JP2001075351A - Electrophotographic image forming equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variation in the detection amount of a developer remaining amount or the presence or absence of a developer due to fluctuations in temperature, humidity, and dielectric constant of a developer, and to provide a highly accurate and more preferable developer residue for a user. Provided is an electrophotographic image forming apparatus capable of displaying the amount or the presence or absence of a developer. SOLUTION: An electric signal corresponding to a capacitance Ca between a first electrode and a second electrode of a measurement electrode means 20A, which is generated by applying an AC bias voltage, and an electric signal of a reference electrode means 20B. The remaining amount of the developer in the developer container is calculated based on an electric signal corresponding to a capacitance between the first electrode and the second electrode. This developer remaining amount detection value is corrected based on an electric signal corresponding to the capacitance between the first electrode and the second electrode of the reference electrode means 20B.

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, in particular, a developer remaining amount detecting means capable of sequentially detecting the remaining amount of the developer contained in a developer container, or a developer presence detecting means for detecting the presence or absence of the developer, and further, The present invention relates to an electrophotographic image forming apparatus having a developer amount detecting device provided with both detecting means, and can be particularly suitably embodied in an electrophotographic image forming apparatus provided with a process cartridge.

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.

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 image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is used as an electrophotographic image forming apparatus. A process cartridge system detachable from the main body is employed. According to this process cartridge system, maintenance of the apparatus can be performed by the user himself without relying on a service person, so that operability can be remarkably improved. Therefore, this process cartridge system
It is widely used in electrophotographic image forming apparatuses.

In such an electrophotographic image forming apparatus of the process cartridge type, since the user has to replace the cartridge by himself / herself, a means for notifying the user when the developer is consumed, that is, a developer amount detecting device is used. Required.

More specifically, FIG. 22 shows an example of an image forming apparatus A in which a conventional process cartridge B is mounted. The developing device 9 constituting a developing unit in the process cartridge B has a developer container 9A in which a developer T is stored in a latent image formed on a photosensitive drum 7 as an image carrier.

The developer container 9A contains a photosensitive drum 7
A developing roller 9a, which is a cylindrical developer carrying member that transports the developer T to a developing position facing the developing roller 9a, is disposed in proximity to the photosensitive drum 7, and the developer T is provided on the surface of the developing roller 9a. Is transported to the developing position facing the photosensitive drum 7 by the rotation of the developing roller 9a. The developer T in the developer container 9A is supplied to the developing roller 9a by gravity and a stirring device or other developer conveying means (not shown).

While the developer T is being conveyed, the amount and height of the developer T are restricted by developer regulating means 9d such as a doctor blade, and the developer T is uniformly applied onto the developing roller 9a. In the process of being conveyed to the developing roller, the developing roller 9a, the developer regulating means 9d, or the developer itself is rubbed and charged.

The developer T conveyed to the portion facing the photosensitive drum 7 by the developing roller 9a, that is, to the developing position, is supplied between the photosensitive drum 7 and the developing roller 9a by a developing bias power source as a bias applying means. By the appropriate developing bias voltage applied at 101, the image is transferred onto the photosensitive drum 7, and the electrostatic latent image on the photosensitive drum 7 is developed to form a toner image.

The developer T that has not been subjected to the development is conveyed while remaining on the developing roller 9a, and is again stored in the developing section.

On the other hand, the recording medium P set in the paper feed cassette 2 is conveyed to a transfer position by a pickup roller 3, a pair of conveying rollers, registration rollers (not shown), etc. in synchronization with the formation of the toner image. A transfer roller 4 as a transfer unit is disposed at the transfer position, and transfers a toner image on the photosensitive drum 7 to the recording medium 2 by applying a voltage.

The recording medium P to which the toner image has been transferred is conveyed to the fixing means 5. The fixing unit 5 is a fixing device including a fixing roller 5a having a built-in heater 5b, a driving roller 5c, and the like, and applies heat and pressure to the recording medium P passing therethrough to transfer the toner image transferred onto the recording medium P onto the recording medium P. Establish. Thereafter, the recording medium P is discharged outside the apparatus.

After the transfer roller 4 has transferred the toner image onto the recording medium P, the cleaning device 10 removes the developer remaining on the photoconductor drum 7 and then supplies it to the next image forming process. Is done. The cleaning unit 10 includes an elastic cleaning blade 10 a provided in contact with the photosensitive drum 7.
The remaining residual developer is scraped off and collected in a waste developer reservoir 10b.

As described above, in the developing device 10,
Each time the developing operation is repeatedly performed, the developer T is consumed, and if the developer is insufficient, defects such as a decrease in image density and a missing image occur. For this reason, it is necessary to monitor the presence or absence of the developer T in the developer container 9A at any time so that the developer shortage does not occur.

Therefore, the conventional developing device 9 has a developer amount detecting device as means for detecting the remaining amount of the developer.
The developer amount detection device includes, as electrode means for detecting the remaining amount of the developer T, a rod-shaped developer remaining amount detection antenna electrode 30A horizontally disposed inside the developer container 9A. .

The developer amount detecting device further has a developer amount measuring circuit 50, and this developer amount measuring circuit 50
A capacitance detection circuit 52 as a means for measuring a capacitance between the antenna electrode 30A and the developing roller 9a;
The antenna electrode 30A is connected to the capacitance detection circuit 52. As a result, the developing bias voltage supplied to the developing roller 9a by the developing bias power supply 101 is detected by the antenna electrode 30A, and the antenna electrode 30A is detected.
And the developing roller 9a.

The developer amount measuring circuit 50 includes a reference capacitance 3 as a means for setting a capacitance as a reference for comparison.
0B, and a capacitance detection circuit 51 as a means for measuring the reference capacitance 30B. The reference capacitance 30B and the developing bias power supply 101 are connected, and the reference capacitance 30B
By detecting the developing bias voltage via the interface, an electrostatic capacitance serving as a reference for measuring an unknown electrostatic capacitance is obtained.

The developer amount detecting device includes a capacitance detecting circuit 5
1 is compared with the output of the capacitance detecting circuit 52 of the reference capacitance by a comparing circuit 53 as comparing means to detect the difference, and when the difference is smaller than a predetermined value, the developing is performed. The developer warning circuit 54 determines that the developer has run out, and notifies the user that the developer T is running low.

Since this method has a simple structure and is relatively inexpensive, it is often used in small image forming apparatuses having a process cartridge mounted thereon.

In the detection method described above, it is possible to accurately detect (near-end detection) just before the developer runs out. However, when the supply of the developer means replacement of the process cartridge B as in the case of the process cartridge B, A user who is suddenly informed by the detection signal that the amount of developer is low has to give up printing a large amount unless a spare process cartridge is prepared.

Further, in the image forming apparatus using the above-described method for detecting the remaining amount of the developer, the detection level of the remaining amount of the developer is from 1 to 3 levels, and the conventional circuit has a low detection accuracy. Electrode arrangements with emphasis on detection were forced. Therefore, although the accuracy immediately before the developer is exhausted is high, it is impossible to accurately know the remaining amount of the developer before that.

Furthermore, in recent years, a technology has been developed which can load a large amount of transfer material as a recording medium in an image forming apparatus and print at a high speed, and these devices are used by being shared by a plurality of users via a computer network. Below, the remaining amount of the developer in the process cartridge B is
From now on, it is required to determine whether or not printing is possible for the number of prints to be printed in large quantities.

In other words, the conventional developer remaining amount detection is a fuel warning in a car. Although the minimum number of printed sheets after the warning can be estimated, in the state where the warning is not issued, how much the current developer remaining amount is. It was not in a state where the user could determine whether printing was possible. Therefore, it has been strongly desired to display the remaining amount of the developer with a gas gauge due to the change in the use environment.

That is, the conventional developer amount detecting device detects the presence or absence of the developer in the developer container, that is, detects that the amount of the developer is small immediately before the developer in the developer container is used up. It was only possible, and it was not possible to detect how much developer remained in the developer container.

On the other hand, if the remaining amount of the developer in the developer container can be sequentially detected, the user can know the use condition of the developer in the developer container, and a new process can be performed in accordance with the replacement time. A cartridge can be prepared, which is extremely convenient for the user.

In order to detect the remaining amount of the developer with higher accuracy, the present inventors have developed a detecting means comprising an electrode pair having an electrode pattern formed in a comb or spiral shape on a substrate. It is arranged orthogonally or parallel to the developer carrier, and by measuring the change in the capacitance formed by this electrode pair, the remaining amount of the developer in the developer container is sequentially detected. We have proposed a developing device, a process cartridge and an electrophotographic image forming apparatus which employ an amount detection method.

[0027]

However, according to the results of research conducted by the inventors of the present invention, it has been found that the antenna electrode or the electrode pair detecting means having an electrode pattern formed in the shape of a comb or a spiral. It has been found that the capacitance value is affected by the temperature and humidity, and the capacitance fluctuates. As a result, the presence or absence of the developer or the result of detecting the remaining amount of the developer varies.
Further, it was found that the dielectric constant of the developer itself also fluctuated under the influence of temperature and humidity, and it was difficult to accurately detect the remaining amount of the developer or the presence / absence of the developer.

The present invention relates to further improvements of such a developing device, a process cartridge and an electrophotographic image forming apparatus.

In other words, the main object of the present invention is to suppress variations in the detection result of the remaining amount of the developer or the presence or absence of the developer due to fluctuations in temperature, humidity, and the dielectric constant of the developer, and it is more preferable for a user who has high accuracy. An object of the present invention is to provide an electrophotographic image forming apparatus capable of displaying the remaining amount of developer or the presence / absence of developer.

