JP2000356932A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable improvement in image quality and increase in the life of an image carrier by, in the case that more discharge products are produced than that by a monochrome image forming device, removing the discharge products. SOLUTION: A photocatalyst substance 50 capable of decomposing discharge products such as ozone and NOx produced by discharge is applied to the casing 31 of an electrifying device 30 which discharges a photoreceptor drum. The photocatalyst substance 50 is excited by light emitted during the discharge and the discharge products are thereby removed. This prevents an image flow caused by a film of nitric acid or nitrate due to NOx and eliminates the need for mechanical sliding and rubbing against the surface of the photoreceptor drum for the removal of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
The present invention relates to a color image forming apparatus including a discharging unit for discharging a discharge target.

[0002]

2. Description of the Related Art Conventionally, as a color image forming apparatus of this type, a photoconductor, which is a latent image carrier having a photoconductive substance, is uniformly charged by a charging device, and the photoconductor is exposed to an image to form an electrostatic image. Forming a latent image, developing it with a developer, and finally transferring it to a recording material such as paper, and then fixing the toner image transferred on the paper using heat, pressure, etc., to form a color image It is known to do. In such a color image forming apparatus, as a uniform charging means for uniformly charging the photosensitive member, there is an apparatus using a discharging means utilizing a discharge such as corona discharge. Further, as a transfer unit for transferring a toner image formed on an image carrier such as a latent image carrier or an intermediate transfer body to a transfer material such as paper or an intermediate transfer body, there is a transfer unit using the discharge unit. In the discharge performed by such a discharge means, nitrogen oxide (hereinafter, “NOx”) is used.
That. ) And ozone and other discharge products.

[0003] Of these discharge products, NOx reacts with moisture in the air or the like to produce nitric acid, and reacts with metals to produce metal nitrates. When the thus generated nitric acid or nitrate is formed as a thin film on the surface of the image bearing member, the resistance value of the surface of the image bearing member decreases due to the hygroscopic action of the nitric acid or nitrate. Thereby, the electrostatic latent image formed on the photosensitive drum serving as the image carrier is destroyed,
There is a problem that the quality of the formed image is deteriorated. In particular, in a high-humidity environment, an abnormal image such as a flowing image is generated.

On the other hand, among the above-mentioned discharge products, ozone has a problem that the stability of discharge is significantly reduced. Further, this ozone has a problem that it has a strong ability to oxidize a partner substance, adheres to an image carrier, degrades electrostatic characteristics, and causes deterioration of the quality of a formed image. Further, there is a problem that the environment is deteriorated by the ozone.

[0005] In particular, in a color image forming apparatus for transferring a toner image formed on a latent image carrier onto a transfer material while overlapping one color at a time, when the toner is transferred onto the transfer material in an overlapping manner, the transfer is performed. Since it is necessary to overcome the Coulomb repulsion of the toner image existing on the material, it is necessary to gradually increase the transfer electric field. For this reason, the transfer current generated by the discharging means for forming the transfer electric field gradually increases, and the amount of discharge products generated is larger than in the monochrome image forming apparatus. That is, in such a color image forming apparatus, problems caused by discharge products are greater than in a monochrome image forming apparatus.

Further, each of the latent image carriers for forming a toner image of each color is provided on the recording material while the recording material is conveyed by a transfer belt which is a conveying member for conveying the recording material. In a color image forming apparatus for sequentially transferring the upper toner images, there are a plurality of uniform charging means for uniformly charging each latent image carrier. Further, there are a plurality of transfer means for transferring the toner image from each latent image carrier to the recording material. Further, there are a separation unit for separating the recording material from the conveyance belt after the transfer, and a conveyance member charge elimination unit for discharging the conveyance belt. Therefore, when a discharging means such as a corona charger is used as these means, more discharge products are generated, and the trouble caused by the discharge products becomes larger.

Conventionally, regarding NOx of the above-mentioned discharge products, a nitric acid or nitrate film formed on an image carrier is
The image carrier has been mechanically rubbed and scraped off by a cleaning member such as a blade or a brush which constitutes a cleaning means for collecting transfer residual toner remaining on the image carrier. As a result, the occurrence of an abnormal image due to NOx could be suppressed to some extent. However, when the film on the surface of the image carrier is scraped off by the cleaning member, there is a problem that the life of the image carrier is reduced. Further, in an image carrier having a photoconductive layer on the surface such as a photoconductor, if the layer thickness of the photoconductive layer is too thick,
There is a problem that the diffusion of photocarriers generated at the time of image exposure increases and the resolving power decreases. In this case, there is a disadvantage that the life of the image carrier cannot be extended while maintaining high image quality.

On the other hand, there has been proposed a cleanerless system in which such a cleaning means is not provided, and the transfer residual toner remaining on the latent image carrier is collected by using a developing device or the like. In this cleanerless system, the apparatus can be simplified by the elimination of the cleaning apparatus, and the apparatus can be downsized. Further, in this cleanerless system, since the surface of the latent image carrier is not shaved by a cleaning member such as a blade or a brush, the life of the latent image carrier is extended while maintaining high image quality. Can also. An image forming apparatus to which such a cleanerless system is applied is disclosed in JP-A-11-30898.

However, in an image forming apparatus to which this cleanerless system is applied, there is no cleaning member which has also a function of scraping a nitric acid or nitrate film. Therefore, there is a need to remove such nitric acid or nitrate films by other methods. As a method therefor, a method in which one of a charging device, a developing device, and a transfer device disposed around the latent image carrier has a function of scraping a nitric acid or nitrate film can be considered. But,
In the case of a charging device and a transfer device, a contact-type charging device or a transfer device that presses the latent image carrier with a considerably strong pressing force to scrape the nitric acid or nitrate film must be used. For this reason, there arises a problem that the contact member that comes into contact with the latent image carrier is stained by the toner and the life of the apparatus is shortened. Further, in the case of the developing device, the developing function, whether using one-component developer or two-component developer,
A condition for satisfying both the function of collecting the transfer residual toner and the function of scraping the film on the image carrier is required. But,
There is a problem that setting of the condition is very difficult. Also, in the case of this developing device, there is a problem that the life of the device is shortened.

As a method of removing the nitric acid or nitrate film, a method of providing a new device for scraping the nitric acid or nitrate film on the latent image carrier can be considered. But,
In this method, the mechanism and durability of the device itself become new subjects, and a space corresponding to the new problem is required. Therefore, the result is contrary to the simplification of the device, which is the original purpose of the cleanerless system. Further, in a color image forming apparatus, it is more important than a monochrome image forming apparatus to scrape off a nitric acid or nitrate film formed on the surface of an image carrier, but there is a problem that a collected toner is mixed. In effect, cleanerless systems cannot be employed.

