JP2001228697A - Developer residual amount detecting device, developing device, process cartridge and electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect developer residual amount regardless of an image forming mode with respect to an electrophotographic image forming device having plural image forming modes and switching the frequency of developing bias voltage at the time of writing an image in accordance with the image forming mode. SOLUTION: An antenna 54 is arranged in parallel with the developing sleeve 52 of a developing device 5, and a detection circuit 56 is connected to the antenna 54. At the time of detecting developer residual amount, specified developing bias voltage is applied to the sleeve 52 from a developing bias power source 55 and toner residual amount between the sleeve 52 and the antenna 54 is detected as the change of electrostatic capacity by the circuit 56. In such a case, the developing bias voltage having single frequency is applied to the sleeve 52 regardless of the image forming mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electrophotographic system in which an electrostatic latent image is formed on an image carrier by an electrophotographic method, and the electrostatic latent image is visualized by a developer contained in a developing device. The present invention relates to a photographic image forming apparatus, a developing device, a process cartridge, and a developer remaining amount detecting device capable of sequentially detecting the remaining amount of developer contained in a developer container.

Here, as an electrophotographic image forming apparatus, for example, an electrophotographic copying machine, an electrophotographic printer (for example, L
ED printers, laser beam printers, etc.), and electrophotographic facsimile machines.

A process cartridge is a cartridge in which at least one of a charging unit, a developing unit, and a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is detachably mountable to an electrophotographic image forming apparatus main body. Or a cartridge in which at least the developing means and the electrophotographic photosensitive member are integrally formed, and this cartridge is detachable from the main body of the electrophotographic image forming apparatus.

[0004]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus such as a laser printer, if a developer (toner) runs short during operation, there is an image defect such as a decrease in image density or image loss.
Usually, there is provided a means for detecting the remaining amount of toner in the developing device, and displaying and warning when toner is exhausted, so that toner is supplied before an image defect occurs. . As a means for detecting the remaining amount of toner, for example, a capacity detection type is known.

FIG. 11 shows an example of a conventional developing device for detecting a remaining amount by a capacity detection method. In FIG. 11, a developing device 105 includes a developing blade 153 which is a developer regulating member,
And a developing sleeve 152 as a developer carrier. In the vicinity of the developing sleeve 152, an antenna 154, which is a conductive detecting member, is disposed in parallel with the developing sleeve 152. A change in the amount of toner between the developing sleeve 152 and the antenna 154 is regarded as a change in the electrostatic capacity, and the remaining amount of the toner Perform detection.

The detection of the capacitance is performed, for example, when a developing bias composed of an oscillating voltage obtained by superimposing an AC voltage and a DC voltage is applied to the developing sleeve 152 from a developing bias power supply 155, and the antenna is connected between the antenna 154 and the ground. The flowing current can be converted into a DC voltage in the detection circuit 156 and read.

On the other hand, in recent years, in order to meet diversifying demands for printing, an image forming apparatus capable of switching resolution / speed depending on the purpose of printing, and a type of a recording material as a recording medium (for example, cardboard or OHT) are used. 2. Description of the Related Art There is an image forming apparatus that switches the speed in order to secure the fixing property.

In such an image forming apparatus, the frequency of the developing bias (oscillating voltage) is switched according to the image forming mode (resolution / process speed),
It is possible to make the developability of each image forming mode equal.

[0009]

However, when the frequency of the developing bias is switched in accordance with the image forming mode in the image forming apparatus provided with the toner remaining amount detecting means as described above, it is detected by the frequency of the developing bias. However, there is a problem that the voltage values are different. For example, the frequency of the developing bias is 2.0 kHz and 2.4 kHz.
FIG. 1 shows the relationship between the remaining amount of toner and the detected voltage when z is
As shown in FIG. In this configuration, when the remaining amount of toner becomes 50 g or less, an image defect occurs due to insufficient toner. Therefore, if the voltage for judging the absence of toner is set to 3 V, an appropriate judgment can be made when the frequency of the developing bias is 2.0 kHz. Will be done. Conversely, when the determination voltage for no toner is set to 5 V, when the frequency of the developing bias is 2.0 kHz,
It is determined that there is no toner when a large amount of toner remains.

