JP2001166582A - Developing device, process cartridge, and electrophotographic image forming device - Google Patents

Abstract

(57) [Problem] To accurately detect the amount of remaining toner without affecting the image density. A developing bias is output at a predetermined timing from the start of a recording operation. At this time, the duty of the AC bias is set to 50%, which is a predetermined value when detecting the remaining amount of toner, regardless of the image density setting. Due to the output of the developing bias, the toner remaining amount detection value changes according to the toner remaining amount in the toner container, and becomes saturated at a timing. Further, at a timing, the duty of the AC bias is set to a value (duty 70%) according to the image density setting. After that, the leading edge of the first recording paper reaches the cartridge section,
The development processing is performed at a predetermined image density. The process of detecting the remaining amount of toner at the start of the recording operation is performed between timings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a method of forming an electrostatic latent image on an electrophotographic photosensitive member by an electrophotographic method and visualizing the electrostatic latent image with a developer contained in a developing device. The present invention relates to an electrophotographic image forming apparatus, and more particularly, to an electrophotographic image forming apparatus having a developer remaining amount detecting device for detecting a remaining amount of a developer contained in a developer container, and further relates to a process cartridge and a developing device.

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.), electrophotographic facsimile machines, and electrophotographic word processors.

[0003] A process cartridge is a cartridge in which at least one of a charging means, a developing means and a cleaning means 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 at least the developing means and the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is made 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 which performs development using toner (developer), a remaining toner detecting device is provided in the apparatus to detect the remaining toner in a toner container. Then, the user is notified of the information by display means or the like.

FIG. 13 shows a configuration example of a conventional toner remaining amount detecting device.

In FIG. 13, a process cartridge (hereinafter, referred to as a “cartridge”) 101 includes an electrophotographic photosensitive member 102, a charging unit 103, and a developing sleeve 104 which accommodates a developer (toner) and is a developer carrier. The developing device 120 having the developer container (toner container) and the cleaning unit 116 are integrally formed as a cartridge, and are detachably attached to an image forming apparatus main body (not shown).

[0007] To the developing sleeve 104, a developing bias in which an AC voltage is superimposed on a DC voltage generated by a high-voltage power supply 106 as a developing bias applying means is applied.

In the toner container 112, an antenna electrode 105 for detecting the remaining amount of toner is arranged. The detection of the remaining amount of toner is performed by detecting the capacitance between the antenna electrode 105 and the developing sleeve 104. Since the dielectric constant of the material forming the toner is different from the dielectric constant of the atmosphere, the capacitance changes according to the amount of toner distributed between the antenna electrode 105 and the developing sleeve 104. That is, the toner amount can be determined from the detected capacitance value.

Here, a method of detecting the capacitance will be described.

The antenna electrode 105 is made of a conductive material and is connected to the capacitance detecting circuit 111. When a developing bias is applied to the developing sleeve 104 from the high-voltage power supply 106, the developing sleeve 104 and the antenna electrode 10
A current corresponding to the capacitance formed between the electrodes 5 is generated in the antenna electrode 105. The generated current Is is converted to a voltage Vs by the current / voltage conversion circuit 109. On the other hand, the current Iref is input to the capacitance detection circuit 111 via the reference capacitor 107, and is converted into the voltage Vref by the current / voltage conversion circuit. Further, the differential circuit 1
The calculation of Vs-Vref is performed by 10 and a signal Vt corresponding to the capacitance between the developing sleeve 104 and the antenna electrode 105 is output.

[0011]

However, as described above, by applying a developing bias, the developing sleeve 1
In the method of detecting the capacitance between the antenna 04 and the antenna electrode 105, there is a problem that the detection value Vt of the capacitance fluctuates when the driving duty of the developing bias changes. This problem occurs particularly in an image forming apparatus that controls the density of a recorded image by changing the amount of toner supplied from the developing sleeve to the electrophotographic photosensitive member by changing the driving duty of the developing bias.

The causes of the above problems are as follows. 1) By changing the duty of the developing AC bias, the frequency component of the developing bias changes, and the capacitance between the developing sleeve and the antenna electrode changes. 2) By changing the duty of the developing AC bias, the frequency component of the developing bias changes, and the capacitance of the reference capacitor changes.

Accordingly, an object of the present invention is to provide a developing device, a process cartridge, and an electrophotographic image forming apparatus which can accurately detect the remaining amount of a developer without affecting the image density.

