JP3359285B2 - Charging method, charging device, and image recording apparatus using the charging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a charging method and a charging device for charging an object to be charged. More specifically, the present invention relates to a charging method and a charging device for charging a surface of a member to be charged by a flexible charging member forming a nip with the member to be charged.

[0002] The present invention also relates to an image recording apparatus (image forming apparatus) such as a copying machine or a printer using the charging device as a charging means for an image carrier.

[0003]

2. Description of the Related Art Conventionally, for example, in an image recording apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, an image carrier (a member to be charged) such as an electrophotographic photosensitive member or an electrostatic recording dielectric has a required polarity and potential. A corona charger (a corona discharger) has often been used as a charging device for uniformly performing a charging process (including a static elimination process).

A corona charger is a non-contact type charging device, for example, includes a discharge electrode such as a wire electrode and a shield electrode surrounding the discharge electrode, and has a discharge opening facing an image carrier which is a member to be charged. The image carrier is charged in a predetermined manner by exposing the surface of the image carrier to a discharge current (corona shower) generated by applying a high voltage to the discharge electrode and the shield electrode.

In recent years, medium- and low-speed image recording apparatuses have advantages such as low ozone and low power as a charging device for a member to be charged such as an image carrier as compared with a corona charger. Many contact charging devices have been proposed and put into practical use.

[0006] The contact charging device contacts an object to be charged such as an image carrier with a conductive charging member such as a roller type (charging roller), a fur brush type, a magnetic brush type or a blade type.
A predetermined charging bias is applied to this charging member (contact charging member / contact charger, hereinafter referred to as a contact charging member) to charge the surface of the charged body to a predetermined polarity and potential.

[0007] The contact charging mechanism (charging mechanism,
In the charging principle), there are two types of charging mechanisms, a corona charging system and a direct charging system, and each characteristic appears depending on which one is dominant.

[0008] Discharge Charging System (Discharge Charging Mechanism) This is a system in which the surface of a member to be charged is charged by a discharge phenomenon occurring in a minute gap between the contact charging member and the member to be charged.

Since the discharge charging system has a fixed discharge threshold for the contact charging member and the member to be charged, it is necessary to apply a voltage higher than the charging potential to the contact charging member. Further, although the amount of generation is much smaller than that of the corona charger, it is in principle unavoidable to generate a discharge product, so that the harmful effects of active ions such as ozone are inevitable.

[0010] Direct Charging System (Direct Injection Charging Mechanism) This is a system in which the surface of a member to be charged is charged by injecting charge directly from the contact charging member to the member to be charged. It is also called direct charging, injection charging, or charge injection charging.

More specifically, a medium-resistance contact charging member is brought into contact with the surface of a member to be charged, and charges are directly injected into the surface of the member without a discharge phenomenon, that is, without basically using discharge. It is. Therefore, even when the voltage applied to the contact charging member is equal to or lower than the discharge threshold, the member to be charged can be charged to a potential corresponding to the applied voltage. Since the direct charging system does not involve generation of ions, no adverse effects are caused by the discharge products.

However, because of direct charging, the contact property of the contact charging member with the member to be charged greatly affects the charging property.
Therefore, it is necessary to form the contact charging member more densely, have a large speed difference from the member to be charged, and contact the member to be charged more frequently.

A) Roller Charging In a contact charging device, a roller charging system using a conductive roller (charging roller) as a contact charging member is preferable in terms of charging stability, and is widely used.

In the roller charging, the charging mechanism is dominated by the discharge charging system.

The charging roller is made of a conductive or medium-resistance rubber or foam. In some cases, these are laminated to obtain desired characteristics.

The charging roller has elasticity in order to obtain a constant contact state with a member to be charged (hereinafter, referred to as a photosensitive member). Therefore, frictional resistance is large, and in many cases, the charging roller is driven by the photosensitive member. It is driven with a slight speed difference. Therefore, even if direct charging is attempted, the charging mechanism of the conventional roller charging is the discharge charging, because the reduction of the absolute charging capability, the lack of contact, the unevenness on the roller, and the charging unevenness due to the adhesion of the photoconductor are unavoidable. The system is dominant.

FIG. 9 is a graph showing an example of charging efficiency in contact charging. The horizontal axis represents the bias applied to the contact charging member, and the vertical axis represents the photoconductor charging potential obtained at that time.

The charging characteristic in the case of the conventional roller charging is represented by A. That is, charging starts after passing a discharge threshold of about -500V. Therefore, when charging to -500 V, a DC voltage of -1000 V is applied, or
A general method is to apply an AC voltage of 1200V between peaks so as to always have a potential difference equal to or greater than a discharge threshold in addition to the charging voltage of 00V DC, so that the photoconductor potential converges on the charging potential.

More specifically, when a charging roller is pressed against an OPC photosensitive member having a thickness of 25 μm, the surface potential of the photosensitive member increases when a voltage of about 640 V or more is applied. Start, and after that, slope 1 with applied voltage
, The photoconductor surface potential increases linearly. This threshold voltage is defined as charging start voltage Vth.

That is, in order to obtain the photosensitive member surface potential Vd required for electrophotography, the charging roller needs Vd + Vth
Therefore, a DC voltage higher than required is required. A method of applying only a DC voltage to the contact charging member to perform charging in this manner is referred to as a “DC charging method”.

However, in the DC charging method, since the resistance value of the contact charging member fluctuates due to environmental fluctuation or the like, and if the film thickness changes due to the photoreceptor being scraped, Vt
Since h fluctuated, it was difficult to set the potential of the photoconductor to a desired value.

For this reason, as disclosed in Japanese Patent Application Laid-Open No. 63-149669, a DC voltage corresponding to a desired Vd has a peak-to-peak voltage of 2 × Vth or more, as disclosed in JP-A-63-149669. An “AC charging method” in which a voltage on which an AC component is superimposed is applied to a contact charging member is used. This is for the purpose of effect of leveling the potential by AC, and the potential of the charged body is V V which is the center of the peak of the AC voltage.
It converges to d and is not affected by disturbances such as the environment.

However, even in such a contact charging device, since the essential charging mechanism uses a discharge phenomenon from the contact charging member to the photosensitive member, the charging is applied to the contact charging member as described above. The voltage is required to be higher than the surface potential of the photoreceptor, and a small amount of ozone is generated.

When the AC charging system is used for uniform charging, further generation of ozone, vibration noise of the contact charging member and the photosensitive member due to the electric field of the AC voltage (AC charging noise).
And the deterioration of the surface of the photoreceptor due to the discharge becomes remarkable, which has been a new problem.

B) Fur brush charging In the fur brush charging, a member having a brush portion of a conductive fiber (a fur brush charger) is used as a contact charging member.
The conductive fiber brush portion is brought into contact with a photoreceptor as a member to be charged, and a predetermined charging bias is applied to charge the photoreceptor surface to a predetermined polarity and potential.

In the fur brush charging, the discharging mechanism is dominant in the charging mechanism.

As the fur brush charger, a fixed type and a roll type have been put to practical use. A fixed type is formed by folding a medium-resistance fiber into a base fabric and forming it in a pile shape and bonding it to an electrode. The roll type is formed by winding a pile around a cored bar. A fiber density of about 100 fibers / mm ² can be obtained relatively easily, but the contact property is still insufficient to perform sufficiently uniform charging by direct charging, and sufficiently uniform charging is performed by direct charging. It is necessary to make the speed difference such that it is difficult for the photoconductor to have a mechanical configuration, which is not practical.

The charging characteristics of the fur brush charging when a DC voltage is applied are as shown in FIG. 9B. Therefore, also in the case of the fur brush charging, in both the fixed type and the roll type, charging is performed by applying a high charging bias and using a discharge phenomenon.

C) Magnetic Brush Charging The magnetic brush charging uses a member (magnetic brush charger) having a magnetic brush portion formed as a brush by constraining conductive magnetic particles magnetically with a magnet roll or the like as a contact charging member. The magnetic brush portion is brought into contact with a photosensitive member as a member to be charged, and a predetermined charging bias is applied to charge the surface of the photosensitive member to a predetermined polarity and potential.

In the case of this magnetic brush charging, the charging mechanism is dominated by the direct charging system described above.

By using conductive magnetic particles having a particle diameter of 5 to 50 μm as a constituent of the magnetic brush portion and providing a sufficient speed difference from the photosensitive member, uniform direct charging can be achieved.

As shown in C of the charging characteristic graph of FIG.
It is possible to obtain a charging potential substantially proportional to the applied bias.

However, there are other adverse effects, such as the complicated device configuration and the conductive magnetic particles constituting the magnetic brush portion falling off and adhering to the photoreceptor.

Japanese Patent Application Laid-Open No. Hei 6-3921 proposes a method of injecting charges into a charge holding member such as a trap level on a photoreceptor surface or conductive particles of a charge injection layer to perform contact injection charging. . Since the discharge phenomenon is not used, the voltage required for charging is only the desired surface potential of the photoconductor, and no ozone is generated. Furthermore, since no AC voltage is applied, no charging noise is generated, and the charging method is excellent in ozone-less and low-power compared to the roller charging method.

D) Toner Recycling System (Cleanerless) In a transfer-type image recording apparatus, a transfer residual developer (toner) remaining on a photoconductor (image carrier) after transfer is exposed to light by a cleaner (cleaning device). Although the waste toner is removed from the body surface, it is desirable that the waste toner does not come out from the viewpoint of environmental protection. Therefore, a toner recycling system (or toner recycling system) that removes the cleaner and removes the transfer residual toner on the photoreceptor after transfer from the photoreceptor by "development simultaneous cleaning" using a developing device and collects and reuses it in the developing device Process) image recording devices have also emerged.

