JP2001042607A - Electrophotographic image forming device, processing cartridge and electrifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic image forming device, a processing cartridge and an electrifying device, where shortening of a service life of the electrophotographic image forming device can be kept down to a minimum by decreasing scraped off amount of an electrophotographic sensitive body that is a body to be electrified, using a simple constitution, and failures in electrification due to contamination of the surface of an electrifying member is prevented. SOLUTION: This electrophotographic image forming device is provided with the electrophotographic sensitive body 3, the electrifying member 4 carrying out electrifying by being brought into contact with a surface of the electrophotographic sensitive body 3, an electrifying voltage impressing means 20 to have voltage impresss to the electrifying member 4, a voltage varying means 21 varying the voltage impressed by the electrifying voltage impressing means 20 to the electrifying member, a developer quantity detection means successively detecting the quantity of the developer inside a developer container and an environment detection means for detecting an environment in a vicinity of a developing means. The device is constituted so that the voltage impressed by the voltage impressing means 20 to the electrifying member 4 is varied by the voltage varying means, based on the detected results of the developer quantity detection means and the environment detection means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus for forming an image using an electrophotographic system, a process cartridge, and a charging device.

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

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, for example, an electrophotographic image forming apparatus such as a printer uniformly charges the surface of a cylindrical electrophotographic photosensitive member (photosensitive drum) as an image carrier, for example. A latent image is formed by selective exposure, and the latent image is visualized with a developer (including toner) to form a so-called toner image, and the toner image is transferred to a recording medium to perform image recording. .

In such an image forming apparatus, the developer must be supplied each time the developer runs out. However, this toner replenishment operation is not only troublesome, but also involves contamination. Further, maintenance of each member related to the electrophotographic image forming process can be performed only by a specialized service person, which often involves inconvenience for the user.

Therefore, in an electrophotographic image forming apparatus using an electrophotographic image forming process, the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrally made 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, the user can install the process cartridge in the apparatus main body, and when the developer runs out or the parts such as the photosensitive drum have reached the end of their life, they can be replaced. 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 is widely used in electrophotographic image forming apparatuses.

In recent years, in an electrophotographic image forming apparatus,
With the increase in the number of prints, the capacity of the process cartridge has been increased, that is, the life of the process cartridge has been extended with the increase in the capacity of the developer container integrally connected as the process cartridge. In such a process cartridge, it is desirable to have a means for sequentially informing the remaining amount of the process cartridge so that the user can easily predict the replacement time of the cartridge.

Therefore, in order to successively notify the remaining amount of the process cartridge, at least one pair of electrodes is used as a developer amount detecting means for sequentially detecting the remaining amount of the developer in the developer container of the process cartridge. A detection member having portions arranged at intervals is arranged at a position in contact with the developer in the developer container, and by measuring the capacitance between the electrodes of the detection member, the developing member in the developer container is measured. There is a method of detecting the remaining amount of the medicine.

According to this method, when the remaining amount of the developer in the developer container is large, the contact area between the detection member and the developer is large, so that the capacitance of the detection member is large, and as the remaining amount of the developer becomes small. The remaining amount of the developer is detected using the principle that the contact area between the developer and the detection member is reduced and the capacitance is also reduced.

[0010] However, in the above method, the capacitance may fluctuate due to environmental fluctuation (humidity fluctuation or the like) of the atmosphere around the detecting member. In other words, when the atmospheric humidity increases, the amount of moisture in the air increases and the dielectric constant increases,
Since the dielectric constant changes due to moisture absorption by the detection member itself, the capacitance value changes depending on the environment even with the same remaining amount of the developer.

In order to further improve the detection accuracy of the remaining amount of the developer, a means for detecting the amount of the developer with improved environmental fluctuation is arranged at a location in contact with the developer in the developer container, and A detection member having a portion in which a pair of electrodes are arranged at a predetermined interval, and a comparison member arranged in a location not in contact with the developer and having at least a pair of electrodes arranged in a predetermined interval, the capacitance of the detection member A method of detecting the remaining amount of the developer in the developer container by comparing the developer amount with the capacitance of the comparison member has been proposed.

In other words, a comparison member that performs the same environmental change as the detection member is arranged in the same environment as the detection member, and the two detection values are compared to obtain a difference, so that a change in capacitance due to the environment can be calculated. It cancels out and detects the remaining amount of developer with high accuracy.

On the other hand, as a method for charging the surface of, for example, a photosensitive drum as an image carrier as described above, conventionally,
Corona charging, which is non-contact charging, in which a corona generated by applying a high voltage to a thin corona discharge wire is applied to the surface of a photosensitive drum to perform charging, has been generally used.

In recent years, a charging member such as a roller type or a blade type has been brought into contact with the surface of a photosensitive drum as an object to be charged, in view of low voltage process, low ozone generation amount and low cost. Contact charging, in which a photosensitive member surface is charged by applying a voltage to a member, is becoming mainstream. In particular, a roller type charging member (hereinafter, referred to as a charging rotator)
It is called "charging roller". ) Can perform stable charging over a long period of time.

For example, in a roller type charging member, a conductive elastic roller is brought into pressure contact with a member to be charged, and a voltage is applied to the member to charge the member by discharging. Specifically, by applying a DC voltage obtained by adding a required photoreceptor surface potential Vd to a discharge start voltage to a charging roller, a DC charging method of charging a charged body, or an environment,
For the purpose of improving potential fluctuation due to durability fluctuation, etc.,
An AC having a peak-to-peak voltage that is twice or more the discharge starting voltage to a DC voltage corresponding to the required photoconductor surface potential Vd
There is an AC charging method in which a charged object is charged by applying a voltage on which a component is superimposed to a contact charging member. When charging is performed by pressing the charging roller against the OPC photosensitive member, the discharge starting voltage is typically about 550V.

However, in this contact charging system, a cleaning blade or the like is provided as a cleaning means provided for cleaning the surface of the photosensitive drum after the transfer, since the charging member is brought into contact with the photosensitive drum which is a member to be charged. Fine powder toner contained in the developer, external additives of the toner, etc. adhere and accumulate on the charging roller surface,
In some cases, image density unevenness due to poor charging or toner adhesion (fogging) to a white portion of an image may occur.

Regarding the surface contamination of the charging roller, D
The AC charging method is more advantageous than the C charging method. In particular, by increasing the peak-to-peak voltage of the AC component, it was possible to improve the level to a level at which there is no problem on the image.

[0018]

However, with the recent increase in the capacity of the process cartridge, the amount of deposits on the surface of the charging roller has increased, and a higher AC voltage has been required.

On the other hand, in the AC charging system, there is a problem that as the AC voltage is increased, the shaving amount of the photosensitive drum increases, and the life of the photosensitive drum is shortened.

Accordingly, it is an object of the present invention to reduce the amount of scraping of an electrophotographic photosensitive member as a member to be charged, to minimize the shortening of the life of the electrophotographic photosensitive member, and to minimize the surface of the charging member with a simple structure. An object of the present invention is to provide an electrophotographic image forming apparatus, a process cartridge, and a charging device that can prevent poor charging due to contamination of the image.