Therefore, an object of the present invention is to provide an electrophotographic image forming apparatus which has a plurality of image forming modes and switches the frequency of an oscillating voltage at the time of writing an image in accordance with the image forming mode. It is an object of the present invention to provide a developer remaining amount detecting device, a developing device, a process cartridge, and an electrophotographic image forming apparatus capable of detecting a developer remaining amount.

[0011]

The above object is achieved by a developer remaining amount detecting device, a developing device, a process cartridge, and an electrophotographic image forming apparatus according to the present invention. In summary, the present invention provides a developer carrier mounted on an electrophotographic image forming apparatus main body and for transporting a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member. And an electrophotographic image forming apparatus having a plurality of image forming modes, and switching a frequency of an oscillating voltage applied to the developer carrier according to the image forming modes. An electrode disposed on the developer carrier with a developer interposed therebetween, and a developing device present in the developing device by a voltage induced on the electrode when an oscillating voltage is applied to the developer carrier. In the developer remaining amount detecting device for detecting the remaining amount of the developer, a vibration voltage of a single frequency is applied to the developer carrying member regardless of the image forming mode when the remaining amount of the developer is detected. With developer remaining amount detection device That.

According to a second aspect of the present invention, a developer carrier for transporting a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and the developer An electrode disposed on the carrier via a developer, and detecting a remaining amount of the developer present in the developing device by a voltage induced on the electrode when an oscillating voltage is applied to the developer carrier. An electrophotographic image having a plurality of image forming modes and switching a frequency of a vibration voltage applied to the developer carrier according to the image forming mode. In the developing device mounted on the forming device, the developer remaining amount detecting unit applies a vibration voltage of a single frequency to the developer carrying member regardless of the image forming mode when the developer remaining amount is detected. Developing characterized by Location is provided.

According to a third aspect of the present invention, there is provided a process cartridge detachable from an electrophotographic image forming apparatus having a plurality of image forming modes, wherein (a) an electrophotographic photosensitive member; and (b) the electrophotographic photosensitive member. A developing device having a developer carrier for transporting a developer to the electrophotographic photoreceptor for developing an electrostatic latent image formed on the body; and (c) a developer interposed between the developer carrier and the developer carrier. Having electrodes arranged in
A developer residual amount detecting unit that detects a residual amount of the developer present in the developing device by a voltage induced at the electrode when an oscillating voltage is applied to the developer carrier, and The frequency of the oscillating voltage applied to the developer carrier is switched according to the image forming mode, and when the remaining amount of the developer is detected, the remaining amount of the developer is detected by a single frequency regardless of the image forming mode. A process cartridge is provided, wherein the vibration voltage is applied to the developer carrier.

According to a fourth aspect of the present invention, there is provided an electrophotographic image forming apparatus having a plurality of image forming modes for forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; (E) an electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member; and (c) a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member, by the electrophotographic method. A developing device having a developer carrier for conveying to the photoreceptor; and (d) an electrode arranged with the developer interposed between the developer carrier and applying an oscillating voltage to the developer carrier. And a developer remaining amount detecting means for detecting a remaining amount of the developer present in the developing device by a voltage induced on the electrode when the image forming mode is performed. The frequency of the vibration voltage applied to the carrier is switched, and the developer remaining At the time of detection, the electrophotographic image forming apparatus is characterized in that the developer remaining amount detecting means applies a vibration voltage of a single frequency to the developer carrier irrespective of the image forming mode. .

According to a fifth aspect of the present invention, there is provided an electrophotographic image forming apparatus for detachably mounting a process cartridge, having a plurality of image forming modes, and forming an image on a recording medium. A) a developing device including an electrophotographic photosensitive member, a developer carrying member that transports a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and An electrode disposed on the body via a developer, and detecting a remaining amount of the developer present in the developing device by a voltage induced on the electrode when an oscillating voltage is applied to the developer carrier Mounting means for detachably mounting a process cartridge having developer remaining amount detecting means; (b) electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member;
When an image is formed, the frequency of an oscillating voltage applied to the developer carrier is switched according to the image forming mode. An electrophotographic image forming apparatus is provided in which an oscillating voltage of a single frequency is applied to the developer carrier irrespective of the mode.

In one embodiment of the present invention, the image forming mode further includes a process speed changing unit, wherein the image forming mode has a different process speed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developer remaining amount detecting device, a developing device, a process cartridge, and an electrophotographic image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS.

