JP2001083809A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently reduce concentration of electrostatic discharge product material such as ozone, NOx or the like to arise even when adopting the ion generating device capable of discharging by the voltage being lower than that of the corona charger. SOLUTION: In the case of adopting an ion generating device 20 generating the ion, consisting of an induction electrode 22 and the ion generating electrode 24 formed by holding an induction body 23 between them, by applying the AC voltage between the induction electrode 22 and the ion generating electrode 24, this image forming device is let to efficiently decomposing ozone and NOx standing for discharge product material generating in the discharge section vicinity by disposing photocatalyst material 40 desiring resolution of discharge production material in the discharge section vicinity causing atmospheric discharge as the paper separation device, for lowering the concentration thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus using an ion generator as a paper separating apparatus, and more particularly, to an efficient and efficient method for generating discharge products generated by an ion generator in an electrophotographic image forming process. The present invention relates to an image forming apparatus that can be reliably disassembled.

[0002]

2. Description of the Related Art An electrophotographic image forming process is used.
Image forming apparatuses such as copiers, printers and facsimile machines
In many cases, corona discharge or the like is used. An example
For example, a charging unit that uniformly charges the photoconductor,
Transfer unit for transferring formed toner image to recording paper and photosensitive
Equipped with a static elimination section that eliminates body residual charge and residual toner charge
I have. In addition, a photoconductor on a first image carrier called a photoconductor is used.
Transfer the toner image onto a second image carrier, for example, a recording paper.
After the transfer, the charge on the reverse side of the charged recording paper
To remove static electricity from the transfer paper and easily remove it from the photoreceptor.
It is used as a charge applying device for separating paper.
These parts often use air discharge,
A discharge product is generated by this air discharge. For example, oh
Dzong, NO _xThere is. Ozone is a high concentration image forming device
When it stays in the photoconductor, it oxidizes the photoconductor surface,
Deterioration and deterioration of charging ability will occur, resulting in deterioration of the formed image
You. In addition, deterioration of members other than the photoconductor is promoted, and component life is shortened.
There are also problems such as a loss of life.

[0003] When high-concentration ozone is discharged out of the image forming apparatus, there is a concern that the odor of ozone may cause discomfort to surrounding people, or may cause adverse effects on the human body such as suffering from allergic symptoms. The concentration of ozone discharged to the outside of the image forming apparatus is regulated. For example, according to the Blue Angel Mark Examination Standard (RAL-UZ62) in Germany, the discharge concentration outside the apparatus is regulated to 0.01 ppm or less.

Conventionally, in an image forming apparatus, ozone around a photoreceptor is sucked by a fan and discharged to the outside of the image forming apparatus through an ozone filter.

However, in such a conventional ozone treatment method, there is a problem that the filter gradually deteriorates due to adsorption of ozone, and it becomes impossible to remove ozone properly after long-term use. Further, in order to improve the ozone removal rate by the filter, if the mesh of the filter is made fine or the thickness of the filter is increased to increase the surface area of the filter, the pressure loss in the filter increases, and the capacity becomes large. It is necessary to attach a fan, so that the cost of the image forming apparatus is increased, power consumption is increased, and noise is increased.

[0006] Another major discharge product, NO _x
In the case of (1), although there is no restriction on discharge outside the apparatus at present, it also has an adverse effect on members inside the image forming apparatus.
It is known that when discharge occurs, NO _x is formed, but it reacts with moisture in the air to produce nitric acid and also reacts with metal to produce metal nitrate. These products have high resistance in a low humidity environment, and adhere to an ion generating head or the like, thereby causing a problem that discharge becomes unstable and uneven charging occurs. Further, when a thin film made of nitric acid or nitrate is formed on the surface of the photoreceptor, an abnormal image appears as if the image was flowing in a high humidity environment. This is because nitric acid / nitrate absorbs moisture to lower the resistance, and the electrostatic latent image on the surface of the photoreceptor is broken.

[0007] A method has been adopted in which deposits on the surface of the photoreceptor are removed by removing the photoreceptor little by little during cleaning. However, the problem of deterioration due to cost increase and aging occurs, and is not an essential solution.

[0008] In this regard, in the prior art, by utilizing the discharge product decomposing action by photocatalytic material, the ozone in the image forming apparatus, a method of degrading NO _x are proposed. For example, an electrophotographic developer that reduces discharge products generated by aerial discharge by adding semiconductor particles carrying a metal as an external additive or in a toner containing at least a binder resin and a colorant (particularly, Japanese Unexamined Patent Publication No. Hei 5-134445), at least one of an eraser lamp, a pre-transfer neutralizing lamp, and a part receiving light from a neutralizing lamp provided around an image carrier is coated with semiconductor fine particles carrying a metal ( Japanese Patent Application Laid-Open No. 6-59551 and Japanese Patent Application Laid-Open No. Hei 7-59551 have been proposed.
No. 92788).

That is, in each of these proposals, the concentration of ozone flowing out of the charger and the like is reduced by making it easier for ozone to be decomposed in the image forming apparatus, and the load on the ozone filter is reduced. be able to.