Another object of the present invention is to provide a special temperature, humidity,
Without providing a means for detecting the dielectric constant of the developer, the detection result of the remaining amount of the developer or the presence / absence of the developer based on the temperature, humidity and the dielectric constant of the developer is corrected. An object of the present invention is to provide an electrophotographic image forming apparatus capable of detecting the remaining amount of developer or the presence / absence of developer.

Another object of the present invention is to provide an electrophotographic image forming apparatus capable of using a developer without causing any adverse effect on an image and without inconvenience to a user. That is.

Still another object of the present invention is to more accurately and accurately detect the state of the developer from a full state to a near-end state immediately before a printing failure even in a developing device or a process cartridge having a long life. It is an object of the present invention to provide an inexpensive electrophotographic image forming apparatus which is provided with a developer amount detecting device having a simple structure and which can further improve the convenience in using the device by a user.

Still another object of the present invention is to provide a device and a process cartridge which can accurately monitor the consumption state of a developer even when used by a plurality of persons or when performing a large-scale print job. It is an object of the present invention to provide an inexpensive electrophotographic image forming apparatus which is provided with a developer amount detecting device capable of accurately grasping the time of replacement of the developer, and which can further improve the convenience of the user when using the device.

[0034]

The above object is achieved by an electrophotographic image forming apparatus according to the present invention. In summary, according to the first aspect of the present invention, in an electrophotographic image forming apparatus for forming an image on a recording medium, (a) an electrophotographic photosensitive member, and (b) an electrophotographic photosensitive member An electrostatic latent image forming means for forming an electrostatic latent image; and (c) a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member. A developer container having a developer carrier for transporting to a photoreceptor, and a first and a second pair of electrodes for sequentially detecting the remaining amount of the developer in contact with the developer in the developer container. (D) a reference electrode means provided with first and second electrodes forming an electrode pair, which is arranged at a position not in contact with the developer, and e) AC bias voltage is applied to the first electrode of the measuring electrode means and the first electrode of the reference electrode means. And (f) the capacitance between the first electrode and the second electrode of the measuring electrode means generated by applying an AC bias voltage to the measuring electrode means. An electrical signal and an electrical signal corresponding to a capacitance between a first electrode and a second electrode of the reference electrode means generated by applying an AC bias voltage to the reference electrode means. Developer remaining amount detection control means for calculating the remaining amount of the developer in the developer container based on the
(G) a developer remaining amount detection value obtained by the developer remaining amount detection control means based on an electric signal corresponding to a capacitance between a first electrode and a second electrode of the reference electrode means; And an electrophotographic image forming apparatus comprising:

According to a second 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 containing a developer for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and a developer carrier for transporting the developer to the electrophotographic photosensitive member,
A developing device having a measuring electrode means for detecting the presence or absence of the developer in contact with the developer in the developer container disposed at a predetermined distance from the developer carrier;
(D) a reference electrode means disposed at a predetermined distance from the developer carrier and not in contact with the developer; and (e) a bias for applying an AC bias voltage to the developer carrier. Applying means for applying an AC bias voltage to the developer carrying member and (f) an electric signal corresponding to a capacitance between the developer carrying member and the measuring electrode means, which is generated by applying an AC bias voltage to the developer carrying member; Developer in the developer container based on an electric signal corresponding to a capacitance between the developer carrier and the reference electrode means, which is generated by applying an AC bias voltage to the developer carrier. (G) the developer presence / absence detection control means for calculating presence / absence of the developer; and (g) the developer presence / absence detection control means based on an electric signal corresponding to a capacitance between the developer carrier and the reference electrode means. Compensate the obtained developer presence / absence detection value. Electrophotographic image forming apparatus characterized by comprising a correction means for, is provided.

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 containing a developer for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and a developer carrier for transporting the developer to the electrophotographic photosensitive member,
A first measuring electrode unit including first and second electrodes forming an electrode pair for sequentially detecting the remaining amount of the developer in contact with the developer in the developer container; and the developer carrier A second measuring electrode means for detecting the presence or absence of the developer by contacting the developer in the developer container arranged at a predetermined distance from the developing device; and (d) the developer. A first reference electrode unit having first and second electrodes forming an electrode pair, and a first reference electrode unit disposed at a predetermined distance from the developer carrier, and contacting the developer; (E) a first electrode of the first measuring electrode means, a first electrode of the first reference electrode means, and A bias applying means for applying an AC bias voltage; and (f) an interface between the bias applying means and the first measuring electrode means. An electrical signal generated by applying a bias voltage between the first electrode and the second electrode of the first measuring electrode means according to the capacitance, and an AC signal applied to the first reference electrode means. An electric signal corresponding to a capacitance between a first electrode and a second electrode of the first reference electrode means, which is generated by applying a bias voltage; A developer remaining amount detection control means for calculating a remaining amount of the developer, (g) the developer carrier generated by applying an AC bias voltage to the developer carrier, and the second measuring electrode means. And an electrostatic signal between the developer carrier and the second reference electrode means, which is generated by applying an AC bias voltage to the developer carrier. The developer volume based on the electrical signal corresponding to A developer presence detection control means for calculating the presence or absence of the developer inside, (h) said first
The developer remaining amount detection value obtained by the developer remaining amount detection control means is corrected based on an electric signal corresponding to the capacitance between the first electrode and the second electrode of the reference electrode means. A first correction unit, and a developer presence / absence detection obtained by the developer presence / absence detection unit based on an electric signal corresponding to a capacitance between the developer carrier and the second reference electrode unit. An electrophotographic image forming apparatus, comprising: a second correcting unit for correcting a value.

According to a fourth aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording medium in which a process cartridge is detachably mountable.
An electrophotographic photosensitive member, and (ii) a developer carrying container for storing a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and transporting the developer to the electrophotographic photosensitive member. A developer container having a body, and a measuring electrode means having first and second electrodes forming an electrode pair for sequentially detecting the remaining amount of the developer in contact with the developer in the developer container. (B) a first electrode and a second electrode which are disposed at a position not in contact with the developer and form an electrode pair. Reference electrode means; (c) bias applying means for applying an AC bias voltage to a first electrode of the measuring electrode means and a first electrode of the reference electrode means; and (d) an AC bias voltage to the measuring electrode means. The measurement caused by applying An electrical signal corresponding to a capacitance between a first electrode and a second electrode of the electrode means, and a first signal of the reference electrode means generated by applying an AC bias voltage to the reference electrode means. A developer remaining amount detection control means for calculating a remaining amount of the developer in the developer container based on an electric signal corresponding to a capacitance between the electrode and the second electrode; (e) A developer remaining amount detection value obtained by the developer remaining amount detection control unit is corrected based on an electric signal corresponding to a capacitance between a first electrode and a second electrode of the reference electrode unit. An electrophotographic image forming apparatus comprising: a correction unit.

According to a fifth aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording medium, wherein the process cartridge is detachable.
An electrophotographic photosensitive member, and (ii) a developer carrying container for storing a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and transporting the developer to the electrophotographic photosensitive member. A developer container having a body, and a measuring electrode means for detecting the presence or absence of the developer by contacting the developer in the developer container arranged at a predetermined distance from the developer carrier. Mounting means for removably mounting a process cartridge having a developing device; and (b) being arranged at a predetermined distance from the developer carrying member and arranged at a position not in contact with the developer. Reference electrode means, and (c)
A bias applying means for applying an AC bias voltage to the developer carrier; and (d) a bias applying means for applying an AC bias voltage to the developer carrier between the developer carrier and the measuring electrode means. An electric signal corresponding to the capacitance and an electric signal corresponding to the capacitance between the developer carrier and the reference electrode means, which are generated by applying an AC bias voltage to the developer carrier. A developer presence / absence detection control means for calculating the presence / absence of the developer in the developer container based on: (e) an electric power corresponding to a capacitance between the developer carrier and the reference electrode means And a correcting means for correcting a developer presence / absence detection value obtained by the developer presence / absence detection control means based on a target signal.

According to a sixth aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording medium, wherein the process cartridge is detachable, wherein (a) (i)
An electrophotographic photosensitive member, and (ii) a developer carrying container for storing a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and transporting the developer to the electrophotographic photosensitive member. A first measurement comprising a developer container having a body and first and second electrodes forming an electrode pair for sequentially detecting the remaining amount of the developer in contact with the developer in the developer container Electrode means, and second measuring electrode means for detecting the presence or absence of the developer by contacting the developer in the developer container disposed at a predetermined distance from the developer carrier. A developing device;
Mounting means for removably mounting a process cartridge having: (b) first reference electrode means disposed at a position not in contact with the developer and having first and second electrodes forming an electrode pair; A second reference electrode means disposed at a predetermined distance from the developer carrier and not in contact with the developer; and (c) a first electrode of the first measurement electrode means. And a bias applying means for applying an AC bias voltage to the first electrode of the first reference electrode means and the developer carrier; and (d) applying an AC bias voltage to the first measuring electrode means. Applying an AC bias voltage to the first reference electrode means and an electric signal corresponding to a capacitance between a first electrode and a second electrode of the first measurement electrode means generated by the first reference electrode means. Caused by the first A remaining amount of developer for calculating a remaining amount of the developer in the developer container based on an electric signal corresponding to a capacitance between the first electrode and the second electrode of the quasi-electrode means; Control means; and (e) an electric signal generated by applying an AC bias voltage to the developer carrier and corresponding to an electrostatic capacitance between the developer carrier and the second measuring electrode means. Developing the developer based on an electric signal generated by applying an AC bias voltage to the developer carrier and corresponding to a capacitance between the developer carrier and the second reference electrode means. A developer presence / absence detection control means for calculating the presence / absence of the developer in the developer container; and (f) electricity corresponding to the capacitance between the first electrode and the second electrode of the first reference electrode means. The developer remaining amount detection value obtained by the developer remaining amount detection control means is corrected based on the target signal. A first correction unit, and a developer presence / absence detection obtained by the developer presence / absence detection unit based on an electric signal corresponding to a capacitance between the developer carrier and the second reference electrode unit. An electrophotographic image forming apparatus, comprising: a second correcting unit for correcting a value.