In the electrophotographic image forming apparatus of this embodiment shown in FIG. 2, a photosensitive drum 3, which is an electrophotographic photosensitive member, is rotated in the direction of arrow A, and a primary charger 4 comprising a charging roller.
Is charged uniformly. A scanner unit 1, which is an electrostatic latent image forming unit including a laser, a polygon mirror, and a lens system, scans and outputs a laser beam L modulated in accordance with an image signal. Irradiation is performed on the photosensitive drum 3 to form an electrostatic latent image on the surface thereof. The electrostatic latent image is stored in a developer container 50 of the developing device 5 by a developer (toner).
The image is developed as a toner image by 51 and visualized.

On the other hand, the recording material 7 as a recording medium stored in the cassette 71 is fed by a paper feed roller 72 in synchronism with the formation of a latent image on the photosensitive drum 3 and a registration roller 73.
Is supplied up to. Then, the recording material 7 is conveyed to a transfer charger 6 composed of a transfer roller in synchronization with the leading end of the latent image formed on the photosensitive drum 3 by the registration roller 73, and a toner image is recorded by the transfer charger 6. It is transferred to the material 7. After the toner image is transferred onto the recording material 7, the fixing device 8 permanently fixes the toner image on the recording material 7, and is finally discharged outside the apparatus. The toner remaining on the photosensitive drum 3 is removed by a cleaning device 9 using a cleaning blade made of an elastic blade.

The image forming apparatus of this embodiment has a plurality of print modes having different resolutions, that is, an image forming mode. The print mode is an operation panel 30 including a process speed changing unit or a host computer (not shown). Can be freely selected by the user.
When the print mode is switched, settings such as the process speed, various biases, and the amount of laser light can be switched as appropriate.

For example, when the resolution can be switched between 600 dpi (mode A) and 1200 dpi (mode B), the process speed is 100 mm / sec.
(Mode A) and 50 mm / sec, the developing bias has a frequency of 2.0 kHz (mode A) and 2.4 kHz (mode B), and the laser light amount is 0.35 μJ / cm.
² (mode A) and 0.2 μJ / cm ² (mode A).

Next, a developer remaining amount detecting device (developing agent remaining amount detecting means) according to the present embodiment will be described with reference to FIG.

The developer remaining amount detecting device includes a developing sleeve 5
2. Antenna 5 as developer remaining amount detecting member (electrode)
4, a detection circuit 56 provided between the antenna 54 and the ground, and a developing bias power supply 55. When detecting the remaining amount of the developer, a developing bias voltage composed of a vibration voltage obtained by superimposing a predetermined AC voltage and a DC voltage is applied to the developing sleeve 52 from the developing bias power supply 55,
The detection circuit 5 detects a current flowing between the antenna 54 and the ground.
At 6, it can be read by converting it to a DC voltage.

Next, the procedure for detecting the remaining amount of toner will be described with reference to the flowchart of FIG. In FIG. 3, the preparatory rotation means that the main switch for connecting the image forming apparatus to an external power supply is turned on, the fixing device 8 is heated and its warm-up is completed, or the toner 51 is supplied into the developing device 5. This is an operation for rotating the photosensitive drum 3 later and cleaning the photosensitive drum 3 and the transfer roller 6. The pre-rotation is an operation caused by a print start command. The primary charging device 4 is actuated simultaneously with the rotation of the photosensitive drum 3 to adjust the amount of laser light.
This is an operation for performing uniform charging, cleaning, and the like.
Further, post-rotation is an operation in which the rotation of the photosensitive drum 3 is continued for a predetermined time even after printing is completed, and the primary charger 4 is operated to eliminate the sensitivity history of the photosensitive drum 3 and the like.

First, when the power of the main body is turned on (S1), the warm-up of the fixing device 8 is completed, and when the image forming apparatus is ready for printing, the preparatory rotation is performed (S2). During the preparatory rotation, the developing bias (mode A) is applied (ON) and the remaining amount of toner is detected (S
3). When the toner-out condition is detected (S4), a toner-out warning display is performed (S5), and the process enters a standby mode for waiting for a print start command (S6). Then, when toner is supplied during standby (S7), the preparatory rotation and toner remaining amount detection are performed again, and the process returns to standby (S2 to S6).