[0021]

The above object is achieved by an electrophotographic image forming apparatus, a process cartridge and a charging device according to the present invention. In summary, according to a first aspect of the present invention, in an electrophotographic image forming apparatus for forming an image on a recording medium, an electrophotographic photosensitive member, and a charging member which is charged by contacting the surface of the electrophotographic photosensitive member. Member, charging voltage applying means for applying a voltage to the charging member, voltage changing means for changing the voltage applied from the charging voltage applying means to the charging member, and a latent image forming a latent image on the electrophotographic photosensitive member. An image forming unit, a developing unit that visualizes a latent image formed on the electrophotographic photosensitive member with a developer, a developer container that stores the developer and supplies the developer to the developing unit, A developer amount detecting means for sequentially detecting an amount of the developer in the developer container; and an environment detecting means for detecting an environment near the developing means, wherein the voltage changing means detects the amount of the developer. Means and the environment detecting means The electrophotographic image forming apparatus from the voltage applying unit and changes the voltage applied to the charging member is provided on the basis of.

According to a second aspect of the present invention, in a process cartridge detachably mountable to an electrophotographic image forming apparatus main body, an electrophotographic photosensitive member; and at least the electrophotographic photosensitive member as a process means acting on the electrophotographic photosensitive member. A charging member that contacts and charges the surface of the photoconductor, and a developing unit that visualizes the electrostatic latent image formed on the electrophotographic photoconductor with a developer; A developer container for supplying an agent; and the charging member includes:
In a state where the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the process cartridge of the electrophotographic image forming apparatus main body based on an amount of a developer in the developer container and an environment in the vicinity of the developing unit. A process cartridge is provided in which a voltage changed according to a use situation is applied.

According to a third 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 detachable, wherein (a) an electrophotographic photosensitive member; A charging member that is charged by contacting at least the surface of the electrophotographic photosensitive member, and a developing device that visualizes an electrostatic latent image formed on the electrophotographic photosensitive member by a developer as a process unit that acts on the photographic photosensitive member. Mounting means for detachably mounting a process cartridge having means for storing a developer and supplying the developer to the developing means, and (b) the process cartridge is provided with the electrophotographic apparatus. Charging voltage applying means for applying a voltage to the charging member in a state of being mounted on the image forming apparatus main body; and (c) charging voltage applying from the charging voltage applying means to the charging member. And voltage changing means for changing,
(D) latent image forming means for forming an electrostatic latent image on the electrophotographic photoreceptor, wherein the process cartridge is mounted on the electrophotographic image forming apparatus main body;
The voltage changing unit changes the voltage applied from the charging voltage applying unit to the charging member in accordance with the use amount of the process cartridge based on the amount of the developer in the developer container and the environment near the developing unit. An electrophotographic image forming apparatus is provided.

According to a fourth aspect of the present invention, in a charging device for charging an electrophotographic photosensitive member, a charging member that contacts and charges the electrophotographic photosensitive member, and a charging voltage that applies a voltage to the charging member. Application means, and voltage changing means for changing a voltage applied from the charging voltage application means to the charging member, wherein the electrostatic latent image formed on the electrophotographic photosensitive member is visualized by a developer. The voltage applied from the charging voltage applying unit to the charging member is set based on the environment near the developing unit and the amount of the developer in the developer container that stores the developer and supplies the developing unit to the developing unit. There is provided a charging device characterized by a change.

In the first aspect of the present invention, according to one embodiment, the voltage applying means can apply DC and AC voltages to the charging member, and the voltage changing means can include the developer amount detecting means and the developer amount detecting means. The peak-to-peak voltage of the AC voltage is changed based on a detection result of the environment detecting means. or,
According to another embodiment, as the developer amount detection means and the environment detection means, a detection member provided with an electrode having a portion arranged at least a pair of juxtaposed at a predetermined interval, and disposed at a location in contact with the developer, A comparative member provided with an electrode having at least a pair of portions arranged side by side at a predetermined interval, and a capacitance of the detecting member as the developer amount detecting means. The amount of developer in the developer container is detected by detecting and comparing the capacitance of the comparison member, and the development is performed by detecting the capacitance of the comparison member as the environment detection unit. Detect the environment near the means. Further, according to another embodiment, a plurality of developing devices provided with the developing unit and the developer container, the developer amount detecting unit provided for at least a plurality of the plurality of developing devices, The voltage applied to the charging member is changed based on the detection result with the environment detecting means.

In the second and third aspects of the present invention,
According to one embodiment, a DC and AC voltage is applied to the charging member in a state where the process cartridge is mounted on the electrophotographic image forming apparatus, and the amount of the developer in the developer container and the amount of the developer are adjusted. The peak-to-peak voltage of the AC voltage is changed according to the use state of the process cartridge based on the environment near the developing unit.

In the second and third aspects of the present invention,
According to another embodiment, the process cartridge further includes a developer amount detecting unit for sequentially detecting a developer amount in the developer container, and an environment detecting unit for detecting an environment near the developing unit. In the charging member, in a state where the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the amount of the developer in the developer container and the vicinity of the developing unit in the main body of the electrophotographic image forming apparatus. A voltage changed according to the use condition of the process cartridge based on the environment is applied.

In the second and third aspects of the present invention,
According to another embodiment, the process cartridge further includes a developer amount detecting unit for sequentially detecting a developer amount in the developing container, and the charging member includes the process cartridge near the developing unit. When mounted on the main body of the electrophotographic image forming apparatus having environment detecting means for detecting an environment, the main body of the electrophotographic image forming apparatus uses the amount of developer in the developer container and the environment in the vicinity of the developing means. A voltage changed according to the use state of the process cartridge is applied.

In the second and third aspects of the present invention,
According to another embodiment, the process cartridge further includes environment detecting means for detecting an environment near the developing means, and the charging cartridge detects the amount of developer in the developer container by the process cartridge. When mounted on an electrophotographic image forming apparatus main body having a developer amount detecting means, the electrophotographic image forming apparatus main body includes a developer container based on a developer amount in the developer container and an environment near the developing means. A voltage changed according to the use state of the process cartridge is applied.

In the second and third aspects of the present invention,
According to another embodiment, the process cartridge comprises:
A detection member provided with an electrode having a portion arranged at least in a pair and arranged at a predetermined interval with a portion in contact with the developer; and a portion arranged at a location not in contact with the developer and arranged at least a pair of a predetermined interval A comparison member provided with an electrode having the following configuration: wherein the charging member has the process cartridge mounted on the electrophotographic image forming apparatus main body and the electrophotographic image forming apparatus main body has the detection member. The developer remaining amount in the developer container detected by detecting and comparing the capacitance of the member and the comparison member, and the developing amount detected by detecting the capacitance of the comparison member A voltage changed according to the use state of the process cartridge based on the environment near the agent means is applied.

In the second and third aspects of the present invention,
According to another embodiment, the process cartridge comprises:
A detecting member provided with an electrode having at least a pair of parts arranged side by side at a predetermined interval, wherein the detecting member is provided at a position where the process cartridge does not contact the developer; The detection member and the detection member are attached to the electrophotographic image forming apparatus main body while being mounted on the electrophotographic image forming apparatus main body having a comparison member provided with an electrode having portions arranged at least in pairs at predetermined intervals. The developer remaining amount in the developer container detected by detecting and comparing the capacitance of the comparison member, and the vicinity of the developer unit detected by detecting the capacitance of the comparison member A voltage changed according to the use condition of the process cartridge based on the environment is applied.

