JP2001108618A - Toner image concentration-detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner image concentration-detecting device that cannot be easily affected by such environmental change as temperature and humidity and aging. SOLUTION: The toner image concentration-detecting device is provided with a photo detector for receiving toner image reflection light that is emitted from a light-emitting device, is reflected by a toner image, and passes through a toner image diffusion reflection light incidence light path, or diffusion plate reflection light that passes through a diffusion plate incidence/reflection light path where a diffusion plate is arranged halfway and is reflected by the diffusion plate, a device for adjusting the quantity of diffusion plate reflection light, a reference light detection position that allows light to pass by making connection to the diffusion plate incidence/reflection light path and at the same time breaks the toner image diffusion reflection light incidence light path, and a shutter that breaks the diffusion plate incidence/reflection light path and at the same time can travel at an area to the toner image reflection light detection position for making connection to the toner image reflection light incidence light path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner image density detecting device used in an image forming apparatus, and more particularly, to a density image formed to adjust a density of a toner image formed in the image forming apparatus to an appropriate value. The present invention relates to a toner image density detecting device that detects the density of a toner image for measurement. The toner image density detecting device is particularly configured such that a rotating photosensitive member surface is uniformly charged by a charging member, an electrostatic latent image is written on the charged photosensitive member surface with laser light, and the electrostatic latent image is developed by a developing device. The image forming apparatus is preferably used in an image forming apparatus in which the toner image on the surface of the photoconductor is transferred directly or indirectly through an intermediate transfer member to a recording sheet. In order to adjust the image density of the toner image actually formed on the surface of the recording sheet to an appropriate density according to the detected toner image density, the charging potential of the photoconductor surface by the charging member, the laser power, or the developing device The development bias and the like are adjusted.

[0002]

2. Description of the Related Art (Description of the prior art shown in FIG. 12A) FIG.
FIG. 12A is an explanatory view of a conventional example of a toner image density detecting device for detecting the density of the toner image. FIG. 12A shows a state of detecting diffuse reflection light from a toner image for density detection formed on a toner image carrying surface. FIG. 12B is a diagram showing a state in which the amount of diffusely reflected light from the toner image carrying surface on which no toner image is formed is detected. In FIG. 12A, in order to detect the density of the toner image Tn for density measurement formed on the toner image holding surface S such as the photoconductor surface or the intermediate transfer belt surface,
A toner image density detecting device 01 is used. The toner image density detecting device 01 includes a light emitting element 02 that irradiates the toner image Tn with light L1 for diffuse reflection detection, and a light receiving element that receives light L2 emitted from the light emitting element 02 and diffused and reflected by the toner image Tn. It has elements 03 and a detection element support member 04 that supports them.

[0003] The detection element support member 04 includes a support member main body 0.
5, an optical path forming member 06 joined to one end surface thereof, and a transparent dustproof member 07 joined to the optical path forming member 06. The light emitting element 0 is provided on the support member body 05.
2, a light emitting element housing part 05a for housing
3 for receiving the light receiving element 0b,
3, an incident optical path 05c of the diffuse reflected light L2 from the toner image Tn from the toner image Tn is formed. Optical path forming member 06
A light path 06a for emitting a light beam L1 emitted from the light emitting element 02 toward the external toner image Tn, and a light beam L2 diffused and reflected by the toner image Tn. An incident optical path 06b for entering the element 03 is formed. The incident optical paths 05c and 06b cause the toner image diffuse reflected light incident optical path (06b
+ 05c).

When the density of a toner image is detected by the toner image density detecting device 01 shown in FIG. 12A, a toner image Tn for density detection is formed on the surface of a photoreceptor of an image forming apparatus or a surface of an intermediate transfer belt or the like. The light L1 emitted from the light emitting element 02 is irradiated on the toner image Tn, and the light quantity of the light L2 diffusely reflected on the toner image Tn is detected by the light receiving element 03.
The toner image Tn is Y (yellow), M (magenta),
In the case of K (color toner other than black toner) such as C (cyan), assuming that the amount of the emitted light L1 is constant,
As the amount of toner adhered to the toner image Tn increases, the amount of light detected by the light receiving element that detects the amount of diffused light increases, and as the amount of toner adhered decreases, the amount of diffused light detected by the light receiving element decreases. Therefore, at the time of actual image formation, the density parameter (a parameter that affects the toner image density, that is, the image carrier charge amount, the laser power, the developing bias, and the By changing one or a combination of two or more of the developer amount of the two-component developer).
It is possible to adjust the toner image density to a predetermined value.

However, when the toner image density detecting device 01 shown in FIG. 12A detects the density of a toner image, the following problem arises. (1) Output values of the light emitting element 02 and the light receiving element 03 change due to environmental changes such as temperature and humidity. (2) The output values of the light emitting element 02 and the light receiving element 03 change (decrease) due to deterioration over time. The relationship between the toner image density and the value of the detected diffused light quantity changes due to the above (1) and (2). If the density parameter is controlled so that the value of the detected diffused light quantity is constant as described above, The actual toner image density deviates from the desired toner image density. FIG. 14 is a graph showing the relationship between the toner adhesion amount (toner density) and the output value (detected diffusion light amount) of a sensor (toner image density detector). As can be seen from FIG. 14, when the sensor output changes due to environmental changes such as temperature and humidity or changes over time, the toner adhesion amount δD differs even if the sensor output is the same.

The following techniques are known in the art for compensating environmental changes or changes over time such as temperature and humidity of the performance of the light emitting element 02 and the light receiving element 03. As shown in FIG. 12B, the amount of diffusely reflected light H0 from the toner image carrying surface S where the toner image Tn is not formed is detected. And H0,
H1 and H are defined as follows. H0: A detection value of the amount of diffusely reflected light from the toner image carrying surface S on which the toner image of FIG. 12B is not formed. H1: A detected value of the amount of diffusely reflected light from the toner image Tn formed on the toner image carrying surface S in FIG. 12A. H: a sensor output correction value in consideration of a change in the output value of the light emitting element or the light receiving element due to a change in environment or a change over time. H can be expressed by the following equation. H = H1 / H0 If the diffuse reflectance of the toner image bearing surface S and the diffuse reflectance of the toner image attached to the toner image bearing surface S are fixed,
Even if the output value of the light emitting element or the light receiving element changes, H1 and H0
So that the value of the ratio (that is, H) becomes a predetermined value, a density parameter (a parameter that affects the toner image density,
That is, by changing any one or a combination of the charge amount of the image carrier, the laser power, the developing bias, the amount of the developer in the developing device, the toner concentration when using a two-component developer, and the like, It is possible to adjust the toner image density to a predetermined value.

However, even when such a correction value is used, the state of the toner image carrying surface changes over time during actual image formation (for example, the surface roughness changes due to frictional contact with the cleaning member). H0 (detected value of the amount of diffusely reflected light from the toner image carrying surface S) changes, and H0 with respect to a desired density is changed.
(Sensor output correction value) changes. If the density parameter is controlled in such a state, a problem occurs that the actual toner image density deviates from the desired toner image density. As described above, in a device that controls the toner image density based on the output value of the sensor, it is generated due to deterioration of the sensor (environmental change of light emitting element and light receiving element, change of output over time), change of reflection characteristic of the toner image carrying surface, and the like. In order to reduce the variation in image density, the present inventors have previously filed a patent application (Japanese Patent Application No. 11-05761) for the toner image density detection device shown in FIG.

FIG. 13 is an explanatory view of another conventional example of a toner image density detecting device for detecting the density of the toner image. FIG. 13A is formed on a toner image carrying surface. FIG. 13B shows a state in which diffuse reflection light from a toner image for density detection is detected. FIG. 13B detects the amount of diffuse reflection from a toner image carrying surface on which a toner image is not formed and the diffuse light reflected by a diffuse reflection plate. It is a figure showing a state.
In FIG. 13, elements corresponding to those in FIG. 12 are denoted by the same reference numerals, and redundant description will be omitted.

13A and 13B, the toner image density detecting device 01 has a diffusion plate 08. The light path forming member 06 of the detection element support member 04 includes a diffusion plate housing portion 06c for housing the diffusion plate 08, and a diffusion plate incident optical path for causing a part L3 of light emitted from the light emitting element 02 to enter the diffusion plate 08. 06d is provided. The support member main body 05 of the detection element support member 04 is provided with a diffuser plate reflection optical path 05d for making the light L4 diffusely reflected by the diffuser plate 08 incident on the light receiving element 03. The diffuser incident light path 06d and the diffuser reflection light path 05d form a diffuser incident light path (06d + 05d). The other configuration of the toner image density detecting device 01 of FIG.
A is the same as the toner image density detection device 01 shown in FIG.

