581, an inverted dot type screen filter 582, a lattice type screen filter 503, a dot type screen filter 584,
Various screen filters such as can be used.

FIG. 6 shows a fourth embodiment of the present invention. The light amount adjustment means 5D of this embodiment rotates relative to each other.
The light amount adjusting means 5D of this embodiment, which has a structure in which more than one polarizing filter 5f and 5g are meshed together and is provided with an aperture 5b, is also the light amount adjusting means shown in FIGS. 1 to 5. It has the same function as .

The light amount adjusting means 5E of the fifth embodiment shown in FIG. 7 is composed of two stripe type screen filters 5h shown in FIG.
and 51 are configured to move in parallel or rotate relative to each other, and is provided with an aperture 5b.

The light amount adjusting means 5F of the sixth embodiment shown in FIG.
As shown in FIG. 0, it is composed of two apertures 5b and 5j that move in parallel or rotate relative to each other.

FIG. 11 is a diagram showing the emission wavelength distribution 21 of the light source 1 and the sensitivity spectral distribution 22 of the photoresponsive elements 3 and 4 in the apparatus of the present invention shown in the first to sixth embodiments. In the device, when the emission wavelength distribution 21 of the light source 1 fluctuates as shown in 21a and 21b due to environmental changes or changes over time, the fluctuation distributions 21a and 21b are prevented from going outside the sensitivity spectral distribution 22 of the photoresponsive elements 3 and 4. The light emission characteristics of the light source 1 and the sensitivity characteristics of the photoresponsive element are selected, and a photoresponsive element is used such that the sensitivity spectral distribution 22 of the photoresponsive element is nearly flat in the emission wavelength range of the light source 1. ing. Therefore, in the device of the present invention, the emission wavelength of the light source 10 fluctuates depending on environmental factors and changes over time, and the two photoresponsive elements 3
Even if there is a slight difference in the sensitivity spectral distribution of each pixel and 4, the mutual output difference between the pixel elements can be made very small, so accurate measurement values can be obtained.

It goes without saying that the light amount adjusting means may be constructed by combining the various filters shown in each of the above embodiments.

[Effects of the Invention] As explained above, in the measuring device of the present invention, the light amount adjustment means is provided in front of the second photoresponsive element into which the light from the light source is directly incident, so that the light intensity adjustment means of the first photoresponsive element is It becomes possible to make the output in the reference state and the output of the second photoresponsive element the same, and as a result, measurement accuracy can be improved.

In addition, in the measuring device of the present invention, environmental changes and aging of the photoresponsive element, variations in the installation position of the light source and the photoresponsive element,
It is possible to adjust the output errors of the two elements due to variations in the characteristics of the responsive elements, etc., and as a result, it is possible to equalize the quality of the individual measuring devices. Furthermore, in the device of the present invention, the light source and the light-responsive element are selected so that the characteristics of the light source and the characteristics of the photoresponsive element are as described above, so even if there are environmental and temporal fluctuations, high measurement performance can be achieved. Accuracy can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the first embodiment of the measuring device of the present invention, and FIG.
The figure is a schematic diagram of a second embodiment of the present invention, Figure 3 is a schematic diagram of a third embodiment of the present invention, Figure 4 is a schematic diagram of a fourth embodiment of the present invention, and Figure 5 is a schematic diagram of a fourth embodiment of the present invention. Figure 6 is a schematic diagram of the fifth embodiment of the present invention, Figure 7 is a schematic diagram of the sixth embodiment of the present invention, and Figure 8 is a diagram showing the types of screen filters used in the embodiments. A diagram showing a striped screen filter used in the seventh embodiment, FIG. 9 is a schematic diagram of the seventh embodiment of the present invention, and FIG. 10 shows a part of the light amount adjustment means in the embodiment of FIG. FIG. 11 is a plan view showing the characteristics of the light source and the characteristics of the photoresponsive element in the device of the present invention. 1... Light source 2... Surface of the object to be measured 3...
First photoresponsive element 4...Second widening element 5, 5A, 5B, 5f;, 5D, 5E, 5
F...Light amount adjustment means 5a...Light energy absorption filters 5b, 5j...Aperture 5C...Diffusion filter 5d...A flattening filter 5e...Screen filter Fig. 1 Diagram 2 M汲艮

Claims (1)

[Scope of Claims] 1. A light source that projects light onto an object to be measured, a first light-responsive element that receives reflected light reflected by the object to be measured and generates an output according to the amount of received light, and the light source. a second light-responsive element that directly receives light generated from the light-responsive element and generates an output according to the amount of received light, the output of the first light-responsive element and the output of the second light-responsive element. A measuring device for measuring the physical properties of the object to be measured based on the difference between the light source and the second photoresponsive element, characterized in that a light amount adjusting means is provided in the optical path between the light source and the second photoresponsive element. . 2. The measuring device according to claim 1, wherein the light amount adjusting means has a light absorption filter. 3. The measuring device according to claim 1, wherein the light amount adjusting means has a diffusion filter. 4. The measuring device according to claim 1, wherein the light amount adjusting means has a structure in which at least two polarizing filters are stacked one on top of the other. 5. The measuring device according to claim 1, wherein the light amount adjusting means has a structure in which at least two polarizing filters that are relatively rotatable are stacked one on top of the other. 6. The measuring device according to claim 1, wherein the light amount adjusting means has a screen filter. 7. The measuring device according to claim 1, wherein the light amount adjusting means has a structure in which at least two or more stripe screen filters that can be moved in parallel or rotated relative to each other are stacked one on top of the other. 8. The measuring device according to claim 1, wherein the light amount adjusting means has a diaphragm that can be rotated or translated in parallel. 9. The measuring device according to claim 1, wherein the light amount adjusting means has at least two or more apertures that can rotate or move in parallel relative to each other. 10. The measuring device according to claim 1, wherein the light amount adjusting means is configured by combining two or more of a light absorption filter, a diffusion filter, a polarizing filter, a screen filter, and an aperture. 11. A claim in which the light amount adjusting means is constructed by combining two or more of a light absorption filter, a diffusion filter, a polarizing filter, a screen filter, and an aperture, and the filter or aperture is configured to be relatively movable. Item 1. Measuring device according to item 1. 12. The measuring device according to claim 1, wherein the sensitivity wavelength range of the first and second photoresponsive elements is wider than the emission energy wavelength range of the light source. 13. The measuring device according to claim 12, wherein in the sensitivity wavelength range of the first and second photoresponsive elements, a portion of the emission energy wavelength range of the light source is a flat sensitivity range. 14. The measuring device according to any one of claims 1 to 13, wherein the measuring device is a device for measuring changes in physical properties of a substance such as a powder or a granular material. 15. The measuring device according to any one of claims 1 to 14, wherein the measuring device is a device for measuring the concentration of an electrophotographic developer.