JPH0756431A - Remaining-toner amount detector for developing device - Google Patents

Abstract

PURPOSE:To accurately detect remaining-toner amount at all times by preventing toner from sticking to the transparent wall of a storage chamber, in the remaining-toner amount detector of an electro-photographic device using the toner. CONSTITUTION:Toner in the storage chamber 59 is stirred to be supplied to a developing chamber from the storage chamber, the toner is carried to an image carrier 40 in the developing chamber, and the presence and absence of toner in the storage chamber 59 is optically detected by transmission type photosensors 90 and 91 via the transparent wall provided in the lower part in the storage chamber 59. In this case, the transparent wall of the storage chamber 59 is cleaned by an elastic member 54b from the inside of the chamber 59.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus using toner, and more particularly, a toner remaining amount of a developing device for developing an electrostatic latent image on an image bearing member with toner by a transmissive photosensor. Regarding a detection device. In image forming apparatuses such as copiers, printers, and facsimile machines, electrophotographic machines and the like are used because of the demand for plain paper recording.
A process is performed in which the photosensitive drum is charged, imagewise exposed to form an electrostatic latent image, developed by a developing device, the toner image is transferred to a sheet, and the toner image is obtained on the sheet.

In such an image forming apparatus, since the toner is conveyed to the photosensitive drum and the toner is developed,
A storage chamber is provided inside the developing device to store toner.
When the toner in the storage chamber is used up, the developing operation is not performed. Therefore, it is necessary to detect the remaining amount of toner in the storage chamber.

[0003]

2. Description of the Related Art FIG. 1 is an illustration of a conventional toner remaining amount detecting device. As shown in FIG. 1A, the developing device 5 is
A storage chamber 59 for storing toner and a developing chamber 58,
In the developing chamber 58, the rotating paddle roller 53 stirs and conveys the toner, and the reset roller 52 conveys the toner to the developing roller 50. The blade 51 regulates the toner layer thickness of the toner on the developing roller 50. Photosensitive drum 40
It is transported to and developed.

On the other hand, the storage chamber 59 is provided with an agitator (paddle roller) 54, which is rotated to agitate the toner and supply it to the developing chamber 58. A transmissive photosensor 90 including a light emitting element and a light receiving element is provided below the storage chamber 59. While the transmissive photosensor 90 is shielded by toner, there is toner and the toner is not shielded. Then, it is determined that there is no toner (toner empty), and toner empty is detected.

To detect the toner empty, the output of the transmissive photosensor 90 is integrated over time, and if the integrated value is greater than or equal to a set value, it is determined that toner is present, and if it is less than or equal to the set value, toner empty is determined. When the toner becomes empty, the developing device itself is replaced and the toner is replenished. As the residual toner amount of this toner empty becomes smaller,
It is economical because the replacement cycle can be extended and the amount of discarded toner can be reduced.

[0006]

However, the prior art has the following problems. If the residual toner amount of the toner empty is set to be small, the fluidity becomes large when the toner amount becomes small. Therefore, as shown in FIGS. The shape of the toner lump at the position immediately before 90 is different, and the transmissive photosensor 90 may or may not be shielded from light, which makes it difficult to accurately detect the remaining toner amount.

Since the transmissive photo sensor 90 is used, if toner adheres to the wall surface of the toner storage chamber,
In reality, even though the amount of toner inside the storage room is empty, the optical path of the sensor is blocked by toner,
It becomes difficult to accurately detect the remaining amount of toner. Regarding the above problems, the applicant of the present application filed a prior application (Japanese Patent Application No. 04-25
No. 7927), a developing device provided with a plurality of transmissive photosensors at different installation positions in the toner storage chamber and a circuit for determining toner empty based on the sum of outputs of the plurality of transmissive photosensors. Toner empty detection device was proposed.

According to the toner empty detecting device having such a structure, it is possible to safely generate an output according to the toner amount regardless of the shape variation of the fluid toner mass and the movement of the toner, and also the scratches and stains are generated. Even if the amount of toner in the toner empty is small, the toner empty can be stably detected by enabling the toner detection with the influence thereof reduced.