The toner image density detecting device 0 shown in FIG.
As shown in FIG. 13B, 1 detects the amount of diffuse reflection light H0 from the toner image carrying surface S on which the toner image Tn is not formed and the diffusion plate 08. And H0, H1 and H
Is defined as follows. H0: Detected value of the amount of diffusely reflected light from the toner image carrying surface S where the toner image of FIG. 13B is not formed and the diffusion plate 08. H0 in this case is given by the following equation (1).
Can be represented by H0 = H0a + H0b (1) where H0a is the toner image carrying surface S on which no toner image is formed.
The amount of diffusely reflected light detected from H0b: A detection value of the amount of diffusely reflected light from the diffusion plate 08.

H1: A detection value of the toner image Tn formed on the toner image carrying surface S of FIG. 13A and the amount of diffuse reflection light from the diffusion plate 08. H1 in this case can be expressed by the following equation (2). H1 = H1a + H1b (2) where H1a is the amount of diffusely reflected light detected from the toner image formed on the toner image carrying surface S. . H1b: A detection value of the amount of diffusely reflected light from the diffusion plate 08. Note that the detection values H0b and H1b of the amount of diffusely reflected light from the diffusion plate 08 are the same, and the following expression (3) holds. H1b = H0b ……………………………………… (3)

When the toner image density is controlled by using the toner image density detecting device 01 shown in FIG.
By setting the sensor output correction value of (1) as the target value, the toner image density can be adjusted to a predetermined value. H: H = H1 / H0 = (H1a + H1b) / (H0a + H0b) (4)

In the toner image density detecting device 01 shown in FIG. 13, even when the light emission amount of the light emitting element changes due to, for example, environmental change, deterioration over time, etc., the object to be measured (image carrier,
Since the ratio of the amount of the emitted light L1 to the toner on the image carrier and the amount of the emitted light L3 to the diffusion plate is constant without change, a sensor output correction value without fluctuation can be obtained. However, even in this case, if the light reflection characteristic of the image carrier changes, the sensor output correction value still has an error. As one measure against this, H0a << H0b, that is, by setting the degree of influence on the reflection surface of the image carrier to be small,
It is possible to obtain a sensor output correction value with relatively little fluctuation, and it is possible to correct the toner image density as desired. In addition, even when the amount of light received by the light receiving element changes, the ratio of the total amount of received light (see the above equation (4)) is taken, so that the toner image density can be corrected without any major problem. .

[0014]

The conventional toner image density detecting device 01 shown in FIG. 13 has the following problems. (1) In a plurality of toner image density detecting devices, when the mounting accuracy of each light emitting element 02, light receiving element 03, and diffusion plate 08 varies, the sensor output between different toner image density detecting devices is measured in the same amount of toner adhesion. The correction value changes. For example, the ratio of the amount of the emitted light L1 to the object to be measured (image carrier, toner image on the image carrier, etc.) and the amount of the emitted light L3 to the diffusion plate changes between the respective toner image density detection devices. The value of H1 / H0 differs between the devices. For this reason, the toner image density varies in each image forming apparatus in which the toner image density is controlled by each toner image density detecting device. (2) There is a possibility that natural light or other turbulent light may be included in the detection of the reflected light from the diffuser plate. In such a case, a variation in the sensor output correction value H occurs, and a desired toner image density is obtained. On the other hand, there occurs a problem that the actual toner image density is shifted. (3) The amount of received light detected by the light receiving element of the toner image density detecting device in FIG. 13 is a sum of the amount of reflected light from the measured object and the amount of reflected light from the diffusion plate. Since the amount of light reflected from the reference plate is not directly related to the original detection of the toner image density, there is a concern that the detection accuracy of the toner image density is reduced. Further, when the relationship of H0a << H0b is set so that the degree of influence on the reflection surface of the image carrier is reduced as described above, the ratio of the amount of light which is not directly related to the detection of the toner image density is further increased. Because
There is a concern that the accuracy of the detection of the original toner image density is reduced.

In view of the above circumstances, the present invention provides the following (O01)
To (O03). (O01) To provide a toner image density detecting device which is hardly affected by environmental changes such as temperature and humidity and temporal changes. (O02) To reduce variations among the toner image density detecting devices when detecting the densities of toner images having the same density.
(The value obtained by dividing the toner image diffuse reflection light amount by the correction reference light amount should be the same value between the respective toner image density detection devices.) (O03) To obtain the detected light amount of the appropriate toner image density thing. (Adjust the light emission amount of the light emitting element.)

[0016]

Means for Solving the Problems Next, the present invention for solving the above-mentioned problems will be described. Elements of the present invention are described in order to facilitate correspondence with the elements of the embodiments described later. The sign of parentheses is added in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the following embodiments is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

(1st invention) In order to solve the aforementioned problem,
The toner image density detecting device of the first invention has the following requirements (A01).
To (A06). (A01) Diffusion plate (18) that diffusely reflects incident light, (A0
2) A light emitting element (21) for irradiating the diffuser plate (18) and the toner image (Tn) with light for detecting diffuse reflection light, (A0
3) a light receiving element (23) for receiving light emitted from the light emitting element (21) and diffusely reflected by the toner image (Tn) or the diffusion plate (18); (A04) housing the diffusion plate (18); A diffusion plate accommodating portion (13) and the light emitting element (2);
1) a light-emitting element housing part (2) for housing the light-receiving element (23), a light-receiving element housing part (3) for housing the light-receiving element (23), and a part of light emitted from the light-emitting element (21). 1
8) a diffuser incident optical path having a diffuser incident optical path (12) and a diffuser reflective path (8) for causing light reflected by the diffuser (18) to enter the light receiving element (23); A toner image irradiation light emitting optical path for emitting another part of the light emitted from the element (21) toward the external toner image (Tn); and a toner image diffuse reflection light diffusely reflected by the toner image (Tn). (K05) a detection element support member having a toner image diffuse reflection light incident optical path for causing light to enter the light receiving element (23), and (A05) outer ends of the toner image diffuse reflection light incident light path and the toner image irradiation light emission light path. A transparent dustproof member (19) provided in a portion, (A06) a diffuser plate which is a light amount emitted from the light emitting element (21), reflected by the diffuser plate (18), and then incident on the light receiving element (23). Diffuse plate reflection light amount adjustment to adjust the reflection light amount Knot device (24 + 25 + 26).

(Operation of the First Invention)
In the toner image density detecting device of the invention, the light emitting element (21)
Irradiates the diffuser plate (18) and the toner image (Tn) with light for diffuse reflection light detection. The diffusion plate (18) diffusely reflects the incident light. The light receiving element (23) is provided with the light emitting element (2).
Light emitted from 1) and diffusely reflected by the toner image (Tn) or the diffusion plate (18) is received. The light emitting element (21), the diffusion plate (18), and the light receiving element (23) are accommodated in a detection element support member (K), and the detection element support member (K) includes a toner emitted from the light emission element (21). An image irradiation light emission optical path and a toner image diffuse reflection light incident optical path for causing the toner image diffuse reflection light diffusely reflected by the toner image (Tn) to enter the light receiving element (23). Outer ends of the toner image diffuse reflection light incident light path and the toner image irradiation light emission light path are closed by a transparent dustproof member (19).

The detecting element support member (K) transfers a part of the light emitted from the light emitting element (21) to the diffusion plate (1).
8) a diffuser incident light path having a diffuser incident light path (12) and a diffuser reflection light path (8) for making the light reflected by the diffuser (18) incident on the light receiving element (23); I have. The diffused plate reflected light amount detected by the light receiving element (23) through the diffused plate incident / reflected light path corrects the toner image diffuse reflected light amount (the light amount corresponding to the toner image density) which fluctuates due to the environmental change or the temporal change. Used when doing.

Diffusing plate reflection light amount adjusting device (24 + 25 + 2)
6) adjusting the amount of light reflected by the diffuser plate, which is the amount of light emitted from the light emitting element (21), reflected by the diffuser plate (18) and then incident on the light receiving element (23), to an appropriate value. it can. For example, when a plurality of toner image density detecting devices (U) are manufactured, a light emitting element (21), a light receiving element (23),
The mounting position of the diffusion plate (18) varies among the devices. As an example, when the mounting position of the light emitting element (21) is changed, the distribution ratio of the amount of light emitted from the light emitting element (21) to the object to be measured (toner image) and the amount of light incident on the diffusion plate is determined by each device. Will change between them. Then, the ratio H (H = H1 / H0) of the diffuse reflection light amount H1 of the measurement object (toner image) and the diffuser plate reflection light amount H0 changes between the respective devices, and the measurement of the toner image density is performed even with the same toner adhesion amount. Since the result will be different, the detected concentration varies among the devices.