By the way, various methods have been proposed for solving the problems caused by the discharge products by other methods than the method of scraping the surface of the latent image carrier as described above. For example, Japanese Patent Application Laid-Open No. H10-34003 discloses an image forming apparatus that uses a method in which ozone generated by discharge is exhausted to the outside of the apparatus by an exhaust unit to prevent deterioration of charging characteristics due to ozone.
No. 0 discloses this. Also, Japanese Patent Laid-Open No. 5-3032
No. 44 discloses an image forming apparatus which uses a method of providing a dew condensation preventing heating means for preventing dew formation on a photoreceptor, thereby preventing NOx generated by electric discharge from becoming nitric acid. Further, Japanese Patent Application Laid-Open No. Hei 9-114191 discloses a method in which a creeping glow discharge device is juxtaposed on the same substrate of a discharge electrode for charging, and NO generated by discharge is used.
A charging device for decomposing x is disclosed. Furthermore, Japanese Patent Publication No. 8-23715 discloses a corona generating device that absorbs NOx by using a method of coating an alkaline film that neutralizes NOx on a shield or the like that is a constituent member of the corona generating device. I have.

[0012]

As described above, ozone, which is a discharge product, oxidizes the image carrier to cause a problem of deteriorating the quality of a formed image, and NOx causes nitric acid or nitric acid on the image carrier. This causes a problem that the quality of a formed image is deteriorated by forming a nitrate film. Conventionally, various methods for solving these problems have been proposed. However, in the method disclosed in JP-A-10-340030, ozone, which is a discharge product generated by discharge, cannot be completely discharged. Some of them diffused into the apparatus, so that a sufficient effect for solving the problem caused by ozone was not obtained.

In the conventional method for solving the problem caused by NOx, according to the method disclosed in Japanese Patent Application Laid-Open No. Hei 5-303244, since a discharge product generated by the discharge diffuses into the apparatus, nitric acid or nitrate is used. There is a problem that a sufficient effect for preventing the film from being formed on the image carrier cannot be obtained. Further, this publication discloses a configuration utilizing warm air generated by a heater of a fixing unit. However, in this configuration, heat in the developing device easily causes toner in a developing device to aggregate, and this toner is used as a developer carrier. May stick to the In addition, Japanese Patent Application Laid-Open No. 9-141141
The method disclosed in Japanese Patent Publication No. 91 has a disadvantage that the structure of the discharge device is complicated. In addition, the above-mentioned Tokuhei 8-237
In the method of JP-A No. 15 (1995), the alkaline coating is consumed when neutralizing NOx, so that there is a problem that a sufficient life cannot be obtained.

On the other hand, conventionally, the problem of NOx has been solved by scraping off a nitric acid or nitrate film formed on the image carrier with NOx by a cleaning member. There is a problem that the life is shortened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and a first object of the present invention is to provide a color image forming apparatus which generates more discharge products by discharging than a monochrome image forming apparatus. An object of the present invention is to propose a novel color image forming apparatus capable of removing a product and improving the quality of a color image and extending the life of an image carrier. A second object is to propose a color image forming apparatus capable of removing discharge products generated by discharge with a simple configuration.

[0016]

In order to achieve the first object, the invention according to claims 1 to 14 is provided with a discharge means for a discharge object and performs development using a plurality of color developers. In a color image forming apparatus for forming a color image, a discharge product decomposing means having a photocatalyst substance capable of decomposing a discharge product generated by the discharge of the discharge means, and exciting the photocatalytic substance during the discharge Light irradiating means for irradiating the discharge product decomposing means with light having a wavelength component.

In this color image forming apparatus, the discharge products generated in the discharge can be decomposed by the action of the photocatalytic substance. That is, before the NOx, which is the discharge product, reacts with moisture in the air or the like to generate nitric acid, or before reacting with a metal to generate metal nitrate, ozone is oxidized by contact with the image carrier. before,
The NOx and ozone can be removed. Therefore,
The formation of a nitric acid or nitrate film on the image carrier and the oxidation of the image carrier can be prevented in advance.

Further, since a nitric acid or nitrate film can be prevented from being formed on the image carrier in this manner,
It is not necessary to remove this film by a method of mechanically rubbing and scraping the surface of the image carrier as in the related art.

In particular, the invention according to claim 2 is the color image forming apparatus according to claim 1, further comprising developing means for developing the latent image formed on the latent image carrier. The present invention is characterized in that a function as a cleaning means for cleaning the transfer residual toner remaining on the body is added.

In this color image forming apparatus, since a so-called cleaner-less system is adopted, the apparatus can be simplified and the size of the apparatus can be reduced by eliminating the cleaning device as the cleaning means. In addition, in the case of the cleanerless system, the surface of the latent image carrier is not shaved by the cleaning member, so that there is no need to worry about the surface deterioration of the latent image carrier. still,
Since NOx, which is a discharge product, is removed in advance by the photocatalytic substance as described above, it is possible to solve the problem of nitric acid or nitrate due to NOx, which has conventionally been present in a cleanerless system.

The invention according to claim 3 is based on claim 1 or 2
In the above color image forming apparatus, a luminous body is used as the light irradiation means. In this color image forming apparatus, the photocatalytic substance is irradiated with light necessary for exciting the electrons in the photocatalytic substance by the luminous body. Therefore, it is possible to select light having a wavelength most suitable for the photocatalyst substance to be used, to irradiate the photocatalyst substance, and to efficiently decompose a discharge product in the photocatalyst substance.

According to a fourth aspect of the present invention, there is provided a color image forming apparatus according to the first or second aspect, wherein a discharge means for performing discharge with light emission is used as the discharge means. A discharge means is used as the light irradiation means. In this color image forming apparatus, there is no need to provide a member or a device for irradiating light for exciting electrons in the photocatalytic substance.

According to a fifth aspect of the present invention, there is provided the color image forming apparatus of the first, second, third or fourth aspect of the present invention, wherein the component constituting the discharging means is provided with the discharging means. A photocatalytic substance capable of decomposing a discharge product generated by discharge is provided, and the constituent member is used as the discharge product decomposition means. In this color image forming apparatus, there is no need to provide a new member or device as the discharge product decomposing means. In addition, by using the constituent members constituting the discharge means as the discharge product decomposition means, the discharge products can be quickly and efficiently removed.

