JP3013769B2 - Charging method, charging device, and image forming apparatus using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging method, a charging device, and an image forming apparatus using the same in an electrophotographic copying machine, a printer, and the like. The present invention relates to an inexpensive and high-performance charging method for charging a body through a minute gap, a charging device, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer using the above-described electrophotographic method, the surface of a charge receptor such as a photosensitive drum is uniformly charged by a charging device, and then the image light is charged. Is applied to form an electrostatic latent image on the surface of a photosensitive drum or the like, and the electrostatic latent image is developed with a developer to form an image. As a charging device used in such an image forming apparatus, a charging device using a corona discharge and a charging device using a contact charging method using a charging roll or the like are conventionally known.

[0003] Among these charging devices, a charging device utilizing corona discharge has a discharge wire stretched in a shield case so as to be close to the surface of a photosensitive drum, and a high voltage is applied to the discharge wire to cause a corona discharge. By causing a discharge, a charge of a predetermined polarity is applied to the surface of the photoreceptor drum to charge it to a predetermined potential. Although a charging device using such a corona discharge has excellent charging uniformity, a large amount of discharge products such as ozone and nitrogen oxides are generated with the corona discharge, so that a treatment is required. As a result, there has been a problem that the size and cost of the image forming apparatus are likely to be increased.

For this reason, recently, a so-called contact charging type charging device for charging a photosensitive drum by directly contacting a charging electrode with the photosensitive drum has been proposed and widely used. In such a charging device, a conductive member such as an elastic roll or a brush is arranged to be in contact with the surface of the photosensitive drum, and a DC voltage or a voltage obtained by superimposing a DC voltage and an AC voltage is applied to these conductive members. When the voltage is applied, charging is performed at a contact portion between the conductive member and the photosensitive drum. In addition, Japanese Patent Application Laid-Open Nos.
As disclosed in JP-A-282279 or the like, an apparatus having a blade-shaped charging electrode pressed against the surface of a photosensitive drum has already been proposed. In such a charging device, the amount of ozone generated is extremely small because corona discharge is not used, and the conductive member may be arranged so as to be in contact with the photosensitive drum. It has the advantage that it is suitable for conversion.

However, among the above-mentioned contact type charging devices, a charging device using a roll-shaped conductive member requires a support device for rotatably supporting the charging roll, and the like.
There is a problem that the structure of the charging device is complicated. In addition, in order to perform uniform charging in the charging device using the roll-shaped conductive member, it is necessary to improve the adhesion between the elastic roll and the photosensitive drum to form a stable minute gap. It is necessary to take measures such as lowering the hardness of the rubber forming the roll. Therefore, means for impregnating the elastic roll with a large amount of process oil is required, and there is a problem that the process oil easily transfers to the photosensitive drum and adversely affects the image quality. On the other hand, in order to solve such a problem, there is a method of improving the outer shape accuracy of the elastic roll. However, it is very difficult to improve the outer shape accuracy of the elastic body such as rubber, and it is difficult to improve the outer shape accuracy of the manufactured elastic roll. The problem of lowering the yield and increasing the cost is newly introduced.

In the case of a charging device using the above-mentioned roll-shaped conductive member, the elastic roll is brought into contact with the photoreceptor at a certain pressure. , Causing uneven charging. For this reason, a charging device using a roll-shaped conductive member is not suitable for a large and high-speed image forming apparatus. Further, it is desirable to apply an oscillating voltage in order to maintain uniform charging over a long period of time in the above-mentioned established contact type charging device. As a problem of such a contact type charging device of the oscillating voltage application type, generation of “charging noise” caused by an AC component of a charging bias applied to a contact charging member is given.

[0007] The "charging sound" peculiar to the contact type charging device for applying the oscillating voltage is an electrostatic attraction force generated between the photosensitive member and the contact charging member due to the AC component of the applied charging bias. Is considered to be generated by vibrating the charging member and repeatedly hitting the photoconductor. In contact-type charging devices using elastic rolls, measures have been taken, such as putting a weight on the photoconductor drum and making the base material of the photoconductor drum thicker than required in terms of strength. The cost has gone up.

[0008] In order to reduce the charging noise, it is effective to reduce the weight of the contact charging member, and a system using a film for the contact charging member has already been proposed.

On the other hand, in the case of a charging device using a brush-shaped conductive member, although it is effective for uniform contact as compared with the above-mentioned roll-shaped member, a brush sweep appears on an image as charging unevenness. There is a problem that it is easy.

Further, in the case of a charging device using a blade-shaped charging electrode, there is a problem that it is difficult to set minute voids required for discharging, and it is difficult to perform uniform and good charging. Furthermore, in the case of a charging device that uses a blade-shaped charging electrode and the blade-shaped charging electrode also serves as a cleaning blade, it is necessary to set a large contact pressure to a charge receptor such as a photosensitive drum.
Another problem is that the load on the photosensitive drum increases.

In order to avoid the above problem, a charging device disclosed in Japanese Patent Application Laid-Open No. 4-249270 has already been proposed. As shown in FIG. 34, this charging device includes a flexible film-shaped member 1 as a conductive member.
02, the free end 102a of the film-shaped member 102
Is arranged to contact the surface of the photoconductor 101. Then, by applying a DC voltage from the power source 103 to the film member 102 via the mounting substrate 103, a discharge is caused in the minute gap A and the surface of the photoconductor 101 is charged to a predetermined potential. It is.

The charging device shown in FIG. 34 has an advantage that stable contact can be easily obtained with a simple structure, and the cost of the member itself is lower than other conductive members.

However, in such a charging device using a flexible film-like member as the conductive member, since the film-like member 102 is arranged in a fixed state, ozone and the like generated at the time of discharge are generated. Have a problem that the discharge products adhere to the surface of the film-like member 102 to prevent normal electrification and generate streak-like image defects. This is because the film member 102 and the photoconductor 10
The discharge product generated in the minute gap A loses its place to go, and is generated because it adheres to the surface of the film-like member 102. This discharge product, when the film-shaped member 102 is fixed, unless provided with an external cleaning means, etc.
Difficult to clean.

To avoid this problem, a method in which a tubular film is rotated and used is also disclosed in Japanese Patent Laid-Open No. 4-23.
It has already been proposed as shown in JP-A-2977. Japanese Patent Application Laid-Open No. 4-232977 discloses a configuration in which a roller that is driven to rotate is inserted into a film, and the film is brought into contact with a photosensitive member by a guide member. According to such a configuration, it is described that charging is performed by a slack portion of the film contacting the photoconductor, and stable charging is performed by softly and widely contacting the surface of the photoconductor.

[0015]

However, the above-mentioned prior art has the following problems. That is, in the case of the charging device proposed in Japanese Patent Application Laid-Open No. Hei 4-232977, a driving mechanism for driving the roller to rotate is required, and the roller directly changes the shape of the portion where the film contacts the photoconductor. Since it cannot be regulated, the contact state between the roller and the photoreceptor becomes unstable, and there is a problem that stable charging cannot be performed when the mechanical characteristics of the film change due to the environment or the like.

Further, in a configuration in which the film is pressed against the rotary drive roll from the outside by a fixed guide member as in this technique, it is necessary to press the film with a surface in order to transmit a driving force to the film. However, if a guide member for holding the film on the surface is provided, the frictional resistance of the guide member increases due to adhesion of a discharge product or a developer in a long-term use, and the rotation of the film is hindered. Slip occurs. If the film is rotating at approximately the same speed as the photoreceptor, the part of the film that started vibrating due to electrostatic adsorption at the contact with the photoreceptor will separate from the photoreceptor immediately, so hit the photoreceptor. There is no. However, when the film slips, the film in a vibrating state repeatedly hits the photoconductor, and noise is generated. It has been confirmed that the noise level increases as the amount of film slip increases, and that the noise level becomes maximum when the film is stopped. The noise level generated by the slightly slipped film is considerably smaller than the noise level generated when the elastic roll having the same width hits the photoreceptor, but it cannot be ignored when the charging width is increased.

Therefore, as a technique for obtaining a stable contact state between the roller and the photoreceptor or for reliably rotating the film at a constant speed with the photoreceptor, Japanese Patent Laid-Open Publication No.
Contact type charging devices such as those disclosed in Japanese Patent No. 2869 and Japanese Patent Application Laid-Open No. 5-273844 have already been proposed. Japanese Patent Application Laid-Open No. 5-72869 proposes a method in which a rotating roller is included in a film, and the film is brought into direct contact with a photosensitive member by the rotating roller. In this contact-type charging device, the film and the photoreceptor come into contact with a stable predetermined contact pressure, charging is performed at a contact portion with the photoreceptor, and both sides of an area having the charging function are contacted with a small contact pressure. That has the function of correcting uneven charging of the photoconductor by the area contacted by the minute contact pressure, and that stable charging is performed by increasing the area of the contact portion with the photoconductor. Is described.

In Japanese Patent Application Laid-Open No. Hei 5-273844, a charging portion that comes into contact with a member to be charged, a support portion that supports the charging portion, an elastic layer, and a support member that supports the elastic layer. And a supporting portion comprising: a charging member that can be brought into contact with the member to be charged in order to charge the member to be charged, wherein the charging portion and the supporting portion are contactable and separable; The object of the present invention is to provide a charging member which is configured to be larger than the outer diameter of the support portion to reduce the generation of charging noise and to prevent uneven charging or the like.

However, even in these systems,
A drive mechanism for rotating and driving the roller is required, and the roller needs to be elastic, which causes a problem of increasing the cost. Also, when this roller is fixed, the film cannot be driven smoothly and the film cannot be rotated, or the film is moved to one side in the width direction due to a thrust force acting on the film, and the end is damaged, There is a problem that image defects occur. Further, since the charging device according to Japanese Patent Application Laid-Open No. 5-72869 performs charging at a contact portion between a film and a photoreceptor, in order to perform stable charging, the charging device is provided on both sides of a region having a charging function. It is necessary to form a wide contact area with a small contact pressure, and it is difficult to set parameters. Also, the larger the contact area between the film and the photoreceptor, the more
If a DC voltage with an AC voltage superimposed is used as the power supply, a large amount of AC current unrelated to the charging of the photoconductor will flow, and the power supply capacity must be increased, increasing the cost of the power supply Leads to.

In these methods, when the contact pressure becomes non-uniform in the axial direction due to an error in the outer diameter of the rotating roller or a variation in the pressing spring, the film is moved to one side and the end is damaged. Then, an image defect is generated. In addition, the film sandwiched between the conductive elastic roller and the photoconductor has a large thrust force, the film is moved to one side, and the contained elastic roller contacts the photoconductor, causing leakage to the photoconductor and adversely affecting the image quality There is a problem that Even if this problem is avoided by error management, the cost increases as described above because the conductive elastic roller is used. Furthermore, there is a problem that charging is poor due to deterioration of the elastic material over time.

In addition, the film sandwiched between the elastic roller and the image carrier such as a photoreceptor always receives a deforming force.
If the film is left unoperated for a long time, the cross-sectional shape of the film undergoes permanent deformation. When charging is performed by rotating the elastic roller and the film in this state, the charging area is not constant due to fluctuations in the nip form during rotation, the convergence of the charging potential is not obtained, and density unevenness defects in printing such as halftone. There is also a problem that it appears in image quality.

An attempt was made to solve the above problem by selecting a film material having a small permanent deformation (small creep characteristic, which is a viscoelastic characteristic of a polymer material). For example, in order of material characteristics, in order of creep characteristics, polycarbonate (PC) <polyvinylidene fluoride (PVDF) <nylon, a tube having a diameter of 10 mm made of polyvinylidene fluoride (PVDF) and nylon is prototyped. High humidity environment (temperature 48 ° C, humidity 85
%), The cross-sectional shape after storage for 48 hours was observed, and a permanent deformation test of the cross-sectional shape was performed. As a result, a result as shown in FIG. 65 was obtained. As is apparent from this figure, although the deformation amount of the nylon tube is slightly large, the polyvinylidene fluoride tube is also deformed, and from the viewpoint of preventing the occurrence of uneven charging due to the deformation generated in the tube. , No significant difference was seen.