According to one embodiment of the present invention, the first electrode and the second electrode of the measuring electrode means and the reference electrode means are formed in a comb-like or spiral manner. You. According to another embodiment, the measurement electrode means and the reference electrode means are antenna electrodes arranged at a predetermined interval with respect to the developer carrier.

According to another embodiment of the present invention, the first
The first electrode and the second electrode of the first measuring electrode means and the first reference electrode means are formed in combination with each other in a comb shape or a spiral shape, and the second measuring electrode means and the second The reference electrode means is an antenna electrode arranged at a predetermined interval with respect to the developer carrier.

According to another embodiment of the present invention, the first
And a second correction unit that generates a correction signal corresponding to a change in the dielectric constant due to the temperature and humidity of the developer.

According to another embodiment of the present invention, the first
And the second correction means can be the same correction means.

According to still another embodiment of the present invention, the bias applying means may be a developing bias applying means.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrophotographic image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 First, an embodiment of an electrophotographic image forming apparatus to which a process cartridge constructed according to the present invention can be mounted will be described with reference to FIGS. In this embodiment, the electrophotographic image forming apparatus is an electrophotographic laser beam printer A, which forms an image on a recording medium, for example, a recording paper, an OHP sheet, a cloth, or the like by an electrophotographic image forming process. is there.

The laser beam printer A has a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum 7. The photoreceptor drum 7 is charged by a charging roller 8 serving as a charging unit, and then is converted into image information from an optical unit 1 having a semiconductor laser 1a as a light source, a rotating polygon mirror 1c rotated by a scanner motor 1b, and a reflecting mirror 1d. By irradiating the corresponding laser beam, a latent image corresponding to the image information is formed on the photosensitive drum 7. This latent image is developed by the developing means 9 to become a visible image, that is, a toner image.

That is, the developing means 9 has a developer container provided with a developing roller 9a as a developer carrier.
The developing roller 9a has a built-in fixed magnet 9c.
The developer is conveyed by rotating the developing roller 9 a, is supplied with triboelectric charge by the developing blade 9 d, forms a developer layer having a predetermined thickness, and is supplied to the developing area of the photosensitive drum 7. The developer supplied to the developing area is transferred to a latent image on the photosensitive drum 7 to form a toner image. The developing roller 9a is connected to a developing bias circuit, and is usually applied with a developing bias voltage in which a DC voltage is superimposed on an AC voltage.

On the other hand, a recording medium P, such as plain paper, set in the paper feed cassette 2a in synchronism with the formation of the toner image, is sent out to the transport path by the paper feed roller 3a. The recording medium P sent to the transport path is transported by a pair of transport rollers 6a and 6b.
The sheet is conveyed to the transfer position by the pre-transfer roller pair 6c.
A transfer roller 4 as a transfer unit is disposed at the transfer position, and transfers a toner image on the photosensitive drum 7 to the recording medium P by applying a voltage.

The recording medium P to which the toner image has been transferred is conveyed to the fixing means 5. The fixing unit 5 includes a fixing roller 5a having a built-in heater 5b and a driving roller 5c, and applies heat and pressure to the recording medium P passing therethrough to fix the transferred toner image on the recording medium P.

The fixed recording medium P is transferred to a discharge roller pair 6.
By d, the sheet is discharged to a discharge tray 11 provided on the upper surface of the apparatus main body of the laser beam printer A.

The printer A of this embodiment has a single-sided image forming (single-sided printing) mode and a double-sided image forming (double-sided printing) mode as image forming modes, and operates a swingable flapper 6e. The transport destination of the printed recording medium P can be switched to the discharge tray 11 or the double-sided image forming unit 12. The recording medium P transported to the double-sided image forming unit 12 is transported by the transport rollers 6.
It is conveyed to a reversing part at f. The recording medium P conveyed to the reversing unit is turned forward / reversely by the reversing roller 6g sequentially, thereby reversing the recording medium P and returning it to the re-feeding unit. The recording medium P in the sheet re-feeding section is fed again by a sheet re-feeding roller 6h into a conveying path provided with a pair of conveying rollers 6a and 6b.

In this embodiment, in addition to the paper feed cassette 2a, an optional paper feed roller 3b which is detachable and has a function of identifying the size of the recording medium P and feeds the recording medium P to the conveyance path is provided. Paper feed cassette 2b, a manual paper feed port 2c provided with a manual paper feed roller 3c for feeding the recording medium P to the transport path, a paper feed roller for detachable and capable of loading only envelopes, and for feeding envelopes one by one to the transport path. An envelope feeder 2d having 3d is further provided.

According to the present embodiment, a pre-feed sensor 13 for detecting the leading end and the trailing end of the recording medium P fed from a source other than the envelope feeder 2d is provided in the conveying path of the recording medium P.
a, the image writing (recording / printing) on the photosensitive drum 7 and the conveyance of the recording medium are synchronized with respect to the fed recording medium P, and the length of the fed recording medium P in the conveyance direction is set to A top sensor 13b for measurement, a paper ejection sensor 13c for detecting the presence or absence of the fixed recording medium P, a reversing sensor 13d for detecting the front / rear end of the recording medium P conveyed to the reversing unit, A refeed sensor 13e for detecting the presence or absence of the recording medium P in the refeed section is provided.

After the transfer of the toner image onto the recording medium P by the transfer roller 4, the developer remaining on the photosensitive drum 7 is removed by the cleaning unit 10, and then subjected to the next image forming process. Is done. The cleaning unit 10 includes an elastic cleaning blade 10 a provided in contact with the photosensitive drum 7.
The remaining residual developer is scraped off and collected in a waste developer reservoir 10b.

FIG. 2 is a block diagram of a circuit configuration of a control system for controlling each of the mechanism units having the above configuration. 2, the control system 200 includes a printer controller 201 and an engine control unit 202. The printer controller 201 expands image code data sent from an external device such as a host computer into bit data necessary for printing by a printer, reads internal information of the printer, and displays it. The printer engine control unit 202 controls the operation of each unit of the printer engine in accordance with an instruction from the printer controller 201 and notifies the printer controller 201 of printer internal information. Further, a signal from each sensor is input to the engine control unit 202 via a sensor input unit 206.

The control system 200 further includes a paper transport control unit 20 for driving / stopping a motor and rollers for transporting the recording medium in accordance with an instruction from the printer engine control unit 202.
3, a high-voltage control unit 204 that performs output control of each high voltage in each step such as charging, development, and transfer in accordance with an instruction from the printer engine control unit 202, and a driving / stopping of a scanner motor and lighting of a laser beam by the engine control unit 202. An optical system control unit 205 that controls according to the instruction, and a fixing unit temperature control unit 207 that adjusts the temperature of the fixing unit to the temperature specified by the printer engine control unit 202 are provided. The control system further drives / stops the drive system according to an instruction from the printer engine control unit 202, and determines whether or not a recording medium is present.
A detachable optional cassette control unit 208 that notifies the printer engine control unit 202 of paper size information,
A detachable double-sided unit control unit 209 for performing a reversing and refeeding operation of a recording medium in accordance with an instruction of the printer engine control unit 202 and notifying the operation state to the printer engine control unit 202; A detachable envelope feeder control unit 2 that drives / stops a drive system according to an instruction from the control unit 202 and notifies the printer engine control unit 202 of the presence / absence of a recording medium.
And 10.

On the other hand, in the present embodiment, as shown in FIG. 1, the process cartridge B includes a developer container (developer accommodating portion) 9A for accommodating a developer, a developing roller 9a and a developing blade 9d. The developing unit is formed integrally with the means 9, and the developing unit is further provided with the photosensitive drum 7,
Cleaning means 1 such as cleaning blade 10a
The cartridge is formed by attaching the charging roller 8 and the charging roller 8 and integrally connecting them.

The process cartridge B is removably mounted by a user on a cartridge mounting means 40 provided in the main body of the image forming apparatus.

According to the present invention, the process cartridge B
Is provided with a developer amount detecting device capable of sequentially detecting the remaining amount according to consumption of the developer in the developer container 9A. FIG. 3 shows the overall schematic configuration of the developer amount detecting device. According to the present embodiment, the developer amount detecting device has a developer remaining amount detecting means 100A.

The developer remaining amount detecting means 100A includes a measuring electrode means 20A for detecting the amount of developer, a reference electrode means 20B for outputting a reference signal, and a measuring electrode means 20A.
And a reference electrode means 20B. According to the present invention, the developer remaining amount detection circuit 100 includes the measuring electrode unit 20A and the reference electrode unit 2.
A control circuit 102a as a developer remaining amount detection control means for calculating a developer remaining amount based on an electric signal from 0B;
Further, a detection level reference voltage circuit 120a is connected to the reference electrode means 20B and serves as a correction means for inputting a signal for correcting a change in the dielectric constant due to the temperature and humidity of the developer to the developer remaining amount detection control circuit 102a. Have.