[0024] In particular, the invention according to claim 6 is the discharge device, wherein the discharge means includes a discharge electrode, and a casing surrounding the discharge electrode and having an opening for performing the discharge to a discharge target. 5. The color image forming apparatus according to claim 5, wherein the constituent member is the casing. In this color image forming apparatus, since the casing of a discharge device such as a corona discharge device has a photocatalytic substance, the discharge product can be quickly removed in the casing. Therefore, the discharge product can be removed before the discharge product flows out of the casing, and the influence of the discharge product on devices and members outside the discharge device is further reduced. be able to.

According to a seventh aspect of the present invention, there is provided a discharge apparatus in which the discharge means includes a discharge electrode and a casing surrounding the discharge electrode and having an opening for discharging the discharge to a discharge target. 7. The color image forming apparatus according to claim 5, wherein said constituent member is said discharge electrode. In this color image forming apparatus, since the discharge electrode of the discharge device has a photocatalytic substance, the discharge products can be quickly and efficiently removed. Therefore, the discharge product can be removed before the discharge product flows out of the casing, and the influence of the discharge product on devices and members outside the discharge device is further reduced. be able to.

According to an eighth aspect of the present invention, the discharge means has a discharge electrode and an opening surrounding the discharge electrode for performing the discharge to a discharge object, and a grid is provided in the opening. 8. The color image forming apparatus according to claim 5, 6 or 7, wherein the component is the grid. In this color image forming apparatus, a discharge device having a grid at an opening such as a scorotron type discharge device is used, and since the grid has a photocatalytic substance,
The discharge products can be quickly and efficiently removed. Therefore, the discharge product can be efficiently removed before the discharge product flows out of the casing, and the influence of the discharge product on devices and members outside the discharge device is further reduced. Can be reduced.

According to a ninth aspect of the present invention, there is provided the image forming apparatus according to the fifth, sixth or fifth aspect, further comprising a uniform charging means for uniformly charging the latent image carrier.
In the color image forming apparatus of the seventh or eighth aspect, the discharging means is the uniform charging means. As described above, the discharge products have an adverse effect on the image carrier, and cause deterioration in the quality of the formed image. Therefore, a device that involves a discharge in the vicinity of the image carrier has the most adverse effect on the image carrier and degrades the quality of image formation. Therefore, in the color image forming apparatus according to the present invention, a photocatalytic substance is provided to a component constituting a uniform charging unit facing a latent image carrier such as a photoreceptor as an image carrier, and the image carrier is provided to the image carrier. By removing a portion of the discharge product that is most likely to have an adverse effect, the adverse effect can be efficiently reduced.

According to a tenth aspect of the present invention, there is provided the color image forming apparatus according to the fifth, sixth, seventh, eighth, or ninth aspect, further comprising a charge eliminator for transferring the toner image on the image carrier after the transfer. In the apparatus, the discharging means is the discharging means. In this color image forming apparatus, a photocatalyst substance is provided to a component constituting a static eliminator facing an image carrier such as a photoreceptor or an intermediate transfer body, and a portion which is most likely to have the most adverse effect on the image carrier is provided By removing the discharge products, the adverse effects can be efficiently reduced.

According to the eleventh aspect of the present invention, there is provided the color image forming apparatus according to the fifth, sixth, seventh, eighth, ninth or tenth aspect, further comprising a transfer means for transferring the toner image formed on the image carrier to a transfer material. In the apparatus, the discharge means is the transfer means. Not only the device with a discharge close to the image carrier, but also a device with a discharge away from the image carrier, the discharge products generated by the discharge are dispersed in the machine and the image carrier Will have an adverse effect. Therefore, in the color image forming apparatus according to the present invention, a photocatalyst substance is provided to a component constituting a transfer unit, and a discharge product in a portion that may adversely affect the image carrier is removed. The adverse effects can be reduced.

The invention according to claim 12 is provided with a separating means for separating the recording material from a conveying member for conveying the recording material after transferring the toner image formed on the image carrier onto the recording material. The color image forming apparatus according to claim 5, 6, 7, 8, 9, 10, or 11, wherein the discharging means is the transfer means. In this color image forming apparatus, it is possible to reduce the adverse effect by applying a photocatalytic substance to a constituent member constituting the separating unit and removing a discharge product in a portion that may adversely affect the image carrier. it can.

According to a thirteenth aspect of the present invention, there is provided a conveying member discharging means for discharging a toner image formed on an image carrier onto a recording material conveyed by the conveying member, and thereafter discharging the conveying member. Claims 5, 6, 7, 8, 9, 1 provided
In the color image forming apparatus of 0, 11 or 12, the discharging means is the conveying member charge removing means. In this color image forming apparatus, a photocatalyst substance is applied to a constituent member of the transfer member static elimination means, and a portion of a discharge product which may have a bad influence on the image carrier is removed to reduce the adverse effect. be able to.

Further, the invention of claim 14 is based on claim 1,
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, wherein the photocatalytic substance is titanium oxide. In this color image forming apparatus, titanium oxide, which is suitable in terms of reaction efficiency with the discharge product, safety, and usable wavelength band, is used as the photocatalytic substance, thereby quickly and efficiently removing the discharge product. be able to.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] Hereinafter, a color electrophotographic copying machine (hereinafter, referred to as a color image forming apparatus) according to the present invention will be described.
Simply called "copier". ) Will be described (hereinafter, this embodiment is referred to as “first embodiment”). First, the configuration of the entire copying machine according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment. The copying machine includes an image reading unit (hereinafter, referred to as “scanner unit”) 1 and an image forming unit (hereinafter, referred to as “printer unit”) 2.

The scanner unit 1 forms an image of an original 4 placed on a contact glass 3 on a CCD 7 via an illumination lamp, a mirror group 5 and a lens 6 (not shown), and converts color image information of the original. For example, each color separation light of Blue (hereinafter, referred to as “B”), Green (hereinafter, referred to as “G”), and Red (hereinafter, referred to as “R”) is read and converted into an electric image signal. . The B, G, and R image signals thus obtained are subjected to color conversion processing by an image processing unit (not shown) based on the intensity levels.
By this color conversion processing, yellow (hereinafter, referred to as "Y"), cyan (hereinafter, referred to as "C"), magenta (hereinafter, referred to as "M"), black (hereinafter, "Bk").
That. ) Is obtained.