As described above, when the film material is used as a charging device, considering that it is necessary to satisfy both the permanent deformation and the charging performance, it is only necessary to consider the film material and to perform the charging due to the deformation of the film. It can be said that it is difficult to improve the defect.

As shown in Japanese Patent Application Laid-Open No. 4-268584, a charging member is composed of a conductive member to which a voltage is applied, and a rotatable tubular resistance layer member which is fitted around the conductive member and is rotatable. A contact charging device configured to charge the charged body by bringing the conductive member into contact with the charged body via the resistance layer member externally fitted thereto has been proposed, In the contact charging device according to JP-A-4-268584, charging is performed at a contact portion between the tubular resistance layer member and the member to be charged, so that the film is moved to one side in the width direction and the end portion is Damaged,
It is difficult to generate image defects and set parameters, and has the same problems as in Japanese Patent Application Laid-Open No. 5-72869.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to charge a photosensitive member with a flexible member instead of charging at a contact portion. An object of the present invention is to provide a charging method, a charging device, and an image forming apparatus using the charging method, which have stable charging performance at low cost and are charged through a minute gap.

It is another object of the present invention to provide a charging method, a charging device, and an image forming apparatus using the same, which can reduce the generation of charging noise and can perform uniform charging. It is in.

[0027]

According to a first aspect of the present invention, there is provided a charging method for charging an electrostatic latent image carrier using a tubular flexible member as a charging electrode. the Jo of the flexible member, a plurality of <br/> without direct contact through the internal disposed and the tubular flexible member of the tubular flexible member to the electrostatic latent image bearing member The regulating member causes the tube to contact the surface of the electrostatic latent image carrier , and reduces the rotational force of only the electrostatic latent image carrier.
The tubular flexible member is transmitted to a tubular flexible member.
The flexible member and the electrostatic member to such an extent that the
By bringing the tubular flexible member into contact with the latent image carrier and electrostatically attracting the tubular flexible member to the surface of the electrostatic latent image carrier, the curvature of the tubular flexible member is reduced by the electrostatic latent. both brought close to the curvature of the image bearing member, which is constituted of an electrostatic latent image bearing member by the tubular flexible member to charge through the minute gap.

According to a second aspect of the present invention, there is provided a charging device for charging an electrostatic latent image carrier by using a tubular flexible member as a charging electrode. The tubular flexible member is brought into contact with the electrostatic latent image carrier without directly contacting the electrostatic latent image carrier through the tubular flexible member inside the flexible member
A plurality of regulating members are provided, and the tube-shaped flexible member is brought into contact with the surface of the electrostatic latent image carrier by the regulating member, and the rotational force of only the electrostatic latent image carrier is reduced.
The tube-shaped flexible member is transmitted to the tube-shaped flexible member.
Contact with the flexible member to such an extent that the flexible member can be driven to rotate.
The curvature of the tubular flexible member is reduced by contacting the electrostatic latent image carrier and electrostatically adsorbing the tubular flexible member to the surface of the electrostatic latent image carrier. both brought close to the curvature of the electrostatic latent image bearing member, which is constituted of an electrostatic latent image bearing member by the tubular flexible member to charge through the minute gap.

Further, in the image forming apparatus according to a third aspect of the present invention, the electrostatic latent image carrier, a tubular flexible member as a charging electrode, and a voltage applied to the tubular flexible member. In the image forming apparatus having voltage applying means for applying a voltage, the inside of the tubular flexible member is not directly in contact with the electrostatic latent image carrier through the tubular flexible member, and A plurality of regulating members are provided for bringing the tubular flexible member into contact with the electrostatic latent image carrier, and the tubular flexible member is placed on the surface of the electrostatic latent image carrier by the regulating member. Contact, and only the electrostatic latent image carrier
The rotation force is transmitted to the tubular flexible member to
The extent that the flexible tube member can be driven and rotated
The flexible member and the electrostatic latent image carrier are brought into contact with each other, and the tube-shaped flexible member is electrostatically attracted to the surface of the electrostatic latent image carrier, thereby obtaining the electrostatic latent image carrier. both brought close to the curvature of the tubular flexible member to a curvature of the electrostatic latent image bearing member, those
The tube-shaped flexible member charges the electrostatic latent image carrier through a minute gap.

Further, the charging device according to a fourth aspect of the present invention is the charging device according to the second aspect, wherein
The restricting member is formed of the tubular flexible member and an electrostatic latent image bearing member.
It is configured to be provided in the vicinity of a region where the holding body comes into contact or comes closest .

Further, in the charging device according to a fifth aspect of the present invention, in the charging device according to the third aspect, the restriction device is provided.
The member may be a tube-shaped flexible member and an electrostatic latent image carrier.
Are provided in the vicinity of the area where the contact or the closest approach is made.

According to a sixth aspect of the present invention, in the charging device according to the second aspect, power is supplied to the flexible member by a regulating member.

Further, according to a seventh aspect of the present invention, in the image forming apparatus according to the third aspect,
The power supply to the flexible member is configured to be performed by the regulating member.

Further, in the charging device according to an eighth aspect of the present invention, in the charging device according to the fourth aspect, the regulating member is configured such that the flexible member and the electrostatic latent image carrier come into contact with or come closest to each other. Electrostatic latent image carrier upstream in the area and the electrostatic latent image
The configuration is such that the shape of the flexible member is regulated both on the downstream side in the rotation direction of the carrier .

Further, in the image forming apparatus according to a ninth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the regulating member is configured such that the flexible member and the electrostatic latent image carrier are in contact with each other. With the electrostatic latent image carrier rotation direction upstream of the approaching area
The configuration is such that the shape of the flexible member is regulated both on the downstream side in the rotation direction of the electrostatic latent image carrier .

The charging device according to a tenth aspect of the present invention is the charging device according to the second aspect, wherein the surface of the regulating member is treated with a high-resistance thin film.

Further, an image forming apparatus according to an eleventh aspect of the present invention is the image forming apparatus according to the third aspect, wherein the surface of the regulating member is treated with a high-resistance thin film.

Further, in the charging device according to a twelfth aspect of the present invention, in the charging device according to the second aspect, a high resistance surface layer is provided on a surface of the flexible member in which the conductive agent is dispersed. It is configured to use a charging electrode.

According to a thirteenth aspect of the present invention, in the image forming apparatus according to the third aspect, a high resistance surface layer is provided on a surface of the flexible member in which the conductive agent is dispersed. It is configured to use a charged electrode.

According to the charging device of the present invention, a rotatable conductive tubular film is provided inside:
A plurality of regulating members that do not directly contact the electrostatic latent image carrier through the tubular film, and contact the tubular film with the electrostatic latent image carrier are provided, and the tubular film is The regulating member is brought into contact with the surface of the electrostatic latent image carrier, and the rotation of only the electrostatic latent image carrier is performed.
The force is transmitted to the tubular film and the tubular
To the extent that the film can be driven to rotate, the flexible member and
By bringing the tubular film into contact with the electrostatic latent image carrier and electrostatically attracting the tubular film to the surface of the electrostatic latent image carrier, the curvature of the tubular film is changed to the curvature of the electrostatic latent image carrier. to close the both the tubular film
By the charging device for charging through a minute gap to the latent electrostatic image bearing member, a biasing member which biases the regulating member to the electrostatic latent image bearing member, and the restricting member and the electrostatic latent image bearing member And a gap holding member for holding the gap.

According to a fifteenth aspect of the present invention, in the charging device of the fourteenth aspect, the gap holding member is provided on a film holding member that holds the tubular film and the regulating member. Things.

According to a sixteenth aspect of the present invention, in the charging device of the fourteenth aspect, the gap holding member is provided on a regulating member.

A charging device according to a seventeenth aspect of the present invention is the charging device according to the fourteenth aspect, wherein the gap holding member is provided on an electrostatic latent image carrier.
It is.

The charging device according to an eighteenth aspect of the present invention is the charging device according to the fourteenth aspect, wherein the urging member is integrated with a film holding member or a regulating member that holds the tubular film and the regulating member. Is provided.

A charging device according to a nineteenth aspect of the present invention is the charging device according to the fourteenth aspect, wherein a friction coefficient of a side surface of the gap holding member that contacts the tubular film is increased. is there.

In the charging device according to a twentieth aspect of the present invention, in the charging device according to the sixteenth aspect, the regulating member and the gap holding member are integrally formed, and the regulating member is rotatably disposed. It is configured as follows.

A charging device according to a twenty-first aspect of the present invention is the charging device according to the sixteenth aspect, wherein the regulating member is rotatably disposed.

The charging device according to a twenty-second aspect of the present invention is the charging device according to the fourth aspect, wherein the electrostatic latent image is provided.
The ratio of the peripheral speed of the rotating flexible member to the peripheral speed of the carrier is 0.9 or more.

The charging device according to a twenty-third aspect of the present invention is the charging device according to the fourth aspect, wherein the flexible portion is provided.
It is configured such that regions with a high friction coefficient are provided at both ends along the axial direction of the material .

According to a twenty-fourth aspect of the present invention, in the charging device according to the fourth aspect, the electrostatic latent image is provided.
The non-image area on the surface of the carrier is provided with an area having a higher coefficient of friction than the image forming area.

The charging device according to claim 25 of the present invention, in the charging device according to claim 4, of the contact portion for contacting a flexible member of the regulating member, at least an electrostatic
The contact area of the contact portion located on the upstream side in the moving direction of the latent image carrier is set to be small.

The charging device according to a twenty-sixth aspect of the present invention is the charging device according to the fourth aspect, wherein at least one of the contact portions of the regulating member that contacts the flexible member has a reduced contact resistance. This is configured to perform a process of causing Here, as a process performed to reduce contact resistance on at least one of the contact portions of the regulating member that comes into contact with the flexible member, for example, a process of contacting the flexible member of the regulating member At least one of the contact portions has been subjected to a surface treatment that reduces the coefficient of friction compared to the base material forming the contact portion. In addition to this, at least one of the contact portions has a lubricant. Or a process of providing a sheet having a smaller coefficient of friction than a base material forming the contact portion on at least one of the contact portions.

The charging device according to a twenty-seventh aspect of the present invention is the charging device according to the fourth aspect, wherein at least one of the contact portions of the flexible member that comes into contact with the regulating member has a reduced contact resistance. This is configured to perform a process of causing Here, as a process performed to reduce contact resistance on at least one of the contact portions of the flexible member that comes into contact with the regulating member, for example, the contacting with the regulating member of the flexible member is performed. On the surface, a surface layer having a smaller coefficient of friction than the contact surface of the regulating member is used.In addition to this, a lubricant is applied to the surface of the flexible member that contacts the regulating member, The surface of the flexible member that comes into contact with the regulating member may be subjected to a surface treatment having a smaller coefficient of friction than the contact surface of the regulating member.

The charging device according to a twenty-eighth aspect of the present invention is the charging device according to the fourth aspect, wherein air is blown out from at least one of the contact portions of the regulating member that come into contact with the flexible member. Thus, the frictional resistance is reduced.

A charging device according to a twenty-ninth aspect of the present invention is the charging device according to the fourth aspect, wherein a rolling contact member is provided on at least one of the contact portions of the regulating member that contact the flexible member. It is configured to be provided.