As shown in FIG. 6, for example, the measuring electrode means 20A is located at a position in contact with the developer, such as the inner side surface or the bottom surface of the developer container 9A of the developing means 9, and the developer is reduced. As a result, they are arranged in such a direction that the contact area with the developer varies.

As shown in FIG. 7, the measuring electrode means 20A includes a pair of electrodes, ie, an input electrode 23 and an output electrode 24, which form a pair of electrodes formed in parallel on a substrate 22 at predetermined intervals. Have. In this embodiment, the electrodes 23, 2
4 has at least a pair of electrode portions 23a to 23f, 24a to 24f arranged in parallel at a predetermined interval G, and the respective electrode portions 23a to 23f, 24a to 24f are mutually connected at the connection electrode portions 23g, 24g. The two electrodes 23 and 24 are connected to each other and have a large number of uneven shapes combined with each other, that is, a comb-like shape. Of course, the electrode pattern of the measurement electrode means 20A is not limited to this, and a pair of electrodes 23 and 24 are formed in a spiral shape arranged in parallel at a predetermined interval from each other as shown in FIG. Can also.

The measuring electrode means 20A is a pair of parallel electrodes 2
By measuring the capacitance between 3 and 24, the remaining amount of the developer in the developer container 9A can be sequentially detected. That is, since the developer has a higher dielectric constant than air, the electrostatic capacity between the pair of electrodes 23 and 24 increases when the developer comes into contact with the surface of the measurement electrode unit 20A.

The electrode patterns 23 and 24 of the measuring electrode means 20A are, for example, a hard printed board 22 of, for example, paper phenol or glass epoxy having a thickness of 0.4 to 1.6 mm, or a thickness of about 0.1 mm. Polyester,
Conductive metal patterns 23, 2 such as copper are etched or printed on a flexible printed circuit board 22 such as polyimide.
4 and can be manufactured by the same method as the usual method for forming a wiring pattern on a printed circuit board. Therefore, even a complicated electrode pattern shape as shown in FIGS. 7 and 8 can be easily manufactured, and the manufacturing cost is almost the same as that of a simple pattern.

Also, by using a complicated pattern shape as shown in FIGS. 7 and 8, the facing length between the electrodes 23 and 24 can be lengthened, and further by using a pattern forming method such as etching. It is also possible to reduce the gap G between the two to about several tens of μm, and it is possible to obtain a large capacitance. Further, the amount of change in the capacitance can be increased, and the detection accuracy can be increased.
Specifically, the electrodes 23 and 24 have a width of 0.1 to 0.5 m.
m, a thickness of 17.5 to 70 μm, and an interval G of 0.5 μm.
1 to 0.5 mm. Further, the metal pattern formation surface can be laminated with a thin resin film of, for example, about 12.5 to 125 μm.

As described above, according to the developer amount detecting device of the present invention, the measuring electrode means 20A provided in the direction in which the amount of the developer on the side or bottom inside the developer container 9A is reduced.
The change in the contact area of the developer with respect to, that is, the change in the capacitance of the measuring electrode means 20A is measured, and the developer amount of the entire developer container is sequentially detected based on the measured value.

That is, since the dielectric constant of the developer is higher than air, the portion where the developer is in contact with the measuring electrode means 20A (the portion with the developer) is the portion where the developer is not in contact (the portion without the developer). The output capacitance is large as compared with. Therefore, if the change in the capacitance is measured, the developer container 11
The developer amount in A can be estimated.

According to the present embodiment, the developer remaining amount detecting means 1
00A reference electrode means 20B
The configuration is the same as that of A, and the temperature and humidity characteristics show the same characteristics. The reference electrode means 20B is arranged at a position where it does not come into contact with the developer.

According to this embodiment, as will be understood with reference to FIGS. 9 and 10, the measuring electrode means 20A and the reference electrode means 20B are formed of a single bendable substrate 22 such as a flexible printed circuit board. Each electrode 23, 2 on one side
4 can be formed and folded back to be disposed in the developer container 9A. In this embodiment, the measuring electrode means 20A
The reference electrode means 20B has the same electrode pattern.
That is, the patterns of the electrodes 23 and 24 of the measurement electrode means 20A and the reference electrode means 20B have a pattern shape in which the capacitance is substantially equal and the pattern width, length, interval, and facing area are substantially equal. The reference electrode means 20B manufactured in this manner is folded at substantially the center of the substrate, and the developer container 11A in which the measurement electrode means 20A is disposed.
Is arranged in a portion which is not in contact with the developer and is partitioned by the partition wall 21.

As described above, the measuring electrode means 20A and the reference electrode means 20B are manufactured in the same manner as in a normal printed circuit board manufacturing process. This causes variations in the capacitance of the substrate due to variations in the electrode pattern width and height. In this embodiment, since the measurement electrode means 20A and the reference electrode means 20B are formed on the same surface of the substrate, one substrate serves as the detection member and the comparison member. Can be cheaper.
Further, since the electrode pattern is formed on the same material, the variation due to the difference in the base material can be suppressed. Further, since the pattern is formed on the same surface, the variation at the time of pattern formation such as etching can be suppressed. Further, with the above configuration, the detection pattern can be arranged up to the upper portion of the developer container, and therefore, the developer amount can be measured from a state where the developer is almost full in the developer container. .

In the description of the above embodiment, the measuring electrode means 20
The pattern of the two electrodes 23 and 24 of the A and reference electrode means 20B has been described as having a pattern shape having substantially the same capacitance and substantially the same pattern width, length, interval and facing area. Electrode means 20B for
The area of the electrode patterns 23 and 24 is measured by the measuring electrode means 20A.
It is also possible to make the area of the electrode patterns 23 and 24 different from each other. In this case, the output of the reference electrode means 20B is converted into an output multiplied by a predetermined coefficient, and the converted output is compared with the output of the measurement electrode means 20A. With such a configuration, the reference electrode means 20B can be made smaller, so that the space for disposing the detecting member can be reduced. Alternatively, both members 20A and 20B may be provided on the same wall surface on the same side of the developer container 9A, and the reference electrode means 20B may be partitioned so as not to contact the developer.
In this case, it is possible to increase the ratio of the pattern on the detection member 20A side within a limited area, and it is possible to increase the amount of change in capacitance and the accuracy.

As described above, the reference electrode means 2 having the above configuration
OB changes its capacitance depending on environmental conditions such as temperature and humidity, and functions as a reference comparison member for the measurement electrode means 20A. The output of the measuring electrode means 20A is compared with the output of the reference electrode means 20B which fluctuates due to changes in the environment. For example, the predetermined capacitance of the reference electrode means 20B is set to the same value as the measurement electrode means 20A when there is no developer, and the difference between the output of the reference electrode means 20B and the output of the measurement electrode means 20A is obtained. Since it is possible to obtain an output corresponding to only the change in the capacitance, it is possible to improve the accuracy of detecting the remaining amount of the developer.

The principle of detecting the amount of developer using the reference electrode means 20B of the present embodiment will be further described. The measuring electrode means 20A measures the electrostatic capacity of the contact portion on the pattern surface to measure the developing capacity in the developer container 9A. Because we estimate the dosage,
The value fluctuates due to changes in the environment (humidity, temperature, etc.).

For example, when the humidity increases, the amount of water vapor in the air increases.
The dielectric constant of the atmosphere touching also increases. Therefore, if the environment changes even when the amount of developer is the same, the measuring electrode means 20A
The output from will also change. Further, if the material of the substrate 22 on which the pattern is formed also absorbs moisture, the dielectric constant changes due to the moisture absorption, so that the environment changes.

For this reason, the reference electrode means 20B as a comparison member which has the same environmental fluctuation as the measurement electrode means 20A, ie,
For example, a reference electrode unit 20B having the same configuration as the measurement electrode unit 20A and having a configuration not in contact with the developer is placed under the same environment as the measurement electrode unit 20A, and both outputs are compared to obtain a difference. By canceling the fluctuation, the remaining amount of the developer can be measured without being affected by the environmental fluctuation.

As shown in the leftmost bar graph in FIG. 11, the capacitance measured from the measuring electrode means 20A, which is a detecting member for detecting the amount of developer, depends on the developer in contact with the surface of the detecting member. The environmental fluctuation is added to the fluctuation and output. Then, when it is moved to a high-temperature and high-humidity environment, the variation due to the developer does not change as shown in the leftmost bar graph in FIG. Despite this, the capacitance increases.

Therefore, as shown in the central bar graphs of FIGS. 11 and 12, a reference electrode means (comparative member) 20B having the same environmental fluctuation as the measuring electrode means (detecting member) 20A is arranged, and the difference (right bar graph) is shown. Thus, only the capacitance due to the developer can be measured.

According to the present embodiment, as described above, as shown in FIGS. 9 and 10, the developer container 9 of the developing means 9 is provided.
A is provided with a measuring electrode unit 20A and a reference electrode unit 20B having the same configuration as the measuring electrode unit 20A for comparison. In this configuration, since the developer container 9A has the measurement electrode means 20A and the reference electrode means 20B, fluctuations due to the environment can be canceled, and the measurement electrode means 20A and the reference electrode means 20B are placed under substantially the same environment. Therefore, the detection accuracy can be increased.

Next, the developer amount detecting device according to the present invention will be further described with reference to FIGS. FIG. 3 shows an overall configuration of a developer amount detecting device provided with a developer remaining amount detecting unit 100A, and FIG. 4 shows a specific circuit diagram of the developer remaining amount detecting circuit 100.

The developer amount detecting device of this embodiment has a developing bias circuit 101 as a developing bias applying means for applying a developing bias voltage to the developing roller 9a.
As the developing bias voltage, a voltage obtained by superimposing a DC voltage on an AC voltage is usually used.