Other conventional examples are listed below. For example, according to Japanese Patent Laid-Open No. 5-303244, using the waste heat of the fixing unit, NO _X is to prevent from becoming nitrate. According to JP-A-6-167857, deterioration of the photoconductor is prevented by using the exhaust heat of the fixing unit to decompose ozone in the discharge member. According to JP-A-6-317974, generation of ozone is suppressed by disposing a catalyst in the vicinity of the occurrence of discharge. According to Japanese Patent Application Laid-Open No. 7-134473, generation of ozone is suppressed by using a catalyst and heat. According to JP-A-9-114191, the surface of the charger, the for charging the photosensitive member by causing separate creeping glow discharge, and so as to decompose the NO _X. According to Japanese Patent Application Laid-Open No. 9-138819, ozone in an ozone suction duct is decomposed by irradiating light, and the life of the ozone decomposition filter is extended by improving the decomposition efficiency. I have. JP-A-10-90
According to Japanese Patent No. 974, ozone is decomposed by providing a catalyst on the sawtooth electrode. JP-A-10-3
According to Japanese Patent No. 01364, generation of ozone is prevented by flowing a non-ozone-generating gas to a discharge portion.
Further, according to Japanese Patent Kokoku 8-23715, by covering the neutralizing material to the inside of the discharge vessel, so that neutralizing the NO _X prevent degradation of the photoreceptor.

[0011]

However, in such conventional image forming apparatuses and discharge product reduction methods, since the load on the filter is reduced, there is still room for improvement. is there.

That is, since the concentration of the discharge product flowing out of the charger or the like is reduced, the discharge product flowing out of the charger diffuses into the image forming apparatus and reacts with the catalyst substance. There is a demand for a reduction in the probability of reducing the concentration of the discharge product, a low efficiency in reducing the concentration of the discharge product, and an efficient reduction in the concentration of the discharge product.

[0013] Further, the ion generating electrode includes an induction electrode and an ion generation electrode formed with a dielectric material interposed therebetween, and applies an AC voltage between the induction electrode and the ion generation electrode to cause an air discharge to generate ions. Charging device using the device,
In a transfer device and a static eliminator, discharge can be generated with a smaller voltage than a general corona charger. Therefore, the amount of discharge products is smaller than that of a general corona charger.

A problem in using such an ion generator that causes an aerial discharge through the dielectric layer is that a nitrate is formed by the discharge, and the nitrate adheres to the surface of the dielectric layer to generate a discharge. May not work. In order to prevent this, the ion generator itself is heated or the like.

[0015] The amount of ions generated by the ion generator is also affected by the heating temperature. Since the amount of generated ions is easily affected by temperature fluctuations, a temperature controller is required (US Pat. No. 4,155,093;
JP-A-278258, JP-A-5-281834, JP-A-6-75457, JP-A-8-8298
0, JP-A-10-21395).

However, it does not mean that the amount of discharge products generated in the ion generator is completely eliminated. Also in the ion generator, there is a demand for efficient reduction of the discharge product concentration.

Accordingly, the present invention provides an ozone and NO _x discharge product due to aerial discharge even when an ion generator that generates a relatively small amount of discharge product as compared with a corona charger is used in a paper separation device. It is an object of the present invention to provide an image forming apparatus capable of efficiently lowering the density of an image before flowing out and suppressing an adverse effect on the environment.

[0018]

According to the first aspect of the present invention,
An ion generator comprising at least an induction electrode and an ion generation electrode formed with a dielectric material interposed therebetween, and applying an AC voltage between the induction electrode and the ion generation electrode to cause air discharge to generate ions. Is provided as a paper separating device, and an image formed on the first image carrier is transferred to a second image carrier according to an electrophotographic process, and then the back surface of the second image carrier is charged by the ion generator. In the image forming apparatus, the second image carrier is easily separated from the first image carrier by applying a photocatalyst substance for decomposing a discharge product near a discharge point of the ion generator. Provided.

[0019] Therefore, the light emission of the discharge, the photocatalytic material is activated, since the reaction with discharge products, discharge products generated by the ion generating device as a paper separator, in particular decomposition of ozone and NO _x efficiently . Thereby, the discharge product can be decomposed before flowing out of the ion generator, and thus it is possible to prevent the adverse effects on the surrounding members and to suppress the adverse effects on the environment.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the photocatalytic substance is provided on at least the surface of the dielectric on the side of the ion generating electrode.

Accordingly, the light emission of the discharge activates the photocatalytic substance in the vicinity of the ion generating portion and reacts with the high-concentration discharge product, so that the discharge products generated during the paper separation discharge, particularly, ozone and NO _x. Can be efficiently decomposed. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to a third aspect of the present invention, in the image forming apparatus of the first aspect, at least the ion generating electrode contains the photocatalytic substance.

