JP2001159839A - Image forming device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of realizing the reduction of the cost of a power source part for a member requiring the application of voltage in the image forming device and a process cartridge using a scorotron type electrifier or the like. SOLUTION: An aperture part B is provided on the shield 32 of a scorotron type electrifier 30 and a charge capturing electrode 90 is provided to cover the aperture part B. Furthermore, the electrode 90 is electrically connected to a plate 84 of a brush member 86 in a paper powder removing device 80. Thus, the voltage having the same polarity as the electrification polarity of toner is applied to the member 86 without providing a power source for the member 86.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and a process cartridge for forming an image by transferring a developer to a recording medium, and more particularly, to an image forming apparatus using a scorotron type or corotron type charger. It belongs to the technical field of a process cartridge.

[0002]

2. Description of the Related Art Conventionally, a photosensitive member such as a photosensitive drum on which an electrostatic latent image is formed on a surface thereof, a scorotron type charger for uniformly charging the surface of the photosensitive member by corona discharge,
An electrostatic latent image forming means for forming the electrostatic latent image on the photoreceptor surface after being charged by the charger; and a developer such as toner on the electrostatic latent image formed by the electrostatic latent image forming means There is known an image forming apparatus provided with a developing unit that transports and develops the developer, and a supply unit that supplies a developer to the developing unit.

In this type of image forming apparatus, an electrostatic latent image is formed on a surface of a photoreceptor uniformly charged by a charger by an electrostatic latent image forming unit, and charged by frictional charging or the like by a developing unit. An image is formed by developing the electrostatic latent image with a developer and subsequently transferring the developer to a recording medium.

Therefore, in order to form a good image in this type of image forming apparatus, it is essential to first uniformly charge the photoreceptor with a charger. Therefore, a scorotron type charger excellent in charging uniformity has been generally used. This scorotron-type charger, which applies a high voltage to a thin tungsten wire of, for example, 30 to 100 μm to generate a corona discharge to charge the photoreceptor, is capable of not only uniform charging but also non-charging. Since the photoreceptor is charged by the contact, there is an advantage that the deterioration due to the adhesion of the toner is small and the durability is excellent as compared with the charging device by the contact charging.

[0005]

Incidentally, in the above-described electrophotographic image forming apparatus, there are many members which need to apply a voltage in addition to a photosensitive member, a charger, a developing roller and the like. Provided. For example, it is applied to a paper dust removing means for removing charged paper dust from the photoconductor, a fixing device to which a voltage is applied for the purpose of preventing electrostatic offset, and a developing roller of a non-magnetic one-component developing device. It is a layer thickness regulating blade or a sealing member to be brought into contact.

[0006] The voltage applied to these members is not limited as long as the polarity is determined.
Conventionally, a power supply for these members is provided in the main body of the image forming apparatus, resulting in an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and in an image forming apparatus and a process cartridge using a scorotron-type charger, the cost of a power supply portion for a member requiring application of a voltage is required. It is an object of the present invention to provide an image forming apparatus and a process cartridge capable of reducing the number of images.

[0008]

According to an aspect of the present invention, there is provided an image forming apparatus, comprising: a charger having a corona discharge electrode; and a voltage applying member which contributes to image formation at a predetermined potential. An image forming apparatus comprising: a charge trapping electrode facing the corona discharge electrode in addition to the electrodes constituting the charger, wherein the voltage applying member and the charge trapping electrode are electrically connected. It is characterized by the following.

According to the image forming apparatus of the present invention, when a high voltage is applied to the corona discharge electrode of the charger, the corona discharge electrode generates a corona discharge, for example, causing the electrostatic latent image carrier such as a photoconductor to move. Charge. On the other hand, the corona discharge electrode
As an electrode other than the electrodes constituting the charger, a charge trapping electrode is opposed, and the charge trapping electrode is charged to the same polarity as the electrostatic latent image carrier. Since the charge trapping electrode is electrically connected to the voltage-applying member, a voltage is applied to the voltage-applying member, and the voltage is set to a predetermined potential. Thereby, for example, a predetermined potential relationship between the member that maintains a predetermined potential relationship with the electrostatic latent image carrier and the voltage-applied member, or between the electrostatic latent image carrier and the voltage-applied member. Is kept. Thus, an appropriate voltage is applied to the voltage-applied member without providing a power supply dedicated to the voltage-applied member.

According to a second aspect of the present invention, there is provided an image forming apparatus according to the first aspect, wherein the charger comprises a corotron charger using a corona discharge wire for the corona discharge electrode. Alternatively, it is a scorotron charger.

According to the image forming apparatus of the present invention, when a voltage is applied to a corona discharge wire as a corona discharge electrode in a corotron charger or a scorotron charger, the corona discharge wire generates a corona discharge, and a photoconductor or the like is generated. Is charged. On the other hand, since the corona discharge wire performs a substantially uniform discharge in all directions around the corona discharge wire, the charge trapping electrode faces the corona discharge wire as an electrode other than the electrodes constituting the corotron charger or the scorotron charger. In such a case, the corona discharge wire satisfactorily charges the charge trapping electrode. Therefore, an appropriate voltage is applied to the voltage receiving member electrically connected to the charge trapping electrode.

According to a third aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect, wherein the polarity of the voltage applied to the charger is positive. Features.

According to the third aspect of the present invention, since the polarity of the voltage applied to the charger is positive, the polarity of the voltage of the charge trapping electrode charged by the charger, and further, the electric trapping electrode and the electrical The polarity of the voltage of the voltage-applied member connected to is also positive. On the other hand, in a general reversal developing method, the developer is also charged to the same polarity as the voltage polarity of the charger.
Therefore, the voltage-applying member is a member that removes paper dust that is charged to a polarity opposite to that of the developer at the time of transfer, a seal member that prevents leakage of the developer, or a reverse-polarized charged or uncharged developer It is suitably used widely in an image forming apparatus as a developer layer thickness regulating member or the like for preventing passage of the developer. Also, the charging by the positive polarity corona discharge has an advantage that the amount of generated ozone is significantly smaller than the charging by the negative polarity corona discharge.

According to a fourth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to third aspects, wherein the image forming apparatus has a charger having a corona discharge electrode. And a voltage-applying member that contributes to image formation at a predetermined potential in a process cartridge, and the process cartridge is detachably provided. The charge trapping electrode provided to face the corona discharge electrode and electrically connected to the voltage applying member is provided in the process cartridge.

According to the image forming apparatus of the present invention, when a high voltage is applied to the corona discharge electrode of the charger provided in the process cartridge, the corona discharge electrode generates a corona discharge. The electrostatic latent image carrier such as a photoconductor provided therein is charged.
On the other hand, a charge trapping electrode is opposed to the corona discharge electrode as an electrode other than the electrodes constituting the charger, and the charge trapping electrode is charged to the same polarity as the electrostatic latent image carrier. Since the charge trapping electrode is electrically connected to the voltage-applying member, a voltage is applied to the voltage-applying member, and the voltage is set to a predetermined potential. Thereby, for example, a predetermined potential is applied between a member that maintains a predetermined potential relationship with respect to the electrostatic latent image carrier and the voltage-applied member, or between the electrostatic latent image carrier and the voltage-applied member. Relationships are maintained. Thus, an appropriate voltage is applied to the voltage-applied member without providing a power supply dedicated to the voltage-applied member. Since the charge trapping electrode and the voltage applying member are both provided in the process cartridge, a contact electrode for applying a voltage to the voltage applying member is provided between the process cartridge and the image forming apparatus. There is no need to provide

According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to any one of the first to fourth aspects, the voltage-applying member is provided with the electrostatic latent image carrier. The paper dust removing means is disposed opposite to the body.

According to the image forming apparatus of the present invention, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage applying member electrically connected to the electric trapping electrode are charged. It has the same polarity as the polarity of the voltage of the container. On the other hand, in a general reversal developing method, the developer is also charged to the same polarity as the voltage polarity of the charger. Therefore, the paper dust removing means as the voltage applying member is charged to the same polarity as the charged polarity of the developer, and the paper dust charged to the opposite polarity to the developer at the time of transfer is reliably charged with the electrostatic latent image. Remove from body.

According to a sixth aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to the fifth aspect, the paper dust removing means is grounded via a high resistance. And

According to the image forming apparatus of the present invention, since the paper dust removing means is grounded via a high resistance, for example, in a high humidity environment, the resistance value of the paper dust removing means is reduced. Even if it is lowered, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier,
The current will flow through the high resistance. as a result,
An image defect is reliably prevented without damaging the electrostatic latent image carrier.

According to a seventh aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to the fifth aspect, the paper dust removing means is connected to a grid electrode of the charger through a high resistance. It is characterized by being electrically connected.