That is, each toner image density detecting device (U)
It is a problem that the distribution ratio between the amount of light emitted from the light emitting element (21) to the object to be measured (toner image) and the amount of light incident on the diffuser plate (18) changes. Therefore,
In the first invention, the diffuser reflection light amount adjusting device (24 + 25 +
According to 26), the amount of light incident on the diffusion plate can be adjusted, and the distribution ratio between the amount of light irradiated on the object to be measured (toner image) and the amount of light incident on the diffusion plate can be adjusted to a predetermined value. Therefore, it is possible to reduce the variation in the output correction value H (the ratio between the diffuse reflection light amount H1 of the measured object (toner image) and the diffuser plate reflection light amount H0) between the respective toner image density detection devices, and a predetermined toner density. Can be controlled.

(Second Invention) The toner image density detecting device of the second invention has the following requirements (A01) to (A05) and (A07).
It is characterized by having. (A01) Diffusion plate (18) that diffusely reflects incident light, (A0
2) A light emitting element (21) for irradiating the diffuser plate (18) and the toner image (Tn) with light for detecting diffuse reflection light, (A0
3) a light receiving element (23) for receiving light emitted from the light emitting element (21) and diffusely reflected by the toner image (Tn) or the diffusion plate (18); (A04) housing the diffusion plate (18); A diffusion plate accommodating portion (13) and the light emitting element (2);
1) a light-emitting element housing part (2) for housing the light-receiving element (23), a light-receiving element housing part (3) for housing the light-receiving element (23), and a part of light emitted from the light-emitting element (21). 1
8) a diffuser incident optical path having a diffuser incident optical path (12) and a diffuser reflective path (8) for causing light reflected by the diffuser (18) to enter the light receiving element (23); A toner image irradiation light emitting optical path for emitting another part of the light emitted from the element (21) toward the external toner image (Tn); and a toner image diffuse reflection light diffusely reflected by the toner image (Tn). (K05) a detection element support member having a toner image diffuse reflection light incident optical path for causing light to enter the light receiving element (23), and (A05) outer ends of the toner image diffuse reflection light incident light path and the toner image irradiation light emission light path. A transparent dustproof member (19) provided in the section, (A07) a reference light detection position for connecting the diffused plate entering / reflecting optical path to allow light to pass therethrough and blocking the toner image diffuse / reflected light incident optical path; Block the reflected light path entering the diffusion plate. A shutter (31) movable to and from a toner image reflected light detection position for disconnecting the toner image diffuse reflected light incident optical path.

(Operation of the Second Invention)
In the toner image density detecting device of the invention, the light emitting element (21)
Irradiates the diffuser plate (18) and the toner image (Tn) with light for diffuse reflection light detection. The diffusion plate (18) diffusely reflects the incident light. The light receiving element (23) is provided with the light emitting element (2).
Light emitted from 1) and diffusely reflected by the toner image (Tn) or the diffusion plate (18) is received. The light emitting element (21), the diffusion plate (18), and the light receiving element (23) are accommodated in a detection element support member (K), and the detection element support member (K) includes a toner emitted from the light emission element (21). An image irradiation light emission optical path and a toner image diffuse reflection light incident optical path for causing the toner image diffuse reflection light diffusely reflected by the toner image (Tn) to enter the light receiving element (23). Outer ends of the toner image diffuse reflection light incident light path and the toner image irradiation light emission light path are closed by a transparent dustproof member (19).

The detecting element support member (K) transmits a part of the light emitted from the light emitting element (21) to the diffusion plate (1).
8) a diffuser incident light path having a diffuser incident light path (12) and a diffuser reflection light path (8) for making the light reflected by the diffuser (18) incident on the light receiving element (23); I have. A shutter (31) for switching the optical path of light incident on the light receiving element is provided inside the toner image density detecting device (U). Note that this shutter detects a position A where only the amount of light diffusely reflected from the diffusion plate out of the amount of light emitted from the light emitting element (21), and an object ( (The toner image, the surface of the image carrier, etc.).

Now, it is assumed that a reference having a constant reflectance is provided on the image bearing surface (S). At this time, when the amount of reflected light from the reference object is measured by the toner image density detecting device (U), first, the shutter is set to the object to be measured (toner image, image carrier surface, etc.).
Is set to position B where only the amount of light diffusely reflected from is detected. That is, the light amount diffusely reflected from the diffusion plate is set not to be incident. At this time, the output value temporarily detected by the toner image density detection device M is set to X1. Next, the shutter is set at a position A where only the amount of light diffusely reflected from the diffusion plate is detected. That is, a state is set in which the quantity of light diffusely reflected from the object to be measured (toner image, image carrier surface, etc.) is not incident. At this time, the output value detected by the toner image density detecting device M is assumed to be Y1. At this time, as described above, the object to be measured (toner image, image carrier surface, etc.)
The ratio between the amount of light diffusely reflected from the light source and the amount of light diffusely reflected from the diffuser is used as an output correction value. Here, suppose that the output correction value of the toner image density detecting device M is HM1 and HM1 =
X1 / Y1. Next, the amount of reflected light from the object to be measured in the case of the toner image
2. If the amount of light diffusely reflected from the diffuser is Y2 and the output correction value is HN1, HN1 = X2 / Y2. Here, in the toner image density detectors M and N, as described above, the HM1
≠ HN1. Here, if it is possible to set HM1 = approximately HN1, it is possible to suppress variations in the output correction value of the toner image density detecting device. Therefore, if X1> X2, the amount of light Y2 diffusely reflected from the diffusion plate of the toner image density detection device N can be obtained by the diffusion plate reflection light amount adjustment device.
Is adjusted in the direction of decreasing the amount of light, and when X1 <X2, the amount of light is adjusted in the direction of increasing the amount of light, so that the output correction value of each toner image density detecting device becomes a predetermined value (HM1 = about HN).
Adjustment to 1) becomes possible. That is, the output correction value of each toner image density detecting device {the ratio of the amount of light diffusely reflected from the object to be measured (reference reflector) to the amount of light diffusely reflected from the diffuser} can be adjusted to a constant value. It is possible to adjust the toner image density without variation between the detection devices. In this case, even if the mounting state of the diffusion plate changes between the toner image density detecting devices, there is no problem because the output correction value is adjusted with the fluctuation. Also, even if the output of the light emitting element or the amount of light received by the light receiving element changes due to environmental changes or deterioration over time, the output correction value is calculated based on the amount of light diffusely reflected from the device under test (reference reflector) and the diffuser. Since it is a ratio of the amount of light diffusely reflected, once adjusted, it is a constant and constant value. Therefore, by adopting the configuration of the present invention, it is possible to provide a toner image density detecting device which is not affected by an output change due to the element environment or deteriorated with time without any difference between devices.

[0026]

(Embodiment 1) Embodiment 1 of a toner image density detecting apparatus according to the present invention is characterized in that the first invention has the following requirement (A07). (A07) A reference light detection position for blocking the incident light path of the toner image diffuse reflection light by connecting the reflection light path entering the diffusion plate so that light can pass therethrough; A shutter (31) movable to and from a toner image reflected light detection position that communicates the image diffuse reflected light incident optical path;

(Effect of Embodiment 1) In Embodiment 1 of the toner image density detecting device of the present invention having the above-described configuration, the detection is performed in a state where the shutter (31) is moved to the toner image reflected light detection position. The diffused reflected light amount of the toner image does not include the diffused reflector light amount which is not directly related to the toner image density. For this reason, since the toner image diffuse reflection light amount detects only the light amount that changes according to the toner image density, the toner image density can be detected with high accuracy. Further, when the shutter (31) is used, when adjusting the diffused plate reflected light amount H0 by the diffused plate reflected light amount adjusting device (24 + 25 + 26), the light amount diffusely reflected from the measured object (toner image, image carrier surface, etc.). Is set in such a manner that the light is not incident (the light is not affected by the light (light emitting element, natural light, other scattered light, etc.) from the toner image density detection optical path). Irrespective of this, the amount of reflected light H0 of the diffuser can be adjusted. For this reason, when a reference object having a constant reflectance is provided on the image carrying surface S, when the amount of reflected light is detected by each of the plurality of toner image density detecting devices (U), each toner image density detecting device (U) The ratio H = H of the amount of reflected light H1 of the toner image to the amount of reflected light H0 of the diffuser plate
H0 can be adjusted so that 1 / H0 is constant. Therefore, it is possible to adjust the distribution ratio between the amount of light irradiated on the object to be measured (toner image) and the amount of light incident on the diffusion plate to a predetermined value, and it is possible to correct the toner image density.