[0056]

[0057]

[0058]

The charging device according to claim 30 of the present invention includes a rotatable conductive tubular film inside:
A plurality of regulating members that do not directly contact the electrostatic latent image carrier through the tubular film, and contact the tubular film with the electrostatic latent image carrier are provided, and the tubular film is The regulating member is brought into contact with the surface of the electrostatic latent image carrier, and the rotation of only the electrostatic latent image carrier is performed.
The force is transmitted to the tubular film and the tubular
The tube-shaped foil is rotated enough to rotate the film.
The curvature of the tubular film is reduced by bringing the film and the electrostatic latent image carrier into contact with each other and electrostatically attracting the tube-shaped film to the surface of the electrostatic latent image carrier. both brought close to the curvature of the latent image bearing member, like the tube
In a charging device for charging an electrostatic latent image carrier with a film through a minute gap, a separating section in which a gap between the regulating member and the image carrier is set large is provided at both ends in the longitudinal direction of the regulating member. It is what was constituted.

[0060] The charging device according to claim 31 of the present invention, in the charging device according to claim 30, the distance between the inner end of the separation portion provided at both ends in the longitudinal direction of the regulating member, the The length is shorter than the length of the tubular film in the axial direction, and is longer than the width of the image area of the image carrier.

A charging device according to a thirty-second aspect of the present invention includes a rotatable conductive tubular film inside:
A plurality of regulating members that do not directly contact the electrostatic latent image carrier through the tubular film, and contact the tubular film with the electrostatic latent image carrier are provided, and the tubular film is The regulating member is brought into contact with the surface of the electrostatic latent image carrier, and the rotation of only the electrostatic latent image carrier is performed.
The force is transmitted to the tubular film and the tubular
The tube-shaped foil is rotated enough to rotate the film.
The curvature of the tubular film is reduced by bringing the film and the electrostatic latent image carrier into contact with each other and electrostatically attracting the tube-shaped film to the surface of the electrostatic latent image carrier. both brought close to the curvature of the latent image bearing member, like the tube
In a charging device that charges the electrostatic latent image carrier with a film through a minute gap, the regulation of the shape of the tubular film by the regulating member is performed in a state where the voltage application to the conductive tubular film is turned off. It is configured to provide a regulation release means for releasing.

According to a thirty-third aspect of the present invention, in the image forming apparatus, an electrostatic latent image carrier is provided inside a rotatable conductive tubular film via the tubular film. A plurality of regulating members that do not directly contact the body and contact the tubular film with the electrostatic latent image carrier; and dispose the tubular film on the surface of the electrostatic latent image carrier with the regulating member. It is brought into contact, the electrostatic
The rotational force of the latent image carrier alone is transmitted to the tubular film.
To the extent that the tubular film can be driven and rotated
The tubular film and the electrostatic latent image carrier are
When the curvature of the tubular film is brought close to the curvature of the electrostatic latent image carrier by contacting and electrostatically attracting the tubular film to the surface of the electrostatic latent image carrier.
Both, in the image forming apparatus having a charging means for charging the electrostatic latent image carrier through the minute gap by the tubular film , mounting the charging means to an image forming unit detachable to the image forming apparatus body, A regulation for releasing the regulation of the shape of the tubular film by the regulating member of the charging unit by removing the image forming unit from the image forming apparatus main body in a state where the voltage application to the conductive tubular film is turned off. It is configured to provide a release means.

According to a thirty-fourth aspect of the present invention, there is provided an image forming apparatus comprising: an electrostatic latent image carrier; and a rotatable conductive tubular film inside the electrostatic latent image carrier via the tubular film. A plurality of regulating members that do not directly contact the body and contact the tubular film with the electrostatic latent image carrier; and dispose the tubular film on the surface of the electrostatic latent image carrier with the regulating member. It is brought into contact, the electrostatic
The rotational force of the latent image carrier alone is transmitted to the tubular film.
To the extent that the tubular film can be driven and rotated
The tubular film and the electrostatic latent image carrier are
When the curvature of the tubular film approaches the curvature of the electrostatic latent image carrier by contacting and electrostatically attracting the tubular film to the surface of the electrostatic latent image carrier ,
Further, in an image forming apparatus having charging means for charging the electrostatic latent image carrier with the tubular film through a minute gap, when the image forming apparatus is not operating, the conductive tubular In a state in which the application of the voltage to the film is turned off, a regulation releasing means for releasing the regulation of the shape of the tubular film by the regulating member of the charging means is provided.

[0064]

The charging device according to the present invention includes, for example, a cylindrical film 0 acting as a charging electrode as shown in FIG.
1 and a rod 02 contained therein. Two rods 02 are provided in the vicinity of the electrostatic latent image carrier 03, and the film 01 is attached so as to be bridged therebetween. In this state, when the electrostatic latent image carrier 03 rotates and a voltage is applied to the film 01, the electrostatic latent image carrier 03
A mechanical friction force and an electrostatic attraction force generated by the elasticity of the film are generated between the image carriers 03, and the film 01
Rotates at almost the same speed as the film, and at the same time, the film 01 and the electrostatic latent image
Discharge is started in the minute gap of the carrier 03, and an electrostatic latent image is formed.
The carrier 03 is charged. Here, the shape of the film 01 is regulated by the two rods 02, and the curvature is
Because of the small size, a longer discharge time than normal roll charging can be obtained. Generally, discharge is performed to a minute gap of about 100 microns, so that the present invention having a long minute gap can obtain sufficient charging performance. Further, the film 01 has a smaller mass than the roll charging, and the electrostatic attraction force acts on the film, so that the film 01 is stably
Contact with the electrostatic latent image carrier 03 enables stable charging regardless of the length in the axial direction. In the roll charging, the electrostatic latent image carrier 03 is brought into contact with a certain pressure. If the length in the axial direction is too long, the central portion is separated from the electrostatic latent image carrier 03, causing charging unevenness. Furthermore, with regard to the adhesion of the discharge products generated by the fixed film, rotation is expected to increase the apparent surface area, clean the discharge products by the air flow , and clean the contact action with the electrostatic latent image carrier. As a result, the above-mentioned defects do not occur. According to the present invention, by making the minute gap longer, superior characteristics can be obtained at a lower cost than the conventional charging device.

In the charging device and the like according to the second and third aspects of the present invention, since the regulating member for making the curvature of the flexible member close to the curvature of the electrostatic latent image carrier is provided, the electrostatic latent image carrier is provided. The gap between the flexible member and the flexible member can be widened, and stable charging performance can be obtained.

In the charging device and the like according to the fourth and fifth aspects of the present invention, it is easy to set a minute gap between the electrostatic latent image carrier and the flexible member.

Further, the contents described in claims 6 and 7 of the present invention relate to a power supply method. That is, by supplying power through this rod, the distance between the contact surface of the electrostatic latent image carrier and the power supply position can be made sufficiently long. This is extremely effective when a defect occurs in the electrostatic latent image carrier and a current leaks. Since the resistance during this time is determined by the volume resistivity × length, it is effective to use a two-layer film having a sufficiently high surface resistance as a measure against the leakage.

Further, when AC + DC is applied as a power supply, noise caused by AC is regarded as a problem. However, according to the present invention, a film having an appropriate rigidity is selected and inserted between the rods. It is possible to reduce noise to an unacceptable level. Specifically, by using a PVDF film having a thickness of about 100 microns, the noise could be reduced below that of a roll charger.

Further, claims 10 to 13 of the present invention
By charging device or the like described, either the surface of the regulating member to a high resistance thin film process, providing the high-resistance surface layer conductive agent on the surface of the flexible member is dispersed in the same manner as described above, electrostatic Submarine
This is extremely effective when a defect occurs in the image carrier and a current leaks.

[0070]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 2 shows an embodiment of an image forming apparatus to which the charging device according to the present invention is applied.

In FIG. 2, reference numeral 1 denotes a photosensitive drum as a cylindrical electrostatic latent image carrier, and a primary charger as a charging device according to the present invention is provided around the photosensitive drum 1. 2, a developing unit 3, a transfer roll 4, and a cleaning device 5 are arranged. Of these image forming members, members other than the transfer roll 4 are integrally formed as an image forming unit 6. This image forming unit 6
Is detachable from the image forming apparatus main body 7, and the unit 6 is replaced when the contained toner is consumed.

After the photosensitive drum 1 is uniformly charged to a predetermined potential by the primary charger 2, the photosensitive drum 1 is irradiated with a semiconductor laser (not shown) and a laser beam 10 from a laser beam generator 9 containing a polygon rotating mirror 8. On the surface of the photosensitive drum 1, an electrostatic latent image corresponding to an image is formed at a predetermined position. The electrostatic latent image formed on the surface of the photosensitive drum 1 is developed by the developing device 3 to become a toner image. At this time, the laser beam 10 writes the image area, and the toner having the same polarity as the surface potential of the photoconductor drum 1 charged by the primary charger 2 is transferred to the photoconductor drum 1. Developed on the laser light irradiation part of

The developing device 3 includes at least a developing roll 3
a and a layer forming member 3b, and the inside of the developing device 3 is filled with a magnetic toner 3c. The magnetic toner 3c filled in the developing device 3 is attracted to the surface of the developing roll 3a by the magnetic force of the developing roll 3a, and is then regulated to a predetermined layer thickness by the layer forming member 3b, and required electric charge is formed. Is charged. The toner adsorbed on the surface of the developing roll 3a and frictionally charged to a predetermined thickness and a predetermined polarity moves to a developing position close to the surface of the photosensitive drum 1 with the rotation of the developing roll 3a. The electrostatic latent image formed on the surface of the photosensitive drum 1 is developed by a toner layer.

The toner image formed on the photosensitive drum 1 is transferred by transfer charging of the transfer roll 4 onto the transfer paper 13 conveyed from the paper supply cassette 11 by the registration roll 12 at a predetermined timing. After the transfer,
The transfer paper 13 to which the toner image has been transferred is conveyed to a fixing device 15 by a conveyance belt 14 and subjected to a fixing process.
Discharged outside the device. In the fixing device 15, the transfer paper 13 is inserted between the fixing roll 15a and the pressure roll 15b, and is fixed by heat and pressure.

After the completion of the transfer step, the residual toner on the photosensitive drum 1 is removed by the blade 5 of the cleaning device 5.
a), and prepares for the next image forming step. Then, in the case of continuously forming images, the charging process by the primary charger 2 is continued, and all the above-described processes are repeated to output a plurality of continuous prints.

Incidentally, the charging device according to this embodiment is
In a charging device using a flexible member as a charging electrode,
It is configured to provide a regulating member that makes the curvature of the flexible member approach the curvature of the photoconductor.

Next, the configuration of an embodiment of the charging device according to the present invention will be described. The charging device according to this embodiment is used as the primary charger 2.