In the fourth aspect of the present invention, according to one embodiment, the voltage applying means is capable of applying DC and AC voltages to the charging member, and the electrostatic latent formed on the electrophotographic photosensitive member. Based on the environment in the vicinity of the developing means for visualizing the image with the developer and the amount of the developer in the developer container that contains the developer and supplies the developing means to the developing means, Change the peak-to-peak voltage. According to a preferred embodiment, the charging member is a rotator having an elastic layer in contact with the electrophotographic photosensitive member.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrophotographic image forming apparatus, a process cartridge, and a charging device 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 FIG. In the present embodiment, the image forming apparatus is an electrophotographic laser beam printer,
Recording medium by the electrophotographic image forming process, for example,
An image is formed on a recording paper, an OHP sheet, a cloth, or the like.

The image forming apparatus of this embodiment has a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum 3 as an image carrier. In the present embodiment, as the photosensitive drum 3, O
A PC photoreceptor was used. An electrostatic latent image is formed on the surface of the photosensitive drum 3 by a latent image forming unit. That is, the surface of the photoconductor drum 3 applies a voltage to a charging roller 4, which is a roller-shaped charging rotator, as a charging member that comes into contact with the surface of the photoconductor drum 3 by charging voltage application means (not shown). Charge. Next, a scanner unit 1 serving as an exposure unit having a laser light source, a polygon mirror, and a lens system scans and outputs a laser beam modulated in accordance with an image signal. Irradiation on the drum 3 forms an electrostatic latent image on the photosensitive drum according to image information. The latent image is developed by the developing means 7 using a developer (including toner).
To form a visible image, that is, a toner image.

That is, the developing means 7 is provided with the developing roller 5 as a developer carrying member, and the developer in the developer container 8 as a developer accommodating portion formed adjacent to the developing means 7 is used. The developer is fed to the developing roller 5 by the rotation of the developer feeding member 10. As the developing roller 5 rotates, the developer is conveyed on the developing roller 5, and a triboelectric charge is applied by rubbing with the developing blade 6 as a developer layer thickness regulating means, and the developer is transferred to the developer layer having a predetermined thickness. Then, the developer is supplied to a developing area, which is an opposing portion between the photosensitive drum 3 and the developing roller 5. The developer supplied to the developing area is transferred to a latent image on the photosensitive drum 3 to form a toner image. The developing roller 5 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, the recording medium P stored in the paper feed cassette 11 is supplied to the registration roller pair 13 by the paper feed roller 12 in synchronization with the formation of the latent image on the photosensitive drum 3. Then, the recording medium P is conveyed to the transfer position in synchronization with the leading end of the toner image formed on the photosensitive drum 3 by the registration roller pair 12. At the transfer position, a roller-shaped charger (transfer roller) as transfer means
The toner image on the photosensitive drum 3 is transferred to the recording medium P by applying a voltage to the transfer roller 14.

Next, the recording medium P on which the toner image has been transferred
Is transported to the fixing device 15, and the toner image on the recording medium P is permanently fixed to the recording medium P by the fixing device 15 by heat and pressure. Thereafter, the recording medium P is discharged outside the image forming apparatus.

The developer (toner, external additive, etc.) remaining on the photosensitive drum 3 after the transfer of the toner image onto the recording medium P by the transfer roller 14 is replaced with an elastic blade (cleaning blade) as a cleaning means. The photosensitive drum 3 is removed by the developer 16 and collected in a waste developer reservoir 17, and is repeatedly used for image formation.

According to this embodiment, the photosensitive drum 3, the charging roller 4, the developing means 7, the cleaning means 16, which are process means acting on the photosensitive drum 3, and the developer container which is a developer accommodating portion The process cartridge C and the waste developer reservoir 17 are collectively unitized by the frames 9 and 18 and the like.

These components are assembled in the process cartridge C with a predetermined mutual arrangement relationship. The process cartridge C is inserted into a predetermined portion in the main body of the image forming apparatus in a predetermined manner. The image forming apparatus is mounted on the image forming apparatus main body via mounting means 19 formed on the image forming apparatus main body. Conversely, it can be pulled out of the image forming apparatus main body.

When the image forming apparatus has been used for a long time, various elements such as the photosensitive drum 3, the charging roller 4, the developing means 7, and the cleaning means 16 are worn out and deteriorate the image quality. In this case, the user only needs to replace the process cartridge C, and maintenance-free operation can be realized.

Next, the charging device used in this embodiment will be described. FIG. 2 schematically shows a charging device constructed according to the present invention and the vicinity thereof.

The charging device 40 used in this embodiment is
As a charging member, a charging roller 4 which is a roller-shaped charging rotator is provided. As shown in FIG. 2, according to the present embodiment, the charging roller 4 includes a metal core 4a, an elastic layer 4c, and a surface layer 4c, both ends in the longitudinal direction are supported by bearings (not shown), and a pressure spring is provided. , And comes into pressure contact with the photosensitive drum 3, and rotates in accordance with the rotation of the photosensitive drum 3 in a direction indicated by an arrow in FIG.

A high voltage power supply 20 as charging voltage applying means is connected to the metal core 4a of the charging roller 4, and a control unit (not shown) which is a control circuit for controlling the operation of the image forming apparatus in a general manner. A voltage is applied to the charging roller 4 from the high voltage power supply 20 via the metal core 4a under the control of a central processing unit (CPU) 21 as a control means provided in the charging roller 4).

In this embodiment, a voltage obtained by superimposing a DC voltage corresponding to a desired charging potential Vd of the photosensitive drum 3 with an AC component having a peak-to-peak voltage that is twice or more the discharge starting voltage is applied to the charging roller 4. A so-called AC charging method, in which the surface of the photosensitive drum 3 is charged by applying the voltage, is used.

As will be described in detail later, the CPU 21 controls the voltage applied to the charging roller 4 in accordance with the use condition of the process cartridge (remaining amount of developer and environmental humidity).
That is, in the present embodiment, the CPU 21 that controls the operation of the image forming apparatus has the function of the voltage changing unit.

Here, the inventor of the present invention has conducted intensive studies through various experimental studies on how the charging roller 4 is contaminated through the life endurance of the process cartridge C, and as a result, 1) the adhering material on the charging roller 4 It is mainly a fine powder toner smaller than a normal particle size, and silica particles externally added to the toner. 2) Under a low humidity environment, the fine powder toner is often attached particularly in the latter half of use of the process cartridge C.
3) Under a high humidity environment, it was found that the adhesion of the external additive was remarkable especially in the early stage of using the cartridge.

Based on the above examination results, the present inventor grasps the use condition of the process cartridge C, and changes the AC voltage applied to the charging roller 4 according to the use condition of the process cartridge C, so that the present invention is effective. It has been found that it is possible to prevent the occurrence of a defective image due to charging failure due to surface contamination of the charging roller 4.

That is, the parameters required as the usage status of the cartridge here are the usage amount of the process cartridge C, that is, the remaining amount of the developer in the developer storage unit 8 and the environmental humidity of the atmosphere.

The use condition detecting means used to grasp the use condition of the process cartridge C is not particularly limited, and a known developer amount for sequentially detecting the developer amount in the developer container 8 is used. A known environmental sensor (such as a humidity sensor) for detecting the environment (humidity) in the vicinity of the detecting means and the developing means 7 can be used.

On the other hand, in this embodiment, the remaining amount of the developer in the developer container 8 is sequentially detected with higher accuracy, and the environment (humidity) near the developing means 7 can be detected without providing a dedicated sensor. ) Can be detected. This will be described in detail below.

First, according to the present embodiment, the image forming apparatus
There is provided a developer amount detecting means capable of sequentially detecting the remaining amount of the developer in the developer container 8 according to consumption of the developer.