Simultaneous development cleaning means that the toner remaining on the photoreceptor after transfer is developed during the next and subsequent steps, that is, the photoreceptor is subsequently charged and exposed to form a latent image. This is a method of recovering by a picking bias (fogging potential difference Vback which is a potential difference between a DC voltage applied to the developing device and a surface potential of the photoconductor). According to this method, the transfer residual toner is collected in the developing device and reused after the next process. Therefore, waste toner can be eliminated and troublesome maintenance can be reduced. Also, because it is cleaner-less, there are great advantages in terms of space,
The size of the image recording apparatus can be greatly reduced.

In the toner recycling system, the transfer residual toner is not removed from the surface of the photoreceptor by a dedicated cleaner as described above, but is transferred to a developing device via a charging means and used again in the developing process. Therefore, when contact charging is used as a charging means for the photoconductor, how to charge the photoconductor in a state where an insulating toner is interposed in a contact portion between the photoconductor and the contact charging member is an issue. Has become. In the above-described roller charging or fur brush charging, transfer residual toner on a photoreceptor is diffused to form a non-pattern, and a large amount of bais is applied and charging by discharge is often used. In magnetic brush charging, since powder is used as a contact charging member, there is an advantage that the magnetic brush portion of the conductive magnetic particles as the powder can flexibly contact the photoconductor and charge the photoconductor, but the equipment configuration is complicated. That is, there is a large adverse effect due to the drop of the conductive magnetic particles constituting the magnetic brush portion.

E) Powder Coating on Contact Charging Member The contact charging device has a configuration in which powder is applied to the contact surface of the contact charging member with the surface to be charged in order to prevent charging unevenness and perform stable and uniform charging. As disclosed in Japanese Patent Application Laid-Open No. 7-99442, the contact charging member (charging roller) is driven to rotate (no speed difference driving) by the member to be charged (photoreceptor), and generates ozone as compared with a corona charger such as a scorotron. Although the generation of objects is remarkably reduced, the charging principle is still mainly charging by discharging as in the case of the roller charging described above. In particular, since a voltage obtained by superimposing an AC voltage on a DC voltage is applied in order to obtain more stable charging uniformity, generation of ozone products due to discharge is increased. Therefore, when the apparatus is used for a long period of time or when the cleaner-less image recording apparatus is used for a long period of time, adverse effects such as image deletion due to ozone products are likely to appear. Japanese Patent Application Laid-Open No. 5-150539 discloses that in an image forming method using contact charging, charging inhibition due to toner particles or silica fine particles adhering to the surface of a charging unit during repeated image formation is prevented. Therefore, it is disclosed that a developer contains at least visible particles and conductive particles having an average particle size smaller than the visible particles. However, this contact charging is based on the discharge charging mechanism, and has the above-mentioned problem due to the discharge charging, not the direct injection charging mechanism.

[0039]

1) As described in the section of the prior art described above, in the conventional contact charging, direct charging is performed with a simple configuration using a charging roller or a fur brush as a contact charging member. To perform the charging, the surface of the contact charging member was rough and a close contact with the member to be charged was not ensured, and direct charging was impossible.

Further, the contact charging member easily picks up foreign matter from the surface of the member to be charged and is easily stained. If the stain is insulative, poor charging is likely to occur.

Therefore, in the contact charging, even when a simple member such as a charging roller is used as the contact charging member, regardless of the contamination of the contact charging member, the direct charging is more excellent in charging uniformity and stable for a long period of time. It is expected that charging can be realized, that is, ozone-less injection charging at a low applied voltage can be realized with a simple configuration.

An object of the present invention is to meet the above-mentioned demand for contact charging.

2) In the image recording apparatus, when a contact charging device is adopted as a charging means for the image carrier, ozone-less injection charging can be realized at a low applied voltage with a simple configuration such as a charging roller as a contact charging member. If this is possible, it is extremely effective in terms of device configuration and performance.

Regarding the contamination of the contact charging member in the case of a transfer type image recording apparatus employing a contact charging device as the charging means of the image carrier, a developer image (toner image) formed and carried on the image carrier is recorded. Even in the case of an image recording apparatus provided with a dedicated cleaner for removing transfer residual toner on the image carrier after transfer to the body, the transfer residual toner on the image carrier is completely removed by the cleaner. It is difficult for the toner to slightly pass through the cleaner and is carried by the movement of the surface of the image carrier to the charging portion, which is the contact portion between the contact charging member and the image carrier. The charging member is gradually contaminated with toner.

Since the conventional toner is an insulator, the presence of the toner in the charging portion, which is the contact portion between the contact charging member and the image carrier, or the contamination of the contact charging member by the toner is a charge inhibiting factor. Yes, it causes charging failure.

Particularly, in an image recording apparatus of a toner recycling system (cleanerless), a dedicated cleaner for removing residual toner on the surface of the image carrier after transfer is not used. Since the transfer residual toner is carried as it is by the movement of the surface of the image carrier to the charging portion which is the contact portion between the image carrier and the contact charging member, the contact charging member is significantly contaminated with toner.

Accordingly, the present invention relates to a contact charging type image recording apparatus, a contact charging type / transfer type image recording apparatus, and a contact charging type / transfer type / toner recycling system image recording apparatus. By using a simple member such as a roller , and irrespective of toner contamination of the contact charging member, the ozone-less direct charging and toner recycling system can be performed without problems at a low applied voltage, and high-quality image formation can be performed for a long time. To keep them crossing,
An object of the present invention is to maintain high-quality image formation for a long time even after outputting an image having a high image ratio.

[0048]

The present invention provides a charging method, a charging device, and an image recording apparatus using the charging device, which are characterized by the following constitutions.

(1) A charging method for charging the surface of a member to be charged by a flexible charging member forming a nip with the member to be charged, wherein the charging member moves at a speed difference with respect to the member to be charged. the charging member includes a foam on the surface thereof, riff the charging accelerating particles on the surface of the charging member by supplying a charging accelerating particles to the surface of the charging member by rubbing the surface of the charging member
Charging method characterized by have a fur brush to thresholds.

(2) The volume resistivity of the charge accelerating particles is 10 ¹²
The charging method according to (1), wherein the charging rate is Ω · cm or less. (3) The charging method according to (1), wherein the volume resistance value of the charge promoting particles is 10 ¹⁰ Ω · cm or less.

(4) The charging member is a rotating member, and is driven with a speed difference with respect to the member to be charged, and a voltage is applied to the member. Charging method.

(5) The fur brush in contact with the charging member has a shape of a fur brush roller in which fibers spread radially, and is driven to rotate, in any one of (1) to (4). The charging method described in the above. (6) The fur brush which comes into contact with the charging member is free to swing in the longitudinal direction of the charging member, and has a means for swinging the fur brush.
The charging method described in (1).

(7) The charging method according to any one of (1) to (6), wherein a stirrer for stirring the charge promoting particles is disposed in a housing of the charge promoting particle supply device.
Law . (8) In any one of (1) to (7), a regulating means for regulating an excessively supplied charge accelerating particle to the charging member after the fur brush in the rotation direction of the charging member is provided. The charging method according to one of the above.

(9) A charging device for charging the surface of a member to be charged by a flexible charging member forming a nip with the member to be charged, wherein the charging member moves at a speed difference with respect to the member to be charged. the charging member includes a foam on the surface thereof, riff the charging accelerating particles on the surface of the charging member by supplying a charging accelerating particles to the surface of the charging member by rubbing the surface of the charging member
A charging device, characterized in that it have a fur brush to thresholds.

(10) The volume resistivity of the charge accelerating particles is 10
The charging device according to (9), wherein the charging device has a resistivity of ¹² Ω · cm or less. (11) The charging device according to (9), wherein a volume resistance value of the charge promoting particles is 10 ¹⁰ Ω · cm or less. (12) The charging device according to any one of (9) to (11), wherein the charging member is a rotating body, and is driven with a speed difference with respect to the member to be charged, and a voltage is applied. .

(13) The fur brush in contact with the charging member has a shape of a fur brush roller in which fibers spread radially, and is driven to rotate (9) to (1).
The charging device according to any one of 2). (14) The fur brush in contact with the charging member is free to swing in the longitudinal direction of the charging member, and has a means for swinging the fur brush. The charging device as described in the above. (15) The charging device according to any one of (9) to (14), wherein a stirrer for stirring the charge promoting particles is disposed in a housing of the charge promoting particle supply device.

(16) In the rotation direction of the charging member, a regulating means for regulating the charge accelerating particles excessively supplied to the charging member after the fur brush is provided (9) to (15). charging instrumentation according to any one of
Place . (17) An image recording apparatus for performing image recording by applying an image forming process including a step of charging the image carrier to the image carrier, wherein the step of charging the image carrier is performed in steps (9) to ( 16) An image recording device, which is the charging device according to any one of the above items.

(18) Image carrier, charging means for charging the image carrier, and forming an electrostatic latent image on the charged surface of the image carrier
A latent image forming unit , a developing unit for visualizing the electrostatic latent image with a developer, a transfer unit for transferring the developer image to a recording medium, and a cleaning unit for cleaning the image carrier after the transfer The image carrier is an image recording apparatus repeatedly used for image formation, and the charging means for charging the image carrier is the charging device according to any one of (9) to (16). Image recording device. (19) image bearing member and a latent image forming hands of forming a charging unit that charges the image bearing member, an electrostatic latent image on the charged surface of the image bearing member
A step , a developing means for visualizing the electrostatic latent image with a developer,
Transfer means for transferring the developer image to the recording medium, and the developing means also serves as a cleaning means for collecting the developer remaining on the image carrier after transferring the developer image to the recording medium. The image carrier is an image recording apparatus repeatedly used for image formation, and the charging means for charging the image carrier is the charging device according to any one of (9) to (16). Image recording device. (20) The information writing means for forming an electrostatic latent image on the charged surface of the image carrier is an image exposure means.
8) or the image recording apparatus according to (19).