According to the image forming apparatus of the present invention, since the paper dust removing means is electrically connected to the grid electrode of the charger through a high resistance, the paper dust removing means can be used in a high humidity environment, for example. Even when the resistance value of the paper dust removing unit decreases, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. Become. As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Also, since the paper dust removing means and the grid electrode are electrically connected via the high resistance,
The value of the voltage applied by the paper dust removing unit is defined by the voltage value of the grid electrode. For example, even in a high humidity environment, the voltage value applied by the paper dust removing unit is stable. Will do.

According to an eighth aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to any one of the first to fourth aspects, the voltage-applying member is provided with the electrostatic latent image carrier. It is a member provided so as to rub against a developer carrying member which holds a developer while maintaining a predetermined potential relationship with the body.

According to the image forming apparatus of the present invention, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage applying member electrically connected to the electric trapping electrode are equal to each other. It has the same polarity as the polarity of the voltage of the container. On the other hand, in a general reversal developing method, the developer is also charged to the same polarity as the voltage polarity of the charger. Therefore, when a member provided so as to rub against the developer carrier is used as the voltage-applied member, for example, a voltage having the same polarity as the developer acts on the developer in the seal portion, Developer leakage is prevented. In the developer layer thickness regulation section,
A voltage having the same polarity as the normally charged developer acts on the oppositely charged or uncharged developer, and the passage of the oppositely charged or uncharged developer is reliably prevented.

According to a ninth aspect of the present invention, there is provided a process cartridge comprising:
In order to solve the above-mentioned problem, a process cartridge which includes a scorotron charger having a corona discharge wire, and a voltage-applying member which contributes to image formation at a predetermined potential, and is detachable from an image forming apparatus. And a charge trapping electrode facing the corona discharge wire in addition to the electrodes constituting the scorotron charger, and the voltage applying member and the charge trapping electrode are electrically connected.

According to the process cartridge of the present invention, when a high voltage is applied to the corona discharge wire of the scorotron charger, the corona discharge wire generates a corona discharge and, for example, an electrostatic latent image carrier such as a photosensitive member. Is charged. On the other hand, a charge trapping electrode is opposed to the corona discharge wire as an electrode other than the electrodes constituting the charger, and the charge trapping electrode is charged similarly to the electrostatic latent image carrier. Since the charge trapping electrode is electrically connected to the voltage-applying member, a voltage is applied to the voltage-applying member, and the voltage is set to a predetermined potential. Thereby, for example, a predetermined potential is applied between a member that maintains a predetermined potential relationship with respect to the electrostatic latent image carrier and the voltage-applied member, or between the electrostatic latent image carrier and the voltage-applied member. Relationships are maintained. In particular, since the corona discharge wire discharges substantially uniformly in all directions around the corona discharge wire, even when the charge trapping electrode is opposed to the corona discharge wire as an electrode other than the electrode constituting the scorotron charger, the corona discharge wire is not charged. The discharge wire charges the charge trapping electrode well.
Therefore, an appropriate voltage is applied to the voltage receiving member electrically connected to the charge trapping electrode.
Since the charge trapping electrode and the voltage applying member are both provided in the process cartridge, a contact electrode for applying a voltage to the voltage applying member is provided between the process cartridge and the image forming apparatus. There is no need to provide

According to a tenth aspect of the present invention, there is provided a process cartridge according to the ninth aspect, wherein the polarity of the voltage applied to the charger is positive.

According to the tenth aspect of the present invention, since the polarity of the voltage applied to the charger is positive, the polarity of the voltage of the charge trapping electrode charged by the charger, and further, the charge trapping electrode is electrically connected to the charge trapping electrode. The polarity of the voltage of the connected voltage applying member also becomes positive. On the other hand, in a general reversal developing method, the developer is also charged to the same polarity as the voltage polarity of the charger. Therefore, the voltage-applying member is a member that removes paper dust that is charged to a polarity opposite to that of the developer at the time of transfer, a seal member that prevents leakage of the developer, or a reverse-polarized charged or uncharged developer It is suitably used widely in a process cartridge as a developer layer thickness regulating member or the like for preventing passage of the developer. Also, the charging by the positive polarity corona discharge has an advantage that the amount of generated ozone is significantly smaller than the charging by the negative polarity corona discharge.

According to an eleventh aspect of the present invention, in order to solve the above-mentioned problem, in the process cartridge according to the ninth or tenth aspect, the voltage applying member is arranged to face the electrostatic latent image carrier. It is a paper dust removing means.

According to the eleventh aspect of the present invention, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage-applying member electrically connected to the electric trapping electrode are different from each other. Has the same polarity as the voltage. On the other hand, in a general reversal developing method, the developer is also charged to the same polarity as the voltage polarity of the charger. Therefore, the paper dust removing means as the voltage applying member is charged to the same polarity as the charged polarity of the developer, and the paper dust charged to the opposite polarity to the developer at the time of transfer is reliably charged with the electrostatic latent image. Remove from body.

According to a twelfth aspect of the present invention, there is provided a process cartridge according to the eleventh aspect, wherein the paper dust removing means is grounded via a high resistance. .

According to the twelfth aspect of the present invention, since the paper dust removing means is grounded via a high resistance, the resistance value of the paper dust removing means decreases, for example, in a high humidity environment. Even in this case, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. As a result, without damaging the electrostatic latent image carrier,
Image defects are reliably prevented.

According to a thirteenth aspect of the present invention, there is provided a process cartridge according to the eleventh aspect, wherein the paper dust removing means electrically connects a grid electrode of the charger via a high resistance. Is connected to the terminal.

According to the process cartridge of the present invention, since the paper dust removing means is electrically connected to the grid electrode of the charger via a high resistance, for example, in a high humidity environment, Even if the resistance value of the paper dust removing unit decreases, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. . As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Further, since the paper dust removing means and the grid electrode are electrically connected via the high resistance, the value of the voltage applied by the paper dust removing means is the voltage value of the grid electrode. The voltage value applied by the paper dust removing means becomes stable, for example, even in a high humidity environment.

According to a fourteenth aspect of the present invention, there is provided a process cartridge according to the ninth or tenth aspect, wherein the voltage-applying member is provided at a predetermined distance from the electrostatic latent image carrier. And a member provided so as to rub against a developer carrying member that holds the developer while maintaining the potential relationship.

According to the process cartridge of the present invention, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage-applying member electrically connected to the electric trapping electrode are determined by the charging device. Has the same polarity as the voltage. On the other hand, in a general reversal developing method, the developer is also charged to the same polarity as the voltage polarity of the charger. Therefore, when a member provided so as to rub against the developer carrier is used as the voltage-applied member, for example, a voltage having the same polarity as the developer acts on the developer in the seal portion,
Developer leakage is prevented. In the developer layer thickness regulation section, a voltage having the same polarity as the normally charged developer acts on the oppositely charged or uncharged developer, so that the oppositely charged or uncharged developer passes. It is surely blocked.

According to a fifteenth aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to any one of the first to fourth aspects, the voltage-applying member is provided with the electrostatic latent image carrier. It is a static eliminator disposed opposite to the body.

According to the image forming apparatus of the present invention,
The polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage applying member electrically connected to the electric trapping electrode are the same as the polarity of the voltage of the charger. On the other hand, an electrostatic latent image carrier such as a photoconductor is also charged to the same polarity as the voltage polarity of the charger, but the surface potential of the electrostatic latent image carrier after the transfer step is such that a developer image is formed. The portion that has been set has a lower potential than the portion that has not been formed. Therefore, in the case where the static eliminator disposed opposite to the electrostatic latent image carrier is used as the voltage applying member, the transfer is performed in the static eliminator, which is a rubbing portion between the static eliminator and the electrostatic latent image carrier. The static elimination action is performed so as to eliminate unevenness of the surface potential between the image portion and the non-image portion. As a result, in the subsequent charging step, the surface of the electrostatic latent image carrier is uniformly charged.

According to a sixteenth aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to any one of the first to fourth aspects, the voltage-applying member is provided with the electrostatic latent image carrier. Paper dust removing means arranged opposite to the body, including static elimination means arranged opposite to the electrostatic latent image carrier,
As the charge trapping electrode, two types of charge trapping electrodes, one for the paper dust removing unit and one for the charge removing unit, are included.

According to the image forming apparatus of the sixteenth aspect,
The polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage applying member electrically connected to the electric trapping electrode are the same as the polarity of the voltage of the charger. The paper dust removing means as the voltage applying member surely removes the paper dust charged to the same polarity as the charged polarity of the developer and charged to the opposite polarity to the developer from the electrostatic latent image carrier. In addition, the charge removing means as the voltage applying member has a higher potential than the portion where the developer image was formed on the electrostatic latent image carrier after the transfer process, and based on the potential of the portion. return. Further, since the supply of the voltage to the paper dust removing means and the electricity removing means is performed by two kinds of charge trapping electrodes, it is possible to supply a voltage having a value corresponding to each of the paper dust removing and electricity removing.