Accordingly, the discharge products generated in the paper separating device can be efficiently decomposed in the generating section having the highest concentration of the discharge products. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to a fourth aspect of the present invention, in the image forming apparatus of the first aspect, the ion generating electrode is coated with a dielectric, and has a photocatalytic substance on at least a surface of the coating layer.

Therefore, the discharge products generated in the paper separating apparatus can be efficiently decomposed in the generating section having the highest discharge product concentration. Further, since the photocatalytic substance is provided on the surface of the coating layer, the function of the coating layer is not impaired. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to a fifth aspect of the present invention, in the image forming apparatus of the first aspect, the ion generating electrode is coated with a dielectric, and at least this coating layer is made of a substance containing a photocatalytic substance.

Accordingly, since the photocatalytic substance is included in the coating layer, it is not necessary to newly provide a photocatalytic substance coating layer. This simplifies the coating and is advantageous in terms of production and cost. If the photocatalytic substance is only on the surface of the coating layer, the function will be lost if the coating layer of the photocatalytic substance is peeled off. In contrast, when the photocatalytic substance is included in the coating layer,
Even if the coating layer is slightly worn due to electric discharge or the like, the photocatalytic effect can be maintained because the coating layer is included inside the coating layer. In addition, the discharge product generated in the paper separating device can be efficiently decomposed in the generating section having the highest concentration of the discharge product. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

[0028] The invention according to claim 6 is the invention according to claims 1 to 5.
In the image forming apparatus according to any one of the above, a light emitter capable of irradiating at least light containing ultraviolet light is provided in the vicinity of the discharge location.

Accordingly, the photocatalytic substance can be more strongly activated by the ultraviolet light of the light-emitting body such as a lamp, so that the discharge products can be efficiently decomposed. Further, even when the ion generator does not emit light, the photocatalytic substance can be activated by the ultraviolet light of the luminous body, so that it can be decomposed even if a discharge product remains. Thereby, the discharge product can be more reliably decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to a seventh aspect of the present invention, in the image forming apparatus of the sixth aspect, the luminous body has a photocatalytic substance at least on a luminous surface thereof.

Accordingly, the photocatalytic substance can be more strongly activated by the ultraviolet light of the luminous body such as a lamp, so that the discharge products can be efficiently decomposed. Furthermore, since the photocatalytic substance is disposed on the surface of the light emitting body, it is possible to prevent the surface of the light emitting body from being stained by the adhesion of the discharge product. In addition, when a photocatalytic substance is disposed on the surface other than the light emitting body, even when the ion generator does not emit light, the photocatalytic substance can be activated by the ultraviolet light of the light emitting body, so that the discharge generating Things can be decomposed efficiently. In addition, since the surface of the light emitting body is not stained, the light transmittance of the light emitting body surface does not decrease. Therefore, the photocatalyst can be irradiated with light for a long time, and the photocatalyst can be activated. Thereby, the discharge product can be more reliably decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to an eighth aspect of the present invention, in the image forming apparatus according to the sixth or seventh aspect, the wavelength of the light emitted from the luminous body includes light of 300 nm to 400 nm.

When a photocatalytic substance is irradiated with light having a certain energy or more, it is rapidly activated and the reaction proceeds. For example, in the case of titanium oxide, the wavelength of light serving as the threshold value is 380 nm. Therefore, if the wavelength of the ultraviolet light to be irradiated is set to be appropriate and the photocatalytic substance is more easily activated, the decomposition efficiency of the discharge product becomes very high. Thereby, the discharge product can be more reliably decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to the ninth aspect of the present invention, there are provided the first to eighth aspects.
In the image forming apparatus according to any one of the above, the photocatalytic substance is an n-type semiconductor.

Accordingly, n having high efficiency as a photocatalytic substance
By using a photocatalytic substance made of a type semiconductor, it is possible to efficiently decompose discharge products. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the n-type semiconductor is titanium oxide.

Accordingly, titanium oxide is an n-type semiconductor photocatalyst and is currently said to be the most stable and efficient. By using titanium oxide for the photocatalyst, discharge products can be efficiently decomposed. This allows the discharge products to decompose before flowing out of the casing,
An adverse effect on the photoreceptor and the like can be prevented, and an adverse effect on the environment can be suppressed.

According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, the titanium oxide has at least an anatase type crystal structure.

Accordingly, titanium oxide having an anatase structure in its crystal structure has the highest effect as a photocatalyst, so that discharge products can be decomposed efficiently. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

[0040]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 to 7 show an embodiment of the image forming apparatus of the present invention. FIG. 1 shows an image forming apparatus 1 to which an embodiment of the image forming apparatus of the present invention is applied. FIG.

In FIG. 1, the image forming apparatus 1 includes a photoconductor 2 serving as a first image carrier which is driven to rotate clockwise in FIG. , A charging unit 3, a writing unit 4, a developing unit 5, a transfer unit 6, a paper separating unit 14 as a paper separating device, a cleaning unit 7, a photosensitive member removing unit 8, and the like are sequentially arranged according to an electrophotographic process. In addition, a toner neutralizing unit 9 is provided in front of the cleaning unit 7.