In the printer unit 2, the printer unit 1
An image is formed based on the color image data obtained in step (1). In the present embodiment, four photosensitive drums (10Y, 10C, 10M, and 10Bk) are provided as latent image carriers, and the photosensitive drums corresponding to Y, C, M, and Bk are provided from the sheet supply unit 15 side. Are arranged on the same plane. The surface of each of the photosensitive drums (10Y, 10C, 10M, 10Bk) is uniformly charged to a negative polarity by a charging device (11Y, 11C, 11M, 11Bk) provided as a uniform charging means. Is done. In the charging of the present embodiment, a method of generating charges by corona discharge and spraying the photosensitive drum surface is used,
As the charging device, a corotron charging device, a scorotron charging device, or the like can be used.

The photosensitive drums (10Y, 10C, 10M, 10Bk) uniformly charged in this manner are Y, C,
Based on the image data to be developed in each color of M and Bk,
Optical writing corresponding to each image data is performed by optical writing units (12Y, 12C, 12M, 12Bk) provided for each of the photosensitive drums. As a result, the electrostatic latent images formed on the respective photosensitive drums are made to have negative polarity by the developing devices (13Y, 13C, 13M, 13Bk) as developing means provided for the respective photosensitive drums. Reversal development is performed by the charged toner of each color.

Each of the photosensitive drums (1
0Y, 10C, 10M, and 10Bk) are supplied to respective transfer areas formed between the respective photosensitive drums and the transfer unit 20 via the registration rollers 16 from the paper supply unit 15 and fed to the respective transfer areas. The image is transferred onto a recording sheet 100 which is a recording material as a supplied transfer material.

In this transfer, the fed recording paper 10
Numeral 0 is electrostatically attracted to a transfer belt 21 as a transport member stretched by support rollers as a plurality of support members, and is transported as the transfer belt moves. The transfer belt 21 is formed from a dielectric such as a polyester film. Each photoconductor drum (10Y, 10C, 1
0M, 10Bk), and transfer devices (22Y, 22C, 22M, 22Bk) as transfer means disposed on the back side of the transfer belt 21 so as to face the respective photosensitive drums. Is superimposed and transferred onto the recording paper 100. Specifically, each transfer device (22Y, 22C, 22M, 22Bk)
As a result, the transfer belt 21 is positively charged, so that the negatively charged toner on each photosensitive drum is attracted to the transfer belt side by electrostatic force, and the recording paper 100
Is transferred to

The recording paper 100 on which the toner images of each color have been transferred is provided so as to face the surface of the transfer belt 21, and is provided as a separating unit disposed at an end of the fixing device 26 as a fixing unit. The transfer belt is separated from the transfer belt by a separation device 23. The separating device 23 performs a negative AC corona discharge from the upper surface of the recording paper 100 conveyed by the transfer belt 21, that is, the surface on which the toner image is transferred. Thereby, the recording paper 1
The electric charge accumulated in the recording paper is neutralized by removing the electric charge, thereby preventing toner dust due to peeling discharge generated when the recording paper is separated from the transfer belt.

The recording paper 100 separated from the transfer belt 21 in this way enters the fixing device 26, and a color image is obtained by fixing the toner image on the recording paper. After the recording paper 100 is separated,
The transfer belt 21 is neutralized by a belt static eliminator 24 as a conveying member static eliminator and is initialized. The belt static eliminator 24 performs a negative AC corona discharge from both sides of the transfer belt 21 to neutralize and neutralize accumulated charges on the transfer belt. Then, the transfer belt 21 from which the charge has been removed in this manner is cleaned by a cleaning unit 25 as a cleaning unit to remove residual toner remaining on the transfer belt.

After the transfer, each photosensitive drum (10Y, 10Y,
The transfer residual toner remaining on the photoconductor drums 10C, 10M, and 10Bk) is a cleaning device (14Y, 14C, 14C) as a cleaning unit provided for each photosensitive drum.
M, 14Bk). The cleaning device is provided with a cleaning blade as a cleaning member, and the cleaning blade cleans the surface of the photosensitive drum by scraping off the transfer residual toner on the photosensitive drum. Then, the cleaned photosensitive drums (10Y, 10C, 10M,
10Bk) is the charging device (11Y, 11C, 11
M, 11Bk), the surface is uniformly charged again, and the process proceeds to the next image forming step.

Next, the charging device (11Y, 11C, 11M, 11Bk) and the transfer device (2
2Y, 22C, 22M, and 22Bk), a configuration of a discharge device as a discharge unit used as the separation device 23 and the belt static elimination device 24 will be described. As these devices, a corotron type or scorotron type discharge device or the like can be used.

FIG. 2 is a schematic structural view of a corotron discharge device. The corotron discharge device 30 includes a casing 31 having a rectangular or cylindrical opening opening toward a discharge target, a discharge wire 32 serving as a discharge electrode disposed near a center inside the casing, And a high voltage power supply 33 for applying a predetermined high voltage to the power supply. In the corotron discharge device 30, when the high-voltage power supply 33 applies a voltage to the discharge wire 32, a corona discharge is generated in the discharge wire. The casing 31 is formed of a metal such as aluminum or stainless steel, and shields portions other than the opening toward the discharge target. Thereby, the discharge stability of the corotron discharge device 30 is improved. In addition, as the discharge wire 32, for example, tungsten can be used.

FIG. 3 is a schematic structural view of a scorotron discharge device. Like the corotron discharge device 30, the scorotron discharge device 40 also has a casing 41 having a square or cylindrical opening opening toward the discharge target, and a discharge wire disposed near the center of the inside of the casing. And a high-voltage power supply 43 for applying a predetermined high voltage to the discharge wire. However, the scorotron discharge device 40 differs from the corotron discharge device 30 in that a grid 44 is provided at the opening. A predetermined voltage is applied to the grid 44 from a varistor 45. The materials and the like of the casing 41 and the discharge wire 42 are the same as those of the corotron discharge device 30 described above. This scorotron discharge device 40
Can control the ion flow due to the corona discharge generated in the discharge wire 42 by the grid 44, prevent the discharge unevenness, and control the potential of the discharge target.

Such a discharge device used in this embodiment has at least one of its constituent members
A photocatalytic substance 50 capable of decomposing discharge products such as ozone and NOx generated by the discharge is provided. The photocatalyst substance 50, when irradiated with light, emits ozone or N which is a discharge product generated by the discharge.
It has an action of decomposing these when contacted with Ox.
As the photocatalyst substance 50, a semiconductor substance such as TiO ₂ can be used.

