JPH0980892A - Developing device - Google Patents

Abstract

(57) Abstract: A developing device is provided which does not cause a decrease in detection accuracy due to an increase in the diameter of a container, etc., even though a photo sensor is used as a means for detecting the amount of toner remaining in the toner container. To do. A developing device including a toner tank for containing toner, a toner hopper equipped in the toner tank for replenishing the toner in the toner tank, and a stirring / conveying member rotated by a shaft arranged inside the toner hopper. In the toner hopper, a transparent window for exposing the inside of the hopper is provided, and the stirring / conveying member has a reflecting plate facing the transparent window when passing through the transparent window, and a transparent plate when passing through the transparent window. A transparent window cleaning member for slidingly contacting and cleaning the inner surface of the transparent window is provided, and a reflective photo film is provided at a position outside the transparent window and facing the reflection plate through the transparent window. The sensor is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a developing device for an electrophotographic image forming apparatus, and more particularly to a developing device having a detecting means for detecting the amount of toner remaining in a toner container constituting the developing device by a photo sensor. In regard to the above, it relates to a developing device capable of significantly reducing the occurrence rate of false detection.

[0002]

2. Description of the Related Art In an image forming apparatus utilizing an electrophotographic process such as a copying machine, a printer and a facsimile machine, an electrostatic charge is generated by irradiating a photosensitive member which is uniformly charged in advance with reflected light of a document. After forming a latent image and developing this electrostatic latent image with toner supplied from the developing device,
This toner image is transferred and fixed on the transfer paper. In the developing device, a developing roller, an agitator, etc. are arranged in the toner tank, and a toner replenishing portion is arranged in contact with the toner tank. A toner container containing toner is detachably attached to the toner replenishing unit, and is controlled so that a required amount of toner is replenished from the replenishing unit to the toner tank when the toner in the toner tank is reduced. . By the way, as a remaining amount detecting means for detecting the remaining amount of toner in the toner container or the presence / absence of toner, transparent windows are respectively provided on two opposing side walls of the container, and a light emitting element is provided outside one of the transparent windows. It is known that the detection light is transmitted through the inside of the container by disposing light receiving elements outside the other window. And the amount of detected light is
The presence or absence of the toner is detected depending on the presence or absence of the detected light amount (JP-A-1-316765, JP-A-2-85451, and JP-A-63-2087).

[0003]

However, in the conventional detection method using the transmissive photosensor, since the detection light is transmitted through the inside of the toner container, the optical path becomes longer as the diameter of the container becomes larger. Therefore, the amount of light received by the light receiving element decreases,
As a result, erroneous detection is likely to occur even if the transparent window is slightly soiled. The erroneous detection causes an erroneous notification of the replacement time of the toner container, resulting in a problem that copying is possible despite the toner end. The present invention has been made in view of the above, and does not cause a decrease in detection accuracy due to an increase in the diameter of a container or the like, even though a photo sensor is used as a means for detecting the amount of toner remaining in the toner container. It is intended to provide a developing device.

[0004]

In order to achieve the above object, the invention according to claim 1 is a toner tank for containing toner, a toner hopper equipped in the toner tank for replenishing the toner in the toner tank, and a toner hopper. In a developing device having an agitating / conveying member rotated by a shaft arranged inside, a transparent window for exposing the inside of the hopper is provided in the toner hopper, and the agitating / conveying member passes through the transparent window. A transparent plate for facing the transparent window and a transparent window cleaning member for slidingly contacting the inner surface of the transparent window to clean it when passing through the transparent window. A reflection type photo sensor is arranged at a position where it can face the reflection plate through the transparent window.

According to the developing device of the first aspect, since the toner remaining amount detecting means including the reflection type photo sensor is used and the reflecting plate passing near the transparent window is detected, the optical path of the detection light is shortened. Since the reduction of the light quantity is prevented, it is possible to prevent erroneous detection.