Further, the image forming apparatus 1 of the present embodiment
A paper feed cassette (not shown) for storing a plurality of recording papers P as a second image carrier is provided, and the recording papers P in the paper feed cassette are fed by a paper feed roller (not shown). After the sheets are fed one by one and the timing is adjusted by the registration roller pair 15, the sheet is fed between the transfer unit 6 and the photoconductor 2.

In the image forming apparatus 1 having such a configuration, first, the photosensitive member 2 is rotationally driven clockwise in FIG.
After the photoconductor 2 is uniformly charged by the charging unit 3, the writing unit 4 irradiates a laser modulated with image data to form an electrostatic latent image on the photoconductor 2, and the electrostatic latent image is formed. The developing unit 5 attaches toner to the photoconductor 2 thus developed, and develops. Next, the photosensitive member 2 on which toner is adhered in the developing section 5 to form a toner image
Is transferred onto the recording paper P conveyed between the photoconductor 2 and the transfer unit 6 by the transfer unit 6, and the recording paper P on which the toner image is transferred is conveyed to the fixing unit 10.

The fixing unit 10 includes a fixing roller 11 heated to a predetermined fixing temperature by a built-in heater, and a pressure roller 12 pressed against the fixing roller 11 at a predetermined pressure. The recording paper P is heated and pressurized to fix the toner image on the recording paper P to the recording paper P, and then discharged onto a discharge tray (not shown).

On the other hand, the photoconductor 2 on which the toner image has been transferred onto the recording paper P by the transfer unit 6 is further rotated, and the charge of the residual toner remaining on the photoconductor 2 is removed by the toner elimination unit 9.
After the toner remaining on the surface of the photoreceptor is scraped off by the cleaning unit 7 by the blade 13, the charge is removed by the photoreceptor discharging unit 8. Then, after the photoreceptor 2 having been neutralized by the photoreceptor neutralizing unit 8 is uniformly charged by the charging unit 3, the next image formation is performed in the same manner as described above. The cleaning unit 7 is not limited to the one that scrapes off the residual toner on the photoconductor 2 with the blade 13, but may be one that scrapes the residual toner on the photoconductor 2 with a fur brush, for example.

In such an image forming apparatus 1, in the present embodiment, for example, an ion generator as shown in FIG. 2 is used for the paper separating section 14 for easily separating the recording paper P from the photoreceptor 2. Have been. An ion generator may also be used for the charging unit 3, the transfer unit 6, the toner charge removing unit 9 and the photoconductor charge removing unit 8.

Here, the ion generator will be described with reference to FIG. FIG. 2A is a sectional structural view, and FIG. 2B is a plan view as viewed from an ion generating electrode side.

This ion generating device (the ion generating head 2)
0) denotes an induction electrode 2 on a substrate 21 made of ceramic or the like.
2 is formed, a dielectric layer 23 made of glass or the like is formed so as to cover the induction electrode 22, and an ion generating electrode 24 is formed on the dielectric layer 23. . Note that the induction electrode 22, the dielectric layer 23, and the ion generation electrode 24 can be formed by thick film printing. For example, the thickness of the induction electrode 22 is 1 to 5 μm,
The thickness of the dielectric layer 23 is preferably 20 to 50 μm, and the thickness of the ion generating electrode 24 is preferably 1 to 30 μm. The dielectric layer 23 preferably has a dielectric constant as high as possible. This is because the higher the dielectric constant, the larger the capacitance of the dielectric layer and the greater the distortion of the electric field.

A high frequency high voltage having a frequency of several hundred Hz to several tens kHz and a peak value of 1 to 4 kV is applied by a power source 26 between the induction electrode 22 and the ion generation electrode 24 of the ion generating head 20 having such a structure. And ion generating electrode 2
When a bias voltage is applied to 3 by a bias power supply 27,
In the vicinity of the ion generation electrode 24 (hereinafter, the ion generation space 29)
) Air is ionized, generating positive and negative ions. Here, as shown in the figure, when a negative voltage is applied as a bias voltage by the bias power supply 27,
Only negative ions are extracted from the ion part. If the bias voltage is positive, positive ions are extracted. The ion generating head 20 can generate discharge with a smaller voltage than a general corona charger.

The surface of the ion generating electrode 24 may be provided with a coating layer 30 of SiO ₂ . As a result, it is possible to prevent the ion generating electrode 24 from being deteriorated due to ion sputtering or oxidation.
4 can prevent creeping discharge. For example, the coating layer 30 is formed to have a thickness of 1 to 5 μm. If the coating layer 30 is too thick, the ion generation efficiency will decrease. The coating may be nitride, silicon nitride, magnesium oxide, titanium oxide, glass, and the like.

The dielectric layer 23 may be formed by sandwiching the resistor layer 25.

A power supply 28 is connected to the resistor layer 25, and can generate Joule heat by a current flowing through the resistor layer 25. The voltage from the power supply 28 is a DC or AC voltage. This Joule heat heats the dielectric layer 23 and the ion generation space 29. This makes it possible to further enhance the decomposition effect of the discharge product by the photocatalyst substance described later.