(Embodiment 2) Embodiment 2 of the toner image density detecting apparatus of the present invention is characterized in that the following requirements (A08) to (A011) are provided in the first invention or Embodiment 1. And (A08) Regular reflection light detecting light emitting element (22) for irradiating regular reflection light detecting light to the toner image (Tn), (A09) Regular reflection light containing the regular reflection light detecting light emitting element (22) A light emitting element housing for detection (2), a light path for regular reflection light detection for emitting light emitted from the light emitting element for regular reflection light detection (22) toward an external toner image (Tn), The detection element support member (K) having a toner image regular reflection light incident path for causing the toner image regular reflection light (L6) regularly reflected by the toner image (Tn) to enter the light receiving element (23);
0) A transparent dustproof member (19) provided at an outer end of the emission optical path for specular reflection light detection and the optical path of toner image regular reflection light incidence.
(A011) The detection element support member (K) having the toner image regular reflection light incidence optical path configured to also serve as the toner image diffusion reflection light incidence optical path.

(Effect of Embodiment 2) In Embodiment 2 of the toner image density detecting device of the present invention having the above-described configuration, the light emitting element (22) for detecting regular reflection light is used to detect the toner image (Tn). Irradiates light for reflected light detection. The detection element support member (K) includes a regular reflection light detection light emitting element housing section (2) that houses the regular reflection light detection light emitting element (22) and the regular reflection light detection light emitting element (22). A regular reflection light detection light path for emitting the emitted light toward an external toner image (Tn), and a toner image regular reflection light (L6) regularly reflected by the toner image (Tn) to the light receiving element (23). ), And the optical path of the toner image regular reflection light to be made incident on the light source. A transparent dust-proof member (19) provided at the outer end of the regular reflection light detection output light path and the toner image regular reflection light incident light path can prevent dust from entering. The density of the black toner image can be detected by detecting the amount of specular reflection from the toner image (Tn). In addition, the detection element support member (K) is configured so as to serve both as the toner image diffuse reflection light incident optical path and the toner image regular reflection light incident optical path. Therefore, both the toner image diffuse reflection light and the toner image regular reflection light (L6) can be detected by one light receiving element (23).

A general color image forming apparatus is K
A full-color image is created by combining four color toners (black), Y (yellow), M (magenta), and C (cyan). In the above-described toner image density detecting device for detecting the toner image density using the diffused light, the amount of reflected light cannot be detected because the black toner does not reflect the diffused light. Therefore, the second embodiment is a toner image density detecting apparatus that combines a conventional density detecting method using regular reflection light for detecting the density of black toner and a density detecting method using diffuse reflection light for detecting the density of color toner. That is, at the time of detecting the density of the black toner, the regular reflection light emitting element (22) emits light, and the density of the regular reflection light returned from the measured object is detected by the amount of light received by the shared light receiving element (23) (at this time, When the density of the color toner is detected, the light emitting element (21) emits light and the density of the diffuse reflected light returned from the object is detected by the amount of light received by the shared light receiving element (23). Things. (At this time, the light emitting element (21) for detecting diffuse reflection light is turned off).
In this case, a light-emitting element (22) for detecting the density of a black toner image and a light-receiving element (23) shared with a light-emitting element (21) for detecting the density of a color toner image are provided. In the second embodiment of the toner image density detecting device according to the present invention having the above configuration, the diffusion plate (1) provided inside the detecting element support member (K) is provided.
By adjusting (changing) the mounting position (height) or mounting angle of 8), the amount of light (the amount of light reflected by the diffuser plate) incident on the light receiving element (23) can be adjusted.

(Embodiment 3) Embodiment 3 of the toner image density detecting apparatus of the present invention is the same as that of Embodiment 1 or Embodiment 1 of the first invention or the following requirement (A012).
It is characterized by having. (A012) A shutter driving device for driving the shutter (31) between a reference light detection position and a toner image reflected light detection position.

(Operation of the Third Embodiment) In the third embodiment of the toner image density detecting apparatus of the present invention having the above-mentioned configuration, the shutter driving device moves the shutter (31) to the reference light detecting position and the toner image reflection. Drive between the light detection position. Therefore, the operation of the shutter (31) can be automated. For example, a keep solenoid as a drive source of the shutter (31) is connected to the shutter (31), and the reference light detection position is set when the solenoid is sucked, and the toner image reflected light detection position is set when the solenoid is opened.

(Embodiment 4) In Embodiment 4 of the toner image density detecting apparatus of the present invention, the following requirement (A013) is required in Embodiment 1 or Embodiment 1 or 2 of the first invention.
It is characterized by having. (A013) The diffused plate reflected light emitted from the light emitting element (21), reflected by the diffuser plate (18), and then incident on the light receiving element (23) is only diffuse reflected light not including specular reflected light. The light emitting element (21), the diffusion plate (18), and the light receiving element (23) arranged at positions.

(Effect of Embodiment 4) In Embodiment 4 of the toner image density detecting apparatus of the present invention having the above configuration, the light is emitted from the light emitting element (21) and reflected by the diffusion plate (18). After that, the diffused plate reflected light incident on the light receiving element (23) is only diffuse reflected light not including specular reflected light. The diffused plate reflected light detected by the light receiving element (23) is used as correction reference light. However, since the light is hardly affected by external light entering from outside, the correction reference light does not fluctuate due to external light. ,Stabilize. The specularly reflected light is greatly affected by the variation in the amount of received light even when the mounting position or angle of the diffuser plate (18) or the like is slightly changed due to, for example, a rise in temperature. However, if only the diffused light is detected as the reference light detection of the light receiving element (23) (it is hardly affected by the attachment of the diffusion plate because the light is diffused in the first place), the influence of the above-described problem is reduced. It is possible to

(Embodiment 5) The toner image density detecting apparatus according to Embodiment 5 of the present invention satisfies the following requirement (A014) in any of Embodiments 1 to 3 of the first invention or the first invention. It is characterized by having. (A014) The diffused plate reflected light amount adjusting device (24 + 25 + 2) having a light amount adjusting member for adjusting the amount of light passing through the diffused plate incident / reflected light path and entering the light receiving element (23).
6). The diffuser reflection light amount adjusting device (24 + 25 + 2)
6) adjusting the position of a member that partially blocks the diffused light path entering / reflecting the diffuser, adjusting the position and orientation of the diffuser (18), and adjusting (changing) the reflectance of the diffuser (18). ) Is possible.

(Effect of Embodiment 5) In Embodiment 5 of the toner image density detecting device of the present invention having the above-described configuration, the diffusion plate is controlled by the light amount adjusting member of the diffuser reflection light amount adjusting device (24 + 25 + 26). It is possible to adjust the amount of reflected light from the diffuser (the reference amount of light for correction) passing through the incident light path.

(Embodiment 6) The embodiment 6 of the toner image density detecting apparatus according to the present invention satisfies the following requirement (A015) in any of the first and the first to third embodiments of the present invention. It is characterized by having. (A015) The diffuser reflection light amount adjusting device (24 + 25 + 26) having a diffuser position adjusting member for adjusting the position or the mounting angle of the diffuser (18).

(Effect of Embodiment 6) In Embodiment 6 of the toner image density detecting apparatus of the present invention having the above configuration, the diffusion plate position adjusting member of the diffuser reflection light amount adjusting device (24 + 25 + 26) adjusts the diffusion by the diffusion plate position adjusting member. By adjusting the position or the mounting angle of the plate (18), the amount of light reflected by the diffuser plate (reference light amount for correction) can be adjusted.

(Embodiment 7) Embodiment 7 of the toner image density detecting apparatus of the present invention is characterized in that the following requirements (A016) and (A017) are provided in Embodiment 2. (A016) The cleaning member (42) for wiping dust adhered to the surface of the transparent dustproof member (19), (A017) The cleaning member (42) in conjunction with the movement of the shutter (31) driven by the shutter driving device. A) a cleaning member driving member for driving the cleaning member.

(Operation of Embodiment 7) In Embodiment 7 of the toner image density detecting device of the present invention having the above-described configuration, the cleaning member (42) adheres to the surface of the transparent dustproof member (19). Wipe off dust. The cleaning member driving member drives the cleaning member (42) in conjunction with the movement of the shutter (31) driven by the shutter driving device. Therefore, the cleaning member (42) wipes off dust adhering to the surface of the dustproof member (19) in conjunction with the movement of the shutter (31). As described above, even if the ratio H = H1 / H0 of the amount of reflected light H1 of the toner and the amount of reflected light H0 of the diffuser plate is initially set to be constant, toner, dust, and the like are not applied to the transparent dustproof member (19). If adhered, the amount of reflected toner H1 changes, and the output of the light receiving element changes. To prevent such a problem, the cleaning member (4
According to 2), the surface of the transparent dust-proof member (19) is rubbed to remove attached matter. In the operation of the cleaning member (42), the cleaning member (4) operates in conjunction with the shutter (31). For example, when the shutter (31) is at the reference light detection position.
2) is also a position for blocking the optical path, and when the shutter (31) is at the toner image reflected light detection position, the cleaning member (42) is a position for opening the optical path. Further, since the cleaning member driving member is linked with the shirt (31),
It is possible to receive driving from a driving device of the shutter (31).