However, the above problems have not been solved yet. Therefore, the present invention prevents the toner from adhering to the wall surface of the toner storage chamber and the like, prevents the optical path of the transmissive photosensor from being blocked by the attached toner, and accurately determines the amount of toner remaining in the storage chamber. It is an object of the present invention to provide a toner remaining amount detecting device for a developing device, which is capable of detecting the remaining amount.

Further, in the prior art, the toner is detected without toner (toner empty), so the toner is replaced when the empty is detected. However, the fact that printing cannot be performed immediately after detecting the absence of toner is a problem in the use of the apparatus. For this reason, it is set so that several sheets can be printed even after the toner is not detected. This is for convenience of using the apparatus until the toner is replaced. Conventionally, the remaining amount is relatively large as a toner no notice (toner near empty). The detection was done in my house.

However, in this system, the number of printed sheets varies depending on the toner consumption rate, and regardless of this, the present invention continuously detects (displays) the remaining amount of toner and clearly indicates the toner replacement time. I will provide a.

[0012]

In order to achieve the above-mentioned object, according to claim 1, a storage chamber for storing toner,
A stirring means for stirring the toner in the storage chamber, a means for supplying the stirred toner from the storage chamber to the developing chamber, and conveying the toner to the image carrier in the developing chamber; It comprises a detection means for optically detecting the presence or absence of toner in the storage chamber by at least a pair of light emitting element and light receiving element via the transparent wall, and means for cleaning the transparent wall of the storage chamber from the inside of the storage chamber. A toner remaining amount detecting device for a developing device is provided.

According to a second aspect of the present invention, in the first aspect, the agitator comprises an agitator which rotates about a rotary shaft, the cleaning means comprises an elastic member attached to the agitator, and the elastic member comprises the agitator. It is configured to move while being in contact with the transparent wall by the rotation of. According to a third aspect, in the second aspect, the elastic member is made of a material whose hardness changes with temperature, such as silicon rubber, and a temperature detecting means for detecting the temperature of the elastic member is provided to detect the temperature change. It is characterized in that the change in the continuous time of the transmitted light between the light emitting element and the light receiving element is corrected by the change in the hardness of the elastic member.

According to a fourth aspect, in the second aspect, means for detecting the fluidity of the toner in the storage chamber is provided, and whether or not the toner is a suitable developer is determined based on the detected fluidity of the toner. It is characterized in that a judgment is made.

[0015]

According to the first aspect of the present invention, since the means for cleaning the transparent wall of the storage chamber from the inside of the storage chamber is provided, toner does not adhere to the transparent wall of the storage chamber, and good transparency is always maintained. Since it is maintained, it is possible to accurately detect the remaining toner amount. According to the second aspect, since the elastic member which is the cleaning means is attached to the agitator which is the stirring means, the elastic member is also rotated by the rotation of the agitator to clean the transparent wall.
Therefore, it is not necessary to provide the cleaning means with a special drive source.

According to the third aspect, even when the elastic member made of a material whose hardness changes with temperature change such as silicon rubber is used, the continuous transmission of light between the light emitting element and the light receiving element. It corrects the change in time. Therefore, even if the temperature of the toner storage chamber changes, an error does not occur in the detection of the remaining toner amount, and the remaining toner amount can be always accurately detected.

According to the fourth aspect, since the means for detecting the fluidity of the toner in the storage chamber is provided, it is possible to determine whether the toner used is within the applicable range as the developer. When the toner is within the applicable range, it is possible to properly detect the remaining toner amount. Therefore, by detecting the fluidity of the toner in this manner, it is possible to determine whether or not the remaining toner amount can be properly detected.

[0018]

【Example】

(A) Description of apparatus to which the present invention is applied FIG. 2 is an external view of an image forming apparatus to which the present invention can be applied, FIG. 3 is a sectional view of the image forming apparatus, and FIG. 4 is a process in the image forming apparatus. FIG. 5 is a configuration diagram of a cartridge, FIG. 5 is an explanatory diagram of opening and closing of a cover of the image forming apparatus, and FIG. 6 is an operation explanatory diagram of the image forming apparatus.