<Operation> a) Direct charging (injection charging) The charging promoting particles are conductive particles for the purpose of assisting charging, and the present invention realizes uniform and stable direct charging by using the conductive particles. are doing. The volume resistance of the charge accelerating particles is 1 ×
It is desirably 10 ¹² Ω · cm, preferably 1 × 10 ¹⁰ Ω · cm.

[0060] That is, those which cause the contact charging of the member to be charged a flexible contact charging member and the nip at a charging portion charging accelerating particles by interposing member to be charged, the charging member is the
Since the surface is a foam, the charge accelerating particles
And the presence of the charge-promoting particles in the charging portion, which has a large frictional resistance due to the lubricant effect of the particles, making it difficult to contact the member to be charged with a speed difference as it is. Even if a contact charging member such as a charging roller is used, it can be easily and easily brought into contact with the surface of the member to be charged with an effective speed difference, and the contact can be made. The charging member comes into close contact with the surface of the member to be charged via the charge accelerating particles, and comes into contact with the surface of the member to be charged more frequently.

Since a speed difference can be provided between the contact charging member and the member to be charged, the chance that the charge promoting particles contact the member to be charged in the nip portion between the contact charging member and the member to be charged is greatly increased. A high contact property can be obtained, and the charge promotion particles existing in the charging portion, which is a nip portion between the contact charging member and the charged member, rub the surface of the charged member without gaps to directly charge the charged member. Injection becomes possible, and direct charging (injection charging) is dominant in contact charging of the member to be charged by the contact charging member.

As a configuration for providing a speed difference, the contact charging member is driven to rotate to provide a speed difference from the member to be charged. The contact charging member can be moved in the same direction as the moving direction of the surface of the member to be charged to have a speed difference, but the charging property of the injection charging is determined by the ratio of the peripheral speed of the member to be charged to the peripheral speed of the contact charging member. In order to obtain the same peripheral speed ratio as in the reverse direction, the rotation speed of the contact charging member in the forward direction is larger than that in the reverse direction. This is advantageous.

The peripheral speed ratio described here is: peripheral speed ratio (%) = (peripheral speed of charging member−peripheral speed of member to be charged) / peripheral speed of member to be charged × 100 (the peripheral speed of the charging member is charged at the nip portion. It is a positive value when the member surface moves in the same direction as the surface of the member to be charged).

An insulative substance which is a charge inhibiting factor is interposed in a charging portion which is a nip portion between a member to be charged and a contact charging member, or a contact charging member is contaminated with such an insulative substance. Even in this case, since the charge promoting particles are present in the charging portion, which is a nip portion between the member to be charged and the contact charging member, the contact resistance of the contact charging member to the member to be charged and the contact resistance can be maintained. Ozone-less direct charging can be stably maintained over a long period of time with an applied voltage, and uniform charging properties can be provided.

B) The charging member whose surface is made of a foam is used to hold the charging promoting particles.
In addition, a fur brush is provided to supply the charge-promoting particles to the charging member by contacting the surface thereof, thereby accelerating the charge from the charging portion, which is a nip portion between the member to be charged and the contact charging member, as the device is used. Even if the particles fall off, the charging portion is replenished with the charge-promoting particles to prevent the charging characteristics from being lowered, and the above-described direct charging property can be stably maintained for a long period of time. In addition, the fur brush is
By contacting the foam, charging of the surface of the charging member is promoted.
Particles can be removed.
And the circulation of the charge promoting particles can be appropriately performed. Immediately
That is, even if the surface of the charging member has irregularities such as foam,
Removes charge accelerating particles by using a brush
It will be easier.

In an image recording apparatus having a toner recycling (cleanerless) configuration, even if transfer residual toner which has a great adverse effect on the charging property is carried to and interposed in the charging section, the charging of the contact charging member is performed by the charging promoting particle supply device. The supply of the accelerating particles is appropriately performed, and a sufficient amount of the electrification accelerating particles always exist in the charging portion, so that the above-described direct charging property can be stably maintained for a long time.

The supply of the charge-promoting particles to the contact charging member may be performed, for example, by bringing a blade into contact with the contact-charging member, holding the charge-promoting particles between the blade and the contact charging member, and bringing a certain amount of the charge-promoting particles into contact with the blade. Although it is possible to adopt a configuration in which the toner is supplied to the surface of the charging member, the toner may be mixed into the charging accelerating particles and the circulation of the toner may be interrupted, so that it may not be possible to appropriately supply the charging accelerating particles.

In the present invention, the charge-promoting particle supply device for supplying the charge-promoting particles to the contact charging member comprises a fur brush contacting the contact charging member and the charge-promoting particles to refresh the contact charging member. By circulating the charge accelerating particles, the charge accelerating particles are appropriately supplied.

The fur brush in contact with the contact charging member has a shape of a fur brush roller in which fibers spread radially,
By rotating, the refreshing on the contact charging member and the stirring of the charge-promoting particles are performed, so that the supply of the charge-promoting particles is further uniformed and stabilized.

The fur brush in contact with the contact charging member is free to swing in the longitudinal direction of the charging member, and the swing means of the fur brush promotes the circulation of the charge promoting particles and stabilizes the supply of the charge promoting particles. Let it.

The circulation of the charge promoting particles is further promoted by disposing a stirring member for stirring the charge promoting particles in the housing of the charge promoting particle supply device.

In the rotation direction of the contact charging member, a regulating means for regulating the excessively supplied charge promoting particles to the contact charging member after the fur brush is provided, so that the charge promoting particles can be applied to the contact charging member. This prevents excessive supply and enables uniform supply of the charge-promoting particles.

By contacting the fur brush with the contact charging member and supplying the charge-promoting particles, the contact charging member is refreshed, the circulation of the charge-promoting particles is promoted, and the mixed toner is disturbed to stably charge. Acceleration particles can be applied to form a stable injection charging device. Further, by forming the fur brush in a roller shape and rotating the fur brush, the charge-promoting particles can be stirred at the same time, and a stable charging device can be configured with a simpler configuration. It is also possible to use the fur brush as a regulating member for the charge accelerating particles. Also, in a recording apparatus that recycles toner without using a cleaning device, the pattern-like toner remaining on the image carrier as a transfer residue and transferred to the contact charging member is non-patterned to prevent image deterioration due to transfer residual toner. There is also the effect of doing.

C) Thus, a high charging efficiency which cannot be obtained by the conventional roller charging or the like is obtained, and a charging potential substantially equal to the voltage applied to the contact charging member can be applied to the member to be charged. Even when a simple member such as a charging roller is used, and regardless of contamination of the contact charging member, the applied bias necessary for charging the contact charging member is a voltage corresponding to the charging potential required for the member to be charged. It is possible to realize, with a simple configuration, a stable and safe contact charging device that does not use a discharge phenomenon, that is, a direct charging device having a low applied voltage, ozone-less, excellent charging uniformity, and stable performance over a long period of time. it can.

By using the charging device as a charging means for the image carrier, a contact charging type image recording device, a contact charging type / transfer type image recording device, and a contact charging type / transfer type / toner recycling system The image recording apparatus of the above uses a simple member such as a charging roller or a fur brush as a contact charging member, and has a problem of low voltage ozone-less direct charging and a toner recycling system regardless of toner contamination of the contact charging member. To maintain high quality image formation (image recording) without image deterioration due to charging failure for a long time, and to maintain high quality image formation for a long time even after outputting an image with a high image ratio. And so on.

In an image recording apparatus of a toner recycling system (cleanerless), since the contact charging member is in contact with the image carrier at a speed difference, the transfer unit transfers the image from the contact charging member to the image carrier. The pattern of the transfer residual toner that has reached the charging portion, which is the nip portion of the carrier, is disturbed and collapsed,
In the halftone image, the previous image pattern portion does not appear as a ghost.

The presence of the charge-promoting particles in the charging portion, which is the nip portion between the contact charging member and the image carrier, enables the contact charging member to maintain close contact with the image carrier and contact resistance. Irrespective of contamination of the member by transfer residual toner, ozone-less direct charging can be stably maintained at a low applied voltage for a long time, and uniform charging properties can be provided.

The transfer residual toner adhering to and mixed into the contact charging member is gradually discharged from the contact charging member onto the image carrier, moves to the image carrier surface, reaches the developing site, and is simultaneously cleaned (collected) by the developing means. (Toner recycling).

[0079]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 (FIGS. 1 and 2) FIG. 1 is a schematic structural diagram of an example of an image recording apparatus according to the present invention. FIG. 2 is an enlarged cross-sectional model view of the contact charging device.

The image recording apparatus of this embodiment is a laser printer of a contact charging type utilizing a transfer type electrophotographic process.

(1) Overall Schematic Configuration of Printer 1 is an image carrier, and this embodiment is a rotary drum type negative OPC photosensitive member (a negative photosensitive member, hereinafter referred to as a photosensitive drum) of φ30 mm. The peripheral speed of the photosensitive drum 1 is 50 mm / sec in the clockwise direction of the arrow a (= process speed P).
(S, printing speed).