FIG. 3 shows the schematic structure of the developer container 8 in more detail. The developer amount detecting means of the present embodiment includes an input-side electrode 33 having at least a pair of parts arranged at a predetermined interval, which are arranged at a position in contact with the developer in the developer container 8 of the process cartridge C; A measurement electrode member 30A, which is a detection member having an output side electrode 34, and an input side electrode 33 having at least a pair of portions arranged at a predetermined interval in the vicinity of the developing means 7 and not in contact with the developer; A reference electrode member 30 </ b> B, which is a comparison member including the output-side electrode 34.

That is, in the present embodiment, the capacitance varies in accordance with the contact area with the developer, and the measuring electrode member (detecting member) 30A for detecting the amount of the developer and the environment, that is, the temperature of the atmosphere, The capacitance fluctuates due to environmental conditions such as humidity,
A reference electrode member (comparison member) 30B as a comparison member that outputs a reference signal.

As shown in FIG. 3, for example, as shown in FIG. 3, the measuring electrode member 30A is located at a position in contact with the developer, such as the inner side surface of the developer container 8, and as the developer decreases, the developer electrode 30A Are arranged in such a direction that the contact area varies. Further, the reference electrode member 30B can be installed at an arbitrary position of the image forming apparatus main body which does not come into contact with the developer and is in the vicinity of the developing means 7, but the details will be described later. As shown in FIG. 7, a partition wall 31 inside the developer container 8 of the process cartridge C or inside the developer container 8 as shown in FIG.
May be provided at a location which is not contacted with the developer. Further, as shown in FIG. 8B, for example, the measurement electrode member 30A and the reference electrode member 30B are integrally formed in a symmetrical arrangement, and the partition wall 31 is formed in the developer container 8 on the same side. May be provided at a location which is not contacted with the developer.

As shown in FIG. 4, the measuring electrode member 30A is a pair of electrodes having portions juxtaposed at a predetermined interval in the same plane on the substrate 32, that is, the input-side electrode 3A.
3 and an output-side electrode 33. In this embodiment, the electrode 3
3 and 34 have at least a pair of electrode portions 33a to 33f and 34a to 34f arranged in parallel at a predetermined interval G, and each of the electrode portions 33a to 33f and 34a to 34f is connected to the connection electrode portions 33g and 34g. Are connected to each other,
The two electrodes 33 and 34 have a large number of uneven shapes combined with each other. Of course, the electrode pattern of the measurement electrode member 30A is not limited to this. For example, a pair of electrodes 33 and 34 may be formed in a spiral shape arranged in parallel at a predetermined interval.

The measuring electrode member 30A includes a pair of parallel electrodes 3
The remaining amount of the developer in the developer container 8 can be successively detected by measuring the capacitance between the third and the 34th. That is, a voltage is applied between the input-side electrode member 33 and the output-side electrode 34 from a voltage application unit (not shown) provided in the image forming apparatus main body, and a control circuit (not shown) provided in the image forming apparatus main body. ), The capacitance between the electrodes 33 and 34 is detected, and since the developer has a higher dielectric constant than air, the developer comes into contact with the surface of the measurement electrode member 30A.
The capacitance between the pair of electrodes 33 and 34 of the measurement electrode member 30A increases in proportion to the contact area with the developer.

Therefore, by using the measuring electrode member 30A having the above structure, a predetermined calibration curve is applied from the area of the developer in contact with the surface of the measuring electrode member 30A. The amount of developer in the developer container 8 can be measured regardless of the shape of the member 30A.

The electrode patterns 33 and 34 of the measuring electrode member 30A can be formed in the manner of forming a wiring pattern on a printed circuit board. That is, by forming conductive metal patterns 33 and 34 such as copper by etching or printing on a hard printed board 32 such as paper phenol or glass epoxy, or a flexible printed board 32 such as polyester or polyimide. It can be manufactured in the same manner as the usual method for forming a wiring pattern on a printed circuit board.

Further, by using a complicated pattern shape as shown in FIG. 4, the facing length between the electrodes 33 and 34 can be lengthened, and further by using a pattern forming method such as etching. The interval G can be reduced to about several tens of μm, and a large capacitance can be obtained. Further, the amount of change in the capacitance can be increased, and the detection accuracy can be increased. Further, the metal pattern forming surface can be laminated with, for example, a thin resin film.

On the other hand, according to the present invention, as shown in FIG. 3, the developer amount detecting means further has a reference electrode member 30B having the same configuration as the measuring electrode member 30A. As described above, the capacitance of the reference electrode member 30B varies depending on environmental conditions such as temperature and humidity, and
It functions as a reference comparison member for 0A.

That is, when the humidity of the atmosphere around the measuring electrode member 30A becomes high, the amount of moisture in the air increases and the dielectric constant increases, or the dielectric constant changes due to the reference electrode member 30A itself absorbing moisture. Therefore, even if the remaining amount of the developer is the same, the value of the capacitance varies depending on the atmospheric humidity.

Therefore, the reference electrode member 30B as a comparison member which has the same environmental change as the measurement electrode member 30A has the same configuration as the measurement electrode member 30A, for example.
It is arranged in the same environment (humidity) as 0A and at a place where it does not come into contact with the developer. Then, similarly to the measurement electrode member 30A, a voltage applying unit (not shown) provided in the image forming apparatus main body.
Control means (not shown) which is a control circuit provided in the main body of the image forming apparatus by applying a voltage between the electrodes 33 and 34 from
The capacitance of the reference electrode member 30B is measured, and the capacitance of the measurement electrode member 30A and the capacitance of the reference electrode member 30B are measured and compared. The offset can be offset, and highly accurate detection of the remaining amount of the developer can be realized without being affected by environmental fluctuations.

Referring to FIG. 5 and FIG. 6, as shown in the leftmost bar graph of FIG. 5, the electrostatic capacitance measured from the measuring electrode member 30A which is the detecting member for detecting the amount of the developer. The capacity is output by adding the environmental variation to the variation due to the developer in contact with the surface of the detection member 30A. Then, when it is moved to a high temperature and high humidity environment,
As shown in the leftmost bar graph, the variation due to the developer does not change, but the environmental variation increases. As a result, the capacitance increases despite the same amount of developer. Therefore, a reference electrode member (comparison member) 30B having the same environmental fluctuation as the measurement electrode member (detection member) 30A as shown in the center bar graphs of FIGS. Accordingly, only the capacitance due to the developer can be measured.

As described above, according to the developer amount detecting means of the present invention, the reference electrode member 30B whose capacitance varies depending on the environment is installed as the comparison member, similarly to the measurement electrode member 30A. Fluctuations due to the environment of the electrode member 30A can be canceled, and the remaining amount of the developer can be detected with high accuracy.

Further, as described above, the reference electrode member 30B as a comparison member can be installed in an arbitrary configuration in the vicinity of the developing means 7 and at an arbitrary position not in contact with the developer.

For example, as shown in FIGS. 3 and 9A, a reference electrode member 30B having the same configuration as the measurement electrode member 30A can be disposed as a comparison member in the image forming apparatus main body. As shown in FIGS. 7, 8A, 9B, and 9B, the developer container 8 has the same configuration as the measurement electrode member 30A, and the comparison member has the same configuration as the measurement electrode member 30B. And the reference electrode member 30B. In the present embodiment, as shown in FIG. 7, the measurement electrode member 30A is disposed on the inner side surface of the developer container 8, and the comparison member 30B is outside the developer container 8, and is provided with the measurement electrode member 30A. The developer container 8 is disposed on the outer surface of the frame 9 forming the developer container 8.