Since the photocatalytic substance 50 is used to decompose a discharge product generated by the discharge generated at the discharge electrode of the above-described discharge device, it is preferable to arrange the photocatalyst substance 50 in a region close to the discharge electrode. Specifically, when a corotron discharge device 30 is applied as the discharge device, the photocatalytic substance is preferably applied to at least the surface of the casing 31 facing the discharge wire 32. When the scorotron discharge device 40 is applied as the discharge device, the photocatalytic substance is preferably applied to at least the surface of the casing 41 and the surface of the grid 44 facing the discharge wire 42. In addition, discharge wires (32, 4) for generating discharge
The above photocatalytic substance may be mixed in the material of 2). According to this configuration, the discharge products can be more efficiently removed.

In this embodiment, the charging device (11)
Y, 11C, 11M, 11Bk) and a transfer device (22
Y, 22C, 22M, and 22Bk), the corotron discharge device 30 or the scorotron discharge device 40 is used, and the constituent members of at least one of these devices are used as discharge product removing means. A corotron discharge device 30 is used as the separation device 23 and the belt static elimination device 24. Note that the present invention is not limited to these discharge devices.

Next, the function of the photocatalytic substance will be described. When a semiconductor material such as TiO ₂ used in the present embodiment is irradiated with light having a wavelength corresponding to the band gap of the material, electrons existing in the valence band are excited to the conduction band and the valence band is excited. Holes are generated in the electron band. The excited electrons in the semiconductor material become free electrons and become movable. For example, when the semiconductor material is in contact with a metal, the excited electrons flow from the valence band into the metal. Has a reducing effect on Similarly, by irradiating the semiconductor substance with light having an appropriate wavelength, the excited electrons are reduced by ozone or NOx by their reducing action.
Is reductively decomposed.

As the photocatalytic substance 50 for reducing and decomposing ozone and NOx, in addition to the above-mentioned TiO ₂ ,
O ₃ , ZnO, CdS, or the like can also be used. Among them, anatase TiO ₂ is particularly preferable from the viewpoint of reaction efficiency, safety, and usable wavelength band. As the photocatalyst substance 50, the substances exemplified above may be used alone, but two or more of these substances may be mixed, or Pt, Pd, Rh, Nb or the like may be mixed with these substances. By using such a substance, the photocatalysis can be further promoted.

As a method of applying the photocatalyst substance 50 to the components of the above-described discharge device, a chemical vapor deposition method, neutralization or hydrolysis of an inorganic metal salt, hydrolysis of a metal alkoxide, a sol-gel method, or the like is used. be able to. By using these methods,
Casing (31, 41) and discharge wire (32, 4)
2) In the case of a scorotron discharge device, grid 44
Can be formed directly or partially on the entire surface.

Further, a film made of the photocatalytic substance 50 may be formed on a substrate separate from these constituent members, and the substrate may be bonded to the casing (31, 41) or the grid 44. Further, a commercially available photocatalyst fine powder may be adhered to the casing (31, 41), the discharge wires (32, 42), and the grid 44. Furthermore, by using a material in which the photocatalytic substance is mixed in the material as the above-mentioned constituent member, the constituent member itself can have the reducing action of the photocatalytic substance.

In the case of a structure in which a photocatalytic substance is given to the constituent members of the discharge device as in this embodiment, the casing (31, 4) is used.
The discharge products can be decomposed inside 1).
Therefore, the discharge product can be removed before the discharge product comes into contact with a member such as the photosensitive drum 10 outside the discharge device or another device. As a result, it is possible to prevent adverse effects of the discharge products on these members and devices. In the present embodiment, the configuration in which the photocatalyst substance is provided to the constituent members of the discharge device that performs the discharge as described above is described. However, instead of providing to such a constituent member, other members provided with the photocatalytic substance are provided. May be provided separately. In addition, it is preferable that such a member is disposed close to a device that performs discharge.

As described above, such a photocatalytic substance cannot decompose a discharge product unless irradiated with light having a wavelength component at which valence band electrons in the photocatalytic substance are excited to the conduction band. . Therefore, light irradiating means for irradiating light to the constituent member provided with the photocatalytic substance is required. In the present embodiment, a discharge device that performs corona discharge with light emission close to purple is used, and ultraviolet light is also emitted in this corona discharge. Therefore, in the present embodiment, this ultraviolet light is used as light irradiation means. With this configuration, when corona discharge occurs in the discharge device, ultraviolet rays are radiated by the discharge, and electrons in the photocatalytic substance 50 given to the components of the discharge device are excited. The discharge product is decomposed by the action of the excited electrons.

In the present embodiment, ultraviolet light emitted during corona discharge is used as the light irradiation means. However, as another configuration example, as shown in FIG. 4, light applicable to the photocatalytic substance is emitted. A lamp 34 which is a light emitter as a light irradiating means may be separately provided. In FIG. 4, the lamp 34 is arranged inside the casing 31. However, the lamp does not necessarily need to be inside the casing, but may be arranged outside the casing. In this case, since the electric field distribution inside the casing 31 is not disturbed by the lamp 34, the discharge wire 3
2 can be stabilized. Further, by arranging the lamp 34 outside the casing 31 in this manner, restrictions on the size and shape of the lamp are relaxed, and cost reduction can be achieved.

When the n-type semiconductor TiO ₂ is used as the photocatalyst, for example, a lamp that emits light having a wavelength of 400 nm or less can be used as the lamp 34. As such a lamp 34, an ordinary fluorescent lamp, halogen lamp, ultraviolet lamp, or the like can be used. In particular, a higher effect can be obtained by using an ultraviolet lamp. When the surface of the luminous body is coated with an n-type semiconductor photocatalytic substance,
The photocatalytic substance coated on the luminous body can also decompose the discharge product that has come into contact with the luminous body.
When such a luminous body is used, the wavelength of light to be applied to the photocatalytic substance can be selected by appropriately selecting the luminous body to be used. Wavelength light can be selected.