Reference numeral 2 denotes an outer peripheral surface of the photosensitive drum 1 having a predetermined polarity.
This is a contact charging device that uniformly charges to a potential, and includes a charging member 21 that contacts the photosensitive drum 1 and a charging promotion particle supply device 22 that supplies the charging promotion particles m to the charging member.

In this embodiment, the charging member 21 is the photosensitive drum 1
And a conductive elastic roller (hereinafter, referred to as a charging roller) as a contact charging member disposed by being brought into contact with a predetermined pressing force.

N is a charging nip portion (charging portion) between the photosensitive drum 1 and the charging roller 21. The charging roller 21 is rotationally driven in the charging nip N in a direction (counter) opposite to the rotation direction of the photosensitive drum 1 as shown by an arrow b, and contacts the surface of the photosensitive drum 1 with a speed difference.

The outer peripheral surface of the rotating charging roller 21 is supplied with the charging promoting particles m by the charging promoting particle supply device 22, and is charged to the charging nip N between the photosensitive drum 1 and the charging roller 21. Intervenes.

The charging roller 21 is supplied with a predetermined charging bias from a charging bias applying power source S1 (−700 V in this embodiment).
Is applied.

As a result, the peripheral surface of the rotary photosensitive drum 1 is uniformly contact-charged to the same potential as the charging bias applied to the charging roller 21 by the direct charging (injection charging) method.

The charging roller 21 of the contact charging device 2
The charge accelerating particle supply device 22, direct charging, and the like will be described in detail in the following section (2).

Reference numeral 7 denotes a laser beam scanner (exposure device) including a laser diode, a polygon mirror, and the like. The laser beam scanner 7 outputs a laser beam intensity-modulated in accordance with a time-series electric digital pixel signal of target image information, and scans and exposes the uniformly charged surface of the rotary photosensitive drum 1 with the laser beam. .

By the scanning exposure L, an electrostatic latent image corresponding to the target image information is formed on the surface of the rotating photosensitive drum 1.

Reference numeral 3 denotes a developing device (developing device). The electrostatic latent image on the surface of the rotating photosensitive drum 1 is developed as a toner image at the developing site A by the developing device 3.

The developing device 3 of this embodiment is a reversal developing device using a one-component magnetic toner (negative toner) as the developer t. Reference numeral 3a denotes a non-magnetic rotary developing sleeve as a developer-carrying / transporting member in which a magnet roll 3b is included. Toner t as a developer in the developing device 3 is regulated in a process of being transported on the rotary developing sleeve 3a. The blade 3c receives the thickness regulation and the charge application.

The toner t coated on the rotary developing sleeve 3a is rotated by the rotation of the developing sleeve 3a.
Is transported to a development site (development area) A, which is a portion opposed to the development sleeve 3a. A developing bias voltage is applied to the developing sleeve 3a from a developing bias applying power source S2.

In this embodiment, the developing bias voltage is as follows: DC voltage: -500 V AC voltage: peak-to-peak voltage 1600 V, frequency 1.8 kHz
z, the superimposed voltage of the square wave.

Thus, the electrostatic latent image on the photosensitive drum 1 is reversely developed with the toner t.

The one-component magnetic toner t, which is a developer, is prepared by mixing a binder resin, magnetic particles, a coloring agent, a charge control agent, and the like, and performing kneading, pulverizing, and classifying processes. Etc. as an external additive. The weight average particle diameter (D4) of the toner was 7 μm.

Reference numeral 4 denotes a medium-resistance transfer roller as contact transfer means, which is brought into pressure contact with the photosensitive drum 1 at a predetermined pressure to form a transfer nip portion T. A transfer material 30 as a recording medium is fed to the transfer nip T from a paper feed unit (not shown) at a predetermined timing, and a predetermined transfer bias voltage is applied to the transfer roller 4 from a transfer bias application power source S3. As a result, the toner image on the photosensitive drum 1 side is sequentially transferred to the surface of the transfer material 30 fed to the transfer nip portion T.

The transfer roller 4 used in this embodiment is a cored bar 4a.
And a roller having a resistance value of 5 × 10 ⁸ Ω, and a voltage of +2.0 kV was applied to the cored bar 4a to perform transfer.

The transfer material 30 introduced into the transfer nip portion T is conveyed by nipping the transfer nip portion T, and the toner images formed and carried on the surface of the rotating photosensitive drum 1 on the surface side thereof are sequentially electrostatically and electrostatically charged. It is transferred by the pressing force.

Reference numeral 5 denotes a fixing device such as a heat fixing method. The transfer material 30 fed to the transfer nip portion T and having received the transfer of the toner image on the photosensitive drum 1 side is separated from the surface of the rotary photosensitive drum 1 and is introduced into the fixing device 5 to receive the fixation of the toner image. It is discharged out of the apparatus as an image formed product (print, copy).

Reference numeral 6 denotes a photosensitive drum cleaner (cleaning device). After the transfer of the toner image onto the transfer material 30, the transfer residual toner remaining on the drum surface of the rotary photosensitive drum 1 is a cleaning blade (elastic blade) in which the cleaning member 6a of the cleaner 6 abuts on the photosensitive drum 1 surface in this example. , Is cleaned and repeatedly provided for image formation.

The transfer residual toner scraped off from the surface of the photosensitive drum 1 by the cleaning blade 6a is accumulated as waste toner in the cleaner container.

[0103] (2) By forming the contact charging device 2 a) charging roller 21 is resistive layer 21b in the origination foam on a core metal 21a serving as a contact charging member of flexibility at the charging roller 21 present Example Created.

The medium resistance layer 21b is formulated with a resin (for example, urethane), conductive particles (for example, carbon black), a sulfide agent, a foaming agent and the like, and is formed in a roller shape on the core metal 21a. Thereafter, the surface was polished as necessary to prepare a charging roller 21 as a conductive elastic roller having a diameter of 12 mm and a longitudinal length of 200 mm.

When the roller resistance of the charging roller 21 of this embodiment was measured, it was 100 kΩ. The roller resistance is set between the core metal 21a and the aluminum drum while the charging roller 21 is pressed against an aluminum drum of φ30 mm so that a total pressure of 1 kg is applied to the core metal 21a of the charging roller 21.
V was applied and measured.

Here, the charging roller 2 as a contact charging member
It is important that 1 functions as an electrode. That is, it is necessary to obtain a sufficient contact state with the member to be charged by providing elasticity, and at the same time, it is necessary to have a resistance low enough to charge the moving member to be charged. On the other hand, it is necessary to prevent voltage leakage when a low withstand voltage defect site such as a pinhole is present in the member to be charged. When a photoreceptor for electrophotography is used as a member to be charged, 10 ⁴ -10
^{A 7} Ω resistor is desirable.

It is desirable that the surface of the charging roller 21 has micro unevenness so as to hold the charging promoting particles m.

If the hardness of the charging roller 21 is too low, the shape is not stable, so that the contact property with the member to be charged is deteriorated. If the hardness is too high, the charging nip N cannot be secured between the roller and the member to be charged. However, the microscopic contact with the surface of the member to be charged is deteriorated, so that the Asker C hardness is preferably in the range of 25 to 50 degrees.

[0109] As the material of the charging roller 21, as a material of the elastic body, EPDM, urethane, NBR, or silicone rubber, obtained by dispersing conductive material such as carbon black or metal oxides for the resistance adjustment IR etc. What made the thing foamed is mentioned. Further, it is also possible to adjust the resistance by using an ionic conductive material without dispersing the conductive substance.

The charging roller 21 is disposed so as to be pressed against the photosensitive drum 1 as a member to be charged with a predetermined pressing force against elasticity. In this embodiment, a charging nip portion N having a width of several mm is formed. It is.

In this embodiment, the charging roller 21 is rotated clockwise at approximately 80 rpm at a speed of about 80 rpm so that the surface of the charging roller and the surface of the photoreceptor move at opposite speeds in the charging nip portion N in opposite directions. Was. That is, the surface of the charging roller 21 as the contact charging member has a speed difference from the surface of the photosensitive drum 1 as the member to be charged.

Then, a DC voltage of -700 V was applied as a charging bias from the power supply S1 to the core metal 21a of the charging roller 21.

B) Charge-promoting particle supplier 22 The charge-promoting particle supplier 22 is disposed above the charging roller 21 and applies and supplies the charging-promoting particles m to the outer peripheral surface of the rotating charging roller 21. In this embodiment,
The means for supplying the charge promoting particles m by bringing the fur brush roller 22c (FIG. 2) into contact with the charging roller 21 is employed. The fur brush roller 22c refreshes the surface of the charging roller 21 and can hold a large number of the charge promoting particles m between the fibers, and can easily transfer the particles to the outer surface of the charging roller 21. It can be performed stably.

The charge accelerating particle supply device 22 of this embodiment includes a housing container 22b, a fur brush roller 22c, a regulating member 22a, a sealing sheet 22d, and a charge accelerating particle m.
Etc.

The housing container 22b includes the charging roller 21
The container is a horizontally long container having the same length as that of FIG.
Is housed.

The fur brush roller 22c contacts the charging roller 21 at an opening on the lower surface side of the housing container 22b over substantially the entire length of the roller, and rubs the outer surface of the charging roller to refresh and charge the charging roller 21. It serves to facilitate the application of the accelerating particles. The shafts at both ends are rotatably supported between both end plates of the housing container 22b in the housing container 22b. It is a member.