The conductive film for forming the resistor layer 25 is formed by
Chromium, copper, tungsten, aluminum, platinum, titanium, or the like may be formed by a method such as sputtering, and may be patterned by photolithographic etching.

The ion generating head 20 may be provided with a temperature sensor such as a thermistor 31 at an appropriate position as shown in FIG. 3A or 3B, for example, so that the heating temperature can be constantly monitored. . By feeding back the value of this sensor to the temperature controller, environmental fluctuations and abnormalities in the heating element occur, and the heating temperature is in a normal range (for example, 50 to 7).
0 ° C.) can be corrected.

As the resistor layer 25, a heating resistor having self-heating controllability may be used.

[0057] Also the case of using such an ion generating head 20, the generation of discharge products such as ozone and NO _X is not completely eliminated, in this embodiment, the photocatalytic material in the vicinity discharge points 40 is added. The place where the photocatalytic substance 40 is disposed is appropriate, and several examples thereof will be described with reference to FIGS.

First, when the coating layer 30 is not provided in the ion generating head 20, the dielectric layer 2
3. At least a part of the ion generating electrode 24 is coated with or contains the photocatalytic substance 40. FIG.
4A shows an example in which a photocatalytic substance 40 is applied to a part of the dielectric layer 23, and FIG. 4B shows an example in which the photocatalytic substance 40 is contained in a part of the dielectric layer 23. FIG. FIG. 4C shows an example in which the photocatalytic substance 40 is contained in all of the dielectric layer 23, and FIG.
Is applied.

When the coating layer 30 is provided in the ion generating head 20, a photocatalytic substance 40 is applied to the surface of the coating layer 30 as shown in FIG. Alternatively, as shown in FIG. 5B, the coating layer 30 contains the photocatalytic substance 40, or the coating layer 30 itself is made of the photocatalytic substance 40.

As shown in FIG. 6, a photocatalytic substance 40 may be arranged at least in a portion of the housing 32 of the ion generating head 20 facing the ion generating portion of the ion generating head 20.

Of course, these methods may be combined so that the effect of decomposing discharge products is most exhibited.

For such a photocatalytic substance 40, an n-type semiconductor such as titanium oxide is used. The n-type semiconductor has a function of decomposing ozone when a discharge product, for example, ozone comes in contact with the light irradiated. That is, when an n-type semiconductor such as titanium oxide is irradiated with light having a wavelength corresponding to the band gap, electrons are excited to the conduction band and holes are generated in the valence band. The excited electrons of the n-type semiconductor exert a reducing action, and when carrying a metal, electrons flow from the valence band to the metal, where the reducing action is exerted. As described above, by irradiating the n-type semiconductor with light having an appropriate wavelength, the discharge product is reductively decomposed by the reducing action of the excited electrons.

As the substance used as the photocatalytic substance 40, in addition to the above-mentioned titanium oxide, tungsten oxide, zinc oxide, cadmium oxide, tin oxide, indium oxide, silver oxide, manganese oxide, copper oxide, iron oxide, vanadium oxide,
Niobium oxide, cadmium oxide, titanium hydroxide and zinc hydroxide can be used, in particular, titanium oxide,
It is suitable in terms of reaction efficiency, durability, safety, and usable wavelength range. Further, titanium oxide is classified into three types, rutile type, anatase type, and brookite type, depending on the crystal structure. The anatase type structure is most suitable because it has a high effect as a photocatalyst.

As the photocatalytic substance 40, two or more of the above-mentioned substances may be mixed, and if Pt, Pd, Rh, Nb and the like are mixed, the photocatalytic action can be further promoted.

The photocatalytic substance 40 can be attached by forming it directly on the coating layer by 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. A commercially available photocatalyst fine powder can also be attached by adhering on the coating layer. Further, the photocatalytic substance 40 is mixed with the material constituting the coating layer to form each member, so that each member itself can have a photocatalytic action.

Aerial discharge is accompanied by light emission close to purple. It is known that ultraviolet light is included in the wavelength region of this purple light emission, and the ultraviolet light excites the photocatalytic substance 40, and the photocatalytic substance 40 can decompose a discharge product.

Next, the operation of the present embodiment will be described. The image forming apparatus 1 has a photocatalyst substance 40 in the charging section 3 using the ion generating head 20, and the photocatalyst substance 40 decomposes a discharge product in the vicinity of a discharge portion of the charging section 3. There is.

That is, after the photoreceptor 2, which is driven to rotate clockwise in FIG.
The writing unit 4 irradiates a laser modulated with image data to form an electrostatic latent image on the photosensitive member 2, and develops the photosensitive member 2 on which the electrostatic latent image is formed by attaching toner to the developing unit 5. . Then, the photoreceptor 2 on which the toner has been formed by attaching the toner in the developing unit 5 is transferred to the recording paper P conveyed between the photoreceptor 2 and the transfer unit 6 by aerial discharge in the transfer unit 6. In the transfer unit 6, a reverse charge is applied to the recording paper P from the toner, so that an electrostatic attraction acts between the recording paper P and the photoconductor 2. After the transfer, the charge on the back surface of the recording paper P is removed by air discharge in the paper separating unit 14 to separate the paper from the photoreceptor 2.