[0014]

The above object is achieved by a developing device, a process cartridge and an electrophotographic image forming apparatus according to the present invention. In summary, the present invention is directed to an electrophotographic image forming apparatus main body, which stores a developer for developing an electrostatic latent image formed on an electrophotographic photosensitive member, and includes the developer in the electrophotographic photosensitive member. A developer container having a developer carrier for transporting the developer to the developer container, and a developer remaining amount detecting unit for detecting a developer amount in the developer container, wherein the developing device includes: In this method, a DC bias and an AC bias having an arbitrary duty are superimposed and applied to the developer carrier from a developing bias applying unit to perform a developing process. The developer remaining amount detecting unit is provided around the developer container. It is a method of detecting the amount of developer in the developer container by measuring the capacitance between the developer carrier and the electrode, and detecting the amount of developer.
A developing device, wherein the duty of an AC bias applied to the developer carrier is set to a predetermined value.

According to a second aspect of the present invention, there is provided a process cartridge detachably mountable to an electrophotographic image forming apparatus main body, wherein (a) an electrophotographic photosensitive member and (b) a photosensitive member formed on the electrophotographic photosensitive member. A developing device that contains a developer for developing an electrostatic latent image and has a developer container provided with a developer carrier for transporting the developer to the electrophotographic photosensitive member; and (c) the developer. And (d) the developing device applies a DC bias and an AC of an arbitrary duty to the developer carrier from a developing bias applying unit. A method of performing a developing process by superimposing bias application, wherein the developer remaining amount detecting means includes an electrode provided around the developer container,
The amount of the developer in the developer container is detected by measuring a capacitance between the developer carrier and the electrode, and the amount of the developer is applied to the developer carrier. A process cartridge is provided wherein the duty of the AC bias is set to a predetermined value.

According to a third aspect of the present invention, in an electrophotographic image forming apparatus for forming an image on a recording medium,
(A) an electrophotographic photosensitive member, (b) an electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, and (c)
A developer container that contains a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member and has a developer carrier for transporting the developer to the electrophotographic photosensitive member; (E) a developing device, and (d) a developer remaining amount detecting means for detecting an amount of the developer in the developer container.
The developing device is configured to perform a developing process by superimposing and applying a DC bias and an AC bias having an arbitrary duty to the developer carrier from a developing bias applying unit. An electrode provided around a container is provided, and a capacitance between the developer carrier and the electrode is measured to detect a developer amount in the developer container. The present invention provides an electrophotographic image forming apparatus, wherein a duty of an AC bias applied to the developer carrier is set to a predetermined value.

According to a fourth aspect of the present invention, there is provided an electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium.
An electrophotographic photoreceptor, and a developer carrier for housing a developer for developing an electrostatic latent image formed on the electrophotographic photoreceptor, and transporting the developer to the electrophotographic photoreceptor. Mounting means for detachably mounting a process cartridge having a developing device having a developer container, and (b) developer remaining amount detecting means for detecting an amount of developer in the developer container. (C) the developing device performs a developing process by superimposingly applying a DC bias and an AC bias having an arbitrary duty to the developer carrying member from a developing bias applying unit; The amount detecting means includes an electrode provided around the developer container,
The amount of the developer in the developer container is detected by measuring a capacitance between the developer carrier and the electrode, and the amount of the developer is applied to the developer carrier. An electrophotographic image forming apparatus is provided in which the duty of the AC bias is set to a predetermined value.

In one embodiment of the present invention, the density of a developer image formed on the electrophotographic photosensitive member is controlled by adjusting the duty of an AC bias applied to the developer carrier. You. The detection of the developer amount is as follows:
This is performed at a timing between the start of the recording operation and the start of the development processing. According to another aspect, the detection of the developer amount is performed at a timing between the end of the developing process and the end of the recording operation. Further, according to another aspect, the detection of the developer amount is performed at a timing when the development processing is not performed between the recording medium and the next recording medium when the development processing is continuously performed on a plurality of recording media. .

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developing device, a process cartridge and an 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. FIG. 1 shows an electrophotographic image forming apparatus of the present embodiment.

In FIG. 1, only one recording sheet 12 as a recording medium set on the recording sheet tray 2 is sent out from the recording sheet tray 2 by driving the pickup roller 3, and is fed in the direction of arrow A by the sheet feeding roller 3. The sheet is conveyed toward the registration roller 6. Further, the recording paper 12 is conveyed to the process cartridge 8 at a predetermined timing by driving the registration roller 6.