As described above, in the present embodiment, when the photocatalyst substance 50 provided to the components of the discharge device is irradiated with light by corona discharge generated in the discharge device, the photocatalyst material is activated to perform a reducing action. It can decompose discharge products such as ozone and NOx. Therefore, a charging device (11Y, 11C, 11C) to which such a discharging device is applied.
M, 11Bk), transfer devices (22Y, 22C, 22M,
22Bk), the discharge products generated in the casings (31, 41) of the separation device 23 and the belt neutralization device 24 are efficiently discharged by the photocatalytic substance 50 in the casing before flowing out of the casing to the outside. Is decomposed into

As a result, ozone, which is a discharge product, is transferred to, for example, the photosensitive drum (10Y, 10C, 10M, 1).
0Bk) It is possible to prevent problems such as deterioration of the quality of the formed image by oxidizing the surface and leakage to the outside of the copying machine to deteriorate the environment. Further, nitric acid or nitrate by NOx which is a discharge product is transferred to the photosensitive drum (1).
0Y, 10C, 10M, and 10Bk), and can prevent the occurrence of abnormal images such as image deletion in a high humidity environment. In a low-humidity environment, the surface resistance of the discharge wires (32, 42) becomes large, and a large discharge may occur accidentally. However, by removing NOx as described above, the Discharge unevenness can also be prevented.

Further, in the present embodiment, the amount of nitric acid or nitrate adhering to the surface of the photoreceptor drum (10Y, 10C, 10M, 10Bk) can be reduced or almost eliminated as compared with the prior art. it can. Therefore, the cleaning device (14Y, 14C, 14M, 14Bk) for cleaning the surface of the photosensitive drum lowers the pressing force of the cleaning blade as compared with the conventional cleaning device that needs to scrape off the nitric acid or nitrate film. And the life of the photosensitive drum can be extended.

[Second Embodiment] Next, another embodiment (hereinafter, this embodiment is referred to as "second embodiment") in which the present invention is applied to a copying machine similar to the first embodiment will be described. In the configuration of the above embodiment, each photosensitive drum (10
The transfer residual toner remaining on the Y, 10C, 10M, and 10Bk is removed by a cleaning device (14Y, 14C, 14M,
14Bk). In this case, the life of the photosensitive drum can be made longer than before, but still, a pressing force for removing the transfer residual toner must be applied to the photosensitive drum. Therefore, in a second embodiment, a copier to which a cleaner-less system that collects the transfer residual toner on the photosensitive drum without using the cleaning device will be described.

FIG. 5 shows four photosensitive drums (10Y, 10C, 10M, 1) provided in the copying machine according to this embodiment.
0Bk). This copying machine has substantially the same configuration as the copying machine according to the above-described embodiment except that a cleaning device is not provided around the photosensitive drum 10Y. In this copying machine, the transfer residual toner remaining on the photosensitive drum 10Y after the transfer is moved as it is as the photosensitive drum rotates, and is collected by a developing device 113Y as a developing unit. Then, the transfer residual toner collected by the developing device 113Y again contributes to the development.

Here, the physical action of the residual toner in the cleanerless system will be described. FIG. 6 is an explanatory diagram for explaining the physical action given to the transfer residual toner. The toner image 60a on the photosensitive drum 10Y formed by the development of the developing device 113Y is transferred by Coulomb force onto the recording paper 100 to which the charge of the opposite polarity to that of the toner is applied by the transfer device 22Y. Further, the toner that has not been transferred onto the recording paper 100 remains on the photosensitive drum 10Y as a transfer residual toner 60b. At the time of this transfer, the recording material 1
In some cases, a part of the charge applied to the toner may be injected into the toner. Therefore, the transfer residual toner 60b includes a toner having a regular charge and a toner whose polarity has been changed by the transfer.

After the transfer, the transfer residual toner 60b is conveyed with the rotation of the photosensitive drum 10Y, and a charging device 11Y for adjusting the surface of the photosensitive drum to a uniform potential.
Gives a charge. As a result, the polarity of the transfer residual toner 60b having both the positive and negative polarities is adjusted to the same polarity. In the cleanerless system according to the present embodiment, the charging polarity of the surface of the photoconductor drum 10Y is the same as the normal charging polarity of the toner.

In the present embodiment, the photosensitive drum 1
The 0Y surface is negatively charged by the charging device 11Y, and the toner in the developing device 113Y is negatively charged. At this time, the recording paper 100 is
Positive charge is provided by 2Y. Therefore, the transfer residual toner 60b whose polarity has been reversed to the positive polarity during the transfer,
By passing through the charging region of the charging device 11Y, the charging device 11Y is returned to the normal polarity of negative polarity.

As described above, the transfer residual toner 6 that has reached the developing device 113Y after making one rotation around the photosensitive drum 10Y.
0c is collected by the developing device or remains on the photosensitive drum as it is, according to the difference between the surface potential of the photosensitive drum and the developing bias applied by the developing device. The toner remaining on the photosensitive drum 10Y becomes a part of the toner image and contributes to image formation in the next image forming step.

FIG. 7 is a diagram for explaining the potential in the developing area of the developing device 113Y. In this figure, the potential of a non-exposed portion where an electrostatic latent image is not formed on the surface of the photoreceptor drum 10Y in the developing area is V _H , the potential of an exposed portion where an electrostatic latent image is formed is V _L , is indicated by _{V B} the developing bias provided by 113Y.

For example, when the above _{VH is set} to -500 V, and V _L
Was a -100 V, the description will be given of a case where the -350V to _{V B,} in out view 7 of the transfer residual toner 60c A
The toner A in the non-exposed portion indicated by
To -500 V, the same as _VH . Therefore, this toner A has only | V _H -V _B | = 150 V,
A Coulomb force that moves to the developing device 113Y having a lower potential acts, and is collected by the developing device. On the other hand, among the transfer residual toner 60c, the toner B in the exposed portion indicated by B in FIG.
Has been charged, the toner B, | _V B -V _L |
= 250 V, low potential photosensitive drum 10
A Coulomb force acting to stay on the Y side acts to form a toner image together with the toner C developed from the developing device 113Y.

As described above, in the second embodiment, the use of the cleaner-less system eliminates the need for providing a cleaning device, so that the cleaning blade does not deteriorate the photosensitive drum surface. Therefore, it is possible to greatly extend the life of the photosensitive drum. In addition, the cost can be reduced and the size of the image forming engine or the cartridge can be reduced because the cleaning device is omitted.

The developing device used in the first and second embodiments may be one-component development or two-component development. In the copying machine employing the cleanerless system as in the second embodiment, the coulomb force is used when the transfer residual toner on the photosensitive drum is collected by the developing device in either one-component development or two-component development. However, in order to enhance the effect, it is preferable to adopt a contact development method in which development is performed while the developer or toner is in contact with the surface of the photosensitive drum. During this development, D
A developing bias including not only the C component but also an AC component having various waveforms may be applied.