The recording paper P on which the toner image has been transferred is conveyed to the fixing unit 10, and the fixing unit 10 fixes the toner image on the recording paper P to the recording paper P, and then discharges the recording paper P onto the paper discharge tray.
Then, the photoconductor 2 on which the toner image has been transferred onto the recording paper in the transfer unit 6 is further rotated, and the charge of the residual toner remaining on the photoconductor 2 is removed by the air discharge in the toner discharging unit 9. After the toner remaining on the surface of the photoconductor 2 is scraped off by the cleaning unit 7 by the blade 13 and removed, the charge is removed by the photoconductor discharging unit 8.

[0070] In this image forming process, when utilizing the aerial discharge is ozone, discharge products such as NO _x is generated.

[0071] The photocatalytic material 40, when light emitted by the aerial discharge as described above is irradiated to activate exhibits a reducing action, decomposes discharge products such as ozone and NO _x.

Accordingly, the discharge products generated in the ion generating head 20 by air discharge are efficiently decomposed by the photocatalytic substance 40 near the ion generating head 20. As a result, it is possible to prevent, for example, ozone from oxidizing the surface of the photoreceptor 2 and deteriorating the image, and prevent ozone from flowing out of the image forming apparatus 1 and deteriorating the environment. be able to. Further, it is possible to prevent nitric acid and nitrate due to NO _x from adhering to the surface of the photoreceptor 2, and it is possible to prevent image deletion in a high humidity environment. Further, the adhesion of nitric acid or nitrate over time is less likely to occur, and it is possible to prevent discharge unevenness in a low humidity environment.

As described above, according to the present embodiment, by disposing the photocatalytic substance 40 on the ion generating head 20,
Decomposition occurs very close to the ozone and NO _x production sites, which is very efficient. In addition, since ultraviolet rays are also generated from the ion generating head 20, the decomposition efficiency is improved. Thereby, the discharge product can be decomposed before flowing out of the casing 32, and thus the adverse effects on the photoreceptor 2 and the like can be prevented, and the adverse effects on the environment can be suppressed. In addition, dirt of the ion generating head 20 due to nitric acid or nitrate, which is one of the discharge products, and adhesion to the surface of the photoconductor 2 are suppressed, whereby charging unevenness and image flow on the photoconductor 2 can be prevented. Further, a cleaning device for the ion generating head 20 is not required, so that cost and maintenance can be greatly reduced. The number of parts is reduced. Further, it is not necessary to scrape off the photoreceptor surface by the photoreceptor cleaning blade, the blade life is prolonged by reducing the pressing contact pressure, the deterioration is prevented, and the toner is not adhered to the photoreceptor 2 due to the strong pressing pressure. As a result, the thickness of the photoconductor 2 does not decrease with the passage of time, so that the process control load can be reduced and the life of the photoconductor 2 can be prolonged. Furthermore, since a compound such as silicon is laminated on the ion generating head 20 and the intensity of discharge becomes non-uniform, if the ion generating head 20 is used for a long time, the discharge becomes uneven and the charging becomes non-uniform. However, by disposing the photocatalytic substance 40,
Generation of the silicate compound formed on the ion generating head 20 can be suppressed, and the life of the ion generating head 20 can be extended.

In the present embodiment, the photocatalyst substance 40 is activated by utilizing the light generated in the discharge part,
Although a discharge product is decomposed, a lamp as a luminous body that emits light including a wavelength that excites the photocatalytic substance 40 as shown in FIG. 7 in order to improve the decomposition efficiency of the discharge product by the photocatalytic substance 40 50 may be provided.

For example, when the n-type semiconductor as the photocatalytic substance 40 is TiO ₂ , the lamp 50 only needs to include a wavelength of 400 nm or less, and an ordinary fluorescent lamp, halogen lamp, or the like may be used. If an ultraviolet lamp is used, the effect can be further improved.

When the surface of the lamp 50 is coated with the n-type semiconductor photocatalyst substance 40, the photocatalyst substance 40 coated on the lamp 50 is excited, and the discharge products contacting the lamp 50 can be decomposed. .

When the lamp 50 is provided in this manner, even when there is no light emission due to the discharge, the light of the lamp 50 activates the photocatalyst substance 40 attached to the member, so that the discharge product can be decomposed and the discharge product can be decomposed. The decomposition efficiency of the product can be improved.