FIG. 2 shows a perspective view seen from the front of the apparatus,
Reference numeral 10 denotes a front cover, which is opened to the front to open the transport path 3 which will be described later with reference to FIG. 3, 11 is an upper cover which covers the upper part of the device, which is opened to the upper part to open the upper part of the device, 12 Is a paper feed cassette, and 13 is a paper feed cassette insertion port for inserting the paper feed cassette 12 from the front side of the apparatus.

Reference numeral 14 is a stacker provided on the upper surface of the apparatus,
A printed paper is accommodated, 15 is a paper guide, which guides the paper together with the stacker 14, 16 is an operation panel having various switches and a display unit, 17 is a controller box, and printer It accommodates the control circuit and the like. In the cross-sectional view of the apparatus of FIG. 3, 2 is a process cartridge, which is provided above the paper cassette 12, and which will be described later with reference to FIG. 4, 3 is a transport path, and a U-shaped transport path from the paper cassette 12 is provided. To form a sheet and convey the sheet to the stacker 14, and 6 is a heat fixing device for fixing the toner image of the sheet by sandwiching the sheet between the heat roller 60 and the backup roller 61. The cleaning roller 62 for removing the toner adhered to the heat roller 60 is provided.

Reference numeral 7 denotes an optical unit, which scans the light of a semiconductor laser driven by image information with a polygon mirror, passes over the developing device 5, and passes through the process cartridge 2
Is a sheet separating section, which has a discharge electrode, discharges electric charges having a polarity opposite to that of the sheet back surface potential to the back surface of the sheet after transfer, and removes the back surface of the sheet. Then, the paper is separated from the photosensitive drum 40.

Reference numeral 30 is a pickup roller for picking up the paper in the paper cassette 12, 31 is a registration roller for conveying the paper picked up by the pickup roller 30 with the leading ends aligned, and 32 is a manual feed guide. , Which is opened to the right side of the drawing, guides the manually fed paper to the manual feed roller 33, and 33 is a manual feed roller which conveys the paper inserted from the manual feed guide 32 to the process cartridge 2.

Reference numeral 32 is a cover shaft, and the front cover 1
A discharge roller 36 serves as a rotation shaft of 0, and is for discharging the paper having passed through the thermal fixing device 6 to the stacker 14. In the configuration diagram of the process cartridge of FIG. 4, the process cartridge 2 includes a drum cartridge 4 and a developing device 5. The developing device 5 is attached to the drum cartridge 4 by a pin, and the drum cartridge is removed by removing the pin. Separated from 4.

Explaining the structure of the drum cartridge 4, reference numeral 40 denotes a photosensitive drum, which is formed by forming an organic photosensitive material layer (OPC or the like) on the surface of a cylindrical substrate made of aluminum or the like, and rotates counterclockwise as shown in the drawing. What is done, 41
Is a charging roller, which is composed of a conductive rotary brush charger in which conductive rayon fibers are woven into a core metal and is planted, and uniformly charges the photosensitive drum 40 to about -650V.

A transfer roller 42 is provided on the drum cartridge 4 and is made of a conductive porous sponge material, for example, a porous polyurethane polyurethane sponge material.
The photosensitive drum 40 is pressed against the photosensitive drum 40 and a transfer voltage is applied to transfer the toner image on the photosensitive drum 40 onto a sheet. Reference numeral 43 denotes a waste toner box (cleaner).
The residual toner of 0 is scraped by the scraping blade 44 and accommodated therein, and 45 is a grip, and the drum cartridge 4
And a roller cover 46 for protecting the transfer roller 42.

Next, the structure of the developing device 5 will be described.
Is a developing roller, which is made of a conductive elastic roller, preferably a conductive porous sponge material, for example, a conductive porous polyurethane foam sponge material, and rotates in a clockwise direction as shown in FIG. The component toner is held by its surface holding force and is conveyed to the photosensitive drum 40. The component toner is pressed against the photosensitive drum 40 so as to have a predetermined nip width, and a developing bias voltage of −300 V is applied. is there.