As shown in FIG. 2, the process cartridge 8 contains a developer (toner) and has a developing device 40 having a toner container 36 as a developer container having a developing sleeve 33 as a developer carrier. The charging unit 34, the cleaning unit 37, and the photosensitive drum 32, which is an electrophotographic photosensitive member, are integrally formed, and are detachably mounted on the image forming apparatus main body 1 via the mounting unit 50.

The surface of the photosensitive drum 13 is first charged by the charging means 34 by a latent image forming means including at least the charging means 34 and the scanner unit 11, and then the scanner unit 11 performs image exposure based on an image signal. And a latent image is formed. In the image exposure, main scanning is performed via a polygon mirror 15 and a reflection mirror 16 that rotate a laser beam from a laser light source 14 in the scanner unit 11, and a latent image is formed by rotation (sub-scanning) of the photosensitive drum 17. You.

The latent image on the photosensitive drum 13 is
The toner image is developed as a toner image by 0, and the toner image is transferred by the transfer device 7 to the recording paper 12 conveyed from the registration roller 6.

Subsequently, the recording paper 12 is conveyed to the fixing roller 9, where it is heated and pressurized, and the unfixed toner image on the recording paper 12 is fixed on the recording paper 12. The recording paper 12 is further conveyed to the outside of the image forming apparatus main body 1 by the paper discharge roller 10, and a series of recording processes is completed. These series of processes are controlled by a controller (not shown).

Next, the developing device 40 and the toner remaining amount detecting device in this embodiment will be described in detail.

The toner is stored in a toner container 36 and supplies the toner to the developing sleeve 33. A developing bias is applied to the developing sleeve 33 from a high-voltage power supply 38 which is a developing bias applying unit, and toner is applied to the photosensitive drum 13.
The toner image is formed on the photosensitive drum 13 by selectively moving upward.

The developing bias is 1 to -300 V DC voltage.
The AC voltage of 500 Vpp is superimposed. As described above, the developing bias is generated by the high voltage power supply 38.

FIG. 3 shows the configuration of the developing bias generating circuit in the high voltage power supply. The DC bias generation circuit 422 generates a high voltage of -300 V by driving the transformer 425.

The AC bias generation circuit 426 generates a clock signal DEV output from an engine controller (not shown).
Transformer 407 driven by the duty of CLK
Generates an AC bias. The duty of the AC bias can be changed by the duty of the clock signal DEVCLK. By changing the duty, the amount of toner moving from the developing sleeve 33 onto the photosensitive drum 13 is changed, whereby image density control can be performed. In the image forming apparatus of this embodiment, the image density control is performed by changing the duty of the AC bias in the range of 50% to 80%.

In the waveform diagram of the developing bias shown in FIG. 4, (a) shows that the duty of the AC bias is 50%,
(B) shows a case where the duty of the AC bias is 70%.

Next, the toner remaining amount detecting device will be described.

In the present embodiment, the detection of the remaining amount of toner is performed by using the antenna electrode 3 provided in the developing sleeve 33 and the toner container 36.
By detecting the capacitance between the five, the amount of toner in the toner container 36 is sequentially detected.

The antenna electrode 35 shown in FIG. 2 is made of a conductive material. The toner filled in the toner container 36 is arranged between the developing sleeve 33 and the antenna electrode 35, and the electrostatic capacity between the developing sleeve 33 and the antenna electrode 35 depends on the amount of toner in the toner container 36. The capacity changes. Since the dielectric constant of the toner used in this embodiment is higher than the dielectric constant of the atmosphere, the larger the amount of toner, the larger the capacitance value between the developing sleeve 33 and the antenna electrode 35. The antenna electrode 35 is connected to a capacitance detection circuit 500 shown in FIG.
Then, the capacitance value between the antenna electrode 35 is detected.

In FIG. 5, the signal ANT from the antenna electrode 35 is input to the capacitance detection circuit 500 as an alternating current I51 corresponding to the capacitance between the developing sleeve 33 and the antenna electrode 35. The AC current I51 is a diode 5
It is rectified by a resistor 501 and a capacitor 502 via 08 and 509 and converted into a DC voltage.

On the other hand, the signal REF from the high voltage power supply 38 is input to the electrostatic capacity detection circuit 500 as a developing bias output of the high voltage power supply 38, and an alternating current I52 is generated according to the capacitance value of the capacitor 512. The AC current I52 is supplied to the resistor 505 and the capacitor 50 via the diodes 510 and 511.
The rectified power is converted into a DC voltage at step 4. Operational amplifier 503
Are connected to resistors 506 and 507 of the power supply voltage Vcc.
A voltage obtained by superimposing the voltage conversion value of the current I52 on the divided voltage value Vk obtained by the above is input.