That is, the charging device 2 according to this embodiment
As shown in FIG. 3, a cylindrical film 20 as a flexible member acting as a charging electrode, and a rod 21 as a regulating member contained in the cylindrical film 20,
21. As the cylindrical film 20, for example, a film made of a PVdF film having a thickness of 100 μm is used. By filling the PVdF film with carbon black, the volume resistivity is adjusted to, for example, 10 ⁷ Ωcm. Stuff is used,
The volume specific resistivity of this PVdF film is 10 ⁷ to 1
It is also possible to use a material adjusted to about ⁰⁹ Ωcm. Further, a high resistance coating may be provided on the surface of the cylindrical film 20 as necessary. Further, as the cylindrical film, for example, a film whose diameter is set to 10 mm or 12 mm is used. Further, as shown in FIGS. 4 to 7, two rods 21 are arranged close to the photosensitive drum 1 and one reinforcing rod is provided at a position away from the photosensitive drum 1. Rod 22
Is arranged. As these rods 21, 21, and 22, for example, rods made of stainless steel, aluminum, or the like are used, but rods made of another metal material or another material may be used. The diameters of the two regulating rods 21, 21 disposed close to the photosensitive drum 1 are appropriately set.
1 is set to be small, the reinforcing rod 22
It is desirable to increase the thickness of the restricting rods as appropriate to prevent deformation such as bending of the regulating rods 21 along the longitudinal direction.
Further, as shown in FIG. 6, the two regulating rods 21 and 21 arranged close to the photoconductor drum 1 are arranged such that the center of the two regulating rods 21 and 21 is
Are arranged so as to be orthogonal to the center line L. Further, the three rods 21, 21, 22 are fixedly attached to a disk-shaped support member 23 at both ends. In addition, the support member 23 includes the charging device 3 configured as described above and the center of the two regulating rods 21 with respect to the photosensitive drum 1 with respect to the center line L of the photosensitive drum 1. Orthogonal and two regulating rods 21, 2
A mounting member 25 having a function as an energizing terminal for energizing the two restricting rods 21 and 21 is provided so that a distance (nip amount) between the first and the photosensitive drum 1 is maintained constant. , Are provided integrally outside the tracking roll 24.

Then, as shown in FIG. 4, for example, a voltage 1500
~ 2000V, 400Hz frequency AC voltage,
A voltage obtained by superimposing a DC voltage of 350 V is a high-voltage AC power supply 2
6 and a DC power supply 27.

Here, the shape of the cylindrical film 20 is regulated by the two regulating rods 21, 21, as shown in FIG. 15. By changing the relative distance (nip amount) N between the straight line M passing through the surface and the surface of the photosensitive drum 1, the curvature before and after the position where the cylindrical film 20 contacts the surface of the photosensitive drum 1 is changed. Is set to be large.

In FIG. 6, reference numeral 28 denotes a spacer in which a plurality of regulating rods 21 and 21 and a reinforcing rod 22 are arranged along the longitudinal direction of the rod so as to maintain a predetermined interval. ing.

In the charging device according to this embodiment having the above structure, the photosensitive member is charged via the minute gap by the flexible member, instead of charging at the contact portion, as described below. Thus, a charging device having stable charging performance can be provided.

That is, in this embodiment, as shown in FIG.
A high voltage AC power supply 26 and a DC power supply 27 apply a voltage obtained by superimposing a DC voltage of −350 V on an AC voltage of 00 to 2000 V and a frequency of 400 Hz. Then, in this state, the photosensitive drum 1 rotates, and the cylindrical film 20 is rotated.
When a voltage is applied to the cylindrical film 20, an electrostatic attraction force is generated between the cylindrical film 20 and the photosensitive drum 1, and the cylindrical film 20
Rotates at substantially the same speed as the photosensitive drum 1, and at the same time, discharge is started in the small gap G between the cylindrical film 20 and the photosensitive drum 1, and the photosensitive drum 1 is charged. The voltage application to the cylindrical film 20 can be realized by providing a contact object from the outside.
It is also possible to apply a predetermined voltage through 1, 21.

Further, the cylindrical film 20 is formed as shown in FIG.
And as shown in FIG. 4, is in contact with the photosensitive drum 1 .
Since the portion is deformed along the surface of the photosensitive drum 1 and has a small curvature, a longer discharge distance and longer discharge time than a normal roll-shaped charging member can be obtained.
As described above, when the photosensitive drum 1 is charged through the minute gap G, the discharge is generally performed to the minute gap of about 0 <G ≦ 100 μm.
The charging device of the present embodiment, in which the minute gap between 0 and the photosensitive drum 1 can be made long, can obtain sufficient charging performance.

FIGS. 8 and 9 show a minute gap (discharge area).
10 and FIG. 11 show the relationship between the length of the minute gap and the charging performance. These figures show that the charging performance is improved as the length of the minute gap is increased, and that the shape of the cylindrical film 20 is restricted by using the flexibility of the cylindrical film to make the shape of the cylindrical film 20 close to the photosensitive drum 1. This indicates that stable charging performance can be obtained by regulating with the rods 21 and 21.
Here, the cycle 1-2 on the vertical axis in FIG. 10 refers to the charging potential of the photosensitive drum 1 in the first charging cycle and 2
It shows the difference from the charging potential of the photoconductor drum 1 in the second charging cycle. The smaller the value of this cycle 1-2, the better the charging performance.

The cylindrical film 20 has a significantly smaller mass than the charging member in the form of a roll, and since the electrostatic attraction acts on the cylindrical film 20, the photosensitive drum 1 can be stably maintained. The charging device 3 can be stably charged over a long distance along the axial direction of the charging device 3. On the other hand, when a roll-shaped charging member is used, it is necessary to contact both ends of the roll-shaped supporting member to the photosensitive drum with a strong pressure to some extent. Moves away from the drum, causing uneven charging. Further, regarding the adhesion of the discharge products generated in the fixed film, the apparent rotation of the cylindrical film 20 increases the apparent surface area, cleans the discharge products by the air flow, and cleans by contact with the photosensitive drum. Since the action can be expected, the above-mentioned defect due to the adhesion of the discharge product does not occur.

According to the charging device of this embodiment, a minute gap can be stably provided with a very simple structure, and excellent characteristics can be obtained at lower cost than a conventional charging device.

The withstand voltage characteristics of the tubular film 20 are as follows. That is, in the conventional method in which the charging member of the film is directly brought into contact with the photoreceptor, it is necessary to withstand a predetermined applied voltage only by the thickness of the film, and the voltage required for the film becomes severe. However, in the case of this embodiment, by supplying power to the cylindrical film 20 through the regulating rods 21, the distance between the contact surface of the photosensitive drum 1 and the power supply position can be made sufficiently long. This is extremely effective when a defect occurs in the surface layer of the photosensitive drum 1 and a current leaks. Since the resistance between the contact surface of the photosensitive drum and the power supply position is determined by the volume resistivity × length of the cylindrical film 20, even if the film 20 has a low volume resistivity, the resistance between the contact surface of the photosensitive drum 1 and the power supply is small. By setting the length to the position large, a sufficient effect on the leak can be obtained.

FIG. 12 shows how the resistance value via the cylindrical film changes when the value of the DC voltage applied to the cylindrical film is changed, from the contact surface of the photosensitive drum to the power supply position. Is measured by changing the distance.

As is apparent from FIG. 12, when the distance from the contact surface of the photosensitive drum 1 to the power supply position is set to be large, even when the value of the DC voltage applied to the cylindrical film 20 is considerably increased. It can be seen that the resistance value via the tubular film 20 hardly decreases, and a sufficient effect on leakage can be obtained.

However, even in this case, a minute streak may be generated due to an increase in the current flowing in the leaked part with respect to the other parts. As a countermeasure, a two-layer film having a sufficiently high surface resistance is taken as a countermeasure. Using is also effective against leaks.

That is, the above tubular film 20 is
As shown in FIG. 3, an inner layer 2 having a relatively low volume resistivity
0a and the outer layer 20b having a relatively high volume resistivity have a two-layer structure,
The currents supplied from the first and second layers 21 and 21 flow through the inner layer 20a having a relatively low volume resistivity to a position close to the photosensitive drum 1 without causing a large voltage effect. A current flows to a position close to the photosensitive drum 1 through the layer 20b having a high volume resistivity, so that even if a defect occurs in the surface layer of the photosensitive drum 1, a large leak current is prevented from flowing. can do.

Further, the same effect as described above can be obtained by applying a high-resistance coating (for example, alumite) to the regulating rods 21, 21. Further, by providing a high resistance coating on the power supply member side, the surface treatment of the base material of the photosensitive drum 1 becomes unnecessary, and the cost of the photosensitive drum 1 can be reduced. In addition, it is possible to use a material that is hardly subjected to a surface treatment on the base material of the photosensitive drum 1. That is, when a defect occurs in the surface layer of the photosensitive drum 1, a large leak current is prevented from flowing on the surface of the photosensitive drum 1 as shown in FIG. High resistance coating treatment 1b
However, such a surface treatment of the base material 1c of the photosensitive drum 1 is not required, so that the cost of the photosensitive drum 1 can be reduced, and
The base material 1c can be made of a material that is hardly subjected to surface treatment.

Next, in order to confirm the characteristics of the charging device configured as described above, the present inventors experimentally manufactured a device in which various parameters constituting the charging device were changed and measured the charging characteristics. Was done.

That is, in the charging device configured as described above, as shown in FIG.
The "width" which is the distance between the outside of the first and second 21 and the "radius" of the first and second regulating rods 21 and 21, and the two regulating rods 21 and 2
A charging device in which the distance between a straight line connecting the surfaces of No. 1 and the tangent line of the photosensitive drum, that is, the “nip amount” and the like were variously changed was prototyped. FIG. 16 schematically shows a case where the radius and the nip amount of the two regulating rods 21 are changed in the charging device.

FIGS. 17 and 18 show the "nip" which is the distance between the straight line connecting the surfaces of the two regulating rods and the tangent to the photosensitive drum in the charging device. Amount ”is fixed to −0.7 mm, and the relationship between the AC voltage value Vpp and the charging voltage value Vh when the“ width ”of the two regulating rods is changed, and the“ width ”and AC
The relationship with the current value is shown.

As is apparent from FIGS. 17 and 18, when the width of the two regulating rods is set to be large, both the charging voltage value Vh and the AC current value increase. This is presumably because the larger the "width" of the two regulating rods, the wider the area where the film 20 and the surface of the photosensitive drum 1 are close to each other to form a minute gap. However, the charging voltage value Vh is
AC whose "width" is 8mm and 10mm lower than 6mm
8mm and 10mm saturating with voltage
It turns out that there is almost no change. On the other hand, the AC current value increases sequentially in widths of 6 mm, 8 mm, and 10 mm, and it can be seen that the AC current value increases in 8 mm and 10 mm, although the rate of increase is small. Therefore, the AC current value is different between the widths of the two restriction rods of 8 mm and 10 mm, so that the width of 10 mm allows more charging current to flow and the charging time until charging to the predetermined potential is shorter. .

FIG. 19 shows that the "radius" of the regulating rod is 1.5 mm and the "nip amount" which is the distance between a straight line connecting the surfaces of the two regulating rods and the tangent line of the photosensitive drum is shown in FIG. It shows a relationship between the AC voltage value Vpp and the voltage value of the so-called cycle 1-2 when the width is fixed to −0.7 mm and the two restricting rods are changed.

As apparent from FIG. 19, when the AC voltage value Vpp is increased, the voltage values in cycles 1 and 2 are slightly reduced, but there is little correlation with the "width" of the two regulating rods. I think that the. Also in this case, it can be confirmed that the discharge area is widened by increasing the “width” to some extent, and the charging performance is improved.

FIGS. 20 and 21 show the above charging device.
The AC voltage value Vpp when the “radius” of the regulating rod is fixed at 1.5 mm, the “width” of the two regulating rods is fixed at 8 mm, and the “nip amount” of the two regulating rods is changed.
And a charging voltage value Vh, and a “width” and an AC current value, respectively.

As is apparent from FIGS. 20 and 21, when the "nip amount" of the two regulating rods is set to be larger and closer to the photosensitive drum, the AC current value gradually increases. It can be seen that the charging voltage value Vh hardly changes.

FIG. 22 shows that in the above charging device, the "radius" of the regulating rod is fixed at 1.5 mm, the "width" of the two regulating rods is fixed at 8 mm, and the "nip amount" of the two regulating rods is adjusted. Shows the relationship between the AC voltage value Vpp and the voltage values of the so-called cycles 1 and 2 in the case where is changed.