Here, in order to verify the effect of the photocatalyst substance 40 described above, the following comparative experiment was performed. First, an ion generator coated with titanium oxide and one not coated were prepared. The apparatus alone was set in a laboratory environment, an AC voltage (3.0 kV, 5 kHz) was applied between the induction electrode and the ion generation electrode, and a discharge occurred at the ion generation electrode. Then, air 5 mm ahead was sucked from the ion generating electrode where the discharge product was most present. The concentration of ozone and NO _x contained in the sucked air was measured (ozone measuring instrument: Dairekku Co. DY1500, NO _x
Measuring instrument: APNA300, manufactured by Horiba, Ltd.) The measurement was performed continuously for 10 minutes after the discharge became stable, and the average value was obtained.

[0079] First, the measured concentration of ozone and NO _x in the ion generating device alone that is not coated with titanium oxide was 6.8ppm and 0.43 ppm.

On the other hand, the concentrations of ozone and NO _x were measured with an ion generator coated with titanium oxide. Titanium oxide was applied to the dielectric layer of the ion generator and the inside of the housing. Then, a voltage was applied and the concentration was measured in the same manner as described above. As a result of the measurement, the ozone concentration was 0.75 pp.
m, NO _x became 0.080ppm.

Further, also in the case where the ion generating head coated with titanium oxide was irradiated with an ion generating head by an ultraviolet lamp, the ozone and NO _x concentrations were measured.
At this time, the ozone concentration is 0.40ppm, NO _x is 0.
It was 019 ppm.

A verification experiment on the image deletion phenomenon was also performed.
First, a copier (imagio MF) manufactured by our company using an ion generator without a photocatalytic substance according to the present invention in a paper separation unit.
-4550 modified machine) was installed under high temperature and high humidity environment. He made about 10,000 copies. After the preparation, the copying machine was stopped, the operation was suspended overnight in a high-temperature, high-humidity environment, and the operation was restarted the next morning. As a result, a phenomenon called "image deletion" was observed in the copied image. This flight of the NO _x reacts with moisture in the air, changes in nitrate or nitrate compounds (such as _{HNO 3, NH 4 NO 3)} , is believed to be because that Furitsumo' on the photoreceptor.
This nitric acid / nitrate compound is an insulator at low humidity, but lowers the resistance of the photoreceptor surface at high humidity. That is, even if a charge is applied to the photoreceptor surface, the charge on the photoreceptor surface cannot be maintained at that location, so that the electrostatic latent image is destroyed. Therefore, it is considered that an image flow occurs.

On the other hand, when the ion generator using the photocatalyst substance according to the present invention was used in the above-mentioned copying machine manufactured by our company using the paper separation unit, no image deletion phenomenon appeared even when the same experiment was performed. Things.

[0084]

According to the first aspect of the present invention, the light emission of the discharge activates the photocatalytic substance and reacts with the discharge product, so that the discharge product generated by the ion generator as the paper separating device, especially the discharge product, the ozone and NO _x efficiently can be disassembled,
Thereby, the discharge product can be decomposed before flowing out of the ion generator, and thus it is possible to prevent the adverse effects on the surrounding members and to suppress the adverse effects on the environment.

According to the second aspect of the present invention, the light emission of the discharge activates the photocatalytic substance in the vicinity of the ion generating portion and reacts with the high-concentration discharge product. the product, in particular can efficiently decompose ozone and NO _x, thereby, discharge products can be broken down before flowing out of the casing, it is possible to prevent adverse effects on the photosensitive body or the like, an adverse effect on the environment Can be suppressed.

According to the third aspect of the present invention, the discharge products generated in the paper separating apparatus can be efficiently decomposed in the generation section having the highest concentration of the discharge products. It can be disassembled before flowing out of the casing, preventing adverse effects on the photoreceptor, etc.
The adverse effect on the environment can be suppressed.

According to the fourth aspect of the present invention, the discharge products generated in the paper separation device can be efficiently decomposed in the generation section having the highest concentration of the discharge products, and the surface of the coating layer can be decomposed. Since the photocatalytic substance is provided, the function of the coating layer is not impaired, so that the discharge product can be decomposed before flowing out of the casing, thereby preventing the adverse effect on the photoreceptor and the like, and also having an adverse effect on the environment. Can be suppressed.

According to the fifth aspect of the invention, in addition to the effect of the first aspect, the photocatalytic substance is included in the coating layer, so that it is not necessary to newly provide a photocatalytic substance coating layer. The coating becomes simple, which is advantageous in terms of production and cost. If the photocatalytic substance is only on the surface of the coating layer, the function will be lost if the coating layer of the photocatalytic substance is peeled off, but if the photocatalytic substance is included in the coating layer, the coating layer will be slightly worn due to discharge etc. Even so, the photocatalytic effect can be maintained because it is also contained inside the coating layer.

According to the sixth aspect of the present invention, the photocatalytic substance can be more strongly activated by the ultraviolet light of the luminous body such as a lamp, so that the discharge products can be efficiently decomposed and the ion generator can emit light. Even when light is not emitted, since the photocatalytic substance can be activated by the ultraviolet light of the luminous body, it can be decomposed even if discharge products remain, thereby discharging the discharge products from the casing As a result, it is possible to disassemble the photoreceptor more reliably, prevent the adverse effect on the photoreceptor and the like, and suppress the adverse effect on the environment.