(Embodiment) Next, a specific example (embodiment) of an embodiment of the toner image density detecting device of the present invention will be described with reference to the drawings, but the present invention is limited to the following embodiment. Not something. (Embodiment 1) FIG. 1 is an explanatory view of Embodiment 1 of a toner image density detecting apparatus according to the present invention, and FIG. 1A is a view showing a state where a shutter is at a reference light detecting position for detecting diffused plate reflected light. 1B
FIG. 5 is a diagram illustrating a state in which the shutter has moved to a toner image reflected light detection position for detecting reflected light from a toner image for density detection formed on the toner image holding surface. FIG. 2 is a diagram showing a position of a shutter driving member used in the first embodiment. FIG.
3A is a sectional view taken along the line III-III in FIG. 2, FIG. 3A is a view showing a state where the shutter has moved to the reference light detection position shown in FIG. 1A (a sectional view taken along the line IIIA-IIIA in FIG. 1A), and FIG. FIG. 3B is a diagram (a cross-sectional view taken along the line IIIB-IIIB in FIG. 1B) illustrating a state where the toner image has been moved to the toner image reflected light detection position illustrated in FIG. 1B.

1 to 3, a toner image bearing surface S of a toner image bearing member (including a photosensitive member, an intermediate transfer drum, an intermediate transfer belt, a transfer material transport drum, a transfer material transport belt, etc.)
The toner image density detecting device U is used to detect the density of the toner image Tn for density measurement formed on the image forming apparatus. The toner image density detection device U has a detection element support member K. The detection element support member K has a support member main body K1 and an optical path forming member K2 joined to one end surface thereof. The supporting member body K1 includes a light emitting element housing 1 for diffuse reflection light detection, a light emitting element housing 2 for specular reflection light detection, a light receiving element housing 3, a diffusion plate reflected light amount adjusting member housing 4, a shutter housing 5, An emission optical path 6 for regular reflection light detection, an optical path 7 for toner image reflection light incidence, and a diffusion plate reflection light path 8 are formed.

The light path forming member K2 includes a diffused reflected light detection output light path 11, a diffuser plate incident light path 12, a diffuser plate housing 1
3, a spring accommodating portion 14, a regular reflection light detection emission light path 15, a toner image reflection light incidence light path 16, and a dustproof member mounting portion 17 are formed. A diffusion plate 18 is provided in the diffusion plate housing 13.
A dust-proof transparent member (dust-proof member) 19 is bonded to the dust-proof member mounting portion 17. The dust-proof transparent member 28 includes the diffused light detection output light path 11,
Dust is prevented from entering the regular reflection light detection output optical path 15 and the toner image reflected light incident optical path 16.

The light emitting element for diffused light detection 21 is accommodated in the light emitting element housing for diffused and reflected light detection 1, and the light emitting element 22 for specularly reflected light detection is accommodated in the light emitting element for specularly reflected light accommodation 2. The light receiving element 23 is housed in the light receiving element housing 3. The toner image irradiation light L1, which is a part of the light emitted from the diffused light detection light emitting element 21, enters the toner image Tn through the diffused and reflected light detection emission optical path 11, and is diffusely reflected by the toner image. The diffuse reflection light L2 from the toner image Tn passes through the toner image reflection light incident optical path (16 + 7), and
3 is incident. That is, the light receiving element 23 is disposed at a position (a position where no regular reflection light is incident) where the diffuse reflection light L2 of the toner image irradiation light L1 emitted from the diffused light detection light emitting element 21 and incident on the toner image Tn is detected. Have been.

The diffusing plate incident light L3, which is another part of the light emitted from the diffused light detecting light emitting element 21, is the diffusing plate incident optical path 1.
2 and enters the diffusion plate 18. The diffused plate reflected light L <b> 4 diffused and reflected by the diffuser 18 is incident on the light receiving element 23 through the diffused plate reflected light path 8. The diffused light detecting light emitting element 21
Is used when detecting toner image densities of Y (yellow), M (magenta), and C (cyan). As the toner image density increases, the amount of diffuse reflection from the toner image detected by the light receiving element increases. More.

The light-reflection-light-adjusting member housing section 4 for the diffuser plate contains a light-adjustment member 24 having a rectangular cross section so as to be vertically movable and non-rotatable about the vertical axis. A screw hole is formed on the lower surface of the light amount adjusting member 24, and a male screw at the upper end of the operation member 25 is screwed into the screw hole. The operating portion 25a at the lower end of the operating member 25 is
1 protrudes from the lower surface. The lower surface of the light amount adjusting member 24 is constantly urged upward by a compression spring 26, and the vertical position of the light amount adjusting member 24 is positioned at a position where the upper surface of the operation portion 25a contacts the lower surface of the support member main body K1. . The vertical position of the light amount adjusting member 24 can be adjusted by rotating the operation member 25. By adjusting the vertical position of the light amount adjusting member 24, the light amount of the diffused plate incident light L3 emitted from the diffused light detecting light emitting element 21 and incident on the diffuser plate 18 can be adjusted. The amount of the diffused plate reflected light L4 incident on the element 23 can be adjusted. The elements indicated by the reference numerals 24 to 26 constitute a diffuser reflection light amount adjusting device (24 + 25 + 26).

The toner image irradiating light L5 emitted from the regular reflection light detecting light emitting element 22 emits a regular reflection light detecting light path (6 + 1).
5), enters the toner image Tn and is reflected by the toner image. The regular reflection light L6 from the toner image Tn enters the light receiving element 23 through the toner image reflection light incident optical path (16 + 7). That is, the light receiving element 23 is arranged at a position for detecting the regular reflection light L6 of the toner image irradiation light L5 emitted from the regular reflection light detecting light emitting element 22 and incident on the toner image Tn. The light emitting element for regular reflection light detection 22 is used to detect the density of a K (black) toner image. The higher the toner image density, the smaller the amount of regular reflection light from the toner image detected by the light receiving element. . The diffused light detecting light emitting element 2
1 and the light emitting element 22 for regular reflection light detection are switched and used depending on the color of the toner image to be measured.

A shutter 31 is accommodated in the shutter accommodating portion 5, and the shutter 31 is supported rotatably around an axis 32. 1 and 3, a shutter 31 has a diffused plate reflected light passage opening 31a and a toner image reflected light passage opening 3a.
1b, an output light passage 31c for regular reflection light detection and an operated portion 31d (see FIG. 3) are formed. A torsion spring 33 is housed in the spring housing 14. One end 33a of the torsion spring 33 presses the side wall of the shutter housing hole 5, and the other end 33b is bent downward to give a force to rotate the shutter 31 clockwise.

3A and 3B, the support member body K
1, a rotating lever 36 is supported so as to be rotatable around a shaft 36a. A shutter contact portion 36b provided at one end of the rotating lever 36 contacts the side surface of the shutter 31, and a rod connecting portion 36c at the other end is rotatably connected to the tip of the operating rod 37. . The proximal end of the operating rod 37 and the distal end of the telescopic rod 38 a of the solenoid 38 are rotatably connected by a connecting pin 39. Therefore, when the solenoid 38 is turned off, the torsion spring 33 holds the shutter 31 at the position shown in FIGS. 1B and 3B (a toner image reflected light detection position for detecting the toner image reflected lights L2 and L6), and the solenoid 38 is turned on. 1A and 3A (a reference light detection position for detecting the diffused plate reflected light L4).

(Operation of the First Embodiment) In the toner image density detecting device U of the first embodiment having the above configuration, the
1B and FIG. 3B. The state in which the diffuse incident light L4 from the optical path (16 + 7) of the toner image reflected light to the light receiving element 23 can be detected, and the incidence of the diffused plate reflected light L3 to the light receiving element 23 is blocked. State). At this time, a reference reflection sample (for example, a gradation chart: toner area coverage Cin) corresponding to a predetermined toner image density Dx is previously formed on the image bearing surface S.
(Toner occupancy per unit area) from 100% to 0%
And the like, and the diffused light detecting light emitting element 21 is caused to emit light, and each Cinx (x
= 100,90,80, ..., 10,0, Cinx = 10
The received light amount Hux of the light receiving element 23 at 0, 90, 80,..., 10, 0% (x = 100, 90, 80,.
Measure 0). The Cin and the received light amount Hu at the 10% intervals have a predetermined relationship (for example, a function curve),
Further, the toner image density Dx and Cinx (x = 100, 90, 8
Since the relationship of (0,..., 10, 0) has a unique relationship, each toner image density can be obtained from the amount of light received by the light receiving element 23 at each Cinx. However, since the absolute value of the received light amount is affected by the environment and the deterioration with time as described above, the present invention performs the correction described below, and outputs the output correction value of the received light amount and the toner image density. Is performed.