The invention of claim 2 is characterized in that the reflecting surface of the reflecting plate is white. According to the present invention, since the white plate is used as the reflection plate, the amount of reflected light increases and the effect of preventing erroneous detection is enhanced. The invention of claim 3 is characterized in that a detecting means for detecting a position where the reflection plate faces the reflection type photo sensor is provided. According to the present invention, since the position where the reflection plate faces the photo sensor can be detected, it is not necessary to constantly detect the presence or absence of the developer or toner, and it is only necessary to detect when the reflection plate reaches the position facing the optical sensor. Good. Therefore, the load required for controlling the device is reduced and at the same time the detection accuracy is improved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 is a cross-sectional view of an example of a developing device to which the present invention is applied. A developing device 2 is arranged at a side position of a photoconductor drum 1, and a toner hopper 5 of the developing device detects a remaining toner amount of the present invention. The device is located. Although the developing device 2 is a two-component developing device, the present invention can be applied to a developing device using a one-component developer. In FIG. 1, the photosensitive drum 1 is uniformly charged by a charger (not shown) to form an electrostatic latent image by exposure from an exposing means (not shown), and the electrostatic latent image is developed by a developing sleeve of the developing device 2. The toner image is developed with toner supplied from No. 3, and the toner image is transferred onto a transfer paper by a transfer device (not shown). The developing device 2 has a toner tank 4, a toner hopper (toner container) 5 connected to the toner tank, a replenishing roller 6 arranged at the boundary between the toner tank and the toner hopper, and the like. The toner hopper 5 has a cylindrical shape, and one end of the stirring / conveying member 8 is fixed to the shaft 7 of the toner hopper 5, and the other end of the stirring / conveying member 8 is substantially L-shaped (a surface facing the inner wall of the toner hopper 5). A reflector 9 is formed on the. The shaft 7 is rotationally driven by a drive source (not shown). Further, one end of a cleaning member 10 made of an elastic plate material is fixed to the other end of the stirring / conveying member 8 at a proper position, and the other end of the cleaning member 10 is configured to be in sliding contact with the inner wall of the toner hopper 5. When the shaft 7 rotates in the direction of the arrow, the cleaning member 10 slides on the inner wall of the toner hopper to scrape off the toner T adhering to the inner wall, and also supplies the toner toward the replenishing roller 6. A reflecting plate cleaning member 11 has one end protruding at an appropriate position on the inner wall of the toner hopper 5, and every time the reflecting plate 9 passes, the tip of the cleaning member 11 slides on the surface of the reflecting plate 9 and adheres to the toner. Acts to remove. The cleaning member 11 is also made of an elastic plate material such as resin. Further, an opening 12 is formed at a proper position (preferably the lower surface) of the toner hopper 5, and a transparent window 14 is formed by closing the opening 12 with a transparent plate 13, and a light emitting element 15a is provided outside the transparent window 14. A reflection type photo sensor 15 (toner remaining amount detecting means) including a light receiving element 15b is arranged opposite to each other. The photo sensor 15 sets the direction and the like so that it can detect the reflection plate 9 passing through the transparent window 14.

As the material of the cleaning members 10 and 11, rubber or resin having a large elasticity (polyethylene or the like) is used. With respect to the transparent window 14, the cleaning member 10 has a role of removing the toner adhering to the inner surface thereof, and by removing the adhering toner, the detection accuracy of the reflection plate 9 can be improved. Further, since the photo sensor 15 and the reflection plate 9 are extremely close to each other, the optical path length of the detection light can be short, and the false detection rate due to a slight amount of toner adhering to the transparent window is significantly reduced. Further, the reflection plate cleaning member 11 removes the toner adhering to the surface of the reflection plate 9 so that the reflectance can always be kept high and erroneous detection can be prevented. By making the reflecting surface of the reflecting plate white, for example, the detection accuracy can be further improved.