Reference numeral 51 denotes a layer-thickness regulating blade portion, which regulates the layer thickness of the toner adhered to the developing roller 50 to a predetermined thickness, and is composed of a stainless plate having a thickness of 0.1 mm. Is pressed to, for example, negative -400V
When the toner layer thickness is regulated, a negative charge is injected into the toner, and the toner is forcibly charged negatively to stably charge the toner even at high humidity and high temperature.

A reset roller 52 is made of a conductive sponge material, is in contact with the developing roller 50, is rotated in the same direction as the developing roller 50, and is applied with a bias voltage of -400 V. To scrape off the toner from the developing roller 50 and to supply the toner to the developing roller 50 at the left side of the drawing.

Reference numerals 53 and 54 denote paddle rollers, which rotate to agitate the non-magnetic one-component toner in the developing device 5 and convey it toward the reset roller 52. Reference numeral 55 denotes a cassette accommodating portion, which is a toner cassette. 56 is accommodated. Reference numeral 56 denotes a toner cassette (toner replenishing portion), which stores one-component non-magnetic toner and is detachably set in the cassette storing portion 55, and 57 is a toner supply lever, which is provided in the toner cassette 56. Rotating to supply the toner in the toner cassette 56 into the developing device 5, reference numeral 56a is a grip, which is provided on the toner cassette 56 and is used for holding the toner cassette 56 by hand, and 5a is a paper guide rib. That is, together with the roller cover 46, the sheet is guided between the photosensitive drum 40 and the transfer roller 42.

The operation of the printer will be described with reference to FIGS. 2 to 4. The sheets in the sheet cassette 12 are picked up by the pickup roller 30, abutted against the registration roller 31, and aligned at the leading end by the registration roller 31.
The U-shaped conveying path 3 is conveyed toward the photosensitive drum 40. On the other hand, when the paper is picked up by the registration roller 31, the image exposure of the photosensitive drum 40 by the optical unit 7 is started, and the potential of the image exposure portion of the photosensitive drum 40 charged to −650V by the charging roller 41 becomes zero. , An electrostatic latent image corresponding to the image is formed.

In the developing device 5, the developing roller 50 is -40.
Since the bias voltage of 0V is applied, the negatively charged toner adheres to the image-exposed portion of the photosensitive drum 40 where the potential is zero, and a toner image is formed. The toner image on the photosensitive drum 40 is transferred onto the sheet conveyed by the registration roller 31 by the transfer roller 42 by electrostatic force and pressure, and the sheet electrostatically attracted to the photosensitive drum 40 is stored in the sheet separating unit 8. The supplied electric charge removes the electric potential on the back surface of the paper to separate it from the photosensitive drum 40.

The separated sheet is sent to the heat fixing device 6, the toner image on the sheet is heat fixed by the heat roller 60 of the heat fixing device 6, and is discharged to the stacker 14 by the discharge roller 36. Similarly, the paper inserted by tilting the manual feed guide 32 is conveyed toward the photosensitive drum 40 by the manual feed roller 33, and the toner image on the photosensitive drum 40 is transferred by the transfer roller 42 by electrostatic force and pressure, and is exposed. The sheet electrostatically attracted to the drum 40 is separated from the photosensitive drum 40 by the electric charge supplied to the sheet separating unit 8, and the thermal fixing device 6
And the toner image on the paper is sent to the heat roller 60 of the heat fixing device 6.
It is heat-fixed by the stacker 14 by the discharge roller 36.
Is discharged to.

5, the front cover 10 is opened to the front surface on the right side of the drawing around the cover shaft 34, and the front cover 10 has a manual feed guide 32 and a manual feed roller. 33 and the paper separating section 8
The heat fixing device 6 and the discharge (drive) roller 36a on the upper side of the discharge rollers 36 are provided. Further, the upper cover 11 is opened to the upper part of the apparatus in the upper part of the drawing centering on a shaft (not shown), and among the discharge rollers 36, a lower discharge (pinch) roller 36b is provided.