According to a seventeenth aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to any one of the first to fourth aspects, the voltage-applying member is provided with the electrostatic latent image carrier. Paper dust removing means arranged opposite to the body, static elimination means arranged opposite to the electrostatic latent image carrier, and carrying a developer while maintaining a predetermined potential relationship between the electrostatic latent image carrier and the developer A rubbing member provided so as to rub against the developer carrier; and as the charge trapping electrode, three kinds of charges of the paper dust removing means, the charge removing means, and the rubbing member. It is characterized by including a capture electrode.

According to the image forming apparatus of the seventeenth aspect,
The polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage applying member electrically connected to the electric trapping electrode are the same as the polarity of the voltage of the charger. The paper dust removing means as the voltage applying member surely removes the paper dust charged to the same polarity as the charged polarity of the developer and charged to the opposite polarity to the developer from the electrostatic latent image carrier. In addition, the charge removing means as the voltage applying member has a higher potential than the portion where the developer image was formed on the electrostatic latent image carrier after the transfer process, and based on the potential of the portion. return. Further, when a rubbing member provided so as to rub against the developer carrier is used as the voltage applying member, for example, a voltage having the same polarity as the developer acts on the developer in the seal portion. In addition, developer leakage is prevented. In the developer layer thickness regulation section, a voltage having the same polarity as the normally charged developer acts on the oppositely charged or uncharged developer, so that the oppositely charged or uncharged developer passes. It is surely blocked. In addition, since the supply of the voltage to the paper dust removing means, the electricity removing means, and the rubbing member is performed by three kinds of charge trapping electrodes, the paper dust removing means, the electricity removing means, the layer thickness regulation or the sealing are performed in accordance with each. Voltage can be supplied.

In order to solve the above-mentioned problem, the image forming apparatus according to the present invention may be arranged such that the paper dust removing means is grounded via a high resistance. It is characterized by.

According to the image forming apparatus of the present invention,
Since the paper dust removing unit is grounded via a high resistance, for example, in a high humidity environment, even when the resistance value of the paper dust removing unit decreases, the paper dust removing unit may No large current flows to the electrostatic latent image carrier,
The current will flow through the high resistance. as a result,
An image defect is reliably prevented without damaging the electrostatic latent image carrier.

According to a nineteenth aspect of the present invention, in order to solve the above problem, in the image forming apparatus according to the sixteenth or seventeenth aspect, the paper dust removing means includes a grid of the charger through a high resistance. It is characterized by being electrically connected to the electrode.

According to the image forming apparatus of the nineteenth aspect,
Since the paper dust removing unit is electrically connected to the grid electrode of the charger via a high resistance, for example, when the resistance value of the paper dust removing unit is reduced in a high humidity environment. However, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Also, since the paper dust removing means and the grid electrode are electrically connected via the high resistance,
The value of the voltage applied by the paper dust removing unit is defined by the voltage value of the grid electrode. For example, even in a high humidity environment, the voltage value applied by the paper dust removing unit is stable. Will do.

According to a twentieth aspect of the present invention, in the image forming apparatus,
In order to solve the problem, any one of claims 15 to 19
In the image forming apparatus described above, the static elimination unit has a resistance.
10 ^Two-10⁸Ωcm conductive film
Features.

According to the image forming apparatus of the twentieth aspect,
Since the static eliminator is a conductive film member having a resistance of 10 ² to 10 ⁸ Ωcm, for example, in a high-humidity environment, even when the resistance of the static eliminator decreases, a certain high resistance is maintained. Therefore, a large current does not flow from the charge removing unit to the electrostatic latent image carrier. As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier.

In the image forming apparatus according to a twenty-first aspect, in the image forming apparatus according to the twentieth aspect, the static elimination means also serves as a paper dust removing means arranged to elastically contact the electrostatic latent image carrier. It is characterized by the following.

According to the image forming apparatus of the twenty-first aspect,
The static elimination means also serves as a paper dust removing means arranged to be in elastic contact with the electrostatic latent image carrier, so that the surface of the electrostatic latent image carrier can be reliably secured without increasing the size and complexity of the apparatus. Can be neutralized.

According to a twenty-second aspect of the present invention, there is provided a process cartridge according to the ninth or tenth aspect, wherein the voltage applying member is disposed to face the electrostatic latent image carrier. It is a static elimination means.

According to the process cartridge of the present invention, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage-applying member electrically connected to the electric trapping electrode are determined by the charging device. Has the same polarity as the voltage. On the other hand, an electrostatic latent image carrier such as a photoconductor is also charged to the same polarity as the voltage polarity of the charger, but the surface potential of the electrostatic latent image carrier after the transfer step is such that a developer image is formed. The portion that has been set has a lower potential than the portion that has not been formed. Therefore, in the case where the static eliminator disposed opposite to the electrostatic latent image carrier is used as the voltage applying member, the transfer is performed in the static eliminator, which is a rubbing portion between the static eliminator and the electrostatic latent image carrier. The static elimination action is performed so as to eliminate unevenness of the surface potential between the image portion and the non-image portion. As a result, in the subsequent charging step, the surface of the electrostatic latent image carrier is uniformly charged.

According to a twenty-third aspect of the present invention, in order to solve the above-mentioned problem, in the process cartridge according to the ninth or tenth aspect, the voltage applying member is disposed so as to face the electrostatic latent image carrier. Paper dust removing means, and static elimination means arranged opposite to the electrostatic latent image carrier, and as the charge trapping electrode, two kinds of charge trapping electrodes for the paper dust removing means and for the charge eliminating means It is characterized by including.

According to the process cartridge of the twenty-third aspect, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage-applying member electrically connected to the electric trapping electrode are determined by the charging device. Has the same polarity as the voltage. The paper dust removing means as the voltage applying member surely removes the paper dust charged to the same polarity as the charged polarity of the developer and charged to the opposite polarity to the developer from the electrostatic latent image carrier. Further, the charge removing means as the voltage applying member makes the surface potential unevenness of the electrostatic latent image carrier after the transfer process uniform. Further, since the supply of the voltage to the paper dust removing means and the electricity removing means is performed by two kinds of charge trapping electrodes, it is possible to supply a voltage having a value corresponding to each of the paper dust removing and electricity removing.

According to a twenty-fourth aspect of the present invention, there is provided a process cartridge according to the ninth or tenth aspect, wherein the voltage-applying member is disposed to face the electrostatic latent image carrier. Paper dust removing means, static elimination means arranged opposite to the electrostatic latent image carrier, and a developer carrier which carries a developer while maintaining a predetermined potential relationship with the electrostatic latent image carrier. , A rubbing member provided so as to rub, and as the charge trapping electrode, three types of charge trapping electrodes for the paper dust removing means, the charge eliminating means, and the rubbing member. Features.

According to a twenty-fourth aspect of the present invention, the polarity of the voltage of the charge trapping electrode charged by the charger and the polarity of the voltage of the voltage-applying member electrically connected to the electric trapping electrode are different from each other. Has the same polarity as the voltage. The paper dust removing means as the voltage applying member surely removes the paper dust charged to the same polarity as the charged polarity of the developer and charged to the opposite polarity to the developer from the electrostatic latent image carrier. In addition, the charge removing means as the voltage applying member has a higher potential than the portion where the developer image was formed on the electrostatic latent image carrier after the transfer process, and based on the potential of the portion. return. Further, when a rubbing member provided so as to rub against the developer carrier is used as the voltage applying member, for example, a voltage having the same polarity as the developer acts on the developer in the seal portion. In addition, developer leakage is prevented.
In the developer layer thickness regulation section, a voltage having the same polarity as the normally charged developer acts on the oppositely charged or uncharged developer, so that the oppositely charged or uncharged developer passes. It is surely blocked. In addition, since the supply of the voltage to the paper dust removing means, the electricity removing means, and the rubbing member is performed by three kinds of charge trapping electrodes, the paper dust removing means, the electricity removing means, the layer thickness regulation or the sealing are performed in accordance with each. Voltage can be supplied.

According to a twenty-fifth aspect of the present invention, there is provided a process cartridge according to the twenty-third aspect.
In the above described process cartridge, the paper dust removing unit is grounded via a high resistance.

According to a twenty-fifth aspect of the present invention, since the paper dust removing means is grounded via a high resistance, the resistance value of the paper dust removing means is reduced, for example, in a high humidity environment. Even in this case, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. As a result, without damaging the electrostatic latent image carrier,
Image defects are reliably prevented.