When a print start command is input during standby (S8), the settings of the process speed, various biases, the amount of laser light, and the like are appropriately switched according to the selected print mode, and subsequent to the pre-rotation (S9). Printing is performed (S10). During post-rotation after printing (S1
1) When mode B is selected, only the setting of the developing bias is switched to mode A, and the remaining amount of toner is detected in the same manner as described above (S12). When the toner-out state is detected (S13), a toner-out warning display is performed (S14), and otherwise, the apparatus enters a standby mode for waiting for a print start command (S6).

Next, the operation sequence when detecting the remaining amount of toner will be described in detail with reference to FIG. In FIG. 4, the horizontal axis represents the flow of time. Since the developing portion and the transfer portion are respectively located on the downstream side in the rotation direction of the photosensitive drum 3 with respect to the charging portion, the application time of the development bias voltage, the application time of the transfer bias voltage, and the transfer roller cleaning bias voltage At the time of application, the photosensitive drum 3
Are shifted to the delay side (rightward) by the time required to move the above distances. In this embodiment,
The operation related to the detection of the remaining amount of toner is performed in the hatched portion in FIG. 4 during the preparation rotation and the post-rotation.

First, the power is turned on and the photosensitive drum 3 is turned on.
, And primary charging is performed simultaneously. When the primary charged portion on the photosensitive drum surface reaches the developing portion,
A developing bias voltage (mode A) is applied to the developing sleeve 52, and the remaining amount of toner is detected by a voltage induced in the antenna 54 during that time. Even if the developing bias voltage is turned on at the time of detection, the surface of the photosensitive drum 3 is uniformly charged by the primary charger 4, so that the toner does not adhere to the photosensitive drum 3. However, there is a possibility that the component (inverted toner) of which the polarity of the toner is inverted may adhere. Has been prevented. Thereafter, a transfer roller cleaning bias voltage of the same polarity (-) as that of the toner of the normal charge polarity is applied to the transfer roller 6, and the toner of the normal charge polarity adhering to the surface of the transfer roller 6 is removed from the surface. Then, the rotation of the photosensitive drum 3 stops, and a series of operations ends.

As described above, in this embodiment, in the image forming apparatus which has a plurality of print modes and switches the frequency of the developing bias at the time of writing the image in accordance with the print mode, the image is applied to the developing sleeve when the remaining amount of toner is detected. By setting the frequency of the developing bias to be a single frequency, it was possible to accurately detect the amount of remaining toner regardless of the print mode.

In the present embodiment, the toner remaining amount is detected during the preparatory rotation and the post-rotation. However, the present invention is not limited to this. Etc.

Further, the image forming apparatus is not limited to the laser printer adopting the reversal developing method described in the present embodiment, and the present invention is applied to an electrophotographic image forming apparatus such as a copying machine of a regular developing method. Of course, it is included in the object.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIG.

The present embodiment is characterized in that the toner remaining amount detecting device according to the present invention is applied to a process cartridge in which a photosensitive drum, a charging roller, a developing device, and a cleaning device are collectively unitized. is there. When it is determined by the remaining toner amount detection that there is no toner, the user only needs to replace the process cartridge, and there is no dirt due to toner supply work, and maintenance-free operation can be realized.

Hereinafter, the process cartridge 10 of this embodiment will be described with reference to FIG.

In the process cartridge 10, the photosensitive drum 3, the charging roller 4, the developing device 5, and the cleaning device 9 are collectively unitized, and these components are located at predetermined positions within the process cartridge 10. Process cartridge 1
Numeral 0 is inserted and mounted in a predetermined manner with respect to the mounting means 20 (see FIG. 1) of the image forming apparatus main body, and conversely, can be inserted and removed from the image forming apparatus main body.

The developing device 5 is provided with a developing sleeve 52 and an antenna, which are components of the toner remaining amount detecting device according to the present invention. The developing sleeve 52 is provided with a developing bias power supply 55 and an antenna 54 and a ground. Between the detection circuit 5
6 are connected.

It is obvious that the same effects as those of the first embodiment are applied to the procedure and operation sequence for detecting the remaining amount of toner.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG.