Therefore, as shown in FIG. 6A, when the front cover 10 is opened, the U-shaped conveying path 3 from the registration roller 31 to the discharge roller 36 is opened, which is convenient for removing jammed paper. At this time, since the transfer roller 42 is provided on the process cartridge 2 side, the portion of the photosensitive drum 40 is not opened.
Is provided on the process cartridge 2 side because the transfer operation cannot be performed properly if there is a deviation (parallelism, position) with respect to the photosensitive drum 40. Therefore, even if this portion is not opened, a jam is generated. There is no problem in removing the paper.

Similarly, the reason why the entire heat fixing device 6 is provided on the front cover 10 is that if the heat fixing device 6 is divided so that the conveying path can be opened, a part of the heat fixing device 6 is placed on the process cartridge 2. This is because it has to be installed in the process cartridge 2, which makes it inconvenient to take out the process cartridge 2. Even if this portion is not opened, there is no problem in removing the jammed paper.

In opening the cover, as shown in FIG. 3, the front cover 10 is opened so that the upper cover 11 is not opened unless the front cover 10 is opened.
Is disposed on the upper cover 11 at the discharging portion. Therefore, as shown in FIG. 6B, if the front cover 10 is opened and the upper cover 11 is further opened, as shown in FIG. With the process cartridge 2 installed, the toner cassette 56 can be easily taken out and attached to replace only the toner cassette 56.

Since the front cover 10 opens the front of the apparatus and the upper cover 11 opens the upper section of the apparatus, the process cartridge 2 can be easily taken out and attached, and even if the process cartridge 2 is large, it can be easily replaced. . For this reason, the process cartridge 2 can be made large, and the developing device 5 in the process cartridge 2 can be made large, so that the amount of stored developer can be increased and the replacement cycle can be greatly extended.

Also, by replacing only the toner cassette 56,
Since the developer can be replenished, the exchange period can be further extended. Further, the discharge roller 36 is separated and the cover 1
Since 0 and 11 are opened, the entire U-shaped transport path 3 can be opened, and the jammed paper can be taken out more easily.

(B) Description of Embodiment of the Present Invention FIGS. 7 to 12 show an embodiment in which two pairs of transmissive photosensors are provided, FIG. 7 is a front view of the embodiment, and FIG. 8 is of FIG. 8 is a vertical cross-sectional view taken along line 8-8, FIG. 9 is a horizontal cross-sectional view taken along line 9-9 in FIG. 7, FIG. 10 is a vertical cross-sectional view of the toner storage chamber before the remaining amount detecting unit is attached, and FIG. 11 is the remaining amount detecting unit. Is a vertical sectional view of FIG. 12, and FIG. 12 is a circuit diagram in an embodiment of the present invention.

As shown in FIG. 7, the remaining amount detecting section 9 provided below the storage section 59 is provided with two transmissive photosensors 90 and 91, and the first transmissive photosensor 90 is provided. Is located at a distance L ₁ from the axis in the diameter direction of the agitator 54, and the second transmissive photosensor 91 is
A distance L from the axis in the diameter direction of the agitator 54
It is provided at a position of ₂ (L ₂ <L ₁ ).

As shown in FIG. 11, the remaining amount detecting portion 9 includes a transmissive photosensor on a sensor substrate 95 in a case 92 having a substantially U-shaped cross section urged by a spring 94 to a base 93. Light emitting portions 90a and 91a of 90 and 91 and a light receiving portion 9
0b and 91b are attached, and the light emitting unit 9 is
0a, 91a and the light receiving parts 90b, 91b are configured so as not to become dirty.

On the other hand, as shown in FIG. 10, a pair of transparent sensor accommodating parts 59a and 59b are provided in the lower part of the storage part 59, and an agitator shaft as a stirring means is provided between the sensor accommodating parts 59a and 59b. An elastic member 54b made of silicon rubber or the like attached to 54a passes through. The light emitting portions 90a, 91a of the case 92 and the light receiving portions 90b, 91b are inserted into the sensor housing portions 59a, 59b. The bottom surface of 59b is abutted and positioned, so that even if the developing device 5 is replaced, the pair of photosensors 90 and 91 can be positioned at predetermined positions in the storage portion 59 of the developing device 5. 8 and 9 show a state in which the remaining amount detecting portion 9 is attached to the developing device 5.