The reference electrode member 30B can have the same configuration as the above-mentioned measurement electrode member 30A, but it is not necessarily required to be the same, and the width, length, interval, area, material, It is also possible to make the configuration different. In this case, a coefficient based on the correlation of the humidity characteristics may be applied.

As described above, according to the present embodiment, the capacitance calculated from the capacitance of the measurement electrode member 30A and the capacitance of the reference electrode member 30B is equal to the capacitance on the surface of the measurement electrode member 30A. It is proportional to the area in contact with the developer, and by performing conversion based on an appropriate correlation curve, the remaining amount of the developer can be sequentially calculated. By applying the correlation curve, any shape can be used for the sectional shape of the developer container 8 and the shape of the measurement electrode member 30A and the reference electrode member 30B. Also, the shapes of the electrode patterns 33 and 34,
There is no particular limitation on the preparation method and the like.

The 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. In FIGS. 10 and 11, the user is notified of the amount of developer based on which part of the gauge 52 the needle 51 that moves according to the amount of developer is pointing. In addition, as shown in FIG. 12, a display unit such as an LED may be provided directly on the main body of the electrophotographic image forming apparatus, and the LED 53 may blink according to the amount of the developer.

The remaining amount of the developer can be sequentially detected over the entire region from 100% to 0% corresponding to the initial filling amount of the developer in the developer container 11A. Although the amount can be sequentially displayed in the entire region from 100% to 0%, the present invention is not limited to this. For example, the remaining amount of the developer in the region of 50% to 0% is sequentially displayed. The display may be configured to be displayed. Furthermore, the fact that the remaining amount of the developer is 0% does not only mean that the developer has completely disappeared. For example, even if the developer remains, a predetermined image quality (development quality)
This also includes the fact that the remaining amount of the developer has decreased to such an extent that no toner can be obtained.

Further, according to the present invention, the output of the reference electrode member (comparative member) 30B, that is, the capacitance of the comparative member 30B that fluctuates depending on the environment is measured independently, that is, FIGS. By measuring the capacitance itself corresponding to the environmental change shown by the central bar graph in (3), the environment (humidity) of the atmosphere around the reference electrode member 30B can be detected. As described above, according to the present embodiment, the reference electrode member 30B also functions as an environment detecting unit for grasping the use status of the process cartridge C.

That is, when the humidity of the atmosphere around the comparison member 30B increases, the amount of moisture in the air increases and the dielectric constant increases, or the dielectric constant increases because the reference electrode member 30B itself absorbs moisture. Therefore, a voltage is applied between the electrodes 33 and 34 of the reference electrode member 30B from a voltage applying means (not shown) provided in the image forming apparatus main body, and a control means (not shown) is a control circuit provided in the image forming apparatus main body. In (d), the environment (humidity) in which the reference electrode member 30B is placed can be detected by detecting the capacitance of the reference electrode member 30B and applying a predetermined correlation curve.

As described above, according to this embodiment, the measuring electrode member 30A and the reference electrode member 3 provided in the developer amount detecting device are provided.
OB can be used to detect both the remaining amount of the developer in the developer container 8 and the environment (humidity) in the vicinity of the developing means 7.

As described above, a parameter necessary as a usage state of the process cartridge C to be grasped for controlling the voltage applied to the charging roller 4 is a usage amount of the process cartridge C, that is, a parameter in the developer container 8. And the environmental humidity of the atmosphere. In the present embodiment, the developer amount in the developer container 8 can be extremely accurately determined by using the developer amount detecting means including the detection member (measurement electrode member) 30A and the comparison member (reference electrode member) 30B. Since the detection member 30B and the comparison member 30B can function as environment detection means, it can also detect the environment in the vicinity of the development means 7 and a dedicated environment sensor for detecting the environment (humidity) around the development means 7. There is no need to provide such a device.

Next, control of the voltage applied to the charging roller 4 based on the use state of the process cartridge C will be described.

FIG. 13 shows the life of the image forming apparatus of this embodiment in which the developer was initially charged with 1000 g and the life was 200 g.
This shows how the charging roller 4 is stained when a durability test is performed up to the service life using 00 process cartridges C.
FIG. 13 shows a typical example of how the charging roller 4 becomes dirty in a high humidity environment and a low humidity environment.

In FIG. 13, the horizontal axis indicates the remaining amount of the developer in the developer container 8 of the process cartridge C, and the vertical axis indicates the amount of dirt on the charging roller 4. Also, the hatched area in the figure is
The range of the amount of dirt in which charging failure occurs due to surface contamination of the charging roller 4 when the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 is low.

FIG. 13 shows that in a low humidity environment, the surface contamination of the charging roller 4 becomes remarkable especially in the latter half of the use of the process cartridge C, and in a high humidity environment, especially in the early stage of the use of the cartridge. It can be seen that the surface contamination tends to be remarkable.

From the results shown in FIG. 13 and the results of many experimental studies by the present inventor, in the image forming apparatus of this embodiment, the detecting member (measuring electrode member) 30 as the developer amount detecting means is used.
A, based on the detection result of the comparison member (reference electrode member) 30B, the usage status of the process cartridge
% Or more and the remaining amount of developer is 75% or more, or when it is determined that the humidity is 40% or less and the remaining amount of developer is 25% or less, the charging bias voltage applied to the charging roller 4 The peak-to-peak voltage Vpp of the AC component
As (V), when it is determined that the usage state is other than that, the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 is controlled to 1800 (V).

The general procedure for controlling the voltage applied to the charging roller 4 will be described. First, at the start of the image forming operation, the AC of the charging bias voltage applied to the charging roller 4 is set.
The peak-to-peak voltage Vpp of the component is set to 2200 (V), and the use status of the process cartridge C is immediately detected. Based on this detection result, the charging bias voltage AC
It is determined whether to change the peak-to-peak voltage Vpp of the component to 1800 (V), and if necessary, image formation is started.

Control means for detecting the capacitance of both members based on the outputs from the measurement electrode member (detection member) 30A and the reference electrode member (comparison member) 30B, and detecting the amount of developer based on the capacitance. The control means for detecting the capacitance of the reference electrode member 30B based on the output of the reference electrode member 30B and detecting the environment (humidity) in the vicinity of the developing means 7 is based on the detected amount of the developer and the environment. The CPU 2 of a control unit (control circuit) that controls the operation of the image forming apparatus by judging the usage status of the process cartridge C and also serving as a voltage changing unit that controls the charging voltage applied to the charging roller 4.
1 may include the function, for example,
A configuration may be adopted in which individual control means are used, and the voltage changing means changes the charging voltage applied to the charging roller 4 based on a signal from each control means.

When the above-described control was performed and an image forming test of 20,000 sheets was actually performed in a high-temperature, high-humidity, and low-temperature, low-humidity environment, the charging roller 4 was contaminated to cause poor charging. No image defects such as density unevenness and toner adhesion (fogging) to the white portion occurred, and no image defects due to scraping of the photosensitive drum 3 occurred.

Further, the life of the photosensitive drum 3 was examined. The variation of the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 under the control of the present embodiment is 22,000 which exceeds the target life of 20,000 sheets of the process cartridge C used in the present embodiment. Sheet image formation was achieved.