According to a twenty-sixth aspect of the present invention, there is provided a process cartridge according to the twenty-second or twenty-third aspect.
In the above described process cartridge, the paper dust removing unit is electrically connected to a grid electrode of the charger via a high resistance.

According to the twenty-sixth aspect of the present invention, the paper dust removing means is electrically connected to the grid electrode of the charger through a high resistance. Even if the resistance value of the paper dust removing unit decreases, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. . As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Further, since the paper dust removing means and the grid electrode are electrically connected via the high resistance, the value of the voltage applied by the paper dust removing means is the voltage value of the grid electrode. The voltage value applied by the paper dust removing means becomes stable, for example, even in a high humidity environment.

According to a twenty-seventh aspect of the present invention, there is provided a process cartridge according to the twenty-second to twenty-second aspects of the present invention.
In the process cartridge according to any one of the above, the discharging means is a conductive film member having a resistance of 10 ² to 10 ⁸ Ωcm.

According to the process cartridge of the present invention, since the static elimination means is a conductive film member having a resistance of 10 ² to 10 ⁸ Ωcm, for example, the resistance value of the static elimination means decreases in an environment of high humidity. Even in this case, since a certain high resistance value is maintained, a large current does not flow from the charge eliminating unit to the electrostatic latent image carrier. As a result, without damaging the electrostatic latent image carrier,
Image defects are reliably prevented.

According to a twenty-eighth aspect of the present invention, there is provided a process cartridge according to the twenty-seventh aspect, wherein the static elimination means is arranged to elastically contact the electrostatic latent image carrier. It is characterized in that it also serves as a paper dust removing means.

According to a twenty-eighth aspect of the present invention, since the charge removing means also serves as a paper dust removing means arranged to elastically contact the electrostatic latent image carrier, the apparatus is enlarged and complicated. Without doing so, the surface of the electrostatic latent image carrier can be reliably discharged.

[0064]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a sectional view showing a schematic configuration of a laser beam printer 1 as an embodiment of the image forming apparatus of the present invention. In FIG. 1, a laser beam printer 1 is
A feeder unit for feeding paper (not shown) is provided at the bottom of the main body case 2. The feeder unit includes a sheet pressing plate 10 urged upward by a spring (not shown),
It includes a paper feed roller 11 and a friction separating member 14 pressed by the paper feed roller 11. The paper stacked on the paper pressing plate 10 is pushed up so as to contact the paper feed roller 11,
By rotating the paper feed roller 11 in the direction of the arrow in FIG. 1 at a predetermined timing, only the uppermost paper is separated and supplied between the paper feed roller 11 and the friction separating member 14.

A pair of registration rollers 12 and 1 are located on the downstream side in the sheet conveyance direction due to the rotation of the paper feed roller 11.
3 is rotatably supported, and conveys a sheet at a predetermined timing to a transfer position formed by a photosensitive drum 20 and a transfer roller 21, which will be described later.

The photosensitive drum 20 as a visible image carrier is
It is made of a positively chargeable material, for example, an organic photoreceptor mainly containing positively chargeable polycarbonate. More specifically, the photosensitive drum 20 has, for example, a cylindrical aluminum sleeve as a main body, and has a predetermined thickness (for example, about 20 μm) in which a photoconductive resin is dispersed in polycarbonate on an outer peripheral portion thereof.
m) is constituted by a hollow drum formed with a photoconductive layer, and is rotatably supported by the main body case 2 with the cylindrical sleeve grounded. Further, the photosensitive drum 20 is driven to rotate in a direction indicated by an arrow by driving means (not shown).

The charger 30 is, for example, a scorotron type charger for positive charging that generates corona discharge from a charging wire made of tungsten or the like. As shown in FIG. 2, which is an enlarged view showing the periphery of the charger 30 and the paper dust removing device 80 in FIG. 1, the charger 30 includes a corona wire 31 and a shield 32 that covers the corona wire 31.
And a grid electrode 33 provided so as to face the corona wire 31. In the present embodiment, in particular, the shield 32 and the grid electrode 33 are integrally formed. An opening B is provided in the holding portion 34 of the shield 32. A charge trapping electrode 90 is provided on the shield 32 so as to cover the opening B, and one end of the charge trapping electrode 90 is formed to extend to a paper dust removing device 80 described later.

With this configuration, the opening B
Is directly received by the ions discharged from the corona wire 31 and is charged.

The laser scanner unit 40 includes a laser generator (not shown) that generates a laser beam L for forming an electrostatic latent image on the photosensitive drum 20, and a polygon mirror (pentahedral mirror) 41 that is driven to rotate. , A pair of lenses 42 and 4
5 and reflection mirrors 43, 44 and 46.

In the developing device 50, a toner storage chamber 52 is formed in a case 51 as a developer chamber.
An agitator 53 is provided inside 2 so as to be rotatable around a rotation shaft 54. The toner stored in the toner storage chamber 52 is a positively chargeable non-magnetic one-component developer,
A particle size of 6 μm obtained by adding a well-known coloring agent such as carbon black and a charge controlling agent such as nigrosine, triphenylmethane and quaternary ammonium salt to a styrene-acrylic resin formed into a spherical shape by suspension polymerization. It has toner base particles having a particle size of 10 to 10 μm and an average particle size of 8 μm. The toner 55 is configured by adding silica as an external additive to the surface of the toner base particles.

The photosensitive drum 20 in the toner storage chamber 52
On the side, a developing chamber 55 for performing development by communicating with the toner storage chamber 52 through an opening A is formed, and a supply roller 56 and a developing roller 57 are rotatably pivotally supported. The toner on the developing roller 57 is regulated to a predetermined layer thickness by a layer-thickness regulating blade 58 provided with a contact portion made of silicone rubber at the tip of a thin plate-like elastic metal plate, and is used for development.

The transfer roller 21 is rotatably pivotally supported,
It is made of a conductive foamed elastic body made of silicone rubber or urethane rubber. The transfer roller 21 is configured to reliably transfer the toner image on the photosensitive drum 20 to the paper by the applied voltage.

The fixing unit 70 includes the registration roller 12
The heating roller 71 and the pressing roller 72 are provided on the further downstream side in the sheet conveyance direction from the sheet feeding roller 13 to the pressure contact portion between the photosensitive drum 20 and the transfer roller 21. The toner image transferred to the sheet is pressed while being heated and is fixed on the sheet.

A pair of transport rollers 73 for transporting the paper are provided downstream of the fixing unit 70 in the transport direction, and a pair of discharge rollers 7 are located downstream of the transport roller 73.
4 and a paper discharge tray 75 are provided in this order.

As shown in FIG. 2, the paper dust removing device 80 provided adjacent to the photosensitive drum 20 has a holder 83 and a base end supported on an upper portion of the holder 83. Urethane sheet 8 covered with non-woven fabric 81 at the tip
2, a brush-like member 86 for scraping paper dust, and a conductive plate 84 that supports the brush-like member 86 and is mounted on a holder 83.

As the non-woven fabric 81, a non-woven fabric integrated by confounding constituent fibers was used. This is because it is preferable to use a constituent fiber having a high degree of freedom in capturing fine paper powder between the fibers. As a constituent material, for example, polyester fiber, polyamide fiber, or the like is used.
The nonwoven fabric 81 is impregnated with an oil agent. Mineral oil, synthetic oil, etc. were used as the oil agent. The nonwoven fabric 81 was formed so as to have a length in the longitudinal direction substantially equal to the length in the longitudinal direction of the photosensitive drum 20, and was adhered to the front end portion of a urethane sheet 82 as a substrate made of a sheet-like member using a double-sided tape.

The urethane sheet 82 is a sheet member made of urethane rubber and has a hardness of 92 ° Hs (J
IS K-6301). Urethane sheet 8
2 is mounted at a position where the end of the urethane sheet 82 and the nonwoven fabric 81 reach a position where the photosensitive drum 20 is provided as shown by a dotted line in FIG.

The holder 83 is formed to have substantially the same length as the photosensitive drum 20 in the longitudinal direction of the photosensitive drum 20, and the photosensitive drum 20 is supported at both ends in the longitudinal direction by screws 91. Screwed to the frame.
Further, a paper powder storage chamber is formed inside the photosensitive drum 2.
An opening is formed on the side opposite to 0. Further, a urethane film 87 is attached to a lower portion of the holder 83. The base end of the urethane film 87 is attached to the holder 83 by using a double-sided tape, and the free end side is in contact with the photosensitive drum 20. By providing such a urethane film 87, it is possible to prevent paper powder from falling from the storage chamber of the holder 83.