The developing bias circuit 101 includes a developing roller 9
a, and is connected to the control circuit 102a of the developer remaining amount detection circuit 100 via the measurement electrode means 20A and the reference electrode means 20B. The reference electrode means 20B functions as a capacitance element having a predetermined capacitance Cb, that is, functions as an impedance element.

That is, the measuring electrode means 20A as a detecting member having a capacitance Ca which varies according to the amount of the developer,
And a reference electrode unit 20B as a comparison member having a capacitance Cb, one input side electrode of the reference electrode unit 20B is connected to a developing bias circuit 101 as a developing bias applying unit, and the other output side electrode is a developer. It is connected to the remaining amount detection control circuit 102a. The output side electrode of the reference electrode means 20B is also connected to the detection level reference voltage circuit 120a of the developer amount detection circuit 100, and the output of the detection level reference voltage circuit 120a is input to the control circuit 102a.

The reference electrode means 20B uses the AC (alternating current) I11 to generate a reference voltage V for detecting the remaining amount of the developer.
11 is set. That is, the developer remaining amount detection circuit 100
As shown in FIG. 4, the reference electrode means 20B, that is, the AC current I11 applied to the impedance element and the resistance R10
Is added to V2 set by the resistors R11 and R12 to determine the reference voltage V11.

Therefore, the AC (alternating current) I12 applied to the measuring electrode means 20A is input to the amplifier circuit 103, and the detection value V12 of the remaining amount of the developer (= V11-I12 × R
Output as 1).

With the above configuration provided with the reference electrode means 20B, the same capacitance (ΔC) as the capacitance value ΔCa of the measurement electrode means 20A changed by the temperature and humidity characteristics is obtained.
0B, so that the measuring electrode means 20A
Is corrected.

As described above, the reference electrode means 20B functions as an element for detecting the temperature and humidity inside the cartridge and also functions as an element for correcting a change in the dielectric constant due to the dielectric constant of the developer.

Therefore, the detection level reference voltage V13 is output by the detection level reference voltage circuit 120a with the change of the reference voltage V11 which is the output voltage from the reference electrode means 20B, and the measured value is corrected. As a result, it is possible to detect the remaining amount of the developer without the influence of the dielectric constant of the developer which fluctuates depending on the temperature and the humidity.

FIG. 5 is a flowchart for explaining one embodiment of the method for detecting the remaining amount of the developer according to the present invention. The method for detecting the remaining amount of the developer according to the present invention will be described with reference to FIGS.

In the present invention, the developer amount detection value V12 detected by the developer remaining amount detection circuit 100 and the detection level reference voltage V1 detected by the detection level reference voltage circuit 120a are used.
3, the remaining amount of developer is corrected and calculated by a remaining amount detection control circuit 102a in the CPU. That is, the CPU of the control circuit 102a is provided with a table for calculating the remaining amount of the developer from the detected value V12 and the detected level reference voltage V13.
A developing bias is applied, and a detection value, that is, a detection voltage V12
The calculation of the remaining amount of the developer is started at the timing when is output.

More specifically, there is provided a table for calculating the detection level reference voltage V13 from the value of the reference voltage V11. At the same time when the control circuit 102a detects the developer remaining amount detection value V12, the detection level reference voltage circuit 120a Detects the reference voltage V11 and then outputs the reference voltage V1.
1, the temperature and humidity are calculated, and the detection level reference voltage V13 is calculated based on the calculated values. Then, as described above,
The control circuit 102a controls the detected remaining amount of developer V12
And the remaining developer amount is calculated based on the detection level reference voltage V13 from the detection level reference voltage circuit 120a.

At the time when this series of detection of the remaining amount of the developer is completed, the remaining amount of the developer present in the cartridge is calculated.

By performing such processing, it is possible to detect the remaining amount of the developer stably without being affected by the change in the capacitance of the electrode due to the influence of the temperature and humidity and the change in the dielectric constant of the developer.

In this embodiment, the impedance element, that is, the reference electrode means 20B is provided inside the cartridge. However, even when the impedance element is provided outside the cartridge, the same processing can be performed to detect the remaining amount of the developer. It is possible.

In this embodiment, the developer remaining amount detecting means 1
Developing bias circuit 10 as a driving bias voltage of
Although the output from 1 has been used, the present invention is not limited to this, and any bias voltage applying means may be used.

According to the image forming apparatus of the present invention, as described above, the amount of the developer in the developer container 9A is sequentially detected, and the consumption of the developer is displayed based on the information. Accordingly, it is possible to prompt the user to prepare the developer replenishment cartridge, and further to prompt the user to replenish the developer based on the developer end detection information.

A method of displaying the amount of developer will be described. For example, information detected by the above-described developer amount detecting device is displayed on a terminal screen of a user's personal computer or the like in FIGS.
Is displayed as shown. 13 and 14, the user is notified of the amount of developer based on which part of the gauge 42 the needle 41 that moves according to the amount of developer is pointing.

As shown in FIG. 15, a display unit such as an LED may be provided directly on the main body of the electrophotographic image forming apparatus, and the LED 43 may be turned on and off according to the amount of the developer.

Embodiment 2 FIGS. 16 and 17 show another embodiment of the developer amount detecting device according to the present invention. The developer amount detecting device of this embodiment can also be suitably used in the electrophotographic laser beam printer A shown in FIGS. 1 and 2 described in the first embodiment. Therefore, the description of the laser beam printer A is omitted, and the developer amount detecting device will be described below.

In this embodiment, the developer amount detecting device has a developer presence / absence detecting means for detecting the toner end of the developer in the developer container. FIG. 16 shows the developer presence detecting means 11.
FIG. 1 shows the overall configuration of a developer amount detecting device provided with 0A, and FIG.
7 shows a specific circuit diagram of the developer presence / absence detection circuit 110.

The developer amount detecting device of this embodiment has a developing bias circuit 101 as a developing bias applying means for applying a developing bias voltage to the developing roller 9a.
As the developing bias voltage, a voltage obtained by superimposing a DC voltage on an AC voltage is usually used.

According to the present embodiment, the measuring electrode means 20A and the reference electrode means 20B are electrodes composed of antenna rods installed in the cartridge.
Both A and 20B are provided at a predetermined distance from the developing roller 9a along the longitudinal axis direction of the developing roller 9a. The measurement antenna electrode 20A is arranged at a position where it contacts the developer, and the reference antenna electrode 20B is arranged at a position where it does not contact the developer.

A measuring electrode means 20A as a detecting member having a capacitance Ca which varies according to the amount of developer between the developing roller 9a and a comparison having a predetermined capacitance Cb between the developing roller 9a. Reference electrode means 20B as a member
Are control circuits 1 of the developer presence / absence detection circuit 110, respectively.
02b. The reference electrode means 20B is provided with a detection level reference voltage circuit 120 of the developer presence / absence detection circuit 110.
b, and the output of the detection level reference voltage circuit 120b is input to the developer presence / absence detection control circuit 102b.

The reference electrode means 20B uses the AC (alternating current) I21 to generate a reference voltage V for detecting the presence or absence of the developer.
21 is set. That is, the developer presence / absence detection circuit 110
As shown in FIG. 17, the reference electrode means 20B, that is, the AC current I21 applied to the impedance element and the resistance R1
The reference voltage V21 is determined by adding the voltage drop V1 generated at 0 to V2 set by the resistors R11 and R12.

As described above, the measurement antenna electrodes 20A are arranged at predetermined intervals on the developing roller 9a so as to face each other, and are connected to the control circuit 102b as the developer capacity Ca. Accordingly, an AC (alternating current) I22 applied to the developer capacitance Ca between the developing roller 9a and the measurement antenna electrode 20A is applied to the amplifier circuit 103, and the detection value V22 (= V21-I22 × R2).

With the above-described configuration provided with the reference electrode means 20B, the same capacitance (ΔC) as the capacitance value ΔCa of the measurement electrode means 20A changed by the temperature and humidity characteristics is obtained.
0B, so that the measuring electrode means 20A
Is corrected.

As described above, the reference electrode means, that is, the reference antenna electrode 20B is used to control the temperature inside the cartridge,
In addition to functioning as an element for detecting humidity, it also functions as an element for correcting a change in the dielectric constant due to the dielectric constant of the developer.

Therefore, with the change of the reference voltage V21, which is the output voltage from the reference antenna electrode 20B, the detection level reference voltage V2 is output by the detection level reference voltage circuit 120b.
3 is output to correct the measured value. This allows the temperature,
The presence / absence of the developer can be detected without the influence of the dielectric constant of the developer which varies with humidity.

FIG. 18 is a flowchart for explaining an embodiment of the method for detecting the remaining amount of the developer according to the present invention. FIG.
The developer remaining amount detecting method according to the present invention will be described with reference to FIGS.

In the present invention, the developer presence / absence detection value V22 detected by the developer presence / absence detection circuit 110 and the detection level reference voltage V2 detected by the detection level reference voltage circuit 120b are used.
23, the developer presence / absence detection control circuit 102b corrects and calculates the presence / absence of the developer. That is, the CPU of the control circuit 102b is provided with a control formula for calculating the presence or absence of the developer according to the detected detection value V22 and the detection level reference voltage V23. The calculation of the presence or absence of the developer is started at the timing when the detection voltage V22 is output.

More specifically, at the same time that the control circuit 102b detects the developer presence / absence detection value V22, the detection level reference voltage circuit 120b detects the reference voltage V21, and calculates the temperature and humidity from the reference voltage V21. , The detection level reference voltage V23 is calculated based on the calculated value.