On the other hand, for comparison, the charging roller 4
In the case where the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to
At the time when the 00 sheet image was formed, an image defect occurred due to the scraping of the photosensitive drum 3. Also, the charging bias voltage A
When the peak-to-peak voltage Vpp of the C component was constantly controlled at 1800 (V), no image defects occurred due to scraping of the photosensitive drum 3 up to 25,000 sheets. From around 15,000 sheets, a defective image due to charging failure due to surface contamination of the charging roller 4 occurred.

As described above, according to the present invention, by changing the voltage applied to the charging member and changing the applied voltage in accordance with the use condition of the process cartridge, the charging member can be shortened without shortening the life of the photosensitive drum. The formation of a defective image due to a charging failure due to surface contamination can be prevented.

In particular, in this embodiment, both members 30A and 30B are used by using a developer amount detecting means having a measuring electrode member (detecting member) 30A and a reference electrode member (comparing member) 30B.
The remaining amount of the developer in the developer container 8 is detected by comparing the electrostatic capacity of the developer container 8, and the reference electrode member (comparison electrode member) 30
B functions as an environment detecting means, and detects the environment in the vicinity of the developing means 7 by detecting its capacitance, so that extremely accurate detection of the remaining amount of the developer can be performed without being affected by environmental fluctuations. This can be realized, and the environment (humidity) in the vicinity of the developing means can be achieved without providing a dedicated environment sensor separately. Therefore,
The usage status of the process cartridge C can be detected at low cost and space saving.

As described above, according to the present invention, the use state of the process cartridge C, that is, the amount of the developer in the developer container 8 and the environment (humidity) near the developing means 7 are detected. However, the present invention is not limited to the means of the present embodiment. Cost, space, the accuracy of detecting the remaining amount of the developer, and the like, if allowable, a known developer remaining amount detecting unit, and a known environmental sensor such as a hygrometer may be used. Can be used. or,
The developer amount detecting means and the environment detecting means may both be provided in the process cartridge C, or one of them may be provided in the image forming apparatus main body.

Further, in this embodiment, the use condition of the process cartridge C is 60% or more of humidity and the remaining amount of the developer is 75%.
% Or less than 40% and the remaining amount of developer is 25% or less, the voltage applied to the charging roller 4 is changed. However, the present invention is not limited to this setting. It may be appropriately selected according to the hardness and surface properties of the charging roller 4 or the formulation of the developer, the life of the process cartridge C, the degree of contamination of the charging roller 4, and the like.

Embodiment 2 The image forming apparatus of this embodiment is basically the same as that of Embodiment 1 except for the control of the charging bias voltage applied to the charging roller 4. Therefore, members having the same functions and configurations are denoted by the same reference numerals, and detailed description is omitted.

In the first embodiment, the application of the charging bias voltage to the charging roller 4 is performed only by the so-called AC charging method. In this embodiment, however, the desired charging potential of the photosensitive drum 3 is changed to the discharge starting voltage. A so-called DC charging method in which a DC voltage obtained by adding Vd is applied to the charging roller 4 to charge the photosensitive drum 3 is also adopted according to the use condition of the process cartridge C. The structure is to extend the life.

FIG. 14 shows an image forming apparatus according to the present embodiment, in which 1000 g of the developer was initially charged and the life was 200 hours.
This shows how the charging roller 4 is stained when a durability test is performed up to the service life using 00 process cartridges C.
FIG. 14 shows a typical example of how the charging roller 4 becomes dirty in a high humidity environment and a low humidity environment.

In FIG. 14, the horizontal axis indicates the remaining amount of the developer in the developer container 8 of the process cartridge C, and the vertical axis indicates the amount of dirt on the charging roller 4. Also, the hatched area in the figure is
When the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 is low, and when the DC charging method is adopted, the range of the amount of dirt in which charging failure occurs due to surface contamination of the charging roller 4 is shown. .

FIG. 14 shows that in a low humidity environment, the surface contamination of the charging roller 4 becomes remarkable especially in the latter half of the use of the process cartridge C, and in a high humidity environment, particularly in the early stage of the use of the cartridge. It can be seen that the surface contamination tends to be remarkable.

From the results shown in FIG. 14 and the results of many experimental studies by the present inventor, in the image forming apparatus of this embodiment, the detecting member (measuring electrode member) 30 as the developer amount detecting means is used.
A, based on the detection result of the comparison member (reference electrode member) 30B, the usage status of the process cartridge
% Or more and the remaining amount of developer is 75% or more, or when it is determined that the humidity is 40% or less and the remaining amount of developer is 25% or less, the charging bias voltage applied to the charging roller 4 The peak-to-peak voltage Vpp of the AC component
(V), when the usage status of the process cartridge C is determined to be 60% or more in humidity and the remaining amount of the developer is 25% or less, or it is determined that the humidity is 40% or less and the remaining amount of the developer is 75% or more. In this case, the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 is set to 1800.
In (V), if it is determined that the usage status is other than that, D
It was controlled to use the C charging system.

The procedure for controlling the charging voltage applied to the charging roller 4 will be described. First, at the start of the image forming operation, the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 is set to 22000 (V). The use status of the process cartridge C is immediately detected. Based on this detection result, the peak-to-peak voltage Vpp of the AC component of the charging bias voltage applied to the charging roller 4 is set to 1800 (V).
, Or to change to the DC charging method, and if necessary, start image formation.

When the above control was performed and an image forming test was actually performed on 20,000 sheets in a high-temperature, high-humidity, and low-temperature, low-humidity environment, the charging roller 4 was contaminated to cause poor charging. No image defects such as density unevenness and toner adhesion (fogging) to the white portion occurred, and no image defects due to scraping of the photosensitive drum 3 occurred. Regarding the life of the photosensitive drum 3, the one obtained by changing the charging bias voltage applied to the charging roller 4 under the control of the present embodiment is the target life of 20,000 sheets of the process cartridge C used in the present embodiment. Was formed, and the formation of a defective image due to charging failure due to surface contamination of the charging roller 4 did not occur.

As described above, according to the present invention, by changing the voltage applied to the charging member 4 and changing the applied voltage according to the use condition of the process cartridge C, the life of the photosensitive drum 3 is not shortened. In addition, it is possible to prevent the formation of a defective image due to charging failure due to surface contamination of the charging member 4.

In this embodiment, as in the first embodiment, the use state of the process cartridge C, that is, the developer container 8
Although the detection member 30A and the comparison member 30B are used as the developer amount detecting means and the environment detecting means for detecting the amount of the developer inside and the environment (humidity) near the developing means 7, the means of the present embodiment is used. However, the present invention is not limited to this, and a known developer remaining amount detecting unit and a known environmental sensor such as a hygrometer can be used when the cost, space, detection accuracy of the remaining developer amount, and the like are acceptable.

In this embodiment, the use condition of the process cartridge C is 60% or more of humidity and the remaining amount of the developer is 7%.
5% or more, humidity 40% or less, and developer remaining amount 25%
If the humidity is determined to be 60% or less and the remaining amount of the developer is determined to be 25% or less,
% And the remaining amount of the developer is 75% or more, and when it is determined that the remaining amount is other than 75%, the charging roller 4
However, the present invention is not limited to this setting. For example, the hardness and surface properties of the charging roller 4 or the formulation of the developer, the life of the process cartridge C, and the contamination of the charging roller 4 May be appropriately selected depending on the degree of

In each of the above embodiments, a single color electrophotographic image forming apparatus of the process cartridge type is described. However, the principle of the present invention is applicable to an electrophotographic image forming apparatus not using the process cartridge type. By changing the charging voltage applied to the charging member as described in each of the above embodiments based on the remaining amount of the developer in the developer container and the environment (humidity) in the vicinity of the developing means, for example, An image forming apparatus in which a developing unit formed by means and a developer container is detachably attached to the image forming apparatus, or an image forming apparatus in which the developing unit is fixed to the image forming apparatus and the developer can be supplied. Also in the apparatus, it is possible to prevent the formation of a defective image due to charging failure due to contamination of the charging member and to reduce the shaving of the electrophotographic photosensitive member. Be apparent from the description of the embodiments, it is included in the present invention.