As the brush-like member 86, a sheet on which fibers were planted was used. As shown in FIG. 2, this sheet is made of a plate 84 made of a conductive material such as aluminum.
It is provided above. Then, the plate 84 is attached on the holder 83, and the urethane sheet 82 is attached on the plate 84.

The end of the plate 84 and the end of the above-described charge trapping electrode 90 are screwed on the frame of the process cartridge with screws 85, and serve as the charge trapping electrode 90 and a voltage applying member. Plate 8
4 and the sheet of the brush-like member 86 are electrically connected. As described above, since the charge trapping electrode 90 is charged by directly receiving the ions discharged from the corona wire 31, the plate 84 and the brush-like member electrically connected to the charged charge trapping electrode 90. The sheet 86 will also be charged. That is, a voltage can be applied to the sheet of the brush-like member 86 without providing a dedicated power supply for the brush-like member 86.

(Operation Example) In the laser beam printer 1 of the present embodiment as described above, the surface of the photosensitive drum 20 is uniformly charged by the charger 30 and is modulated by the laser scanner unit 40 in accordance with image information. When L is irradiated, an electrostatic latent image is formed on the surface of the photosensitive drum 20. This electrostatic latent image is visualized with toner by the developing device 50, and the visible image formed on the photosensitive drum 20 is transported by the photosensitive drum 20 to a transfer position.
At the transfer position, the paper is supplied via the paper feed roller 11 and the registration rollers 12 and 13, and the visible image is transferred to the paper by a transfer bias applied by the transfer roller 21.

Next, the sheet is conveyed to the fixing unit 70, and is nipped and conveyed by the heating roller 71 and the pressing roller 72 of the fixing unit 70. The visible image on the sheet is pressed and heated to be fixed on the sheet. You. Then, the sheet is discharged to the discharge tray 75 above the laser beam printer 1 by the pair of transport rollers 73 and the discharge rollers 74, and the image forming operation is completed.

On the other hand, the toner remaining on the photosensitive drum 20 after the transfer is collected by the developing device 50 and used again for development. As described above, the laser beam printer 1 of the present embodiment
Employs a so-called cleaner-less development method.
Therefore, since a waste toner storage container for scraping and storing the toner remaining on the photosensitive drum 20 is not required, the size of the apparatus can be reduced, and the toner can be effectively used.

Paper dust adheres to the photosensitive drum 20 after the transfer. Of the paper dust, large fibrous paper dust is caught by the brush-like member 86, and small paper dust is removed by the nonwoven fabric 81. Removed. Particularly, in the present embodiment, the brush-like member 86 is charged by the charge trapping electrode 90 charged by the discharge from the corona wire 31 of the charger 30.
Since a voltage is applied to, an extremely high paper dust removing ability is exhibited. The paper dust is charged to a polarity opposite to that of the toner by a bias applied to the toner during transfer and having a polarity opposite to that of the toner. On the other hand, in the present embodiment, since the reversal development method is employed, the polarity of the voltage applied to the charger 30 is the same as the charge polarity of the toner. Therefore,
The polarity of the charge trapping electrode 90 charged by the discharge from the corona wire 31 and the polarity of the brush-like member 86 conducting to the charge trapping electrode 90 are also the same as the charge polarity of the toner, and the paper powder can be collected well. .

As described above, the image forming apparatus according to the present embodiment can apply an appropriate voltage to the brush-like member 86 without providing a dedicated power supply for the brush-like member 86, and thus the cost is reduced. Can be significantly reduced.

The charge trapping electrode 90 provided to face the corona wire 31 through the opening B basically rises to the voltage of the corona wire 31. However, the shield 32 covering the corona wire 31 of the scorotron charger 30
The voltage value can be controlled, though roughly, by adjusting the positional relationship between the two. Specifically, the shield 32
An opening may be provided, and the size of the opening and the distance from the opening to the charge trapping electrode 90 may be adjusted. In FIG. 2, the opening B of the holding portion 34 of the shield 32 is shown.
By extending the shield 32 to the position, the voltage of the charge trapping electrode 90 can be controlled to be low.

Further, regarding the current value, the charge trapping electrode 9
By adjusting the coverage of the corona wire 31 of 0, it is possible to roughly adjust the current value. Here, the coverage is defined as a charge trapping electrode viewed from the opening B with respect to the surface area of the cylinder when the corona wire 31 is considered as a cylinder, assuming that the discharge state from the corona wire 31 is uniform in all directions. 90 means the area ratio. For example, if the corona wire 31 is controlled at a constant current of 300 μA and the coverage of the corona wire 31 is 1/300,
A current of about 1 μA can flow through the charge trapping electrode 90. Here, the length of the corona wire 31 is 230 mm,
The distance between the corona wire 31 and the charge trapping electrode 90 is 5 m
m, the width of the opening B is 5 mm, and the width of the charge trapping electrode 90 is 5 mm.
mm, the area of the charge trapping electrode 90 seen from the opening B was 5 mm × 5 mm, that is, 25 mm 2. However, the above 1
The value μA is a value when the voltage control by the shield 32 is not performed. When such a voltage control is performed,
It is necessary to actually determine it experimentally.

Further, in the image forming apparatus of the present embodiment, since a scorotron charger having a positive polarity is used as the charger 30, the amount of ozone which adversely affects the environment can be significantly reduced.

In the above description, the brush-like member 86 of the paper dust removing device 80 has been described as an example of a member to which a voltage is applied by the charge trapping electrode 90, but the present invention is limited to such a structure. However, the thickness regulating blade 100 or the sealing member 10 as shown in FIG.
1 may be configured to apply a voltage. Charger 30
The polarity of the voltage applied to the layer thickness regulating blade 100 is generally the same as the charge polarity of the toner in the case of general reversal development. Alternatively, it is very convenient as a voltage supply source for the seal member 101.

In this embodiment, since the charge trapping electrode 90 and the brush member 86 to which a voltage is applied by the charge trapping electrode 90 are both provided inside the process cartridge, the power supply is omitted. In addition to this, there is an advantage that a power supply contact between the process cartridge and the image forming apparatus main body can be eliminated.

Further, both the charge trapping electrode 90 and a member to which a voltage is applied by the charge trapping electrode 90 may be provided in the image forming apparatus main body. Also in this case, there is an advantage that a power supply contact between the process cartridge and the image forming apparatus main body can be eliminated. For example, it is conceivable to apply a voltage to the fixing unit 70. By applying a voltage having the same polarity as the charging polarity of the toner to the fixing unit 70, electrostatic offset can be prevented. Further, a voltage may be applied to a paper dust removing unit (not shown) provided on the paper transport path. By applying a voltage having the same polarity as the charging polarity of the toner to such a paper dust removing unit, the paper dust can be satisfactorily removed. Further, a protective resistor may be connected in series between the charge trapping electrode 90 and the voltage applying member. 500M to limit the current value
Those having a resistance value of Ω or more can be suitably used.

The corona discharge electrode of the charger includes:
Needle-shaped electrodes, as well as wire electrodes as described above,
Alternatively, a saw-like electrode may be used.

Further, in the above embodiment, an example was described in which the voltage-applying member was a photosensitive member. However, the present invention is not limited to this. For example, an intermediate transfer member in a color image forming apparatus, The present invention is applicable even when paper or the like is used as the voltage applied member.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 4 is an enlarged view around the charger and the paper dust removing device in this embodiment. As shown in FIG. 4, in the present embodiment, the brush-like member 86 of the paper dust removing device 80 to which a voltage is applied by the charge trapping electrode 90 is grounded via the high resistance R1. different. In the present embodiment, as an example, 500 MΩ to 1 GΩ
Was used.

With such a configuration, when the resistance value of the brush-like member 86 decreases in a high-humidity environment or the like, the brush-like member 86 to which the voltage has been applied moves from the brush-like member 86 to the photosensitive drum 20. No large current flows,
The current will flow through the high resistance R1.

As a result, a large current does not cause a defect in the photosensitive drum 20, and the occurrence of an image defect due to the photosensitive drum-like defect can be reliably prevented.

As shown in FIG. 5, the high resistance R1
May be connected to the grid electrode 33 of the charger 30. With this configuration, it is possible not only to prevent generation of a large current from the brush-like member 86 to the photosensitive drum 20 as described above, but also to define the lower limit voltage of the voltage applied to the brush-like member 86 by the grid voltage. Therefore, the effect of stabilizing the voltage applied by the brush-like member 86 can be achieved even in a high humidity environment.

In the case of the grounding method in the case of FIG. 4, the ground terminal of the photosensitive drum 20 and the high resistance R1 may be electrically connected.

The configuration of the present embodiment can be realized not only in the above-described laser beam printer 1 but also in the laser beam printer 1.
It can also be realized by the process cartridge alone shown in FIG.