The fur brush roller 22c is a fur brush 22e formed by folding fibers into a base cloth and forming a pile.
Is wound around the cored bar 22f and fixed. The fiber density was about 500 fibers / mm ^{2 as} the folded density on the base cloth, and the length (free length) of the bristle feet was 3 mm. This 3m
The distance between the core metal 21a of the charging roller 21 and the core metal 22f of the fur brush roller 22c is adjusted so that the surface layer of the charging roller 21 is located at a position 2 mm from the surface layer of the core metal 22f with respect to the bristle feet of m. The fur brush roller 22c was brought into contact with the charging roller 21.

The regulating member 22a serves to regulate the charge-promoting particles excessively supplied to the charging roller 21. The regulating member 22a is a horizontally long blade member having substantially the same length as the charging roller 21, and the charging member 22a charges the housing container 22b. The roller 21 is fixedly arranged on the inner surface side of the side wall plate on the downstream side in the rotation direction of the roller 21 along the length of the side wall plate, and the lower side is brought into very close or light contact with the outer surface of the charging roller 21.

The sealing sheet 22d is a relatively long, horizontally elongated plastic sheet piece, and is configured to promote charging from the gap between the lower side of the side wall plate of the housing container 22b on the upstream side in the rotation direction of the charging roller 21 and the charging roller 21. It serves to prevent particle leakage. An inwardly bent edge is formed along the length of the lower side of the side wall plate on the upstream side in the rotation direction of the charging roller 21 of the housing container 22b, and a lower surface of the inwardly bent edge is formed along the length of the edge. The base side of the sealing sheet 22d is bonded and fixed, and the front end side is brought into very close or light contact with the outer surface of the charging roller 21. The sealing sheet 22d substantially closes the gap between the lower side of the side wall plate on the upstream side in the rotation direction of the charging roller 21 of the housing container 22b and the charging roller 21, thereby preventing the leakage of the charge promoting particles.

The charge accelerating particles m stored in the housing container 22b are held in a substantially enclosed space surrounded by the housing container 22b, the regulating member 22a, the sealing sheet 22d, and the upper surface of the charging roller 21. This prevents leakage and scattering outside the housing container 22b. A large number of charge promoting particles m are held by the fur brush 22e of the fur brush roller 22c disposed in the housing container 22b.

In this embodiment, conductive zinc oxide powder having a specific resistance of 10 ⁶ Ω · cm and an average particle diameter of 3 μm was used as the charge accelerating particles m.

As the material of the charge accelerating particles m, various kinds of conductive particles such as a mixture with other conductive inorganic particles such as metal oxides and organic substances, or a surface-treated mixture thereof can be used.

The particle resistance requires a specific resistance of 10 ¹² Ω · cm or less, more preferably 10 ¹⁰ Ω · cm or less, in order to transfer charges via the particles.

The resistance was measured by the tablet method and normalized. That is, about 0.5 g of a powder sample was placed in a cylinder having a bottom area of 2.26 cm ² , and 15 kg of pressure was applied to the upper and lower electrodes, and at the same time, a voltage of 100 V was applied to measure the resistance value. Was calculated.

The particle size is 50 in order to obtain good charging uniformity.
μm or less is desirable. In the present invention, the particle size when the particles constitute an aggregate is defined as the average particle size of the aggregate. For the measurement of the particle size, 100 or more samples were extracted from observation with an optical or electron microscope, the volume particle size distribution was calculated using the maximum chord length in the horizontal direction, and the 50% average particle size was determined.

There is no problem that the charge accelerating particles exist not only in the form of primary particles but also in the form of aggregated secondary particles. Regardless of the state of aggregation, the form is not important as long as the function as the charge promotion particles can be realized as an aggregate.

The charge-promoting particles are preferably white or nearly transparent so as not to hinder the exposure of the latent image, particularly when used for charging the photosensitive member, and are therefore preferably nonmagnetic.

In consideration of the fact that the charge accelerating particles are partially transferred from the photoreceptor to the recording medium 30, it is desirable that the color recording be colorless or white. Also,
In order to prevent light scattering due to particles during image exposure, the particle diameter is desirably equal to or smaller than the constituent pixel size. The lower limit of the particle size is considered to be 10 nm as a limit so that the particles can be stably obtained.

In the present embodiment, the fur brush roller 22c of the charge accelerating particle supply device 22 is
At the time of the rotational driving, a driving system (not shown) rotationally drives at a predetermined peripheral speed in the clockwise direction of arrow c.

[0130] The rotating charging roller 21 is provided with the charge accelerating particles m.
The outer peripheral surface is sufficiently refreshed by being rubbed and rubbed by the rotating fur brush roller 22 and receives the application of the charge accelerating particles m. The regulating member 22a disposed downstream of the fur brush roller 22c in the rotation direction of the charging roller regulates an appropriate amount of the charge-promoting particles m excessively applied to the charging roller 21 to supply a uniform charge-promoting particle m. Was possible.

The charge-promoting particles m applied to the outer surface of the charging roller 21 in a regulated amount by the charge-promoting-particle supply device 22 are supplied and charged by the subsequent rotation of the charging roller 21 to form a charging nip between the charging roller 21 and the photosensitive drum 1. Thus, a sufficient amount of the charge-promoting particles m is uniformly present in each portion of the charging nip N at all times.

(3) Direct Charging The presence of the charge-promoting particles m in the charging nip N has a large frictional resistance due to the lubricant effect of the particles m. Even if the charging roller 21 has been difficult to contact, it can be easily and effectively brought into contact with the photosensitive drum 1 surface with a speed difference. The charging roller 21 is connected to the photosensitive drum 1 via the particles m.
The surface is in close contact with the surface of the photosensitive drum 1 more frequently.

Since the speed difference can be provided between the charging roller 21 and the photosensitive drum 1, the chance that the charging promoting particles m contact the photosensitive drum 1 in the nip portion between the charging roller 21 and the photosensitive drum 1 is greatly increased. As a result, a high contact property can be obtained, and the charge promotion particles m present in the nip portion between the charging roller 21 and the photosensitive drum 1 rub the surface of the photosensitive drum 1 without gaps, so that charges can be directly injected into the photosensitive drum 1. As a result, contact charging of the photosensitive drum 1 by the charging roller 21 is dominated by direct charging (injection charging) due to the presence of the charge promoting particles.

Although the image recording apparatus (printer) of this embodiment is provided with the cleaner 6 for removing the transfer residual toner from the surface of the photosensitive drum 1 after the transfer, the transfer residual toner is actually removed from the surface of the photosensitive drum 1. It is difficult to completely remove,
In particular, in the cleaning using the elastic blade 6a used in the present embodiment, the fine powder having a small particle diameter passes through the blade 6a, so that the blade can be brought into contact without being turned up. Therefore, even in an image recording apparatus provided with the cleaner 6, the toner (insulating substance), which is a charge inhibiting factor that slightly escapes from the cleaner 6, is carried to the charging nip N and interposed therebetween. The charging roller 21 is contaminated with toner.

Even in such a case, since the charge promoting particles m are present in a sufficient amount in the charging nip portion N, which is the contact portion between the photosensitive drum 1 and the charging roller 21, the charging roller 2
1 and the decrease in the contact property due to the toner is compensated, and the precise contact property and the contact resistance of the charging roller 21 to the photosensitive drum 1 can be maintained, so that the ozone-less direct charging can be stably maintained at a low applied voltage for a long time. And uniform chargeability can be provided.

The provision of the charge-promoting particle supply device 22 for supplying the charge-promoting particles m to the charging roller 21 allows the charge-promoting particles m to move from the charging nip N between the photosensitive drum 1 and the charging roller 21 with use of the apparatus. Is charged, the charging nip N is replenished with the charge-promoting particles m, and the charge-promoting particles m are prevented from dropping or decreasing from the charge nip N, thereby preventing the charging characteristics from being lowered. It can be maintained stably for a long time.

In this manner, a high charging efficiency, which cannot be obtained by the conventional roller charging or the like as a contact charging device, is obtained, and a charging potential substantially equal to the voltage applied to the charging roller 21 can be applied to the photosensitive drum 1. Even when the simple charging roller 21 is used as the charging member, and regardless of the contamination of the charging roller 21, the applied bias necessary for charging the charging roller 21 is a voltage equivalent to the charging potential required for the photosensitive drum 1. In addition, it is possible to realize a stable and safe contact charging device that does not use a discharge phenomenon, that is, a direct charging device that is low in applied voltage and ozone-free, has excellent charging uniformity, and has stable performance for a long period of time with a simple configuration.

In a contact charging type image recording apparatus and a contact charging type / transfer type image recording apparatus, a simple charging roller 21 is used as a contact charging member and regardless of toner contamination of the charging roller 21. , Ozone-less direct charging at low applied voltage can be performed without any problem, and high-quality image formation can be maintained for a long time, and high-quality image formation can be maintained for a long time even after outputting an image with a high image ratio. And so on.