The resistors 502 and 505 are set to the same constant, and a voltage corresponding to the difference between the capacitance between the developing sleeve 33 and the antenna power supply 35 and the capacitance of the capacitor 512 is output as the output Vd.

FIG. 6 is a curve showing the relationship between the remaining amount of toner in the nato container 36 and the output Vd.

As shown in the figure, the detection voltage Vd increases as the toner amount decreases. When the detection output = Vd1, it indicates that there is no toner in the toner container 36, and when the detection output = Vd2, it indicates that the toner container 36 is filled with a lot of toner.

As described above, by using the difference between the capacitance between the developing sleeve 33 and the antenna electrode 35 and the capacitance of the capacitor 512 as the detected value of the remaining amount of toner, the influence of the output fluctuation of the developing bias can be suppressed.

The remaining amount detection signal Vd is input to a controller (not shown), and a comparison is made between a remaining amount detection signal previously stored in a memory in the controller and a table showing the relationship between the remaining amount of toner and the remaining amount of toner. The quantity value is determined. Information on the determined remaining toner amount is displayed on the display device 20 on the image forming apparatus main body 1.

As shown in FIGS. 7 and 8, the remaining toner amount is displayed to the user according to which part of the gauge 152 the needle 151 that moves according to the remaining toner amount is displayed. Be informed. In this case, it may be displayed on a terminal screen such as a user's personal computer. Further, as shown in FIG. 9, a display unit such as an LED may be provided in the apparatus main body, and the LED 153 may blink according to the remaining amount of toner.

Next, a series of processing procedures for detecting the remaining amount of toner will be described.

In the image forming apparatus of this embodiment, the toner remaining amount detection processing is performed at the time of starting the recording operation and at the end of the recording operation.

FIG. 10 is a time chart relating to the developing bias and the remaining amount detection signal Vd from the start of the recording operation to the start of the developing process on the first recording paper.

First, the processing at the start of recording will be described.

From the start of the recording operation, a developing bias is output at a predetermined timing. At this time, the AC bias duty (DUTY) is set to 50%, which is a predetermined value at the time of detecting the remaining amount of toner, regardless of the image density setting. Due to the output of the developing bias, the toner remaining amount detection value changes according to the toner remaining amount in the toner container, and becomes saturated at a timing. Further, at a timing, the duty of the AC bias is set to a value corresponding to the image density setting. Here, the duty is set to 70%. Thereafter, the leading end of the first recording sheet reaches the cartridge portion, and the developing process is performed at a predetermined image density. The process of detecting the remaining amount of toner at the start of the recording operation is performed between timings.

Next, the processing at the end of the recording operation will be described with reference to FIG.

After the trailing end of the last recording sheet has passed through the cartridge section, the duty of the developing bias is changed from a value corresponding to the image density, that is, 70%, to a predetermined value 50% at the time of detecting the remaining amount of toner. change. Due to the change in the duty of the AC bias, the toner remaining amount detection value changes and becomes saturated at the timing. Further, the developing bias is turned off at the timing, and the recording operation ends. The process of detecting the remaining amount of toner at the end of the recording operation is performed between timings.

As described above, in the image forming apparatus of this embodiment, the process of detecting the remaining amount of toner is performed by changing the duty of the developing AC bias at the timing when the developing process is not performed at the start and end of recording. Set to a predetermined value at the time of detection and execute. By performing such processing, it is possible to accurately detect the remaining toner amount regardless of the duty setting of the developing AC bias with respect to the image density setting.

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

The basic configuration of the image forming apparatus of this embodiment is the first
This is the same as the embodiment. In the first embodiment, the detection of the remaining amount of toner is performed at the start and end of the recording operation. However, in the present embodiment, the continuous printing operation for continuously performing the recording operation on a plurality of recording sheets is performed. At the time, the toner remaining amount detection process is performed at a time between recording sheets.

FIG. 12 is a time chart of the developing bias and the remaining toner detection value Vd between the recording paper and the next recording paper in the continuous print mode.