As described above, according to the present embodiment, the brush-like member 86 is grounded via a high resistance or grid-grounded. Occurrence can be reliably prevented.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description is omitted.

FIG. 6 is an enlarged view around the charger and the paper dust removing device in this embodiment. As shown in FIG. 6, in the present embodiment, the film for preventing the paper powder from falling from the storage chamber of the holder 83 and the static elimination film 200 as the static elimination means are also used. The difference between the first embodiment and the second embodiment is that a voltage is applied by the charge trapping electrode 91 for the charge removing film.

The static elimination film 200 includes stainless steel,
Metal such as aluminum, or urethane, acrylic,
A synthetic resin such as nylon can be used. When a synthetic resin is used, it is necessary to impart conductivity by performing a process of dispersing carbon on the surface. In the present embodiment, it is configured to have a resistance value of 10 ² Ωm to 10 ⁸ Ωm. Further, the charge removing film 200 is formed to extend in the longitudinal direction of the photosensitive drum 20 and is in uniform contact with the surface of the photosensitive drum 20.

Further, since it only has to function as the charge removing means, it need not be in the form of a film, but may be in the form of a brush or a roller.

The charge trapping electrode 91 for the charge removing film was provided separately from the charge trapping electrode 90 for the paper dust removing means. This is because the voltage for static elimination needs to be higher than the voltage applied for removing paper dust. Specifically, the charge trapping electrode is divided on the charger 31. Since the voltage value applied by the charge trapping electrode is determined by the area of the charge trapping electrode facing the charger 31, the facing area of the charge trapping electrode 91 for the static elimination film to the charger 31 is equal to that of the paper dust removing means. Is set so as to be larger than the charge trapping electrode 90. In the present embodiment, with such a configuration, the static elimination film 200 has a voltage of 800 V to 900 V.
V voltage is applied.

After the transfer step, the surface potential of the area where the toner image has been formed on the photosensitive drum 20 is 100 to 200 times higher than that of the area where the toner image has not been formed.
About V. Therefore, if charging is performed by the charger 31 in this state, the charging may be non-uniform. However, with the configuration as in the present embodiment, the photosensitive drum 2 is
Since the static elimination process is performed so as to make the non-uniformity of the potential on the surface of 0 almost uniform, subsequent charging by the charger 31 can be performed uniformly.

Further, since it is not necessary to provide a separate power supply for the static elimination film 200, it is possible to prevent an increase in size and cost of the apparatus.

Further, the resistance value of the static elimination film 200 is 1
0 ² Ωm to 10 ⁸ Ωm, so that the photosensitive drum 20
A large current does not flow to 0, and no defect is caused by the large current. As a result, the occurrence of image defects due to the photosensitive drum-like defects can be reliably prevented.

Note that the charge removing means is not necessarily a photosensitive drum 2
It is not necessary to contact with 0, and it suffices if they are arranged to face each other. However, as in the present embodiment, by using both the film for preventing paper powder from falling and the static elimination film, static elimination can be performed without increasing the size of the apparatus.

In this embodiment, as shown in FIG. 5, the ground end of the high resistance R1 may be connected to the grid electrode 33 of the charger 30. With this configuration, it is possible not only to prevent generation of a large current from the brush-like member 86 to the photosensitive drum 20 as described above, but also to define the lower limit voltage of the voltage applied to the brush-like member 86 by the grid voltage. Therefore, the effect of stabilizing the voltage applied by the brush-like member 86 can be achieved even in a high humidity environment.

Further, in the present embodiment, an example has been described in which the voltage is applied to the charge eliminating film together with the paper dust removing means by the charge trapping electrode. However, the voltage may be applied only to the charge eliminating film by the charge trapping electrode. good.

The configuration of the present embodiment can be realized not only in the above-described laser beam printer 1 but also in the laser beam printer 1.
It can also be realized by the process cartridge alone shown in FIG.

As described above, according to the present embodiment, the brush-like member 86 to which a voltage is applied by the charge trapping electrode 90 is grounded via a high resistance or grid ground, and the brush-like member 86 is also applied to the neutralization brush 200. Since the voltage is applied by the charge trapping electrode 91, it is possible to reliably prevent the generation of a large current from the brush-like member 86 to the photosensitive drum 20, obtain a good static elimination effect, and perform a uniform charging process. Is possible.

(Fourth Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the first to third embodiments are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, a voltage is applied to the brush-like member 86 by the charge trapping electrode 90, a voltage is applied to the charge eliminating film 200 by the charge trapping electrode 91, and a voltage is applied to the layer thickness regulating blade 100 by the charge trapping electrode 92. This is also an example in which a voltage is applied.

Since the effective voltage values for the regulation of the layer thickness, the removal of the paper dust, and the charge elimination are different from each other, in the present embodiment, the charge trapping electrode is further divided to form the charge trapping electrode 92 for regulating the layer thickness. Was provided.

With this configuration, the layer thickness can be satisfactorily regulated by the layer thickness regulating blade 100 charged to the same polarity as the developer. In addition, as described above, the paper dust can be satisfactorily removed while preventing the generation of a large current, and the elimination process using the elimination film can be satisfactorily performed. In addition, since it is not necessary to separately provide a power supply used for these, it is possible to reliably prevent the apparatus from increasing in size and cost.

Further, a voltage may be applied to the seal member 101 by the charge trapping electrode, or a voltage may be applied to the brush-like member 96, the charge eliminating film 200, and the seal member 101 by the charge trapping electrode. You may do it.

The present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0123]

According to the image forming apparatus of the first aspect,
In addition to the electrodes constituting the charger, a charge trapping electrode facing the corona discharge electrode is provided, and a voltage applying member that contributes to image formation at a predetermined potential is electrically connected to the charge trapping electrode. An appropriate voltage can be applied to the voltage-applied member without providing a power supply dedicated to the applying member. As a result, the cost of the image forming apparatus can be significantly reduced.

According to the image forming apparatus of the present invention, since the corona discharge device using the corona discharge wire for the corona discharge electrode or the scorotron charger is used as the charger, the corona discharge wire can favorably charge the charge trapping electrode. And an appropriate voltage can be applied to the voltage applying member electrically connected to the charge trapping electrode.

According to the image forming apparatus of the present invention, since the polarity of the voltage applied to the charger is set to be positive, the voltage-applying member is charged to the opposite polarity to the developer during transfer. Suitable as a member for removing paper dust, a seal member for preventing developer leakage, or a developer layer thickness regulating member for preventing the passage of reversely charged or uncharged developer in an image forming apparatus. Can be used. Also, the charging by the positive polarity corona discharge has an advantage that the amount of generated ozone is significantly smaller than the charging by the negative polarity corona discharge.

According to the image forming apparatus of the present invention, the charge trapping electrode and the voltage applying member are provided in the process cartridge detachable from the image forming apparatus. There is no need to provide a contact electrode for applying a voltage to the voltage-applied member, and it is possible to reduce costs and to prevent poor contact, so that good image formation can be performed over a long period of time. it can.

According to the image forming apparatus of the present invention, since the voltage-applying member is used as a paper dust removing means arranged opposite to the electrostatic latent image carrier, it is charged to a polarity opposite to that of the developer during transfer. Paper dust can be reliably removed from the electrostatic latent image carrier.

According to the image forming apparatus of the present invention, since the paper dust removing means is grounded via the high resistance, for example, when the resistance value of the paper dust removing means drops in a high humidity environment. Even in this case, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current can flow through the high resistance. As a result, image defects can be reliably prevented without damaging the electrostatic latent image carrier.

According to the image forming apparatus of the present invention, the paper dust removing means is electrically connected to the grid electrode of the charger through a high resistance. Even when the resistance value of the dust removing unit is reduced, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current can flow through the high resistance. As a result, image defects can be reliably prevented without damaging the electrostatic latent image carrier. Also, since the paper dust removing means and the grid electrode are electrically connected via the high resistance,
The value of the voltage applied by the paper dust removing means is defined by the voltage value of the grid electrode, and for example, the voltage applied by the paper dust removing means is stable even in a high humidity environment. Can be done.

According to the image forming apparatus of the present invention, the voltage-applying member is maintained at a predetermined potential relationship with the electrostatic latent image carrier with respect to the developer carrier carrying the developer. Since it is used as a member provided to be rubbed, a voltage having the same polarity as that of the developer acts on the developer in, for example, the seal portion, so that leakage of the developer can be reliably prevented. In the developer layer thickness regulating section, a voltage having the same polarity as the normally charged developer acts on the oppositely charged or uncharged developer, thereby preventing the passage of the oppositely charged or uncharged developer. It is possible to perform the developing operation satisfactorily by reliably stopping the operation.