Then, the elastic member 54b provided on the agitator shaft 54a sweeps the light emitting window portion and the light receiving window portion of the sensor accommodating portions 59a and 59b according to the rotation of the agitator 54 to remove the adhered toner and stabilize the operation. Toner detection is possible. In FIG. 12, the sensor substrate 95 has a resistor R between + 5V and 0V supplied from the device side.
₁ and a pair of light emitting parts (light emitting diodes) D ₁ and D ₂ (9
0a, 91a) are connected in series and driven, and in parallel with this, a pair of light receiving parts (phototransistors) Q
₁ (90b) and Q ₂ (91b) are connected in parallel, and the adjustment resistors R ₂ and R ₃ are connected in series to this.

Therefore, on the sensor substrate 95, the sum of the outputs of the pair of light receiving portions 90b and 91b is calculated and output. On the other hand, the averaging circuit compares the output of the averaging circuit 96a with the set voltage by receiving the sum of the outputs of the pair of light receiving units 90b and 91b and integrating the outputs over time. A comparator circuit 96b is provided for generating a toner empty signal when the output of 96a becomes equal to or lower than the set voltage.

FIG. 13 is a circuit diagram of another embodiment.
A pair of transmissive photosensors are provided. In this embodiment, a resistor R ₁ and one light emitting portion (light emitting diode) D ₁ (90a) are connected in series between +5 V and 0 V, and one light receiving portion (phototransistor) is connected in parallel with this. ) Q ₁ (90b) and the adjusting resistor R ₂ are connected in series. The other structure is the same as that of FIG. 12, and the output of the light receiving unit 90b is integrated by the averaging circuit 96a,
The comparison circuit 96b compares it with the set voltage.

FIG. 14 is a block diagram of still another embodiment. In the figure, A is a light detecting unit including a light emitting unit and a light receiving unit as described above, B is a timer, C is a control unit, C ₁ is a timer control unit, C ₂ is a duty control unit, and D is a duty / toner amount. A table, E is a temperature sensor, F is a temperature correction unit, and G is a toner remaining amount display unit. As is well known, the timer B emits a clock signal at a predetermined time interval, and the photodetector A
From this, an ON / OFF signal is input to the timer control unit C ₁ at predetermined intervals. The duty control unit C ₂ calculates the toner remaining amount based on the signal from the photodetector A processed by the timer control unit C ₁ and the information from the duty / toner amount table, and the toner remaining amount display unit G displays the toner remaining amount. Is displayed. Further, in this embodiment, the temperature inside the toner storage chamber 59 is detected by the temperature sensor E, and the correction is performed by the hardness change of the elastic member 54b due to the temperature as described later.

Next, the operation of the above embodiment will be described with reference to FIGS. In FIG. 15, (A) to (C) show the case where the remaining amount of the toner T is small, and (D) shows the case where the toner amount is large. Further, (A) shows a state in which the agitator 54 and the elastic member 54b have just passed through the transmissive photosensors 90, 91, (B) shows a state in which they have passed for a while, and (C) shows a state in which they have rotated considerably after passing. Indicates.

As described above, the elastic member 54b made of silicon rubber or the like is fixed to the agitator 54, which is a stirring member, and integrally rotates about the rotating shaft 54a. The elastic member 54b rotates with the rotation of the agitator 54,
The tip portion of the toner T is periodically moved while contacting and moving with respect to the bottom surface and the side surface of the lower portion of the toner storage chamber 59 (this side surface corresponds to the wall portion of the sensor housing portion 59b shown in FIG. 9), and the toner T is periodically moved. A light transmission type photo sensor 9 while stirring
The toner adhering to the transparent wall surface corresponding to the optical path of 0.91 is cleaned.

As shown in FIG. 15A, immediately after the agitator 54 and the elastic member 54b have passed through the transmitted light of the light transmissive photosensors 90 and 91 in the state where the remaining amount of toner is small, the toner T is removed from the agitator 54. The light is scraped up by the elastic member 54, the transmitted light of the transmissive photosensors 90 and 91 is released, and the output of the sensor is changed from the OFF state to the ON state.