First, the recording paper 1 is developed with a predetermined image density setting. Here, the developing AC bias is driven at a duty of 70% to control the image density to a predetermined value. Next, after the trailing end of the recording paper 1 has passed through the cartridge section (timing), the duty of the developing AC bias is set to 50%, which is a predetermined value when the remaining toner amount is detected. By changing the duty of the development AC bias,
The toner remaining amount detection value Vd fluctuates and becomes saturated at the timing. Thereafter, at timing X before the next recording paper 2 reaches the cartridge, the duty setting of the developing AC bias is again set to a value corresponding to the image density setting, that is, 70%.
And the developing process for the recording paper 2 is performed. The process for detecting the remaining amount of toner is performed between timing and timing X.

As described above, in the present embodiment, the process for detecting the remaining amount of toner is performed at the timing when the developing process between the recording sheet and the next recording sheet is not performed. Can be set and executed. By performing such processing, it is possible to accurately detect the remaining toner amount regardless of the duty setting of the developing AC bias with respect to the image density setting.

In the above embodiment, the case where the present invention is applied to the electrophotographic image forming apparatus in which the process cartridge is detachably mounted has been described. However, the developing apparatus fixedly mounted in the electrophotographic image forming apparatus, The present invention is also applicable to an electrophotographic image forming apparatus equipped with the developing device.

[0057]

As is apparent from the above description, according to the developing apparatus, the process cartridge and the electrophotographic image forming apparatus of the present invention, the developing apparatus applies a DC bias from the developing bias applying means to the developer carrier. In this method, an AC bias having an arbitrary duty is applied in a superimposed manner to perform a developing process, wherein the developer remaining amount detecting means includes an electrode provided around the developer container, and the developer remaining amount detecting means is provided between the developer carrier and the electrode. The amount of developer in the developer container is detected by measuring the capacitance of the developer container. The detection of the amount of developer is performed by setting the duty of the AC bias applied to the developer carrier to a predetermined value. By doing so, the developer remaining amount can be accurately detected without affecting the image density.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of an electrophotographic image forming apparatus according to the present invention.

FIG. 2 is a configuration diagram showing one embodiment of a process cartridge according to the present invention.

FIG. 3 is a diagram showing a developing bias generation circuit in a high-voltage power supply.

4A is a waveform diagram of a developing bias when the duty of an AC bias is 50%, and FIG. 4B is a waveform diagram of a developing bias when the duty of an AC bias is 70%.

FIG. 5 is a diagram showing one embodiment of a capacitance detection circuit.

FIG. 6 is a curve showing a relationship between a remaining amount of toner in a nato container and an output Vd.

FIG. 7 is a diagram showing an embodiment of a remaining toner amount display.

FIG. 8 is a diagram showing another embodiment of the toner remaining amount display.

FIG. 9 is a diagram illustrating another example of the remaining toner amount display.

FIG. 10 is a time chart related to a developing bias and a remaining amount detection signal Vd from the start of the printing operation to the start of developing processing on the first printing paper in the first embodiment.

FIG. 11 is a time chart related to a developing bias and a remaining amount detection signal Vd at the end of a recording operation in the first embodiment.

FIG. 12 is a time chart of a developing bias and a toner remaining amount detection value Vd in a continuous print mode in another embodiment.

FIG. 13 is a diagram illustrating a configuration example of a conventional toner remaining amount detection device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic image forming apparatus main body 8 process cartridge 13 photosensitive drum (electrophotographic photosensitive member) 11 scanner unit (latent image forming means) 33 developing sleeve (developer carrier) 34 charging means 35 antenna electrode 36 toner container (developer) Container) 37 Cleaning means 38 High voltage power supply (Developing bias applying means)

Claims (18)