In the above-described structure, the toner remains in the transparent window even after the cleaning member 10 passes through the transparent window 14 until the state before the toner amount in the toner hopper 5 is almost exhausted (near end). Exists, so light-emitting element 1
When the light receiving element 15b receives the detection light emitted from the light source 5a, the amount of the light becomes less than a specified value. Therefore, a control unit (microcomputer) not shown determines that toner is present. When the toner in the toner hopper 5 reaches a state where there is no toner (end) or there is almost no toner (near end), the cleaning member 10 passes through the transparent window 14 and no toner remains in the transparent window portion, so that the light is emitted from the light emitting element 15a. The detected light is directly applied to the reflector 9. When the reflection plate 9 reaches the transparent window in a state where the toner on the surface is removed by the reflection plate cleaning member 11, the detection light is reflected by the reflection plate 9 (which has a higher reflectance than the toner, such as white). As a result, the light receiving element 15b receives more light than the specified amount, and the control unit (not shown) determines that there is no toner. This detection accuracy is extremely high.

Next, FIG. 2 is a perspective view of an essential part of another embodiment (a modified embodiment of FIG. 1) of the present invention, in which a shield plate 20 is integrated at an appropriate position of the shaft 7, for example, at an end thereof. , Shield plate 20
By arranging the photo interrupter 21 in the rotation path of the end portion 20a, the timing at which the reflection plate 9 reaches the position facing the transparent window 14 (photo sensor 15) is detected. That is, the positional relationship between the end 20a of the reflection plate 9 and the photo interrupter 21 and the angle thereof are predetermined so that the timing at which the end 20a shields the photo interrupter 21 coincides with the transparent window passage timing of the reflection plate 9. With the above configuration, the above detection operation can be realized. In this way, the timing at which the reflection plate 9 passes through the transparent window 14 is detected. If the presence or absence of toner is constantly detected by the reflection type photosensor 15, the control program and control signals increase unnecessarily, and the cost increases due to complication. This is to prevent the inconvenience of the above, and by performing detection only while the reflection plate passes through the transparent window, it is possible to simplify the configuration of the control unit side and the operation, and as a result, the detection accuracy is improved. It is possible to raise it. In the present invention, the toner hopper is a concept that includes not only a hopper connected to the toner tank 4 but also a toner container that is attached to and detached from a toner replenishing section.

[0011]

As described above, according to the invention of claim 1,
Since the reflection plate 9, the reflection plate cleaning member 11 and the transparent window cleaning member are provided and the reflection type photo sensor is arranged outside the transparent window, the optical path is short when the presence or absence of toner in the toner hopper is detected by the detection light. Therefore, the reflected light from the reflector can be accurately detected, and false detection can be significantly reduced. In the developing device according to the second aspect, since the white plate is used as the reflecting plate 9, it is possible to efficiently reflect the detection light from the reflective photosensor, improve the detection accuracy, and reduce the false detection. According to the third aspect of the invention, the position where the reflection plate passes through the transparent window is detected, and the presence or absence of toner is detected only when the reflection plate comes to the position facing the reflection type photo sensor.
It is possible to significantly reduce the load associated with the control of the apparatus and improve the accuracy of detecting the presence or absence of toner.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of a developing device to which the present invention is applied.

FIG. 2 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

[Explanation of symbols]

1 photoconductor drum, 2 developing device, 3 developing sleeve,
4 toner tank, 5 toner hopper (toner container), 6
Replenishing roller, 7 axis, 8 stirring / conveying member, 10 transparent window cleaning member, 11 reflecting plate cleaning member, 12 opening, 1
3 transparent plate, 14 transparent window, 15 reflection type photo sensor (toner remaining amount detecting means)

Claims (3)

[Claims] 1. A developing device comprising: a toner tank for containing toner; a toner hopper provided in the toner tank for replenishing the toner in the toner tank; and an agitating / conveying member rotated by a shaft arranged in the toner hopper. In the apparatus, the toner hopper is provided with a transparent window for exposing the inside of the hopper, and the stirring / conveying member has a reflection plate facing the transparent window when passing through the transparent window, and a transparent plate when passing through the transparent window. Is provided with a transparent window cleaning member for slidingly contacting the inner surface of the transparent window to clean it, and at a position outside the transparent window and facing the reflection plate through the transparent window, a reflection type A developing device in which a photo sensor is arranged. 2. The developing device according to claim 1, wherein the reflecting surface of the reflecting plate is white. 3. The developing device according to claim 1, further comprising detection means for detecting a position where the reflection plate faces the reflection type photo sensor.