The control circuit 102b calculates the presence or absence of the developer based on the detected developer presence / absence detection value V22 and the detection level reference voltage V23 from the detection level reference voltage circuit 120b.

When this series of detection of the presence or absence of the developer is completed, the presence or absence of the developer present in the cartridge is calculated.

By performing such processing, stable detection of the presence or absence of the developer can be performed without being affected by changes in the capacitance of the electrode and changes in the dielectric constant of the developer due to the influence of temperature and humidity.

In this embodiment, the impedance element, that is, the reference electrode means 20B is provided inside the cartridge. However, even when the impedance element is provided outside the cartridge, the same processing can be performed to detect the remaining amount of the developer. It is possible.

Further, in this embodiment, the output from the developing bias circuit is used as the driving bias of the developer remaining amount detecting means. However, the present invention is not limited to this, and any bias power supply may be used.

According to the image forming apparatus of the present invention, as described above, the amount of the developer in the developer container 9A is sequentially detected, and the presence or absence of the developer is displayed based on the information. The developer replenishment can be prompted by the developer end detection information.

Embodiment 3 FIGS. 19 and 20 show another embodiment of the developer amount detecting device according to the present invention. The developer amount detection device of this embodiment is also used in the electrophotographic laser beam printer A shown in FIGS. 1 and 2 described in the first embodiment. Therefore, the description of the laser beam printer A is omitted, and the developer amount detecting device will be described below.

The developer amount detecting apparatus according to the present embodiment is characterized by including a developer remaining amount detecting means 100A and a developer presence detecting means 110A.

FIG. 19 shows the entire configuration of the developer amount detecting device, and FIG. 20 shows a specific circuit diagram of the developer remaining amount detecting circuit 100 and the developer presence detecting circuit 110.

The developer amount detecting device of this embodiment has a developing bias circuit 101 as a developing bias applying means for applying a developing bias voltage to the developing roller 9a.
As the developing bias voltage, a voltage obtained by superimposing a DC voltage on an AC voltage is usually used.

According to this embodiment, as in the case of the first embodiment shown in FIG. 9 and FIG.
Has a measuring electrode means 20A1 and a reference electrode means 20B1, and has a measuring electrode means 20A1 and a reference electrode means 20B1.
Each of the electrodes 23 and 24 is formed on one surface of a single bendable substrate 22 such as a flexible printed circuit board,
It is folded back and placed in the developer container 9A. Also in the present embodiment, the measurement electrode means 20A1 and the reference electrode means 20B1 have the same electrode pattern, though not limited thereto. That is, the patterns of the electrodes 23 and 24 of the measurement electrode unit 20A1 and the reference electrode unit 20B1 have a pattern shape in which the capacitance is substantially equal and the pattern width, length, interval, and facing area are substantially equal. The reference electrode unit 20B1 manufactured in this manner is folded substantially at the center of the substrate, and is partitioned by the partition wall 21 inside the developer container 11A in which the measurement electrode unit 20A1 is disposed. It is arranged at a place that does not come into contact with the developer.

The developing bias circuit 101 includes the developing roller 9
a, and is connected to the control circuit 102a of the developer remaining amount detection circuit 100 via the measurement electrode means 20A1 and the reference electrode means 20B1. In this embodiment, the reference electrode means 20B1 is a capacitance element having a predetermined capacitance Cb, that is, an impedance element.

That is, the measuring electrode means 20A as a detecting member having the capacitance Ca1 which varies according to the amount of the developer.
1 and a reference electrode means 20B1 as a comparison member having a capacitance Cb1, one input side electrode of which is connected to a developing bias circuit 1 as a developing bias applying means.
01, and the other output side electrode is connected to the control circuit 102a of the developer remaining amount detection circuit 100. The output side electrode of the reference electrode means 20B1 is connected to the detection level reference voltage circuit 120a of the developer remaining amount detection circuit 100,
The output of the detection level reference voltage circuit 120a is input to the developer remaining amount detection control circuit 102a.

The reference electrode means 20B1 uses the AC (alternating current) I31 to set a reference voltage V31 for detecting the remaining amount of the developer. That is, the control circuit 102a
As shown in (2), the reference voltage V31 is determined by adding the AC current I31 applied to the impedance element and the voltage drop V1 generated by the resistor R10 to V2 set by the resistors R11 and R12. ing.

Accordingly, the AC (alternating current) I32 applied to the measuring electrode means 20A1 is input to the amplifier circuit 103a, and the detection value V32 (= V31-I32 ×
R3).

With the above-described structure provided with the reference electrode means 20B1, the measurement electrode means 20A changed by the temperature and humidity characteristics.
The same capacitance (ΔC) as the capacitance value ΔCa of 1 also changes in the reference electrode means 20B1, and as a result, the measured value of the measurement electrode means 20A1 is corrected.

As described above, the reference electrode means 20B1 functions not only as an element for detecting the temperature and humidity inside the cartridge but also as an element for correcting a change in the dielectric constant due to the dielectric constant of the developer.

Therefore, the detection level reference voltage V33 is changed by the detection level reference voltage circuit 120a in accordance with the change of the reference voltage V31 which is the output voltage from the reference electrode means 20B1.
Is output to correct the measured value. As a result, it is possible to detect the remaining amount of the developer without the influence of the dielectric constant of the developer which fluctuates depending on the temperature and the humidity.

FIG. 21 is a flowchart for explaining one embodiment of the method for detecting the remaining amount of the developer according to the present invention. FIG.
The method for detecting the remaining amount of the developer according to the present invention will be described with reference to FIG.

In the present invention, the developer amount detection value V32 detected by the developer remaining amount detection circuit 100 and the detection level reference voltage V3 detected by the detection level reference voltage circuit 120a are used.
3, the remaining amount of the developer is corrected and calculated by the developer remaining amount detection control circuit 102a. In other words, the CPU of the control circuit 102a is provided with a control formula for calculating the remaining amount of the developer according to the detected detection value V32 and the detection level reference voltage V33. The calculation of the remaining amount of the developer is started at the timing when the detection voltage V32 is output.

More specifically, the detection level reference voltage circuit 120a detects the reference voltage V31 at the same time that the control circuit 102a detects the developer remaining amount detection value V32, and calculates the temperature and humidity from the reference voltage V31. Then, the detection level reference voltage V33 is calculated based on the calculated value.

The control circuit 102a calculates the developer remaining amount based on the detected developer remaining amount detection value V32 and the detection level reference voltage V33 from the detection level reference voltage circuit 120a.

At the time when this series of detection of the remaining amount of the developer is completed, the remaining amount of the developer present in the cartridge is calculated.

By performing such processing, it is possible to stably detect the remaining amount of the developer irrespective of the change in the capacitance of the electrode and the change in the dielectric constant of the developer due to the influence of temperature and humidity.

In this embodiment, the impedance element, that is, the reference electrode means 20B1 is provided inside the cartridge. However, even when the impedance element is provided outside the cartridge, the same processing can be performed to detect the remaining amount of the developer. It is possible.

On the other hand, according to the present embodiment, the developer presence / absence detecting means 110A comprises the measuring electrode means 20A2 and the reference electrode means 20B2, which are electrodes formed of antenna rods installed in the cartridge.
Both are provided at a predetermined distance from the developing roller 9a along the longitudinal axis of the developing roller 9a. The measurement antenna electrode 20A2 is arranged at a position where it contacts the developer, and the reference antenna electrode 20B2 is arranged at a position where it does not contact the developer.

A measurement electrode means 20A2 as a detecting member having a capacitance Ca2 which varies in accordance with the amount of developer between the developing roller 9a and a comparison having a predetermined capacitance Cb2 between the developing roller 9a. The reference electrode means 20B2 as a member is connected to the control circuit 102b of the developer presence / absence detection circuit 100, respectively.

The detection level reference voltage circuit 120b of the developer presence / absence detection circuit 110 is supplied with the reference voltage V31 of the developer remaining amount detection circuit 100.
The output of 20b is input to the developer presence / absence detection control circuit 102b. The detection level reference voltage circuit 120b can also serve as the detection level reference voltage circuit 120a.

The reference electrode means 20B2 uses the AC (alternating current) I41 to set a reference voltage V41 for detecting the presence or absence of the developer. That is, the developer presence / absence detection circuit 110
As shown in FIG. 20, the reference electrode means 20B2, that is, the AC current I41 applied to the impedance element and the voltage drop V1 generated by the resistor R10 are converted into the resistors R11 and R11.
The reference voltage V41 is determined by adding the value to V2 set in step S12.

As described above, the measurement antenna electrodes 20A2 are arranged at predetermined intervals on the developing roller 9a so as to face each other, and are connected to the control circuit 102b as the developer capacity Ca2. Therefore, A is applied to the developer capacity Ca2 between the developing roller 9a and the measurement antenna electrode 20A2.
The C (alternating) current I42 is applied to the amplifier circuit 103b, and the detection value V42 (= V41−I42 × R)
4) is output.

With the above-described structure provided with the reference electrode means 20B2, the measurement electrode means 20A changed in temperature and humidity characteristics.
The capacitance (ΔC) that is the same as the capacitance value ΔCa of the second electrode 2 also changes in the reference electrode unit 20B2, and as a result, the measurement value of the measurement electrode unit 20A2 is corrected.