FIG. 8 is a schematic diagram showing an example of a developing device using a two-component developer. The developing device 200 is provided with a developing sleeve 201. The developing sleeve 201 is formed of a non-magnetic conductive member such as aluminum or stainless steel, and its surface is provided with appropriate unevenness by sandblasting or the like. A plurality of fixed magnets 203 are provided inside the developing sleeve 201. A developing bias is applied to the developing sleeve from a power source (not shown). The developer reservoir A formed inside the developing device 200 is provided with two stirring members 204 for stirring the developer while moving the developers in mutually opposite directions. Further, a doctor blade 202 for regulating the developer carried on the developing sleeve 201 is also provided.

In the developing device 200, when the toner is consumed by the development, a corresponding amount of the toner is supplied from the toner bottle 205. The supplied toner is mixed with the developer in the developer reservoir A by the stirring member 204. When the developer stirred and conveyed by the two stirring members 204 reaches the vicinity of the developing sleeve 201, the developer is pumped up by the developing sleeve by the action of the fixed magnet 203. The pumped-up developer convects downstream of the doctor blade 202 to mix the toner and the carrier, and the toner is charged sufficiently and uniformly.

The developer regulated by the doctor blade 202 is raised in the developing area facing the photosensitive drum 10 by the fixed magnet 203, and the ear contacts the photosensitive drum 10. Then, the toner is moved to the electrostatic latent image side by an electric field between the developing sleeve 201 and the electrostatic latent image formed on the photosensitive drum 10 and is developed.

As the two-component developer, for example, a carrier in which ferrite particles having a particle diameter of 50 μm are used as a core material and the surface of which is coated with a silicone resin, and a mass average particle diameter is 7.
5 μm of a toner mainly composed of a thermoplastic resin colored with carbon black and a toner concentration of 5 wt.
% Can be used.

FIG. 9 is a schematic diagram showing an example of a developing device using a one-component developer. The developing device 300 is provided with a developing sleeve 301. The developing sleeve 301 is formed of a conductive member such as rubber having appropriate elasticity. Also, this developing sleeve has
A developing bias is applied from a power source (not shown). A toner supply roller 304 is arranged so as to be in contact with the developing sleeve 301. In this contact portion, charge is given to the toner by contact charging or charge injection between the toner and the developing sleeve 301. Then, a Coulomb force is generated between the toner and the developing sleeve 301, and the toner is carried on the developing sleeve. At this time, if necessary, the toner supply roller 3
A bias may also be applied to 04.

The toner carried on the developing sleeve 301 is regulated by a toner layer forming blade 302, and is thinned on the developing sleeve to form a toner layer. Conveyed to the area. Then, in this development area, the toner layer comes into contact with the surface of the photoconductor drum 10, and the toner is applied to the toner by the electric field between the development sleeve and the electrostatic latent image formed on the photoconductor drum. It moves to the electrostatic latent image side, and development is performed.

As the one-component developer, for example, a toner mainly composed of a thermoplastic resin having a mass average particle diameter of 7.5 μm and colored with carbon black can be used. It should be noted that a configuration in which a magnetic material is contained in the toner and a magnet is included in the developing sleeve, and a toner layer is formed and conveyed using magnetic force can also be used.

In the above-described two embodiments, a corotron type or scorotron type discharge device using a discharge wire as a discharge electrode has been described. However, the present invention is not limited to this. A discharge device having an electrode, a discharge device having an electrode having a fine structure, a device having a roller-like, plate-like, brush-like, or the like electrode in proximity to a discharge target can be applied. FIG. 10 illustrates an example in which a discharging device having a roller-shaped electrode is applied to the charging device. The charging device 111 generates a discharge in a minute gap between the charging roller and the photosensitive drum by a charging roller disposed in proximity to the photosensitive drum 10 to be discharged. Charge. In addition, these discharge devices may be configured to apply only a DC component to an electrode to cause a discharge, but may apply a bias including not only a DC component but also an AC component.

Further, in the above-described embodiment, a color copying machine is provided in which a plurality of photosensitive drums as latent image carriers are provided, and each color toner image formed on each photosensitive drum is directly transferred to recording paper as a recording material. Although the present invention has been described, the present invention uses a single latent image carrier to transfer each color toner image sequentially formed on the latent image carrier onto an intermediate transfer body as a transfer material and transfer the same. The present invention can also be applied to a material that is transferred to a recording material.

[Examples] Next, comparative experiments performed on a copying machine using the photocatalytic substance according to the present invention and a conventional copying machine not using the photocatalytic substance will be described. Both copiers have the same configuration except for a configuration that includes a photocatalyst material. Incidentally, a corotron charging device is used as the both uniform charging means, and a corotron transfer device is used as the transfer means. In this experiment, these copiers were installed in a high-temperature, high-humidity environment, and about 10,000 copies were made. After the copying, these copiers were stopped and left overnight in that environment. The following morning, these copiers were restarted, and the copied images were observed.

As a result of this observation, a copy image in a state where the image was flowing was obtained in the conventional copying machine. This is because NOx in the apparatus falls on the photosensitive drum, and the NOx reacts with moisture in the air to form HNO ₃ or NH _4.
It is considered that the compound was changed to a compound of nitric acid or nitrate such as NO ₃ . When a compound of nitric acid or a nitrate is formed on the surface of the photoreceptor drum, the resistance of the surface of the photoreceptor drum is reduced. As a result, even if a charge is applied to the surface of the photosensitive drum, the charge cannot be maintained at a predetermined position on the photosensitive drum, and the electrostatic latent image formed by the charge is destroyed. It is presumed to be due to this. On the other hand, in the copying machine according to the present invention using the photocatalyst substance, a copy image in a state where the image flowed did not appear, and a high-quality image was obtained.

[0080]

According to the first to fourteenth aspects of the present invention, since the discharge products can be removed by the reducing action of the photocatalytic substance, an abnormal image such as an image flowing does not occur and the image quality is improved. There is an excellent effect that a novel color image forming apparatus that can be provided can be provided.
Further, there is no need to mechanically rub and remove a nitric acid or nitrate film made of NOx as in the related art, and there is an excellent effect that the life of the image carrier can be extended.

In particular, according to the invention of claim 2, since the surface of the latent image carrier is not deteriorated by the cleaning member, there is an excellent effect that the life of the latent image carrier can be extended.

According to the third aspect of the present invention, the photocatalytic substance to be used can be irradiated with light having an optimum wavelength, so that the efficiency of decomposition of discharge products by the photocatalytic substance can be improved, and higher image quality can be achieved. There is an excellent effect that can be obtained.