The elastic member 54b is the light transmission type photo sensor 9
After a while after passing through 0 and 91, the toner T scraped up by the agitator 54 and the elastic member 54 begins to fall down and accumulates at the bottom of the toner storage chamber 59, as shown in FIG. 15B. Eventually, the toner T is shielded from the transmitted light of the light transmissive photosensors 90 and 91, and the output of the sensor changes from ON to OFF.

Further, as shown in FIG. 15C, when the agitator 54 and the elastic member 54 come to the upper side, the agitator 5
4 and the toner T scraped by the elastic member 54
Are almost dropped, and are collected at the bottom of the toner storage chamber 59 to block the transmitted light of the light transmissive photosensors 90 and 91. In this way, when the remaining toner amount is relatively small, the agitator 5
4 and the elastic member 54 rotate, and the toner T is agitated periodically.
The output of N and OFF is repeated.

In this case, the timing at which the sensor output changes from ON to OFF, that is, the agitator 54
The angle between the elastic member 54 and the elastic member 54 differs depending on the amount of remaining toner. When the amount of toner is relatively large, the agitator 54 and the elastic member 54 must scrape up a relatively large amount of toner, and therefore, in the state of FIG. Output O
The timing of becoming FF becomes earlier. On the contrary, when the toner amount is relatively small, the agitator 54 and the elastic member 54 need only scrape a small amount of toner, and therefore, FIG.
In the state (B), the speed at which a smaller amount of toner drops is also slow, and the timing at which the sensor output is turned off is delayed.

FIG. 15D shows the case where the toner amount is large, and immediately after the agitator 54 and the elastic member 54b have passed through the transmitted light of the light transmission type photosensors 90, 91, a large amount of toner is used to transmit the transmission type photosensor 90, 91. The transmitted light of 91 is shielded, and the output of the sensor is turned ON only during a period of little or very little. FIG. 16 shows changes in the outputs of the light transmission type photosensors 90 and 91. In addition, as in the above-described embodiment, the light-transmitting photosensor may be a pair, or two or more pairs may be used. If two or more pairs are provided, the output of each sensor can be summed. In the figure, t is the stirring cycle, t ₁ is the ON output of the light transmission type photosensor, and t ₂ is the rising time.

FIG. 17 shows the relationship between the remaining amount of toner in the toner storage chamber and the ratio of t ₁ to t (hereinafter referred to as a duty ratio) binarized at 50% of the output. As shown in the figure, the duty ratio (%) of t ₁ / t increases as the remaining toner amount decreases. In this example, when the duty ratio exceeds about 35%, the remaining amount of toner is about 75 g, and it can be used as a standard that the remaining amount of toner is low (nitoner empty display).

When a material such as silicon rubber is used as the elastic member 54b, the hardness thereof changes with the temperature change, so the temperature of the toner T or the direct elastic member 54b.
A sensor E (FIG. 14) that detects the temperature of b is provided. Since the hardness of the elastic member 54b decreases as the temperature rises, the toner drops more quickly after being scraped up by the agitator 54 and the elastic member 54b, and the light-shielding time of the light transmissive photosensor is reduced. It tends to be long. Therefore, the output of the sensor can be corrected by such a temperature change.

A mesh gauge or a repose angle measuring device (not shown) is generally used as a means for measuring the fluidity of the toner T itself, but the present invention provides a determination method similar to this usage condition. Using the configuration shown, the required amount of toner is filled in the toner storage chamber, and the fluidity or repose angle of the toner is detected by detecting the duty ratio,
It is also possible to determine whether or not the toner itself is suitable, and it is also possible to correct the output of the light transmissive photosensor based on the detected angle of repose. That is, when the angle of repose of the toner becomes large, the toner is slow to drop after being scraped up by the agitator 54 and the elastic member 54b, and the light blocking time of the light transmissive photosensor tends to be shortened.
Therefore, the output of the sensor can be corrected by the detected angle of repose.

Although the embodiments have been described in detail with reference to the accompanying drawings of the present invention, the present invention is not limited to the above embodiments, and various embodiments within the spirit and scope of the present invention, It should be noted that variations, modifications, etc. are possible.