The feature of this embodiment resides in that a plate-shaped conductive plate is used as a developer remaining amount detecting member. Since the detection member is a plate having a large area, it is possible to detect the remaining amount of toner in a wide range. Therefore, it is possible to sequentially detect the remaining amount of toner over almost the entire use period of the process cartridge.

Hereinafter, the developer remaining amount detecting device according to the present embodiment will be described with reference to FIG. The developer remaining amount detecting device includes a developing sleeve 52, a plate 54A as a developer remaining amount detecting member (electrode), a detecting circuit 56 provided between the plate 54A and the ground, and a developing bias power supply 55.
It is composed of At the time of detection, the developing sleeve 5
2, a predetermined developing bias voltage is applied from a developing bias power supply 55. The plate 54A is the process cartridge 1
0A and the main body of the image forming apparatus can be provided. However, in this embodiment, the configuration is such that the main body of the image forming apparatus is provided in order to reduce the cost of the process cartridge.

The same procedure as that of the first embodiment can be applied to the procedure and operation sequence for detecting the remaining amount of toner, and it is obvious that the same effect can be obtained.

The relationship between the remaining amount of toner and the detected voltage actually obtained by the above configuration is as shown in the graph of FIG.

As a comparative example, a case using the antenna described in the second embodiment is also described.

In the case of the antenna of the comparative example, the remaining amount of toner is 1
In the plate of this embodiment, the change is almost linear from the full state to the absence of the toner, and the remaining amount of the toner remains almost over the entire use period of the process cartridge. It became possible to detect the amount.

According to the present invention described with reference to each of the first to third embodiments, the amount of the remaining developer can be sequentially detected with high accuracy.

The developer remaining amount information from the developer remaining amount detecting device is displayed by the developer amount displaying means. For example, the detection information obtained by the above-described developer remaining amount detection device is displayed on a terminal screen of a user's personal computer or the like as shown in FIGS. 8 and 9. 8 and 9, the user is notified of the amount of the developer based on which part of the gauge 52 the needle 51 that moves according to the amount of the developer is pointing. FIG.
0, L is directly applied to the electrophotographic image forming apparatus main body.
A display unit such as ED is provided, and LEDs are displayed according to the amount of developer.
53 and the like may be blinked.

In the above-described embodiment, when the remaining amount of the developer stored in the container is initially set to 100%, the remaining amount of the developer is reduced to the entire area of about 30% to 0%. Over time. However, the present invention is not limited to this. For example, the remaining amount of the developer in the container may be 50% to 0%, or 40%.
Detection may be performed sequentially over an area of up to 0%. Here, the remaining amount of the developer of 0% does not only mean that the developer has completely disappeared. For example, the remaining amount of the developer of 0% includes that the remaining amount of the developer is reduced to such an extent that a predetermined image quality (development quality) cannot be obtained even if the developer remains in the container. It is.

[0049]

As is apparent from the above description, according to the developer remaining amount detecting device, the developing device, the process cartridge and the electrophotographic image forming apparatus of the present invention, the image forming mode is set when the remaining amount of the developer is detected. An electrophotographic image having a plurality of image forming modes by applying an oscillating voltage of a single frequency to the developer carrier regardless of the image forming mode, and switching the frequency of the oscillating voltage at the time of image writing according to the image forming mode Also in the forming apparatus, it is possible to accurately detect the remaining amount of the developer regardless of the image forming mode.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a developer remaining amount detection device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an image forming apparatus according to one embodiment of the present invention.

FIG. 3 is a flowchart showing an embodiment of the developer remaining amount detection of the present invention.

FIG. 4 is a sequence chart showing an embodiment of the developer remaining amount detection of the present invention.

FIG. 5 is a configuration diagram illustrating a process cartridge according to an embodiment of the present invention.

FIG. 6 is a configuration diagram illustrating a developer remaining amount detection device according to another embodiment of the present invention.

FIG. 7 is a graph for explaining an effect of the developer remaining amount detecting device of FIG. 6;

FIG. 8 is a diagram illustrating an embodiment of a developer remaining amount display.

FIG. 9 is a view showing another embodiment of the developer remaining amount display.

FIG. 10 is a diagram showing another embodiment of the developer remaining amount display.

FIG. 11 is a configuration diagram illustrating an example of a conventional developer remaining amount detection device.