According to the fourth to fourteenth aspects of the present invention, it is possible to remove a discharge product generated by a discharge without providing a new member or device, thereby providing a color image forming apparatus having a simple configuration. There is an excellent effect that can be. Furthermore, since the configuration can be simplified in this way, there is an excellent effect that the maintenance work can be reduced.

In particular, according to the fourth aspect of the present invention, there is no need to provide a new member or device for irradiating the photocatalytic substance with light, and it is possible to provide a color image forming apparatus having a simple configuration. Has an effect.

According to the fifth aspect of the present invention, since the discharge products can be removed at the position closest to the location where the discharge occurs, the discharge products can be efficiently decomposed and higher image quality can be obtained. There is an excellent effect that you can.

In particular, according to the invention of claims 6 to 8, since the discharge products can be removed before the discharge products flow out of the casing of the discharge means, higher image quality can be obtained. There is an excellent effect that it can be done.

According to the ninth to fourteenth aspects of the present invention,
Since discharge products can be removed more efficiently,
There is an excellent effect that higher image quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an entire copying machine according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a corotron discharge device.

FIG. 3 is a schematic configuration diagram of a scorotron discharge device.

FIG. 4 is a schematic configuration diagram showing another configuration example of the corotron discharge device.

FIG. 5 is a schematic configuration diagram illustrating a main part of a copying machine according to a second embodiment.

FIG. 6 is an explanatory diagram illustrating a physical action given to a transfer residual toner in the cleanerless system.

FIG. 7 is an explanatory diagram showing a potential potential in a developing area in a cleanerless system.

FIG. 8 is a schematic configuration diagram of a two-component developing device.

FIG. 9 is a schematic configuration diagram of a one-component developing device.

FIG. 10 is a schematic configuration diagram showing another configuration example of the charging device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scanner part 2 Printer part 10 Photoreceptor drum 11,111 Charging device 12 Optical writing unit 13,113 Developing device 14 Cleaning device 20 Transfer unit 21 Transfer belt 22 Transfer device 23 Separation device 24 Belt neutralization device 30 Corotron discharge device 40 Scorotron discharge device 31, 41 Casing 32, 42 Discharge wire 33, 43 High voltage power supply 34 Light emitting body 44 Grid 50 Photocatalytic substance 60 Toner 100 Recording paper

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/14 101 G03G 15/16 102 2H071 15/16 102 H05F 3/04 C 2H077 21/06 G03G 15 / 08 507B 5G067 H05F 3/04 21/00 340 (72) Inventor Hiroshi Yasutomi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd. (72) Inventor Masahiko Akato 1-chome Nakamagome, Ota-ku, Tokyo No. 3-6 Inside Ricoh Co., Ltd. (72) Inventor Hirokatsu Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo F-term inside Ricoh Co., Ltd. 2H003 AA18 CC01 CC04 EE03 2H027 EA09 JA01 JA02 JB05 JB06 JC03 ZA07 2H030 AA05 AD02 AD16 2H032 AA02 BA29 BA30 DA03 2H035 AA01 AA02 AZ05 2H071 BA03 DA06 DA07 DA09 DA10 2H077 AA37 AC16 GA04 5G067 AA65 D A19

Claims (14)

[Claims] A color image forming apparatus comprising a discharge means for a discharge object and developing with a plurality of color developers to form a color image, wherein a discharge product generated by the discharge of the discharge means is discharged. Discharge product decomposing means having a decomposable photocatalytic substance, and light irradiating means for irradiating the discharge product decomposing means with light having a wavelength component for exciting the photocatalytic substance during the discharge are provided. A color image forming apparatus, comprising: 2. The color image forming apparatus according to claim 1, further comprising: developing means for developing the latent image formed on the latent image carrier, wherein the developing means includes a transfer residual portion remaining on the latent image carrier. A color image forming apparatus having a function as a cleaning unit for cleaning toner. 3. A color image forming apparatus according to claim 1, wherein a light emitting body is used as said light irradiating means. 4. A color image forming apparatus according to claim 1, wherein a discharge means for performing discharge with light emission is used as said discharge means, and said discharge means is used as said light irradiation means. Image forming device. 5. A color image forming apparatus according to claim 1, wherein a photocatalytic substance capable of decomposing a discharge product generated by the discharge of said discharge means is provided to a constituent member of said discharge means. A color image forming apparatus using the constituent member as the discharge product decomposing means. 6. The discharge device according to claim 5, wherein said discharge means includes a discharge electrode, and a casing surrounding said discharge electrode and having an opening for discharging said discharge to a discharge target.
The color image forming apparatus according to any one of the preceding claims, wherein the constituent member is the casing. 7. The discharge device according to claim 5, wherein said discharge means comprises a discharge electrode and a casing surrounding said discharge electrode and having an opening for performing said discharge to a discharge target.
Or the color image forming apparatus according to 6, wherein the constituent member is the discharge electrode. 8. The discharge means includes: a discharge electrode; and a casing surrounding the discharge electrode and having an opening for performing the discharge to a discharge target, and a casing having a grid formed in the opening. 8. The color image forming apparatus according to claim 5, 6 or 7, wherein said constituent member is said grid. 9. A color image forming apparatus according to claim 5, further comprising a uniform charging means for uniformly charging said latent image carrier, wherein said discharging means comprises said uniform charging means. A color image forming apparatus, comprising: 10. The image forming apparatus according to claim 5, further comprising a charge removing means for removing charge from the image bearing member after transferring the toner image on the image bearing member.
7. The color image forming apparatus according to 7, 8, or 9, wherein the discharging means is the discharging means. 11. A transfer device for transferring a toner image formed on an image carrier to a transfer material.
9. The color image forming apparatus according to 9 or 10, wherein the discharging means is the transfer means. 12. A recording medium according to claim 5, further comprising a separating unit for separating the recording material from a conveying member for conveying the recording material after transferring the toner image formed on the image carrier onto the recording material.
7. The color image forming apparatus according to 7, 8, 9, 10 or 11, wherein the discharging means is the transferring means. 13. A transfer member discharging means for transferring a toner image formed on an image carrier onto a recording material conveyed by a conveying member and then discharging said conveying member. , 7, 8, 9, 10, 11 or 12, wherein the contact-type discharging means is the conveying member static elimination means. 14. The method of claim 1, 2, 3, 4, 5, 6, 7,
8. The color image forming apparatus according to 8, 9, 10, 11, 12, or 13, wherein the photocatalytic substance is titanium oxide.