As apparent from FIG. 22, in the setting of this experiment, it is considered that there are optimum values for V1 and V2 around the nip amount of 0.5. Since it is considered that the small gap area is narrowed by making the nip amount too small, the optimal nip amount is determined by the elasticity of the film, the film thickness,
It is considered that it varies depending on the relationship of the diameter of the photoconductor. In addition, it was confirmed that an excessively large nip amount means that the contact area between the photosensitive member and the film was increased, that is, only the reactive current irrelevant to the charging performance was increased.

FIGS. 23 and 24 show the above charging device.
AC when the “width” of the two regulating rods is 8 mm, the “nip” of the two regulating rods is fixed at −0.8 mm, and the “radius” of the two regulating rods is changed Relationship between voltage value Vpp and charging voltage value Vh, "width" and AC
The relationship with the current value is shown.

As is clear from FIGS. 23 and 24, the AC current value gradually increases as the "radius" of the two regulating rods is smaller, but the charging voltage value Vh hardly changes. I understand.

FIG. 25 shows the charging device in which the "width" of the regulating rod is fixed at 8 mm, the "nip amount" of the two regulating rods is fixed at -0.8 mm, and the "radius" of the two regulating rods is fixed. Is changed, the relationship between the AC voltage value Vpp and the voltage values of so-called cycles 1 and 2 is shown.

As is apparent from FIG. 25, it is considered that the "radius" of the regulating rod also has an optimum value due to the elasticity of the film, the diameter of the photosensitive member, and the like.

FIG. 26 shows the change in the sound pressure of the vibration sound when the rigidity (thickness) of the tubular film is changed.

As is clear from FIG. 26, the sound pressure becomes lower as the rigidity (thickness) of the tubular film becomes larger.

FIGS. 27 and 28 are graphs showing the measurement results when the change in the discharge noise due to the difference in the thickness and the material of the cylindrical film is measured.

As is clear from these figures, it can be seen that the magnitude of the discharge noise slightly changes depending on the thickness and the material of the tubular film.

FIGS. 29 and 30 show the elastic deformation characteristics of the film forming the cylindrical film, respectively.

FIG. 31 is a graph showing the relationship between the time and the slip amount of the cylindrical film when the charging device is used continuously.

As is apparent from FIG. 31, the slip amount is larger when the nylon-based tubular film is used. This seems to be due to the difference in surface smoothness due to the difference in the material of the tubular film.

Embodiment 1-2 FIG. 32 shows an embodiment 1-2 of the present invention. The same parts as those of the above embodiment are denoted by the same reference numerals and described. In this embodiment, the shape of the regulating member is different from that of the above embodiment.

That is, in the embodiment 1-2, the regulating member is not constituted by two rods, but is constituted by one rod 40 having a substantially elliptical cross section. As shown in FIG. 32, a relief portion 40a is formed at the lower end of the regulating rod 40 so as to absorb deformation caused by the cylindrical film 20 coming into contact with the surface of the photosensitive drum 1. I have. The regulating member 40 may have a shape as shown in FIG.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

In the above embodiment, the case where the number of regulating members is one or two has been described, but it is needless to say that three or more regulating members may be used.

Embodiment 2-1 FIG. 35 shows an embodiment of the invention according to claim 14, in which the same parts as those in the embodiment according to claim 2 are indicated by the same reference numerals. Then, in this embodiment 2-1,
A biasing member for biasing a regulating member that brings the curvature of the flexible member closer to the curvature of the image carrier toward the image carrier, and a gap holding member for keeping a gap between the regulating member and the image carrier are provided. It is configured.

That is, in the third embodiment, the shaping member is not used as the restricting member, but the V-shaped deformed material 50 having a substantially thick cross section is used, and the end face of the tracking roll 24 is in contact with the cylindrical film 20. It is configured to be. The restricting member 50 made of an irregularly shaped member having a substantially V-shaped cross section is made of, for example, an extruded material of aluminum or a molded material of a conductive resin. 20 is formed in an arc shape in order to reduce friction with 20. This regulating member 50
The arc-shaped portion 50a is formed concentrically and with the same radius as the regulating rod 21 of the embodiment shown in FIG. 6, or is formed concentrically and smaller in radius than the rod 21. Further, as shown in FIGS. 36 and 37, both ends of the regulating member 50 are fixed to the columnar supporting member 23 also serving as the axis of the tracking roll 24.
A tracking roll 24 is attached to the outer periphery of the support member 23 directly or via a bearing (not shown). The tracking roll 24 is used for the cylindrical film 2.
0 in the thrust direction, and the cylindrical film 2
It also serves as an edge guide that holds the zero edge. The tracking roll 24 has a function as a gap holding member, and is formed of a material having excellent wear resistance and moldability, for example, polyacetal or the like. Furthermore, the film side end 24 of the tracking roll 24
The end 24b that contacts the photoconductor drum 1 with a resin is coated with a resin or subjected to a roughening process or the like in order to increase the friction coefficient if necessary, so that the cylindrical shape is formed with the rotation of the tracking roll 24. The film 20 also receives a driving force from the end portion, and rotates more smoothly, thereby preventing noise generated together with poor rotation. In this manner, the driving force is applied to the cylindrical film 20 by the film-side end portion 24a of the tracking roll 24, so that the cylindrical film 20 is kept at a constant speed or a peripheral speed of the photosensitive drum 1. By making the speed higher than the speed, the rotation of the cylindrical film 20 becomes smooth, and the generation of noise can be effectively prevented.

Further, as shown in FIG. 37, the support member 23 to which the regulating member 50 is attached
Are integrally formed, and the mounting member 25 is urged toward the photosensitive drum 1 by a coil spring 51 as an urging member.

The other constructions and operations are the same as those of the embodiment shown in FIG. 5 and the like, and a description thereof will be omitted.

Embodiment 2-2 FIG. 38 shows an embodiment of the invention according to claim 16, and the same parts as those in the embodiment shown in FIG. In the embodiment 2-2, the gap holding member is provided on the regulating member.

That is, in this embodiment, the regulating member 52
The shaft-shaped regulating member 52 is rotatably attached to a housing (not shown) of the image forming unit 6. Also,
A tracking roll 24 as a gap holding member is attached to an end of the shaft-shaped regulating member 52. The tracking roll 24 is formed integrally with a shaft-shaped regulating member 52 and is configured to be rotatable, so that the shaft-shaped regulating member 52 is exposed through the tracking roll 24 as shown in FIG. Body drum 1
, And can be transmitted to the cylindrical film 20. By doing so, the rotation of the cylindrical film 20 is more stable, and it is possible to prevent annoying noise such as a beat sound due to discharge. The tracking roll 24 is formed integrally with a shaft-shaped regulating member 52 using a conductive synthetic resin, and the surface in contact with the photosensitive drum 1 is insulated, or the tracking roll 24 made of synthetic resin or rubber is used. May be attached to a metal shaft-shaped restricting member 52.

In this case, by directly attaching the shaft-shaped regulating member 52 to the image forming unit 6,
Since the support member 23 and the attachment member 25 for holding the film as shown in FIG. 3 are not required, the configuration can be further simplified.

Embodiment 2-3 FIG. 40 shows an embodiment of the invention according to claim 17, in which the same parts as those in the embodiment shown in FIG. In the embodiment 2-3, instead of attaching the tracking roll 24 as a gap holding member to the shaft-shaped regulating member 52, the shaft-shaped regulating member 52 and the photosensitive drum 1 are attached to the end of the photosensitive drum 1.
Is formed so as to form a gap holding member 1a formed of a ridge for holding a gap with the surface. The interval between the gap holding members 1a is set wider than the cleaning area of the cleaning blade 5a. Even if the gap holding member 1a is formed on the photosensitive drum 1, it does not hinder the formation of an image in a cleaning process or the like. There is no such thing. The gap holding member 1a can also serve as a gap holding member with the developing roll. Also in this embodiment, as shown in FIG. 41, if the regulating member 52 is made rotatable by receiving a driving force by coming into contact with the gap holding member 1a,
A similar effect can be obtained for noise. Moreover,
Since the outer peripheral surface of the gap holding member 1a is slightly larger than the diameter of the photosensitive drum 1, the regulating member 5 receiving a driving force is provided.
2 is higher than the surface speed of the photosensitive drum 1, and the rotation of the film 20 is more stable than the configuration of the embodiment shown in FIG. 38 in which the tracking roll 23 and the regulating member 52 are integrated.

Embodiment 2-4 FIG. 42 shows an embodiment of the invention according to claim 18, and the same parts as those in the embodiment shown in FIG. In the embodiment 2-4, the regulating member 53 and an urging member for urging the charging device 3 toward the photosensitive drum 1 are integrally formed. In this embodiment, as shown in FIGS. 42 to 44, a spring material made of stainless steel, for example, SUS304 having a plate thickness of 0.05 mm is bent so as to form a shaft portion 54 having a diameter of 3 mm, and one end portion thereof is provided. A regulating member 53 which is curved so as to form a spring portion 55 which is bent a plurality of times is used, and two regulating members 53 are directly attached to the image forming unit 6 in parallel. Furthermore, if the regulating member 53 formed by the spring member is routed to the outer surface of the image forming unit 6, the regulating member 53 can also serve as a power supply member from the main body side, and the number of components can be reduced, that is, the number of components can be reduced. Costs can be reduced. The tracking rollers 24 as gap holding members are rotatably mounted on the two shaft portions 54 of the regulating member 53 at both ends in the longitudinal direction.

Furthermore, instead of using a stainless spring material as the regulating member 53, as shown in FIG.
The shaft portion 54 of the spring member 55 made of stainless steel may be formed short and used as a bearing member of the shaft-shaped regulating member 52.

Embodiment 3-1 FIG. 46 shows an embodiment of the present invention described in claim 22 and claim 23. The same parts as those in the embodiment shown in FIG. The third embodiment will be described.
In -1, the relative speed ratio of the flexible member to the photosensitive member is set to a predetermined value or more, so that the noise generated when the flexible member moves in contact with the photosensitive member is reduced. It is configured.

That is, the charging device 3 according to this embodiment
As described above with reference to FIGS. 4 and 5, etc., the cylindrical film 20 acting as a charging electrode, the regulating rods 21 and 21 contained therein, the tracking roll 24 as a gap holding member, And a biasing member for biasing the rod assay toward the body drum 1, and the cylindrical film 20 is attached so as to be sandwiched between the regulating rods 21 and 21 and the photosensitive drum 1. . In this state, the photosensitive drum 1 rotates and the film 20
When a voltage is applied to the photosensitive drum 1 and the film 20
An electrostatic attraction force is generated during this time, and the film 20 rotates at substantially the same speed as the photosensitive drum 1, and at the same time, a discharge is started in a minute gap between the film 20 and the photosensitive drum 1, and the charging of the photosensitive drum 1 is stopped Done. The voltage application to the film 20 can be realized by providing a contact substance from outside, but it is also possible to apply a voltage through the regulating rods 21. According to such a charging device, the minute gap can be made long, and characteristics superior to those of the conventional charging device can be obtained at low cost.

In the above embodiment, an experiment was conducted to clarify the relationship between the noise level generated when the peripheral speed ratio V _film / V _PR between the cylindrical film 20 and the photosensitive drum 1 was changed.

FIG. 46 shows the relationship between the peripheral speed ratio V _film / V _PR of the cylindrical film 20 and the photosensitive drum 1 and the noise level.
As V _film / V _PR approaches 1, the noise level decreases, and when V _film / V _PR exceeds 0.9, the change becomes sharp (in addition,
Practically, if the noise level is 50 dB or less, there is no problem). This is because when the peripheral speed of the film 20 approaches the peripheral speed of the photosensitive drum 1, the portion that started to vibrate due to the electrostatic attraction force in the contact portion with the photosensitive drum 1 moves smoothly, so that the vibrating portion repeatedly occurs. This is considered to be because the number of hits on the photosensitive drum 1 decreases, and when the peripheral speed ratio exceeds 0.9, the decrease becomes sharp.