[0058]

As described above, according to the present invention, since the means for cleaning the transparent wall of the storage chamber from the inside of the storage chamber is provided, the toner does not adhere to the transparent wall of the storage chamber. Therefore, good transparency is always maintained, and the remaining toner amount can be accurately detected. Moreover, since the elastic member as the cleaning means is attached to the agitator as the stirring means, the elastic member is also rotated by the rotation of the agitator to clean the transparent wall. Therefore, it is not necessary to provide a special drive source for the cleaning unit, and the remaining toner amount can be detected efficiently at low cost, efficiently and accurately.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a conventional technique.

FIG. 2 is an external view of an image forming apparatus to which the present invention can be applied.

FIG. 3 is a sectional view of an image forming apparatus to which the present invention can be applied.

FIG. 4 is a configuration diagram of a process cartridge to which the present invention can be applied.

FIG. 5 is an explanatory diagram of an image forming apparatus to which the present invention can be applied.

FIG. 6 is a diagram illustrating an operation of the image forming apparatus to which the present invention can be applied.

FIG. 7 is a front view showing an embodiment of the present invention.

8 is a cross-sectional view taken along line 8-8 of FIG.

9 is a cross-sectional view taken along line 9-9 of FIG.

FIG. 10 is a cross-sectional view of a toner storage unit.

FIG. 11 is a cross-sectional view of a remaining amount detection unit.

FIG. 12 is a circuit diagram of an embodiment of the present invention.

FIG. 13 is a circuit diagram of another embodiment of the present invention.

FIG. 14 is a block diagram showing an embodiment of the present invention.

FIG. 15 is a diagram showing an operation of toner remaining amount detection in the embodiment of the present invention.

FIG. 16 is a diagram showing an output of a sensor.

FIG. 17 is a diagram showing the relationship between the output of the sensor and the remaining amount of toner.

[Explanation of symbols]

 2 ... Process cartridge 4 ... Drum cartridge 5 ... Developing device 7 ... Optical unit 9 ... Toner remaining amount detecting unit 40 ... Photosensitive drum 50 ... Developing roller 54 ... Agitator (stirring means) 54a ... Rotating shaft 54b ... Elastic member 58 ... Developing chamber 59 ... Storage room 90, 91 ... Transmissive photosensor 92 ... Case 96 ... Judgment circuit

Claims (4)

[Claims] 1. A storage chamber (59) for storing toner, an agitating means (54) for agitating the toner in the storage chamber, and the agitated toner is supplied from the storage chamber to a developing chamber, and the developing chamber. Means for conveying the toner to the image carrier (40) at
Detecting means (90, 91) for optically detecting the presence / absence of toner in the storage chamber by means of at least a pair of light emitting element and light receiving element through the lower transparent wall in the storage chamber (59); Means for cleaning the wall from inside the storage room (5
4b) is included, and the toner remaining amount detecting device of the developing device is characterized by comprising. 2. The stirring means (54) comprises a rotating shaft (54).
The cleaning means (54b) comprises an elastic member attached to the agitator, which rotates around a), and the elastic member is configured to move while contacting the transparent wall by the rotation of the agitator. 2. The apparatus according to claim 1, further comprising means for measuring a ratio of continuous time of transmitted light during one rotation of the stirring means, and continuously obtaining toner remaining amount data during stirring. 3. The elastic member (54b) is made of a material whose hardness changes with temperature, such as silicone rubber, and is provided with a temperature detecting means (E) for detecting the temperature of the elastic member, and the elastic member (54b) is elastic by temperature change. The device according to claim 2, wherein a change in hardness of the member (54b) corrects a change in continuous time of transmitted light between the light emitting element and the light receiving element. 4. As a means for detecting the fluidity of the toner in the storage chamber (59), a predetermined amount of toner is filled in the storage chamber,
A means for measuring the ratio of the continuous time of the transmitted light is provided, data of the fluidity of the toner is obtained, and it is determined whether or not the toner is a suitable developer based on the fluidity of the detected toner. The device according to claim 1, characterized in that