FIG. 12 is a graph for explaining a detection result of the developer remaining amount detection device of FIG. 8;

[Explanation of symbols]

 Reference Signs List 3 photosensitive drum (electrophotographic photosensitive member) 5 developing device 10 process cartridge 20 mounting means 52 developing sleeve (developer carrier) 54 antenna (electrode) 54A plate (electrode) 55 developing bias power supply 56 detection circuit

Claims (6)

[Claims] 1. An electrophotographic image forming apparatus main body,
A developing device having a developer carrier for transporting a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and having a plurality of image forming modes. An electrode provided in an electrophotographic image forming apparatus that switches a frequency of an oscillating voltage applied to the developer carrier according to the image forming mode, the electrode being arranged via the developer with respect to the developer carrier. A developer remaining amount detecting device for detecting a remaining amount of the developer present in the developing device by a voltage induced at the electrode when an oscillating voltage is applied to the developer carrying member; A developer remaining amount detecting device, wherein at the time of detection, a vibration voltage of a single frequency is applied to the developer carrier irrespective of the image forming mode. 2. A developer carrier for transporting a developer to the electrophotographic photoconductor for developing an electrostatic latent image formed on the electrophotographic photoconductor, and a developer interposed between the developer carrier and the developer carrier. And a developer remaining amount detecting means for detecting a remaining amount of the developer present in the developing device by a voltage induced at the electrode when an oscillating voltage is applied to the developer carrying member. A developing device having a plurality of image forming modes, wherein the frequency of an oscillating voltage applied to the developer carrier is switched according to the image forming mode. The developing device, wherein the developer remaining amount detecting means applies a vibration voltage of a single frequency to the developer carrier irrespective of the image forming mode when the developer remaining amount is detected. 3. A process cartridge detachable from an electrophotographic image forming apparatus having a plurality of image forming modes, wherein: (a) an electrophotographic photosensitive member; and (b) an electrostatic latent image formed on the electrophotographic photosensitive member. A developing device having a developer carrier for transporting a developer to the electrophotographic photoreceptor to develop the electrophotographic photosensitive member, and (c) an electrode arranged via the developer with respect to the developer carrier, A developer residual amount detecting unit that detects a residual amount of the developer present in the developing device by a voltage induced at the electrode when an oscillating voltage is applied to the developer carrier, and The frequency of the oscillating voltage applied to the developer carrier is switched according to the image forming mode, and when the remaining amount of the developer is detected, the remaining amount of the developer is detected by a single frequency regardless of the image forming mode. The oscillation voltage of the developing A process cartridge, wherein the voltage is applied to an agent carrier. 4. An electrophotographic image forming apparatus having a plurality of image forming modes for forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; Electrostatic latent image forming means for forming a latent image,
(C) a developing device including a developer carrier for transporting a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member; and (d) the developer carrier. Having an electrode disposed with a developer interposed therebetween, and detecting the remaining amount of the developer present in the developing device by a voltage induced on the electrode when an oscillating voltage is applied to the developer carrier. Agent detection means, and at the time of image formation,
The frequency of the oscillation voltage applied to the developer carrier is switched according to the image forming mode, and when the remaining amount of the developer is detected, the remaining amount of the developer is detected by a single unit regardless of the image forming mode. An electrophotographic image forming apparatus, wherein an oscillating voltage having a frequency is applied to the developer carrier. 5. An electrophotographic image forming apparatus for detachably mounting a process cartridge, having a plurality of image forming modes, and forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; A developing device having a developer carrier for transporting a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the photographic photosensitive member, and A developer remaining amount detecting unit having an electrode disposed therein, and detecting a remaining amount of the developer present in the developing device by a voltage induced on the electrode when an oscillating voltage is applied to the developer carrier; Mounting means for removably mounting a process cartridge having
(B) electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photoreceptor, wherein an image is applied to the developer carrier according to the image forming mode during image formation. The frequency of the oscillating voltage is switched, and when the remaining amount of the developer is detected, the developer remaining amount detecting unit applies a single frequency of the oscillating voltage to the developer carrier irrespective of the image forming mode. Electrophotographic image forming apparatus. 6. The electrophotographic image forming apparatus according to claim 4, further comprising a process speed changing unit, wherein the image forming mode has a different process speed.