[0134] Therefore, in this embodiment, the cylindrical film 20 and the peripheral speed ratio V _{fi lm} / V _PR of the photosensitive drum 1 is set to be 0.9 or more.

For this reason, in the charging device according to this embodiment, a high friction coefficient sheet is attached to both ends along the axial direction of the cylindrical film.

That is, in this embodiment, as shown in FIG. 47, a non-image area on the surface of the cylindrical film 20 has a high coefficient of friction with the photosensitive drum 1 such as an EPDM rubber sheet or a silicon rubber sheet. By wrapping 60, the followability of the cylindrical film 20 to the photosensitive drum 1 is improved. In the case of the charging device 3, even if the rotation speed of the photosensitive drum 1, that is, the process speed is increased, the film 20
The peripheral speed ratio V _film / V _PR between the photosensitive drum 1 and the photosensitive drum 1 can be set to 0.9 or more at which the above-mentioned noise can be reduced, and the quietness can be maintained.

Embodiment 2-2 FIG. 48 shows an embodiment according to the twenty-fourth aspect of the present invention. An embodiment according to claim 24 will be described with reference to FIG. In this embodiment, the ability of the film 20 to follow the photosensitive drum 1 is improved by wrapping a sheet 61 having a high coefficient of friction with respect to the film 20 such as silicon rubber in a non-image area on the surface of the photosensitive drum 1. It is configured to enhance. According to the charging device 3, even when the rotation speed of the photoconductor drum 1 is increased, the film peripheral speed ratio is set to 0.1.
9 or more, and quietness can be maintained.

Embodiment 3-3 FIG. 49 shows an embodiment of the present invention. An embodiment according to claim 25 will be described with reference to FIG. In this embodiment, the regulating member is composed of two rods 62 and 63, and a charging voltage is applied from the rod 63. In order to make the contact point on the upstream side in the rotation direction of the film 20 a line contact,
The rod 62 is made of an aluminum deformed material having a triangular cross section and the downstream contact portion is made in surface contact, so that the rod 63 is made of a deformed material having a round shape. this is,
Since the vertical force applied to the regulating portion is large on the upstream side in the rotation direction of the film 20, the contact area is reduced, so that the frictional resistance that hinders the rotation of the film 20 is reduced. Since the vertical resistance of the power supply is relatively small, the contact area is increased, and the electrical contact for power supply is ensured.

According to the charging device 3, even when the speed is increased, the electrical contact of the power supply section can be ensured while maintaining the peripheral speed ratio of the film 20 at 0.9 or more. Can be maintained. The relationship between the upstream and the downstream is not limited to the present embodiment,
If the process speed is relatively slow and the power supply performance is more important than the reduction of frictional resistance, the surface contact shape on the upstream side,
A line contact shape may be provided on the downstream side.

Further, in this embodiment, the frictional resistance was reduced by selecting the shape of the restricting portion. However, a means such as a surface treatment for reducing the frictional resistance such as buffing of the restricting portion, or a slippery material such as polyacetal was used. The same effect can be obtained by means of forming a regulating member with a material, means of applying a lubricant such as molybdenum disulfide to a regulated location, means of lapping a low friction coefficient sheet such as a fluororesin sheet at a regulated location, and the like. Can be given. Claim 2
Means for applying a lubricant such as molybdenum disulfide to a part or the entire surface of the film 20 at the regulation point according to the method described in No. 7; Means such as performing low friction resistance surface treatment such as mirror finishing,
Means for providing a low friction coefficient layer such as a fluorine-based material on a part or the entire surface of the regulation point facing surface during film formation,
The same effect can be obtained by providing a film with a low frictional resistance.

Embodiment 3-4 FIG. 50 shows an embodiment according to the twenty-eighth aspect of the present invention. In this embodiment, the regulating member is not formed of a rod or a shaft, but is formed of a hollow pipe material formed by bending a thin flat plate into a triangular cross section. The restricting member 70 having a triangular cross section has a horizontal plate portion 71 as a bottom side thereof, which is arranged in parallel with a tangent to the photosensitive drum 1. In the regulating member 70, a minute opening 72 is formed along the longitudinal direction at a corner on the upstream side in the rotation direction of the photosensitive drum 1, and air is blown out from the opening 72 to remove the film 20. By slightly floating, the frictional resistance between the regulating member 70 and the film 20 is reduced.

A power supply member 73 for supplying power to the film 20 is provided on the surface of the cylindrical film 20.
Are arranged so as to contact in the vicinity of the upstream side of the opening 72 of the regulating member 70. For this reason, the cylindrical film 20 is pressed against the power supply member 73 by compressed air injected from the opening 72 of the regulating member 70, and the contact between the cylindrical film 20 and the power supply member 73 is reduced. Can be obtained reliably. Further, the regulating member 7
The corner portion of the photoconductor drum 1 on the downstream side in the rotation direction is formed in an R shape so that the contact resistance between the cylindrical film 1 and the regulating member 70 can be reduced.

FIG. 51 shows a modification of the above-described embodiment. In this modification, the place where power is supplied to the cylindrical film is different from that of the above-described embodiment. In this modification, the position for supplying power to the cylindrical film 20 is set not on the upstream side in the rotation direction of the photosensitive drum 1 but on the downstream side.

That is, in this modified example, as shown in FIG. 51, the position for supplying power to the cylindrical film 20 is set to be the corner of the regulating member 70 on the downstream side in the rotation direction of the photosensitive drum. Then, the cylindrical film 20
A nozzle 74 that blows air so as to press the film 20 against the regulating member 70 is provided on the outer side.

Embodiment 3-5 FIG. 52 shows an embodiment of the present invention according to claim 29. The same parts as those of the above embodiment are denoted by the same reference numerals and explained. Inside the cylindrical film 20, two driven rotation rods 75, 76 are rotatably provided, and these two driven rotation rods 75, 7 are provided.
The rotation of 6 causes the cylindrical film 20 to rotate smoothly.

FIG. 53 shows a reference example .
In the reference example , the regulating member is formed by two rotatable rods 77,
And a rod 78 on the downstream side in the rotation direction of the film.
Are rotationally driven by a driving device (not shown). The charging speed of the charging device 3 is 110 m.
Even when the speed was increased to m / s, good chargeability and quietness could be maintained.

FIG. 54 shows the relationship between the peripheral speed ratio V _rod / V _PR of the drive rod and the photosensitive drum 1 and the noise level. Referring to the change in the film peripheral speed at this time, until _{V ro d / V PR = 1.0} , but the film 20 to follow the peripheral speed of the rod, the electrostatic the V _rod / V _PR is 1.0 or more It follows the peripheral speed of the photosensitive drum 1 by the attraction force. Therefore, the noise level became extremely low when V _rod / V _PR was 0.9 to 1.2. When V _rod / V _PR is 1.2 or more, the deformation state of the film 20 becomes extremely unstable due to the interference between the driving force received from the photosensitive drum 1 and the driving force received from the rod 78, and the film 20 is likely to vibrate. Therefore, it is considered that the noise level is slightly increased.

FIG. 55 shows a reference example .
In the reference example , two driven rotating collars 79 and 80 are provided inside the cylindrical film 20, and among these two driven rotating collars 79 and 80, the downstream side in the rotation direction of the photoconductor drum 1. , A disk-shaped member 81 that is driven to rotate via the film 20 is disposed in contact with the driven rotary collar 80 located at the position. The above-mentioned driven rotating collar 7
Reference numerals 9 and 80 are made of conductive polyacetal or the like, and a fixed shaft 82 made of SUS or the like is inserted therein. The disk-shaped member 81 is made of rubber or the like, and is mounted two along the longitudinal direction of the drive shaft 83. However, it is needless to say that three or more disk-shaped members may be provided. The above disk-shaped member 81
Is set to a value equal to the peripheral speed of the photosensitive drum 1, for example. The disc-shaped member 81 ensures that the film 20 is rotated,
Is displaced in the horizontal direction, the disk-shaped member 81 has a function of releasing the force by bending and correcting the walk phenomenon, thereby preventing the end of the film 20 from being damaged.
By using the charging device 3 configured as described above, good chargeability and quietness could be maintained up to a process speed of 150 mm / s.

Embodiment 4-1 FIG. 56 shows an embodiment of the invention according to claim 30. The same parts as those in the embodiment shown in FIG. In this embodiment, at both ends in the longitudinal direction of the regulating member, separated portions are provided in which the gap between the regulating member and the image carrier is set to be large.

That is, in this embodiment, as shown in FIGS. 56 to 58, a rod-shaped restricting member 21 is used, and both ends thereof are cut into a D-shaped cross section 85. As described above, when the D-shaped section 85 is not formed at both ends of the regulating rods 21 and 21, the cylindrical film 2
Since the rod portion exposed to the outside of 0 is close to the photosensitive drum 1, there is a possibility that a leak may occur from the rod to the photosensitive drum 1. On the other hand, for example, when a voltage of AC 2 kv _Pp is applied to the regulating rods 21, 21, the section 85 of the regulating rods 21 having the D-shaped cross section is separated from the photosensitive drum 1 by about 0.3 mm. By fixing toward the photosensitive drum 1, the distance from the photosensitive drum 1 becomes a non-discharge condition, and leakage to the photosensitive drum 1 is prevented.

The restricting rod 21 configured as described above,
As shown in FIG. 56 to FIG. 58, the regulating rods 21, 21 and the photosensitive drum 21 are provided with steps having D-shaped cross sections 85, 85 on opposite surfaces of the photosensitive drum 1 at both ends thereof. 1 can be designed under conditions that optimize the discharge area and stabilize the rotation of the film 20 and can be designed independently of the conditions for avoiding leakage from the regulating member 50 to the photosensitive drum 1. Becomes

In FIG. 59, when the cylindrical film 20 is rotated by receiving a driving force from the photosensitive drum 1, the cylindrical film 20 receives a force in the thrust direction with the rotation, and
, A so-called walk phenomenon that moves along the axial direction occurs. The maximum movement amount p of the film 20 due to this walk
On the other hand, when the distance q between the end of the D-shaped cross section at both ends of the regulating member 50 and the end of the cylindrical film 20 is increased, the regulating member 50 located outside the photosensitive drum 1 and the film 20 is increased. , There is always a gap equal to or longer than the distance corresponding to the discharge starting voltage, so that even if a walk occurs, leakage from the regulating rods 21 and 21 to the photosensitive drum 1 is prevented, and the regulating member It is not necessary to apply a treatment such as an insulating coat to both ends, and cost can be reduced.

In FIG. 60, the regulating rods 21, 2
1. Distance m between the ends of D-shaped section 85 provided at both ends
Is smaller than the axial length l of the cylindrical film 20 to be externally fitted and longer than the image area width, so that the inner part of the end of the D-shaped section 85 which is the power supply point of the regulating rods 21 and 21 is formed. Since the portion (the shortest distance from the photosensitive drum) always overlaps the image area, even if the cylindrical film 20 moves due to the aforementioned walk, it is possible to prevent the occurrence of power supply failure at the end of the image area. Can be.
The difference between the width n of the image area and the distance m between the inner ends of the D-shaped cross sections 85 provided at both ends of the regulating rods 21 and 21 is set to, for example, about 1 mm on one side, and the cylindrical film 20 is formed. Is different from the distance m between the inner ends of the D-shaped sections 85 provided at both ends of the regulating rods 21 and 21.
For example, it is set to about 1 to 2 mm on one side.