In this embodiment, the reference electrode means, ie,
As described above, the reference antenna electrode 20B2 functions as an element for detecting the temperature and humidity inside the cartridge, and the reference electrode means 20B1 functions as an element for correcting a change in the dielectric constant due to the dielectric constant of the developer. Therefore, in this embodiment, the detection level reference voltage V43 is output by the detection level reference voltage circuit 120b according to the change of the reference voltage V31 which is the output voltage from the reference antenna electrode 20B1, and the measured value is corrected. As a result, it is possible to detect the presence or absence of the developer without the influence of the dielectric constant of the developer which varies depending on the temperature and the humidity.

FIG. 21 is a flowchart for explaining an embodiment of the developer remaining amount detecting method according to the present invention. FIG.
The method for detecting the remaining amount of the developer according to the present invention will be described with reference to FIG.

According to the present invention, the developer presence / absence detection value V42 detected by the developer presence / absence detection circuit 110 and the detection level reference voltage V2 detected by the detection level reference voltage circuit 120b are used.
43, the developer presence / absence detection control circuit 102b corrects and calculates the presence / absence of the developer. That is, the CPU of the control circuit 102b is provided with a control formula for calculating the presence or absence of the developer in accordance with the detected detection value V42 and the detection level reference voltage V43. The calculation of the presence or absence of the developer is started at the timing when the detection voltage V42 is output.

More specifically, at the same time that the control circuit 102b detects the developer presence / absence detection value V42, the detection level reference voltage circuit 120b detects the reference voltage V31, and calculates the temperature and humidity from the reference voltage V31. , The detection level reference voltage V43 is calculated based on the calculated value.

The control circuit 102b calculates the presence / absence of the developer based on the detected developer presence / absence detection value V42 and the detection level reference voltage V43 from the detection level reference voltage circuit 120b.

When this series of detection of the presence or absence of the developer is completed, the presence or absence of the developer present in the cartridge is calculated.

By performing such processing, stable detection of the presence or absence of the developer can be performed without being affected by the change in the capacitance of the electrode and the change in the dielectric constant of the developer due to the influence of temperature and humidity.

In this embodiment, the impedance element, that is, the reference electrode means 20B2 is provided inside the cartridge. However, even when the impedance element is provided outside the cartridge, the same processing can be performed to detect the remaining amount of the developer. It is possible.

In the present embodiment, the output from the developing bias circuit is used as the driving bias of the developer remaining amount detecting means. However, the present invention is not limited to this, and any bias power supply can be used.

According to the image forming apparatus of the present invention, as described above, the amount of developer in the developer container 9A is sequentially detected, and the consumption of the developer is displayed based on the information. Accordingly, it is possible to prompt the user to prepare the developer replenishment cartridge, and further to prompt the user to replenish the developer based on the developer end detection information.

The developer amount display method will be described. For example, information detected by the above-described developer amount detection device is displayed on a terminal screen of a user's personal computer or the like in FIGS.
Is displayed as shown. 13 and 14, the user is notified of the amount of developer based on which part of the gauge 42 the needle 41 that moves according to the amount of developer is pointing.

As shown in FIG. 15, a display unit such as an LED may be provided directly on the main body of the electrophotographic image forming apparatus, and the LED 43 may be turned on and off according to the amount of the developer.

In the present invention, when the amount of the developer contained in the container is initially set to 100%, the amount of the developer is sequentially detected over the entire region from 100% to 0%. However, the present invention is not limited to this. For example, the developer may be sequentially detected over a region where the remaining amount of the developer in the container is 50% to 0%. Here, the remaining amount of the developer is 0%
Does not 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.

[0156]

As described above, the electrophotographic image forming apparatus of the present invention comprises (A) an electrode pair for sequentially detecting the remaining amount of the developer by contacting the developer in the developer container. Measuring electrode means having first and second electrodes, reference electrode means arranged at a position not in contact with the developer and forming first and second electrodes forming an electrode pair; Bias applying means for applying an AC bias voltage to the first electrode and the first electrode of the reference electrode means; first and second electrodes of the measuring electrode means generated by applying an AC bias voltage to the measuring electrode means And an electric signal corresponding to the capacitance between the first electrode and the second electrode of the reference electrode means generated by applying an AC bias voltage to the reference electrode means. The electrical signal corresponding to the Developer remaining amount detection control means for calculating the remaining amount of the image agent; and the remaining amount of the developer based on an electric signal corresponding to the capacitance between the first electrode and the second electrode of the reference electrode means Or (B) a developing device in a developer container disposed at a predetermined distance from the developer carrier. Measuring electrode means for detecting the presence or absence of the developer in contact with the developer; disposed at a predetermined distance from the developer carrier;
Reference electrode means disposed at a position not in contact with the developer;
Bias applying means for applying an AC bias voltage to the developer carrier; electricity generated by applying an AC bias voltage to the developer carrier and corresponding to the capacitance between the developer carrier and the measuring electrode means Signal in the developer container based on a static signal and an electrical signal generated by applying an AC bias voltage to the developer carrier and corresponding to a capacitance between the developer carrier and the reference electrode means. A developer presence / absence detection control means for calculating the presence / absence of the developer; and a developer obtained by the developer presence / absence detection control means based on an electric signal corresponding to a capacitance between the developer carrier and the reference electrode means. A correction means for correcting the presence / absence detection value, or further comprising the above (A) and (B). (1) Developer due to fluctuations in temperature, humidity, and dielectric constant of developer Variation in detection result of remaining amount or developer presence / absence It is possible to display the remaining amount of the developer or the presence / absence of the developer with high accuracy, which is more preferable for the user, by suppressing the crack. (2) The detection result of the remaining amount of the developer or the presence or absence of the developer based on the temperature, the humidity, and the dielectric constant of the developer is corrected without providing a special temperature, humidity, and the dielectric constant of the developer, thereby increasing the cost. Without this, it is possible to detect the remaining amount of the developer or the presence / absence of the developer with high accuracy in real time. (3) The developer can be used without waste without causing any adverse effects on the image and without bothering the user. (4) The amount of developer having a simple structure capable of more accurately and accurately detecting a state from a full state of the developer to a near-end state immediately before a printing failure even in a developing device or a process cartridge having a long life. A detection device is provided, which can further improve the convenience of the user when using the device, and is inexpensive. (5) It is possible to accurately monitor the consumption state of the developer even when a plurality of people use the printer or perform a large-scale print job, and to accurately grasp the timing of replacing the developing device or the process cartridge. Is provided, and the convenience in using the device by the user can be further improved, and the cost is low. This has the effect.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a control system of the electrophotographic image forming apparatus according to the present invention.

FIG. 3 is a diagram showing a schematic configuration of an embodiment of a developer amount detecting device according to the present invention.

FIG. 4 is a specific circuit diagram of an embodiment of a developer remaining amount detection circuit of FIG. 3;

FIG. 5 is a flowchart illustrating a developer remaining amount detection method according to the present invention.

FIG. 6 is a perspective view of a developer container for describing a developer amount detecting device according to the present invention.

FIG. 7 is a front view showing an embodiment of the measuring electrode means and the reference electrode means.

FIG. 8 is a front view showing another embodiment of the measuring electrode means and the reference electrode means.

FIG. 9 is a perspective view of a developer container provided with a measurement electrode unit and a reference electrode unit, in which the reference electrode unit is installed in the developer container.

FIG. 10 shows a reference electrode means installed in a developer container;
FIG. 4 is a perspective view of a developer container provided with a measurement electrode unit and a reference electrode unit.

FIG. 11 is a graph for explaining a principle of detecting a developer amount according to the present invention.

FIG. 12 is a graph for explaining a principle of detecting a developer amount according to the present invention.

FIG. 13 is a diagram illustrating an example of a developer amount display.

FIG. 14 is a view showing another embodiment of a developer amount display.

FIG. 15 is a view showing another embodiment of the developer amount display.

FIG. 16 is a diagram showing a schematic configuration of another embodiment of the developer amount detecting device according to the present invention.

FIG. 17 is a specific circuit diagram of an embodiment of the developer presence / absence detection circuit of FIG. 16;

FIG. 18 is a flowchart illustrating a developer presence / absence detection method according to the present invention.

FIG. 19 is a diagram showing a schematic configuration of another embodiment of the developer amount detecting device according to the present invention.

20 is a specific circuit diagram of one embodiment of a developer remaining amount detection circuit and a developer presence / absence detection circuit of FIG. 16;

FIG. 21 is a flowchart illustrating a method for detecting the remaining amount of developer and the presence / absence of developer according to the present invention.