According to the invention of claim 7, the photocatalytic substance can be more strongly activated by the ultraviolet light of the luminous body such as a lamp, so that the discharge products can be efficiently decomposed, and
Since the photocatalytic substance is disposed on the surface of the light emitting body, it is possible to prevent the surface of the light emitting body from being stained by the adhesion of the discharge product. In addition, when a photocatalytic substance is disposed on the surface other than the light emitting body, even when the ion generator does not emit light, the photocatalytic substance can be activated by the ultraviolet light of the light emitting body, so that the discharge generating Things can be decomposed efficiently. In addition, since the surface of the light emitting body is not stained, the light transmittance of the light emitting body surface does not decrease. Therefore, the photocatalyst can be irradiated with light for a long time, and the photocatalyst can be activated. Thereby, the discharge product can be more reliably decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to the eighth aspect of the present invention, the photocatalytic substance is rapidly activated when irradiated with light of a certain energy or more, and the reaction proceeds. Is 380 nm, the decomposition efficiency of the discharge product becomes very high if the wavelength of the ultraviolet light to be irradiated is appropriately adjusted to create a state in which the photocatalytic substance is more easily activated. Thereby, the discharge product can be more reliably decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to the ninth aspect of the present invention, by using a photocatalytic substance made of an n-type semiconductor having high efficiency as a photocatalytic substance, discharge products can be efficiently decomposed. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to the tenth aspect of the present invention, titanium oxide is an n-type semiconductor photocatalyst and is currently most stable.
Since the titanium oxide is said to be efficient, discharge products can be efficiently decomposed by using this titanium oxide as a photocatalyst. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

According to the eleventh aspect of the present invention, titanium oxide having an anatase structure in its crystal structure has the highest effect as a photocatalyst, so that discharge products can be efficiently decomposed. Thereby, the discharge product can be decomposed before flowing out of the casing, and the adverse effect on the photoreceptor and the like can be prevented, and the adverse effect on the environment can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIGS. 2A and 2B show a configuration example of an ion generating head, in which FIG. 2A is a sectional structural view and FIG. 2B is a plan view thereof.

FIG. 3 is a sectional structural view of an ion generating head showing an example of adding a thermistor.

FIG. 4 is a cross-sectional structural view of an ion generating head showing an example of adding a photocatalytic substance without a coating layer.

FIG. 5 is a cross-sectional structural view of an ion generating head showing an example of adding a photocatalytic substance when a coating layer is provided.

FIG. 6 is a sectional structural view of an ion generating head showing an example of adding a photocatalytic substance to a casing.

FIG. 7 is a configuration diagram showing a case where a lamp is provided.

[Explanation of symbols]

 2 First Image Carrier 14 Paper Separation Device 22 Induction Electrode 23 Dielectric 24 Ion Generation Electrode 30 Coating Layer 40 Photocatalyst Material 50 Light Emitting Material P Second Image Carrier

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takahiko Tokumasu 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Makoto Shino 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H032 AA02 BA23 BA30 DA03

Claims (11)

[Claims] 1. An ion generating electrode comprising an induction electrode and an ion generation electrode formed at least with a dielectric material interposed therebetween, and applying an AC voltage between the induction electrode and the ion generation electrode to cause air discharge to generate ions. Equivalent ion generator is provided as a paper separator, and the first ion generator is used according to the electrophotographic process.
After transferring the image formed on the image carrier to the second image carrier, the ion generating device applies a charge to the back surface of the second image carrier to remove the second image carrier. In an image forming apparatus that facilitates peeling from the first image carrier,
An image forming apparatus, wherein a photocatalytic substance for decomposing a discharge product is provided near a discharge point of the ion generator. 2. The image forming apparatus according to claim 1, wherein the photocatalytic substance is provided on at least the surface of the dielectric on the side of the ion generating electrode. 3. The image forming apparatus according to claim 1, wherein at least the ion generating electrode includes the photocatalytic substance. 4. The image forming apparatus according to claim 1, wherein the ion generating electrode is coated with a dielectric, and has a photocatalytic substance on at least a surface of the coating layer. 5. The image forming apparatus according to claim 1, wherein the ion generating electrode is coated with a dielectric, and at least this coating layer is made of a material containing a photocatalytic material. 6. The image forming apparatus according to claim 1, wherein a light emitter capable of irradiating at least light including ultraviolet rays is provided in the vicinity of the discharge location. 7. The image forming apparatus according to claim 6, wherein the luminous body has a photocatalytic substance at least on a luminous surface thereof. 8. The light emitted from the luminous body has a wavelength of 3
The image forming apparatus according to claim 6, wherein the image forming apparatus includes light having a wavelength of 00 nm to 400 nm. 9. The image forming apparatus according to claim 1, wherein said photocatalytic substance is an n-type semiconductor. 10. The image forming apparatus according to claim 9, wherein said n-type semiconductor is titanium oxide. 11. The image forming apparatus according to claim 10, wherein the titanium oxide has at least an anatase structure.