Further, the principle of the present invention is applied to an electrophotographic image forming apparatus having a plurality of developing units each having a developing means and a developer container, for example, capable of forming a full-color image. In each of the above-described embodiments, the detection is performed in the same manner as the usage of the process cartridge, and the amount of dirt on the charging member is estimated in accordance with the usage of each developing device. By changing
It is clear from the description of each of the above embodiments that it is possible to prevent formation of a defective image due to charging failure due to contamination of the charging member and to reduce shaving of the electrophotographic photoreceptor without further description, Included in the present invention.

[0104]

As described above, the electrophotographic image forming apparatus of the present invention comprises an electrophotographic photosensitive member, a charging member which is charged by contacting the surface of the electrophotographic photosensitive member, and a charging member which applies a voltage to the charging member. Voltage applying means, voltage changing means for changing a voltage applied from the charging voltage applying means to the charging member, latent image forming means for forming a latent image on the electrophotographic photosensitive member, and a latent image formed on the electrophotographic photosensitive member Means for visualizing the image with a developer, a developer container for containing the developer and supplying the developer to the developing means, and a developer amount detector for sequentially detecting the amount of the developer in the developer container Means, and an environment detecting means for detecting an environment in the vicinity of the developing means, wherein the voltage changing means is a voltage applied from the voltage applying means to the charging member based on the detection results of the developer amount detecting means and the environment detecting means. And the present invention According to the present invention, a process cartridge type electrophotographic image forming apparatus, a process cartridge, and a charging device to which the principle of the present invention is applied are provided. It is possible to minimize the shortening of the life of the photographic photoreceptor and prevent charging failure due to contamination of the charging member surface.

[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 schematic configuration diagram showing the vicinity of a charging device according to the present invention.

FIG. 3 is a perspective view of a developer container for describing a developer amount detecting unit according to the present invention.

FIG. 4 is a front view showing one embodiment of a measurement electrode member (detection member) and a reference electrode member (comparative member).

FIG. 5 is a graph for explaining a principle of detecting a developer amount according to the present invention.

FIG. 6 is a graph for explaining a principle of detecting a developer amount according to the present invention.

FIG. 7 is a two-side view showing a developer container for describing one embodiment of a developer amount detecting unit according to the present invention.

8A and 8B are perspective views of a developer container for explaining another embodiment of the developer amount detecting means according to the present invention.

FIGS. 9A and 9B are diagrams for explaining one example of an arrangement configuration of a measurement electrode member and a reference electrode member, and FIGS.

FIG. 10 is a diagram illustrating an example of a developer amount display.

FIG. 11 is a view showing another embodiment of a developer amount display.

FIG. 12 is a diagram showing another embodiment of the developer amount display.

FIG. 13 is a graph illustrating an example of a relationship between a developer remaining amount and a stain amount of a charging roller.

FIG. 14 is a graph illustrating an example of a relationship between a developer remaining amount and a stain amount of a charging roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical means (exposure means) 3 Photoconductor drum (electrophotographic photosensitive body) 4 Charging roller (charging member) 5 Fixing means 7 Developing means 8 Developer container (developer accommodating part) 9 Developing means 14 Transfer roller (Transfer means) 15) Fixing device 16 Cleaning means 20 High voltage power supply (voltage applying means) 22 CPU (control means) 30A Measurement electrode member (detection member) 30B Reference electrode member (comparison member)

Claims (21)