Next, the toner image density detecting device U is set so that the shutter 31 is in the state shown in FIGS. 1A, 2 and 3A (only the diffuse incident light L3 is incident on the light receiving element 23). And the light amount Hua of the diffused plate reflected light L4
(Reference diffused light amount) is detected by the light receiving element 23. Here, it is an aspect of the present invention that the value obtained by dividing the above-mentioned received light amount Hux by the reference diffused light amount Hua is used as the output correction value Hx. That is, the output correction value Hx at the time of Cinx (x = 100 to 0) is Hx = Hux / Hua.
H ₁₀₀ = Hu ₁₀₀ / Hua,..., H ₀ = Hu ₀ / Hua.

Next, when the same measurement is performed by a toner image density detecting device U2 different from the toner image density detecting device U, the respective detected values are calculated as a received light amount H2ux (x = 100
０0) and the reference diffused light quantity H2ua, the output correction value H2x (x = 100-0) is H2x = H2ux / H2
ua. In the toner image density detecting device U and the toner image density detecting device U2, a light emitting element 21, a light receiving element 23,
The output correction values Hx and H2x are not the same because there are variations in the mounting positions of the diffusion plate 18 and the like. For this reason, simply calculating the ratio between the amount of received light and the amount of reference diffused light will cause the toner image density to vary among the devices. Therefore, if the output correction value between the two devices can be adjusted to Hx = H2x = the same value, it is possible to suppress variations in toner image density between the devices. Therefore, in the embodiment of the present invention, the diffused plate reflected light amount adjusting device (24 + 25 + 26) is set so that the ratio of the received light amount and the reference diffused light amount in the toner image density detecting device U2 becomes the same as the value of the toner image density detecting device U. Therefore, if the amount of diffuse reflection light (reference diffuse light amount) is changed, it is possible to suppress variations in toner image density between the respective devices.

As described above, each toner area coverage Cinx {x = 100-0 (%)} and the output correction value H
Since x has a predetermined relationship (for example, a function curve), the adjustment of the output correction value between the respective toner image density detecting devices is performed by adjusting the toner area coverage at a certain point (for example, Cin).
If x (x = 80%) is determined and the diffuse reflection light amount / (reference diffusion light amount) is adjusted so that the value becomes constant, the relationship between the output correction value and the toner image density can be kept constant. Become. At this time, since there is less error in the standardization when there is a certain amount of reflected reflected light, Cinx (x ≧ 50
%). Next, in the toner image density detecting device adjusted as described above, the image bearing surface S
Toner image formed on top, for example, Cinx (x = 50%)
Is detected, the reference output correction value Hx (x = 50) of the toner adhesion amount with respect to a predetermined Cinx (x = 50%)
If the measured output correction value HDx (x = 50) is the same value, the toner image density is controlled to a desired value. However, if the reference output correction value Hx (x = 50) differs from the actually measured output correction value HDx (x = 50), it can be said that there is a change (decrease or increase) in density corresponding to the difference value.
That is, in order to fill in this difference, the density parameters (the charging potential of the image carrier, the laser power, the developing bias, the amount of the developing material in the developing container, the toner concentration when a two-component developer is used, etc.) are used as described above. By performing the control, the density of the toner image placed on the image bearing surface S can be controlled to a desired value. The above is a case in which the density of the color toner is controlled using the diffuse reflection light.

Next, when the toner image is K (black), the reflected light does not return from the toner image even when the light emitting element 21 for detecting diffused light is made to emit light. Impossible. Then, the light emitting element 22 for specular reflection light detection
The light receiving element 23 detects the amount of specular reflection reflected by the light emission of the element, and detects the density of the K (black) toner image. In this case, the density parameter (the charging potential of the image carrier, the laser power, the developing bias, the amount of the developer in the developing container, the toner density when using a two-component developer, etc.) is controlled by the detected value. However, here, the standardization of the output value as described in the density detection by the diffused light is not performed. In other words, the image is affected by environmental fluctuations and deterioration due to aging. However, in the case of a K (black) toner image, since it is almost used for characters, compared to the density fluctuation of color toner where color balance is important, This is because it is not a big problem.

That is, when a color image is created, Y
(Yellow), M (magenta), and C (cyan) color toners are combined to create secondary and tertiary colors. A problem such as a difference in color balance between samples or a plurality of image forming apparatuses occurs. However, by adjusting the output correction value (the same value) using a diffuser reflection light amount adjusting device so that the output correction value of the toner image density detecting device becomes a predetermined value as in the present invention, environmental fluctuations and time-dependent changes can be achieved. Density parameters (charge potential of image bearing member, laser power, developing bias, amount of developing material in developing container, toner concentration when using two-component developer, etc.) without being affected by deterioration or differences between apparatuses. ) Control,
It is possible to control the density of the toner image placed on the image bearing surface S to a desired value.

(Embodiment 2) FIG. 4 is an explanatory view of Embodiment 2 of a toner image density detecting apparatus according to the present invention, and corresponds to FIG. 2 of Embodiment 1 described above. FIG. 5 is a top view of the toner image density detecting device according to the second embodiment, FIG. 5A is a diagram viewed from the arrow VA in FIG. 4, and a diagram in which an optical path forming member and a dust-proof transparent member are omitted, and FIG. It is a figure showing the state where the cleaning member moved from the state of 5A. In the description of the second embodiment,
The same reference numerals are given to the components corresponding to the components of the first embodiment, and the detailed description thereof will be omitted. On the upper surface of the detection element support member K having the support member body K1 and the optical path forming member K2, a cleaning member 42 is rotatably supported around an axis 41. The cleaning member 42 includes the dustproof transparent member 1.
9 (see FIG. 4), which is an L-shaped plate member in plan view. A cleaning brush 42a is provided on a lower surface of a portion of the cleaning member 42 facing the dustproof transparent member 19.
Is provided. A long hole 42 is provided at one end of the cleaning member 42.
b is formed, and the long hole 42b is connected to the connecting pin 3 for rotatably connecting the operating rod 37 and the telescopic rod 38a.
9 is rotatably and slidably engaged. Therefore, as can be seen from FIG. 5, the cleaning member 42 rotates around the shaft 41 in conjunction with the movement of the connecting pin 39 when the solenoid 38 is turned on and off.

(Operation of the Second Embodiment) In the second embodiment of the toner image density detecting apparatus having the above-described configuration, the solenoid 38 is used.
5B, the torsion spring 33 holds the shutter 31 and the cleaning member 42 at the position shown in FIG. 5B (a toner image reflected light detection position for detecting the toner image reflected lights L2 and L6), and when the solenoid 38 is turned on, FIG. (A reference light detection position for detecting the diffused plate reflected light L4). Therefore, when the power is turned off normally (when the toner image density detecting device is not used), the state is as shown in FIG.
When the reference light is detected, the solenoid 38 is turned on, and FIG.
State when the reflected light from the toner image is detected.
8 is turned off and the state of FIG. 5B is obtained. Therefore, when the solenoid 38 is turned on and off, the cleaning member 42 rotates around the shaft 41 to wipe off the dust adhered to the surface of the dust-proof transparent member 19, thereby preventing the surface of the dust-proof transparent member 19 from being stained. it can. Therefore, it is possible to prevent a problem that toner, dust, or the like adheres to the dust-proof transparent member 19 and the measured reflected light amount from the toner image changes.

(Embodiment 3) FIG. 6 is an explanatory view of a toner image density detecting apparatus according to Embodiment 3 of the present invention, and FIG.
FIG. 6B is a view corresponding to FIG. 1A, and FIG. 6B is a view corresponding to FIG. 1B. In the description of the third embodiment, components corresponding to the components of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the third embodiment shown in FIG. 6, the regular reflection light detecting light emitting element 22 for detecting the K (black) toner image density shown in FIG. 1 of the first embodiment is omitted. The light-emitting element accommodating section 2 for light, the output optical path (6 + 15) for regular reflection light detection, and the like are omitted. In the third embodiment, the density of the black toner image cannot be detected by the specularly reflected light from the toner image Tn. However, the density of the toner image of each color of Y (yellow), M (magenta), and C (cyan) is determined. Detection can be performed in the same manner as in the first embodiment.