As described above, by providing the D-shaped cross-section 85 at the ends of the regulating rods 21, 21, the gap between the ends of the regulating rods 21, 21 and the photosensitive drum 1 can be set large. Thus, it is possible to reliably prevent leakage from the ends of the regulating rods 21 and 21 to the photosensitive drum 1 side. Therefore, as shown in FIG. 61, even when the nip amount is set to a large value on the positive side, that is, when the regulating rods 21 and 21 are brought closer to the surface of the photosensitive drum 1 and the AC current value is increased, the regulating rods 21 and 21 are increased. Does not leak from the end to the photosensitive drum 1 side.

FIG. 61 shows the relationship between the nip amount (the distance between the regulating member and the photosensitive member) and the value of the flowing AC current. According to this graph, the AC current value greatly fluctuates with a slight change in the nip amount. Therefore, the gap holding member is formed of a material and a shape having excellent wear resistance, for example, a tracking roll 24 made of polyacetal. Further, the film has a smaller mass than that of the roll charging, and the electrostatic attraction acts on the film, so that the film comes into stable contact with the photoreceptor and can be stably charged regardless of the axial length.

FIG. 62 shows another modification of the above-described embodiment, in which a stepped shaft is used as a regulating member. In this embodiment, as shown in FIG. 38, even when the regulating member 21 has a structure rotatable with respect to the holding member, the regulating member 21 is formed by using a stepped shaft.
The distance between the portion exposed to the photosensitive drum 1 and the photosensitive drum 1 becomes a non-discharge condition, and leakage to the photosensitive drum 1 is prevented.

Embodiment 5-1 FIG. 63 shows an embodiment of the present invention described in claim 32 of the present invention. The same parts as those in the embodiment shown in FIG. To explain, in this embodiment,
It is configured to provide a regulation releasing means for releasing the regulation of the shape of the tubular film by the regulating member. Further, in this embodiment, the charging device is attached to the image forming unit that is detachably attached to the image forming apparatus main body, and the image forming unit is taken out of the image forming apparatus main body, so that the regulating member of the charging unit reduces the tubular film. It is configured to provide a regulation release means for releasing the regulation of the shape.

In FIG. 63, reference numeral 90 denotes a housing of the image forming unit 6, and an opening 91 is provided in a portion of the housing 90 corresponding to the upper portion of the charging device 3. The distal end of the nip control member 93 connected to the cartridge cover 92 on the main body 7 side of the image forming apparatus is inserted into the opening 91 when the image forming unit 6 is mounted on the main body 7 of the image forming apparatus. It has become.
A guide portion 95 that guides a distal end portion 94 of the nip control member 93 is provided continuously with an opening 91 provided in the housing 90 of the image forming unit 6. The guide portion 95 of the housing 90 of the image forming unit 6 includes
A block 96 is provided to be vertically movable. On the other hand, at both ends of the regulating rods 21 of the charging device 3,
A rod holding member 25 is provided, and the rod holding member 25 is vertically movably held by a gap holding member 97. Further, the rod holding member 25 is urged upward by a coil spring 98, and a coil spring 99 as an elastic member is interposed between the rod holding member 25 and the block 96.

In this embodiment, in a state before the image forming unit 6 is mounted on the image forming apparatus, that is, in a state in which the user keeps the image forming unit 6 as a spare, the housing 90 of the image forming unit 6 is mounted. The provided block 96 is not pressed down by the nip control member 93 provided on the cartridge cover 92 on the main body 7 side of the image forming apparatus. As a result, the rod holding member 25 is moved upward by the elastic force of the coil spring 98 as shown in FIG.
Since the cylindrical film 20 is not pressed by the regulating rod 21, it is possible to prevent the cylindrical film 20 from being deformed.

When the image forming unit 6 is used after replacing it with a used one, as shown in FIG.
A block 96 provided in a housing 90 of the image forming unit 6 is pushed down by a nip control member 93 provided in a cartridge cover 92 on the main body 7 side of the image forming apparatus. Therefore, the rod holding member 25 is pushed down by the block 96 via the coil spring 99, and the cylindrical film 20 is pressed by the regulating rod 21, so that the cylindrical film 20 is Curvature of drum 1 and regulating rod 2
It becomes a state of bending according to the curvature determined by the position of (1). In this state, the surface of the photosensitive drum 1 is uniformly charged by the cylindrical film 20 as described above.

As described above, in the above-described embodiment, when the image forming unit 6 incorporating the charging device according to the embodiment of the present invention is not used, the state in which the cylindrical film 20 of the charging device 3 is bent. When the image forming unit 6 incorporating the charging device 3 is not used for a long period of time, the cylindrical film 20 of the charging device 3 is deformed. However, it is possible to reliably prevent the occurrence of uneven charging. When the image forming unit 6 is actually used by being incorporated into the main body 7 of the image forming apparatus,
By moving the regulating rod 21, the cylindrical film 20 is bent by the regulating rod 21 and is brought into contact with the surface of the photosensitive drum 1, so that the charging of the photosensitive drum 1 is good. In addition, it can be performed reliably.

As a result, when the image forming unit 6 is not mounted on the apparatus main body 7, the nip of the film 20 to the photosensitive drum 1 is always released, and the cross-sectional shape of the film 20 during long-term storage is permanently deformed. Can be prevented from occurring. Since the cross-sectional shape of the film when the nip is not nip is circular, the film elastic modulus in the circumferential direction during the nip becomes constant, and a stable potential convergence can be obtained without changing the discharge region.

Note that the nip release of the cylindrical film 20 is not performed when the image forming unit 6 is attached to or detached from the apparatus main body 7, but the block 98 or the rod holding member 25 is removed.
38, by providing a regulation releasing means made of a solenoid or the like for directly moving up and down, as described in claim 37, when the image forming apparatus is not operating, the regulating member of the charging means prevents the tubular film from moving. It may be configured to release the restriction on the shape.

The other constructions and operations are the same as those of the embodiment shown in FIGS. 2 to 7, and a description thereof will be omitted.

[0165]

As described above, according to the present invention, the electrostatic latent image carrier is charged through the minute gap by the flexible member, instead of being charged in the contact portion, and is stable at low cost. Charging method and charging device having improved charging performance,
And an image forming apparatus using the same.

Further, according to the present invention, it is possible to provide a charging method, a charging device, and an image forming apparatus using the same, which can reduce the generation of charging noise and can perform uniform charging.

[Brief description of the drawings]

FIGS. 1A and 1B are a perspective view and a sectional view showing a schematic configuration of a charging device according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of an image forming apparatus to which the charging device according to the present invention is applied.

FIG. 3 is a perspective view of a main part showing an embodiment of the charging device according to the present invention.

FIG. 4 is a sectional view showing an embodiment of an image forming apparatus to which the charging device according to the present invention is applied.

FIG. 5 is a perspective view showing a main part of the charging device according to the embodiment of the present invention in use.

FIG. 6 is a sectional view showing a state of use of an embodiment of the charging device according to the present invention.

FIG. 7 is a perspective view showing a regulating member of the charging device.

FIGS. 8A to 8C are schematic views respectively showing discharge regions of the charging device.

FIGS. 9A and 9B are schematic diagrams respectively showing a discharge region of a conventional charging device.

FIG. 10 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIGS. 11A to 11C are schematic diagrams respectively showing discharge regions of the charging device.

FIG. 12 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 13 is a sectional view showing another embodiment of the film.

FIG. 14 is a sectional view showing another embodiment of the photosensitive drum.

FIG. 15 is an explanatory diagram showing parameters of the charging device according to one embodiment of the present invention.

FIG. 16 is a configuration diagram showing a state in which each parameter of the charging device according to the embodiment of the present invention is changed.

FIG. 17 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 18 is a graph showing the charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 19 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 20 is a graph showing the charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 21 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 22 is a graph showing the charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 23 is a graph showing the charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 24 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 25 is a graph showing charging characteristics of an embodiment of the charging device according to the present invention.

FIG. 26 is a graph showing the relationship between film rigidity and sound pressure in one embodiment of the charging device according to the present invention.

FIG. 27 is a graph showing the relationship between the type of film and the vibration sound in one embodiment of the charging device according to the present invention.

FIG. 28 is a graph showing the relationship between the type of film and the vibration sound in one embodiment of the charging device according to the present invention.

FIG. 29 is a graph showing the elastic characteristic of one embodiment of the charging device according to the present invention.

FIG. 30 is a graph showing an elastic characteristic of the charging device according to one embodiment of the present invention.

FIG. 31 is a graph showing a relationship between a use time and a slip amount of the charging device according to one embodiment of the present invention.

FIG. 32 is a sectional view showing another embodiment of the charging device according to the present invention.

FIG. 33 is a sectional view showing a modification of the regulating member.

FIGS. 34 (a) and 34 (b) are configuration diagrams each showing a conventional charging device.

FIG. 35 is a perspective view showing an embodiment of the invention described in claim 14;

FIG. 36 is a longitudinal sectional view of the same.

FIG. 37 is a cross-sectional configuration diagram of the same.

FIG. 38 is a perspective view showing an embodiment of the invention described in claim 16;

FIG. 39 is a sectional view of the same.

FIG. 40 is a perspective view showing an embodiment of the invention described in claim 17;

FIG. 41 is a sectional view of the same.

FIG. 42 is a perspective view showing an embodiment of the present invention.

FIG. 43 is a sectional view of the same.

FIG. 44 is a perspective view of the essential part.

FIG. 45 is a perspective view of a main part showing a modification.

FIG. 46 is a graph showing an experimental example of the invention described in claim 22;

FIG. 47 is a perspective view showing an embodiment of the invention described in claim 23;

FIG. 48 is a perspective view showing an embodiment of the invention according to claim 24. FIG.

FIG. 49 is a perspective view showing an embodiment of the invention described in claim 25;

FIG. 50 is a sectional view showing an embodiment of the invention described in claim 28;

FIG. 51 is a sectional view showing a modification.

FIG. 52 is a sectional view showing an embodiment of the invention described in claim 29;

FIG. 53 is a sectional view showing a reference example .

FIG. 54 is a graph showing an experimental example of a reference example .

FIG. 55 is a perspective view showing a reference example .

FIG. 56 is a perspective view showing an embodiment of the invention described in claim 30 ;

FIG. 57 is a sectional view of the same.

FIG. 58 is a perspective view showing an embodiment of the invention described in claim 30 ;

FIG. 59 is an explanatory sectional view of the same.

FIG. 60 is an explanatory sectional view of the same.

FIG. 61 is a configuration diagram showing a relationship between a nip amount and an AC current value.

FIG. 62 is a perspective view showing a modification of the invention according to claim 30. FIG.

FIG. 63 is a sectional view showing an embodiment of the invention described in claim 32 ;

FIG. 64 is a sectional configuration view of a main part showing the operation state of FIG. 63.

FIGS. 65 (a) and (b) are schematic diagrams each showing a shape change when the tubular film is left as it is.