[Claims] 1. An electrophotographic image forming apparatus for forming an image on a recording medium, comprising: an electrophotographic photoreceptor; a charging member that contacts and charges the electrophotographic photoreceptor surface; and applies a voltage to the charging member. Charging voltage applying means, voltage changing means for changing the voltage applied from the charging voltage applying means to the charging member, latent image forming means for forming a latent image on the electrophotographic photosensitive member, and the electrophotographic photosensitive member Developing means for visualizing the latent image formed in the developer with a developer, a developer container for containing the developer and supplying the developer to the developing means, and a developer amount in the developer container. A developer amount detecting means for sequentially detecting, and an environment detecting means for detecting an environment in the vicinity of the developing means, wherein the voltage changing means is adapted to detect a result of the developer amount detecting means and the environment detecting means. Based on the voltage Electrophotographic image forming apparatus characterized by changing the voltage applied to the charging member from the pressurized section. 2. The method according to claim 1, wherein the voltage applying unit is capable of applying a DC and an AC voltage to the charging member, and the voltage changing unit is configured to apply a peak of the AC voltage based on a detection result of the developer amount detecting unit and the environment detecting unit. 2. The electrophotographic image forming apparatus according to claim 1, wherein the inter-voltage is changed. A plurality of developer units each including the developing unit and the developer container, wherein the plurality of developer units are provided for at least the plurality of developing units; 3. The voltage applied to the charging member is changed based on the detection result of (1).
Electrophotographic image forming apparatus. 4. A detecting member provided with an electrode having at least a pair of parts arranged at a location in contact with the developer as at least a pair of the developer amount detecting means and the environment detecting means, And a comparison member provided with an electrode having at least a pair of portions juxtaposed at a predetermined interval. The comparison member includes an electrostatic capacitance of the detection member as the developer amount detection unit. The amount of the developer in the developer container is detected by detecting and comparing the capacitance of the member and the amount of the developer in the developer container, and the vicinity of the developing unit is detected by detecting the capacitance of the comparison member as the environment detecting unit. The environment of Claim 1 is detected.
An electrophotographic image forming apparatus according to 2 or 3. 5. A process cartridge detachable from an electrophotographic image forming apparatus main body, comprising: an electrophotographic photosensitive member; and a process unit acting on the electrophotographic photosensitive member.
A charging member that is charged by contacting at least the surface of the electrophotographic photosensitive member, a developing unit that visualizes an electrostatic latent image formed on the electrophotographic photosensitive member with a developer, A developer container for supplying a developer to the electrophotographic image forming apparatus main body, wherein the charging member has the process cartridge mounted on the electrophotographic image forming apparatus main body. A process cartridge, wherein a voltage changed according to a use state of the process cartridge based on an amount of the developer in the developer container and an environment near the developing unit is applied. 6. A DC and AC voltage is applied to the charging member in a state where the process cartridge is mounted on the electrophotographic image forming apparatus, and the amount of developer in the developer container and the developing unit 6. The process cartridge according to claim 5, wherein a peak-to-peak voltage of the AC voltage is changed according to a use condition of the process cartridge based on a nearby environment. 7. The charging member further includes: a developer amount detecting unit for sequentially detecting a developer amount in the developer container; and an environment detecting unit for detecting an environment near the developing unit. In the state where the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the process based on the amount of developer in the developer container and the environment near the developing means in the main body of the electrophotographic image forming apparatus. 7. The process cartridge according to claim 5, wherein a voltage changed according to a use state of the cartridge is applied. 8. An environment detecting device for detecting an amount of the developer in the developing container, wherein the charging member detects an environment in which the process cartridge detects an environment near the developing device. The state of use of the process cartridge based on the amount of developer in the developer container and the environment in the vicinity of the developing means in the electrophotographic image forming apparatus main body in a state where the process cartridge is mounted on the electrophotographic image forming apparatus main body having the means. 7. The process cartridge according to claim 5, wherein a voltage changed according to the voltage is applied. 9. An amount of developer detecting means for detecting an amount of developer in the developer container, wherein the charging member includes an environment detecting means for detecting an environment in the vicinity of the developing means. When the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the process state of the process cartridge based on the amount of the developer in the developer container and the environment in the vicinity of the developing means in the main body of the electrophotographic image forming apparatus. 7. The process cartridge according to claim 5, wherein a voltage changed according to the applied voltage is applied. 10. A detecting member provided with an electrode having at least a pair of parts arranged side by side with a predetermined interval at least in contact with the developer, and at least a pair of predetermined intervals arranged at a location not in contact with the developer. A comparison member with an electrode having portions juxtaposed with
The charging member detects and compares the capacitances of the detection member and the comparison member with the main body of the electrophotographic image forming apparatus while the process cartridge is mounted on the main body of the electrophotographic image forming apparatus. The remaining amount of the developer in the developer container detected by the above, and the usage state of the process cartridge based on the environment near the developer means detected by detecting the capacitance of the comparison member. 7. The process cartridge according to claim 5, wherein a voltage changed according to the applied voltage is applied. 11. A detecting member provided with an electrode which is disposed at a position in contact with the developer and has at least a pair of portions arranged side by side at a predetermined interval, wherein the charging member is provided with the process cartridge and the developer. The electrophotographic image forming apparatus main body is mounted on an electrophotographic image forming apparatus main body having a comparison member provided with an electrode having at least a pair of electrodes arranged side by side at predetermined intervals. The remaining amount of developer in the developer container detected by detecting and comparing the capacitances of the detection member and the comparison member, and the capacitance of the comparison member were detected. 7. The process cartridge according to claim 5, wherein a voltage changed according to a use state of the process cartridge based on an environment near the developer unit is applied. Cartridge. 12. An electrophotographic image forming apparatus in which a process cartridge is detachable and which forms an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; and a process means acting on the electrophotographic photosensitive member. of,
A charging member that is charged by contacting at least the surface of the electrophotographic photosensitive member, a developing unit that visualizes an electrostatic latent image formed on the electrophotographic photosensitive member with a developer, Mounting means for removably mounting a process cartridge having a developer container for supplying a developer to the means, (b) in a state where the process cartridge is mounted on the electrophotographic image forming apparatus main body, Charging voltage applying means for applying a voltage to the charging member; (c) voltage changing means for changing a voltage applied from the charging voltage applying means to the charging member; and (d) electrostatic latent on the electrophotographic photosensitive member. A latent image forming unit for forming an image, and wherein the process cartridge is mounted on the electrophotographic image forming apparatus main body,
The voltage changing unit changes the voltage applied from the charging voltage applying unit to the charging member in accordance with the use amount of the process cartridge based on the amount of the developer in the developer container and the environment near the developing unit. An electrophotographic image forming apparatus, comprising: 13. The developer applying device according to claim 1, wherein the voltage applying unit is configured to apply a DC voltage and an AC voltage to the charging member in a state where the process cartridge is mounted on the electrophotographic image forming apparatus. 13. The electrophotographic image forming apparatus according to claim 12, wherein the peak-to-peak voltage of the AC voltage is changed in accordance with a use condition of the process cartridge based on an environment near the developing unit. 14. A process cartridge according to claim 1, further comprising: a developer amount detecting means for sequentially detecting a developer amount in the developer container; and an environment detecting means for detecting an environment in the vicinity of the developing means. The voltage changing unit is configured to apply the charging voltage in accordance with a usage amount of the process cartridge based on an amount of the developer in the developer container and an environment near the developing unit in a state where the charging voltage is applied to the image forming apparatus. 14. An electrophotographic image forming apparatus according to claim 12, wherein a voltage applied from said means to said charging member is changed. 15. A process cartridge further comprising an environment detecting means for detecting an environment near the developing means, and further comprising a developer amount detecting means for sequentially detecting an amount of developer in the developing container. In a state where the charging unit is mounted on the electrophotographic image forming apparatus main body, the voltage changing unit is configured to charge the charge according to the amount of the developer in the developer container and the use state of the process cartridge based on an environment near the developing unit. 14. An electrophotographic image forming apparatus according to claim 12, wherein a voltage applied from said voltage applying means to said charging member is changed. 16. The process cartridge according to claim 1, further comprising: a developer amount detecting unit configured to detect an amount of the developer in the developer container, wherein the process cartridge further includes an environment detecting unit configured to detect an environment near the developing unit. In a state where the charging unit is mounted on the main body of the photographic image forming apparatus, the voltage changing unit is configured to control the charging voltage in accordance with a developer amount in the developer container and a use state of the process cartridge based on an environment near the developing unit. 14. An electrophotographic image forming apparatus according to claim 12, wherein a voltage applied from said application means to said charging member is changed. 17. A detecting member provided with an electrode having at least a pair of juxtaposed portions arranged in contact with the developer and having at least a pair of juxtaposed portions arranged at a location not contacting the developer, and Detecting a capacitance of the detection member and the comparison member in a state where the process cartridge further includes a comparison member having an electrode having a portion arranged side by side with the electrophotographic image forming apparatus main body. Use of the process cartridge based on the remaining amount of the developer in the developer container detected by comparison and the environment near the developer unit detected by detecting the capacitance of the comparison member 14. The battery according to claim 12, wherein the voltage changing means changes a voltage applied to the charging member from the charging voltage applying means according to a situation. Child photographic image forming apparatus. 18. A device which is disposed at a position not in contact with the developer,
The apparatus further includes a comparison member including an electrode having at least a pair of parts arranged side by side at a predetermined interval, and an electrode having a pair of parts arranged at least at a pair of parts arranged at a predetermined distance. The developer container detected by detecting and comparing the capacitances of the detection member and the comparison member in a state where the process cartridge having the detection member is mounted on the main body of the electrophotographic image forming apparatus. The voltage changing unit is configured to operate according to the usage state of the process cartridge based on the remaining amount of the developer and the environment near the developer unit detected by detecting the capacitance of the comparison member. 14. An electrophotographic image forming apparatus according to claim 12, wherein a voltage applied from said charging voltage applying means to said charging member is changed. 19. A charging device for charging an electrophotographic photoreceptor, a charging member that contacts and charges the electrophotographic photoreceptor, a charging voltage applying unit that applies a voltage to the charging member, and the charging voltage applying unit. And a voltage changing means for changing a voltage applied to the charging member from the environment, and an environment in the vicinity of the developing means for developing an electrostatic latent image formed on the electrophotographic photoreceptor with a developer, and a developer. A charging device that changes a voltage applied from the charging voltage applying unit to the charging member based on a developer amount in a developer container that stores the developer and supplies the developer to the developing unit. . 20. An environment in the vicinity of the developing means, wherein the voltage applying means can apply DC and AC voltages to the charging member, and develops an electrostatic latent image formed on the electrophotographic photosensitive member with a developer. And, based on the amount of developer in a developer container that contains the developer and supplies the developer to the developing unit,
20. The charging device according to claim 19, wherein a peak-to-peak voltage of the AC voltage is changed. 21. The charging device according to claim 19, wherein the charging member is a rotator having an elastic layer in contact with the electrophotographic photosensitive member.