(Embodiment 4) FIG. 7 is an explanatory view of a toner image density detecting apparatus according to Embodiment 4 of the present invention, and FIG.
7A is a view corresponding to FIG. 6A, and FIG. 7B is a view corresponding to FIG. 6B. In the description of the fourth embodiment, the same reference numerals are given to the components corresponding to the components of the third embodiment, and the detailed description is omitted. In the fourth embodiment shown in FIG. 7, the diffuser reflected light amount adjusting device (24 + 25 + 26) shown in FIG. 6 of the third embodiment is omitted, and accordingly, the diffused plate reflected light amount adjusting member accommodating section 4 and the like are omitted. I have. In the fourth embodiment, the amount of the diffuser incident light L3 emitted from the diffused light detecting light emitting element 21 and incident on the diffuser plate 18 cannot be adjusted. The amount of light L4 cannot be adjusted.
In other respects, the fourth embodiment is the same as the third embodiment.

In the fourth embodiment, since there is no mechanism for adjusting the amount of reflected light from the diffuser plate, the detection accuracy is lower than in the first to third embodiments. Since the configuration is relatively simple, it is suitable for an image forming apparatus that aims at lower cost than image quality.

(Embodiment 5) FIG. 8 is an explanatory view of Embodiment 5 of the toner image density detecting apparatus of the present invention, and FIG.
FIG. 8B is a view corresponding to FIG. 7A, and FIG. 8B is an explanatory view of a device for adjusting the mounting angle of the diffusion plate shown in FIG. 8A. In the description of the fifth embodiment, components corresponding to the components of the fourth embodiment are denoted by the same reference numerals, and a detailed description thereof will be omitted. The fifth embodiment shown in FIG. 8 is different from the fourth embodiment shown in FIG. 7 in that a device for adjusting the angle of the diffusion plate 18 is provided. 8, the diffusion plate 18 is fixed to a rotation shaft 43 rotatably supported by an optical path forming member K2, and the outer end of the rotation shaft 43 is connected to the optical path forming member K2.
Protruding from the outer surface of the. The angle of the diffusion plate 18 is adjusted by rotating the knob 44 attached to the outer end of the rotation shaft 43. A fixing screw through hole 44a is formed in the knob 44, and a fixing screw penetrating the fixing screw through hole 44a with play is screwed into a screw hole formed on the outer surface of the optical path forming member K2. The angle of the diffusion plate 18 can be fixed. In this embodiment,
The amount of the diffused plate reflected light L4 incident on the light receiving element 23 can be adjusted by the elements indicated by the reference numerals 43 and 44 and a fixing screw (not shown). That is, the diffused plate reflected light amount adjusting device (43 + 44) of the fifth embodiment is constituted by the elements indicated by the reference numerals 43 and 44 and the like.

(Embodiment 6) FIG. 9 is an explanatory view of Embodiment 6 of the toner image density detecting device of the present invention, and FIG. 9A is Embodiment 5 of the present invention.
FIG. 9B is an enlarged view of a mounting portion of the diffusion plate shown in FIG. 9A, and FIG. 9C is a perspective view of an apparatus for adjusting the angle of the diffusion plate. In the description of the sixth embodiment, the same reference numerals are given to the components corresponding to the components of the fifth embodiment, and the detailed description thereof will be omitted. FIG.
Embodiment 6 shown in FIG. 8 is different from Embodiment 5 shown in FIG. 8 in which an angle is adjusted in that a device for adjusting the position of the diffusion plate 18 is provided.

In FIG. 9, a prismatic vertical moving block 46 to which the diffusion plate 18 is fixed is supported by a guide groove formed in the optical path forming member K2 so as to be vertically movable and non-rotatably about the vertical axis. The operation screw 47 is screwed into a screw hole of the vertical movement block 46 and vertically penetrates. The operation screw 47 is a support member 48 fixed to the upper surface of the optical path forming member K2.
And an operation portion 47a is provided at an upper end portion. The operation screw 47 is rotatably supported by the optical path forming member K2, and the E-clip 4 accommodated in the E-clip mounting groove 48a formed on the lower surface of the support member 48.
9 regulates upward movement. Therefore,
By rotating the operation part 47a of the operation screw 47, the vertical position of the vertical movement block 46 and the diffusion plate 18 can be adjusted. As a result, the amount of the diffusion plate reflected light L4 incident on the light receiving element 23 can be reduced. Can be adjusted. That is, the elements indicated by the reference numerals 46 to 49 and the like constitute the diffuser reflection light amount adjusting device (46 to 49) of the sixth embodiment. In other respects, the sixth embodiment is the same as the fifth embodiment.

(Embodiment 7) FIG. 10 is an explanatory view of a toner image density detecting apparatus according to Embodiment 7 of the present invention. FIG. 10A is a view corresponding to FIG. 7A of Embodiment 4 and FIG. FIG. 10C is an enlarged perspective view of the mounting portion of the diffuser plate showing the state where the optical path forming member is turned upside down, and FIG. 10C is an explanatory diagram of a method of mounting and fixing the diffuser plate in the guide groove shown in FIG. 10B. In the description of the seventh embodiment, the fourth embodiment will be described.
The same reference numerals are given to constituent elements corresponding to the above-mentioned constituent elements, and detailed description thereof will be omitted. As described in the first embodiment, in the first to fourth embodiments, the diffusion plate 18 is fixed to the diffusion plate accommodating portion 13 of the optical path forming member K2 with an adhesive, whereas the seventh embodiment shown in FIG. In a state where the optical path forming member K2 is separated from the support member main body K1, the diffusion plate 18 can be detachably attached to the optical path forming member K2. FIG.
0B, a guide groove 13 for guiding a pair of outer edges of the diffusion plate 18 is provided in the diffusion plate housing portion 13 of the optical path forming member K2.
a is formed. Further, the diffusion plate 18 is formed with a protruding portion 18a that comes into pressure contact with the guide surface of the guide groove 13a when inserted into the guide groove 13a. Example 7
In this case, since the diffusion plate 18 is detachable from the optical path forming member K2 in a state where the optical path forming member K2 is separated from the support member main body K1, when an inappropriate diffusion plate 18 is mounted,
Replace with an appropriate diffusion plate 18 and mount it. That is, several types of diffuser plates having different diffuse reflectances are prepared, and a diffuser plate having an appropriate diffuse reflectance is selected and mounted.

(Embodiment 8) FIG. 11 is an explanatory view of Embodiment 8 of the toner image density detecting device of the present invention. FIG. 11A is a view corresponding to FIG. 1A of Embodiment 1 and FIG. It is a corresponding figure. In the description of the eighth embodiment,
The same reference numerals are given to the components corresponding to the components of the first embodiment, and the detailed description thereof will be omitted. In the eighth embodiment shown in FIG. 11, the mounting position of the diffusion plate 18 is different from the mounting position of the diffusion plate 18 shown in FIG. 1 of the first embodiment. The arrangement of the housing section 5, the toner image reflected light incident optical path 7, the diffuser reflected light path 8, the diffuser incident light path 12, the diffusion plate housing section 13 and the like is slightly different. The free end of the rotatable shutter 31 has a side wall 31e extending downward,
The diffused plate reflected light passage opening 31a is formed in the side wall portion 31e. Example 8 is different from Example 1 in that
The diffusing plate 18, the diffusely reflected light emitting element 21, and the light receiving element are arranged so that the light receiving element 23 does not include the specular reflected light in the reflected light from the diffusing plate 18 when detecting the reference light.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-mentioned embodiments, but falls within the scope of the present invention described in the appended claims. Thus, various changes can be made. Modified embodiments of the present invention will be exemplified below. (H01) In each of the above embodiments, the case where the amount of light incident on the diffusion plate is adjusted has been described. However, a member for adjusting the amount of light reflected from the diffusion plate can be provided. It is possible to provide a member for adjusting the amount of light applied to the toner image).

[0067]

The above-described toner image density detecting device of the present invention has the following effects (E01) to (E03). (E01) It is possible to provide a toner image density detecting device that is hardly affected by environmental changes such as temperature and humidity and changes over time. (E02) Variations in the detection values of the respective toner image density detecting devices when the densities of the toner images having the same density are detected can be reduced. (E03) Diffuse reflected light amount H of toner image when a plurality of toner image density detecting devices detect the density of toner images of the same density
A value H (= H1 / H) obtained by dividing 1 by a reference light amount H0 for correction.
0) can be the same value for each toner image density detecting device.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first embodiment of a toner image density detecting apparatus according to the present invention, and FIG. 1A is a view showing a state where a shutter is at a reference light detecting position for detecting diffused plate reflected light; FIG. 5 is a diagram illustrating a state in which the shutter has moved to a toner image reflected light detection position for detecting reflected light from a toner image for density detection formed on the toner image holding surface.

FIG. 2 is a diagram illustrating a position of a shutter driving member used in the first embodiment.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;
FIG. 3A shows a state in which the shutter has moved to the reference light detection position shown in FIG. 1A (a cross-sectional view taken along the line IIIA-IIIA in FIG. 1A), and FIG.
FIG. 3B is a diagram illustrating a state where the shutter has moved to the toner image reflected light detection position illustrated in FIG. 1B (a cross-sectional view taken along line IIIB-IIIB in FIG. 1B).