According to the ninth aspect of the present invention, in addition to the electrodes constituting the scorotron charger, a charge capturing electrode facing the corona discharge wire is provided, and the voltage-applying member that contributes to image formation at a predetermined potential is provided. Since the battery is electrically connected to the charge trapping electrode, an appropriate voltage can be applied to the voltage-applying member without providing a power supply dedicated to the voltage-applying member. As a result, the cost of the process cartridge can be significantly reduced. In addition, there is no need to provide a contact electrode for applying a voltage to the voltage-applied member between the process cartridge and the image forming apparatus, so that cost can be reduced and a contact failure cannot occur. Good image formation can be performed over a period.

According to the tenth aspect of the present invention, since the polarity of the voltage applied to the charger is positive, the voltage-applying member is charged to a polarity opposite to that of the developer during transfer. Suitable for use in a wide range of process cartridges as a member for removing paper dust, a sealing member for preventing leakage of developer, or a developer layer thickness regulating member for preventing passage of reverse-polarized or uncharged developer. be able to.

According to the process cartridge of the present invention, since the voltage-applying member is a paper dust removing means arranged opposite to the electrostatic latent image carrier, it is charged to a polarity opposite to that of the developer during transfer. Paper dust can be reliably removed from the electrostatic latent image carrier.

According to the twelfth aspect of the present invention, since the paper dust removing means is grounded via a high resistance, the resistance value of the paper dust removing means may be reduced in a high humidity environment. Even if a large current does not flow from the paper dust removing means to the electrostatic latent image carrier,
The current can flow through the high resistance. as a result,
Image defects can be reliably prevented without damaging the electrostatic latent image carrier.

According to a thirteenth aspect of the present invention, the paper dust removing means is electrically connected to the grid electrode of the charger through a high resistance. Even when the resistance value of the paper dust removing unit decreases, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current can flow through the high resistance. . As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Further, since the paper dust removing means and the grid electrode are electrically connected via the high resistance, the value of the voltage applied by the paper dust removing means is the voltage value of the grid electrode. Thus, for example, even in a high humidity environment, the voltage value applied by the paper dust removing means can be stabilized.

According to a fourteenth aspect of the present invention, the voltage-applying member is slid with respect to the developer carrying member which holds the developer while maintaining a predetermined potential relationship with the electrostatic latent image carrying member. Since the member is provided so as to be rubbed, a voltage having the same polarity as that of the developer acts on the developer in the seal portion, for example, so that leakage of the developer can be reliably prevented. In the developer layer thickness regulating section, a voltage having the same polarity as the normally charged developer acts on the oppositely charged or uncharged developer, thereby preventing the passage of the oppositely charged or uncharged developer. It can be reliably prevented.

According to the image forming apparatus of the present invention,
Since the static eliminator arranged opposite to the electrostatic latent image carrier was used as the voltage applying member, the image after transfer was transferred to the static eliminator, which is a rubbing portion between the static eliminator and the electrostatic latent image carrier. It is possible to perform a static elimination action for eliminating unevenness of the surface potential between the portion and the non-image portion. Further, since there is no need to provide a dedicated power supply, cost can be reduced.

According to the image forming apparatus of the sixteenth aspect,
By the paper dust removing means as a voltage applied member, paper dust charged to a polarity opposite to that of the developer can be reliably removed from the electrostatic latent image carrier, and by the charge removing means as a voltage applied member, In the static elimination section, which is a rubbing section with the latent electrostatic image carrier, it is possible to perform a static elimination action for eliminating unevenness in surface potential between the image portion and the non-image portion after transfer. Further, since the supply of the voltage to the paper dust removing means and the electricity removing means is performed by two kinds of charge trapping electrodes, a voltage of a value corresponding to each of the paper dust removing and the electricity removing is provided by a dedicated power supply. Can be supplied without cost, and cost reduction can be achieved.

According to the image forming apparatus of the seventeenth aspect,
By the paper dust removing means as a voltage applied member, paper dust charged to a polarity opposite to that of the developer can be reliably removed from the electrostatic latent image carrier, and by the charge removing means as a voltage applied member, In the static elimination section, which is a rubbing section with the electrostatic latent image carrier, it is possible to perform a static elimination action so as to eliminate unevenness of the surface potential in the image area and the non-image area after transfer, and Since the rubbing member provided so as to rub against the body is used as the voltage applying member, for example, a voltage having the same polarity as the developer acts on the developer in the seal portion,
Developer leakage can be prevented, and in the developer layer thickness regulation section,
A voltage having the same polarity as that of the normally charged developer acts on the oppositely charged or uncharged developer, so that the passage of the oppositely charged or uncharged developer can be reliably prevented. Further, since the supply of the voltage to the paper dust removing unit, the charge removing unit, and the rubbing member is performed by three types of charge trapping electrodes, a voltage having a value corresponding to each of the paper dust removal and the charge removal,
The power can be supplied without providing a dedicated power supply, and cost can be reduced.

According to the image forming apparatus of the eighteenth aspect,
Since the paper dust removing unit is grounded via a high resistance, for example, in a high humidity environment, even when the resistance value of the paper dust removing unit decreases, the paper dust removing unit may No large current flows to the electrostatic latent image carrier,
The current will flow through the high resistance. as a result,
Image defects can be reliably prevented without damaging the electrostatic latent image carrier.

According to the image forming apparatus of the nineteenth aspect,
Since the paper dust removing unit is electrically connected to the grid electrode of the charger via a high resistance, for example, when the resistance value of the paper dust removing unit is reduced in a high humidity environment. However, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Also, since the paper dust removing means and the grid electrode are electrically connected via the high resistance,
The value of the voltage applied by the paper dust removing means is defined by the voltage value of the grid electrode. For example, even in a high humidity environment, the voltage applied by the paper dust removing means is stable. Can be done.

According to the image forming apparatus of the twentieth aspect,
Since the static eliminator is a conductive film member having a resistance of 10 ² to 10 ⁸ Ωcm, for example, in a high-humidity environment, even when the resistance of the static eliminator decreases, a certain high resistance is maintained. A large current does not flow from the charge removing unit to the electrostatic latent image carrier. As a result, image defects can be reliably prevented without damaging the electrostatic latent image carrier.

According to the image forming apparatus of the twenty-first aspect,
The static elimination means also serves as a paper dust removing means arranged to be in elastic contact with the electrostatic latent image carrier, so that the surface of the electrostatic latent image carrier can be reliably secured without increasing the size and complexity of the apparatus. Can be neutralized.

According to the process cartridge of the present invention, since the static elimination means arranged opposite to the electrostatic latent image carrier is used as the voltage applying member, the static elimination means and the electrostatic latent image carrier are not used. In the static elimination section, which is a rubbing section, a static elimination action can be performed so as to eliminate unevenness in surface potential between the image portion and the non-image portion after transfer. Further, since there is no need to provide a dedicated power supply, cost can be reduced.

According to the process cartridge of the twenty-third aspect, the paper dust removing means as a voltage-applied member is
Paper powder charged to the opposite polarity to the developer can be reliably removed from the electrostatic latent image carrier, and the charge removing means as a voltage applying member allows the paper to be rubbed with the electrostatic latent image carrier in a rubbing portion. In a certain static elimination section, a static elimination action can be performed so as to eliminate unevenness in surface potential between the image portion and the non-image portion after transfer. Further, since the supply of the voltage to the paper dust removing means and the electricity removing means is performed by two kinds of charge trapping electrodes, a voltage of a value corresponding to each of the paper dust removing and the electricity removing is provided by a dedicated power supply. Can be supplied without cost, and cost reduction can be achieved.

According to the process cartridge of the twenty-fourth aspect, the paper dust removing means as the voltage-applied member is
Paper powder charged to the opposite polarity to the developer can be reliably removed from the electrostatic latent image carrier, and the charge removing means as a voltage applying member allows the paper to be rubbed with the electrostatic latent image carrier in a rubbing portion. In a certain static elimination section, static elimination can be performed so as to eliminate unevenness in surface potential between the image portion and the non-image portion after transfer, and further, a slidable member provided so as to rub against the developer carrier. Since the rubbing member is used as the voltage-applying member, for example, a voltage having the same polarity as the developer acts on the developer in the seal portion, and the developer can be prevented from leaking. A voltage having the same polarity as that of the normally charged developer acts on the charged or uncharged developer, so that the passage of the oppositely charged or uncharged developer can be reliably prevented. Further, since the supply of the voltage to the paper dust removing means, the electricity removing means, and the rubbing member is performed by three kinds of charge trapping electrodes, a voltage having a value corresponding to each of the paper dust removing and the electricity removing is dedicated. Can be supplied without providing a power source, and cost reduction can be achieved.