If the intervening amount of the charge-promoting particles in the charging nip N between the photosensitive drum 1 as the image carrier and the charging roller 21 as the contact charging member is too small, the lubricating effect of the particles cannot be sufficiently obtained. In addition, friction between the charging roller 21 and the photosensitive drum 1 is large, and it is difficult to rotate the charging roller 21 with a speed difference between the photosensitive drum 1 and the photosensitive drum 1.
That is, the driving torque becomes excessively large, and the surface of the charging roller 21 and the surface of the photosensitive drum 1 are shaved if the rotation is forcibly performed. Further, the effect of increasing the chance of contact by the particles may not be obtained, so that sufficient charging performance cannot be obtained. On the other hand, if the intervening amount is too large, the detachment of the charge-promoting particles from the charging roller 21 significantly increases, and adversely affects image formation. According to experiments, it is desirable that the intervening amount is not less than 10 ³ / mm ² . 10 ³
If the number is smaller than the number of pieces / mm ² , a sufficient lubricating effect and an effect of increasing the chance of contact cannot be obtained, resulting in a decrease in charging performance. More preferably, the intervening amount is 10 ^{3 to} 5 × 10 ⁵ pieces / mm ² . If the number exceeds 5 × 10 ⁵ particles / mm ² , the particles are remarkably increased into the photoconductor 1, resulting in an insufficient amount of light exposure on the photosensitive drum 1 regardless of the light transmittance of the particles themselves. 5 × 10 ⁵
When the number is less than the number of particles / mm ² , the amount of particles falling off is suppressed to be low, and the adverse effect can be improved. In the intervening amount range, the photosensitive drum 1
When the abundance of the particles dropped on the top is measured, 10 ² to 10 ⁵ particles /
Since it was mm ² , it is desired that the abundance which does not have an adverse effect on image formation be 10 ⁵ / mm ² or less.

A method for measuring the intervening amount and the abundance amount on the photosensitive drum 1 will be described. It is desirable to directly measure the interposed amount between the charging roller 21 and the charging nip portion N of the photosensitive drum 1, but most of the particles existing on the photosensitive drum 1 before coming into contact with the charging roller 21 move while moving in the opposite direction. In the present invention, the amount of particles on the surface of the charging roller 21 immediately before reaching the charging nip N is defined as the intervening amount. Specifically, the rotation of the photosensitive drum 1 and the charging roller 21 is stopped in a state where the charging bias is not applied, and the surfaces of the photosensitive drum 1 and the charging roller 21 are cleaned with a video microscope (OLYMPUS OVM10).
00N) and a digital still recorder (SR-3100 manufactured by DELTAS). Regarding the charging roller 21, the charging roller 21 is brought into contact with the slide glass under the same conditions as the contact with the photosensitive drum 1, and the contact surface is viewed from the back of the slide glass with a video microscope at 10 or more locations using a 1000 × objective lens. Taken. In order to separate individual particles from the obtained digital image, binarization processing was performed with a certain threshold value, and the number of regions where particles were present was measured using desired image processing software. Also, the photosensitive drum 1
The above abundance was measured by photographing the surface of the photosensitive drum 1 with the same video microscope and performing the same processing. The adjustment of the intervening amount was performed by setting the degree of application by the charge accelerating particle supply device 22.

<Embodiment 2> (FIG. 3) This embodiment is a printer of a toner recycling system (cleanerless) in which the cleaner 6 is eliminated from the printer of the first embodiment.

The other configuration of the apparatus is the same as that of the printer according to the first embodiment, and the description thereof will not be repeated.

In a cleanerless image recording apparatus,
Since a dedicated cleaner for removing the transfer residual toner on the photosensitive drum surface after the transfer is not used, the transfer residual toner on the photosensitive drum surface after the transfer is transferred to the charging nip portion N between the photosensitive drum 1 and the charging roller 21. Since the printer is transported as it is, the amount of toner interposed in the charging nip portion N is larger than that of the printer having the cleaner 6 of the first embodiment, and the amount of toner adhering to and mixing with the charging roller 21 is larger.

However, even in such a case, the charge promoting particles m are charged by the charge nip N between the photosensitive drum 1 and the charge roller 21.
Is sufficient to prevent the contamination of the charging roller 21 and to reduce the contact property due to the toner.
, It is possible to maintain the ozone-less direct charge stably at a low applied voltage for a long period of time, and to provide uniform chargeability.

Since the charging roller 21 is in contact with the photosensitive drum 1 with a speed difference, the transfer residual toner from the transfer nip portion T to the charging nip portion N of the charging roller 21 and the photosensitive drum 1 is removed. The pattern is disturbed and broken, so that the previous image pattern portion does not appear as a ghost in the halftone image.

It is desirable that the charging roller 21 is driven to rotate to temporarily collect and level the transfer residual toner, and that the rotation direction thereof is rotated in a direction opposite to the moving direction of the photosensitive drum surface.

The transfer residual toner is used for toner recycling.
Charging roller 21 of charging device 2 and charging promoting particle supply device 22
In this embodiment, the fur brush roller 22
(c) The charge promotion particle supply device 22 is constituted by the regulating member 22a and the like, and the charge promotion particles can be stably supplied to the charging roller 21 without scattering,
In particular, in the configuration of the toner recycling system (cleanerless) as in the present embodiment, there is a great effect that the transfer residual toner is circulated to the charging roller 21 without stagnation, and the charge promotion particles m can be supplied. That is, the supply of the charge accelerating particles m to the charging roller 21 and the toner leveling on the charging roller are simultaneously performed.

Then, close contact and contact resistance with the photosensitive drum 1 can be maintained, and direct charging becomes possible.

Further, the transfer residual toner mixed into the charging roller 21 and the charge accelerating particle supply device 22 is gradually discharged from the charging roller 21 onto the photosensitive drum 1 and moves to the developing portion A with the movement of the photosensitive drum surface. In step 3, cleaning (collection) is performed simultaneously with development (toner recycling). As described above, during the development simultaneous cleaning, the toner remaining on the photoreceptor 1 after transfer is developed during the subsequent image forming process, that is, the photoreceptor is subsequently charged and exposed to form a latent image, and the latent image is developed. In some cases, the fogging bias of the developing device, that is, the fog removing potential difference Vback, which is the potential difference between the DC voltage applied to the developing device and the surface potential of the photosensitive member.
Is to be recovered. In the case of the reversal development as in the printer in this embodiment, the simultaneous cleaning of development involves applying the electric field for collecting the toner from the dark portion potential of the photoconductor to the developing sleeve and attaching the toner from the developing sleeve to the bright portion potential of the photoconductor. This is done by the action of an electric field.

Further, in this embodiment, zinc oxide particles are used as the charge promoting particles m to be supplied to the charging roller 21. The zinc oxide particles as the charge promoting particles m negatively charge the toner in terms of the frictional charging characteristics with the toner. It has the property of being easily charged. That is, the toner has an effect of making the toner negative on the charging roller 21 and an effect of improving the toner discharging property.

By repeating the above steps, it is possible to directly charge the toner while maintaining toner recycling, and to maintain the charge for a long period of time.

<Embodiment 3> (FIG. 4) In the present embodiment, the configuration of the charge accelerating particle supply device 22 for the charging roller 21 of the charging device 2 in the printer (FIGS. 1 and 2) of the embodiment 1 is shown. This is changed as shown in FIG.

That is, the fur brush was changed to the non-rotating fixed fur brush 22g instead of the fur brush roller 22c that was driven to rotate. The housing container 22
A stirring member 22h for the charge-promoting particles m was newly disposed in the area b. Other configurations of the charge accelerating particle supply device 22 are described in the first embodiment.
Is the same as the configuration of the charge accelerating particle supply device 22 of the charging device 2 in FIG.

The non-rotating fixed fur brush 22g is a horizontally long member having substantially the same length as the charging roller 21, and is formed by fixing a fur brush formed by folding fibers into a base fabric and forming a pile on a support plate.

The fiber density is 500 as the folding density on the base cloth.
Approximately 1 / mm ² , hair length (free length) is 3m
m. The fur brush 22g was disposed in the housing container 22b so as to be non-rotatable by bringing the fur brush into contact with the charging roller 21.

In this embodiment, the agitating member 22h is disposed downstream of the non-rotating fixed fur brush 22g in the rotation direction of the charging roller in the housing container 22b. It is attached. The agitating member 22h is disposed in the housing container 22b in such a manner that both end shaft portions are rotatably supported between both end plates of the housing container 22b so as to be in non-contact with the charging roller 21, and has a length substantially equal to that of the charging roller 21. It is a horizontally long member.

In this embodiment, the agitating member 22h of the charge accelerating particle supply device 22 is rotated at a predetermined peripheral speed in the clockwise direction of the arrow d by a drive system (not shown) when the charging roller 21 is driven to rotate. did.

The rotating charging roller 21 is rubbed by the non-rotating fixed fur brush 22g in the charging-promoting particle supply device 22 to refresh the outer peripheral surface. Thereafter, the rotating stirring member 22h removes the adhesion of the charging-promoting particles m. receive. Then, the regulating member 22a regulated the charge promoting particles m excessively applied to the charging roller 21 to an appropriate amount, and was able to supply the uniform charge promoting particles m.

The charge-promoting particles m applied to the outer surface of the charging roller 21 in a regulated amount by the charge-promoting-particle supply device 22 are supplied to the contact portion between the charging roller 21 and the photosensitive drum 1 by the subsequent rotation of the charging roller 21. Thus, a sufficient amount of the charge-promoting particles m is always uniformly present in each part of the charging nip N.

The non-rotating fixed fur brush 22g also has the effect of preventing the charge promoting particles m from scattering.

<Embodiment 4> (FIG. 5) In the present embodiment, the positions of the non-rotating fixed fur brush 22g and the stirring member 22h in the housing container 22b in the charge accelerating particle supply device 22 of the above-described Embodiment 3 are changed. This is changed to an inverted arrangement as shown in FIG. That is, in the housing container 22b, the stirring member 22h is disposed on the upstream side in the charging roller rotation direction, and the non-rotating fixed fur brush 22g is disposed on the downstream side in the charging roller rotation direction.

In the case of this embodiment, the rotating charging roller 21 receives the adhesion of the charging promoting particles m by the rotating stirring member 22h in the charging promoting particle supply device 22, and then slides by the non-rotating fixed fur brush 22g. The outer peripheral surface is refreshed by being rubbed. And the regulating member 22a
It was possible to regulate the amount of the charge promoting particles m excessively applied to the charging roller 21 to an appropriate amount and supply uniform charge promoting particles m.