[Claims] 1. An electrophotographic image forming apparatus main body,
A developer container containing a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and a developer carrier for transporting the developer to the electrophotographic photosensitive member; A developer remaining amount detecting unit for detecting an amount of the developer in the developer container, wherein the developing device applies a DC bias and an arbitrary duty to the developer carrier from a developing bias applying unit. A developing method in which an AC bias is applied in a superimposed manner, wherein the developer remaining amount detecting means includes an electrode provided around the developer container, and a capacitance between the developer carrier and the electrode. Is measured to detect the amount of developer in the developer container. The amount of developer is detected by setting the duty of an AC bias applied to the developer carrier to a predetermined value. Developing equipment characterized by Place. 2. The developing device according to claim 1, wherein a density of a developer image formed on said electrophotographic photosensitive member is controlled by adjusting a duty of an AC bias applied to said developer carrier. . 3. The developing device according to claim 1, wherein the detection of the amount of the developer is performed at a timing between a start of a recording operation and a start of a developing process. 4. The developing device according to claim 1, wherein the detection of the amount of the developer is performed at a timing from the end of the developing process to the end of the recording operation. 5. The method according to claim 1, wherein the detection of the amount of the developer is performed at a timing when the developing process is not performed between the recording medium and the next recording medium when the developing process is continuously performed on a plurality of recording media. The developing device according to claim 1, wherein 6. A process cartridge detachable from a main body of an electrophotographic image forming apparatus, comprising: (a) an electrophotographic photosensitive member; and (b) developing for developing an electrostatic latent image formed on the electrophotographic photosensitive member. Containing the agent,
A developing device having a developer container provided with a developer carrier for transporting the developer to the electrophotographic photosensitive member;
(C) a developer remaining amount detecting unit for detecting an amount of the developer in the developer container, and (d) the developing device includes:
In this method, a DC bias and an AC bias having an arbitrary duty are superimposed and applied to the developer carrier from a developing bias applying unit to perform a developing process. The developer remaining amount detecting unit is provided around the developer container. A method of detecting the amount of developer in the developer container by measuring an electrostatic capacity between the developer carrier and the electrode, and detecting the amount of developer by the developer. A process cartridge wherein the duty of an AC bias applied to a carrier is set to a predetermined value. 7. The process cartridge according to claim 6, wherein a density of a developer image formed on said electrophotographic photosensitive member is controlled by adjusting a duty of an AC bias applied to said developer carrier. . 8. The process cartridge according to claim 6, wherein the detection of the amount of the developer is performed at a timing between the start of the recording operation and the start of the developing process. 9. The process cartridge according to claim 6, wherein the detection of the amount of the developer is performed at a timing between the end of the developing process and the end of the recording operation. 10. The method according to claim 1, wherein the detecting of the amount of the developer is performed at a timing when the developing process is not performed between the recording medium and the next recording medium when the developing process is continuously performed on a plurality of recording media. 8. The process cartridge according to claim 6, wherein 11. The process cartridge according to claim 6, further comprising charging means for charging said electrophotographic photosensitive member. 12. The process cartridge according to claim 6, further comprising a cleaning unit for removing a developer attached to the electrophotographic photosensitive member. 13. An electrophotographic image forming apparatus for forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member;
(B) 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. A developing device having a developer container having a developer carrier for housing the developer and transporting the developer to the electrophotographic photosensitive member; and (d) detecting a developer amount in the developer container. (E) the developing device performs a developing process by superimposingly applying a DC bias and an AC bias having an arbitrary duty to the developer carrier from a developing bias applying unit. The developer remaining amount detecting means includes an electrode provided around the developer container, and measures an electrostatic capacity between the developer carrier and the electrode, so that the inside of the developer container is This method detects the amount of developer. Electrophotographic image forming apparatus characterized by performing the duty of the AC bias applied to the carrying member is set to a predetermined value. 14. An electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; and an electrostatic member formed on the electrophotographic photosensitive member. A developing device that contains a developer for developing the latent image and has a developer container having a developer carrier for transporting the developer to the electrophotographic photoreceptor; And (b) a developer remaining amount detecting means for detecting an amount of the developer in the developer container, and (c) the developing device includes a developing bias applying means. A developing method in which a DC bias and an AC bias having an arbitrary duty are applied to the developer carrier in a superimposed manner, and the developer remaining amount detecting means includes an electrode provided around the developer container. It is a method of detecting the amount of developer in the developer container by measuring the capacitance between the developer carrier and the electrode, and detecting the amount of developer is performed by the developer carrier. An electrophotographic image forming apparatus, wherein the duty of an applied AC bias is set to a predetermined value. 15. The method according to claim 13, wherein a density of a developer image formed on said electrophotographic photosensitive member is controlled by adjusting a duty of an AC bias applied to said developer carrier. Electrophotographic image forming apparatus. 16. The electrophotographic image forming apparatus according to claim 13, wherein the detection of the amount of the developer is performed at a timing between the start of the recording operation and the start of the developing process. 17. The electrophotographic image forming apparatus according to claim 13, wherein the detection of the amount of the developer is performed at a timing between the end of the developing process and the end of the recording operation. 18. The method according to claim 18, wherein the detection of the amount of the developer is performed at a timing when the developing process is not performed between the recording medium and the next recording medium when the developing process is continuously performed on a plurality of recording media. 16. The electrophotographic image forming apparatus according to claim 13, 14 or 15.