FIG. 22 is a schematic configuration diagram of an example of a conventional electrophotographic image forming apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 optical means 2 recording medium 4 transfer means 7 photosensitive drum (electrophotographic photosensitive member) 8 charging roller (charging means) 9 developing means (developing device) 9A developer container 9a developing roller (developer carrier) 9d developing blade ( (Developer amount regulating member) 10 cleaning means 20A, 20A1, 20A2 measuring electrode means 20B, 20B1, 20B2 reference electrode means 23 first electrode 24 second electrode 40 cartridge mounting means 100A developer remaining amount detecting means 100 developer remaining Amount detection circuit 101 Developing bias applying means (developing bias circuit) 102a, 102b Control circuit 103 Amplifying circuit 110A Developer presence / absence detection means 110 Developer presence / absence detection circuit 120a, 120b Correction means (detection level reference voltage circuit)

Continued on the front page F-term (reference) 2H027 DA04 DA27 DA32 DD02 DD08 DE05 DE07 DE09 EA05 EC06 EC07 EC09 ED09 EF01 HB15 JC06 JC15 2H073 BA03 BA09 BA13 BA15 BA27 BA33 BA41 BA45 2H077 AA12 AA14 AD36 BA09 DA15 DA58 DA36 DA80 DA58 DA83 DA86 DB08 DB22 GA02 GA03

Claims (12)

[Claims] 1. 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 developer container provided with a developer carrier for containing and transporting the developer to the electrophotographic photosensitive member, and a developer remaining in the developer container being sequentially contacted with the developer in the developer container. (D) a first electrode and a second electrode which are arranged at a position not in contact with the developer and form a pair of electrodes. Reference electrode means having electrodes; (e) bias applying means for applying an AC bias voltage to a first electrode of the measuring electrode means and a first electrode of the reference electrode means; and (f) the measuring electrode means. The first of the measurement electrode means generated by applying an AC bias voltage to An electrical signal corresponding to the capacitance between the electrode and the second electrode, and a first electrode and a second electrode of the reference electrode means generated by applying an AC bias voltage to the reference electrode means. A developer remaining amount detection control means for calculating a remaining amount of the developer in the developer container based on an electric signal corresponding to a capacitance between the reference electrode means; Correction means for correcting the developer remaining amount detection value obtained by the developer remaining amount detection control means based on an electric signal corresponding to a capacitance between one electrode and a second electrode,
An electrophotographic image forming apparatus comprising: 2. 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 developer container provided with a developer carrier for containing and transporting the developer to the electrophotographic photosensitive member; and a developer container disposed at a predetermined distance from the developer carrier. (D) a developing device having a measuring electrode means for detecting the presence or absence of the developer in contact with the developer, and (d) being arranged at a predetermined distance from the developer carrier and not contacting the developer (E) bias applying means for applying an AC bias voltage to the developer carrying member;
(F) an electric signal generated by applying an AC bias voltage to the developer carrier and corresponding to a capacitance between the developer carrier and the measuring electrode means; Calculating the presence or absence of a developer in the developer container based on an electric signal generated by applying an AC bias voltage and corresponding to an electrostatic capacitance between the developer carrier and the reference electrode means. And (g) a developer obtained by the developer presence / absence detection control unit based on an electric signal corresponding to a capacitance between the developer carrier and the reference electrode unit. An electrophotographic image forming apparatus comprising: a correction unit configured to correct a presence / absence detection value. 3. 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 developer container provided with a developer carrier for containing and transporting the developer to the electrophotographic photosensitive member, and a developer remaining in the developer container being sequentially contacted with the developer in the developer container. A first measuring electrode unit having first and second electrodes forming an electrode pair for contacting a developer in a developer container arranged at a predetermined distance from the developer carrier; A second measuring electrode means for detecting the presence or absence of the developer, and (d) a first and a second electrode which are arranged at a position not in contact with the developer and form an electrode pair. The first reference electrode means, and a predetermined distance from the developer carrier, so as to be in contact with the developer. (E) the first electrode of the first measuring electrode means, the first electrode of the first reference electrode means, and the developer carrying member. Bias application means for applying an AC bias voltage; and (f) a first electrode and a second electrode of the first measurement electrode means generated by applying an AC bias voltage to the first measurement electrode means. And an electric signal corresponding to a capacitance between the first reference electrode means and the first reference electrode means.
A remaining amount of the developer in the developer container based on an electric signal corresponding to a capacitance between the first electrode and the second electrode of the reference electrode means. Detection control means;
(G) an electric signal corresponding to a capacitance between the developer carrier and the second measuring electrode means, which is generated by applying an AC bias voltage to the developer carrier, and the developer An electric signal corresponding to a capacitance between the developer carrier and the second reference electrode means, which is generated by applying an AC bias voltage to the carrier; (H) a developer presence / absence detection control means for calculating the presence / absence of the developer; and (h) based on an electric signal corresponding to a capacitance between the first electrode and the second electrode of the first reference electrode means. A first correction unit that corrects a developer remaining amount detection value obtained by the developer remaining amount detection control unit, and a first correction unit that corrects a capacitance between the developer carrier and the second reference electrode unit. Developer presence / absence obtained by the developer presence / absence detection control means based on the electrical signal And second correction means for correcting the detection value,
An electrophotographic image forming apparatus comprising: 4. An electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) (i) an electrophotographic photosensitive member; and (ii) the electrophotographic photosensitive member. A developer container containing a developer for developing the electrostatic latent image formed in the developer container, and a developer carrier for transporting the developer to the electrophotographic photosensitive member; and A developing device having a first electrode and a second electrode forming an electrode pair for sequentially detecting the remaining amount of the developer in contact with the developer of the developing device. (B) reference electrode means provided with first and second electrodes forming an electrode pair, which is disposed at a position not in contact with the developer;
(C) bias applying means for applying an AC bias voltage to the first electrode of the measuring electrode means and first electrode of the reference electrode means; and (d) applying an AC bias voltage to the measuring electrode means. An electric signal corresponding to a capacitance between a first electrode and a second electrode of the measurement electrode means to be generated; and the reference electrode means generated by applying an AC bias voltage to the reference electrode means. An electric signal corresponding to a capacitance between the first electrode and the second electrode, and a developer remaining amount detection control unit that calculates a remaining amount of the developer in the developer container based on the electric signal. (E) detecting the remaining amount of developer obtained by the remaining amount of developer detection control means based on an electric signal corresponding to a capacitance between a first electrode and a second electrode of the reference electrode means; Correction means for correcting the value. Image forming apparatus. 5. An electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) (i) an electrophotographic photosensitive member; and (ii) the electrophotographic photosensitive member. A developer container containing a developer for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and a developer container for transporting the developer to the electrophotographic photosensitive member; and A developing device having a measuring electrode means for detecting the presence or absence of the developer by contacting the developer in the developer container arranged at a predetermined distance from the developing device; Mounting means for mounting; (b) reference electrode means arranged at a predetermined distance from the developer carrier and not in contact with the developer; (c) the developer carrier To apply an AC bias voltage to (D) an electric signal corresponding to a capacitance between the developer carrying member and the measuring electrode means, which is generated by applying an AC bias voltage to the developer carrying member; Developing in the developer container based on an electric signal generated by applying an AC bias voltage to the developer carrier and corresponding to a capacitance between the developer carrier and the reference electrode means. Developer presence / absence detection control means for calculating the presence / absence of the developer; and (e) the developer presence / absence detection control means based on an electric signal corresponding to a capacitance between the developer carrier and the reference electrode means. And a correcting means for correcting the developer presence / absence detection value obtained in (1). 6. An electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) (i) an electrophotographic photosensitive member; and (ii) the electrophotographic photosensitive member. A developer container containing a developer for developing the electrostatic latent image formed in the developer container, and a developer carrier for transporting the developer to the electrophotographic photosensitive member; and A first measuring electrode unit having first and second electrodes forming an electrode pair for sequentially detecting the remaining amount of the developer in contact with the developer, and a predetermined distance from the developer carrier A process cartridge having a second measuring electrode means for detecting the presence or absence of the developer by contacting the developer in the developer container disposed at a distance; Mounting means for (b)
A first reference electrode means disposed at a position not in contact with the developer and having first and second electrodes forming an electrode pair, and disposed at a predetermined distance from the developer carrier; Second reference electrode means arranged at a position not in contact with
(C) bias applying means for applying an AC bias voltage to the first electrode of the first measuring electrode means, the first electrode of the first reference electrode means, and the developer carrier;
(D) an electric voltage corresponding to a capacitance between a first electrode and a second electrode of the first measuring electrode means generated by applying an AC bias voltage to the first measuring electrode means. A signal and an electrical voltage corresponding to a capacitance between a first electrode and a second electrode of the first reference electrode means generated by applying an AC bias voltage to the first reference electrode means. A developer remaining amount detection control means for calculating the remaining amount of the developer in the developer container based on the signal, and (e) applying the AC bias voltage to the developer carrying member. An electrical signal corresponding to a capacitance between the developer carrier and the second measuring electrode means; and an application of an AC bias voltage to the developer carrier, the developer carrier and the second And the reference electrode means. Developer presence / absence detection control means for calculating the presence / absence of developer in the developer container based on the target signal, and (f) the first electrode and the second electrode of the first reference electrode means. A first correction unit for correcting a developer remaining amount detection value obtained by the developer remaining amount detection control unit based on an electric signal corresponding to an electrostatic capacity between the developer carrier and the developer carrier; And a second correction unit for correcting a developer presence / absence detection value obtained by the developer presence / absence detection control unit based on an electric signal corresponding to a capacitance between the developer presence / absence detection control unit and the reference electrode unit. Electrophotographic image forming apparatus. 7. The method according to claim 1, wherein the first electrode and the second electrode of the measuring electrode means and the reference electrode means are formed in a comb-like or spiral manner. 4. The electrophotographic image forming apparatus of item 4. 8. The device according to claim 2, wherein the measurement electrode means and the reference electrode means are antenna electrodes arranged at a predetermined interval with respect to the developer carrier.
Electrophotographic image forming apparatus. 9. The first electrode and the second electrode of the first measurement electrode means and the first reference electrode means are formed in combination with each other in a comb shape or a spiral shape, and 7. An electrophotographic image forming apparatus according to claim 3, wherein said measuring electrode means and said second reference electrode means are antenna electrodes arranged at a predetermined interval with respect to said developer carrier. . 10. An electrophotographic image forming apparatus according to claim 3, wherein said first and second correction means generate a correction signal according to a change in a dielectric constant due to a temperature and a humidity of a developer. apparatus. 11. An electrophotographic image forming apparatus according to claim 3, wherein said first and second correction means are the same correction means. 12. The electrophotographic image forming apparatus according to claim 1, wherein said bias applying means is a developing bias applying means.