The charge-promoting particles m applied to the outer surface of the charging roller 21 in an appropriate amount by the charge-promoting-particle supply device 22 and supplied are supplied to the charging nip between the charging roller 21 and the photosensitive drum 1 by the subsequent rotation of the charging roller 21. Thus, a sufficient amount of the charge-promoting particles m is uniformly present in each portion of the charging nip N at all times.

In the case of this embodiment, since the non-rotating fixed fur brush 22g has a certain ability to regulate the amount of charge-promoting particles, it is disposed at the end of the charge-promoting-particle supply device 22 on the downstream side in the rotation direction of the charging roller. Thus, the regulation member 22a could be omitted.

<Embodiment 5> (FIG. 6) In the present embodiment, the stirring member 22h is omitted and the non-rotating fixed fur brush 22g is attached to the length of the charging roller 21 in the charging-promoting particle supply device 22 of Embodiment 3 described above. The fur brush 22g is oscillated in the longitudinal direction of the charging roller 21 by a fur brush oscillating means (for example, an electromagnetic solenoid mechanism or a crank mechanism) (not shown) when the charging roller 21 is driven to rotate. It is made to exercise.

In the case of this embodiment, the rotating charging roller 21 is
Is rubbed by the oscillating fur brush 22g which oscillates in the longitudinal direction, thereby refreshing the outer peripheral surface more effectively and promoting the circulating supply of the charge accelerating particles m. Then, the regulating member 22a regulated the charge promoting particles m excessively applied to the charging roller 21 to an appropriate amount, and was able to supply the uniform charge promoting particles m.

The charge accelerating particles m, which are applied and supplied to the outer surface of the charging roller 21 in an appropriate amount by the charge accelerating particle supplier 22, are charged by the subsequent rotation of the charging roller 21 so that the charging nip portion between the charging roller 21 and the photosensitive drum 1 is formed. Thus, a sufficient amount of the charge-promoting particles m is uniformly present in each portion of the charging nip N at all times.

In the case of this embodiment, the oscillating fur brush 22
Since g has a certain ability to regulate the amount of charge-promoting particles, it was possible to omit the regulating member 22a by disposing the charge-promoting-particle supply device 22 at the end on the downstream side in the rotation direction of the charging roller.

<Comparative Example 1> (FIGS. 1 and 7) In the printer (FIG. 1 and FIG. 2) of the first embodiment, the charge-promoting particle supply device 22 for the charging roller 21 of the charging device 2 as shown in FIG. , Without the fur brush roller 22c. That is, the charge accelerating particle supplier 22
The housing container 22b, the regulating member 22a, the sealing sheet 22d, and the charge accelerating particles m contained in the housing container 22b.

The other configuration is the same as that of the printer of the first embodiment.

Although the charge accelerating particle supply device 22 as shown in FIG. 7 supplies the charge accelerating particles m to the rotating charging roller 21, considering the supply capability of the charge accelerating particles m, the positive brush by the fur brush actively promotes the charging. Since it does not have a particle application supply step or a refresh step of the outer surface of the charging roller, there is a problem in terms of stabilization of supply and the like.

<Comparative Example 2> (FIGS. 3 and 7) In the cleanerless printer (FIG. 3) of the second embodiment,
As shown in FIG. 7, the fur brush roller 2 is used for the charge accelerating particle supply device 22 for the charging roller 21 of the charging device 2.
2c is omitted. That is, the charge-promoting particle supply device 22 is composed of the housing container 22b, the regulating member 22a, the sealing sheet 22d, and the charge-promoting particles m contained in the housing container 22b.

Other configurations are the same as those of the cleanerless printer of the second embodiment.

As described in Comparative Example 1, although the charging promoting particles m are supplied to the rotating charging roller 21 by the charging promoting particle supply device 22 as shown in FIG. 7, the supply capability of the charging promoting particles m is taken into consideration. Since it does not have a positive brush application / feeding process by the fur brush or a refreshing process of the outer surface of the charging roller, there is a problem in stabilizing the feeding.

<Evaluation> The effectiveness of each of the printers of Examples 1 to 5 and Comparative Examples 1 and 2 was evaluated.
The results are summarized in Table 1.

[0176]

[Table 1] a) Evaluation of Charging Characteristics In each of the printers, charging performance was evaluated based on deterioration of a ghost image.

Since the printer of each example performs image recording by the reversal development system, the ghost means a portion of the photosensitive drum 1 where the image is exposed (also a toner image portion) in the first rotation. This means that a shortage of charging occurs in the second rotation of the drum, so that the previous image pattern on the photosensitive drum is more strongly developed, and a ghost image is generated.

Here, the image evaluation was performed based on the following criteria. In these evaluations, one solid black image was printed on the entire surface, and then the next image continuously output was evaluated as follows.

X: Ghost is observed in a white background after solid black.

：: No ghost is observed in the white background after solid black, but a slight ghost pattern is observed in the halftone portion.

A: No ghost is observed in any of the white background area after the solid black and the halftone area.

The evaluation was performed at the beginning of printing and after printing of 300 sheets (A4 vertical direction).

A printing test was performed using a pattern having a printing ratio of 5% for the image pattern and no difference in the printing ratio in the longitudinal direction.

B) Advantages of Examples 1 to 5 In the printer of Comparative Example 1, although the charge accelerating particles m are supplied to the charging roller 21, the circulation of the charge accelerating particles is poor and an appropriate amount of the charge accelerating particles cannot be secured, so that a ghost occurs in the halftone portion. Was. When the durability was further continued, a bad circulation of toner mixing and charging failure occurred, and charging performance was greatly deteriorated. Even if the cleaner 6 was provided, the charging performance of the charging roller 21 could not be maintained.

[0185] In the printer of Comparative Example 2, since the cleaner is not used, the toner is frequently mixed into the charging roller 21, and the charging property is further reduced. Further, the patterned toner as the transfer residue on the photosensitive drum 1 is transferred to the charging roller 21 and stripped off. However, the non-patterned toner does not form a pattern, and a pattern-like charging failure occurs.

[0186] On the other hand, in the printer of the first embodiment, good charging characteristics are obtained by appropriately applying and supplying the charging promoting particles m to the charging roller 21 by the charging promoting particle supply device 22.

[0187] Also, in the cleaner-less printer of the second embodiment, the toner is mixed into the charging device, and the charging performance is reduced. Although the toner is mixed in the charge accelerating particles m spooled in the housing container 22b of the charge accelerating particle supplier 22, toner contamination of the charge accelerating particle supplier 22 is suppressed to a low level due to effects such as optimizing the charge of the toner. I was able to. As a result, toner can be recycled while maintaining the performance of direct charging. In addition, there was no pattern-like charging failure that occurred due to transfer of the transfer residual toner to the charging roller, which was seen in the printer of Comparative Example 2, and the fur brush 22c refreshed the charging roller 21. You can see that there is.

[0188] Also in the printer of the third embodiment, the refreshing on the charging roller 21 is performed by the fur brush 22g, so that the replacement of the charge promoting particles and the stirring of the toner can be performed. Further, the charge promoting particles m are adhered and applied by the stirring member 22h. As a result, the charging performance could be maintained.

[0189] In the printer according to the fourth embodiment, the charge accelerating particles m are first stirred by the stirring member 22h to cause the charge accelerating particles m to adhere to the charging roller 21, and then, the fur brush 22g is used to refresh the charging roller together with the adhered charge accelerating particles m. Although the charging performance was slightly reduced, the system could operate stably, but no deterioration in charging performance was observed.

[0190] In the printer of the fifth embodiment, the agitation fur brush 22g agitates the charge-promoting particles m, refreshes the charging roller 21, and attaches and supplies the charge-promoting particles m to the charging roller 21. Similar charging performance was maintained.

<Others> 1) The configuration of the charging roller 21 as a flexible contact charging member is not limited to the configuration of the charging roller of the embodiment . Off Eruto, the things of the material and shape of the cloth are stacked,
It is also possible to obtain more appropriate elasticity and conductivity.

It is preferable that the contact charging member is previously coated with charge promoting particles.

2) Contact charging member 21 and developing sleeve 3a
When an AC voltage (alternating voltage) is included in the applied bias with respect to, the waveform of the AC voltage is a sine wave,
A rectangular wave, a triangular wave, or the like can be used as appropriate. Alternatively, a rectangular wave formed by periodically turning on / off a DC power supply may be used. As described above, a bias whose voltage value periodically changes can be used as the waveform of the alternating voltage.

3) The image exposing means for forming an electrostatic latent image is not limited to the laser scanning exposing means for forming a digital latent image as in the embodiment, but may be a normal analog image. Other light-emitting elements such as exposure and LED may be used, and any device that can form an electrostatic latent image corresponding to image information, such as a combination of a light-emitting device such as a fluorescent lamp and a liquid crystal shutter, may be used.

4) A charge injection layer may be provided on the surface of a photoreceptor as an image carrier (charged member) to adjust the resistance of the surface of the photoreceptor.

FIG. 8 is a schematic diagram of the layer structure of the photosensitive member 1 having the charge injection layer 16 on the surface. That is, the photoreceptor 1 has an undercoat layer 12 on an aluminum drum base (Al drum base) 11,
Positive charge injection prevention layer 13, charge generation layer 14, charge transport layer 1
The charge performance is improved by applying the charge injection layer 16 to a general organic photoreceptor coated in the order of No. 5.