According to the twenty-fifth aspect of the present invention, since the paper dust removing means is grounded via a high resistance, the resistance value of the paper dust removing means decreases in an environment of high humidity, for example. Even in this case, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. As a result, without damaging the electrostatic latent image carrier,
Image defects can be reliably prevented.

According to the twenty-sixth aspect of the present invention, the paper dust removing means is electrically connected to the grid electrode of the charger through a high resistance. Even if the resistance value of the paper dust removing unit decreases, a large current does not flow from the paper dust removing unit to the electrostatic latent image carrier, and the current flows to the high resistance. . As a result, the image defect is reliably prevented without damaging the electrostatic latent image carrier. Further, since the paper dust removing means and the grid electrode are electrically connected via the high resistance, the value of the voltage applied by the paper dust removing means is the voltage value of the grid electrode. The voltage value applied by the paper dust removing means can be stabilized, for example, even in a high humidity environment.

According to the process cartridge of the present invention, since the static elimination means is a conductive film member having a resistance of 10 ² to 10 ⁸ Ωcm, for example, the resistance value of the static elimination means decreases in a high humidity environment. Even in this case, a certain high resistance value can be maintained, and a large current does not flow from the charge eliminating unit to the electrostatic latent image carrier. As a result, image defects can be reliably prevented without damaging the electrostatic latent image carrier.

According to the process cartridge of the present invention, since the charge eliminating means also serves as a paper dust removing means arranged to be in elastic contact with the electrostatic latent image carrier, the apparatus is enlarged and complicated. Thus, the charge on the surface of the electrostatic latent image carrier can be reliably removed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view around a charger and a paper dust removing device in the image forming apparatus of FIG. 1;

FIG. 3 is an enlarged view of the vicinity of a charger, a paper dust removing device, and a developer carrier in the image forming apparatus of FIG. 1;

FIG. 4 is an enlarged view around a charger and a paper dust removing device of an image forming apparatus according to a second embodiment of the present invention (part 1).

FIG. 5 is an enlarged view around a charger and a paper dust removing device of an image forming apparatus according to a second embodiment of the present invention (part 2).

FIG. 6 is an enlarged view of the vicinity of a charger, a paper dust removing device, and a charge removing unit of an image forming apparatus according to a third embodiment of the present invention.

FIG. 7 is an enlarged view of the vicinity of a charger, a paper dust removing device, a charge removing unit, and a layer thickness regulating unit of an image forming apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser beam printer 20 Photosensitive drum 30 Charger 31 Corona discharge wire 32 Shield 33 Grid electrode 80 Paper dust removing device 81 Nonwoven fabric 82 Urethane sheet 84 Plate 86 Brush member 90 Charge trapping electrode 91 Charge trapping electrode 92 Charge trapping electrode 100 Layer thickness Regulator blade 101 Seal member 200 Static elimination film R1 High resistance

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H003 BB11 CC01 EE01 EE08 EE11 EE18 2H034 AA02 BD06 BD09 2H035 AA14 AA24 AB02 AZ03 2H071 BA04 BA13 BA20 BA27 DA06 DA15 DA34

Claims (28)

[Claims] 1. An image forming apparatus comprising: a charger having a corona discharge electrode; and a voltage-applying member which contributes to image formation at a predetermined potential, wherein the corona is provided in addition to an electrode constituting the charger. An image forming apparatus, comprising: a charge trapping electrode facing a discharge electrode, wherein the voltage receiving member and the charge trapping electrode are electrically connected. 2. The image forming apparatus according to claim 1, wherein the charger is a corotron charger or a scorotron charger using a corona discharge wire for the corona discharge electrode. 3. The image forming apparatus according to claim 1, wherein the polarity of the voltage applied to the charger is positive. 4. The image forming apparatus includes a charger having a corona discharge electrode, a voltage-applying member contributing to image formation at a predetermined potential in a process cartridge, and the process cartridge is detachably provided. The image forming apparatus, wherein the charge trapping electrode is provided so as to face the corona discharge electrode other than the electrode constituting the charger, and is electrically connected to the voltage applying member. 2. The device according to claim 1, wherein
4. The image forming apparatus according to any one of claims 1 to 3. 5. The image forming apparatus according to claim 1, wherein the voltage applying member is a paper dust removing unit arranged to face the electrostatic latent image carrier. 6. The image forming apparatus according to claim 5, wherein said paper dust removing unit is grounded via a high resistance. 7. The image forming apparatus according to claim 5, wherein the paper dust removing unit is electrically connected to a grid electrode of the charger via a high resistance. 8. A member provided such that the voltage-applying member maintains a predetermined potential relationship with the electrostatic latent image carrier and rubs against a developer carrier carrying a developer. The image forming apparatus according to claim 1, wherein: 9. A process cartridge comprising: a scorotron charger having a corona discharge wire; and a voltage-applying member that contributes to image formation at a predetermined potential, and is detachable from an image forming apparatus. A process cartridge, comprising: a charge trapping electrode facing the corona discharge wire, in addition to an electrode constituting a charger, wherein the voltage applying member and the charge trapping electrode are electrically connected. 10. The process cartridge according to claim 9, wherein the polarity of the voltage applied to the charger is positive. 11. The process cartridge according to claim 9, wherein said voltage-applied member is a paper dust removing unit arranged to face said electrostatic latent image carrier. 12. The process cartridge according to claim 11, wherein said paper dust removing means is grounded via a high resistance. 13. The process cartridge according to claim 11, wherein said paper dust removing means is electrically connected to a grid electrode of said charger via a high resistance. 14. A member provided to maintain a predetermined potential relationship with the electrostatic latent image carrier and to rub against a developer carrier carrying a developer, the voltage applying member being provided. The process cartridge according to claim 9, wherein: 15. The image forming apparatus according to claim 1, wherein the voltage applying member is a static eliminator arranged to face the electrostatic latent image carrier. 16. The voltage-applying member includes a paper dust removing unit arranged to face the electrostatic latent image carrier, and a charge removing unit arranged to face the electrostatic latent image carrier. The image forming apparatus according to any one of claims 1 to 4, wherein the trapping electrode includes two kinds of charge trapping electrodes for the paper dust removing unit and the charge removing unit. 17. The apparatus according to claim 17, wherein the voltage-applying member includes a paper dust removing unit arranged to face the electrostatic latent image carrier, a charge removing unit arranged to face the electrostatic latent image carrier, and the electrostatic latent image carrier. A rubbing member provided so as to rub against a developer carrier that holds a developer while maintaining a predetermined potential relationship with the image carrier; and as the charge trapping electrode, the paper dust removal. The image forming apparatus according to any one of claims 1 to 4, further comprising three types of charge trapping electrodes: one for a unit, one for the charge removing unit, and the rubbing member. 18. The paper dust removing means according to claim 16, wherein the paper dust removing means is grounded via a high resistance.
The image forming apparatus as described in the above. 19. The image forming apparatus according to claim 16, wherein the paper dust removing unit is electrically connected to a grid electrode of the charger via a high resistance. 20. The static elimination means having a resistance of 10 ² to 10 ^8.
The image forming apparatus according to any one of claims 15 to 19, wherein the image forming apparatus is a conductive film member of Ωcm. 21. An image forming apparatus according to claim 20, wherein said charge removing means also serves as a paper dust removing means arranged to elastically contact said electrostatic latent image carrier. 22. The process cartridge according to claim 9, wherein said voltage-applied member is a discharging unit arranged to face said electrostatic latent image carrier. 23. The voltage-applying member includes a paper dust removing unit arranged to face the electrostatic latent image carrier, and a charge removing unit arranged to face the electrostatic latent image carrier. 11. The process cartridge according to claim 9, wherein the trapping electrode includes two types of charge trapping electrodes for the paper dust removing unit and for the charge removing unit. 24. The voltage applying member, comprising: a paper dust removing unit arranged to face the electrostatic latent image carrier; a charge removing unit arranged to face the electrostatic latent image carrier; A rubbing member provided so as to rub against a developer carrier that holds a developer while maintaining a predetermined potential relationship with the image carrier; and as the charge trapping electrode, the paper dust removal. The process cartridge according to claim 9, further comprising three types of charge trapping electrodes for the device, the charge removing device, and the rubbing member. 25. The paper dust removing means according to claim 22, wherein the paper dust removing means is grounded via a high resistance.
The process cartridge as described. 26. The process cartridge according to claim 22, wherein the paper dust removing unit is electrically connected to a grid electrode of the charger via a high resistance. 27. The static elimination means having a resistance of 10 ² to 10 ^8.
The process cartridge according to any one of claims 22 to 26, wherein the process cartridge is a conductive film member of Ωcm. 28. The process cartridge according to claim 27, wherein said static elimination means also functions as a paper dust removing means arranged to elastically contact said electrostatic latent image carrier.