FIG. 4 is an explanatory diagram of a toner image density detecting device according to a second embodiment of the present invention, and corresponds to FIG. 2 of the first embodiment.

5 is a top view of the toner image density detecting device according to the second embodiment, FIG. 5A is a diagram viewed from the arrow VA in FIG. 4, and a diagram omitting an optical path forming member and a dust-proof transparent member; FIG. 5B is a diagram showing a state in which the cleaning member has moved from the state of FIG. 5A.

6 is an explanatory view of a toner image density detecting device according to a third embodiment of the present invention. FIG. 6A is a diagram corresponding to FIG. 1A of the first embodiment, and FIG. 6B is a diagram corresponding to FIG. 1B. is there.

7 is an explanatory diagram of a toner image density detecting device according to a fourth embodiment of the present invention. FIG. 7A is a diagram corresponding to FIG. 6A of the third embodiment, and FIG. 7B is a diagram corresponding to FIG. 6B. is there.

8 is an explanatory view of Embodiment 5 of the toner image density detecting device of the present invention. FIG. 8A is a view corresponding to FIG. 7A of Embodiment 4, and FIG. 8B is a view of the diffusion plate shown in FIG. 8A. It is explanatory drawing of the apparatus which adjusts a mounting angle.

9 is an explanatory view of Embodiment 6 of the toner image density detecting device of the present invention. FIG. 9A is a view corresponding to FIG. 8A of Embodiment 5, and FIG. 9B is a view of the diffusion plate shown in FIG. 9A. FIG. 9C is an enlarged view of a mounting portion, and FIG. 9C is a perspective view of a device for adjusting the angle of the diffusion plate.

FIG. 10 is an explanatory view of Embodiment 7 of the toner image density detecting device of the present invention, and FIG. 10A is FIG. 7A of Embodiment 4;
10B is an enlarged perspective view of the mounting portion of the diffusion plate shown in FIG. 10A, showing the optical path forming member turned upside down. FIG. 10C is a diagram in which the diffusion plate is mounted in the guide groove shown in FIG. 10B. FIG. 4 is an explanatory view of a method for fixing the electronic component.

11 is an explanatory view of Embodiment 8 of the toner image density detecting device of the present invention, and FIG. 11A is FIG. 1A of Embodiment 1;
11B is a view corresponding to FIG. 1B.

FIG. 12 is an explanatory view of a conventional example of a toner image density detecting device for detecting the density of the toner image. FIG. 12A shows diffused reflected light from a toner image for density detection formed on a toner image carrying surface. FIG. 12B is a diagram illustrating a state in which the amount of diffusely reflected light from a toner image bearing surface on which a toner image is not formed is detected.

FIG. 13 is an explanatory view of a conventional example of a toner image density detecting device for detecting the density of the toner image. FIG. 13A shows diffuse reflection light from a toner image for density detection formed on a toner image carrying surface. FIG. 13B is a diagram illustrating a state in which the amount of diffuse reflection from a toner image carrying surface on which a toner image is not formed and the amount of diffuse light reflected by a diffuse reflection plate are detected.

FIG. 14 is a diagram illustrating the toner adhesion amount (toner density) and the output value (detected diffusion light amount) of a sensor (toner image density detector).
It is a graph showing the relationship with.

[Explanation of symbols]

Reference numeral 2 denotes a light-emitting element accommodating section, 3 denotes a light-receiving element accommodating section, 8 denotes a diffused plate reflection optical path, 12 denotes a diffusing plate incident optical path, 13 denotes a diffusing plate accommodating section, 18 denotes a diffusing plate, and 19 denotes a dustproof member (a transparent member for dustproofing). 21 light emitting element, 22 light emitting element for specular reflection light detection, 23 light receiving element, 31 shutter, 42 cleaning member, (24 + 25 + 26) diffusion light amount adjusting device
K: detection element support member, L6: toner image regular reflection light, Tn
... Toner image, U: Toner image density detecting device.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toru Yoshida 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Naoya Yamazaki 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. 2G057 AA01 AB01 AC06 BA01 BB01 DA04 DB01 DC01 JA20 JB01 2G059 AA02 BB09 BB10 EE02 EE11 GG01 HH02 JJ23 KK01 MM05 MM14 NN02 NN07 2H027 DA10 DE02 EA01 EA02 EA05 EA06 EC03 EC14 HA14

Claims (6)

[Claims] 1. A toner image density detecting device having the following requirements (A01) to (A06): (A01) a diffuser for diffusing and reflecting incident light; and (A02) a diffused light detection for the diffuser and the toner image. (A03) a light-receiving element for receiving light emitted from the light-emitting element and diffusely reflected by the toner image or the diffusion plate; and (A04) a diffusion plate housing portion for housing the diffusion plate. A light-emitting element housing part that houses the light-emitting element, a light-receiving element housing part that houses the light-receiving element, and a diffusion plate incident optical path and a diffusion plate that allow a part of light emitted from the light-emitting element to enter the diffusion plate. A diffuser-incident / reflected light path having a diffuser-reflected light path for causing the reflected light to enter the light-receiving element; and a toner-image-irradiating light output for emitting another part of the light emitted from the light-emitting element toward an external toner image. Diffuse in the light path and the toner image A detection element support member having a toner image diffuse reflected light incident optical path for causing the reflected toner image diffuse reflected light to enter the light receiving element; and (A05) a toner image diffuse reflected light incident optical path and a toner image irradiating light exit optical path. A transparent dustproof member provided at an end, (A06) a diffuser reflection light amount adjusting device for adjusting a diffuser reflection light amount, which is an amount of light emitted from the light emitting element, reflected by the diffusion plate, and then incident on the light receiving element; . 2. The toner image density detecting device according to claim 1, which satisfies the following requirement (A07): (A07) The light beam is allowed to pass through by connecting the reflection light path entering and exiting the diffusion plate, and the toner image is detected. A shutter movable between a reference light detection position for blocking the diffused light incident light path and a toner image reflected light detection position for blocking the diffused light incident light path and communicating the toner image diffuse reflected light incident light path. 3. The toner image density detecting device according to claim 1, wherein the following requirements (A08) to (A011) are provided: (A08) Light for regular reflection light detection is applied to the toner image. (A09) a regular-reflection-light-detecting light-emitting-element housing for accommodating the regular-reflection-light-detecting light-emitting element; The detection element support having an emission optical path for specular reflection light emitted toward the toner image, and a toner image regular reflection light incident optical path for causing the toner image regular reflection light that is regularly reflected by the toner image to enter the light receiving element. Member, (A010) a transparent dustproof member provided at the outer end of the regular reflection light detection output light path and the toner image regular reflection light incidence light path, and (A011) the toner image diffuse reflection light incidence light path. The detection device having the toner image regular reflection light incident optical path. Output element support member. 4. A toner image density detecting device according to claim 2, which satisfies the following requirement (A012): (A012) A shutter drive for driving the shutter between a reference light detecting position and a toner image reflected light detecting position. apparatus. 5. The toner image density detecting device according to claim 1, which satisfies the following requirement (A013):
3) the light emitting element disposed at a position where the diffused plate reflected light that is emitted from the light emitting element, reflected by the diffuser plate, and then incident on the light receiving element is only diffusely reflected light that does not include specularly reflected light; A diffusion plate and the light receiving element. 6. The following requirements (A01) to (A05), (A07)
(A01) a diffuser plate for diffusing and reflecting incident light; (A02) a light emitting element for irradiating the diffuser plate and the toner image with light for diffuse reflection light detection; and (A03) a light emitting element. A light-receiving element for receiving light emitted from the toner and diffusely reflected by the toner image or the diffusion plate; (A04) a diffusion plate housing for housing the diffusion plate; a light-emitting element housing for housing the light-emitting element; A light-receiving element housing portion for housing an element, a light-diffusion plate reflection light path for making a part of the light emitted from the light-emitting element incident on the light-diffusion plate and a light-diffusion plate reflection light path for making the light reflected by the light-diffusion plate incident on the light-receiving element; A diffuser plate entering / reflecting optical path, a toner image irradiation light emitting optical path for emitting another part of light emitted from the light emitting element toward an external toner image, and a toner image diffuse reflection reflected by the toner image Receive the light (A05) a transparent dustproof member provided at an outer end of the toner image diffuse reflection light incident optical path and the toner image irradiation light emission optical path; (A07) A reference light detection position for blocking the incident light path of the toner image diffuse reflection light, and a reference light detection position for cutting off the light path incident to the diffusion plate, and the toner A shutter movable between a toner image reflected light detection position for communicating the image diffuse reflected light incident optical path;