The charge injection layer 16 is made of a photo-curable acrylic resin as a binder and conductive particles (conductive filler).
SnO ₂ ultrafine particles 16a (having a diameter of about 0.03 μm
m) A film is formed by mixing and dispersing a lubricant such as tetrafluoroethylene resin (trade name: Teflon), a polymerization initiator, and the like, coating the mixture, and then performing photo-curing.

An important point for the charge injection layer 16 is the resistance of the surface layer. In the charging method by direct injection of electric charges, the electric charges can be transferred more efficiently by lowering the resistance of the object to be charged. On the other hand, when used as a photoconductor, it is necessary to hold the electrostatic latent image for a certain time,
The volume resistance value of the charge injection layer 16 is 1 × 10 ⁹ to 1 ×.
A range of 10 ¹⁴ (Ω · cm) is appropriate.

[0199] Even when not using a charge injection layer 16 as in this configuration, for example, the charge transport layer 15 when Ru Ah in the resistance range similar effect can be obtained.

Further, the volume resistance of the surface layer is about 10 ¹³ Ωcm
A similar effect can be obtained by using an amorphous silicon photosensitive member or the like.

5) The image carrier may be an electrostatic recording dielectric or the like. In this case, after the dielectric surface is uniformly charged to a predetermined polarity and potential, the charge is selectively removed by a charge removing means such as a charge removing needle head or an electron gun to write and form a desired electrostatic latent image.

6) In the embodiment, the developing means 3 is described as an example of a reversal developing device using a one-component magnetic toner. However, the structure of the developing device is not particularly limited. A regular developing device may be used.

7) The recording medium to which the toner image is transferred from the image carrier may be an intermediate transfer body such as a transfer drum.

8) An example of a method for measuring the toner particle size will be described. As a measuring device, Coulter Counter TA-2
Interface (manufactured by Nikkaki) and CX that output the number average distribution and volume average distribution using a mold (manufactured by Coulter)
-1 Connect a personal computer (Canon),
As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride.

The measuring method is as follows.
A surfactant as a dispersant in 150 ml, preferably
0.1 to 5 ml of an alkylbenzene sulfonate is added, and 0.5 to 50 mg of a measurement sample is further added.

The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the particle size of 2 to 40 μm was measured using the Coulter Counter TA-2 using a 100 μ aperture as an aperture. The distribution is measured to determine the volume average distribution. The volume average particle size is obtained from the obtained volume average distribution.

[0207]

As described above, according to the present invention, even when a simple member such as a charging roller is used as the contact charging member, and regardless of the contamination of the contact charging member, the charging of the contact charging member can be performed. The applied bias required is a voltage equivalent to the charging potential required for the member to be charged, and a stable and safe contact charging device that does not use discharge phenomena, that is, low applied voltage, ozone-less, excellent charging uniformity, and long term Therefore, a direct charging device having stable performance can be realized with a simple configuration.

Further, with the simple means configuration, the charge-promoting particles can be stably supplied to the contact charging member without any harm caused by scattering of the charge-promoting particles.

By using this charging device as a charging means for the image carrier, a contact charging type image recording device, a contact charging type / transfer type image recording device, and a contact charging type / transfer type / toner recycling system The image recording apparatus of the above uses a simple member such as a charging roller or a fur brush as a contact charging member, and has a problem of low voltage ozone-less direct charging and a toner recycling system regardless of toner contamination of the contact charging member. It is possible to maintain high-quality image formation for a long period of time, and to maintain high-quality image formation for a long time even after outputting an image with a high image ratio.

[Brief description of the drawings]

FIG. 1 is a schematic configuration model diagram of an image recording apparatus according to a first embodiment.

FIG. 2 is an enlarged cross-sectional model diagram of a contact charging device portion.

FIG. 3 is a schematic configuration diagram of an image recording apparatus (cleanerless) according to a second embodiment.

FIG. 4 is an enlarged schematic cross-sectional view of a portion of a contact charging device of an image recording apparatus according to a third embodiment.

FIG. 5 is an enlarged cross-sectional model view of a contact charging device portion of the image recording device of Embodiment 4.

FIG. 6 is an enlarged cross-sectional model view of a contact charging device portion of the image recording apparatus according to the fifth embodiment.

FIG. 7 is an enlarged cross-sectional model diagram of a contact charging device portion of the image recording devices of Comparative Examples 1 and 2.

FIG. 8 is a schematic diagram illustrating a layer configuration of an example of a photoconductor provided with a charge injection layer on a surface.

FIG. 9 is a graph showing charging characteristics.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum (image carrier, charged object) 2 contact charging device 21 charging roller (contact charging member) 22 charge promoting particle supply device 22 a regulating member 22 b housing 22 c fur brush roller 22 d sealing sheet 22 g fixed fur brush or swing fur Brush 22h Stirring member m Charge accelerating particles 3 Developing device 4 Transfer roller 5 Fixing device 6 Cleaning device (cleaner) 7 Laser beam scanner (exposure device) S1 to S3 Bias power supply

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-190046 (JP, A) JP-A-7-36322 (JP, A) JP-A-9-160461 (JP, A) JP-A-6-160461 348106 (JP, A) JP-A-11-45011 (JP, A) JP-A-6-274010 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/02 G03G 15 / 16 103

Claims (20)

(57) [Claims] 1. A charging method for charging a surface of an object to be charged by a flexible charging member forming a nip portion with the object to be charged. member comprises a foam on its surface, charging accelerating the surface of the charging member by supplying a surface charge enhancing particles of the charging member by rubbing the surface of the charging member
Charging method characterized by have a fur brush to refresh the particles. 2. The charge-promoting particles have a volume resistance of 10 ¹² Ω ·
2. The charging method according to claim 1, wherein the charging method is not more than cm. 3. The charge-promoting particles have a volume resistance of 10 ¹⁰ Ω ·
2. The charging method according to claim 1, wherein the charging method is not more than cm. 4. The charging method according to claim 1, wherein the charging member is a rotating member, and is driven with a speed difference with respect to the member to be charged, and a voltage is applied. . 5. The charging device according to claim 1, wherein the fur brush in contact with the charging member has a shape of a fur brush roller in which fibers spread radially, and is driven to rotate. Method. 6. The fur brush according to claim 1, wherein the fur brush in contact with the charging member is free to swing in the longitudinal direction of the charging member, and has a means for swinging the fur brush. The charging method described in the above. 7. The charging method according to claim 1, wherein a stirrer for stirring the charge-promoting particles is provided in a housing of the charge-promoting particle supplier. 8. A charging device according to claim 1, further comprising a regulating means for regulating, in the rotating direction of the charging member, the charge promoting particles excessively supplied to the charging member after the fur brush. The charging method according to one of the above. 9. A charging device for charging a surface of an object to be charged by a flexible charging member forming a nip portion with the object to be charged. member comprises a foam on its surface, charging accelerating the surface of the charging member by supplying a surface charge enhancing particles of the charging member by rubbing the surface of the charging member
A charging device, characterized in that it have a fur brush to refresh the particles. 10. The charge accelerating particles have a volume resistance of 10 ¹² Ω.
The charging device according to claim 9, wherein the charging device is equal to or less than cm. 11. The volume resistivity of the charge accelerating particles is 10 ¹⁰ Ω.
The charging device according to claim 9, wherein the charging device is equal to or less than cm. 12. The charging device according to claim 9, wherein the charging member is a rotary member, and is driven with a speed difference with respect to the member to be charged, and a voltage is applied. . 13. The fur brush in contact with the charging member has a shape of a fur brush roller in which fibers spread radially,
The charging device according to any one of claims 9 to 12, wherein the charging device is driven to rotate. 14. A fur brush in contact with the charging member is free to swing in the longitudinal direction of the charging member, and has means for swinging the fur brush.
The charging device according to any one of the above. 15. The charging device according to claim 9, wherein a stirrer for stirring the charge-promoting particles is disposed in a housing of the charge-promoting-particle supply device. 16. A charging device according to claim 9, further comprising a regulating means for regulating a charge-promoting particle excessively supplied to the charging member after the fur brush in a rotating direction of the charging member. The charging device according to one of the preceding claims . 17. An image recording apparatus for performing image recording by applying an image forming process including a step of charging the image carrier to the image carrier, wherein the step of charging the image carrier is performed. An image recording apparatus, which is the charging device according to any one of Items 1 to 16. 18. A image bearing member, a charging means for charging the image bearing member, a latent image for forming an electrostatic latent image on the charged surface of the image bearing member
Forming means , developing means for visualizing the electrostatic latent image with a developer, transfer means for transferring the developer image to a recording medium,
Having a cleaning means for cleaning the image carrier after transfer,
17. An image recording apparatus wherein an image carrier is repeatedly used for image formation, and a charging unit for charging the image carrier is the charging device according to any one of claims 9 to 16. Recording device. 19. A image bearing member, a charging means for charging the image bearing member, a latent image for forming an electrostatic latent image on the charged surface of the image bearing member
Forming means , developing means for visualizing the electrostatic latent image with a developer, and transfer means for transferring the developer image to a recording medium, wherein the developing means transfers the developer image to the recording medium. The cleaning device also serves as a cleaning unit that collects the developer remaining on the image carrier after the image forming apparatus, wherein the image carrier is an image recording apparatus that is repeatedly provided for image formation, and a charging unit that charges the image carrier is claimed. An image recording apparatus, which is the charging device according to any one of 9 to 16. 20. The image recording apparatus according to claim 18, wherein the information writing means for forming an electrostatic latent image on the charged surface of the image carrier is an image exposure means.