[Explanation of symbols]

 01 cylindrical film, 02 rod, 03 photoconductor.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Akanuma 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Yoshio Inoue 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (56) References JP-A-6-149004 (JP, A) JP-A-7-72712 (JP, A) JP-A-5-333665 (JP, A) JP-A-5-181323 (JP, A) JP-A-1 JP-A-172858 (JP, A) JP-A-2-28669 (JP, A) JP-A-7-20678 (JP, A) JP-A-4-232977 (JP, A) JP-A-4-268584 (JP, A) JP-A-5-72869 (JP, A) JP-A-5-273844 (JP, A) JP-A-6-11945 (JP, A) JP-A-6-11952 (JP, A) 75458 (JP, A) JP-A-6-175465 (JP, A) JP-A-6-202443 (JP, A) JP-A-6-258916 (JP, A) JP-A-6-266202 (JP, A) JP-A-5-188733 (JP, A) JP-A-4-161965 (JP, A) JP-A-4-335685 (JP, A) JP-A-5-257362 (JP, A) JP-A-6-95524 (JP, A) JP-A-7-5149 (JP, U) Kaihei 7-5150 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 13/02 G03G 15/02

Claims (34)

(57) [Claims] 1. A charging method for charging an electrostatic latent image carrier using a tube-shaped flexible member as a charging electrode, wherein the tube-shaped flexible member is replaced with the tube-shaped flexible member. a plurality of restricting members are not in direct contact with the electrostatic latent image bearing member through the inside disposed being and the tubular flexible member is brought into contact to the surface of the latent electrostatic image bearing member, an electrostatic latent The rotational force of the image carrier alone is applied to the flexible tube
Driven to rotate the tubular flexible member
The flexible member and the electrostatic latent image carrier to such an extent that
Contacting the door, by electrostatically attracted to the tubular flexible member to the surface of the electrostatic latent image bearing member, the curvature of the tubular flexible member of the electrostatic latent image bearing member Tomo and close to the curvature
The charging method characterized by charging the latent electrostatic image bearing member through a minute gap by the tubular flexible member. 2. A charging device for charging an electrostatic latent image carrier using a tubular flexible member as a charging electrode, wherein the tubular flexible member is provided inside the tubular flexible member. Without directly contacting the electrostatic latent image carrier via the member,
Further, a plurality of regulating members are provided for bringing the tubular flexible member into contact with the electrostatic latent image carrier, and the tubular flexible member is moved by the regulating member to the electrostatic latent image carrier. The tube-shaped flexible member is brought into contact with the surface and the rotational force of only the electrostatic latent image carrier is
Driven to rotate the tubular flexible member
The flexible member and the electrostatic latent image carrier to such an extent that
Contacting the door, by electrostatically attracted to the tubular flexible member to the surface of the electrostatic latent image bearing member, the curvature of the tubular flexible member of the electrostatic latent image bearing member Tomo and close to the curvature
A charging device for the electrostatic latent image bearing member by the tubular flexible member, characterized in that charging via the micro gap. 3. An image forming apparatus comprising: an electrostatic latent image carrier; a tubular flexible member as a charging electrode; and voltage applying means for applying a voltage to the tubular flexible member. Inside the tubular flexible member, without directly contacting the electrostatic latent image carrier via the tubular flexible member,
Further, a plurality of regulating members are provided for bringing the tubular flexible member into contact with the electrostatic latent image carrier, and the tubular flexible member is moved by the regulating member to the electrostatic latent image carrier. The tube-shaped flexible member is brought into contact with the surface and the rotational force of only the electrostatic latent image carrier is
Driven to rotate the tubular flexible member
The flexible member and the electrostatic latent image carrier to such an extent that
Contacting the door, by electrostatically attracted to the tubular flexible member to the surface of the electrostatic latent image bearing member, the curvature of the tubular flexible member of the electrostatic latent image bearing member Tomo and close to the curvature
An image forming apparatus , wherein the electrostatic latent image carrier is charged via a minute gap by the tubular flexible member. 4. The charging device according to claim 2, wherein the regulating member is provided in the vicinity of a region where the tubular flexible member and the electrostatic latent image carrier come into contact with or come closest to each other. . 5. The image forming apparatus according to claim 3, wherein the restricting member is provided in the vicinity of a region where the tubular flexible member and the electrostatic latent image carrier come into contact with or come closest to each other. apparatus. 6. The charging device according to claim 2, wherein the power supply to the flexible member is performed by a regulating member. 7. The image forming apparatus according to claim 3, wherein the power supply to the flexible member is performed by a regulating member. 8. The regulating member includes: an upstream side in the rotation direction of the electrostatic latent image carrier and a downstream side in the rotation direction of the electrostatic latent image carrier in a region where the flexible member contacts or comes closest to the electrostatic latent image carrier. The charging device according to claim 4, wherein the shape of the flexible member is regulated by both of them. 9. The regulating member includes: an upstream side in the rotation direction of the electrostatic latent image carrier and a downstream side in the rotation direction of the electrostatic latent image carrier in a region where the flexible member comes into contact with or comes closest to the electrostatic latent image carrier. The image forming apparatus according to claim 5, wherein the shape of the flexible member is regulated by both of them. 10. The charging device according to claim 2, wherein the surface of the regulating member is treated with a high-resistance thin film. 11. The image forming apparatus according to claim 3, wherein the surface of the regulating member is treated with a high-resistance thin film. 12. The charging device according to claim 2, wherein a charging electrode having a high resistance surface layer provided on the surface of a flexible member in which a conductive agent is dispersed is used. 13. The image forming apparatus according to claim 3, wherein a charging electrode having a high resistance surface layer provided on a surface of a flexible member in which a conductive agent is dispersed is used. 14. An electrostatic latent image carrier that is not in direct contact with the electrostatic latent image carrier through the rotatable conductive tubular film via the tubular film. Arrange a plurality of regulating members to be abutted,
Like a film the tube, is brought into contact to the surface of the electrostatic latent image bearing member by said regulating member, an electrostatic latent image charge of
By transmitting the rotational force of the holding body only to the tubular film
To the extent that the tubular film can be driven and rotated,
Contact the tubular film with the electrostatic latent image carrier
Is, by electrostatically adsorbing the tubular film on the surface of the electrostatic latent image bearing member, is brought close to the curvature of the tubular film to the curvature of the electrostatic latent image bearing member together
A charging device for charging the electrostatic latent image carrier through the minute gap with the tubular film ; an urging member for urging the regulating member toward the electrostatic latent image carrier side; And a gap holding member for holding a gap with the latent image carrier. 15. The charging device according to claim 14, wherein the gap holding member is provided on a film holding member that holds the tubular film and the regulating member. 16. The charging device according to claim 14, wherein the gap holding member is provided on a regulating member. 17. The charging device according to claim 14, wherein the gap holding member is provided on an electrostatic latent image carrier. 18. The charging device according to claim 14, wherein the urging member is provided integrally with a film holding member or a regulating member that holds the tubular film and the regulating member. 19. The charging device according to claim 14, wherein a coefficient of friction of a side surface of the gap holding member that contacts the tubular film is increased. 20. The charging device according to claim 16, wherein the regulating member and the gap holding member are integrally formed, and the regulating member is rotatably disposed. 21. The charging device according to claim 16, wherein said regulating member is rotatably disposed. 22. The charging device according to claim 4, wherein a peripheral speed ratio of the rotating flexible member to a peripheral speed of the electrostatic latent image carrier is 0.9 or more. 23. The charging device according to claim 4, wherein regions having a high coefficient of friction are provided at both ends along the axial direction of said flexible member. 24. The charging device according to claim 4, wherein an area having a higher friction coefficient than an image forming area is provided in a non-image area on the surface of the electrostatic latent image carrier. 25. A contact area of at least a contact portion, which is located on the upstream side in the moving direction of the electrostatic latent image carrier, of the contact portion of the regulating member that contacts the flexible member, is set to be small. The charging device according to claim 4. 26. The charging device according to claim 4, wherein at least one of the contact portions of the regulating member that makes contact with the flexible member has been subjected to a process of reducing contact resistance. 27. The charging device according to claim 4, wherein at least one of the contact portions of the flexible member that comes into contact with the regulating member has been subjected to a process of reducing contact resistance. 28. The charging device according to claim 4, wherein the frictional resistance is reduced by blowing air from at least one of the contact portions of the regulating member that contact the flexible member. 29. The charging device according to claim 4, wherein a rolling contact member is provided on at least one of the contact portions of the regulating member that contact the flexible member. 30. An interior of a rotatable conductive tubular film which is not in direct contact with the electrostatic latent image carrier via the tubular film, and which is provided with the tubular film as an electrostatic latent image carrier. Arrange a plurality of regulating members to be abutted,
The tubular film, is brought into contact to the surface of the electrostatic latent image bearing member by said regulating member, the electrostatic latent image bearing
By transmitting the rotational force of the body only to the tubular film,
This is enough to allow the tubular film to be driven and rotated.
The tubular film is brought into contact with the electrostatic latent image carrier.
Allowed, by electrostatically adsorbing the tubular film on the surface of the electrostatic latent image bearing member, it is brought close to the curvature of the tubular film to the curvature of the electrostatic latent image bearing member together,
In a charging device for charging an electrostatic latent image carrier through a minute gap by the tubular film, a separation section in which a gap between the regulation member and the image carrier is set to be large at both ends in a longitudinal direction of the regulating member. A charging device comprising: 31. A distance between inner ends of spaced portions provided at both ends in a longitudinal direction of the regulating member, is shorter than an axial length of the tubular film, and is smaller than a width of an image area of an image carrier. 31. The charging device according to claim 30, wherein the charging device is also long. 32. Inside the rotatable conductive tubular film, the tubular film is not directly in contact with the electrostatic latent image carrier through the tubular film, and the tubular film is brought into contact with the electrostatic latent image carrier. Arrange a plurality of regulating members to be abutted,
The tubular film, is brought into contact to the surface of the electrostatic latent image bearing member by said regulating member, the electrostatic latent image bearing
By transmitting the rotational force of the body only to the tubular film,
This is enough to allow the tubular film to be driven and rotated.
The tubular film is brought into contact with the electrostatic latent image carrier.
Allowed, by electrostatically adsorbing the tubular film on the surface of the electrostatic latent image bearing member, it is brought close to the curvature of the tubular film to the curvature of the electrostatic latent image bearing member together,
In a charging device for charging the electrostatic latent image carrier through the minute gap by the tubular film, in a state where the voltage application to the conductive tubular film is turned off,
A charging device, comprising: a regulation release means for releasing regulation of the shape of the tubular film by the regulation member. 33. An electrostatic latent image carrier and a rotatable conductive tubular film inside the tubular film without directly contacting the electrostatic latent image carrier via the tubular film. arranged a plurality of <br/> regulating member to abut on the electrostatic latent image bearing member, said tubular film, is brought into contact to the surface of the electrostatic latent image bearing member by said regulating member, the electrostatic The rotational force of only the latent image carrier is
The film is transmitted to the
To the extent possible, the tubular film and the electrostatic latent image
Contacting the carrier, by electrostatically adsorbing the tubular film on the surface of the electrostatic latent image bearing member, it is brought close to the curvature of the tubular film to the curvature of the electrostatic latent image bearing member together, A charging unit for charging the electrostatic latent image carrier with the tubular film through a minute gap, wherein the charging unit is attached to an image forming unit detachable from the main body of the image forming apparatus; Release means for removing the regulation of the shape of the tubular film by the regulating member of the charging means by removing the image forming unit from the image forming apparatus main body in a state where the voltage application to the non-conductive tubular film is turned off. An image forming apparatus comprising: 34. An electrostatic latent image carrier and a rotatable conductive tubular film inside the tubular film without directly contacting the electrostatic latent image carrier via the tubular film. arranged a plurality of <br/> regulating member to abut on the electrostatic latent image bearing member, said tubular film, is brought into contact to the surface of the electrostatic latent image bearing member by said regulating member, the electrostatic The rotational force of only the latent image carrier is
The film is transmitted to the
To the extent possible, the tubular film and the electrostatic latent image
Contacting the carrier, by electrostatically adsorbing the tubular film on the surface of the electrostatic latent image bearing member, it is brought close to the curvature of the tubular film to the curvature of the electrostatic latent image bearing member together, Charging means for charging the electrostatic latent image carrier through the minute gap by the tubular film , wherein the image forming apparatus does not operate when the conductive tubular film is charged. An image forming apparatus comprising: a regulation release unit that releases regulation of the shape of the tubular film by the regulation member of the charging unit in a state where the voltage application is turned off.